Failure of gaze stabilization under high-frequency head oscillation.
Gaze functions under high-frequency head oscillations with large amplitudes were investigated in 12 normal subjects. Oscillation amplitude decreased as the frequency increased (31 degrees at 2 Hz to 11 degrees at 5 Hz on average). Maximum head velocity and acceleration were 170-200 degrees/s and 2,500-5,000 degrees/s2, respectively. At frequencies higher than 2 Hz, the mean ratio of eye amplitude to head amplitude reached high large values (1.2 at 2 Hz to 1.8 at 5 Hz, on average), whereas it dropped to extremely low values (0.5-0.6 at 3-5 Hz) in the 2 referred patients with bilateral labyrinthine loss. High ratio values, different from the previous reports, may result from a failure of compensation due to abnormally high-frequency and large head oscillations. The present study indicated that the frequency range of VOR influenced by gaze should correspond to that of daily-experienced oscillations, and that once head oscillations exceed the limit, compensation quickly deteriorates.
Takahashi
M
M
Department of Otolaryngology, Keio University School of Medicine, Tokyo, Japan.
Akiyama
I
I
Tsujita
N
N
D000328:Adult; D005133:Eye Movements; D005260:Female; D005403:Fixation, Ocular; D006257:Head; D006801:Humans; D008297:Male; D009068:Movement; D012027:Reflex, Vestibulo-Ocular