Vv. Summary.

Recordings of ocular nystagmus were obtained
from a group of cats and a group of human sub-
jects to 4°/sec? angular accelerations of 8.4 sec
and of 36 sec duration. Lateral canals and verti-
cal canals were stimulated on separate trials.
Results showed that the output of both primary
and secondary nystagmus was greater for lateral
canals. In cats, both lateral- and vertical-canal
responses to the 36 sec stimuli peaked after 15-21
sec of angular acceleration and this was followed
by a steady decline. Declines were not apparent
in nystagmus of human subjects. A further test
of these findings was conducted by manipulating
arousal variables; human subjects were given
special tasks and cats received d-amphetamine.

Essentially the same results were obtained as
described above. Other differences between the
two groups were noted. Cats consistently dem-
onstrated secondary nystagmus whereas humans
did not. After termination of acceleration, pri-
mary nystagmus from cats lasted longer and
exhibited a greater number of eye movements
following the 8.4 sec stimulus than following
the 36 sec stimulus; this consistency was not evi-
dent in humans. However, for humans the sen-
sation of motion following termination of ac-
celeration was of longer duration for the 8.4 sec
stimulus than for the 36 sec stimulus. In this
regard, nystagmus from cats resembled the sub-
jective reactions of man more than they did the
nystagmus of man.


AM 67-8

DIAGNOSTIC TESTS OF COLOR DEFECTIVE VISION
Annotated Bibliography, 1956-66

Mark F. Lewis, Ph.D.
Faye K. Ashby

Approved by Released by
he [USdge€ mb
J. Ropert Dixie, M.D. P. V. Srecen, M.D.
Curer, Crvm ArromEDicaL Feperau Arr Surcron
Insrirure
May 1967

FEDERAL AVIATION ADMINISTRATION

Office of Aviation Medicine



man when prolonged high-magnitude angular
accelerations are used.)

It is parsimonious and reasonable to assume
that a single process accounts for (a) the decline
in response during prolonged angular accelera-
tion, (b) the increased response decline following
prolonged acceleration, and (c) the increased
secondary response following prolonged accelera-
tion. The possibility that the cupula endolymph
system is under-critically damped, contrary to
the common supposition, would explain a sec-
ondary response, but this seems at variance with
much of the evidence for the over-damped Tor-
sion Pendulum analogy of van Egmond, Groen,
and Jongkees*? and could not explain findings
(a) and (b). To explain these results on the
basis of cupula deflection, it would be necessary
to assume that the stiffness of the cupula in-
ereases during prolonged constant angular ac-
celeration. Van Egmond, et al?* have proposed
that events within the endorgan (either bioelec-
tric, biochemical or plastic changes within the
cupula) could account for secondary responses,
and this possibility cannot be ruled out. Lowen-
stein** has reported that increasing cupula de-
flection in elasmobranch initiates neural activity
“in one after the other previously silent units”
which often adapt themselves rapidly, Adrian*
and recently Melvill Jones,’ recording from the
vestibular nuclei in cats, found little evidence for
rapid adaptation. However, Cappel* has noted
that slow declines in some units recorded in the
vestibular nuclei of cats correspond temporally
to declines in human subjective data. The pos-
sibility that there is a diminished sensory inflow
during prolonged cupula deflection in cats
remains open.

In man, one aspect of the vestibular reaction
(subjective velocity) declines while another as-
pect (nystagmus) does not decline during pro-
longed acceleration.* From this, it does not
seem reasonable to attribute the decline of the
one response to a suppression of sensory inflow.
(Some reservations are necessary in this inter-
pretation because average curves of different
groups of subjects form the basis of the conclu-
sion. Subjective and nystagmic data from the
same subjects should be compared and studied
for the presence of correlation.) Aschan and
Bergstedt? have evidence which implicates the
central nervous system in secondary responses.
Prolonged primary responses induced by uni-

lateral caloric stimulation should provide an
opportunity for adaptive changes within the
cupula; yet Aschan and Bergstedt? reported
little or no secondary nystagmus with unilateral
caloric stimuli, whereas bilateral hot/cold caloric
stimuli and rotational stimuli, yielding primary
responses of equivalent length, produced sec-
ondary responses.

Although secondary nystagmus (and appar-
ently associated response modulation) in man
and cat are probably attributable to the central
nervous system, it remains quite possible that
some of the differences between man and cat are
attributable to differences in the properties of
endorgans; e.g., the shorter primary nystagmic
response in cats (irrespective of stimulus dura-
tion) is probably attributable to a greater cupula
spring-action in cat, Response parameters of
the central nervous system may be conditioned
or inherently matched to the response parameters
of the cupula-endolymph system so that the
shaping of responses to unusual stimuli may be
similar in form but on a different time base in
different animals.

The conditions under which the “secondary
processes” have been demonstrated, viz. pro-
longed constant angular acceleration, are seldom,
if ever, encountered in natural movement. Even
a single, brief, unidirectional angular accelera-
tion followed by constant velocity does not oc-
cur in natural movement and, as noted in the
present study, intensity of nystagmus continues
to increase briefly beyond the termination of
short unidirectional stimuli. In natural move-
ment, any brief angular acceleration is imme-
diately followed by angular acceleration of
opposite sign which returns the cupula toward
its position of static equilibrium. Hence, in the
case of either brief unidirectional stimuli or
prolonged unidirectional stimuli, the vestibular
reactions fail to follow the theoretical’? cupula
deflection. However, this does not necessarily
signify either an inadequate response: system
within the range of natural movements or a
gross error in theoretical cupula mechanics. The
departure from expected results signifies a range
of unnatural stimuli which is not accurately
followed due to either inaccurate sensory detec-
tion or unfaithful central following of the input,
or both. Because the natural periods of move-
ments of various animals are different,’® it is
quite possible that the ranges of accurate sensory



1.

12,

13,

14.

15.

16.

17.

pected from the Ishihara test although between six

and fifteen errors may indicate a mild defect.

Cottins, W. E., Casora, A. S., & Zecers, R. T. The
performance of color-blind subjects on the color
aptitude test. J. Gen. Psychol., 64 :245-250, 1961.

The paper compared the performance of color de-

ficient subjects on the Color Aptitude test with

performance on the Hardy-Rand-Rittler plates. The
results show that the color defectives had poor
scores on all color series of the Color Aptitude test.

There was some evidence that lower scores on the

red series may indicate a protan-defect, while lower

scores on the green series may indicate a deutan-
defect.

Coxomer, A., ViTatr, G., & Carta, F. Impiego di
una funzime discriminante nella valutazime della
capacta diagnostica delle favole di Ishihara.
Annal. Ottal. Clin, Ocul., 91:954-961, 1965.

This paper described the use of a discriminative

function in the evaluation of the diagnostic efficiency

of the Ishihara plates.

Crawiorp, A. A description of an anomaloscope.
Brit. J. Physiol. Opt., 8:178-175, 1951.

This paper described a simple filter anomaloscope.

Crawrorp, A. The Dyorine pseudo-isochromatic
plates. Brit. J. Psychol., 46:139-143, 1955.

This is a review of the second edition of the Dvorine

pseudo-isochromatie test. The reviewer concluded

that the test is an effective screening test for sepa-
rating color defectives from color normals,

Crone, R. A. Clinical study of color vision.
J. Ophthal, 39:170-178, 1955.

This paper described a modification of the Nagel

anomaloscope, which permitted determination of

(1) relative luminous efficiency of spectral light,

(2) thresholds of wavelength discrimination in the

spectrum, (3) thresholds of saturation discrimina-

tion in the spectrum, and (4) trichromatic coeffii-
cients of spectral colors.

Crone, R. A. Quantitative diagnosis of defective
color vision: A comparative evaluation of the
Ishihara test, the Farnsworth dichotomous test,
and the Hardy-Rand-Rittler polychromatic plates.
Amer. J. Ophthal., 51 :298-305, 1961.

‘The paper compared the pseudo-isochromatic plates

of Ishihara with the Hardy-Rand-Rittler plates and

the Farnsworth Dichotomous test. The threshold
of wavelength discrimination at 590nm was taken
as a measuring rule. The Ishihara plates proved
excellent for differentiation between normals and
abnormals but were unsuitable for quantitative dif-
ferentiation. The H-R-R plates, on the contrary,
were unsuitable for differentiating between normals
and abnormals, but were very good for quantitative
differentiation. For the latter, the Farnsworth

Dichotomous test was also usable though to a lesser

degree.

Dimick, R. L. & Wienxy, R. E, How red is red?
Amer, J. Psychol., 71 :298-304, 1958.

Selected portions of the red end of the spectrum

were evaluated. The results indicated that the use

of different primaries in anomaloscopes will result

Brit.

18.

19.

20.

21,

in slightly. different red-green ratios. The results
indicated that the red-green ratio is a function of
the luminance level of the yellow comparison stim-
ulus. The authors suggested that more rigorous
results may be obtained in anomaloscopic examina-
tions if the yellow comparison stimulus is at a fixed
luminance level.

Dvorrne, I, Quantitative classification of the color

blind. J. Gen. Psychol., 68 :255-265, 1963.

A comparative study of 34 color vision defectives
disclosed that 19 of them were diagnosed alike with
the Dvorine, H-R-R, and Tokyo Medical College
tests; the Dvorine and TMC tests were in agreement
quantitatively in 27 of 34 cases; the Dvorine and
the H-R-R were in agreement quantitatively in 25
of 34 patients; and the H-R-R and TMC were in
agreement quantitatively in 20 of 34 cases presented.
The author concluded that failure to pass a color
vision test which is based on progressive increase
of chroma in polychromatic plates (H-R-R and
TMC) would seem less effective an indicator of the
extent of color vision deféct than the estimation of
the deficiency from the number of missed plates or

errors on the Dvorine test.

Dvortne, I. The importance of color vision in the
military services. Optom. Whly., 54:1191-1195,
1963,

The author described the various types of color
vision tests in use. He recommended the pseudo-
isochromatic test above all other types, but sug-
gested that the armed services must have their own
set of plates designed for their exclusive use.
Farxswortn, D. The Farnsworth-Munsell 100 hue
and dichotomous tests for color vision, J. Opt.
Soc. Amer., 33 :568-578, 1943,
‘This paper described the construction and use of the
Farnsworth-Munsell 100 Hue test and the Farns-
worth Dichotomous test for color vision,

Farnswortu, D, ‘Testing for color deficiency in
industry, A.JLA. Archs. Ind. Hith., 16 :100-108,
1957.

A four-part classification of color vision was sug-
gested based upon whether applicants pass or fail
pseudo-isochromatic plates, the Farnsworth Lantern,
or the Farnsworth D-15 Dichotomous test. An ap-
plicant who passed all three tests was described as
normal. An applicant who passed the lantern and
the Dichotomous test but failed the plates was
classified as a mijld defective. An applicant who
passed the Dichotomous test but failed the plates
and the lantern was described as moderate defec-
tive. An applicant who failed all three tests was
classified as a severe defective.

. Farnsworth, D. & Foreman, P. Development and

trial of the New London Navy lantern as a selec-
tion test for serviceable color vision, BuMed
Project X-457 (AV-241-K), Color Vision Rpt. No.
12, 6 May 1946, U.S. Submarine Base, New. Lon-
don, Connecticut.
A color vision testing lantern was designed which
was intended to be as quick and convenient to give
as pseudo-isochromatic plates or other standard


ACKNOWLEDGMENTS

Dr. Collins is Chief, Psychology Laboratory, Civil Aeromedical Insti-
tute; Dr. Guedry is Chief of Experimental Psychology, Research Department,
USN Aerospace Medical Institute, Pensacola, Florida.

This study was conducted at the Civil Aeromedical Institute in Okla-
homa City with the technical assistance of Billy P. Updegraff, Ruth Ann
Mertens, and Kathryn Quattlebaum.

Qualified requestors may obtain Aviation Medical Reports from Defense Documentation
Center. The general public may purchase from Clearinghouse for Federal Scientific and
Technical Information, U.S. Dept. of Commerce, Springfield, Va, 22151




Orthorator—51
Pickford Anomaloscope—58, 59
Pickford-Nicolson Anomaloscope—39, 45,
Polack Plates—26, 27, 28, 29, 38, 70, 71
Pseudo-Isochromatic Plate Tests
See: AOC Plates
Bostrém Plates
Bostrdm-Kugelberg Plates
Dvorine Pseudoisochromatic Plates
International 16 Plate Selection
Ishihara Plates
Meyrowitz Plates
Polack Plates
Rabkin Plates
Sloan-Habel International 20 Plate Selection
Stilling Plates
‘Tokyo Medical College Color Test
Yustova Plates
Rabkin Plates—23, 24, 25, 26, 28, 29, 30, 83, 34
Rautian Anomaloscope—23, 61

~ 10

RCAF Lantern—48

RCN Lantern—8, 22

SAM-CTT (School of Aviation Medicine Color Threshold
‘Tester )—35, 36, 37, 60, 65, 70, 71

Schmidt-Haensch Anomaloscope
See: Nagel Anomaloscope

Sloan-Habel International 20 Plate Selection—71

Sloan Selection
See: International 16 Plate Selection

Stilling Plates (Velhagen)—7, 25, 27, 42, 43, 72

‘Tokyo Medical College Color Test (TMC)—18, 26, 28, 29,
48, 47, 64, 70, 75, 83

28 Hue Test—63

‘Two-Color Threshold—5

Velhagen Plates
See: Stilling Plates

Wool Test
See: Holmgren Wool Test

Yamamoto Color Test Plates—82

Yustova Plates—24



air, and total oxygen may be derived according

to the following calculations :
Per Cent Dilution = Scare

Oxygen from supply = 100 Per cent of dilution

Oxygen from ambient = Per cent dilution +

oxygen from ambient

Total oxygen = oxygen from supply + oxygen

from ambient

Calculated inspired oxygen partial pressure =

(Ps - 47) x Per cent total oxygen

Where: P, = Total pressure in mm Hg at am-
bient altitude.

47 = Pressure, in mm Hg, of saturated

water vapor at body temperature.

A Waters ear oximeter was affixed to the anti-

helix of the ear of each subject in order to obtain

blood oxygen saturation under all conditions. A

CHAMBER
WALL

‘OXIMETER AMPLIFIER

Statham pressure transducer was connected to
the system in order to record the line pressure
response of the regulator to altitude. Closed
circuit television was utilized in order to monitor
each subject’s condition. Motion picture pho-
tography was also used to record the reservoir
bag condition and volume. Instrumentation of
the subjects is shown in Figure 5.

A bicycle ergometer was modified so that it
could be operated by each subject while seated
in an aircraft type seat. After the subject was
instrumented and ground level baselines recorded,
the chamber pressure was decreased to equivalents
of 10,000 and 14,000 feet for recording of addi-
tional air breathing baselines. Chamber pres-
sure was then increased to an equivalent of 8,000
feet in order to determine the subject’s ability
to equalize middle ear pressure. After the sub-
ject had donned the test mask, the chamber

AND MONITOR

NITROGEN

u,

OXYGEN
12 SUPPLY my

LINE PRESSURE

PLUG IN ORF:
RECORDER we

ELECTROCAROIOGRAPH

fvercaron a

IMPEDANCE
PNEUMOGRAPH

=a

WASAL SAMPLER =@ INTEGRATOR © EAR OXIMETER
ELECTROCARDIOGRAPH LEADS © IMPEDANCE PNEUMOGRAPH LEADS
STATHAM PRESSURE TRANSDUCER

@ constant FLow REULATOR

Figure 5.—Instrumentation of subjects and diagram of oxygen system.


Hypoxic hyperventilation does not produce
this same effect when air is breathed at, for ex-
ample, 14,000 feet, since the inspired partial
pressure remains constant. Similarly, at higher
altitudes when demand oxygen equipment is used,
the ratio of oxygen to air is accomplished by the
demand regulator which is so designed and pro-
grammed that this ratio remains constant at a
specific altitude regardless of the ventilation and
respiratory activity of the mask wearer. How-
ever, with constant flow systems and masks, dilu-
tion ratios at a specific flow rate are largely
determined by introduction of ambient air into
the mask. Mask design, phase of the respiratory
cycle in which dilution occurs, inspiratory flow
rates and volume are the determiners of the
oxygen/air ratios at a specific oxygen flow.

Although it was not measured, CO2 accumula-
tion in the rebreather bag did not appear to
present a problem with the prototype masks.
In previous mask evaluations it was found that
the use of rapid response infra-red CO, analyzers
which require relatively high sample flow rates
compromised the determinations of end expira-
tory gases. Since the minimum required sample
flow of 250 cc per minute represented a signifi-
cant portion of the inspired gas, it could not be
discarded but was returned by a closed circuit
to the rebreather bag. However, as the sample
was returned to the rebreather bag continuously
and not in phase with the respiratory activity of
the subject, measurement of other expiratory
gases was rendered erratic and erroneous.

The respiratory center is very sensitive to
CO, and it is anticipated that had significant
quantities of CO, accumulated in the rebreather
bag, the subject’s respiratory rate would have
been increased out of proportion to that expected
for the degree of activity in which the subject

was engaged. These data do not indicate this
response.

It must be realized that these evaluations were
carried out at altitude on young, healthy male
subjects under favorable conditions with the
masks correctly donned and providing a good fit
to the face. Under actual conditions of use, care
and caution may not be extended to this degree.

V. Summary and Conclusions.

1. Oxygen flow as provided by the Scott Oxy-
matic automatic constant flow regulator, when
used in conjunction with either of the prototype
phase dilution—rebreather test masks and proper
orifices, was sufficient to maintain the subjects’
indicated blood oxygen saturations equal to or
in excess of their ground level (1,278 feet) base-
lines.

2. With the same oxygen flow rates the proto-
type porous and dilution valve masks provided
higher tracheal oxygen partial pressures than
the open port masks at all altitudes tested during
rest and exercise.

3. The slight reduction of flow rates as pro-
vided by the Scott Oxymatic regulator when
eight orifices were plugged into the system as
opposed to one orifice is not considered to com-
promise significantly the performance of the
system.

4, Heart and respiratory rates of all subjects
indicate normal response, with the maximum
generally occurring during exercise and hypoxia
induced during establishment of air breathing
baselines at 14,000 feet.

5. At the same flow rates a greater amount
of oxygen was derived from the supply and less
lost by the prototype phase-dilution rebreather
masks as compared to the open port type mask.


