AM 67-12 

ADAPTATION TO VESTIBULAR DISORIENTATION. 

VII. SPECIAL EFFECTS OF BRIEF PERIODS OF VISUAL FIXATION 

ON NYSTAGMUS AND SENSATIONS OF TURNING 

Approved by 

J. RoBERT DILLE, M.D. 

CHIEF' CIVIL AEROMEDICAL 

INSTITUTE 

William. E. Collins, Ph.D. 

May 1967 

Relea~ed by 

P. v. S!EGEL, M.D. 

FEDERAL Am SURGEON 

FEDERAL AVIATION ADMINISTRATION 

Office of Aviation Medicine 
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 
ADAPTATION TO VESTIBULAR DISORIENTATION 

VII. Special Effects of Brief Periods of Visual Fixation 

on Nystagmus and Sensations of Turning 1 

1. The Problem. 

In spite of daily exposure to strong angular 

accelerations, figure skaters show brisk vestibular 

nystagmus, experience motion, and can become 

disoriented when vestibular testing is conducted 

in the absence of visual information.4 Even when 

ocular fixation on external objects is permitted, 

extremely brief periods of vertigo and blurred 

vision occur immediately following the skaters' 

high-velocity (up to 300 rpm) on-ice spins. The 

present study was undertaken to elucidate some 

of the mechanisms by which control of vestibular 

function is achieved through vision and to evaluate the effects of the skaters' experiences on their 

vestibular responses. 

II. Method. 

Subjects. Four male and four female skaters 

and four male and four female non -skaters were 

tested in the Stille-Werner RS-3 Rotation Device 

under identical conditions. Two practice trials 

were· given in total darkness to familiarize the 

subjects with the test situation and to provide 

them with some practice in making subjective 

estimations of their acceleratory experiences. 

Recording. Surface electrodes were taped by 

the outer canthi of the subject's eyes to record 

horizontal components of eye movements. A 

ground electrode was clipped to the ear lobe. 

Recording was accomplished by means of an 

Offner Type T polygraph. RC time constants of 

3-sec were used in amplification. Subjects were 

provided with a microswitch, connected to the 

recorder, by means of which signals indicating 

the subjective onset and termination of motion 

could be made. 

Procedure. Subjects were seated in the rotation device with their heads upright but anteverted so that the lateral semicircular canals were 

'Assistance rendered by Ruth Ann Mertens, Billy P. Updegraff, 

and David Schroeder is gratefully acknowledged. 

1 

approximately in the plane of rotation. ~hey 

were instructed regarding the sequence of stimulus events and were given two familiarization 

trials. 

Experimental trials comprised the following 

sequence: 

1 & 2) "Dark" Trials: Acceleration 5° jsec2 

for 18 sec, 2 min constant velocity, deceleration 

5° jsec2 for 18 sec. 

3 & 4) "Light" Trials: Acceleration 5° jsec2 

for 18 sec, 2 min constant velocity, deceleration 

5° jsec2 for 18 sec. 

5 & 6) "Dark" Trials: Acceleration 15° jsec2 

for 6 sec, 2 min constant velocity, deceleration 

15° jsec2 for 6 sec. 

7 & 8) "Light" Trials: Acceleration 15° jsec2 

for 6 sec, 2 min constant velocity, deceleration 

15° jsec2 for 6 sec. 

9 & 10) "Dark" Trials: Acceleration 15° jsec2 

for 6 sec, 2 min constant velocity, deceleration 

90° jsec2 for 1 sec. 

11 & 12) "Light" Trials: Acceleration 15° jsec2 

for 6 sec, 2 min constant velocity, deceleration 

90° jsec2 for 1 sec. 

Half of the subjects in each group were given 

CW accelerations on odd-numbered trials and 

CCW accelerations on even-numbered trials; directions were reversed for the remaining subjects. "Dark" trials were conducted in total 

darkness. "Light" trials were also in total darkness with the exception of a 3-sec period (which 

began one sec after the termination of deceleration) when the room lights were turned on. During this period of illumination, subjects were 

instructed actively to fixate on the nearest to 

straight-ahead vision of a series of eye-level 

markers attached to the walls of the room. At 

the end of the 3-sec period, room lights were 

again turned off. 

