Cervical vestibular-evoked myogenic potentials in patients with multiple sclerosis: sensitive in detecting brainstem involvement?

Cervical vestibular-evoked myogenic potentials (cVEMPs) are accepted to demonstrate the vestibulo-collic reflex. However, the brainstem pathway is still not fully understood. The aim of the study was to evaluate the contribution of cVEMPs to detection of brainstem involvement in multiple sclerosis (MS). Thirty patients fulfilling the criteria for definite MS were included in the study. All were newly diagnosed cases, admitted due to an attack with active lesions on MRI. Thirty-one age- and sex-matched healthy controls constituted the control group. The latencies of peaks p13 and n23 and peak-to-peak amplitude of p13-n23 were measured. Brainstem lesions on MRI were present in 13 of the patients (43.4%). Comparison of the overall results recorded from patients with the healthy controls did not reveal a statistically significant difference in any of the parameters studied (p > 0.05). A significant inter-side difference was not also present between groups (p > 0.05). When p13 and n23 latencies exceeding 2.5 standard deviations (SD) were taken into consideration, it was seen that there were seven patients (23.3%) with prolonged latencies mainly involving the p13 peak. Five of them had brainstem signs on examination and had brainstem lesions on MRI. In the other eight patients with abnormal MRI, normal results were recorded indicating that in only 38% of patients with brainstem lesions, cVEMPs were altered. Absence of a correlation between cVEMPs and brainstem clinical or MRI lesions defies their role in identifying lower brainstem involvement.