ASSESSMENT OF CERVICAL AND OCULAR VESTIBULAR EVOKED MYOGENIC POTENTIALS IN MULTIPLE SCLEROSIS PATIENTS

Abstract

Background: Multiple sclerosis (MS) is a chronic neurological disease affecting the central nervous system and is the leading cause of disability due to brainstem affection. Cervical Vestibular Evoked Myogenic Potentials (cVEMPs) are a clinical demonstration of vestibulo-colic reflex which descends via the vestibulospinal tract through the lower brainstem while ocular VEMPs (oVEMPs) represent vestibulo–ocular reflex which ascends via the Medial Longitudinal Fasiculus through the upper brainstem.Aim: To assess cVEMPs and oVEMPs in MS patients with and without brainstem lesion(s) compared to normal controls.Patients and Methods: All subjects underwent history taking of clinical symptoms and Expanded Disability Status Scale (EDSS) score, audiometric testing, 500 Hz toneburst air conduction cVEMPs and oVEMPs and brain MRI. Latency and amplitude of cVEMPs (P13, N23) and oVEMPs (N10, P15) were recorded in 10 healthy controls (20 ears), 10 MS patients (20 ears) with brainstem lesion(s) and 10 MS patients (20 ears) without brainstem lesion(s).Results: The cVEMPs and oVEMPs latencies in MS patients were significantly prolonged compared to controls. VEMPs latencies in MS with brainstem lesion(s) were significantly prolonged compared to patients without brainstem lesion(s). No correlation was found between the clinical state and VEMPs responses. A significant positive correlation was found between VEMPs latencies and EDSS in both MS subgroups.Conclusion: VEMPs are of value in detecting silent brainstem lesions through evaluation of upper and lower brainstem. The combination of oVEMPs and cVEMPs to MRI and the correlation with the disability state provide comprehensive evaluation of brainstem involvement in MS patients.