Scoring. Only deceleration responses were 

scored. Three measures were obtained for pri831 
mary nystagmus: duration, frequency, and slowphase displacement. Duration was measured 

from the point at which the deceleration began 

to the last beat of the primary response. Frequency measures were obtain simply by counting 

the number of eye movements per 3-sec interval. 

Slow-phase displacement was calculated by measuring the vertical distance from the peak to the 

baseline of each nystagmic eye movement; these 

values were summed for 3-sec intervals and converted to degrees by means of calibration procedures employed prior to each trial. Measurement of secondary nystagmus was limited to the 

first 30 sec of response; thus, only slow-phase 

and frequency data were tabulated. Subjective 

reactions were examined from two points of view : 

latency (time from stimulus onset to first signal 

of experienced motion) and duration (time from 

stimulus onset to signal indicating end of experienced motion). 

III. Results and Discussion. 

Comparisons of Nystagmic Output. Mean 

slow-phase eye displacement, frequency of eye 

movements, and duration of primary nystagmus 

were tabulated independently for "dark" and 

"light" trials for skaters and non-skaters. These 

values appear in Table 1. For slow-phase and frequency measures, there is little difference between 

directions for skaters. For non-skaters, OW deceleration produced consistently more output than 

COW stimulation, but this is entirely attributable 

to a single female subject who showed a marked 

directional preponderance of nystagmus. Duration data show no clear patterns of directional 

differences for either group of subjects. 

The data for the two directions were combined 

and analyses of variance were performed. The 

analyses indicated that for primary nystagmus, 

the duration, the number of eye movements, and 

the total slow-phase displacement of the eyes 

were significantly greater (p> .001) for "dark" 

trials as compared with "light" trials for both 

skaters and non-skaters, Similarly, both groups 

of subjects showed significant differences in output (p> .001) for all three measures as a function of stimulus rate (although all three stimulus 

rates brought the subjects to a complete stop from 

15 rpm, the 18 sec stimulus resulted in the greatest output of nystagmus). 

In comparing skaters with non-skaters, the 

duration and frequency measures yielded no statistically reliable differences. However, nonskaters showed significantly greater (p > .05) 

slow-phase output compared with skaters for 

the three rates of stimulation. 

The average nystagmic responses for each of 

the two groups of subjects were plotted in 3-sec 

intervals for the three stimulus rates. These 

plots of slow-phase displacement and frequency 

appear in Figures 1, 2, and 3. The greater slowphase output for the non-skater group is evident 

TABLE 1. Mean slow-phase eye displacement, number of eye movements, and duration 

of primary nystagmus for OW and COW deceleratory stimuli for each trial and 

stimulus rate. The consistently greater output (slow-phase displacement and number 

of beats) to OW stimulation for non-skaters is attributable to a single subject with 

a marked directional preponderence. 

Slow-phase Number of Duration 

(Degrees) Beats (Seconds) 

Stimulus Subjects Trial ow caw ow cow ow cow 

5° /sec• Skaters Dark 744 841 84 93 50 56 

Light 482 493 63 67 42 39 

Non-Skaters Dark 1099 1053 91 95 60 63 

Light 675 602 72 66 45 44 

15° /sec• Skaters Dark 619 624 75 77 44 46 

Light 319 347 50 55 32 40 

Non-Skaters Dark 948 871 82 76 49 47 

Light 545 516 65 60 32 33 

90° ;sec• Skaters Dark 625 624 71 74 42 42 

Light 262 258 40 41 25 29 

Non-Skaters Dark 899 771 78 68 46 40 

Light 394 364 65 48 28 29 

2 
throughout the course of the response in each 

case. For frequency data, the skaters tend to 

have a number of eye movements equal to or 

greater than that of the non-skaters during the 

stimulus and for a few seconds thereafter on 

"dark" trials. A similar trend is evident during 

the stimulus of "light" trials but, as soon as the 

period of visual fixation is introduced, the skaters' average eye-movement frequency drops off a 

little more rapidly. The skaters may thus be 

demonstrating a somewhat greater ability than 

the non-skaters to influence vestibular nystagmus 

as a result of even so brief a period of visual 

fixation. 

Secondary nystagmus was also plotted in Figures 1-3. Analyses of variance of total slowphase displacement and total number of eye 

movements for the 30-sec period of scored activity yielded no statistically reliable difference between. skaters and non-skaters, nor was the output of secondary nystagmus for this period of 

time related to the rate of the angular deceleration (and thus not to the amount of primary 

nystagmus). Relationships between primary and 

secondary nystagmus and between stimulus duration and magnitude of the secondary response 

have been demonstrated in other studies,5•

8 but 

for a different range of stimulus values. 

