ing pirouettes performed in the laboratory. The
skaters were simply instructed to whirl them-
selves about in dancing spins within a circular
area about 5 feet in diameter. At a given
signal, they stopped abruptly. With eyes open,
2 or 3 beat’ of nystagmus were occasionally
noted immediately after the spin. With eyes
closed, vigorous nystagmic eye movements, as
in Figure 5, were consistently obtained.

ON-ICE PHASE

In the laboratory situation, the skaters pro-
duced strong vestibular responses in total
darkness while serving, for the most part, as
the passive recipients of vestibular stimulation.
On ice, however, the skaters actively induce
and control the sensory input by means of a
thoroughly practiced discipline which involves
psychological as well as physical factors. Four

of the skaters examined in the laboratory were
therefore tested during and following their
on-ice spins.

Methodology

Recording. The telemetry system used to
obtain tracings during the laboratory pirouettes
permitted the recording of eye-movements
during and after the skaters’ high velocity,
on-ice spins. The Telemedics RKG-100 telem-
etry system was utilized with a pair of
electrodes taped by the outer canthi. The
leads were plugged into the transmitter strapped
to the skater. The receiving system and the
recorder were located at rinkside. Motion
picture cameras employing both standard and
high speed film were used to obtain additional
information concerning the eye and body move-
ments of the skaters.

SKATER DA

AL FUL UA SM vrayinannnan ranean ener

SKATER AMF

A 8 A oom ene nnn

PIROUETTES: EYES CLOSED

Ficure 5, Nystagmus resulting from pirouettes performed by three figure

skaters in the

laboratory. Their eyes were closed throughout the trials. Vertical bars demarcate
the turning period. “ Each tracing represents 30 seconds of recorded activity.

—5-



indicated some possibility of directional differ-
ences in the skaters’ nystagmus favoring right-
beating responses. A larger sample of skaters,
quantification of nystagmus, and_ statistical
comparison with a non-skater group would be
required to establish these relations.

The fact that clear turning sensations as well
as brisk nystagmic responses were obtained
from the skaters in darkness somewhat compli-
cates current views on the question of vestibu-
lar habituation. The data, however, support
our previous laboratory work in which repeated
caloric irrigations (Collins, 1965) and repeated
angular accelerations (Collins, 1964) did not
result in a severe reduction or abolition of nys-
tagmus in ordinary subjects; some response
decline occurred (approximately 30% reduction
in slow-phase displacement) but, in alert sub-
jects, increased vestibular activity (greater
number of nystagmus beats) was concomit-
antly present under some conditions (Collins,
1964; 1965). Two hundred unidirectional
angular accelerations in darkness also did not
abolish sensations of angular displacement in
ordinary subjects, although a 35-40% decline in
this response was obtained (Collins, 1964). It
would seem that, when the lateral semicircular
canals are held rigidly in the plane of rotation,
some initial decline in the magnitude of the
slow-phase sweep of the eyes may occur, but
repeated stimulation will not result in complete
suppression of nystagmus or of the sensation of
angular motion in the absence of visual stimuli.
The form of the nystagmic response may
change, however, and such a change (lower
amplitude, higher frequency nystagmus) may
still be evident after one month without stimu-
lation (Collins, 1964).

Summary

Several professional figure skaters who, as
part of their daily routine, subject themselves
to strong semicircular canal stimuli, were given
a series of laboratory tests consisting primarily
of caloric irrigations and mild angular
accelerations. Brisk nystagmus and clear
turning sensations were consistent findings in

total darkness. Motion pictures and telemetered
eye-movement recordings were then obtained
during and following the skaters’ normal spins
on ice. Mean peak velocities of 235-278 rpm
were achieved by four of the skaters. Vigorous
nystagmus and dizziness or turning sensations
occurred following spins when visual fixation
was not permitted. Loss of equilibrium and
disorientation also occurred when the skaters
attempted to maneuver after their spins with-
out visual cues. The notion that complete
suppression of vestibular responses occurs in
figure skaters as a result of their repeated ex-
posure to high velocity angular accelerations
is not upheld by the present data.

