Nystagmus Based Screening System for Vestibular Schwannoma in Patients With Asymmetric Hearing Loss

Abstract

Background and Objectives We conducted this study to propose a nystagmus based screening system (NBSS) for detecting vestibular schwannoma (VS) in patients with asymmetric sensorineural hearing loss (ASNHL).Subjects and Method Data of 90 patients diagnosed with VS were retrospectively analysed. For the 1:1 allocation, 90 ASNHL patients who were not diagnosed with VS were sequentially enrolled as the non-VS group and retrospectively analysed. Every participant received pure tone audiometry (PTA), a bedside vestibular function test, and magnetic resonance imaging. A total of 122 patients who passed the exclusion criteria were selected for the study.Results The sensitivity and specificity of the abnormal criteria of auditory brainstem response (ABR) for the detection of VS in patients (n=70) showing analyzable wave response were 80.0% and 52.0%, respectively. However, when we included all of the patients (n=122) who did not show analyzable wave response in ABR, the sensitivity and specificity of the abnormal criteria decreased to 34.8% and 68.4%, respectively. NBSS is composed of vertical spontaneous nystagmus, direction changing gaze evoked nystagmus, ipsilesional monophasic type head shaking nystagmus (HSN), and ipsilesional to contralesional biphasic type HSN. The sensitivity and specificity of the NBSS were 56.5% and 82.9%, respectively.Conclusion NBSS may be used as a supplementary test to ABR in detecting VS of ASNHL.