목적: In patients with progressive unilateral sensorineural hearing loss (USNHL), presence of ipsilateral cerebellopontine angle (CPA) tumor should always be ruled out. Considering slowly growing nature of most CPA tumors, we can surmise that patients with CPA tumor may have ipsilateral vestibular hypofunction without any symptom due to gradual central compensation. In this regard, this study aimes to investigate characteristics of CPA tumor and correlation with non-symptomatic unilateral vestibular hypofunction (UVH) in USNHL patients. 방법:From January 2013 to June 2014, 257 subjects with USNHL but without subjective dizziness underwent internal auditory canal or brain magnetic resonance imaging (MRI) at Seoul National University Bundang Hosital. All enrolled patients underwent pure tone audiometry, speech audiometry, and vestibular function tests including . UVH was diagnosed with when findings such as canal paresis ≥ 20%, postiive head-shaking nystagmus or head-impulse test were present. The diameter of CPA tumor was measured on axial view of MRI. 결과:Among 257 USNHL subjects, 52 (20.2%) were diagnosed with CPA tumor. Of 52 subjects with CPA tumor, 43 (82.7%) had UVH while only 31 of 205 (15.1%) had UVH in patients without CPA tumor (Chi-square test, p < 0.001). 결론:Based on significant assocation between the presence of CPA tumor and non-symptomatic UVH, the possibility of CPA tumor should be considered when USNHL patients without any vestibular symptom present with UVH. Adding to conventional auditory brainsterm response, VFT may be of diagnostic importance for CPA tumors in subjects with USNHL.