Vestibular compensation evaluated by rotation tests and posturography.

In patients with unilateral vestibular hypofunction (UVH), compensation plays an indispensable role in reorganizing and returning to normal the vestibulo-ocular reflex (VOR) and the vestibulospinal reflex (VSR). These compensatory and adaptive processes, however, may have an independent course because the results for VOR are nontransferable to VSR. Discordance between results of rotation tests (evaluating the compensation for the VOR) and posturographic (PG) results (evaluating compensation for the VSR) are observed in 50% of the patients with UVH. The complaint of "instability" shows correlation with abnormal PG data. Accordingly, a thorough evaluation of a patient with UVH has to include information about the VSR as it can be provided by PG.