Central Compensation of Central Vestibular Lesions

Background: Peripheral and central vestibular lesions cause a vestibular tone imbalance, that is centrally compensated. Whereas the central compensation of peripheral vestibular lesions has been studied in detail, little is known about central compensation of central lesions. The subjective visual vertical (SVV) – as a component of the ocular tilt reaction – is a useful psychophysical parameter to measure central compensation for two reasons: first, it deviates in most acute peripheral and central vestibular lesions and, second, it normalizes over time despite persisting vestibular deficits. Objective: To determine the time course and degree of central compensation of central vestibular lesions by measuring the deviation of the SVV and to compare these values with those of peripheral lesions in a retrospective study. Methods: 50 patients with Wallenberg's syndrome (as a model for a central vestibular lesion) and 39 patients with vestibular neuritis (as a model for an isolated peripheral vestibular lesion) were examined. SVV was determined during at least two points of time within the first month after symptom onset. Results: The mean displacement of SVV was 10.6° in Wallenberg's syndrome and 10.5° in vestibular neuritis within the first days after onset of symptoms. SVV deviation within the last days of the observation period was averaged at 4° in the former and 3.1° in the latter group. Wilcoxon's rank sum test for matched pairs revealed a significant decrease of the deviation over time in both groups. Although the regression had an exponential character in both groups, the statistical power of individually fitted regression curves (ANOVA) was too low to perform a statistical comparison. Conclusions: We demonstrated that central compensation of a central vestibular lesion has a degree and time course similar to that of a peripheral vestibular lesion. These data provide the basis for a prospective study, which will determine the SVV and ocular torsion over a period of three months.