Resolved sudden hearing loss as a presenting symptom of retrocochlear lesion

Objective: To determine whether acoustic neuroma-induced sudden hearing loss is associated with hearing recovery and, if so, to characterize its clinical, audiometric and imaging manifestations. Methods: The files of 72 patients with sudden hearing loss evaluated between 1989 to 2001 were reviewed. All patients underwent pure tone audiometry, acoustic reflex and auditory brain revoked response (ABR) test. Magnetic resonance imaging (MRI) was performed followed by a second hearing test after one month. The findings were compared between patients with and without evidence of tumors on imaging, and between patients with tumors with and without recovery. Results: Twenty-five patients (35%) had a diagnosis of acoustic tumor. Of these, six (24%) recovered hearing after one month. Five of them had small intracanicular tumors and one had a small extra-canicular tumor. There was variability in the hearing loss. Five had a pathological ABR and one had normal ABR.