The Role of Vestibular Function Tests in Patients with Sudden Sensorineural Hearing Loss Who Have Subclinical Vestibular Dysfunction

Abstract

Background and Objectives The evaluation of vestibular function is very important for patients with sudden sensorineural hearing loss (SNHL) as it is a well-known prognostic factor. The purpose of this study was to evaluate subclinical vestibular dysfunction (SVD) and its association with prognosis in sudden SNHL patients with and without dizziness using the vestibular function tests. Subjects and Method Seventy eight patients who had been diagnosed with unilateral sudden SNHL were examined by dividing them into three groups according to their clinical findings such as vestibular function and subjective symptoms: 1) normal, 2) SVD and 3) dizziness. Vestibular dysfunction and hearing recovery rates were also assessed. Results Patients with SVD accounted for 62.5% of patients even though they did not complain subjective dizziness. The extent of vestibular dysfunction in the dizziness group was greater than that in the SVD group (p=0.05). The hearing recovery rates for normal, SVD and dizziness group were 72% (13/18), 57% (17/30) and 48% (12/25), respectively. The incidence and extent of vestibular dysfunction was greater in patients with severe hearing loss than in those with moderate to severe loss. A significant correlation was noted between hearing recovery rate and vestibular evoked myogenic potential (VEMP) testing. Normal and abnormal VEMP data were associated with good and poor recovery (p=0.001). Conclusion The evaluation of vestibular function is important in sudden SNHL patients with dizziness; however, SVD also explains a significant proportion of sudden SNHL in the absence of dizziness. Notably, VEMP is useful tools for evaluating prognosis of sudden SNHL.