Oscillopsia and vertical eye movements in Tullio's phenomenon.

BACKGROUND

Pure tones stimulated oscillopsia in a 30-year-old man with bilateral hearing loss and Tullio's phenomenon.

DESIGN

The subject's eye movements were recorded with electro-oculography while he was seated with his head stabilized facing a visual array. Pure tones were given in each ear, individually, from 500 to 2000 Hz, 90 to 110 dB. The subject reported the intensity of oscillopsia, if any, during each trial. He was also tested while standing on a force platform and receiving pure tones.

RESULTS

No increased postural sway was found, but oscillopsia and vertical eye movements followed stimulation to the more impaired ear.

CONCLUSIONS

These results support the hypothesis that Tullio's phenomenon is caused by inner ear pathology and suggest that oscillopsia is caused by the occurrence of unplanned vertical eye movements, the perceptual consequences of which were unexpected.