Infouence of Visual Fiwation. As noted above, 

the introduction of the light and the opportunity 

for active visual fixation resulted in a significant 

shortening of the primary nystagmic response 

and a significant reduction in the primary slowphase and frequency measures for both groups of 

subjects (see Figures 4, 5, and 6). The skaters 

appeared to demonstrate more rapid response decline during the period of darkness following 

visual fixation than did non-skaters. Coupled 

with these reductions was a significant increase 

(p> .01 for slow-phase; p> .001 for frequency) 

in the output of secondary nystagmus during 

"light" trials. In addition to being more pronounced, the secondary reaction appeared much 

earlier following the "light" period than it did 

during "dark" trials. Some striking examples of 

these effects are evident in the tracings presented 

in Figures 7, 8, and 9. The opportunity to see 

stationary visual objects also shortened the subjective after-sensation. 

Secondary Nystagmus. A number of authors 

have expressed the view that secondary nystag3 

nms is due to central rather than peripheral 

events.1 •

14 In addition, Guedry, Cramer, and 

Koella10 ascribed secondary subjective reactions 

to processes which developed to counteract primary subjective reactions. It is felt that _the 

marked secondary responses obtained in this 

study following a brief period of active visual 

fixation may lend support to both of these views. 

The present data are interpreted as indications that secondary nystagmus is of central origin, that the secondary reaction is a process which 

opposes the primary (whether it is initiated to 

do so, or occurs as a consequence of some central 

imbalance produced by "prolonged" activity in 

one direction) , and that visual information signalled during a period of active ocular fixation 

is centrally integrated and enhances this already 

on-going opposed process (under some conditions) , thereby attenuating the primary response. 

Subjective Responses. Latency and duration 

of subjective turning reactions were calculated in 

seconds for both acceleration and deceleration 

stimuli for the two directions of rotation. Data 

were combined for those stimuli which produced 

sensations in the same direction (e.g., CW acceleration and CCW deceleration for right-turning sensations). All latency scores (Table 2} 

were subjected to analysis of variance and yielded 

only one main effect: the higher stimulus rates 

produced shorter subjective latencies (p> .01}. 

Duration data (Table 2) also yielded a significant effect for stimulus rate (p> .01) with the 

higher rates of angular acceleration producing 

shorter durations of turning sensations. In addition, skaters had significantly shorter durations 

of the subjective response (p> .01) than did nonskaters. For duration analyses, no test was made 

of dark deceleration scores versus those obtained 

when the light was introduced. This was due to 

the fact that on only one occasion (for a total 

of 6 sec) did any skater experience motion after 

the introduction of the light, whereas in 17 of 

the 48 cases, non-skaters experienced some further (although markedly reduced) sensation of 

motion after the light was turned off. · Thus a 

clear difference in duration of sensation between 

skaters and non-skaters was evident even after 

introduction of the brief period of visual information. 
TABLE 2. Mean latency (from stimulus onset to subject's first signal) and duration (from stimulus 

onset to subject's final signal) in seconds for subjective reactions to three rates of angular stimulation. Unless otherwise indicated, scores are means 

for appropriately combined acceleration and deceleration stimuli. R- and L- turns indicate the duration of the subject's turning sensation. D and L 

refer to "dark" and "light" trials, respectively. 

Latency scores were rounded to the nearest tenth 

of a second ; duration scores to the nearest second. 

Skaters Non-Skaters 

R-turn L-turn R-turn L-turn 

Rate Trial Latency 

5° ;sec• D 2.4 2.4 2.8 2.3 

L 2.8 2.8 2.6 2.4 

15° /sec' D 1.1 1.1 1.2 1.2 

L 1.1 1.2 1.1 1.2 

90° ;sec' *D 0.6 0.7 0.5 0.6 

*L 0.6 0.7 0.5 0.6 

Duration 

5° ;sec' D 30 30 36 36 

**L 30 28 33 34 

15° /sec• D 19 15 22 22 

**L 20 17 23 24 

90° /Sec" *D 13 11 18 17 

*L Insufficient Insufficient 

Data Data 

*Means based on deceleration data only (acceleration rate 

was Hi 0 ;sec•) . 

