Session
4-Hour 8-Hour 10-Hour

2-Hour

APPENDIX E
1-Hour

each session for each subject.

Pre

Subject

Measure

Aprenpix E.—Control group: Nystagmus measures from the angular acceleration based on three 5-sec samples from

1B 19 2 DAA o 09 09

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MMM ADMANOA
ABE SSH GW

MK
MA
SM
PS
RC
BS
JC
RM
AA
TT

Slow Phase
Nystagmus
(deg/sec)

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MK
MA
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TT

Frequency
Nystagmus
(beats/sec)

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12

Mean
sD



=
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Figure 2. View of the visual display from inside the rotator. With room lights turned out, only the instrument
dial and a dim, partial outline of the cabin interior could be seen by the subject.

3



IV. Discussion.

Although alcohol effected an increase in track-
ing errors during static performance tests, the
increase was significantly above pre-drinking
levels only during the 1-hour session. Moreover,
differences between the Alcohol and Control
groups in static tracking error were significant
only during the 4-hour session when the effects of
alcohol were beginning to wane.

However, during vestibular stimulation, the
eye-hand coordination required by the tracking
task showed marked impairment by alcohol for
the 1-, 2-, and 4-hour sessions in comparison. both
with the Alcohol group’s pre-drinking perform-
ance and with the steady improvement demon-
strated by the Control group. The extent of this
impairment appears to be directly correlated with
the increased nystagmic activity to angular ac-
celerations following alcohol ingestion. Thus,
degradation of eye-hand coordination during
stimulation of the semicircular canals appears to
be closely related to the alcohol-induced loss of
the ability to maintain adequate visual fixation
(and visual acuity) on an object and thereby
inhibit nystagmus. A similar degradation of
visual acuity and tracking performance without
alcohol has been reported previously.3* How-
ever, the magnitude of vestibular stimuli for
commensurate losses was necessarily greater in
those studies since, without alcohol, the visual
fixation mechanism suppressing nystagmus was
functioning normally.

These data have several practical implications.
Activities which show little or no impairment in
static situations following alcohol ingestion may
be seriously degraded during motion. Further,
the task required of the subjects here was a rela-
tively simple one, ie, the subject could con-
centrate on the single stimulus display. How-
ever, in many work activities, such as piloting an
aircraft, the attention of the pilot has to shift
from one stimulus “display” to another. It has
been shown that deleterious effects of alcohol on
performance in static situations are greatest when
time-sharing of attention across several tasks is
required? or if the task requires “divided at-
tention.”* The addition of motion to a complex
time-sharing task where performance is already

degraded by alcohol might be especially hazard-
ous.

As a final point, it should be noted that the
average blood-alcohol levels obtained in this
study were considerably below the legal defini-
tions, in most state motor vehicle statutes, of
when an individual is presumed to be under the
influence of intoxicating liquor. (The District
of Columbia and 23 state laws cite a blood
alcohol level of .150% or more as a presumptive
legal index; 21 states use .100%. Utah uses
.080% as presumptive, and several other states
are considering reducing their current levels to
080%. Five states have no defined levels.)?
Only three subjects exceeded .090% during any
of the blood-sampling periods.

Vv. Summary.

Following practice, two groups of 10 subjects
each were given Pre (base-line) tests of tracking
performance in both static (stationary) and
dynamic (whole body angular acceleration) con-
ditions. One group then received orange juice
which contained 2.0 ml of 100-proof vodka per kg
of subject weight; the other group drank orange
juice with a few drops of rum extract added.
All subjects were led to believe that they were
receiving alcohol. Additional tests were con-
ducted 1, 2, 4, 8, and 10 hours after drinking.
All tests were in total darkness with the exception
of the visual display which was illuminated to
recommended levels for cockpit instruments.
Static tracking error declined slightly for the
Control group, but increased over the Pre-
drinking level during the 1-, 2-, and 4-hour tests
for the Alcohol group; only the 1-hour scores
differed significantly from the Pre scores for the
Alcohol group. In comparing the two groups,
static tracking errors for Alcohol subjects were
significantly higher than those of Control sub-
jects only at the 4-hour session when the effects
of alcohol were beginning to wane. However, in
the dynamic tests, Alcohol subjects made signifi-
cantly more tracking errors than Control subjects
during the 1-, 2-, and 4-hour sessions. These
data suggest that hand-eye coordination may
show little or no impairment following alcohol
ingestion in static situations, yet may be seriously
degraded during motion.


