To evaluate upright balance function, we examined 50 normal subjects and 11 patients with vestibular disorders using computerized dynamic posturography (EquiTest System). The normal range was determined from the results of tests of normal subjects. Under sway-referenced support conditions (conditions 4, 5, 6) nine patients (81.8%) showed abnormal test results. However only two patients (18.2%) with vestibular neuronitis revealed abnormal equilibrium scores under fixed support conditions (conditions 1, 2, 3). Somatosensory input appears to be very important in the maintenance of upright balance.
