SHORT VESTIBULOOCULAR REFLEX TIME-CONSTANT IN COMPLETE UNILATERAL VESTIBULAR LESIONS

The time-constant of the vestibule-ocular reflex (VORtc) in response t o short accelerations was studied in 18 patients with complete unilate ral vestibular lesions: 12 patients with incomplete lesions and 9 heal thy controls. The marked group differences in VORtc, which was short i n patients with complete lesions and long (i.e., greater than or equal to 10 s) in the controls and some patients with incomplete lesions, s uggests the finding of a long VORtc in a patient with a unilateral ves tibular lesion to indicate the presence of an incomplete lesion. Moreo ver, one analytic method (where the initial phase of decay is weighted ) showed the VORtc to be ranger following stimulation toward the healt hy ear than following stimulation toward the lesioned ear, whereas oth er analytic methods showed no direction asymmetry in VORtc.