Abstract
A 2-year and 7-month-old boy had developed ataxia and nystagmus since the age of 1 year and 4 months. Hemangioblastoma was removed from the left cerebellar tonsil at the age of 1 year and 5 months.
Electronystagmography revealed that horizontal nystagmus changed its direction alternately with the period of approximately 90 seconds including a 20-second rest period. Characteristic was the nature that for forward gaze his head was rotated to the direction of the quick phase and was maintained in its direction during the nystagmus to the same side (Fig. 2). The direction of the head rotation shifted to the opposite side following change in the direction of nystagmus. The nystagmus disappeared at the age of 3 years and 11 months. Our findings may support the theory that the lesion responsible for periodic alternating nystagmus is in the cerebellum.
