Objective: To search for distinctive clinical features of patients with double tinnitus in a single ear. Design retrospective: Study sample: Six hundred and fourteen tinnitus patients were interviewed using a detailed questionnaire. They underwent thorough audiological evaluation. Records of seven patients reporting double tinnitus in 10 ears were identified and analysed. There were three women and four men in the group (mean age 40, range 29-49 years).
Results: All but two individuals declared sudden onset of the complaints. Three patients had been diagnosed with sudden sensorineural hearing loss. In all the patients, the components of double tinnitus were compared both to a pure tone and to a narrow band noise. The sounds were considered by the patients to be primary (more prominent) or secondary. All but one patient declared hypersensitivity to loud sounds. Vertigo was present in only two of the double tinnitus sufferers. Abnormal DPOAEs frequency values and audiogram notch frequencies were closer to the primary than the secondary tinnitus matches.
Conclusions: In our study, double tinnitus was rare, mostly perceived by patients with a sudden onset of tinnitus. This is the first report presenting audiological findings in patients with double tinnitus in a single ear. Prospective search of cohorts of tinnitus sufferers for such patients and functional neuroimaging of their auditory pathways for determining underlying mechanisms of the complaints is advocated.
Keywords: Tinnitus; hearing; loudness matching; minimum masking level; pitch matching.