The prevalence and onset of gaze modulation of tinnitus and increased sensitivity to noise after translabyrinthine vestibular schwannoma excision

Objective: To determine the prevalence and timing of onset of gaze-modulated tinnitus and increased sensitivity to noise in patients who had undergone translabyrinthine excision of a vestibular schwannoma. Study Design: Retrospective questionnaire study. Setting: University hospital departments of audiology and neurotology. Patients: A cohort of 359 patients who had undergone translabyrinthine excision of a vestibular schwannoma in the period 1997 to 2003. Intervention: Translabyrinthine excision of a unilateral sporadic vestibular schwannoma. Main Outcome Measures: Patient reports and visual analogue scale measures of the timing of onset of gaze-modulated tinnitus and the presence, timing of onset, and persistence of increased sensitivity to noise after surgery. Results: Completed questionnaires were returned by 275 patients (77%), of whom 132 (48%) were men and 143 (52%) were women. Preoperative tinnitus was reported in 150 patients (55%). In 124 of these 150 (83%) the tinnitus persisted, and in 26 of 150 (17%) it abated. Of the 125 patients without preoperative tinnitus, 43 (34%) developed it postoperatively. In 167 (61%) patients of the total group of 275, postoperative tinnitus was reported. Gaze-modulated tinnitus was reported in 53 patients (19%). Somatic-evoked or -modulated tinnitus was reported in 38 patients (14%). In response to the question, "Did you notice being extra sensitive to noise after your operation?," 138 patients (50%) replied that they did. In 111 patients, this persisted. The onset of the modulation of tinnitus was distributed throughout the postoperative period, whereas the onset of increased sensitivity to noise was overwhelmingly in the first 2 months after surgery. Conclusion: Gaze modulation of tinnitus after vestibular schwannoma removal was identified in 19% of patients in this series. The onset data did not convincingly argue for any specific mechanism. The prevalence of increased sensitivity to noise is surprising and may represent central hyperacusis in response to unilateral deafferentation of the auditory system.