**Means based on acceleration data only (see text). 

Visual-Vestibular I nteraotion. The present 

data indicate that visual stimuli can exert a 

strong influence on the vestibular reactions of 

human subjects. Not only are primary nystagmic 

reactions markedly affected by even a brief opportunity to see stationary visual surroundings, 

but the intensity of the subjective reaction is 

either sharply reduced or the vestibular sensations are abruptly terminated. Further evidence 

for visual-vestibular e:tfects has been presented 

in an earlier study of figure skaters4 where it 

was noted that weak nystagmic responses were 

obtained when skaters were given opportunities 

to fixate visually during laboratory caloric stimulation, whereas eye closure or tests in total darkness. resulted in vigorous responses. Similarly, 

the skaters demonstrated the learned ability to 

bring under rapid visual control, by fixating immediately on some object at the conclusion of a 

spin, the turning sensations and nystagmus which 

would have resulted from their abrupt on-ice decelerations.4 When this practiced opportunity 

to use visual information to suppress actively 

the vestibular consequences of their quick stops 

4 

from high-velocity spins was prevented by eye 

closure, brisk nystagmus, disorientation, staggering, loss of balance, and falling occurred. These 

findings appear to substantiate the view propounded by Wendt11 who indicated that, " ... visual stimuli tend to inhibit the vestibular nystagmus, and with repetition these stimuli become 

increasingly dominant. Such habituation is 

probably not preventable." However, based upon 

data obtained from the skaters, this learned control of vestibular responses appears to transfer 

only incompletely (e.g., reduced slow-phase eye 

excursion and shorter subjective reactions) to 

situations in which vision is not permitted. 

W endt14 also made note that strong nystagmus 

is obtained from human subjects in the absence 

of visual stimuli regardless of practice if subjects are kept alert. 2 

A Modified View of Habituation. Introduced 

by Abels in 1906, the term "habituation," signifying a response reduction, has been employed 

to describe the effects of repeated elicitation of 

vestibular nystagmus. The process has been defined as "a tendency merely to drop out responses.m2 However, it is felt that the term 

"habituation," with its implications of an overall 

depression of responses has limited applicability 

and does not convey adequately some of the processes which may be activated by repeated vestibular (and perhaps other) stimulation. 

The results of this study appear to support 

findings obtained in an earlier investigation2 and 

suggest that a somewhat different view be taken 

of vestibular "habituation" phenomena in humans. In the earlier study, ten subjects were 

each given a series of 200 angular accelerations 

in which only one direction of nystagmus was 

elicited (decelerations were sub-threshold). 

These trials were spaced evenly over a 10-day 

period and, on the days immediately preceding 

and immediately following this 10-day period of 

repeated practice, sets of pre- and post-tests were 

administered in which nystagmus was elicited in 

both directions. A comparison of the pre-· and 

post-test nystagmic responses showed that, for 

both directions of nystagmus, the amount of 

slow-phase displacement of the eyes declined 

throughout the course of the post-test response. 

The number of eye movements, however, showed 

a striking increase during periods of stimulation 

( 4.15° jsec2 for 13 sec) and for a few seconds 

thereafter (although total frequency showed a 
slight decline). This increased activity was 

somewhat greater for the "practiced" direction 

of nystagmus, but was clearly evident for both 

directions. Moreover, the alterations in the nystagmic response pattern were still present one 

month later, with no intervening trials. It 

should be noted that all of the tests were conducted in total darkness. 

Similar findings may be adduced from the 

present study. For all three stimuli (in "dark" 

and "light" trials), the skaters ("practiced" 

subjects) showed less slow-phase displacement 

throughout the course of the responses than did 

the non-skaters ("unpracticed" subjects). However, for the "dark" trials the skaters showed a 

greater frequency of nystagmus during the stimulus period and usually for a few seconds thereafter. This combination of lower-amplitude, 

higher-frequency nystagmus during stimulation 

and immediately following it, seems to be a 

characteristic of the vestibular response pattern 

of alert human subjects after exposure to repeated simple angular stimulation. Similar results have been presented by WendV3 in depicting 

responses to repeated oscillatory motion and to 

repeated single turns of short arc. 

