Utricular Dysfunction in Refractory Benign Paroxysmal Positional Vertigo

Abstract

Objective To determine the prevalence of otolith dysfunction in patients with refractory benign paroxysmal positional vertigo (BPPV). Study Design Unmatched case control. Setting Tertiary care institution. Subjects and Methods Patients included were diagnosed with BPPV, failed initial in-office canalith repositioning maneuvers (CRMs), and completed vestibular testing and vestibular rehabilitation (n = 40). Refractory BPPV (n = 19) was defined in patients whose symptoms did not resolve despite vestibular rehabilitation. These patients were compared with a control group of those with nonrefractory BPPV (n = 21) for results of a caloric test, cervical vestibular evoked myogenic potential (cVEMP), and subjective visual vertical (SVV). Results Forty-six of 251 patients failed initial treatment with in-office CRM. Forty patients met inclusion criteria. There was no significant difference between the cases (refractory BPPV) (n = 19) and controls (nonrefractory BPPV) (n = 21) in terms of age, duration of symptoms, laterality of BPPV, and BPPV symptoms. There was no difference in the prevalence of caloric weakness and cVEMP abnormalities ( P > .05), with odds ratios (ORs [95% confidence interval (CI)]) of having abnormal results among cases vs controls of 1.1818 (0.3329-4.1954) and 4.3846 (0.7627-25.2048), for caloric and cVEMP, respectively. Abnormal eccentric SVV was more prevalent in refractory BPPV cases (58%) than in controls (14%) ( P < .0072). The OR (95% CI) of having abnormal SVV was 8.25 (1.7967-37.8822) higher among patients with refractory BPPV than those with nonrefractory BPPV. Conclusion Patients with refractory BPPV are more likely to have abnormal eccentric SVV and thus underlying utricular dysfunction. This finding is important to take into account when designing rehabilitation strategies for patients with BPPV who fail CRM.