Generalized cerebral ischaemia caused by orthostatic hypotension induces rotatory vertigo due to objective vestibular dysfunction. The presence of orthostatic vertigo and nystagmus has an association with the duration of orthostatic intolerance.

A unilateral ICP lesion at the pontine level leads to the development of isolated AVS. However, a negative head impulse test and directional dissociation between OTR/SVV tilt and body lateropulsion may distinguish lesions involving unilateral ICP at the pontine level from those affecting other vestibular structures.