Acknowledgment

Grateful acknowledgment is made of the
technical assistance rendered by Tarea Lee,
Billy P. Updegraff, Ruth Ann Crain, Kathryn
Quattlebaum, and Mary Ellen Allen during
various phases of this study, and to F.F. Winters
for motion picture photography and William
Geyer for still photographs. Special thanks are
due to the management of Ice Capades, Inc.,
to Ice Capades skaters Doug Austin, Ann-
Margreth Frei, Per Larsen, Gabrielle Weidert,
and Aja Zanova and to professional skaters Jinx
Clark, Phil Richards and Ronnie Robertson for
their complete and cheerful cooperation.

References

Collins, W. E.:  Task-Control of Arousal and the Effects
of Repeated Unidirectional Angular Acceleration on
Human Vestibular Responses, Acta Otolaryngol. Suppl.
190, 1964,

Collins, W. E.: Subjective Responses and Nystagmus Fol-
lowing Repeated Unilateral Caloric Stimulation. Ann.
Oto—, Rhino Larrngol., 1965 (in press).

Guedry, F. E.: Psychophysiological Studies of Vestibular
Function, In Neff, W. D. (Ed.): Contributions to
Sensory Physiology. N.Y., Academic Press, 1965, vol. 1,
pp. 63-135.

McCabe, B. F.: Vestibular Suppression in Figure Skaters.
Trans. Amer. Acad. Ophthal. Otolaryngol., 64:264, 1960.

Mowrer, O. H.: The Modification of Vestibular Nystagmus
by Means of Repeated Elicitation. Comp. Psychol.
Monog., 9 (No. 43), 48 pp., 1934,


responses were of considerable duration (see
Figure 7), it is possible they may have been
attenuated, considering the magnitude of the
deceleration stimuli.

Disorientation. At the conclusion of spins
in which the lateral semicircular canals were
in the plane of rotation, and with eyes open,
all of the skaters walked straight forward with

no difficulty. Their ability to maneuver grace-
fully with open eyes is not surprising since their
skating routines require well-coordinated move-
ments after completing a spin. However, in
performing a “layover camel spin” (stimulating
vertical semicircular canals) and completing
the skating routine by spinning upright (there-
by adding stimulation of the lateral canals),

SKATER DA

LE flee eal ae oe
ee NW V nw

SKATER AMF

Dap P aS Ait gyi en me

ey

ml ptt fa
7

SKATER PL

Aol yf tally ail HA enna unre
Ein ay rey inn inn entAonnsionannrunennltn val,
SKATER GW
KAI OE ane a A A
MA ea a ae

EYES CLOSED

ON-ICE SPIN:

Ficune 7. Telemetered recordings of eye movement during on-ice spins performed by four
skaters with eyes closed immediately following the spin, Vertical bars demarcate
the spinning periods. Vigorous nystagmus was obtained in all cases. The two
arrows in AMF’s tracing” indicate the period during which she inadvertentl
rolled her eyes upward behind her closed lids; nystagmus quickly, disap
When told to center her eyes (second arrow), still behind closed lids, nystagmus
recommenced. The several seconds of unclear eye movements following the spin
in DA’s tracing may also have been due to upward rolling of the eyes. For each
skater, a total of 50 seconds of recorded activity is presented.

-7-



Procedure. The skaters were asked to
perform their usual on-ice spins (which place
the lateral semicircular canals in the plane of
rotation) and, upon stopping, to orient them-
selves toward the-cameras. The skaters then
either fixated on the cameras or lightly closed
their eyes. Several other types of spins (e.g.,
camel, layover camel) were also performed.
Motion pictures and ‘electronystagmographic
recordings were obtained.

