Subjective vertical and vestibular lesion

Patients with peripheral vestibular disorders may experience postural instability in the standing position, which means disorientation in their environment. The disturbed vestibular function in light reflects the postural instability in space. The present study investigates the relationship between the subjective vertical and the vestibular lesion. The subjects were patients with unilateral vestibular lesion, and the control subjects had no past history of vestibular lesion or any present vestibular lesion. A straight line consisting of 5 spotlights projected on a dome-shaped screen was concentrically moved like a stylus by pressing buttons. We measured the subjective vertical of the subjects using a 5-spotlight straight-line (spotlight-line) on a dome-shaped screen in front of which the subjects were placed. The result showed that the patients with unilateral peripheral disorder had a statistically significantly larger deviation to the impaired ear side, especially when the spotlight-line was moved from the impaired side, as compared with controls.