"Habituation," then, when used to signify a 

simple dropping-out of responses, appears not 

to describe adequately the vestibular processes 

which appear as a result of repeated elicitation 

of nystagmus in alert humans (although response declines and overall response depression 

may be characteristics of repeated vestibular 

stimulation of at least some animals6 ). Rather, 

what occurs is a change in the form of the response. Thus, in studies which maintained subjects in states of alertness, a simple "dropping 

out of responses" did not occur even after many 

stimulations, whether rotatory or caloric. 2

•

3 The 

response, however, appeared to be modified and 

perhaps this neutral term "modification" most 

appropriately describes the result of repeated 

simple vestibular stimulation. The modification 

appears to consist of greater fast-phase activity 

during angular stimulation with a concomitant 

reduction in the slow-phase excursion of the eyes. 

The nystagmus also appears to be more regular 

and the response may be thus somewhat better 

5 

"tuned" to the stimulus. The process, then, is 

not a simple reduction but a dynamic change. 

It is suggested that one of the mechanisms basic 

to this change may be the opposed central process evidenced by secondary nystagmus. 

With more complex ("Coriolis") stimulation, 

a marked reduction of nystagmus has been reported as a result of repeated experience.7•

9 •11 

That this apparent "habituation" may also be 

considered a dynamic process, and of the same 

nature as that described above, is suggested by 

the fact that, for a period of time following the 

response modification occasioned by repeated 

head tilts during rotation, head tilts made in a 

static condition (absence of rotation) have resulted in a nystagmic response opposed in direction to that which would have occurred had that 

same head tilt been made while the subject was 

still rotating.8 •

11 

IV. Summary. 

Groups of professional figure skaters and nonskaters were given a series of CW and CCW 

laboratory angular accelerations. Subjects were 

stimulated (a) in total darkness, and (b) in total 

darkness with the exception of a 3-sec period of 

room illumination which commenced one sec after 

a complete stop had been reached. Deceleration 

rates of 5° jsec2 , 15° jsec2 , and 90° jsec2 were applied from turning velocities of 15 rpm. Skaters 

produced significantly less primary slow-phase 

eye displacement than did non-skaters, but the 

groups did not differ in number of eye movements nor in duration of nystagmus. Introduction of the visual still-fixation period significantly shortened primary nystagmus and produced an accentuated secondary nystagmus for 

both groups. The term "habituation" (a "dropping out" of responses), used to define the effects 

of repeated vestibular stimulation, does not appear to describe completely the active process of 

change evidenced in the nystagmic tracings presented in this and other studies. Durations of 

turning sensations were shorter for skaters than 

for non-skaters. For both groups the period of 

room illumination, allowing subjects actively to 

fixate on stationary visual objects, significantly 

shortened or abruptly terminated the subjective 

reaction. 
REFERENCES 

1. AscHAN, G. and BERGSTEDT, M.: The Genesis of 

Secondary Nystagmus Induced by Vestibular Stimuli. 

Acta Soc. Med. Upsal., 60:113, 1955. 

2. CoLLINs, W. E. : Task-Control of Arousal and the 

Effects of Repeated Unidirectional Angular Acceleration on Human Vestibular Responses. Acta Otolaryng., Suppl. 190, 1964. 

3. CoLLINs, W. E. : Subjective Responses and Nystagmus Following Repeated Unilateral Caloric Stimulation. Ann. Oto-Rhino-Lar1fng., 74 :1034, 1965. 

4. COLLINS, W. E.: Vestibular Responses from Figure 

Skaters. Aerospace Med., 37:1098, 1966. 

5. CoLLINS, w. E. and GuEDRY, F. E. : Adaptation to 

Vestibular Disorientation: V. Eye-Movement and 

Subjective Turning Responses to Two Durations of 

Angular Acceleration. OAM Report No. 67-6, 1967, 

Oklahoma City, Oklahoma .. 

6. CoLLINS, W. E. and UPDEGRAFF, B. P. : A Comparison 

of Nystagmus Habituation in the Cat and the Dog. 

Acta Otolaryng., 62 :19, 1965. 

7. GuEDRY, F. E.: Habituation to Complex Vestibular 

Stimulation in Man: Transfer and Retention of Effects from Twelve Days of Rotation at 10 RPM. 

Percept. Mot. Skills (Monog. Suppl. 1-V21), 21:459, 

1965. 