Each author’s name is followed by the identification number of the reports on which his name

appears.

Awaya, S.—47
Bailey, R, W.—1
Baker, H. D—2
Baron, J.—3
Belcher, 8. J—4
Bouman, M. A—79
Boynton, R. M—5
Brooks, R.—82
Burnham, R. W.—6
Cabau, A—3
Cameron, R. G.—7
Carta, F,—12
Casola, A. S—11
Chapanis, A.—8, 9
Clark, J. R—6
Cole, B, L.—10
Collins, W. E—11
Colombi, A.—12
Crawford, A.—13, 14
Crone, R. A.—15, 16
Defayolle, M.—51
Dimmick, R. L.—17
Dvorine, I.—18, 19
Farnsworth, D.—20, 21, 22, 80
Flekkel, A, B,--23, 24
Foreman, P.—22
Frey, R. G.—25, 26, 27, 28, 29, 30
Fukuda, T.—69
Gallagher, C, D.—31
Gallagher, J. R—31
Goldstein, A.—32

AUTHOR INDEX

Greenshields, K. W.—4
Habel, A—71
Haefner, R.—33
Hardy, L, H.—34, 35, 36, 37
Hioki, R.—38
Homberg, L.—89
Hoogerheide, J.—40
Ichikawa, H.—50
Joshi, V. G.—41
Katavisto, M—42, 48
Kirsechen, M.—44
Kurata, K.—69
Lakowski, R.—45, 59
Leebeek, H. J.—78, 79
Linksz, A—46
Majima, A—47, 50
McCulloch, C.—418
Munteanu, M.—49
Nakagawa, 0.—50
Nakajima, A—50
Nakamura, Y.—38
Obi, 8.

Parmentier-Beloux, M.—3
Péchoux, R—51

Perdriel, G.—52, 53

Peters, G.—54, 55, 56
Pickford, R. W.—57, 58, 59
Rand, G.—34, 35, 36, 37, 60
Rautian, G. N—61

Raymond, R.—51

Resseguier, J.—51

Rittler, M. C.—34, 85, 86, 87, 60
Riu, R62

Roth, A.-63

Sawa, J.—64

Schmidt, 1—65, 66

Seefelt, E. R.—67, 68

Seki, R.—69, 75

Sloan, L. L.—70, 71

Smiley, J. R.—48

Stams, A—72

Tajiri, K—69

Tanabe, S.—47

Topley, H.
‘Tsutsumi, S—74
‘Turnour,
Umazune, K.—75

Vies, I. L—76

Vitali, G.—12

Wagner, M—5

Walls, G.—77
Walraven, P. L.—78, 79
Watanabe, M.—50
Wienke, R. E.—17
Willis, M. P.—80
Wright, W. D.—4, 81
Yamamoto, 'T.—82
Yoshihara, M.—83
Zegers, R. T—11



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Qualified requestors may obtain Aviation Medical Reports from Defense Documentation
Center. The general public may purchase from Clearinghouse for Federal Scientific
and Technical Information, U.S. Dept. of Commerce, Springfield, Va, 22151


in a manual assay with appropriate concentra-
tions of a primary standard such as reduced
glutathione. Thiocholine iodide may now be
purchased from the Pierce Chemical Company,
Rockford, Illinois.

The apparent enhancement of the dialysis of
glutathione by unhydrolyzed acetylthiocholine is
interesting. Of course, we have not completely
ruled out the possibility that glutathione causes
hydrolysis of the substrate in the automated sys-
tem, but the lack of influence by glutathione in
the manual method makes this unlikely. The
pH is quite stable in both methods, even in the
presence of large concentrations of enzyme. In
any case, the possibility of mutual interference
during analytical dialysis should be considered
when this module is employed. For example, in
the analysis for total non-protein sulfhydryl
present in a biological sample, one might be hard
pressed to select a proper standard, for, not only
might the dialysis of individual molecular species
be influenced by other components of the sample,
but, as dialysis is usually incomplete, some vari-
ability might be introduced through differences
in rates of diffusion. Of course, this problem
might not obtain in the analysis of individual
compounds for which specific quantitative reac-
tions are available, but recovery experiments
would be necessary to rule out possible interfer-
ence in dialysis even though this had already
been checked in the manual procedure.

HI. Calculation of the Enzyme Unit.

“One unit (U) of any enzyme is that amount
which will catalyze the transformation of 1
micromole of the substrate per minute under de-
fined conditions.” This unit, as defined by the
Commission on Enzymes of the International
Union of Biochemistry is more acceptable to us
than the unit based on 3 minutes used by Garry
and Routh in a manual method* and Levine,
Scheidt and Nelson in the automated version of
this method. A “3 minute” unit is even less
meaningful in the automated procedure, for, al-
though Garry and Routh employed a 3 minute
incubation time ,the incubation time of approxi-
mately 4 minutes used in the automated method
cannot be precisely known due to the complex
analytical conditions; the enzyme and substrate,
after mixing, pass through connecting tubing
(not at 37°C) into an incubation coil (387°C)
and then into the dialyzer module (37°C) where
the products (and the substrate) are removed

from the non-diffusable enzyme at an unknown
rate. This removal of products may accelerate
the enzyme reaction; on the other hand, the re-
moval of some of the remaining substrate could
slow the reaction rate. Thus, in order to make
the data obtained from our automated analyses
meaningful to those who do not possess this
equipment, we established a conversion factor by
analyzing several enzyme preparations by both
the automated and a manual procedure. The
enzyme solutions were made from a highly puri-
fied preparation of electric eel cholinesterase;
these solutions did not absorb light at 420 mu,
a decided advantage in the manual technique.
The manual method used was essentially that of
Gary and Routh except that we used phosdrin
to stop the enzyme reaction. One example is
given here to demonstrate the calibration pro-
cedure: A single dilution of electric eel cholin-
esterase was assayed by both methods. Hydro-
lyzed acetylthiocholine was used as the standard
in each case. In the manual assay, after correc-
tion for chemical hydrolysis the enzyme con-
centration was calculated to be
590 umoles (SH)
ml-min
or 590 U/ml. In the automated assay the same
enzyme dilution produced a change in absorbance
equal to a standard concentration of 2680 umoles
(SH)/ml. Thus, the “true” or “effective” in-
cubation time for the automated procedure may
be calculated
2680 umoles x ml-min

ml 590 umoles
and this may be used to calculate units from ex-
perimental data (e.g. :
908 umoles x 1 = 200U )

ml 4.54 min ml .
Subsequent experiments have shown this factor
to be constant over several months but changes
in pumping rates and in the dialysis membrane
would result in changes in the calibration factor
and this must be watched for,

IV. Cholinesterase Inhibition in Poisoned Rats

Our main interest in the automated method
was to employ it in the detection of organophos-
phorus poisoning in experimental animals. Thus.
it was important to test this newer method against
another, more established technique. Mr. Joe
Rieger, Mr. Leonard Ryan and Dr. W. B. Sta-
vinoha collaborated with us in a comparison

= 4.54 min.,



40 -

30 F

PRIMARY NYSTAGMUS

—
e.
/ ee HUMANS
° e

SUBJECTIVE RESPONSES
4——A PRESENT STUDY

4— — 4 GUEDRY, CRAMER,
& KOELLA, 1958

POST-STIMULUS RESPONSE DURATION IN SECONDS

tL
lof o——° Oo ~~a
—$__
PRIMARY NYSTAGMUS °
5 FROM CATS
at 1 1 L 1 1 1 i L J
5 10 15 20 25 30 35 40 «45 ~~ 50
TIME IN SECONDS

Ficure 3. Duration of the post-stimulus subjective and nystagmic reactions obtained in this study are com-

pared with subjective data from an earlier study. The abcissa represents stimulus duration.

Functions de-

picted for the two sets of subjective data and for primary (slow-phase displacement) nystagmus from cats are

in close agreement.

where the mean subjective turning scores from
the present study are presented along with sub-
jective data obtained in a previous study. In
this earlier study,'* subjects had been trained in
making subjective reports, whereas the present
subjects had no preliminary practice. The rise
and decline in duration of human nystagmus
and subjective response as stimulus duration in-
creases is also matched fairly well by the change
in temporal characteristics of nystagmus in the
eat, also shown in Figure 3, Reference to Tables
2 and 8 shows that, in both man and cat, time
elapsed from stimulus termination to onset of
secondary nystagmus increases and declines in a
manner which approximately parallels duration
of the primary reaction.

Secondary nystagmus was not evident in the
recordings of any of the human subjects for the
1.2 and 3 sec stimuli, and several subjects gave
no secondary response to the 30 sec stimulus.
However, frequency of otcurrence of secondary
nystagmus increased with stimulus duration, and
this may be interpreted as evidence for a rela-
tionship between stimulus duration and intensity
of secondary response in humans similar to, but
more variable than, that observed in the cat. In
comparison with secondary nystagmus of the
cat, the secondary nystagmus in man has a later
onset, lower average intensity (relative to man’s
primary reaction), and seems to be more subject
to individual differences.

Tables 2 and 38 suggest that the number of



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at /\
70F “ \ “\

>
Sx
~x
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ha
« zir~o mx 5
a a _ ‘ N ~ “x
a Ong \
* \
a \ ° x
\ \ / . \
‘a. \ 7 ° \

n
3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51

50- SECONDARY NYSTAGMUS

SLOW - PHASE NYSTAGMUS
- n
fo} co}
os
TM,
‘
> Ze
27
rie

2

4ob aN o—e TRIAL |
—— e X——x TRIAL 5
30f J. / \ o——o TRIAL 10
x
OX \ a——4 TRIAL 15
20h — \.
XT \ AVERAGE FOR 6 CATS
mK
lob \ Se .—e.
.
7 oa ON
14 < WEIS cise

3.6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51
TIME IN SECONDS

‘auRE 3. ‘Time-course plots of slow-phase eye displacement for trials 1, 5, 10, and 15 of the habituation series.
With repeated trials there occurs a depression of output with early peaking followed by vapid declines during
the accelerations. Effects are similar for both primary and secondary nystagmus.

9



beats of secondary nystagmus is more closely
related to the duration of primary post-stimulus
nystagmus than to the duration of the stimulus.
This is in contrast to the maximum slow-phase
velocity of secondary nystagmus which seems
related to the stimulus duration, at least in the
cat (see Figure 1). The decline in number of
secondary beats with stimuli longer than 15 sec
may signify an encroachment of the secondary
reaction on the primary reaction.

Primary nystagmus in the cat is shorter in
duration and has a lower beat-frequency than
that of man for the range of stimuli investigated.
There is also a pronounced difference between
man and cat in regard to the intensity-ratio of
secondary to primary nystagmus, the ratio being
higher for the cat.

A log plot of nystagmus slow-phase velocity
with respect to time also shows the cat to have

30 cr
255 \ Human [O—9 30 SEC
20 f, NS e@--© 9 SEC
rsh \ _
Fis t\. cat [4-4 30 SEC
8 Mae ONG a--A 9 SEC
a VON,
Be lop \
r] N,
oe os
23 4
SE \
co}
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ao ‘
1hé
a~ \ \
a \ vi
| \\
Ss \ e

14
3.6 9 [2 15 18 21 24 27 30 33 3639 42
TIME IN SECONDS

Ficure 4. Log plots of slow-phase eye velocity follow-
ing two stimulated durations for cat and human
subjects. Data represent nystagmus measured from
the point of stimulus termination and thus depict
the rates of response decay. Decay is more rapid
in cats and the longer stimulus duration produces
more rapid declines.

a substantially different rate of decline of nys-
tagmus (lower time constant) than man for
comparable stimuli (see Figure 4). It also ap-
pears that the slope of nystagmus decline for both
man and cat changes as a function of stimulus
duration, the. longer stimuli producing post-
stimulus nystagmus with a higher rate of decay
(lower time constant).

V. General Discussion

Because neurophysiological data from cats are
sometimes applied to the explanation of reactions
in man, it is important to compare the same
response variables in men and cats exposed to
identical vestibular stimuli. Nystagmus in cats
declined during prolonged constant angular ac-
celeration in spite of efforts to maintain alert-
ness, whereas nystagmus in alert men did not
decline during prolonged angular acceleration;
the rate of decline of primary vestibular nys-
tagmus following each stimulus was greater in
cats than in man; the ratio of secondary to pri-
mary nystagmus was higher in cat than in man.

If it is assumed that secondary nystagmus
reflects a process which develops during the pri-
mary reaction and opposes its continuation, then
all of the differences between man and cat may
be due to this secondary process in cat having a
more direct control of nystagmus than does its
counterpart in man. The characteristics of sub-
jective data reported by man resembled the
alterations of nystagmus in cats during and after
prolonged angular accelerations? and in some
respects the nystagmus of man deviates from
both the nystagmus of cat and the subjective
responses of man during and after these unusual
stimuli. It appears that the hypothesized sec-
ondary process exerts a control on man’s sensory
experience, i.e, the perceived angular velocity,
comparable to the control of nystagmus in the
cat. This is not to say that the nystagmus of
man is completely without the modulating in-
fluence of this secondary process because the rate
of decline of both post-stimulus primary nys-
tagmus and the occurrence of secondary nys-
tagmus were influenced in man by the duration
of the stimulus. However, the control is appar-
ently less consistent and, hence, probably less
direct for the range of stimuli used in the present
experiment. (Subsequent experiments have il-
lustrated a pronounced secondary nystagmus in


although the mean group data for “duration of
primary nystagmus” and for “time from end of
stimulus to start of secondary nystagmus” were
longer for: the 8.4 sec stimulus, the differences
were slight. Mean number of beats of primary
nystagmus following stimulus termination ac-
tually favored the 36 sec over the 8.4 sec stimulus,
but the differences were not significant. Thus,
results obtained from the cats, in which the post-
stimulus nystagmic responses to the 8.4 sec stim-
ulus consistently exceeded those of the 36 sec
stimulus, were not borne out in the data from
human subjects.

Tate 4, Time in seconds from end of each rotatory
stimulus to end of subjective turning experience for uaman
subjects. Each value is a mean for an acceleration and a
deceleration stimulus. Stimuli were 4°/sec? for either 8.4
or 36 seconds.

Lateral Canals Vertical Canals

Subject 8.4 36 8.4 36
Nu wees aoe weee
Or 29.5 12.5 9.3
Me 34.5 12.4 44.0 9.2
Wa 27.8 14.9 10.4 23.7
Pe 11.0 6.7 7.7 2.0
Fr 23.1 14,3 11.5 28.6
Jo 20.4 12.4 19.9 -1.3*
Ma 7.7 3.1 74 —15.1*
M= 20.8 13.3 16.2 8.1

“Subjective turning experience ended during stimulus.

Human subjective data (Table 4), in 11 of 13
comparisons (3 comparisons were not obtained),
showed that the 8.4 sec stimulus resulted in sen-
sations of longer duration after termination of
angular acceleration than did the 36 sec stimulus.
For two subjects the sensation to vertical canal
stimulation ended during the 36 sec stimulus.

Time plots of the nystagmus recorded during
the two stimulus conditions appear in Figure 5.
Responses from the lateral canals were of greater
magnitude than those from the vertical canals.
No clear peaking or decline in output during the
stimulus appeared for either set of canals. Sec-
ondary nystagmus was plotted in the same figure.
However, of the 8 subjects, 6 gave no scorable
secondary responses to the 8.4 sec lateral canal
stimulus, 5 gave none to the same stimulus ap-
plied to the vertical canals, 3 gave none to the 36

sec vertical canal stimulus, and one gave no scor-
able secondary nystagmus to the 36 sec lateral
canal stimulus. Thus, in two general respects,
human data differed from cat data: 1) humans
did not show a rise and decline during prolonged
(36 sec) stimulation whereas the cats did; 2)
little or no secondary nystagmic reactions to the
8.4 sec stimuli were demonstrated by humans
whereas cats consistently gave such responses.

Arousal. The importance of arousal on nys-
tagmic responses was noted earlier and has been.
examined in considerable detail elsewhere.? To
assure reliability of the present data with regard
to this factor, a second group of 10 cats was
treated with d-amphetamine in accordance with
procedures described by Crampton and Brown.’
Each animal received 4 trials with each trial
comprising an acceleration stimulus of 4°/sec?
for 36 sec, 2 min of constant velocity, and a sub-
threshold deceleration (0.15°/sec?). The first
two trials were always stimulation of the lateral
canals; the remaining two trials involved verti-
cal canal stimulation. Trials were alternately
CW and CCW. Half the animals began with
CW rotation; the remaining 5 began with CCW
rotation. Data from CW and CCW accelerations
were similar for the horizontal and the vertical
nystagmus curves and, therefore, were averaged.
The mean response curves for the 10 animals
appear in Figure 6 and demonstrate the same
type of decline during stimulation and almost.
identical transition points from primary to sec-
ondary nystagmus as those presented by the un-
drugged cats. Vertical nystagmus again shows
& more pronounced decline during stimulation
than does horizontal nystagmus. Some suppor-
tive neural data for this decline of response
during stimulation of the cat has been presented
by Cappel? who showed plots of single neural
unit activity during a prolonged angular ac-
celeration and reported a rise and decline of
firing during the stimulus period.

A reliability check of the findings for humans
was accomplished by exposing 4 males and 4
females, all previously untested, to stimulus
conditions (4°/sec? for 36 sec) identical to those
administered to the other human subjects. Half
of the males and females received CW stimula-
tion, the remaining half received CCW rotation.
Four trials were administered, two each for the
lateral and vertical canals. The first two trials
always employed mental arithmetic (MA) as


@-Orifice supplied with new prototype
2 mask incorporating a porous dilution
a valve. One outlet of system in use.
5 A 45h Scott automatic constant flow oxygen
o regulator No. 25620-3. Supply
w & pressure to regulator 335 p.s.i.
N
2 40F .
Sf
oO
Ras fa
OE ©
& q 3.57 °
ES
72
L ry
BE sO be
Se
ho
Ze 25F
we
S
x
i} 2.0F 8
O- Same orifice with seven additional Scott
Sky masks added to the system.
LS 1 4 4

15 20 25 30 35
ALTITUDE THOUSANDS OF FEET

Ficure 8—Oxygen flow as determined by regulator and
orifice as supplied with mask described above. Plot
of data from Table IV.

