The Inferior Vestibular Nerve and Posterior Canal BPPV

Abstract

Objective: The aim of the study was to learn whether normal ipsilateral cervical vestibular myogenic potential (cVEMP) responses, for which functional integrity of the inferior vestibular nerve is required, are present in all patients having the clinical picture of posterior canal benign paroxysmal positional vertigo (PCBPPV). Method: Twenty-four patients with PCBPPV participated in a prospective open study, conducted between November 1, 2009, and November 30, 2011. All had cVEMP after the completion of canal repositioning procedure. Follow-up 1, 3, 6, and 12 months after the initial treatment included the Dizziness Handicap Inventory (DHI) questionnaire and otoneurological bed-side examination. Results: Normal cVEMPs were recorded in 20 (83%) and were pathological in 4 (17%) subjects. The average DHI score in patients with normal cVEMP was 13.9 + 16.6 vs 0.7 + 1.1 among those with pathological cVEMP (N = 4 in the pathological VEMP group too small to allow statistical analysis). 14 (58%) patients had recurrent PCBPPV (rPCBPPV). Twelve (86%) of the subjects with rPCBPPV had normal and 2 (14%) had pathological cVEMP. The proportions of subjects having abnormal cVEMP did not differ significantly between the recurrence and non-recurrence groups (Fisher exact test). Conclusion: Most patients suffering from PCBPPV had normal cVEMP. Reduced symptomatology as quantified by the DHI score was found when the cVEMP was pathological. This finding suggests that functional integrity of the inferior vestibular nerve is required for the complete clinical picture of PCBPPV to take place.