8. GuEDRY, F. E. and CoLLINs, W. E. : Adaptation to 

Vestibular Disorientation: VI. Eye-Movement and 

6 

Subjective Turning Responses to Varied Durations 

of Angular Acceleration. OAM Report No. 67-7, 

1967, Oklahoma City, Oklahoma. 

9. GUEDRY, F. E., CoLLINs, W. E., and GRAYBIEL, A.: 

Vestibular Habituation During Repetitive Complex 

Stimulation : A Study of Transfer Effects. J. Appl. 

Physiol., 19 :1005, 1964. 

10. GUEDRY, F. E., CRAMER, R. L., and KoELLA, W. P .. : 

Experiments on the Rate of Development and Rate 

of Recovery of Apparent Adaptation Effects in the 

Vestibular System. USAMRL Report No. 338, Fort 

Knox, Kentucky, 1958. 

11. GUEDRY, F. E. and GRAYBIEL, A.: Compensatory 

Nystagmus Conditioned During Adaptation to Living 

in a Rotating Room. J. Appl. Physiol., 17 :398, 1962. 

12. THORPE, W. H.: The Concepts of Learning and 

Their Relation to Those of Instinct. In Symposium 

of the Society of Experimental Biology, Physiological Mechanisms in Animal Behavior, Cambridge 

Univ. Press, 4 :387, 1950. 

13. WENDT, G. R. : The Nature of Adaptation to Oscillatory Rotation. In Symposium on the Role of the 

Vestibuiar Organs in the Exploration of Space, 

NASA Report SP-77, 1965. 

14. WENDT, G. R.: Vestibular Function. Stevens, S. S. 

(Ed.), Hand book ot Emperimental Psychology. 

Wiley & Sons, Inc., New York, 1951. 
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FIGuRE 1. A comparison of the primary and secondary nystagmic output of figure skaters and non-skaters to "dark" 

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10 ON 

lt, I I 

9 

8 

7 \ 

\ 

'\ 

I I I I I I I I I I I I I I I I I I I I I I 

18 27 36 45 54 63 72 81 

Non-Skaters 6 

'" \ 

5 \ 

" \ 

4 \ 

" \ 

3 ' "-" \ 2 \ 

" I 

\ 

I 0 

LIGHT h 

ON I 

I 

I 

2 " ':t. .... t. 

"""' / 3 ""'-" 

lt. I I I I I I I I I I I I I I I I I I I I I I I I I 

9 18 27 36 45 54 63 72 81 

Time in Seconds 

140 

130 

120 

110 

100 

90 

80 

70 

60 

50 

40 

0 

I 

I 

I i 

I II 

1 I \ 

II \ 

I I I 

0 

\ 

Skaters 

...,_____ "DARK" TRIALS 

o---o "LIGHT• TRIALS 

\I 30 ~ 0 ' 

20 

10 

0 

LIGHT 

10 ON 

ltc I I I 

9 

8 

7 0 

I 

6 I 

\ 1\ It \ 5 0 '\ 

' ~ 

\ 

~ 

I I I I I I I I I I I I I I I I I I I I I I I 

18 27 36 45 54 63 72 81 

Skaters 

0 

\ 

\ 4 '\ 

\ 

3 \ 

o, 

o, 

2 'o 

\ 

\ 

0 

\ 

\ 

0 

LIGHT I 

ON I 

'\ 

2 

\ 

o..o, 

'o·\ 

3 0 

\ .,.-o-o 

lt. 0" 

I I I I I I I I I I I I I I I I I I I I I I I I I I 

9 18 27 36 45 54 63 72 81 

Time in Seconds 

FrGURE 3. A comparison of the nystagmic output of figure skaters and non-skaters to a 90° ;sec• angular deceleration. Compare with Figures 1 and 2. 

9 
120 

-110 

c 

Stimulus: 5• /sec2 for 18 sec 

~~oo 

i90 .-.-.. SKATERS 

A---6 NON-SKATERS 

~ 80 

.... 70 ! 

= 60 ~ 

~50 0 

Ul 40 :I 

E 30 

~ ~20 

= 10 0 

~o ...... ---------~-=-.a..r----- ~ (i) 10 

g 

... 

~ 

u 

CP 

Ul 

~ 

ll 

8 

7 

6 

5 

I I I It I I I I I I I I I I I I I 

8. 4 '. 