@-Orifice supplied with new prototype
mask incorporating a solid dilution
a valve, mask mounted microphone and
~& A. 4.55 Duo-Seal valve. Scott automatic constant
BS flow oxygen regulator No. 25620-3.
° Supply pressure to regulator 335 p.s.i.
a One outlet of system in use. °
25 797 Tf,
= £ é ve
= .
9 — 3.57 °
a 8
EO
ae
3 e,
o 3.0F 2
= =
Se
ae 2s
gs ~
oN
Qe
3S 2.0F
©-Same orifice with seven additional
Scott Sky masks added to the system.
15 L 1 1 1

15 20 25 30 35
ALTITUDE THOUSANDS OF FEET

Fraure 9.—Oxygen flow as determined by regulator and
orifice as supplied with mask described above. Plot
of data from Table V.

Ill. Results.

Oxygen flow as provided by the regulator was
sufficient to maintain the subjects’ indicated
blood oxygen saturations well above their 10,000
and 14,000 feet baselines and equalled or ex-
ceeded their ground level (1,273 feet) baselines
(Tables 1, 2 and 3). It should be emphasized
that the masks were carefully fitted to the sub-
jects to provide a good seal to the face. Addi-
tionally, all subjects were young, healthy males
24-88 years of age with previous high altitude
experience.

From the standpoint of relative efficiency,
calculated inspired oxygen partial pressures in-
dicate that the phase dilution masks which in-
corporated either a porous dilution port or a
dilution valve were comparable (Figures 10 and
11). The open dilution port mask produced
lower tracheal oxygen partial pressures at all
altitudes during rest and exercise. The effect
of one minute of reading aloud was evaluated
at 30,000 and 34,000 feet with this mask. This
activity, due to high peak inspiratory flow rates
and mask displacement, reduced the tracheal
partial pressure to a greater extent than did
exercise (Figure 11). However, since reading
was limited to one minute, the reduced tracheal
partial pressures did not appear to produce a
significant effect upon the blood oxygen satura-
tion.

The flows as provided by orifices furnished
with the porous dilution port mask and solid
dilution valve may be compared in Tables 4 and
5. Although the orifice furnished with the
prototype mask incorporating a solid flutter
type dilution valve provided slightly higher flow
rates, this appears to be a function of manufac-
turing tolerance.

IV. Discussion.

The Scott Oxymatic automatic constant flow
regulator when equipped with the proper orifices
and efficient masks is designed automatically to
provide sea level equivalents of oxygen flow to
an altitude of 30,000 feet. Physiological evalua-
tion of subjects at altitude indicated that the
system, when utilized with new prototype re-
breathing masks, maintained the subject’s blood
oxygen saturation and inspired tracheal oxygen
partial pressure equal to or in excess of the
ground level equivalent. Masks of this type
provided higher and more consistent tracheal


1l00r- °

90F ‘

80

60-F

x PARAOXON
° SEVIN

40+

30

ChE ACTIVITY, % OF CONTROL

1Or

0 10 20 30 40 50 60 70 80
MINUTES AFTER DILUTION

Figure 4, Reversibility of inhibition by Sevin after dilution of whole blood. Concentrations of Sevin (in undiluted
sample) from top: 1, 10 and 100 x 10-6M. Concentrations of paraoxon: 3, 4 and 5 x 10-7M.

8


Taste 2. Measures of primary nystagmus following
the termination of each rotatory stimulus for cats.
Each response value is a mean of responses to an
acceleration and a deceleration stimulus, Stimuli
were 4°/sec* for 1.2, 3, 9, 15, 21, or 80 seconds.

Time From End of Stimulus to End of Primary
Nystagmus (Sec)

Cat 12 3.0 9.0 15.0 21.0 30.0
108 10.9 12.4 14.6 10.6 81 6.0
109 5.9 8.3 82 5.4 4.0 16
110 18.5 73 9.2 12.0 5.0 23
it 71 111 88 65 43 12
112 3.0 12.4 11.6 15.7 12.2 10.8
113 28 11.8 9.8 9.4 6.0 38
114 8.2 11.6 9.3 8.0 13.6 6.8
115 10.2 8.0 10.2 106 13.1 9.0
116 115, 12.1 14.2 15.3 124 13
7 76 3.0 82 9.3 6.2 5.0
us 8.9 12.3 13.3 13.3 12.5 12.1
119 10.4 10.7 72 5.0 72 2.5
M= 88 101 10.4 10.1 87 65

Time From End of Stimulus to Start of Secondary
Nystagmus (See)

108 15.6 15.4 20.8 15.60 145 18.2
109 79 16.9 13.5 9.9 6.5 62
110 15.9 6.6 12.9 6.0 8.4 6.7
i 15.0 16.8 12.6 10.8 75 (10.6
112 —_ 14.6 175 24.4 20.4 18.1
113 15.7 18.3 14.1 116 9.0 15
14 12.5 12.7 14.7 25.4 154 15.6
115 17.3 19.5 14.6 16.7 15.0 14.0
116 13.6 16.9 21.3 175° «1540 161
117 11.2 18.0 14.8 12.6 13.0 © 15.6
118 93 16.3 15.3 15.5 16.4 7
119 15.2 14.9 11.8 114 95 a1
M= 13.6 15.6 15.3 14.8 12.6 12.2

Beats of Primary Nystagmus After End of Stimulus

108 2.0 12.0 19.0 125 115 6.5
109 15 7.0 9.0 6.5, 2.5 1.0
110 3.0 3.0 6.5 65 4.0 3.0
11 25 10 85 70 4.0 2.0
112 25, 8.0 140 185 «16.5 95,
113 2.0 15 9.5 9.0 5.0 3.0
114 55 8.5 12.0 75 17.0 5.5
115 45 7.0 85 9.5 16.5 10.5
16 55 8.0 16.0 18.0 9.5 18.5
117 4.0 5.0 —_ 8.5 5.0 12.0
118 12.0 15.5 17.0 19.5 19.0 15.0
119 4.0 8.0 5.5 45 7.0 15

— > — rr

M= 41 8.0 14 10.6 o8 73

Taste 8. Measures of primary nystagmus following
the termination of each rotatory stimulus for human
subjects. Each response value is a mean of re-
sponses to an acceleration and a deceleration stim-
ulus. Stimuli were 4°/sec* for 1.2, 3, 9, 15, 21, or
30 seconds.

Time From End of Stimulus to End of Primary
Nystagmus (Sec)

Subject 12 3.0 9.0 15.0 21.0 80.0

Pa 22.0 11.0 17.3 32.0 168 223
Da 12.6 25.2 42.4 541 646 ©6458
Br —_ 28.8 20.5 25.7 87.5 = 29.6
Do 18.3 19.6 38.9 513 36.3 © 89.8
Ch 13.1 25.1 40.0 33.0. 245 23.9
Ro 13.6 41.3 28.4 34.9 44.2 40.5
Ve 10.9 62.2 44.0 413 884 87.9
Te —_ 20.9 42.6 26.7 33.1 272
Dt 318 42.0 44.4 484 40.1 85.7
Sa 21.3 22.3 55.6 44.1 32.8 288
Pz 73 29.1 51.9 40.3 89.2 28.5
Dy 17.6 46.3 42.4 45.6 33.7 29,2
M= 16.9 812 39.5, 898 368 32.4

Time From End of Stimulus to Start of Secondary
Nystagmus (Sec)

Pa —- —§$— S §- — — - 1
Da — -—_— $s — — — es
Br —- —- —-  —

Do >- CO Cr Ore rr
Ch —_ —_ 30.6. 428 283 27.1
Ro —_ _ 12.7 413 514 45.4
Ve _ —_— 48.8 46.1 402 381
Te _— 11.4 23.0 Wl (3841 35.9
Dt 818 40.2 44.4 588 401 35.7
Sa 213 —_— — 32.2 829 288
Pa —_— —_— 51.7 419 39.2 358
Dy —_— — 50.4 50.0 33.7 3819
M= * * 46.8 413 875 © 87.2
Beats of Primary Nystagmus After End of Stimulus
Pa 13.0 13.0 19.5 36.5 39.0 27.5
Da 10.0 25.0 66.5 825 940 81.0
Br _ 27.0 115 29.0 33.0 29.5
Do 9.0 13.0 39.5, 47.0 425 39.0
Ch 15 29.5, 47.0 455 425 37.0
Ro 85 24.5, 43.0 50.5 70.0 62.5
Ve 45, 30.0 41.0 44.0 37.0. 82.5
Te —_— 23.0 58.0 46.0 515 38.5
Dt 12.0 39.5 55.5 63.5 595 | 55.5
Sa 20.0 315 78.5 73.0 52.5 540
Pz 4.0 12.0 84.5 34.0 285 24.0
Dy 15.0 20.5 47.0 510 46.5 |= 48.5
M>= 10.4 24.0 44.7 50.2 49.7 43.7

*Too few scores on which to base a mean.



ACKNOWLEDGMENTS

Dr. Guedry is Chief of Experimental Psychology, Research Department,
USN Aerospace Medical Institute, Pensacola, Florida; Dr. Collins is Chief,
Psychology Laboratory, Civil Aeromedical Institute.

This study was conducted at the Civil Aeromedical Institute in Okla-
homa City with the technical assistance of Billy P. Updegraff, Ruth Ann
Mertens, and Kathryn Quattlebaum.

Qualified requesters may obtain Aviation Medical Reports from Defense Documentation
Center. The general public may purchase from Clearinghouse for Federal Scientific
and Technical Information, U.S. Dept. of Commerce, Springfield, Va. 22151


100

50

40

30

ChE ACTIVITY, % OF CONTROL

20

° 6 x 10°° Molar
60 x 10-8 Molar

—o 100x1I0-® Molar

© 200xI0°9 Molar

«ex 600x107° Molar

1 ! ! it 1 it ! ! J

30 60 90 120 150 180 210 240 270
MINUTES AFTER PARAOXON ADDITION

Ficvxe 2. Inhibition of cholinesterase in whole human blood following the addition of paraoxon. The numbers at
right indicate the final concentration in 99.8% blood Substrate conc, was 20 mM in reservoir,

5



study using their procedure of measuring acetyl-
cholinesterase by constant pH-titration. This
method, although it possesses the advantage of
low dilution of the sample, requires a longer
analysis time; a skilled operator is able to per-
form about 40 analyses per day. Holtzman or
Charles River albino rats weighing 150-170 gm
were injected (ip.) once daily with Disyston,
1 mg/kg. After 10 or 24 days of this treatment
these rats and control rats that received daily
injections of solvent, were beheaded at 24 hrs
after the last injection. Brains were removed
immediately and homogenized in cold Ringers
solution; approximately 1% dilutions (precisely
known) were analyzed by the titration method
and approximately 42 dilutions (precisely
known) were assayed by the automated technique.
Data from each poisoned rat were compared with
cholinesterase (ChE) values for control animals
killed at the same time. The cholinesterase activ-
ity for each rat is presented in Table I as percent
inhibition, based on control values; this is neces-
sary to compare data derived by the two methods
because the substrate acetylcholine is hydrolyzed
by rat brain cholinesterase approximately three

Tassie I, Inhibition of Brain ChE in Chronically
Poisoned Rats.
% Inhibition
Dayt Rat
\Constant pH Titration|Autoanalyzer Method
a4 79.1
Ht 761 75.0
10
78.6 75.7
cm 8138 769
BA 785
H 79.7 82.7
1718 74.7
24
st 169
Cc 79.6 8L7
79.6 813

+ Daily Injection of Disyston, 1 MG/KG For 10 or 24 Days
* Holtzman ‘Mean Difference = 0.38
+* Charles River t = 0.368
p =>0.5
times faster than the thiol analog. Statistical
analysis of the data supported the hypothesis
that identical evaluations of cholinesterase in-
hibition were obtained by both methods. There-
fore, the automated technique would be useful in

the assessment of organophosphorus poisoning
in large numbers of samples.

V. Stability of Inhibition in Paraoxon-
Poisoned Blood

Figure 2 demonstrates the usefulness of the auto-

mated procedure in generating families of curves

when accurate timing is required.

In this experiment paraoxon was added to
whole blood via microsyringe to the final con-
centrations indicated. Because sampling occured
evéry 2 minutes the concentrations were prepared
at 2 minute intervals to ensure equal incubation
times. To evaluate the precision of the sampler
cam we recorded the sampling times throughout
the 240 minute experiment; the sampling interval
never deviated by more than .04 minute through-
out the experiment.

The data depicted in Figure 2 indicate that
the cholinesterases in whole blood react slowly
with paraoxon, equilibrium being reached at about
60 minutes; this rate shold be taken into account
when blood cholinesterase activity is to be used
as an index of poisoning.

There is some indication that inhibition was
reversed after about 75 minutes when paraoxon
concentration was 60 x 10° molar. This effect
is consistent with the presence of a paraoxonase
in blood as suggested by Augustinsson and Heim-
burger (9) and this is supported by data obtained
in another experiment. Whole blood, plasma,
and saline-washed erythrocytes were incubated
for 100 minutes, long enough to reach equilbrium,
with paraoxon at various concentrations. The
results, presented in Figure 3, indicate that
greater concentrations of paraoxon were required
to inhibit the erythocyte enzyme when plasma
was also present than when the washed cells were
exposed to the inhibitor.

This effect of plasma could be due to the pres-
ence of a paraoxon-hydrolyzing enzyme or to
paraoxon-reactive sites which are not associated
with cholinesterase activity. In either case, if the
plasma factor which modifies the inhibition of
erythrocyte cholinesterase is variable between in-
dividuals, the cholinesterase activity of blood
cannot be used as an indicator of blood paraoxon
concentration. On the other hand, the extreme
sensitivity of washed cells to paraoxon might
be useful in measuring the concentration of this
poison in protein-free solutions. We are pres-
ently studying the variability of the plasma fac-


an arousal task®, while in the last two trials, the
Key Press (KP) technique of estimating sub-
jective velocity was used to maintain alertness.
With the KP technique, the subjects attempted
to signal successive angular displacements of 90°.
Table 5 contains an outline of the test procedures
for this reliability check. Nystagmus data for
acceleration and deceleration and for the two
tasks showed no evidence of a fall-off in response
during stimulation, and the primary-to-secondary
nystagmus transition points were almost identical
to those obtained under the first set of conditions.

The data were thus combined and curves depict-
ing horizontal and vertical nystagmus were
plotted in Figure 7. As in the first group of
human subjects, no clear evidence for a decline
of response during the stimulus is evident. How-
ever, the vertical nystagmus time-plot does show
considerable irregularity as compared with hori-
zontal nystagmus data. Thus, the differences
between man and cat that were obtained from
the first groups of subjects were confirmed with
different subjects and under conditions in which
the arousal variable was manipulated.

Taxus 5. Order of stimulus presentation for human subjects used in the reliability check.
Arousal of subjects was controlled by Mental Arithmetic and Key Press tasks. All trials
comprised accelerations and decelerations of 4°/sec? for 36 sec separated by 2 min of constant

velocity.
Subjects Rotation Mental Arithmetic Key Press
Male Female Direction Trial 1 Trial 2 Trial 3 Trial 4
A Ww cw Lateral Vertical Vertical Lateral
B x CCW Lateral Vertical Vertical Lateral
Cc Y cw Vertical Lateral Lateral Vertical
D “a cCcw Vertical Lateral Lateral Vertical

It has been reported that vestibular nystagmus
rises and declines, like the subjective reaction,
during constant angular acceleration.%:77%7
However, Guedry & Lauver demonstrated that
the nystagmic reaction in man did not decline
during prolonged constant angular acceleration
if the subjects were required to signal estimates
of angular displacement. Occasionally, however,
a subject would yield a rise and decline in the
nystagmus response similar to the subjective re-
sponses in earlier experiments (see Figure 4 in
Guedry & Lauver). To check the possibility
that arousal accounted for the variety of find-
ings, Collins & Guedry* required subjects, during
prolonged angular accelerations, to perform
mental tasks, which would maintain mental ac-
tivity independent of the subjective perception
of rotation. Subjects were required to make
arithmetic computations throughout the vestibu-
lar stimulation and post-stimulation _ periods.
Results showed again that nystagmus first in-
creased and then remained constant during con-
stant angular acceleration. Following the termi-
nation of stimulation, nystagmus decayed about
as expected from the “torsion pendulum” theory",
although rates of decay were not calculated.

The same subjects, when allowed to relax, occa-
sionally showed a rise and decline of nystagmus
during constant stimulation, and a rapid decay
of response on termination of the stimulus. The
present experiments confirm the fact that nystag-
mus does not decline during prolonged angular

acceleration in alert human subjects, although

such declines appear to occur in cats.

In cats, time to onset of secondary nystagmus
was inversely related to duration of the stimulus.
The earlier onset of the secondary reaction can-
not be attributed to loss of arousal. This result
strongly suggests that the decline in primary
nystagmus during and after the longer stimuli
resulted from a counteracting process which re-
duced the intensity and duration of the primary
nystagmus and then became evident as an early
secondary nystagmus. Data from humans have
shown that as the duration of a constant angular
acceleration is increased beyond certain time
limits, the duration of the subjective after-
responses becomes shorter and shorter.!#44 _ Nys-
tagmic reactions in cats showed similar effects
and, in these respects, more closely resembled
the subjective reactions of man than they did the
nystagmus of man.



tor in man and experimental animals in order
to evaluate its importance in the estimation of
the magnitude of exposure to organophosphorus
poisons.

VI. Stability of Inhibition by Carbamates

It is well known that the inhibition of blood
cholinesterase by carbamate inhibitors may be
partially reversed by dilution of the sample”.
As the method of Levine, Scheidt and Nelson
necessitates about a 1/15 dilution, we designed an
experiment to evaluate the effects of dilution on
the inhibition of whole blood by 1-naphthyl1-N-
methyl carbamate (Sevin). Three concentrations
each of Sevin and paraoxon were made up with
whole blood; after 60 minutes the carbamate-
poisoned samples were diluted with 1% Triton-X
in TRIS buffer and the mixture was immediately
taken up by the sampler. Each dilution was
subsequently sampled every 8 minutes for 80
minutes. After 100 minutes of incubation the
paraoxon-poisoned specimens were analyzed in the
same way. Figure 4 presents the results in terms
of percent of unpoisoned control which were
analyzed concurrently.