During a second on-ice session, the skaters
were asked to again perform the spins and,
upon facing the cameras at the conclusion of
each spin, to walk straight forward. The walk-
ing on skates was performed under “eyes open”
and “eyes closed” conditions.

Results

Vestibular Nystagmus. At the conclusion of
their spins, with eyes open, all of the skaters
had a brief nystagmus which was quickly
inhibited by visual fixation (see Figure 6).
Only one subject (DA) reported blurred vision
during this time and his nystagmus was con-
sistently more pronounced and of longer
duration than that of the other skaters.
(Skater AZ, tested only in the laboratory, re-
ported that her vision blurs upon stopping from
an on-ice spin and is frequently still blurred as
she begins her next skating movements.) With
eyes closed at the end of their spins, vigorous
nystagmic eye movements were uniformly
obtained from the four skaters. Although these

UT MALIN ASL

SKATER AMF

Nps ACA et

SKATER PL

Praha MA, plana, perenne

SKATER GW

re LT et

ON-ICE SPIN: EYES’ OPEN

Ficure 6. Eye-movement recordings obtained by means of telemetry during on-ice spins

performed by four skaters with eyes open. Vertical

bars demarcate the spinning

periods. Several clear beats of nystagmus appear at the end of each spin. The

noisy records for PL are due to his tendeng

sy to squint his eyes. Each tracing

represents 30 seconds of recorded activity.

-~6—


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‘uyds oy jo worpenp om ut pue premdn peoudsrp oq 0) swodde osps sake nour,
“VG, Pu TW JO seovy oy} UF WUeprAe ore uojsue} pue uoMOIG ‘suds Heyy
yo Ayoopen yeod ayy poyover Aowy se aye) vq pue ‘MO ‘ANY Jo sydexBajoyg “g sunory



AM-65-24

ADAPTATION TO VESTIBULAR DISORIENTATION:
Il. NYSTAGMUS AND VERTIGO FOLLOWING
HIGH-VELOCITY ANGULAR ACCELERATIONS

William E. Collins, Ph.D.

Approved by Released by
Stambe R euHlehlLes W/ b Whee
Stantey R. Mouzer, M.D. M. S. Ware, M.D.

Dmecror, CARI Feperat Arr SuRcEON

September 1965

FEDERAL AVIATION AGENCY
Office of Aviation Medicine
Civil Aeromedical Research Institute
Oklahoma City, Oklahoma



subject GW experienced some dizziness and
staggered slightly while attempting to walk
with eyes open.

With eyes closed after completing a spin, all
of the skaters had walking difficulty. In fact
PL, the first skater to attempt ambulation with
closed eyes, went into a tight turn to his left
after just a few steps and fell to the ice. It is of
interest that the skaters anticipated no diffi-
culty in maneuvering with eyes closed after
spinning and were quite unprepared for the
lack of control, disorientation, and dizziness
which they experienced. Three of the skaters
(DA, AMF, and PL) were clearly staggering
or falling to their left during attempted forward
movement. GW, however, consistently stag-
gered to her right and reported feeling com-
pelled to move in that direction. It should be
noted that this “walking task” consisted of
ordinary stepping movements and was not the
more difficult heel-to-toe walk frequently em-
ployed to test equilibrium.

All of the skaters tested on ice performed
their spins in the usual counterclockwise direc-
tion. (Apparently relatively few skaters spin
habitually in a clockwise direction. Of the 8
skaters examined in this study, only RR is a
clockwise spinner.) In attempting clockwise
spins the skaters could not perform at any-
where near the level of proficiency which they
demonstrated in their usual turning direction.
In addition, with eyes closed, they appeared to
experience more dizziness from these milder
stimuli (slower and fewer turns), and kept a
spread stance for a longer period of time after
the spin to maintain balance.