1/) 3 ~'A ~ \ 

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E 2 ~ 

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I I I I I I I I I I 

CP I 

~ 0 ~--------------------~--~~------------ u 

"E~ CJl 

0 

u; 

>. 

z 

0 

... 

~ 

E 

::I 

z 

2 

3 

11 I I I It I 

9 18 

I I I I I I I I I I I It I I I I I 

27 36 45 54 63 72 

Time in Seconds 

I I I I I I I I 

81 90 99 

120 

110 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

10 

8 

7 

6 

4 

3 

2 

2 

3 

o---o SKATERS 

6---6 NON-SKATERS 

1 I I I I It I I I I I I I I I I 

9 18 27 36 45 54 63 72 81 

9 

"LIGHT" TRIAL 

I 

I 

~ 

...... \ 

'-

\ ,. W I 

........ 

18 27 36 45 54 63 72 

Time in Seconds 

81 

FIGURE 4. A comparison of nystagmic output to a 5° /sec' stimulus during "dark" and "light" trials for non-skaters 

and for figure skaters. Scoring and plots are the same as in Figure 1. Note the early onset and greater magnitude of secondary nystagmus during "light" trials. 

10 
150 

140 

1'30 

=120 

§? 

.! 110 c:: 

~100 

en 

• n 

I\ 

I I 

I\ 

I \ 

I I 

I ~ 

. I ' \ I \ I I 

I ~ 

Stimulus: 15 o /sec2 for 6 sec 

~ Skatert 

A---• Non-Sk'Qters 

If) 90 \ 

8. 80 

en 

~ 70 ..... 

01 

~ 60 

..... 

G.> 

0. 

10 

9 

8 

7 

6 

5 

4 

2 

1: It I I 

9 

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I 

~ 

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\ 

"DARK" TRIAL 

'. .... '. '• .... 

I I I I I I I I I I I I I I I I I I I I I I I I I I 

18 27 36 45 54 63 72 81 90 

"DARK" TRIAL 

0~----------------~r.~---------------

2 

3 

t,t, 

9 

\ 

~ . 

v\ \• 'II / \--• 

I I I I I I I I I I I I I I I I I I I I I I I I I I 

18 27 36 45 54 63 72 81 90 

Time in Seconds 

150 

140 

130 

120 

110 

100 

90 

80 

70 

60 

t 

,, 

1\ 

I\ 

I I 

I I 

I I 

I \ 

I I 

I t 

<>----<) Skaters 

6----4 Non-Skaters 

I I ~ I I II 

I I I I 

50 I \I ~ I II I 

"LIGHT" TRIAL 

40 

30 

20 

10 

10 

9 

8 

7 

6 

5 

4 

3 

2 

2 

3 

I X I 

I 

I 

A 

I 

\ 

h 

LIGHT 

ON 

'L·t,, . 9 

LIGHT 

ON 

9 

I I I 

18 

18 

\ \ 

~'A 

I I I I I I 

27 36 45 54 63 72 

"LIGHT" TRIAL 

27 36 45 54 63 72 

Time in Seconds 

FIGURE 5. A comparison of nystagmic output to a 15° ;sec' stimulus during "dark" and "light" trials for non-skaters 

and for figure skaters. Compare with Figure 4. 

11 
140 .. 

A Stimulus: 90°/sec2 for I sec 

130 II 

I I 

I I 

120 I I ________... SKATERS I I .. ' .. •---• NON-SKATERS 

-- 110 I 

0 I 

> I 

~ 100 I 

- I £ .. 90 I u 

CP I en 

!() eo 

.... 8. 70 

en 

~ 60 

01 

CP 50 0 

en 40 ::J 

E 

g 30 

-

en Z' 20 

~ c 

.r; 

Q. 

I 

3: 

0 

iii 

.... 

CP 

Q. 

en 

-

c: 

CP 

E 

~ ::::!!: 

~ w 

10 

0 

10 

e 

7 

6 

5 

4 

3 

2 

il I I I 

9 

.. 

1\ 

I\ 

i • 

\ 

.. 

' ' • I 

\ 

I 

\ 

.. "DARK" TRIAL \ 

\ 

.. 

\ 

\ 

• \ 

'.. 

' ' .. '• \ 

'& '& 

I I I I I I I I I I I I I I I I I I I I I I I 

le 27 36 45 54 63 72 el 

I 

'.. \ 

\ 

\ 

.. \ 

\ 

"DARK" TRIAL 

u 0~----------------t------------­ ·e 

01 

E 

en 

>. 

z 2 

0 

.... 

