Spatial gaze stability under active high-frequency head oscillation after acoustic neuroma surgery

Spatial gaze stability under active high-frequency head oscillations was investigated in 31 patients after acoustic neuroma surgery. Whereas gaze stability upon rotation to the intact side was excellent during the entire time course after surgery, rotation to the affected side produced marked gaze disturbance at frequencies higher than 1.0 Hz, and did not recover even several years after surgery. The maximal oscillation frequency decreased in the patient group. Oscillopsia, being found in 20% of the patients, showed little correlation with gain value or maximal oscillation frequency. Long-lasting disturbances of active head oscillation, gaze stability and perception after unilateral labyrinthine loss may indicate persistent asymmetry of spatial orientation during high-frequency head movements.