It is clear that the skaters do not use the
“spotting” technique employed in dancing
spins. Not only is their angular velocity too
high to permit “spotting,” but the skaters dem-
onstrated their ability to spin with eyes closed.
Thus, they require no visual reference (such
as a blurred line of footlights) to assist them
in maintaining balance; apparently propriocep-
tive and kinesthetic signals are sufficient.

Analysis of High-Speed Film. Twelve spins
were recorded on high-speed film. Analysis of
the film indicated that peak spinning velocities
ranged between 226-289 rpm. Mean peak
velocities were 235 rpm for DA, 258 rpm for
PL, 268 rpm for GW, and 278 rpm for AMF.
It is to be noted that, during these filmed se-

quences, the skaters were not necessarily at-
tempting to achieve a maximum velocity, that
they were wearing the telemetering transmitter,
and that since the testing schedule called for a
total of 10-20 spins per subject, fatigue may
have been an additional factor affecting the
peak values on those spins which were photo-
graphed. It is clear, however, as McCabe
(1960) has noted, that the skaters regularly
achieve spinning velocities between 250-300
rpm.
The high-speed film also showed some effects
of such rapid angular motion on the skaters.
Some of these changes are evident in Figure 8.
During spins, the skaters’ eyes tend to roll up-
ward and the lids are sometimes partly closed
(see also McCabe, 1960). For 3 of the skaters,
the eyes seemed to be displaced, for the most
part, in the direction of the spin. The single
exception (GW) appeared to have her eyes
displaced in the direction opposite the spin.
In addition to considerable bodily tension, the
high spinning velocities produced facial dis-
tortion in all of the skaters; their cheeks tended
to pull away from the skull and blood was
drawn to the extremities, causing a clearly ob-
servable reddening of the nose.

General Discussion

The present data indicate that there is no
total suppression of vestibular responses from
figure skaters as a consequence of repeated,
high-velocity, angular motion. Without op-
portunities for visual fixation, both in the labor-
atory and on ice, all of the skaters gave brisk
nystagmic reactions to angular accelerations. In
addition, clear sensations of angular motion
were experienced in the laboratory to mild
rotatory stimulation. However, the skaters ap-
pear to have learned to reduce vestibularly-
induced ocular movements to some extent by
means of visual fixation. This ability to exert
some visual control over the effects of vestibular
stimulation may account for Mowrer’s (1934)
observation and McCabe’s (1960) report that
skaters showed either “distinctly subnormal”
responses or no nystagmus at all. It is even
possible that nystagmic responses of the skaters
in total darkness may differ in some ways, on
the average, from responses of ordinary sub-
jects and, in addition, our laboratory data

—8—


that the lateral semicircular canals were in the
plane of rotation.

Recording. Electrodes were taped by the
outer canthi of the eyes to permit recording of
horizontal components of eye movements. An
indifferent electrode was located on the fore-
head. Offner T and TC recording systems
were used. For the two subjects (JC and PR)
who were exposed only to unilateral 30° C
calorics, DC records were obtained. In all
other cases, a 3-sec RC time constant was used.

Telemetry. For some tests, subjects per-
formed pirouettes in the laboratory. To record
eye movements during and following these body
movements, a Telemedics RKG-100 telemetry
transmitter and receiver were used to pick up
the eye movement signals and feed them into
the recorder. Use of the telemetry equipment
reduced the time constant in the recorder to
approximately 1 sec.

Results

Caloric Irrigations. All of the skaters were
given unilateral caloric irrigations. With eyes
open in a lighted room and visual fixation on an
object (motion picture camera) located ap-
proximately 2 feet away, nystagmus was not
vigorous; in one subject it was almost unde-
tectable. Eye closure resulted in an accentuated
response. When tested with eyes open in total
darkness, nystagmic tracings from the skaters
to both unilateral (Figure 1) and bilateral
(Figure 2) stimuli showed brisk nystagmic eye
movements.

