Vestibular Dysfunction in Patients with Enlarged Vestibular Aqueduct

Abstract

Objectives: Enlarged vestibular aqueduct (EVA) is the most common inner ear malformation. While a strong correlative relationship between EVA and hearing loss exists, its association with vestibular dysfunction is less well established. In this study, we characterize the vestibular phenotype in patients with EVA. Methods: This was a prospective, cross-sectional study of 106 patients with unilateral (n = 26) or bilateral (n = 80) EVA, defined as a midpoint diameter greater than 1.5 mm, who were referred or self-referred to participate in a study of the clinical and molecular analysis of EVA at the National Institutes of Health. We obtained a clinical history focused on vestibular dysfunction, and specifically asked about age of independent walking, history of vertigo, head tilt with vomiting, and clumsiness. Based on tolerance and availability, participants underwent videonystagmography (VNG), cervical vestibular evoked myogenic potentials (cVEMP), and rotary vestibular chair testing (RVT) to objectively assess their vestibular function. Results: Forty-five percent of patients with EVA reported vestibular symptoms. A total of 44% (28 out of 66) of those completing VNG testing had abnormal results, as defined by abnormalities in caloric, ocular motor, and positional testing. An increased number of vestibular symptoms is correlated with the presence of bilateral (rather than unilateral) EVA ( P = .008) and a history of head injury ( P < .001). Abnormal VNG results also correlated with a history of head injury ( P = .01). Conclusions: Vestibular dysfunction is common in patients with EVA. To our knowledge, this is one of the largest prospective EVA studies which specifically address the vestibular manifestations.