To Örebro University

Objectives: Vestibular Evoked Myogenic Potentials (VEMPs) are electric potentials, used as a parameter for the assessment of the otolith function. They can be recorded after sound stimulation with surface electrodes over each sternocleidomastoid muscle. The purpose of the study is to investigate VEMPs and correlate them with the electronystagmic findings in cases of Sudden HearingLoss (SHL).

Methods: Pure tone audiometry, acoustic immittance testing, caloric testing, Auditory Brainstem Responses and VEMP testing was performed on 34 patients with unilateral idiopathic SHL. Same testing was performed on a control group of healthy volunteers. VEMP responses were measured and compared to caloric responses.

Results: VEMPs were present in all normal subjects of the control group and ipsilaterally normal on the unaffected side in all patients with SHL. Twenty five out of 34 patients (73,53%) showed normal VEMP responses. In 13 patients both electronystagmographic findings and VEMPs were normal, but in 12 patients VEMPs were normal but there were abnormal caloric responses (canal paresis in 7 patients, spontaneous nystagmus in 5 patients). Nine patients displayed abnormal VEMPs (26,47%) on the affected side (in eight cases absent, in one case delayed) and eight of them demonstrated decreased caloric responses, while one patient had normal caloric responses.

Conclusions: In a considerable number of cases VEMPs were abnormal. However, most of the patients displayed normal VEMPs. Also, in the majority of patients, VEMPs correlated to the caloric responses, although in a certain number of cases either the superior or the inferior vestibular nerve was involved.