Obviously, serious errors in the measurement
of carbamate inhibition could occur if samples
are not analyzed immediately upon dilution.
This error could be minimized by sampling un-
diluted blood into a system which employs a
much shorter incubation time, and we are pres-
ently investigating this possibility, but there
seems to be no way to reduce the dilution which
occurs in the apparatus when the sample is mixed
with substrate, buffer, etc.; this amounts to an
additional sample dilution of approximately 1/14.
The constant pH titration method, however, im-
posed only a slight additional dilution (a total
dilution of 1/4.5 for the entire assay) due to the
addition of NaOH solution during titration of
the released acetic acid. We attempted to evalu-
ate the effects of the “built-in” dilution in the
automated thiocholinesterase assay by comparing
our results on eserine- and Sevin-inhibited sam-
ples to those obtained with the constant pH
titrator; we are grateful to Mr. Leonard Ryan
for data obtained by this latter method. This
comparison is presented in Table II. One sample
of heparinized human blood was divided into 9
parts and 3 concentrations each of paraoxon,
Seven and eserine were made up. After allowing
30 minutes for the two carbamates and 100 min-

utes for paraoxon to equilibrate, the cells and
plasma were separated and diluted in Ringer-
Triton-X solution and analyzed immediately by
both techniques. The data obtained from each
poisoned sample were compared with those from
non-poisoned blood assayed by the same pro-
cedures.

Taste II, COMPARISON OF INHIBITION DATA OB-
TAINED BY THE AUTOANALYZER (AUTO) AND
THE CONSTANT pH TITRATION (pH) TECHNIQUES

Chb ACTIVITY—
PERCENT OF CONTROL
RBC PLASMA
AUTO pH AUTO pH
PARAOXON
150x10-°M * 71 a 47 36
300x10-°M * 42 42 18 14
450x10-°M * 18 18 6 6
SEVIN
0.5x10-5M. 66t 60" git 3t
1x105M_ ot 49 50 84 83
1x104M* 22 13 30 29
ESERINE
2,61x10-9M f 95 90 95 88
13x10°M * 8 8 4 4
2.6x10-°M * 5 8 2 2

* NO, NURTHER DILUTION FOR AUTOANALYSIS OF

§ ADDITIONAL i4s°DYLOTON Pow AUPOANALYSIS

In Table II those columns marked with an
asterisk present data which were obtained when
no further dilution of the sample took place
prior to automated analysis; other columns de-
note an additional 1% or 1/8 dilution over that
used in the constant pH method. These data
indicate that results obtained by the autoanalyzer
technique are comparable to those obtained by
the titrator method despite the fact that a much
greater dilution of the sample is inherent in the
former technique. It therefore seems likely that
the automated dialysis method developed by Le-
vine, Scheidt and Nelson would be useful in the
detection of carbamate poisoning provided that
samples are diluted just prior to analysis, or
better, that a much shorter incubation time be
employed so that prior sample dilution becomes
unnecessary.



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PROBLEMS IN AERIAL APPLICATION

Detection of Mild Poisoning by Organophosphorus Pesticides
Using an Automated Method for Cholinesterase Activity

Patsy R. Fowler, M.S.
Jess M. McKenzie, Ph.D.

Approved by Released by
J. Roserr Druuz, M.D. P. V. Stren, M.D.
Curer, Civ, AEROMEDICAL Feprrat Air Surcron
InstiTUTE
April 1967

FEDERAL AVIATION ADMINISTRATION
Office of Aviation Medicine



34, Harpy, L. H., Ranp, R., & Rrrrcer, M. C. Test for
the detection and analysis of color blindness, III.
Rabkin test. J. Opt. Soe. Amer., 35 :481-491, 1945.

From an examination of the second edition of the
Rabkin test the authors concluded that, properly
administered, the test affords a good device for
sereening the color defective from the color normal
if 75 is taken as the critica’ verformance score. The
test taken as a whole affords an excellent means of
classifying red-green dichromats into the two groups:
protanopic and deuteranopic; it also provides for
classification of red-green anomalous trichromats
into two groups: deuteranomalous and protanoma-
lous. The test is not adequate to differentiate be-
tween anomalous trichromasy and dichromasy.

35. Harpy, L. H., Ranp, G., & Rivrrer, M. C. The
H-R-R polychromatic plates. I. A test for the
detection, classification, and estimation of the
degree of defective color vision. A.M.A. Arch.
Ophthal, 51 :216-228, 1954.

The paper described the construction, administra-
tion, validation, and reliability of the H-R-R poly-
chromatic plates.

36. Harpy, L. H., Rano, G., & Rirrier, M. ©. - The
H-R-R polychromatic plates. II. Comparison of
qualitative and quantitative classifications by
H-R-R plates and other tests, A.J£A. Arch.
Ophthal., 52 :358-368, 1954.

This paper presented further validation and relia-
bility information concerning the H-R-R polychro-
matic plates. It presented a comparison of the
qualitative and quantitative diagnoses yielded by
the H-R-R plates with performances on other tests
of color vision.

37. Harpy, L. H., Rap, G., & Rirrier, M. C. H-R-R
polychromatie plates. J. Opt. Soc. Amer., 44:509—
523, 1954.

This paper presented approximately the same infor-
mation as the two previous papers.

38. Htoxr, R. & Nakamura, Y. Hioki’s polarization
anomaloscope. Amer. J. Ophthal., 40 :550-562, 1955.

This paper described construction of a polarization
version of the Nagel anomaloscope.

39. Homperc, L. The distribution and reliability of
certain color vision data as measured by the
Pickford-Nicolson anomaloscope, Psychol. Res.
Bull., 3 :7pp., 1963.

This paper presented the standardization data for
the Pickford-Nicolson anomaloscope. The instrument
was found to be a valuable and sensitive tool for
color vision testing as well as for psychophysical
investigation.

40. Hoocerweipe, J. Considerations about the accept
ability of mild color defective trichromats in
flying personnel. Aeromed. Acta, 7:17-23, 1959,
1960.

The author recommended testing flying personnel
with the Hardy-Rand-Rittler plates. He also rec-
ommended passing those people who make no mis-
takes in the medium and strong plates. The author
suggested that pilots with mildly anomalous color
vision do not pose any danger.

41. Josu1, V. G. Brightness contrast as a source of
error in the Ishihara test for color blindness.
Brit. J. Physiol. Opt., 18 :239-242, 1961.

Plates of the Ishihara test for color blindness were
photographed in black and white by so modifying
the technique of exposure that the color sensitivity
of the film emulsion was made uniformly constant
to all spectral colors. The older the edition, the
greater the visibility of the numerals in the photo-
graphs. Factors of “color contrast” and “brightness
contrast” appeared to be of comparative importance
in the Ishihara test.

42, Katavisto, M. Pseudo-isochromatic plates and arti-
ficial light. Acta Ophthal. (Kobenhavn), 39:377-
390, 1961.

Thirty persons with normal color vision and 50
with defective color vision were tested with Bostrém
UU, Ishihara, and Stilling pseudo-isochromatic plates
in daylight, and by the light of tungsten lamps and
flourescent tubes with high color temperature. Simi-
lar results were obtained with the Bostrém plates
with each of these three sources of light, and with
the Ishihara plates in daylight and in the light of
flourescent tubes. The results obtained with Stilling
plates were reliable only in daylight. ‘Thus, the
Bostrom and Ishihara plates are well suited for
tests of color vision by light of flourescent tubes,
which can be recommended as a standard illuminant
during the dark winter months.

43, Katavisto, M. — Vaiiriaistin tutkimisesta pseudo-
isokromaattisilla tauluilla, (Color sensitivity ex-
amination with pseudo-isochromatic tables). (in
Finnish) Suom. Litiiklehti, 17 121-126, 1962.

‘The principles for use of pseudo-isochromatic tables
and the reliability of obtained results were surveyed
by making comparisons between the Stilling, Bos-
trém (IIB), Ishihara, and Tokyo Medical College
tests. The latter was recommended as a rapid
screening test for mass examinations of color vision.
‘The importance of an accurate sense of color in
certain professions was stressed and, hence, it was
proposed that the testing of color vision be included
in vocational guidance.

44, KirscHen, M. The color rator: a new instrument
for the assessment of color aptitude in industry.
Amer. J. Optom., 36 :137-143, 1959.

An instrument was described for the determination
of color aptitude or color discrimination with the
red and green portions of the spectrum. The match-
ing principle was used. An additional advantage
of this instrument was that the procedure as out-
lined was sufficiently simple for its administration
by a lay person at the employment level of industry.
Criteria for its use were proposed from a prelimi-
nary study of 21 subjects. Range of settings at
various wavelengths was adopted as principle cri-
terion for pass or fail decisions.

45. Lakowskt, R. Testing of colour vision in prospec-
tive printers’ apprentices and the problems this
presents in selection. Brit, J. Physiol. Opt.,
22 :10-82, 1965.




ad

References

|. Kortre, G. B.: J. Pharmacol. Exp. Therap., 100 :158,

1950.

. AUGUSTINSSON, K. B.: Scand. J. Clin. & Lab. Invest.,

7 :284, 1955.

. Tapacunrk, I, I.: Biochim. et Biophys. Acta, 21:58,

1956.

McOsxer, D. E., and Danuet, L. J.: Arch. Biochem.
Biophys., 79:1, 1959,

ELtman, G. L., Courtney, K, D,, Anpres, V., and

Fratuerstone, R. M.: Biochem. Pharmacol. 7:88,
1961.

6. Levins, J. B., Scemr, R. A. and Netson, D. A.:

Automation in Analytical Chemistry. Mediad Inc.,

New York, 1966, p. 582.

Report of the Commission on Enzymes of the Inter-

national Union of Biochemistry. Pergamon Press,

New York, 1961, p. 8.

8. Garry, P. J., and Rours, J. I.: Clin. Chem., 11:91,
1965.

9. Aveustinsson, K. B., and Hermnurcer, G.: Acta
Chem. Scand., 8 :1588, 1954.

10. Krayer, O., Gotpstern, A., and Pracure, F. L.: J.
Pharmacol., 80:8, 1944.

a



pressure was decreased to equivalents of 14,000,
18,000, 25,000, 30,000 and 34,000 feet, leveling off
at each altitude with the subject engaged in
three-minute intervals of rest and light exercise
at each altitude (Figure 6).

The bicycle ergometer was operated by each
subject at 45 rpm and a workload'setting of 45

&

DESCEND FOR
EAR CHECK
‘AND DON MASK

oe
a

8

25

AIR
BREATHING
BASELINES

R= RESTING
E + EXERCISE

ALTITUDE / THOUSANDS OF FEET
nr
3

A ee
05 10 15 20 25 30 35 40 45 SO 55 60 65 75
ELAPSED TIME IN MINUTES

Ficure 6.—Altitude chamber flight profile.

OXYGEN SUPPLY
CONSTANT FLOW

REGULATOR SCOTT]
No, 25620-3

ALTITUDE CHAMBER WALL

On
QD has
ort
SCOTT MASK
OXYGEN HOSE ASSEMBLY
OUTLETS

SCOTT MASK
INDICATOR NO, 8540

D
[_[iie3s a

Crwe IN
ORIFICE

a)

watts, approximately equivalent to walking at
a rate of 3.0-3.4 miles per hour on level terrain.

Oxygen flow provided to the mask is a func-
tion of the altitude response of the regulator
which produces an increase in line pressure to
fixed calibrated plug-in orifices incorporated in
the mask hose. As altitude is increased, pres-
sure and resultant flow to the mask are increased,

Oxygen flow, as provided by the regulator
and orifices furnished with the mask, was de-
termined by separately exposing the regulator
to the same altitudes as the human subjects and
recording the flow under standard conditions
outside the chamber as shown in Figure 7. The
capacity of the regulator to maintain pressure
and resultant flow with a single as well as eight
orifices connected to the system, was also de-
determined (Figures 8 and 9). Representative
oxygen flow rates during the human subject tests
with a single outlet in use are shown in the first

portions of Tables 4 and 5.

E PRESSURE
ADJUSTING
E CLAMP

E BROOKS
ROTAMETER
E 0-10 L/min,

TYPE 6-II1
viencuny)

SERIAL
10660-1385/i
MANOMETER

a aoe

Figure 7—Diagram of test method for determining flow characteristics of the automatic constant flow regulator

and orifices.

5.

‘Regulator and outlets installed inside chamber and exposed to altitude.





Scoring. Slow-phase displacement of the eyes
was scored by measuring the peak to base-line
distance for each beat of nystagmus and sum-
ming these values for 3-sec intervals. Time
measurements were also made from the end of
each stimulus (a) to the end of the primary
response and (b) to the start of the secondary
nystagmus. The number of beats of primary
nystagmus which followed stimulus termination
was tabulated.

IV. Results and Discussion

A. Cats

Measures of both response time and the number
of beats of primary nystagmus following stimu-
lus termination appear in Table 2. Post-stimulus
responses of greatest duration and magnitude
occurred when stimulus durations were between
3 and 15 sec with the maximum post-stimulus
primary response occurring, in general, with
stimuli of 9 sec duration.

907 PRIMARY NYSTAGMUS
80 ca
r * o—+ 30 SEC
a X——x 21 SEC
7OF 1 \ 15 SEC
—~—: \ ‘. 9 SEC
60F o—s 3 SEC
a \
a \ s+ 1.2 SEC
& 50r . STIMULUS DURATION
o \
i} x
40F
g |¥ \
2 oly \
30F e
< \ \
2 . \ ° x
2 20F /N 4 \ \
oN \ \ \
@ 10 |” ‘ % ° \ ‘
x \ N \ N \
a ~ ~“ \ .
' er ee >> —e
z 3 6 9 I2 15 18 21 24 27 30 33 36 39 42 45 48 51 54
a
307 = SECONDARY NYSTAGMUS 2
y STIMULUS: 4°/SEC
>
| x" oS AGE FOR 12 CATS
2p AVERAGE FO
_ ‘x.
Rept NERS =
Hor wa i RR
tag =}
N, _——
aN - SS eae

9 12 15 18 21

TIME

24 27 30 33 36 39 42 45 48 SI

54

IN SECONDS

Freure 1. Time-course plots of slow-phase eye displacement per 3-sec interval for 12 cats exposed to 6 stimulus

durations of 4°/sec’ angular accelerations.
begin to decline during the stimulus.
ulus termination,

2

For the 21 and 30 sec durations, responses reach a peak and
For the two shortest durations, the peak response occurs after stim-
Peak magnitude of the secondary reactions appears related to stimulus duration,


46.

a7.

48,

49,

‘The performance of the printers’ apprentices (boys
between the ages 14-17) on all the color vision
tests used in this study was different ‘from that of
the control group. This difference appeared as dif-
ferences in the most frequent type of response ac-
cepted by the members of each of the two popula-
tions, and as differences in the variability of such
performances, This was best seen in the anomalo-
scope, where there was a difference in terms of
mid-matching points accepted by the two groups
and this applied also to variability of their matching
ranges. There was a decidedly higher incidence of
subjects with minor color deficiencies in the experi-
mental group. There were twice as many deutera-
nopes as found in other studies, The author sug-
gested that perhaps ages 14 through 16 are the best
times to test color vision for vocational purposes,
for at this stage any latent weakness will be indi-
cated.

Lryxsz, A. The Farnsworth panel D-15 test. Amer.
J. Ophthal., 62 :27-87, 1966.

This paper discussed the principles and uses of the

Farnsworth panel D-15 test. Extending its use for

diagnosing tetartan and achromatic defects was also

discussed,

Mamma, A, Awaya, S., & Tanape, S. Evaluation
on Ishihara plates (numeral and winding-line
plates), H-R-R plates, and T.M.C. plates for
screening tests, (in Japanese) Jap J. Clin, Oph-
thal., 18 :493-496, 1964.

The authors reported that the Ishihara is an ex-

cellent test for screening, while the H-R-R plates

proved unsatisfactory for this purpose.

McCurtocH, ©, Turnour, N. C., & Smuey, J. R.
A field study of Hardy-Rand-Rittler color vision
plate test. Amer. J. Ophthal., 48 :124-129, 1959,

This paper compared the H-R-R color vision test

with the American Optical Company pseudo-isochro-

matic plate test used by the RCAF and with the

RCAF lantern, The authors suggested that with

the Hardy-Rand-Rittler test a simplified form can

be used and subjects may record their own responses.

Mounteanv, M. Examination of the colour sense in
the navy. The chromatoscope. Rev. Int. Serv.
Santé. Armées., 38 :361-368, 1965.

‘This paper described a form of color lantern and its

use in the testing of color vision,

Naxagma, A. Icnrkawa, H., Nakagawa, 0, Ma-
sia, A, & Watanane, M. Ishihara test in color
vision defects. Studies on a statistical method
for evaluation of the screening efficiency of several
plates, Amer. J. Ophthal. 49 921-929, 1960.

A set of Ishihara test plates (25 plates from the

thirteenth edition) was used for the screening of

color vision defects in 3,033 school children aged
six to ten years, along with three other plates for
tritanopes and anomaloscopic examination for de-
fectives picked up by the screening. Using the
number of misread plates as criterion, this set of

Ishihara test plates could separate red-green defec-

tives very clearly from normals. Analysis of the

distribution of misreadings by statistical methods

51.

. PERDRIEL, G.

was presented. The Poisson law can be used for

the approximation of the observed distribution, and

efficiency in error of screening can be estimated on
this basis.

Pécnovux, R., Ressfauir, J., Derayorre, M., & Ray-
monv, R. ftude d’une batterie a’épreuves pour la
aétection des anomalies de Ja vision des coujeurs
dans les centres de seléction. Bull. Cent. Btude
Rech. Psychotech., 6 :171-182, 1957.

This paper compared Beyne’s lantern with the ortho-

rater and the Ishihara test. The author recom-

mended that all subjects be examined with the ortho-
rater, Those who obtain scores of eight or more
on the scale of ten should be considered normal.

Those who score seven or less should undergo the

simplified Ishihara test. Those who score exactly

eight in the Ishihara test should be considered
normal, Those whose score on the Ishihara is less
than or equal to seven should be examined by

Beyne’s lantern.

L'examen de la vision des couleurs en
pratique courante, Annee Ther. Clin. Ophthal.,
11 :221-237, 1960.

This article surveyed existing color vision tests. It

has brief descriptions of the tests but no compari-

sons were made among them,

Perpriet, G. Le test de Farnsworth 100 hue. Ann.
Oculist. (Paris), 195 :120-130, 1962.

This paper described the principles and uses of the

Farnsworth 100 Hue test.

| Peters, G. The new Dvorine color perception test.

Optom. Wkly., 45 :1801-1803, 1954.
This paper presented some normative data for the
second edition of the Dvorine color perception test.

55. Peters, G. Diagnostic sensitivity of color perception

BT.

. Perers, G.

tests. Optom. Wkly., 46 :136-137, 1955.

This paper compared the second edition of the

Dvyorine color perception test with the American

Optical Company color perception test. The author

concluded that the second edition of the Dvorine

test was a more sensitive diagnostic instrument for
the detection of color defects than was the American

Optical Company color test (18 plate selection).

A color-blindness test for use in voca-
tional guidance. Optom. Wkly., 48 1171-1178, 1957.

A quantitative Classification table was presented as

an aid in the interpretation of the Dvorine color

perception test. This provides a classification as to
degree of defect, the percentages of color blindness
that may be found in the general population for
each degree of defect, and an estimate of the voca-
tional limitation resulting from such defects.

PicxrorD, R, W. ‘Test for color blindness.
Med. Bull. , 1953.

This is a review of the tenth «dition of the Ishihara

test. The author suggested that the tenth edition

was less reliable than the eighth, and that the ninth
edition fell between them.

Pickrorp, R. W. A practical anomaloscope for test-
ing color vision and color blindness, Brit. J.
Physiol. Opt., 14 :2-26, 1957.

A simple filter anomaloscope for testing red-green

Brit,



ADAPTATION TO VESTIBULAR DISORIENTATION

VI. Eye-Movement and Subjective Turning Responses to
Varied Durations of Angular Acceleration

I. Introduction

Ocular nystagmic responses elicited by angular
acceleration have been found to be different in
cat and in man.é With prolonged stimuli (36
sec), a rise and decline of nystagmus during
stimulation was obtained from cats for both
Jateral- and vertical-canal stimulation. Human
subjects did ‘not exhibit a comparable decline
during prolonged stimulation. Nystagmic reac-
tions of the cat thus resembled the subjective
(rather than the nystagmic) reactions of human
subjects,2#.2.19.20

At least part of the difference noted above in
regard to primary nystagmic reactions appears
related to the prominent secondary nystagmus
which characterizes responses of the cat to angu-
lar accelerations. Secondary nystagmus is op-
posite in direction to the primary response, and
it may reflect a process which develops during,
and opposes continuation of, the primary re-
action.

The present investigation represents an exten-
sion of the earlier study.? A range of stimulus
durations was used to clarify relations between
stimulus duration, the rate of decline of primary
nystagmus, and the intensity of secondary nys-
tagmus, and to compare further vestibular pro-
cesses in cat and man.

IL. Methodology

A. Cats

Apparatus. Rotational stimulation was pro-
vided in a light-proof room with the Huffman
Rotation Device.’ Angular accelerations and
decelerations were 4°/sec? separated by 54 sec of
constant velocity. Animals were tested in pairs
(with their heads at the center of rotation) by
means of a set of tiers.

Restraint. Restraint was effected by the method
of Henriksson, Fernandez, and Kohut*® and in
the manner described elsewhere.°

Recording. An Oftner Type R Dynograph re-
corded horizontal components of eye movements
from needle electrodes inserted by the outer
canthi. A 3-sec time constant was used in
amplification.

B. Human Subjects

Apparatus. A Stille-Werner RS-8 rotator was
programmed to provide accelerations and de-
celerations of 4°/sec* separated by 2 min of con-
stant velocity.

Recording. An Offner Type T polygraph (time
constant: 8 sec) recorded horizontal components
of eye movements from surface electrodes taped
by the outer canthi.

III. Procedure

Each of 12 cats and 12 human subjects re-
ceived 6 rotatory trials comprising 4°/sec? ac-
celerations and decelerations for 1.2, 3, 9, 15, 21,
and 30 sec. Rotation was always counterclock-
wise and the order of presentation of the stimu-
lus durations was counterbalanced among pairs
of subjects as indicated in Table 1.

Taste 1. Order of presentation of stimulus durations
(in seconds). Durations varied from 1.2 to 30 sec.
All angular accelerations were 4°/sec* and rotation

was always counterclockwise. Only the lateral
canals were stimulated.

Human Trials
Subjects Cats 1 2 8 4 5 6

Pz&Ch 108&109 12 30 9.0 150 210 300
Dy&Do 110&111 3.0 9.0 150 210 300 12
Sa&Br 112&118 9.0 15.0 210 3800 12 30
Dt&Da 114&115 15.0 210 300 12 30 90
Te& Ro 116&117 21.0 300 12 30 90 150
Ve& Pa 118&119 300 12 30 90 150 210

None of the subjects had been used in previous
vestibular experiments. Human subjects (6 men
and 6 women) were instructed to signal onset.
and cessation of their rotatory experiences by
means of a signal key.





ie}

800
o WHOLE BLOOD

«# RBC Corrected to
Whole Blood

° PLASMA Values

700

a

= 600
°

©

~

> 500
Ee

2

2
400
>

EF

2

= 300
Oo

< a
ud

& 200

100
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fe | i { i 1 J
10) 100 200 300 400 500 600

PARAOXON CONCENTRATION, NANOMOLAR

racRe 8. Protection by plasma of erythrocyte cholinesterase in the presence of paraoxon. Whole blood, plasma
and washed erythrocytes from human blood incubated with paraoxon for 100 min, Erythrocytes washed and re-
constituted to whole blood volumes with saline. Plasma ChE activities corrected to whole blood values using
hematocrits. Note that plasma and RBC value may be added to obtain whole blood ChE activity in the un-
poisoned samples, but not in paraoxon-exposed groups.



80 36 SEC STIMULUS

70

AVERAGE FOR 8 CATS

50

40

30

ro

°

3

20

30

80

8.4 SEC STIMULUS

"| |

———e HORIZONTAL NYSTAGMUS

SLOW- PHASE NYSTAGMUS (DEGREES)

..

© VERTICAL NYSTAGMUS

TIME IN SECONDS

Ficure 2. Time-course plots of slow-phase eye displacement in 3-sec intervals for 8 cats. Arrows indicate termina-

tion of acceleration. Points above the zero line represent primary nystagmus; points below the zeroline repre-
sent secondary nystagmus. In the upper graph, a clear peaking and decline of nystagmus during the accelera-
tion is evident for responses to both lateral- and yertical-canal stimulation. In the lower graph (84 sec
stimulus), 3-sec intervals were marked off from the end of the stimulus (thus the first “3-sec” interval repre-
sents response during only 2.4 sec of stimulus). Total output of both primary and secondary nystagmus is
consistently greater for the lateral canals,



PERFORMANCE CHARACTERISTICS OF CONSTANT-FLOW
PHASE DILUTION OXYGEN MASK DESIGNS FOR GENERAL AVIATION

I. Introduction.

Recent technological advances in general avia-
tion have resulted in the development of aircraft
with increased altitude capability and service
ceilings. On January 11, 1966, a stock model
single-engine Cessna Turbo-System Centurion
set a new world altitude record of 39,334 feet for
light aircraft.

Oxygen in aviation was first used by French
aeronauts and scientists in the famous flight of
the Zenith, a balloon ascension which on April
15, 1875, attained an altitude in excess of 8600
meters (28,000 feet). Oxygen was breathed
from goatskin bags through a scented wash bot-
tle and a small rubber tube held in the mouth.
Unfortunately, in attempting to conserve their
supply of oxygen, these high altitude pioneers
became severely hypoxic and lost consciousness.
Of the three members aboard the Zenith flight,
only one survived. Up until the development of
the constant flow BLB mask just prior to World
War II, the mouth-held tube or pipestem was
still the most common method of administering
oxygen in aviation, Not until late in World
War II and thereafter were the demand and
pressure demand oxygen systems developed.

Constant-flow rebreather type oxygen masks
similar in concept to the BLB are most fre-
quently used in general aviation, due to their
relatively low cost and oxygen economy afforded
at lower altitudes. One basic disadvantage of
constant flow oxygen masks is their inherent
inability automatically to adjust to the require-
ments of the user as influenced by his emotional
or physical activity.

Dilution of oxygen in constant flow masks is
generally afforded by orifices or dilution ports
of a predetermined size which allow a varying
amount of air to enter the mask, depending upon
the oxygen flowing to the mask and the respira-
tory activity of the individual wearing the
mask. Portions of the exhaled gas, higher in

oxygen concentration than air, are returned to
the rebreather reservoir bag for re-use. Other
portions are vented out through the dilution
ports, maintaining carbon dioxide at an accept-
able level. At higher altitudes, it becomes in-
creasingly difficult to control and assure high
concentrations of oxygen with these types of
constant flow or economizer masks unless the
mask is flooded with’ oxygen at uneconomical
flow rates. With the advent in 1955 of require-
ments for short duration emergency protection
of commercial jet passengers to altitudes of
40,000 feet following the loss of cabin pressuri-
zation, the continuous flow phase dilution mask
was developed.*+ This oxygen mask, which
conforms to the National Aerospace Standard
NAS 1179, does not employ rebreathing and is
so designed that 100% oxygen is delivered to the
lungs at the beginning of inspiration® This is
most advantageous since toward the end of in-
spiration air is admitted by a valve only after
the oxygen in the reservoir is depleted. Air in-
troduced by the valve may penetrate the mask
and physiological dead space only. This portion
of the tidal volume is the first to be expelled
upon initiation of exhalation, Air under these
circumstances never reaches the alveoli of the
lungs and is therefore physiologically ineffective.

The continuous flow oxygen masks described
in this report and designed primarily for general
aviation are outgrowths of these developments
and incorporate features of rebreathing and
phase dilution masks.

IL Methods.

Two prototypes of new experimental rebreath-
ing—phase dilution masks manufactured by the
Scott Aviation Corporation were evaluated at
altitude on resting and active subjects, These
tests were designed to evaluate the physiological
adequacy and efficiency of the mask as well as
the oxygen system as an entity, For comparative



REFERENCES

I. Bert, P. Barometric Pressure, Researches in Eaperi-
mental Physiology (translated from the French by
M. A. Hitchcock and F. A. Hitchcock). College Book
Co., Columbus, Ohio, 1943.

Drayton, F. A. and Cartson, L. D, Evaluation of
Prototype Passenger Orygen Mask Assemblies, Report
No. D6-1954, Boeing Airplane Co., Transport Div.,
Feb. 9, 1959,

Qualification Test Report, Passenger Oxygen Mask,
QTR 59-6. Aro Equipment of California, Los Angeles,
California, June 24, 1959.

2.

3.

12

4,

. BALKE,

Koester, N, BE. and Enrmann, E, Emergency Oxygen
Mask Development and Tests. Scott Engineering
Report No, 554, Nov. 30, 1956,

. National Aerospace Standard, NAS-1179, Aerospace

Industries Assn. of Amer.
B. Continuous Determination of Nitrogen
Concentrations During the Respiratory Cycle. Pro-
Ject Number 21-1201-0014, Report No. 5, USAF
School of Aviation Medicine, June 1954,

Lurr, U. ©. Evaluation of the K-S Disposable Oxy-
gen Mask. Special Project, USAF School of Aviation
Medicine, Jan. 1951.


a

9

10.

11.

REFERENCES

Apzian, E. D., 1943: Discharges from vestibular re-
ceptors in the cat. J. Physiol., 101, 389.

AscHan, G. and Beresrepr, M., 1955: The genesis of
secondary nystagmus induced by vestibular stimuli.
Acta Soe. Med. Upsal., 60, 113.

. Carpet, K. L., 1966: Determination of physical con-

stants of the semicircular canals from measurement
of single neural unit activity under constant angular
acceleration. In Second Symposium on the Role of
the Vestibular Organs in the Exploration of Space.
NASA Report SP-115, 229.

. Coriins, W. E., 1964: Primary, secondary, and caloric

nystagmus of the cat following habituation to rota-
tion. J. comp. physiol. Psychol., 57, 417.

. Cortins, W. E., and Guepry, F. H., 1962: Arousal

effects and nystagmus during prolonged constant an-
gular acceleration. Acta oto-laryng. (Stockh.), 54,
349,

. Cortins, W. E., and Guepry, F. E., 1967: Duration

of angular acceleration and ocular nystagmus from
cat and man. I. Responses from the lateral and the
vertical canals to two stimulus durations, Acta oto-
laryng. (Stockh.), in press.

Corzins, W. E., and Hurrman, H. W., 1964: Design
and performance characteristics of a mechanically
driven vestibular stimulator. OAM Report No. 64-15,
Oklahoma City, Oklahoma,

Cortins, W. E., and Uppeorarr, B. P., 1966: A com-
parison of nystagmus habituation in the cat and the
dog. Acta oto-laryng. (Stockh.), 62, 19.
Dopez, R., 1923: Habituation to rotation.
Psychol., 6, 1.

Ex, J., Jonaxers, L. B. W., and Kurs, J.A.J., 1960:
On the effect of continuous acceleration. Acta oto-
laryng. (Stockh.), 51, 416.

Groen, J. J., 1960: Problems of the semicircular canal
from a mechanico-physiological point of view. Acta
oto-laryng., Supl. 163, (Stockh.) 59.

J. exp.

12. Guepry, F. E., and Ceran, 8. J., 1959: Derivation of
“subjective velocity” from angular displacement esti-
mates made during prolonged angular accelerations:
Adaptation effects. U. 8. Army Med. Res. Lab. Re-
port No. 376, Fort Knox, Kentucky.

Guepry, F. E., Cramer, R. L., and Koruna, W. P.,
1958: Experiments on the rate of development and
the rate of recovery of apparent adaptation effects
in the vestibular system. U. 8. Army Med, Res. Lab.
Report No. 338, Fort Knox, Kentucky.

14. Guepry, F, E., and Lavuver, L. §, 1961: Vestibular
nystagmus during constant angular acceleration. J.
appl. Physiol., 16, 215.

Henrixsson, N, G., Fernanpez, C., and Konur, R. L,
1961: The caloric test in the cat. Acta oto-laryng.
(Stockh.), 58, 21.

Lowenstein, O., 1956: Comparative physiology of the
otolith organs. Brit. Med. Bull., 12, 110.

MELvitt Jones, G., 1967: On the dependence of oculo-
motor response upon the neural response of the vesti-
bular system. Paper presented at Third Symposium
on the Role of Vestibular Organs in Space Explora-
tion, Pensacola, Florida (Jan, 24-26, 1967).

Metvitt Jones, G., and Spetts, K. E,, 1963: A theo-
retical and comparative study of the functional de-
pendence of the semicircular canal upon its physical
dimensions. Proc. Roy. Soc, B, 157, 403.
Mrrrermarer, R., and Rossserc, G., 1956: Vesti-
bularesuntersuchungen mit schwellennaken Beschleue-

13.

1b.

16.

1.

18.

19.

gungsreizen, Arch. Ohren-Nasen-U. Kehlkopfh., 168,
313.
20, Montanpon, A., and Fumeavx, J., 1957: Valeur dia-

gnostique comparative des nystagmus per- et post-
rotatoires 4 l’épreuve giratoire liminaire. Prac. oto-
rhino-laryng., 19, 556,

21, vAN Eomonp, A. A. J., Groen, J. J., and JonaxEEs,
L. B. W., 1949: The mechanics of the semicircular
canal, J. Physiol., 110, 1.







B

wp

s

ca

10.

11.

REFERENCES

. Buys, E., 1924: Contribution a Yetude du nystagmus

oculaire de la rotation chez homme, Rev. Oto-neuro-
Ocul., 2, 641.

. Carpet, K. L., 1966: Determination of physical con-

stants of the semicircular canals from measurement
of single neural unit activity under constant angular
acceleration. In Second Symposium on the Role of
the Vestibular Organs in the Exploration of Space.
NASA Report SP-115, 229-236.

Cortins, W. E., 1962: Effects of mental set upon
vestibular nystagmus. J. exp. Psychol., 63, 191.
Cortins, W. E., 1964: Primary, secondary, and
caloric nystagmus of the cat following habituation
to rotation. J. comp. physiol. Psychol., 57, 417.
Cottins, W. E., and Guepry, F, E., 1962: Arousal
effects and nystagmus during prolonged constant
angular acceleration. Acta oto-laryng. (Stockh.),
54, 349,

}. Coutins, W. E., and HurrMan, H. W., 1964: Design

and performance characteristics of a mechanically
driven vestibular stimulator. OAM Report No. 64-15.
Oklahoma City, Oklahoma.

Coutts, W. E., and Uppsorarr, B. P., 1966: A com-
parison of ‘nystagmus habituation in the cat and
the dog. Acta oto-laryng. (Stockh.), 62, 19.
Crampton, G. H., and Brown, J. H., 1964: Repeated
vertical semicircular canal ‘stimulation does not
habituate horizontal nystagmus in cat. Acta oto-
laryng. (Stockh), 58, 441,

Dover, R., 1928: Habituation to rotation. J. exp.
Psychol, 6, 1.

Ex, J., Jonoxers, I. B. W., and Kruw, J. A. J.,
1960: On the effect of continuous acceleration, Acta
oto-laryng. (Stockh.), 51, 416.

Groen, J. J., 1960: Problems of the semicircular
canal from a’ mechanico-physiological point of view.
Acta oto-laryng., (Stockh.), Suppl. 163, 59.

14

12. Guepry, F. E., and BrserMan, N., 1957: Apparent
adaptation effects in vestibular reactions. U. 8.
Army Med. Res. Lab., Report No, 293, Fort Knox.
Kentucky.

13. Guepry, F. H., and Ceran, S. J., 1959: Derivation
of “subjective velocity” from angular displacement
estimates made during prolonged angular accelera-
tions: Adaptation effects. U. 8S. Army Med. Res.
Lab. Report No. 376, Fort Knox, Kentucky.

14. Guepry, F, E., Cramer, R. L., and Kortra, W. P.,
1956: Experiments on the rate of development and
the rate of recovery of apparent adaptation effects
in the vestibular system. U. S. Army Med. Res.
Lav. Report No, 338, Fort Knox, Kentucky.

15. Guepry, F, E., and Lavver, L, 8., 1961: Vestibular
nystagmus during constant angular acceleration.
J. appl. Physiol., 16, 215.

16. Henriksson, N. G., FERNANDEZ, C., and Kouur, R.
1961: The caloric test in the cat. Acta oto-laryng.
(Stockh.), 53, 21.

17. Hoop, J. D., 1961: The neuro-physiological signifi-
cance of cupular adaptation and its bearing upon
Ewald’s second law. Acta oto-laryng. (Stockh.),
Suppl. 159, 50.

18, Mrrrermaier, R., and Rossperc, G., 1956: Vestibu-
laresuntersuchungen mit schwellennaken Beschleue-
gungsrelzen, Arch. Ohren-Nasen-U. Kehlkopfh., 168,

3.

19. Montanpon, A. and FumeEavuz, J., 1957: Valeur
Diagnostique comparative des nystagmus peret post-
rotatories a’ l’epreuve girotoire liminaire. Prac.
oto-rhino-laryng., 19, 55%

20. Mowrer, O. H., 1985: The nystagmic response of
the pigeon to constant angular acceleration at liminal
and supraliminal intensities. J. comp. Psychol., 19,
177.

21. Wenpr, G. R., 1950: Some characteristics of vesti
bular eye movements, In Psychophysiological Fac-
tors in Spatial Orientation, US ONR Symposium,
U. 8. Naval Air Station, Pensacola, Florida.


Qualified requestors may obtain Aviation Medical Reports from Defense Documentation
Center. The general public may purchase from Clearinghouse for Federal Scientific
and Technical Information, U.S. Dept. of Commerce, Springfield, Va. 22151




75 Hydrolyzed standard
with substrate

Hydrolyzed standard
without substrate ,

60F O Glutathione
with substrate J

O Glutathione ‘
50 F without substrate J

OPTICAL DENSITY

fe) | J J
(0) | 2 3

CONCENTRATION (MILLIMOLAR) IN THE SAMPLE

Fracre 1, Fyaluation of reduced glutathione and hydrolyzed substrate (acetylthiocholine) as standards. Lines
marked [] and O indicate results with glutathione when substrate is pumped concurrently and when 0.9% NaCl
is substituted. The line marked A represents data obtained from hydrolyzed acetylthiocholine with and without
the presence of unhydrolyzed substrate; in this case all points (2 for each condition) fell within the area of
the triangle.


23.

24,

25.

26.

27.

28,

tests, which would be more reliable in its pass-fail
criteria and less dependent upon the training and
personal interpretation of the examiner. A model
of the proposed Navy Lantern, called the New Lon-
don Prototype Model, was tested on over 2,000 indi-
viduals and compared with other standard tests for
color vision.

Frexket, A, B, Differential diagnosis of color vision.
(in Russian) Dokl. Akad. Nauk. SSSR., 100 :57-60,
1955.

This paper compared the performance of color de-

fectives on the Rabkin plates and on the Rautian

anomaloscope in distinguishing color signal lights.

The paper concluded that Rayleigh equations are an

inadequate index of color defect.

Frexxet, A. B, An experiment in the application
of Yustova’s tables for investigation of color
vision, (in Russian) Biofizika, 1:708-712, 1956,

This paper described the Yustova plates for color

vision testing and their use.

Frey, R. G. Welche pseudoisochromatischen Tafeln
sind fiir die Praxis am besten geeignet? Albrecht
wv. Graefes Arch. Ophthal., 160 :301-320, 1958.

This paper compared the Bostrdm, Bostrém-Kugel-

berg, H-R-R, Ishihara, Rabkin, and Stilling color

plate tests.

Frey, R. G. Zur Vereinfachung der Farbensinn-
priifung. Wien. Klin. Wschr., 73 :852-854, 1961.
In order to reduce the time spent in testing color
vision and, at the same time, to make reliable tests,
it is necessary to combine pseudo-isochromatic plates
with high selectivity and usefulness, The author
recommended use of the following four plates:
Farnsworth’s tritan plate, Bostrém’s plate 10, Bos-

trom-Kugelberg’s plate R, and Rabkin’s plate 14,

Frey, R. G. Die Trennscharfe einiger pseudo-
isochromatischer Tafelproben. Albrecht v. Graefes
Arch. Ophthal., 165 :20-80, 1962.

This paper compared the pseudoisochromatie plate

tests of Dvorine, Velhagen, and Polack. The author

recommended the Dvorine without changes. He
concluded that the Velhagen test becomes more use-
ful when restricted to the 17 plates of raised selec-

tivity. He concluded that a selection of only 14

plates from the Polack test is useful.

Frey, R. G. Zur Differentialdiagnose der angebore-
nen Farbensinnstérungen mit pseudoisochroma-
tischen Tafeln. Ophthalmologica (Basel), 145 :34—
48, 1963.

A collection of pseudo-isochromatic plates was ex-

amined to determine their differential diagnostic

possibilities and the results were compared with
anomaloscope findings. It was possible to a certain
extent to determine whether a protan or deutan
disturbance existed, ‘The Rabkin tables produced

a correct qualitative diagnosis in 97.4% of the cases,

Dvorine in 94%, Hardy-Rand-Rittler in 90.1%, Po-

lack in $8%, Ishihara in 82.7% and the Tokyo

Medical College color vision’ test in 65.2%. The

quantitative diagnosis in all cases varied consider-

ably from the findings of the anomaloscope. More

31.

32.

33.

particularly those cases which would be classified
as “mild” by the Hardy-Rand-Rittler tables or by
the Tokyo Medical College test should probably be
classified as anomalous trichromats. From exami-
nations made with the TMC no certain conclusions
can be drawn as to the nature and extent of the
color disturbance,

Frey, R. G. Zur Wahl der geeigneten Beleuchtung
fiir die Farbensinnprufung mit pseudoisochroma-
tischen Tafeln. Wien. Klin. Wschr., 76:170-172,
1964,

This paper enumerated the illumination and color

temperature of the illuminants required by various

pseudo-isochromatic plates. The author emphasized
the need for holding illumination constant in the
testing of subjects.

. Frey, R. G. Erfahrungen mit der 7. Auflage der

polychromatischen ‘Tafeln J. B, Rabkins. (Ex-
periences with the seventh edition of the J. B.
Rabkin polychromatic tables). Alin. Mbl. Augen-
heilk, 145 :97-106, 1964,

‘The seventh edition of the “Polychromatic charts”
of Rabkin were used to test two groups of 170
persons each, who had been examined with the
anomaloscope and classified accordingly into one
group with normal color sense and another with
defective color sense. In an abridged form, this
collection can be recommended for the rapid and
reliable detection of persons with defective color
vision, A positive differential diagnosis cannot be
established by means of these charts. The charts
for the examination of the color vision of children,
charts which were enclosed for the first time in
this edition, need to be improved.

GatiacHer, J. R. & Gattacuer, C. D. Color vision
sereening of preschool and first grade children.
Arch. Ophthal., 72 :200-211, 1964,

Observations relevant to the color vision testing of
preschool and first grade children were reported.
About 3% of each of the two groups studied ap-
peared to have a color vision defect of sufficient
degree to constitute a practical handicap in cor-
rectly discriminating colors. A simple screening
method for detecting significant degrees of color
vision deficiency in preschool and first grade chil-
dren was described. It is based on a selected num-
ber of AO H-R-R plates.

Gotpstein, A. G. & Brooxs, R. A red-green color
vision test employing transparencies. Percept.
Motor Skills, 11 :229-230, 1960.

A red-green color vision test employing transparen-
cles was described and data for 18 subjects were
presented. The authors recommended continuing
research to determine whether correctly exposed
transparencies may be employed for group color
vision testing.

Harner, R. A decade of research in color blind-
ness. Psychol. Newsltr., N.Y.U., 8:128-148, 1957.
This is a survey article reviewing the literature on
color defects from 1946 to 1955, inclusive, All as-
pects of color defect, including color testing, were

reviewed.



DIAGNOSTIC TESTS OF COLOR DEFECTIVE VISION
Annotated Bibliography, 1956-1966

1, Battey, R. W. Color vision deficiencies in army
fliers. USAARU Report No. 65-2. April, 1965,
Fort Rucker, Alabama.

This paper deals with a review of some color tests

and a testing procedure employed to determine the

number of color anomalous fliers in army aviation.

Data collected indicate that the color requirements

may be unnecessary and that a new approach is

overdue.

Baxer, H, D. Single-variable anomaloscope matches
during recovery from artificial red blindness, J.
Opt. Soc, Amer., 56 :686-689, 1966.

An anomaloscope was designed so that full amounts

of its red and green primaries could be adjusted to

match yellow.

8, Baron, J., Capau, A, & PanMenrien-Beroux, M.
Application du test de Farnsworth 100 hue dans
VYexamen de la vision colorée. Le Presse Med.,
64 :561-562, 1956.

The Farnsworth 100 Hue test was examined and
compared with other tests. The authors concluded
that the Farnsworth 100 Hue test was good for
diagnosing the anomalies of color vision and also
for diagnosing difficulties in color discrimination,

. Betcuer, S, J., GREENSHIELDs, K. W., & WricHT,
W. D. Color vision survey using the Ishihara,
Dvorine, Bostrém, Bostrém-Kugelberg, and Ameri-
can-Optical  Hardy-Rand-Rittler tests. Brit. J.
Ophthal., 42 :355-359, 1958.

Five hundred subjects were tested with five different
sets of pseudo-isochromatic plates. The tests were
compared for division of subjects between normal
and defective and for screening efficiency of each
plate.

. Boynton, R. M. & WaGNER, M, Two-color threshold
as a test of color vision. J. Opt. Soc. Amer,
51 :429-440, 1961.

The two-color threshold is obtained by finding the
Just visible luminance of a test flash of one color
seen against the background of another color, An
examination of green-on-red thresholds plotted
against red-on-green thresholds reveals a separation
of normal subjects from the color defective. Within
the color defective group, the test seems to provide
a quantitative assessment of the degree of color
defect.

6. Bunnnam, R. W. & Crark, J. R, A color memory

test. J. Opt. Soc. Amer., 44:658-659, 1954.
‘A test for color memory has been developed using
chips from the Farnsworth-Munsell hue series, The
observer selects from a hue circle of color samples

y

i

a

a

2

10.

the one which most resembles a test sample pre-
sented a short time before. This procedure is re-
peated for a number of test samples.

, Cameron, R. G. Rational approach to color vision

testing, Aerospace Med., 38 :51-59, 1967.

A rational approach to color vision testing demands
the elucidation of three points: whether a color
vision defect is actually present, what it is, and
whether the defect is compatible with the require-
ments of the examining service. Testing of 5141
pilot candidates indicates 5.17% defectives. This
indicates that about 2%% of the defectives were
self-climinated, and the rejection of 3.9% of all
candidates can be regarded as an average figure.
‘The paper offers a plea for uniformity of definition,
of methodology, and particularly of terminology.

. CHapants, A. A comparative study of five tests of

color vision. J. Opt. Soc. Amer., 38 :626-649, 1948.
This study compares the American Optical Company,
Ishihara, Meyrowitz, Bostrém, and Bostrém-Kugel-
berg color vision tests. ‘The author reports that
the Bostrém-Kugelberg test is the best all around
test of color deficiency evaluated in the study, The
Ishihara was next best. The author found the
Bostrom and Meyrowitz plates to be unsatisfactory.
The author reports that neither visual acuity nor
age is related to performance on the tests used in
this study.

Cuapanis, A. Diagnosing types of color deficiency
by means of pseudo-isochromatic tests. J. Opt.
Soc. Amer., 39 :242-249, 1949.

Five pseudo-isochromatic tests of color vision (the
American Optical Company, Ishihara, Meyrowitz,
Bostrém, and Bostrém-Kugelberg) were evaluated
for their ability to differentiate two kinds of color
deficient individuals. The Bostrom plates were
found to be worthless for. this purpose, the Meyro-
witz plates somewhat better, and the Ishihara plates
best. None of the plates in the other two tests was
found to be diagnostic.

Corr, B. L. Misuse of the Ishihara test for color
blindness, Brit. J. Physiol. Opt., 20 :118-118, 1968.

‘This paper examined the weaknesses of the Ishihara

test for color blindness and suggested two working

rules for its use: (1) A patient who misreads three
plates or less is almost certain to have normal color
vision, If he misreads between three and six plates,
he can be considered to be normal, provided some of
the errors are not typical of the errors that the
color defective makes, (2) No reliable quantitative
assessment of the severity of the defect can be ex-



ADAPTATION TO VESTIBULAR DISORIENTATION

V. Eye-Movement and Subjective Turning Responses to
Two Durations of Angular Acceleration

I, Introduction.

During prolonged angular acceleration, inertial
torque deflects the cupula but the deflection is
eventually balanced, primarily by the cupula’s
elastic restorative force. Assuming that cupula
displacement from its position of static equilib-
rium controls the magnitude of vestibular reac-
tions, a prolonged angular acceleration should,
according to the “Torsion-Pendulum” theory”,
yield an increasing response for about 20-30 sec;
this response level should be maintained without
decline as long as the angular acceleration con-
tinues. Several authors *°*1819 have reported
that the subjective velocity rises and declines
during prolonged angular acceleration, contrary
to theoretical expectations. Guedry & Ceran’
showed that the temporal period required for the
subjective reaction to peak (and then decline)
was about constant (27 sec) for angular accelera-
tions ranging in magnitude from 0.5 to 2°/sec?.
Subsequent experiments (Guedry & Cunat, un-
published) showed this to be true for stimuli
up to 4°/sec*.

The present experiments seek to compare cat
and man in regard to several characteristics of
the nystagmic response elicited by two durations
of a 4°/sec? angular acceleration.

Il. Methodology.
A. Cats

Apparatus. The Huffman Rotation Device®
located in a light-proof room, was used to pro-
duce acceleration programs. Animals were tested
on the rotator in pairs with their heads at the
center of rotation. One cat box was secured to
runners on the turntable and the second box was
secured to a framed tier arrangement above the
first box.’

festraint. Cats were restrained by the method
of Henriksson, Fernandez, and Kohut.* Three
or more days prior to testing, the animals were

anesthetized and holes were drilled transversely
through their canine teeth. At the same time,
fur around the ocular orbits was shaved off and
a guideline for positioning the head was drawn
with washable ink from the canthus to the tragus
on each side. For testing, each animal was
wrapped in a towel and placed in a cat box. A
strand of piano wire was inserted through the
holes in the canine teeth. The wire was held
securely and the head of the animal was posi-
tioned by means of an adjustable device on the
front of the box.

Recording. For recording horizontal compo-
nents of eye movements, needle electrodes were
inserted by the outer canthi. Vertical compo-
nents were obtained by means of surface elec-
trodes taped above and below the left eye. The
recorder was an Offner Type R Dynograph with
3-sec time constants used in amplification. Prior
to testing, animals were placed in an optokinetic
stimulator; a drum speed of 24°/sec was used
to obtain data for calibration purposes.

B. Human Subjects

Apparatus. A Stille-Werner RS-3 rotating
chair, situated in a light-proof room, provided
the acceleratory stimuli for the human subjects.

Recording. A pair of surface electrodes, taped
by the outer canthi of the eyes, detected hori-
zontal eye movements, while a second pair was
positioned above and below the left eye for the
recording of vertical eye movement. An Offner
Type T polygraph with a 3-sec time constant
was used in amplifying and recording the eye
movement signals. Eye calibrations were ob-
tained prior to each test by means of a calibra-
tion chart located on one wall of the rotation
room.

Il. Procedure.

Each of eight cats and eight human subjects
received 2 angular accelerations (for 8.4 and 36
sec) stimulating the lateral semicircular canals.



AM 67-9

PERFORMANCE CHARACTERISTICS OF CONSTANT-FLOW
PHASE DILUTION OXYGEN MASK DESIGNS FOR
GENERAL AVIATION

Ernest B. McFadden, M.S.
Hiley F. Harrison
James M. Simpson

Approved by Released by

S ir A PYS8, 4
P. V. Srecxr, “

J. Rosert Diniz, M.D.
Cmumr, Crvm Azromepicat InstiruTe Fepera Arr Surcron

May 1967

FEDERAL AVIATION ADMINISTRATION
Office of Aviation Medicine



310
300
290
280
270
260
250
240
230
220 F
210 F
200 F
190 F
180
170 F

fo)

160 F
150 F
140 F
130 F
120 F-
HOF

1 1 j
100 18 25 30 34

ALTITUDE THOUSANDS OF FEET

Fieure 10.—Comparison of calculated resting tracheal
oxygen partial pressures. Summary of data from
Tables 1, 2 and 3.

TRACHEAL OXYGEN PARTIAL PRESSURE

% DILUTION VALVE MASK
@ POROUS DILUTION PORT MASK
© OPEN DILUTION PORT MASK

oxygen partial pressures than the similar mask
equipped with open dilution ports. Had oxygen
flows been lower it is anticipated that this dif-
ference would be exaggerated. In addition, if
the tracheal oxygen partial pressure is reduced
to a point approximating 90 to 100 mm Hg,
hypoxic drive of respiration may ensue. In this
case, a vicious cycle may develop when using
constant flow diluter masks in that the mask

300 -
290 Ff
280 F
270

% DILUTION VALVE MASK
@ POROUS DILUTION PORT MASK
O OPEN DILUTION PORT MASK ~
260 +
250 +
240 +
230
220
210
200
190 £
180 + ©
170 + i
160 +
150 +
140
130 +
120 F if
lo F y
J

100 : ;
18 25 30 34

ALTITUDE THOUSANOS OF FEET.

Figure 11—Comparison of calculated tracheal oxygen
partical pressures during exercise. Broken lines and
arrows at 30,000 and 34,000 feet indicate magnitude
of depression of tracheal oxygen partial pressure
induced by high inspiratory flows characteristic of
speech (reading). Summary of data from Tables
1, 2 and 3.

TRACHEAL OXYGEN PARTIAL PRESSURE

of——0

wearer may reflexly hyperventilate. The in-
creased ventilation results in more ambient air
being drawn into the mask, diluting the oxygen,
which in turn increases hypoxia and hyperventi-
lation, continuing reduction of mask efficiency
and resulting in an increased deterioration of
the physiological condition of the mask wearer.



Plots of the complete nystagmic responses to
the 8.4 and the 36 sec stimuli appear in Figure 2.
Slow-phase output was scored by summing the
vertical displacements of beats from peak to
base-line for successive 8-sec intervals. Greater
output of primary nystagmus is evident for the
lateral canals, as compared with the vertical
canals, for both stimulus durations. For the
84 sec stimuli, primary nystagmus increased
throughout the stimulus period for both the
“horizontal” and “vertical” curves. For the 36
sec stimulus, there was a marked peaking in the
response to stimulation of the vertical canals
during the 15-18 sec interval, and a steady de-
cline of that response throughout the remainder
of the stimulus. For stimulation of the lateral
canals during the 36 sec stimulus, peaking oc-
curred in the 18-21 sec interval and was fol-
lowed by a lesser decline than that noted for the
vertical canals.

Secondary nystagmus was also plotted in
Figure 2. With only one exception (the 8.4 sec
stimulus to the vertical canals for cat No. 100),
scorable secondary nystagmus was obtained from
each cat for each stimulus condition. For both
vertical and lateral canal responses, the 36 sec
stimuli produced greater secondary responses
than did the 8.4 sec stimuli. In addition, hori-
zontal secondary nystagmus showed greater out-
put than vertical secondary nystagmus by
amounts proportional to differences in their re-
spective primary reactions. Further, the mean
peak of the secondary response occurred 21-24

sec after the end of the 8.4 and 36 sec stimuli for
horizontal nystagmus, and 15-31 sec after the 8.4
and 36 sec stimuli for vertical nystagmus.

To pursue further the relationship of secondary
to primary nystagmus and the effects of pro-
Jonged stimuli on those responses, six of the ani-
mals were given, one day later, a series of 15
trials stimulating the lateral canals with the
4°/sec? stimulus for 36 sec duration. Tracings
for trials 1, 5, 10, and 15 were scored and the
data plotted in Figure 3. With repeated stimu-
lation, a marked depression of both the primary
and secondary response curves occurred, peaking
of the response was followed by a decline in
nystagmic output during the remainder of the
stimulus, and the peaks of both primary and
secondary nystagmus shifted toward earlier oc-
currences.®

A. Human Subjects

Eight human subjects (4 males and 4 females)
were given stimulations identical to those ad-
ministered to the cats. Nystagmus data were
also scored similarly and appear in Table 3.
Some examples of nystagmus tracings are pre-
sented in Figure 4. In addition, duration of the
sensation of turning was calculated from the
end of each stimulus to the end point of the
sensation (Table 4).

In 20 of the 48 comparisons (Table 3), human
responses to the 36 sec stimulus exceeded re-
sponses to the 8.4 sec stimulus (9 of these cases
were for the “number of beats” measure) and,

Taxte 3, Measures of primary nystagmus following the termination of each rotatory stimulus for human subjects. Each
response value is a mean of responses to an acceleration and a deceleration stimulus, Stimuli were 4°/sec? for either 8.4 or

36 seconds.

Time From End of Stimulus to
End of Primary Nystagmus (Sec)

Time From End of Stimulus to
Start of Secondary Nystagmus (Sec)

Beats of Primary Nystagmus
After End of Stimulus

Lateral Vertical Lateral Vertical Lateral Vertical

Subject 8.4 36 84 36 84 36 8.4 36 8.4 36 84 36

Nu 24.7 18.9 21.1 7.6 32.9 26.5 55,2 13.4 18.5 14.5 15.0 9.0
Or 29.8 34.7 16.1 26.5 32.0 36.6 9.8 9.0 92.0 61.5 25.5 23.0
Me 32.0 25.4 16.0 14.6 38.6 32.1 24,2 16.5 25.0 24.5 13.0 9.5
Wa 42.4 33.0 8.5 10.5 48.1 38.6 13.6 14.9 23.0 32.5 5,0 10.5
Po 18.2 28.2 6.2 11.2 21.6 © 94.5 9.8 19.2 9.5 21.0 2.5 9.5
Fr 36.2 30.4 22.4 9.0 39.8 30.1 15.8 14.5 38.5 45.5 16.0 13.0
Jo 37.1 36.1 15.8 4.9 36.6 32.6 on 8.0 36.0 47.5 6.5 7.0
Ma 41.0 38.8 9.4 13.7 41.4 43.0 20.2 17.1 54.5 77.5 7.5 10.5
M= 32.7 30.1 14.4 12.3 36.4 33.0 21,2 14,1 387.1 40.6 11.4 11.5



Detection of Mild Poisoning by Organophosphorus Pesticides

Using an Automated Method for Cholinesterase Activity

I. Introduction.

In 1950 Koelle? reported ‘the use of thiolesters
of choline in the histochemical detection of
cholinesterase. Subsequently, many investigators
have described various techniques for using these
acetylcholine analogs as substrates for the quan-
titative measurement of cholinesterase in solu-
tion. Hydrolysis of acetylthiocholine has been
followed by iodometric titration’, decreased ab-
sorbance of the thiolester bond’, and by reaction
of the free SH group with nitroprussidet. By
far the most sensitive and reliable method, how-
ever, was presented by Ellman e¢ al° who
measured cholinesterase by reaction of released
thiol with 5,5’-dithiobis (2-nitrobenzoie acid)
[DTNB]. A molar extinction coefficient of
13,600 was obtained at 412 mu.

A primary disadvantage of the manual tech-
niques used for measuring the rate of hydrolysis
of acetylthiocholine in the presence of blood and
tissue homogenates is the high optical density
due to the sample; for example, varying degrees
of lipemia make it necessary to subtract a sample
blank reading (no DTNB added) from the ab-
sorbance of each test mixture when plasma
cholinesterase is measured. This disadvantage
is minimized in the automated procedure reported
in 1965 by Levine, Scheidt and Nelson’. In their
technique a dialysis module is used so that only
dialyzable substances, including unmasked thiol
groups, can diffuse into a DTNB stream and
thence into the light path of a colorimeter flow
cell.

We have used the automated technique over
the past year for the assay of cholinesterase ac-
tivity in a variety of samples including blood
and tissues of animals poisoned with organophos-
phorus and carbamate insecticides. We have
found the method to be fast and reliable, but, as
are most new methods, subject to certain pitfalls
and errors which must be either corrected or kept

in mind when the results are interpreted. In
this report these problems will be considered.

The apparatus used in these experiments was
exactly as described by Levine, Scheidt and
Nelson® except that air was pumped into the
DTNB side of the dialyzer through a .073 ID
tube rather than the size used by the above
authors. In all experiments the substrate con-
centration was 20 mM (as pumped).

II. Selection of the Sulfhydryl Standard.

Provided an adequate reaction time, almost
any non-hygroscopic thiol compound of mod-
erately high molecular weight may be used as a
standard in the manual analysis of cholinesterase
activity. However, the presence of a dialyzer
membrane in the automated method imposes ad-
ditional restrictions. For example, reduced glu-
tathione, recommended as a standard by Levine,
Scheidt and Nelson, produced an entirely differ-
ent calibration curve when the substrate was
being pumped into the system as compared to the
slope produced when saline was substituted for
acetylthiocholine solution.

The presence of this substrate produced no
effect on the calibration slope for glutathione in
the manual assay; therefore, it was concluded
that acetylthiocholine in some way augmented
the transport of glutathione across the dialysis
membrane.

Other thiol standards were made by completely
hydrolyzing acetylthiocholine perchlorate or io-
dide in weak alkali and then neutralizing with
HCl. The data presented in Figure 1 indicate
that identical slopes were obtained regardless of
the presence of (unhydrolyzed) substrate. As
thiocholine is the precise molecule to be measured
in this method it seems most appropriate to use
hydrolyzed substrate as a standard. This prepa-
ration may be diluted to appropriate concentra-
tions and stored at -20°C for months without
loss of sulfhydryl groups. A simple check for
complete hydrolysis is to compare the solution



representation of movement, due to central and
peripheral differences, will differ slightly in
different animals.

The functional significance of the secondary
process is not established. Some pathological
conditions undoubtedly yield a central imbalance
of spontaneous input from the two ears, and the
“secondary process” may serve to readjust the
point of homeostatic balance. Some complex
motions of the head and body may terminate
with minor residual cupula deflections, and this
could require minor shifts in the point of bal-
ance between the two ears, which would be ac-
complished too slowly by the elasticity of the
cupula. Tolerance to an increased level of ves-
tibular stimulation encountered in land, sea, and
air travel may require a suppression at some
level of vestibular inflow, and it is possible that
this secondary process serves this function. It
has been shown that standard test stimuli ad-
ministered after an angular acceleration are
influenced in proportion to the duration of the
preceding angular acceleration, and it may be
assumed that this finding is another manifesta-
tion of the “secondary process.” Moreover, with
repetitive angular accelerations, the peaks of
both primary and secondary nystagmus in cats

diminish and shift toward earlier occurrences.*°
This suggests that the secondary process en-
croaches more and more upon the primary reac-
tion and thus limits the magnitude and duration
of the primary reaction with repetitive stimula-
tion. In humans, there are large individual
differences in secondary nystagmus. If the sec-
ondary reaction is a manifestation of an adap-
tive process which serves to limit the primary
reaction, it may prove to be an indicator, among
people with comparable histories of motion ex-
posure, of individual differences in ability to
habituate to repetitive vestibular stimulation.

VI. Summary

A direct relationship between duration of ac-
celeration and (a) decline of response during
acceleration, (b) rate of decline of response after
acceleration, and (c) magnitude of secondary
reaction, is regarded as an indication of a cen-
tral process which limits a prolonged vestibular
primary reaction. The process is manifested by
its influence on relatively basic reflex reactions
(nystagmus) in the cat, and is more prominently
manifested in man by its influence on sensory
perception.


SLOW-PHASE NYSTAGMUS (DEGREES)

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36 SEC STIMULUS

F ° ‘e AVERAGE FOR 10
/ \ ° D-AMPHETAMINE CATS

e ° @—@ HORIZONTAL NYSTAGMUS
r fr \ O——O VERTICAL NYSTAGMUS
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9 18 27 36 45 54 63 72 8! 90 99 108
TIME IN SECONDS

Figure 6. Time-course plots of primary and secondary nystagmus in 3-sec intervals for cats treated with d-amphet-

amine,
sec stimulus (4°/sec*) is evident for both lateral- and vertical-canal stimulation (compare with Figure 2).

Similar to results obtained from undrugged cats, a peaking and decline of the response during the 36

12


ACKNOWLEDGEMENTS

The authors are grateful to Dr. W. Stavinoha for his collaboration on
some of the experiments described in this paper and to Miss Betty Gatliff
for her illustrations. We also wish to thank Mr. William E. Geyer for photo-
graphic work.

Qualified requestors may obtain Aviation Medical Reports from Defense Documentation
Center. The general public may purchase from Clearinghouse for Federal Scientific and
Technical Information, U.S. Dept. of Commerce, Springfield, Va. 22151


61.

62.

64,

. Scumipt, I.

and yellow-blue color vision was described. The
technique for using the anomaloscope and norms
for normal color vision and for color defective vision
were provided.

. Prckrorp, R. W. & Laxowski, R. The Pickford-

Nicolson anomaloscope for testing and measuring
colour sensitivity and colour blindness, and other
tests and experiments. Brit. J. Physiol. Opt.,
17:181-150, 1960.
An anomaloscope based on a simple colorimeter
was described that permits red-green and blue-yellow
tests.

. Rano, G. & Rirrier, M. C. An evaluation of the

AO H-R-R pseudo-isochromatic plates. A test for
detecting, classifying, and estimating the degree
of defective color vision. A.3f.A. Arch. Ophthal.,
56 :736-742, 1956.

The paper evaluated the AO H-R-R rseudo-isochro-

matic plates and compared them with the prototype

I-R-R tests.

Ravtian, G, A new anomaloscope.
Biofizika, 2 :734~-T42, 1957.

This paper described an anomaloscope that permits

three tests of color discrimination in addition to

the usual Rayleigh anomaloscope test.

Riv, R. Le probleme de la perception des signaux
colorés et du Daltonisme dans la marine. Rev.
Med. Nav., 11:7-85, 1956.

This paper presented the design for the Beyne

chromoptemetric lantern. This lantern was designed

to present lights equivalent to the color signal lights
used in aviation, in the navy, or on railroads.

Stimuli are variable in brightness, size, and dura-

tion, The lantern was compared with the lantern

currently in use in the French Navy.

Rorn, A. Le test 28 hue selon Farnsworth. Bull.
Soe. Ophthal. Fr, 66 :231-238, 1966.

This paper described a test using 28 hues taken

from the Farnsworth-Munsell 100 Hue test and pre-

sented together as in the Farnsworth Dichotomous

(Panel D-15) test. It was claimed that the test

can isolate protans, deutans, tritans, tetartans, and

achromats with scotopic vision.

Sawa, J. Note on the color vision tests with pseudo-
isochromatic test plates. (in Japanese) Jap. J.
Olin, Ophthal., 18 :1207-1211, 1964.

This paper described several pseudo-isochromatic

test plates and assessed their individual charac-

teristics. The author concluded that the Ishihara
was the most reliable for screening subjects. He
reported that other charts, especially the H-R-R and
the TMC, gave equivocal results in borderline cases.

For classifying color deficient subjects, the author

found the H-R-R charts superior to the TMC charts.

He found none of the available charts satisfactory

for the determination of the severity of the color

deficiency.

(in Russian)

Comparative evaluation of the New
London Navy lantern for testing color perception.
Project No. 21-29-009. August, 1951. USAF Sch.
Aviat. Med., Randolph Field, Texas.

The New London Navy lantern test for color per-

66.

67.

68,

ception was evaluated. The author recommended

that subjects be adapted to room illumination for

one-half hour before testing and that the number
of retests in any one series be fixed.

Scumiwr, I. Some problems related to testing color
vision with the Nagel anomaloscope. J. Opt. Soc.
Amer., 45 514-522, 1955.

Topics dealt with include: elimination of training

effects and determination of the total number of

readings required to detect minimum practical dif-
ferences between individuals; application and fre-
quency distribution of the anomalous quotient;

determination of the normal matching range of mix-

tures and of comparison yellow; and test-retest re-

liability of the Nagel anomaloscope,

Seeretct, E, R. An evaluation of the validity and
reliability of the AOC 15-plate pseudo-isochromatic
test in routine testing. Amer. J. Optom., 41:371-
381, 1964,

This paper compared the classification of 409 airmen
by the AOC 15-plate test with the classification de-
termined by the anomaloscope. The author con-
cluded that the AOC 15-plate test lacked the neces-
sary validity and reliability to make it possible to
obtain proper color vision classification by a single
administration of the test under mass testing
conditions.

Seerett, E, R. A comparison of the AOC and the
Dvorine pseudo-isochromatic tests in color vision
testing. Amer. J. Optom., 42 :250-255, 1965.

Color vision classifications of 210 airmen were de-

termined by the AOC and the Dvorine tests as well

as by the anomaloscope. Test results indicated the

Dvorine test was a superior dichotomous test when

compared to the AOC test. The contention that the

Dvorine test might be used quantitatively did not

seem to be supported by the data.

. Sexr, R., Outs, Y., Tasret, K., Kurata, K.,, & Fu-

xkupa, T. The results on color vision tests by the
panel D-15, (in Japanese) Acta Soc. Ophthal.
Jap., 68 1312-1328, 1964.

This paper reported the study of color vision testing
using the panel D-15 on normal subjects, congenital
and acquired color deficient subjects. Many con-
genital deuteranomalous and protanomalous subjects
passed the test with no errors, Many acquired color
deficient subjects were classified tritan.

Stoan, L. L, Evaluation of the To<yo Medical Col-
lege color vision test. Amer. J. Onhthal., 52 :650-
659, 1961.

The Tokyo Medical College color vision test was

described and evaluated by comparisons with the

Ishihara test, twelfth edition, and a special group

of 16 plates. The TMC test agreed, with one ex-

ception, with a classification determined by the 31

plates of the two other tests.

. Stoan, L, L, & Haset, A. Tests for color deficiency

based on the pseudo-isochromatic principle. A
comparative study of several new tests. A.M.A.
Arch. Ophthal., 55 :229-239, 1956,

This paper compared the Ishihara, Dvorine, and

AO H-R-R tests, All tests detected the great ma-


1007 PRIMARY menews

8° SEC

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SEC

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Pe STIMULUS DURATION
2

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3 6 9 12 1S 18 21 24 27 30 33 36 39 42 45 46 SI 54 57 60 63 66 69 72 75 78 BI 84 B87 90 93 96

20 SECONDARY NYSTAGMUS. STIMULUS: 4°/ SECT

-— kaye
a Rare cees ee eee SS one eral
3 6 9 12 IS 18 21 24 27 30 33 36 39 4245 48 5! 54 57 60 63 66 69 72 7H 78 BI 84 87 90 93 96 99 102 0S
TIME IN SECONDS

Ficure 2. Time-course plots of slow-phase displacement per 8-sec interval for 12 human subjects exposed to 6
stimulus durations of 4°/sec* angular accelerations.

dent for any duration (compare with Figure 1).
tions occurs after stimulus termination.

No decline of nystagmus during stimulation is evi-

Note that the peak response for the three shortest dura-
No secondary responses were evident for the 1.2 and 3 sec stimuli

and not all subjects showed secondary nystagmus for the longer stimuli.

The slow-phase velocity of primary and sec-
ondary nystagmic responses was plotted for each
of the 6 stimulus durations (Figure 1). For
the 21 and 30 sec stimuli, there was a slight de-
cline in response during constant angular ac-
celeration, Consistent with data from cats in
the earlier experiment,’ it appears that the nys-
tagmic response reaches maximum intensity be-
tween 15 and 20 sec and declines after this, even
though the stimulus is of constant magnitude
and direction.

The peak magnitude of secondary nystagmus
appears directly related to the duration of the
angular acceleration. Secondary responses were
obtained from all but one cat for the 6 stimulus-
duration conditions; the exception (cat 112)
gave no secondary nystagmus following the 1.2
second stimulus.

B. Human Subjects

Figure 2 shows little or no decline in human
nystagmus during constant angular acceleration

irrespective of stimulus duration. This is con-
sistent with human results of earlier studies,>***
but it is in contrast with results from cats in
which nystagmus declined after about 20 sec of
constant angular acceleration.