+307 STATIC +307 DYNAMIC

2 —* contro.
w oe
By +20b sok ALCOHOL
we
QE +iop aw +10b
“Zz

fo) ° PRE LEVEL

tL

i
T
3
T

DECREASE
IN ERROR (%)
.t
8.8
—T
a
$8
TT

1 2 3 4 5 6 7 86 9 0 1 2 3 4 S$ 6 7 8 9 10

NUMBER OF HOURS AFTER ALCOHOL INGESTION
Figure 8. Changes in tracking error under static (stationary) and dynamic (angular acceleration) conditions.
‘The “0” lines represent the base-levels of tracking error during the Preliminary trials. Tracking error scores
for the five post-drinking sessions were converted to percentages of increase or decrease from the base levels.

Means and standard deviations for the slow 3 where they are presented as percentages of in-
phase and frequency measures of nystagmus and crease or decrease in tracking error based on the
for the tracking error in both static and dynamic pre-drinking level. Representative tracings of
conditions appear in Table 1 (individual scores nystagmus during dynamic tracking are depicted
are in Appendices C through E). Changes in in Figure 4 and plots of the nystagmic measures
performance across sessions are shown in Figure across sessions are in Figure 5.

SUBJECT: DW ALCOHOL GROUP
ALCOHOL

PRE fd
1-HOUR Pr rit
10-HOUR D4—

3-Sec
-—

SUBJECT: MA CONTROL GROUP

BRE

INSTRUMENT DIAL ILLUMINATION LEVEL: 1.0 FOOT LAMBERT

Friourr 4. Tracings of nystagmus during angular accelerations. ‘The eye-movement activity clearly increases fol-
lowing alcohol ingestion.

5



E. Procedure. Prior to being tested, each sub-
ject was given five min of tracking practice with
the cockpit stationary. The experimental se-
quence which followed comprised six testing ses-
sions: a pre-drinking session and five post-drink-
ing sessions at 1, 2, 4, 8, and 10 hours after drink-
ing. All sessions, practice and experimental, were
conducted with the room in total darkness with
the exception of the visual display. Immediately
before each testing session, venous blood samples
of from three to five cc were drawn for analysis
of blood alcohol levels by gas chromatography.
(Tests of positional alcohol nystagmus were also
performed; see Appendix A.)

Each session consisted of a two-min “static”
tracking trial with the cockpit stationary and a
four-min “dynamic” tracking trial with the cock-
pit rotating through five complete cycles (240
sec). The order of these trials was alternated
across subjects and at least a 1-min interval was
allowed between trials. Eye-movement calibra-
tions were obtained prior to each period of
dynamic tracking.

F. Scoring. The tracking errors for one-sec
intervals were summed and an average value was
obtained for each static and dynamic trial.

Measures of nystagmus included the number of
nystagmic beats and the amount of slow phase
eye displacement occurring in three 5-sec inter-
vals during each dynamic tracking trial; one
sampling inteval was 32-37 sec from the start,
one was 131-136 sec from the start, and the other
was 10-15 sec from the end of each trial. The
sampling intervals were chosen to include maxi-
mum nystagmus output in a single direction near
the beginning, middle, and end of each test
period. Mean values in deg/sec or beats/sec were
calculated and used to represent nystagmus
output.

Hil. Results.

The following average values of ethanol were
obtained for the Pre, 1-, 2-, 4-, 8-, and 10-hour
samples, respectively, from the Alcohol group:
0%, 074%, 073%, .047%, .001%, and 0%. Con-
trol group subjects yielded no evidence of ethanol
in their blood samples (see Appendix B).

Tanz 1.—Means and standard deviations by session for tracking error (arbitrary units), slow phase nystagmus (deg/sec)
and, frequency of nystagmus (beats/sec).

