Available online 30 January 2023

Tinnitus is a common disorder that affects hearing and social interactions.

Patients with tinnitus have reported hearing difficulties in noisy environments.

Tinnitus negatively impacts sound source localization in those with normal hearing.

It might also affect the processing of brain cues for sound source discrimination.

To determine whether tinnitus negatively impacts the accuracy of sound source localization in participants with normal hearing.

Seventy-five participants with tinnitus and 74 without tinnitus were enrolled in this study. The accuracy of sound source discrimination on the horizontal plane was compared between the two participant groups. The test equipment consisted of 37 loudspeakers arranged in a 180° arc facing forward with 5° intervals between them. The stimuli were pure tones of 0.25, 0.5, 1, 2, 4, and 8 kHz at 50 dB SPL. The stimuli were divided into three groups: low frequency (LF: 0.25, 0.5, and 1 kHz), 2 kHz, and high frequency (HF: 4 and 8 kHz) stimuli.

The Root Mean Square Error (RMSE) score of all the stimuli in the tinnitus group was significantly higher than that in the control group (13.45 ± 3.34 vs. 11.44 ± 2.56, p = 4.115, t < 0.001). The RMSE scores at LF, 2 kHz, and HF were significantly higher in the tinnitus group than those in the control group (LF: 11.66 ± 3.62 vs. 10.04 ± 3.13, t = 2.918, p = 0.004; 2 kHz: 16.63 ± 5.45 vs. 14.43 ± 4.52, t = 2.690, p = 0.008; HF: 13.42 ± 4.74 vs. 11.14 ± 3.68, t = 3.292, p = 0.001). Thus, the accuracy of sound source discrimination in participants with tinnitus was significantly worse than that in those without tinnitus, despite the stimuli frequency. There was no difference in the ability to localize the sound of the matched frequency and other frequencies (12.86 ± 6.29 vs. 13.87 ± 3.14, t = 1.204, p = 0.236). Additionally, there was no correlation observed between the loudness of tinnitus and RMSE scores (r = 0.096, p = 0.434), and the Tinnitus Handicap Inventory (THI) and RMSE scores (r = −0.056, p = 0.648).

Our present data suggest that tinnitus negatively impacted sound source localization accuracy, even when participants had normal hearing. The matched pitch and loudness and the impact of tinnitus on patients’ daily lives were not related to the sound source localization ability.

Sound source localization

Tinnitus

Tinnitus handicap inventory

© 2023 Published by Elsevier Editora Ltda. on behalf of Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial.