Sudden hearing loss as a presenting symptom of acoustic neuroma

Purpose: Retrocochlear pathological findings may be suggested by findings o n the brainstem response and acoustic sensorineural reflex (AR) tests. We d escribe the incidence of acoustic neuroma presenting as sudden hearing loss (SHL) and the effectiveness of the discrimination (DISC) test, the brainst em-evoked response, and AR test in predicting acoustic neuroma in patients with SHL. Methods: We retrospectively reviewed the charts of all adult patients who p resented to our center with sensorineural SHL between 1989 and 1995. Two gr oups were defined: those with cerebellopontine angle (CPA) tumor and those with negative imaging findings. Results of the brainstem-evoked response, A R, and DISC tests were compared. Results: Forty patients were admitted with sensorineural SHL, of whom 19 (4 7.5%) had a CPA tumor. The latter group showed a significantly lower mean a ge and better results for the low frequencies on pure tone audiometry, as w ell as better brainstem-evoked response test results than the patients with negative imaging findings. There was also a significant difference between the groups for both the affected and unaffected ears on the discrimination test. Conclusion: Acoustic tumors may be a more common cause of sudden sensorineu ral hearing loss than previously suspected. The DISC test is a useful scree ning tool for acoustic tumor, whereas the brainstem-evoked response test sh ows poorer results in affected patients with sensorineural hearing loss tha n in other subgroups with different signs of acoustic neuroma. We recommend that young patients presenting with mild SHL who have normal results on th e AR and brainstem-evoked response tests undergo magnetic resonance imaging to rule out CPA tumor. Copyright (C) 1999 by W.B. Saunders Company.