Session
Measure Group Condition
Pre \-Hour 2Hour 4Hour 8Hour 10-Hour
Performance:
Control Static Mean 5.43 5.21 4.74 4.51 4.77 73.
sD 1.7L 0.86 0.52 0.59 0.41 0. 53
‘Tracking Error
Control Dynamic Mean 6.73 5.44 5.06 4.88 4.91 4.50
sD 1.86 0.65 0.65 0.52 0.51 0.55
Aleohol Statice © Mean 5.20 92 5.86 5.78 4.74 4.84
sD 1.46 1.15 1.01 1.28 1.74 0.62
‘Tracking Error
Alcohol Dynamie Mean 5.97 7.51 6.85 6.02 4,70 4,89
sD 1.14 0. 82 1,13 0.88 1,32 0. 54
Nystagmus:
Slow Phase Control Dynamic Mean 5.42 3.30 3.29 3.06 2.35 3.10
sD 2.83 2.16 1.81 2,24 1,37 1.54
Frequency Control Dynamic Mean 1.40 1.54 1.57 1.42 1.16 1,24
SD 0.91 1.05 0.86 0.94 0.75 0.73
Slow Phase Alcohol Dynamic Mean 3.85 12,15 9.16 6.01 2.82 2.82
sD 3.10 5.45 4.60 4,54 2.31 3.18
Frequency Alcohol Dynamic Mean 1.53 3.70 3.31 2.51 1,29 1.19
sD 1.10 1.06 1.09 1.16 0.83 0.72



A. Control Group. The Control group evi-
denced only a slight decline in static tracking
error (an expected improvement with practice)
from the Pre through the 10-hour session. None
of the changes was statistically significant (Table
2). However, dynamic tracking error evidenced
a fairly steady decline from the Pre through the
10-hour testing sessions; all 1- to 10-hour error
scores were significantly (p<.05—.01) below the
Pre scores (Table 2). Frequency measures of
nystagmus for Control subjects showed no sig-
nificant change (see Table 2) across the six ses-
sions, nor was there any significant difference in
slow phase ocular velocity across the last five
sessions; however, all but the last session of the
latter were significantly below (p<.05—.01) the
Pre test level of slow phase activity.

B. Alcohol Group. In contrast to Control sub-
jects, both the average static and dynamic track-
ing errors increased for the Alcohol group at the
1-, 2-, and 4-hour testing sessions; however, only
the increase for the 1-hour static session (p<.05)
and for the 1- and 2-hour dynamic sessions
(p<.05—.01), were significantly above the re-
spective Pre values (Table 2). Measures of
nystagmus for Alcohol subjects also presented a
totally different picture from that of the Control
group. Both the deg/sec and the beats/sec meas-
ures increased significantly (p<.05—.001) from
the Pre tests through the 1-, 2-, and 4-hour tests.

At the 8- and 10-hour tests, nystagmus was below
the Pre levels, but not significantly so (see
Table 2).

©. Comparison of the Control and Alcohol
Groups. Tn comparing the two groups, t tests
were conducted on “change” (or difference)
scores, ie. the differences in scores between the
Pre and the 1-hour sessions, the Pre and the
2-hour sessions, ete. (see Table 3).

Static tracking differences between the Control
and Alcohol groups were significant (p<.05)
only for the 4-hour session. However, in the
dynamic condition, differences between the two
groups were significant (p<.01—.001) at the
1-, 2-, and 4-hour sessions; thus, with the addition
of motion, the Alcohol group performed with
significantly more errors than the Control group
during the first four hours following alcohol
ingestion (Table 3).

With respect to nystagmus, the Control group
had significantly less slow phase velocity
(p<.001) and frequency of nystagmus (p<.0l
—,001) than did the Alcohol group for the 1-, 2-,
and 4-hour sessions, and less slow phase nystag-
mus (p<.05) for the 8-hour session. Thus, the
Alcohol subjects were less able than Control
subjects to suppress their eye movements by fixa-
tion on the visual display during angular ac-
celeration.

