Follow-up of vestibular function in bilateral vestibulopathy

Objectives: Bilateral vestibulopathy (BV) is an often overlooked vestibular disease with various etiologies. Until now, only small case series have reported on the course of the disease. Our main goal was to determine the frequency and extent of recovery or worsening of vestibular function and their dependence on the etiology of BV.

Methods: 82 patients (59 males, 23 females; mean age 56.3±17.6 years) diagnosed with BV in our dizziness unit between 1993 and 2005 were examined in a follow-up study. All underwent a neuro-ophthalmological and neuro-otological examination and electronystagmography with caloric irrigation and measurement of the mean peak slow phase velocity (SPV) at the initial and follow-up investigation. All patients subjectively evaluated at the time of follow-up (1) the course of their diseases by comparing any changes in imbalance and gait unsteadiness and (2) the changes in their health-related quality of life with a self-classification system. Cranial MRIs were performed in 78 patients.

Results: The average follow-up time was 51±36 months. Overall, the statistical analysis of mean peak SPV of caloric-induced nystagmus revealed no significant change over time (initial SPV 3.0±3.5 degrees/s (deg/s) or at follow-up 2.1±2.8 deg/s). As regards the etiological subgroups, only caloric responses of patients with BV due to meningitis slightly increased at follow-up (initially 1.0±1.4 deg/s and at follow-up 1.9±1.6 deg/s); however, this was not significant. Vestibular outcome was independent of age, gender, time course of manifestation of BV (slowly progressively or sequentially with preceding attacks of vertigo), and severity of BV. Single analysis of each patient showed that caloric responses substantially improved by ≥5 deg/s in only two patients on both sides (idiopathic BV n=1, Sjögren's syndrome n=1) and in eight patients on one side (idiopathic n=6, meningitis n=1, Menière's disease n=1). Forty-three percent of the patients graded the course of their diseases as stable, 28% as worsened and 29% as improved. Eighty-four percent of the patients stated that BV impaired their health-related quality of life (42% slightly, 24% moderately, 18% severely).

Conclusions: Our data support the view that the prognosis of BV is less favorable than assumed. Vestibular function remains impaired or lost in the majority of these patients regardless of the etiology.