TELEMETERING OF EYE AND HEAD MOVEMENTS IN BALLET ROTATION

抄録

A 4-channel radio-telemeter, capable of transmitting eye and 3-dimensional head movements, was devised and eye and head movements in ballet rotation were observed. The purpose of this study was to observe the mode of appearance of nystagmus during intentional movements, and to elucidate the role played by vestibulo-ocular reflexes in intentional movements.
1. In observations of "tours chaînés" the appearance of one-beat nystagmus per rotation was recognized. This kind of nystagmus was produced by ballet dancers intentionally by means of jerking movements of the eye and head, i.e., spotting. The multiple irregular perrotatory nystagmus appearing during passive rotation was suppressed in ballet rotation by intentional spotting technique. That is, the will controlled reflexes.
2. In the record of beginners' "tours chaines, " multiple irregular nystagmus was recognized. That is to say, the ability to intentionally control perrotatory nystagmus appearing reflexly was acquired through training.
3. The one-beat-per-rotation nystagmus appearing in ballet rotation. was analyzed in terms of head movements in "pirouette rotation". As a result it wast found, that this intentional eye movement was a motion to coordinate with the vestibulo-ocular reflexes provoked by jerking head movements such as spotting. In other words, intentional movements were carried out by the use of reflexes.
4. Postrotatory nystagmus in "fouette en tournant" was observed. When the eyes were kept open after rotation, postrotatory nystagmus was not observed, but when the eyes were closed after rotation, active nystagmus appeared. The suppression of postrotatory nystagmus in ballet rotation is largely due to visual fixation.