Tapue 3.—Results of t tests comparing Aleohol subjects with Control subjects on measures of nystagmus and tracking
error. Comparisons were made between difference scores for each session (j.e., the difference in scores of each post-

ingestion session from those of the pre-ingestion session).

Comparisons: Aleohol vs. Control Group

1-Hour 2-Hour 4-Hour 8-Hour 10-Hour
Nystagmus Measure
Slow Phase 8, 24 7, SBF 4, 37 2,20* 1.03
Frequency - 5, 44 er 4, S24 3. 56** 0,00 —0.56
‘Tracking Error
Static. -_----------- 1.70 1.06 2,.13* 0.12 0.38
Dynamic. .---.----- 4,254" 4,14 3.31** 0.74 1.72
*p <.05
ep <.01
*et DD < 001



TECHNICAL REPORT STANDARD TITLE PAGE

1, Report No. 2. Government Accession No. 3. Recipient's Catalog No.
FAA-AM-71-20

4. Title and Subtitle 5, Report Date
ALCOHOL AND DISORTENTATION-RELATED RESPONSES, rr, |_APFil 1971

EFFECTS OF ALCOHOL INGESTION ON TRACKING PERFORMANCE | & Performina Oroonization Code
DURING ANGULAR ACCELERATION

7 author's) William E. Collins, Ph.D., Richard D. &. Performing Organization Report No
Gilson, Ph.D., David J. Schroeder, Ph.D.,
and Frederick E, Guedry, Jr., Ph.D

9, Performing Organization Name and Address 10. Work Unit No.
FAA Civil Aeromedical Institute TT. Contract or Grant No.
P.O. Box 25082
Oklahoma City, Oklahoma 73125 13. Type of Report and Period Covered

12. Sponsoring Agency Name ond Address

Office of Aviation Medicine

Federal Aviation Administration
800 Independence Avenue, S.W. 14. Sponsoring Agency Code
Washington, D. C. 20590

OAM Report

15. Supplementary Notes

This research was conducted under Task No, AM-A-71- PS¥27.

16. Abstract

Most studies of the effects of alcohol on human performance involve static
(absence of motion) situations. However, the addition of motion, involved in such
activities as piloting an aircraft, might well produce impairments not usually
obtained in static situations. The present study examined some of the effects of
alcohol ingestion on visual tracking performance (eye-hand coordination) during
angular acceleration. Following practice and base-line tests of tracking perfor-
mance in both static (stationary) and dynamic (whole body angular acceleration)
conditions, 10 subjects received orange juice which contained 2.0 ml of 100-proof
vodka per kg of subject weight; another 10 drank orange juice with a few drops of
rum extract added. Tests, conducted 1, 2, 4, 8, and 1O hours after drinking, were
in total darkness with the exception of the visual display which was illuminated
to recommended levels for cockpit instruments. Static tracking errors for Alcohol
subjects were significantly higher than those of Control subjects only at the
4-hour session. However, Alcohol subjects made significantly more dynamic tracking
errors than Controls during the l-, 2-, and 4-hour sessions, These data suggest
that eye-hand coordination may show little or no impairment following alcohol
ingestion in static situations, yet may be seriously degraded during motion.

17. Key Words 78. Distribution Statement
Alcohol Availability is unlimited. Document may
Performance be released to the National Technical
Nystagmus Information Service, Springfield, Virginia
Angular Acceleration 22151, for sale to the public.

Vestibular

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22, Price

Unclassified Unclassified 14 $3.00

Form DOT F 1700.7 (8-69)



APPENDIX C

Avpunprx C.—Control group: Tracking error in arbitrary units under static and dynamic conditions.