Subjective responses to calorizations in total
darkness varied considerably. Five skaters in-
dicated no sensation or vague experiences (such
as rocking motions or “headiness”) to unilateral
stimuli. The remaining 3 skaters (JC, PR, RR)
reported definite turning sensations, although
one of these (PR) reported motion to the left

EAR SKATER AZ

RIGHT

tye fone, bd pol NA Baal atl yO f AYE le

Wynter pton, port mm Yr lt Pot oned poberp hee fleets ttf lag te,

pirical pesanba td aptoeet OCA LON AB LL LNA ALL ODA AF

“be

STIMULUS: 30°C for 30 SEC
RIGHT De Ea wa tented an i neon Q/
AAA AY AW rn WAYS AN Veet

WN S \ arer n s,

toe

STIMULUS: 44°C for 30 SEC

SKATER PL

STIMULUS; 30°C for 30 SEC

STIMULUS: 44°C for 30 SEC

Ficure 1.

Responses of two figure skaters to unilateral caloric irrigations, Vertical bars

through the records indicate the point at which the stimulus ended. Eye-
movement calibrations appear at the end of each set of tracings. Tests were

conducted in total darkness,


ADAPTATION TO VESTIBULAR DISORIENTATION:
Il. NYSTAGMUS AND VERTIGO FOLLOWING HIGH-VELOCITY
ANGULAR ACCELERATIONS

In spite of a formidable and still growing
literature on the question of habituation of
vestibular responses (cf. Collins, 1964; Guedry,
1965), only Mowrer (1934) and McCabe (1960)
appear to have examined vestibular reactions
in figure skaters. In a footnote (p. 8), Mowrer
(1934) indicated that his studies of habituation
led him to test nystagmic reactions of a limited
number of professional skaters and ballet corps
members. He asked these individuals “to spin,
in characteristic manner, and permit...
(Mowrer) , . . to observe their eyes immedi-
ately afterwards. In many cases, there was no
detectable post-rotational nystagmus whatever.
In certain other cases, a noticeable (though
distinctly “sub-normal”) nystagmus was pres-
ent...” More recently, McCabe (1960) made
use of motion picture films as well as visual
observations in subjecting two highly proficient
figure skaters to ice water caloric irrigations,
Barany chair spins, tape walking, and on-ice
skating spins. He reported that “. . . Neither
vertigo nor nystagmus could be elicited by
stimulation of the vertical or horizontal canals.”

Electronystagmographic recording techniques
were employed in the present study and were
supplemented by motion picture films. A total
of 8 professional figure skaters were examined.
Six of these were given both rotary and caloric
laboratory tests and, of these, 4 were tested in
an “on-ice” phase of the study. Two additional
skaters were given caloric irrigations only.

LABORATORY PHASE
Methodology

Caloric Irrigations. Two water baths were
equipped with Bronwill constant temperature
circulators. Tubing from the base of each bath
terminated in its own plastic nozzle which
could be inserted into the external auditory
meatus. The temperature of the water at the
site of introduction to the ear was maintained
at 30° C from one bath and 44° C from the
other. Water flow was approximately 15 cc/
sec to permit ready monitoring of the stimulus
during administration in the dark. Duration
of unilateral stimulation (warm or cool water to
one of the ears) was 30 sec; that of bilateral
stimulation (simultaneous administration of
warm water to one ear and cool water to the
other) was 15 sec. Trials were conducted with
eyes open in total darkness, eyes open in illumi-
nation, and eyes lightly closed in illumination.

Angular Accelerations. Rotational stimula-
tion was provided by a Stille-Werner RS-3 ro-
tating chair. Both clockwise (CW) and
counterclockwise (CCW) rotations were em-
ployed. Stimuli ranged from 5°/sec’ to 15°/
sec’ and were applied for durations of 6 to 24
sec. A typical stimulus sequence consisted of
an acceleration (e.g., 5°/sec’* for 18 sec), 2 min
at constant velocity, and a deceleration of the
same magnitude as the acceleration. Subjects
were seated upright with heads positioned so

-1-