Vestibular Evoked Myogenic Potentials in Patients with Benign Paroxysmal Positional Vertigo

Aim: Vestibular evoked myogenic potentials (VEMP) are electric potentials that can be recorded after sound stimulation and are used as a parameter for the assessment of the otolith function. These potentials arise after stimulation of the saccule and they can be recorded with surface electrodes over each sternocleidomastoid muscle. The responses consist of one positive and one negative successive wave. Benign paroxysmal positional vertigo (BPPV) is believed to be caused by degenerative debris free-floating in the endolymph that during a head movement leaves the macula of the utricle and gravitates into one of the semicircular canals. The aim of this study was to record and analyze the VEMP in patients with BPPV and compare them with the results of their caloric responses.

Material and Method: In order to evaluate the saccular function, the VEMP test was performed in 12 patients with BPPV. The patients were also subjected to pure tone audiometry, auditory brainstem responses, and electronystagmography (ENG). Normal values were established using healthy volunteers.

Findings: Ten out of 12 patients showed normal amplitude. Eleven out of 12 patients showed normal latencies. In 1 elderly patient, latencies were abnormal but this was probably due to age. Five patients (41.6%) had abnormal findings on the caloric testing, mainly canal paresis. Finally, in 2 patients with abnormal VEMPs, ENG responses were normal.

Conclusion: In the majority of patients with BPPV, VEMPs were found to be normal, while ENG findings were abnormal in 41.6% of the cases. However, more patients should be studied in order to evaluate possible VEMP abnormalities.