Session
Condition Subject Pre 1-Hour 2-Hour 4-Hour 8-Hour 10-Hour
MK 2,89 3.79 3.63 3.01 4.09 3.98
MA 5.76 5,20 4,25 4,25 4,59 4.84
SM 4,23 5.50 5.32 5.05 5.36 4.34
PS 4,56 5.12 5.19 5.18 5.41 5.31
Static RC 5.54 5.56 4,90 5.07 4.68 5.93
BS 3.40 4.20 4,80 4.50 4,60 4,20
JC 6.90 6.06 4.67 4,24 4.33 4,80
RM 4.86 5.16 5.16 4.46 4,78 4,56
AA 7.94 6.94 5.21 4,82 5.17 4.77
TT 8.17 4,54 4,27 4,60 4.68 4,54
Mean 5.43 5.21 4,74 4,51 4,77 4.73
8D L711 0. 86 0. 52 0.59 0.41 0.53
MK 5.53 4,64 4,23 3.96 3.94 3.77
MA 6.96 5.68 5.60 4,74 5,46 4.26
SM 5.90 5.35 4,69 5.01 5.07 5.15
PS 5.69 6.23 5.15 5.26 5.50 5.46
Dynamic RC 7.34 6.33 6.45 5.76 5.36 4,94
BS 3.71 4,08 4,06 4,24 4,39 3.84
JC 9.19 5.89 4.95 5,29 4,85 4.62
RM 4,95 5,42 5,13 4.82 4,42 4.39
AA 10. 04 5.56 5.43 5,25 5.35 4.70
TT 8.01 5,21 4,88 4.44 4,72 3. 88
Mean 6.73 5.44 5.06 4,88 4,91 4,50
sD 86 0.65 0.65 0, 52 0.51 0.55

10


APPENDIX A
Positional Alcohol Nystagmus
For possible supplementary information, tests of positional alcohol

nystagmus were performed before each testing session and immediately after
the blood samples were drawn. The subject assumed a supine position and
was instructed to position his head upright, to the left, upright, to the right,
and upright again, while in total darkness with his eyes open. Each position
was held for 45 sec while the subject performed a mental. arithmetic task.
Nystagmic responses were recorded on an Offner type T electroencephalo-

ph and calibration was accomplished prior to each positional series by
instructing the subject to sweep his eyes between special ceiling markers
subtending 20 deg of visual angle.

Ratings of positional nystagmus showed fairly consistent results. PAN I
responses were rated as strong and as about equally vigorous during the
1-hour and 2-hour post-alooho! sessions; a reduction in output of about %
occurred in the 4-hour session. All but one subject showed typical PAN I
responses; the exception (subject BR) gave only weak occasional nystagmus.
PAN II responses were obtained from eight subjects during the 8-hour
session and were rated as being slightly more vigorous than the 4-hour PAN
Tnystagmus. Only five subjects yielded PAN IT responses during the 10-hour
session.

APPENDIX B

Apranv1x B.—Blood alcohol levels in percent determined by gas chromatography for Alcohol and Control subjects.

Control Group Alcohol Group
Session
Subject Pre Subject Pre 1-Hour 2-Hour 4-Hour 8 Hour 10-Hour
MK 0 MB 0 .077 - 063 042 0 0
MA 0 BR 0 057 -070 053 0 0
SM 0 MC 0 040 055 022 002 0
PS 0 DW 0 064 - 066 -050 ) 0
RC 0 BB 0 +103 - 086 054 0 0
BS 0 JH 0 059 087 047 - 006 0
Jc 0 JU 0 +103 075 056 t) 0
RM 0 BO 0 068, 079 2054, 002 0
AA 0 GP 0 063 +067 +034 +003 0
TT 0 DB 0 101 .079 054 0 0
Mean 0 Mean 0 074 .073 047 -001 0
sD 0 sD 0 021 -010 -010 002 0



14
35
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2 3 + conrrot
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5 Z
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3 x
3 a
ir
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Pre | 2 3 4 5 6 7 8 9 10 Pe ot 2 3 4 $8 6 7 86 9 10

NUMBER OF HOURS AFTER ALCOHOL INGESTION
Ficure 5, Output of sampled nystagmus during each test session for the Control and Alcohol subjects.

Tani 2.—Results of t tests between pre-aleohol and each post-alcohol measure of the slow phase displacement and the
frequency of nystagmus resulting from sinusoidal rotations, and of tracking error under static and dynamic conditions.

Nystagmus Comparisons: Pre vs.