.8 

E 

::J 

z 

3 

ltl I I I 

9 

I I I I I I I I I I I I I I I I I I 

18 27 36 45 54 63 

Time in Seconds 

I I I I I 

72 81 

140 

130 

120 

110 

100 

90 

eo 

70 

60 

50 

40 

30 

20 

10 

0 

10 

i I I I 

9 

8 

7 f>-t1 

' \ 

6 

' \ " \ 

5 

4 

3 

2 

2 

3 

9 

I 

'• \ 

I 

18 

\ 

• \ 

~SKATERS 

t.---t. NON-SKATERS 

"LIGHT" TRIAL 

I I I I I I I I I I I I I I I 

27 36 45 54 63 

''& "LIGHT" TRIAL 

\ 

\ 

I 

"'& I 

\ 

\ 

18 27 36 45 54 

Time in Seconds 

FIGURE 6. A comparison of nystagmic output to a 90° jsec2 stimulus during "dark" and "light" trials for non-skaters 

and for figure skaters. Compare with Figures 4 and 5. 

12 
!-" 

c.:> 

"DARK" 

SKATER GR 

-t----r---r--...t"'--r-r~.J"""'''""""'·~"""-"N'l\NV'-,r-rJ"''•~~ 

~.r-1'~~~.____,.-.r,....__,.__-

~ I 3()-L 

2HC 

''LIGHT'' ~·,f'~~'~~~...J,....---..r~'\,r·..r-N~-~"' 

,......___,..__,___,...__.---"""'--"'"'--""1,...~--......-! _____ ,__, -UGHT ON 0-""-~ 

~-- 30·L 

2HC 

NON-SKATER HJ 

"DARK" ~~~f'VWW·I\IV~Vl/11Vv~ 

~~ -"'-" __....,._ 

~---v-----,-~ 3<>-L 

2 sec 

"LIGHT" ~~ LIGHT ---ON 

~--~~~~~~~~--~~~~~~~--

STIMULUS: 5o/sec2 for 18 sec 3o•L 2sec 

FIGURE 7. Tracings of nystagmus from a skater and a non-skater to a deceleration of 5°/sec' from 15 rpm (rotation was COW for GR, OW for HJ). 

Both "dark" and "light" trials are presented. Tracings are continuous for each condition. Vertical bars through the tracings demarcate the 

stimulus periods. Arrows indicate the onset of secondary nystagmus. Note the greater vigor and the earlier onset of the secondary response 

during "light" trials. 
...... 

f!:>. 

SKATER GH 

"DARK' -tw! Nv!if{/{(Vv'v'fV/1(/vv.-vtvVv' ;IVt!v~>'oi'V'V;'VVv"'v"" vvv,yvvv-~~ 

~~ ~-~·~~~,.,.L 2sec: 

II -t I ~i/1/'~,;V\...V~-------...-~ L "LIGHT ~ f 

'· ' ... \' ....., LIGHT ON 

r-.r-.._,~,.._,....__f"'J".....,......~'""" ~-

-~ 2 sec: 

NON-SKATER CL 

"DARK"~~~~ ~ 

~·~~ 

~~~-"""L 2 sec 

''LIGHT'' ~ 1(\1\P\ ,~~---t___._ ~-------- 1' I\~~ v----

LIGHT ON L ~Vl/V\/V~VVVvL,/VVVV,/1/" v~--3o• 

2 sec 

STIMULUS: 90°/sec for I sec 

FIGURE 8. Electronystagmographic tracings from a skater and a non-skater to a deceleration of 90° ;sec• from 15 rpm (rotation was OW for GH and 

COW for CL). Markings are the same as in Figure 7. 
I-' 

0"< 

0 

~ 

SKATER BN 

·~R( ~~~ 

~-------~~~ ----.~-~---------.r---

l ______ 3o· L 

2 sec 

11

LIGHT' -----

LIGHTS ON 

~~~ ~ 

~ 

~ 3~L STIMULUS: SOO/secl for I sec 2 sec 

FIGURE 9. Primary nystagmus was interrupted by a secondary response particularly rapidly in this subject during the "light" trial. Markings are the 

same as in Figures 7 and 8.