The relationship between smooth pursuit and fixation suppression (FS) of the caloric response was investigated in 42 patients with neurological disorders. Three results were obtained. (1) In the pattern analysis of smooth pursuit, 26 patients showed corresponding results in FS and smooth pursuit. In fifteen patients (whose cerebellum was affected), both the FS and the smooth tursuit were abnormal. Eleven patients (whose cerebellum was less affected) showed a normal FS and a normal smooth pursuit. (2) The computer analysis of smooth pursuit was abnormal in patients with cerebellar disorder and SCD, and their FS was also very abnormal. (3) FS was intact with an abnormal smooth pursuit in 15 patients. The high rate of correspondence in the two tests in (1) and (2) strongly suggests that FS and smooth pur-siut are controlled by the same mechanism in the cerebellum. Result (3) points to the existence of a cancellation system which can cancel VOR in the absence of smooth pursuit.