Measure Group 1-Hour 2-Hour 4-Hour 8-Hour 10-Hour

Slow Phase Alcohol — 7. 09*** — 6,31 *** —2,44* +1.70 +1.04
Control +3. 674" +2,84* +2. 80* +3, 59** +2.23

Frequency Alcohol — 6, 5RHH* — 6, 384#* —3. 69** +0. 86 +1.33
Control —0.95 —1.02 -0.17 +1.04 +0.91

Tracking Error Comparisons: Pre vs.

Condition Group
1-Hour 2Hour 4-Hour 8-Hour 10-Hour
Static Alcohol —2,96* = 2.23 1.88 +0.89 $1.24
Control +0. 48 +119 +1.69 +115 +1.29
Dynamic Alcohol — 4, 00** —3.12* 0,32 +2, 60* +3.94**
Control +2,38* +3,05* +3. 35** +3, 25%* +3. 64
*p < .05
*p <.01
HD << 001


Fieure 1. The rotation device with the visual display attached.

with the same white paint as the display needles.
This card was placed in the light, just in front
of the display, and measurements were made
with a MacBeth illuminometer from the subject’s
viewing position. The voltage across the bulb
was adjusted until the luminance was 1 ft.L, a
level recommended for aircraft instruments.’

C. Recording. Silver disk electrodes taped to
the outer canthi of the eyes and a reference
electrode on the forehead were used to record eye
movements by the corneoretinal potential method
with a 3-sec preamplification time constant.
Calibration of horizontal eye movements was ac-
complished with two small, alternately-flashing
lights, horizontally separated to subtend a visual

angle of 15 deg. Integrated tracking error, eye
movements, and rotational velocity were simul-
taneously displayed on an Offner type T
electroencephalograph.

D. Alcohol Ingestion. Subjects in the alcohol
group consumed a mixture of 100-proof Smirnoff
vodka and orange juice. The mixture (900 ml)
contained 2.0 ml of vodka per kg of body weight.
Control subjects received only orange juice with
a few drops of rum extract added to alter the
odor and taste of the beverage. (‘They were led
to believe that they were drinking alcohol.) AIL
subjects consumed their drinks within a 30-min
period.


Session
4-Hour 8-Hour 10-Hour

2-Hour

APPENDIX F
1-Hour

session for each subject.

Pre

Subject

Measure

Appenvrx F.—Alcohol group: Nystagmus measures from the angular acceleration based on three 5-sec samples from each

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Nivsddwdcd

antnenonms
Sssedaeb ina
ants =

HID MDOH OD

Slow Phase
Nystagmus

6.01
4,54

9.16

4,60

12.15
5.45

3.85
3.10

Mean
sD

DODMNAMOTHA

AdidtnAdcdsd

ROHBAMAASH
adddtAtAtdcdd

RRR RADA
Soda sadadca

ANnnAHMMtoOoM

canmnnonoone
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adacdadnadcdd

MB
BR
MC
DW
BB
JH
JU
BO
GP
DB

Frequency
of
Nystagmus

1.06
18



ALCOHOL AND DISORIENTATION-RELATED RESPONSES.
Ill EFFECTS OF ALCOHOL INGESTION ON TRACKING PERFORMANCE
DURING ANGULAR ACCELERATION

I. Introduction.

Schroeder’ * has shown that the ingestion of
alcohol depresses both nystagmus and “vertigo”
sensations to rotatory or caloric vestibular stimu-
lation when subjects are in darkness but, in
illumination, similarly provoked nystagmus is
considerably stronger than it is normally. This
poses some obvious questions regarding the ability
of men to perform visual tasks adequately during
vestibular stimulation after drinking alcohol.
Most studies of the effects of alcohol on human
performance involve static situations, ie., situa-
tions in which the men are not subjected to
motion. It is conceivable that the addition of
motion, which is involved in a variety of activi-
ties, such as piloting an aircraft or driving an
automobile, might produce deleterious effects on
performance not usually obtained in static situa-
tions. Therefore, the present study was designed
to examine some of the effects of alcohol inges-
tion on visual tracking performance during
angular accelerations.