With brief stimuli (1.2 sec and 8 sec), it ap-
pears that in both man and cat the slow-phase
velocity of nystagmus continues to increase
(“overshoots”) after the stimulus terminates
(Figures 1 and 2), whereas, with prolonged
stimuli, slow-phase velocity of nystagmus de-
clines immediately after (in humans) or before
(in cats) the stimulus terminates (Figure 1).

As stimulus duration is increased up to about
15 seconds, the duration of the post-stimulus
primary nystagmus increases. With longer
stimuli, the duration of the post-stimulus pri-
mary response declines. In this respect human
primary nystagmus corresponds fairly well in
its temporal characteristics with the human sub-
jective response. This is shown in Figure 3


FOREWORD

This annotated bibliography of recent literature on diagnostic tests for
color defect is presented as a scientific service of the Civil Aeromedical Insti-
tute. The aims of the publication are: (a) to provide interested researchers
with source material and (b) to provide medical examiners with material
relevant to the diagnosis of color defect.

In achieving these aims, bibliographic listings such as the present one
are necessarily limited in scope. However the survey is not limited to the
years listed. Papers from years prior to 1956 concerning tests that are cur-
rently available commercially have been included and one reference is in-
cluded from 1967. No attempt is made to evaluate the scientific worth of a
given article.

References 23, 24, and 83 have recently been translated. Copies of the
translations of these papers only may be obtained by writing to: Medical
Librarian, HQ-640, Federal Aviation Administration, Washington, D.C.
20553. Please provide the librarian with the complete reference information.



AM 67-7

ADAPTATION TO VESTIBULAR DISORIENTATION

VI. Eye-Movement and Subjective Turning Responses to
Varied Durations of Angular Acceleration

Fred E. Guedry, Jr., Ph.D.
William E. Collins, Ph.D.

Approved by Released by
J. Roserr Dux, M.D. P. V. Srecen, M.D.
Cuter, Crvr, AEROMEDICAL Feperan Air Surazon
Insrrrvte
May 1967

FEDERAL AVIATION ADMINISTRATION
Office of Aviation Medicine



AM 67-6

ADAPTATION TO VESTIBULAR DISORIENTATION

V. Eye-Movement and Subjective Turning Responses to

Two Durations of Angular Acceleration

William E. Collins, Ph.D.
Fred E. Guedry, Jr., Ph.D.

Approved by Released by
J. Ropert Diiiz, M.D. P. V. Srecer, M.D.
Curer, Cryin AEROMEDICAL Fevers Ar Surgeon
Instrrure
May 1967

FEDERAL AVIATION ADMINISTRATION
Office of Aviation Medicine



Taste 4. Oxygen flow furnished by the Scott automatic constant flow regulator No.
25620-3 as measured at Normal Temperature Pressure Dry (NTPD) 22°C, 760 + 0.5 mm
He, using the orifice supplied with the new prototype version of the Scott Sky Mask. ‘This
mask incorporates a porous dilution valve. Automatic flow by increased pressure was
activated by exposing the regulator to the indicated altitudes and measured as shown in
Figure Seven. One outlet was used and the supply pressure maintained at 335 psi.

Barometric Line Flow Calculated
Altitude (Feet) Pressure Pressure © L/Min NTPD Flow L/Min BTPS.
mm. Hg. p. si.
0 760 40 0.00
8,000 565 42 Less than 1.00
18, 000 380 58 2.05 4.93
25,000 282 7 3.02 10.28
30, 000 226 74 3.63 16, 23
34,000 188 78 3.95 22, 44

Same orifice and conditions as above, but with seven additional Scott Sky Masks plugged
into the system.

0 760 41 0.00
8,000 565 42 Less than 1.00
18,000 380 58 1.98 4.77
25,000 282 70 2,92 9.94
30, 000 226 74 3.46 15.47
34,000 188 78 3.82 21.70

Taste 5. Oxygen flow furnished by the Scott automatic constant flow regulator No.
25620-3 as measured at Normal Temperature Pressure Dry (NTPD) 22°, 760 + 0.5 mm Hg,
using the orifice supplied with the prototype Scott mask. This mask incorporates a mask-
mounted microphone and a phase dilution valve. Automatic flow by increased pressure was
activated by exposing the regulator to the indicated altitude and measured as shown in
Figure Seven. One outlet used and the supply pressure maintained at 335 psi.

Barometric Line Flow Calculated
Altitude (Feet) Pressure Pressure L[Min NTPD Flow L/Min BTPS
mm. Hg, p. 8.4.
0 760 41
8,000 565 44 Less than 1.00

18, 000 380 58 2.15 5.17

25,000 282 70 3.09 10,51

30, 000 226 1 3.67 16.41

34,000 188 79 4.05 23.01

Same orifice and conditions as above, but with seven additional Scott Sky Masks plugged
into the system.

0 760 40
8,000 565 43 Less than 1.00
18, 000 380 58 2.07 4.98
25,000 282 71 3.00 10.21
30, 000 226 75 3.54 15.83
34,000 188 79 3.92 22.27

i



72.

4,

77.

78,

. Vies, LL

jority of those with deficient color perception for

red and green, Each of these tests, however, occa-

sionally failed to detect mild degrees of red-green
deficiency, Misclassification of normal subjects as
color deficient was more likely to occur with the

AO H-R-R screening plates than with either the

Ishihara or the Dvorine screening tests.

Srams, A. Controversial results in examinations of
the colour sense by employment of customary
methods. Klin. Mbl. Augenheilk, 147 :261-264, 1965,

When color testing was done with the Stilling-

Velhagen tables, the florcontrast and the anomalo-

Scope controversial results were obtained, Relevant

factors were mentioned.

. Torrey, H. Sight testing for the merchant navy.

Brit, J. Physiol. Opt., 16 :36-46, 1959.

This paper described a lantern test for color vision
and its use in the screening of applicants for seaman.
Tsursumr, S.A new color vision test. (in Japa-

nese) J. Clin, Ophthal., 18 :605~610, 1964.

An attempt was made to convert normal color vision
into artificial color defective states corresponding
to protanomaly, deuteranomaly, and tritanomaly by
wearing cyan, magenta, or yellow filters respectively.
‘The ability for color discrimination was tested under
these states; it was found that the chromatic dis-
crimination pattern for red-purple, purple, and blue-
purple plates could serve as a guide in determining
the kind and degree of color anomaly.

» Umazune, K., Sekt, R., and Osr, S. Trial manufac-

ture of new colour vision test plates. Report 1.
(in Japanese) Acta Soe. Ophthal, Jap., 58 :732-735,
1954,

‘This is a report of the test manufacture of the color

plates for the Tokyo Medical College color test.

A clinical evaluation of color testing
and color perception, Amer. J. Optom., 43 582-592,
1966.

This paper discussed the use of several color tests

for detecting color defects among school children.

Watts, G. How good is the H-R-R test for color
blindness? Amer, J. Optom., 86:169-198, 1959.

‘This is a highly critical review of the AO H-R-R

test. The author reported that as a normal-abnormal

sereening device, the test was perhaps as good as
the Ishihara and the Dvorine. The author reported
that the test made 18% incorrect red-green diagnoses,

He concluded that the test is an adequate normal-

abnormal screen; he recommended, for serious work,

the construction of a simple and inexpensive ano-
maloscope.

Watraven, P. L. & Leeszex, H. J. Recognition of
color code by normals and by color defectives at
several illumination levels. An evaluation study
of the H-R-R plates. Amer. J. Optom., 87 :82-92,
1960. .

This paper reported the number of errors in color

code readings as a function of illumination for sub-

jects grouped according to classification on the

H-R-R color plates. For all groups, the number of

mistakes decreased s illumination increased. At

all illuminations there were more mistakes the more

79,

sl.

82.

. YosHrHara, M.

severe the defect according to the H-R-R plates,

except at the two highest illuminations where the

normals and those with mild defects made equal
numbers of mistakes.

Watraven, P. L., Leeseex, HW. J. & Bouman, M, A.
ISCC color aptitude test—The interpretation of
some testing results. Report No. WW1956-10.
Instituut voor Zintuigfysiologie—R.V.O.-T.N.O. Au-
gust, 1956,

This paper compared the scores of forty-eight nor-

mals and fifty-three color deficient subjects on the

Color Aptitude test. The results indicate many

color defectives with scores as high as those ob-

tained by normals. The authors, therefore, ques-
tioned the value of the CAT as a test for color
discriminating ability.

. Wittts, M. P. & FarnswortH, D, Comparative

evaluation of anomaloscopes. BuMed Project NM
003 041.2601. Med. Res., Lab. Rpt. No, 190, 18
August, 1952. U.S. Navy Submarine Base, New
London, Connecticut.

This study examined six anomaloscozes. It at-
tempted to discover whether one type of instrument
was better than another, and to determine the rela-
tion of anomaloscope scores to scores from other
color vision tests. A combination score was pro-
posed which reduces range and deviation to one
figure and which gives an estimate of degree of
color deficiency. This scoring method can be used
with a comparative scaling technique that can be
applied to all anomaloscopes to give comparable
scores.

Wricht, W. D. Diagnostic tests for color vision.
Ann, R. Coll, Surg. 20:177-191, 1957.

‘This is a survey of various tests for color vision.
The author concluded that, except for the colori-
meter, there was no single test capable of diagnosing
all types of defects with certainty. The author
suggested that an effective battery of tests should
include one of the confusion chart tests, the Nagel
anomaloscope, and the Farnsworth-Munsell 100 Hue
test.

Yamamoro, T. A new qualitative test for color
vision. (in Japanese) J. Clin, Ophthal., 16 :383-
387, 1962.

This paper described a color test plate based on

discrimination of chroma. It is used for the classi-

fication of protanopic and deuteranopic color defec-
tive vision and for quantitatively classifying these
defects.

Study of objective measurement of
color vision (report #2). (in Japanese) Folia
Ophthal. Jap., 13 :598-610, 1962.

This paper reported measurement for color defect
based on the optokinetic nystagmus produced by
movement of a specially designed color tablet. Re-
sults indicated that the electro-nystagmograms of
color-blind subjects were irregular in type and height
of waves and in frequency and amplitude of oscilla-
tion, With this technique the author claimed suc-
cess in screening and classifying the degrees of
color blindness,



TEST INDEX

Each test is followed by the identification numbers of the reports within which the test is dis-

cussed.

Anomaloscope (unspecified )-—-28, 72, 83
See also:
Baker Anomaloscope
Bausch & Lomb Anomaloscope
Crawford Anomaloscope
Dimmick Anomaloscope
Double Dichroic Polaroid Anomaloscope
Double Wedge Anomaloscope
Hecht-Shlaer Anomaloscope
Hioki Anomaloscope
Nagel Anomaloscope
Pickford Anomaloscope
Pickford-Nicolson Anomaloscope
Rautian Anomaloscope
AOC Plates—6, 8, 9, 21, 22, 34, 35, 36, 87, 48, 54, 55, 65,
67, 68, 71, 77, 80
AO H-R-R Plates (includes Prototype H-R-R)—4, 11, 16,
18, 21, 25, 26, 28, 29, 31, 32, 33, 35, 36, 37, 40, 47, 48,
50, 60, 64, 70, 71, 76, 77, 78, 81
B-20 Test
See: Farnsworth Dichotomous Tests
Baker Anomaloscope—2
Bausch & Lomb Anomaloscope—80
Beyne’s Chromoptometric Lantern—51, 62
Bostrém Plates (various editions)—4, 8, 9, 25, 29, 42, 43,
81
Bostrém-Kugelberg Plates—4, 7, 8, 9, 25, 26, 29, 35, 36,
87, 70, 71, 81
Chromatoscope—49, 62
Cibis Test (1 & 2)—65
Color Aptitude Test
See: Inter Society Color Council Color Aptitude Test
Color Memory Test—6
Color Rator—44

Color Temperature Meter Anomaloscopes
See: Dimmick Anomaloscope
Double Wedge Anomaloscope
Color Threshold Tester
See: SAM—CTT
Crawford Anomaloscope—13, 14
D-15 ‘Test
See: Farnsworth Dichotomous Tests
Dimmick Anomaloscope (Single Wedge)—17, 22, 80
Double Dichroi¢ Polaroid Anomaloseope—80
Double Wedge Anomaloscope—80
Dvorine Pseudoisochromatic Plates (two editions)—4, 5,
14, 18, 26, 27, 28, 29, 33, 45, D4, 55, 56, 68, 70, 71, 76,
77, 81

Eastman Color Temperature Meter Anomaloscope
See: Dimmick Anomaloscope
Double Wedge Anomaloscope
Edridge-Green Lantern—73
Farnsworth Dichotomous Tests (B-20, D-15, F-20)—
16, 20, 21, 22, 33, 34, 35, 36, 87, 46, 60, 68, 69, 70, 71,
80, 81
Farnsworth Lantern (New London Navy Lantern)—
19, 21, 22, 83, 35, 36, 37, 60, 65, 80
Farnsworth-Munsell 100 Hue Test—3, 5, 6, 20, 84, 45, 58,
68, 69, TL, 81
Farnsworth Tritan Plate—26
Florcontrast—72
Hecht-Schlaer Anomaloscope—80
Hioki Anomaloscope—38, 50
Holmgren Wool Test—19
100 Hue Test
See: Farnsworth-Munsell 100 Hue Test
Inter Society Color Council Color Aptitude Test (ISCC
CAT)—11, 79
International 16 Plate Selection (Sloan Selection)—70
Ishihara Plates (various editions)—4, 7, 8, 9, 10, 12, 13,
14, 16, 18, 21, 25, 26, 28, 33, 34, 35, 36, 37, 41, 42, 43,
45, 47, 50, 51, 57, 60, 62, 64, 65, 70, 71, 73, 76, 77, 80,
81, 83
Lantern Tests
See: Beyne’s Chromoptometric Lantern
Chromatoscope
Edridge-Green Lantern
Farnsworth Lantern
Martin Lantern
RCAF Lantern
RON Lantern
SAM-CTT
Martin Lantern—7
Maxwell’s Spot—st
Meyrowitz Plates—8, 9
Nagel Anomaloscope (Schmidt-Haensch)—1, 5, 7, 15, 16,
33, 34, 35, 36, 37, 38, 50, 60, 65, 66, 67, 68, 70, 71, 77,
80, 81
New London Navy Lantern
See: Farnsworth Lantern

Nystagmus—83
Okayasu Tritan Plate—50
100 Hue Test

See: Farnsworth-Munsell 100 Hue Test
Optokinetie Nystagmus

See: Nystagmus



The same durations were used for the vertical
canals. Stimuli were 4°/sec? accelerations and
decelerations separated by 54 sec of constant
velocity for cats and by 120 sec of constant ve-
locity for humans. In cats, vertical canal stimu-
lation was accomplished by placing each animal
on its right side to locate its sagittal plane at
the center and in the plane of rotation; human
subjects leaned forward with the head turned to
place the sagittal plane of the skull in the plane
(and at the center) of rotation. A  biteboard

and head rest assisted in this positioning. Stim-
uli were presented in a counter-balanced order
as indicated in Table 1.

Neither the cats nor the human subjects had
been used in previous vestibular experiments.
For the humans, this necessitated instruction re-
garding the signalling of subjective events with-
out actual practice in making such judgments;
they reported onset and cessation of apparent
rotation by means of a signal key.

Taste 1, Order of stimulus presentation. All trials comprised stimuli of 4°/sec*, Duration

of the stimulus was either 8.4 or 36 setonds.
vertical canal stimulation.

L and V refer, respectively, to lateral and

Trials
Human Rotation
Subjects Cats Direction 1 a 3 4
Or & Wa 100 & 101 cw 8.4L 36.0 L 8.4V 36.0 V
Nu & Jo 102 & 103 CCW 36.0 L 8.4L 36.0 V 8.4V
Pe & Me 104 & 105 cw 8.4V 36.0 V 8.4L 36,0 L
Fr & Ma 106 & 107 cow 36.0 V 8.4V 36.0 L 8.4L

IV. Results and Discussion.

The 8 animals received only 4 trials (2 lateral
and 2 vertical canal stimulations) on the first
day. Some examples of recorded nystagmus
appear in Figure 1. The critical portion of the
response for several purposes of this study began
at the end of each stimulus. Thus, time measure-
ments were made from the end of each stimulus

(a) to the end of the primary response and (b)
to the start of the secondary nystagmus. The
number of beats of primary nystagmus which
followed stimulus termination was also tabulated.
These data appear in Table 2. In 47 of the 48
comparisons, the primary post-stimulus responses
to the 8.4 sec stimulus exceeded those of the 36
sec stimulus.

‘Tanre 2. Measures of primary nystagmus following the termination of each rotatory stimulus for eats. Each response
value is a mean of responses to an acceleration and a decleration stimulus. Stimuli were 4°/sec* for either 8.4 or 36

seconds.

Time From End of Stimulus to
End of Primary Nystagmus (Sec)

Time From End of Stimulus to
Start of Secondary Nystagmus (Sec)

Beats of Primary Nystagmus
After End of Stimulus

Lateral Vertical Lateral Vertical Lateral Vertical

Cat 8.4 36 84 36 8.4 36 8.4 86 8.4 36 8.4 36
100 9.2 2.5 6.5 0.5 12.9 5.7 11.1 3.4 8.8 2.8 9.0 1.0
101 1.4 7.0 7.9 7.0 14.4 8.7 9.1 9.4 14.8 10.0 11.5 7.8
102 3.2 0.5 25.7 5.7 6.0 0.9 28.3 9.1 3.3 0.5 18.5 4.0
103 4.9 4.4 8.8 4.2 8.1 6.3 18.1 6.2 3.5 1.5 7.5 3.5
104 10.7 54 8.2 3.1 12.0 6.6 10.9 3.9 8.8 2.0 7.0 2.5
105 13.8 6.9 13.6 3.0 15.8 10.4 14.6 4.3 14.5 8.0 10.0 2.8
106 1.5 5.7 6.0 4.8 14.7 7.0 U7 7.2 10.0 4.5 5.5 4.5
107 10.9 8.2 6.0 —1.5* 14.6 11.0 17.5 3.7 75 6.0 6.5 1.0

M= 9.5 5.1 10.3 3.4 12,3 71 14.7 5.9 8.9 4.4 9.4 3.4

* Nystagmus ended during stimulus.