Silent Vestibulopathy in Asymmetric Hearing Loss Can Be a Sign of a Cerebellopontine Angle Tumor

Woongsang Sunwoo,Jae-Jin Song,Han Park,Ja-Won Koo,Yoonjae Song,Byung Choi,Yung Jeon

doi:10.3390/ohbm1010006

Abstract

The presence of an ipsilateral cerebellopontine angle (CPA) tumor should be ruled out in patients with asymmetric sensorineural hearing loss (ASNHL). Although many patients with CPA tumors have ipsilateral vestibular hypofunction, some of them do not experience dizziness even with ipsilateral vestibular hypofunction. We analyzed the incidence of CPA tumors among patients with ASNHL without subjective dizziness based on the presence of vestibulopathy. We hypothesized that a patient with silent unilateral vestibular hypofunction (UVH) is more likely to be diagnosed with a CPA tumor. Among 157 subjects who underwent MRI for ASNHL, those who did not have “subjective dizziness” were selected. All subjects underwent hearing and vestibular function tests. UVH was diagnosed if canal paresis ≥ 25%, positive head-shake nystagmus, or gain of head-impulse test < 0.8 were detected. The diameters of the CPA tumors were measured along the petrosal ridge on the axial plane of MRI. Among the enrolled subjects, 44 (28.02%) were diagnosed with a CPA tumor. The 37 patients (84.1%) with a CPA tumor had silent UVH, while only 33 of the 113 patients (29.2%) without a CPA tumor had silent UVH (chi-square test, odds ratio = 12.8, p < 0.001). Silent UVH in patients with ASNHL may be a sign of a CPA tumor.

Highlights

Asymmetric sensorineural hearing loss (ASNHL) is characterized by a binaural difference at more than one frequency
Of the 157 patients, cerebellopontine angle (CPA) tumors were identified in 44 patients (18 males and 26 females), and CPA tumors were absent in the remaining 113 patients (51 males and 62 females)
There were no significant differences in mean asymmetries of SNHL (MASNHL) within frequencies in the non-tumor group

Summary

Introduction

Asymmetric sensorineural hearing loss (ASNHL) is characterized by a binaural difference at more than one frequency. The etiological diagnosis of ASNHL is extensive, and a precise diagnosis can be elusive. ASNHL can be caused by cochlear disorders and injuries, including noise exposure and a retrocochlear disorder. Patients with vestibular schwannomas (VSs) present with ASNHL 85–97% of the time [1,2,3,4]. The possibility of an ipsilateral cerebellopontine angle (CPA) tumor should always be considered in patients with ASNHL. CPA tumors are benign, their growth may result in significant morbidity and mortality if left untreated. Earlier detection of these tumors has resulted in a smaller tumor size at the time of diagnosis, which has significantly reduced the morbidity of treating

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