Clinical Features of Non-Lateralized Tinnitus

Abstract

BACKGROUND: We aimed to analyze and confirm the clinical features of patients with non-lateralized tinnitus and to identify clues that can be used in their management. METHODS: Data from 469 patients who visited a university hospital complaining of tinnitus between March 2020 and December 2021 were reviewed. The patients' medical histories, Tinnitus Handicap Inventory, Beck Depression Inventory, and numerical rating scale scores on tinnitus awareness, annoyance, loudness, and effect on life, audiological profiles, and quantitative electroencephalography findings were documented. RESULTS: Forty-nine (10.4%) patients had non-lateralized tinnitus. They were older and had a shorter duration of symptoms (13.91 +/- 34.16 months) than patients with bilateral tinnitus (duration: 39.15 +/- 80.82 months) (P <.05). The accompanying symptoms, Tinnitus Handicap Inventory scores, and numerical rating scale scores were not significantly different between the 2 groups (P >.05). Patients with non-lateralized tinnitus had worse hearing at 12 kHz on the left side than those with unilateral tinnitus. Hearing asymmetry was least common in non-lateralized tinnitus (n = 11/49, 10.4%), followed by bilateral tinnitus (n = 54/198, 42.2%) and unilateral tinnitus (n = 97/222, 47.3%) (P <.001). Regarding quantitative electroencephalography, there were significant differences in the absolute power of the theta, alpha, beta, gamma, and total frequency bands based on tinnitus lateralization (P <.001). CONCLUSION: Non-lateralized tinnitus can be perceived in elderly patients with symmetric and extended high-frequency hearing loss before habituation is achieved at an early stage of tinnitus. However, there was no difference in the questionnaire scores and accompanying symptoms; therefore, it may not be worth managing non-lateralized tinnitus separately from tinnitus in the ear.