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

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.