II. Method.

A. Subjects. Twenty male college students,
paid volunteers ranging in age from 21 to 30

This study was conducted at the FAA’s Civil Aero-
medical Institute and was co-sponsored by the FAA, the
Army (U.S. Army Medical Research and Development
Command) and the Navy (USN Aerospace Medical
Research Laboratory, Pensacola). Dr. Collins is Chief
of the Psychology Laboratory and Dr. Schroeder is a
Research Psychologist at CAMI; Lt. Gilson is a Re
search Psychologist and Dr. Guedry is Head of the
Psychophysiology Division at USNAMRL. The expert
assistance of Carl Moore in obtaining the blood samples,
and of Elizabeth Gilson, Carlyn Manley, Cynthia Coch-
ran, and Blair Fennell in the collection and scoring of
data are gratefully acknowledged. Gas chromatographic
analyses of the blood samples were performed under
contract by Dr. Kurt Dubowski, University of Oklahoma
Medical Center.

years, served as subjects. None had previous
laboratory experience involving vestibular stimu-
lation. Each subject was assigned at random to
one of two equal groups: a Control and an
Alcohol group.

B. Apparatus. Angular acceleration was sup-
plied by a Stille-Werner RS-3 rotator fitted with
a small cockpit (see Figure 1) in which the sub-
ject was enclosed and seated upright with his
horizontal semicircular canals approximately in
the plane of rotation. A fitted headrest helped
to maintain the desired position. A triangular
waveform input from a Wavetek model 155 wave-
form generator was used as a command signal for
the rotator. The velocity of the latter was pro-
portional to the input voltage and a peak angular
velocity of 120°/sec was attained in both the
clockwise and counterclockwise directions. The
waveform period was 48 sec.

A compensatory visual tracking task provided
both a direct practical measure of performance
and an indirect measure of acuity. The track-
ing apparatus has-been described jn detail else-
where Briefly, a 14-sec sinusoidal “forcing
function” input deflected the vertical needle of an
aircraft localizer/glide-slope indicator while the
subject attempted to maintain the needle in the
null position by manipulation of a control stick.
Deviations of the needle from this position were
considered errors, and a voltage proportional to
these deviations was electronically integrated.
over consecutive 1-sec intervals throughout a
trial.

The display was illuminated by a 8vDC bulb
mounted in a tube in front of the subject, but
below his line of sight (see Figure 2). Light
was projected through the tube to localize on the
display and to minimize reflection in the other-
wise darkened room. The luminance of the dis-
play was measured with the aid ofa card sprayed





APPENDIX D

Appenvix D.—Alcohol group: Tracking error in arbitrary units under static and dynamic conditions.

Session

Pre 1-Hour 2-Hour 4-Hour 8-Hour 10-Hour

Subject.

Condition

4.96
4,95
3.99
5,26
5,57
5,27
791
8.02
6.86
5.01

4,98
5.31
4.36
5.73
5.81
5.38
7.04
7.78
6.94
5.30

4,90
5,21
4,98
5.88

4.79
5.36
4.13
4,25
4.54
4.42
6.32
8.03
7.60
3.45

MB
BR
MC
DW
BB
JH
JU
BO

5.59
4,98
6.69

Static

4,81
4.79
4.08
4.66
4.36
4,34
5,66.
5.68
5.54
5.01

3.79
2,48
3.00
5,42
4.99
4,02
7.16
5.68
4.90
5.55

5.41
5.58
4.75
5.85
5.57
5.99
6.63
7.86
7.13
5.45

6.40
5.99
5.39
5.79
7.78
7.15
8.19
8.49
7.87
5.42

5
1

8.47
7.36
5.12
5.92
4.15
7.03
6.79
6.80
6.77
8.79
8.65
7.86
8.42
7,42
6,53

5.29
1,46
5.06
6.00
4,93
5.65
5.18
5.79
6.41
7.95
8.10
4.65

GP
DB
Mean
sD
MB
BR
MC
DW
BB

Dynamic

4.89
0. 54

6.02
0.88

JU
BO
GP
DB

i



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