Sudden deafness in vertebrobasilar ischemia: clinical features, vascular topographical patterns and long-term outcome.

The aim of this study is to document the clinical features and natural history of sudden deafness associated with vertebrobasilar ischemia (VBI) and to describe the vascular topographic patterns of ischemic lesions on brain MRI associated with sudden deafness based on data collected from a prospective acute stroke registry. From 364 consecutive cases of VBI diagnosed by clinical features and brain MRI between January 2000 and September 2003, 29 patients were identified as having sudden deafness as a symptom of VBI. In our series, the incidence of sudden deafness following VBI is 8.0% (29/364). Hearing loss occurred unilaterally (n=27) or bilaterally (n=2). All but one had vertigo as an associated symptom. Nine patients (31%) presented with an isolated audiovestibular loss initially and subsequently had delayed neurological deficits. Nearly a half of patients (14/29: 48%) showed cochlear features of hearing loss. Seventeen (81%) of 21 patients who were followed for at least 1 year after onset of sudden deafness had a recovery of hearing partially (n=10) or completely (n=7). The improvement rate of hearing loss in patients with profound hearing loss was significantly lower than that in patients with less than profound hearing loss (40% vs. 89%, P<0.01). In addition to infarction in the territory of anterior inferior cerebellar artery (n=23), cerebellar infarction in the territory of the medial branch of posterior inferior cerebellar artery (n=4) or an isolated brainstem infarction (n=2) was also associated with sudden deafness. An isolated sudden deafness with cochlear audiometric features can be the initial presentation of VBI. Sudden deafness due to VBI often has a good outcome. There is topographic heterogeneity of ischemic lesions on brain MRI in patients with sudden deafness due to VBI.