Comparison of otoacoustic emissions in tinnitus and hyperacusis in adults with normal hearing sensitivity.

OBJECTIVE: To investigate the effect of tinnitus and/or hyperacusis on distortion product otoacoustic emission (DPOAE) measures in adults with normal hearing thresholds from 0.25 to 8 kHz, while accounting for extended high-frequency (EHF) thresholds. DESIGN: A behavioural study consisted of comprehensive audiological assessment, validated tinnitus and hyperacusis questionnaires, DPOAE amplitudes and input/output (I/O) functions. STUDY SAMPLE: Data of 56 participants with normal hearing were included for the analysis. Participants were categorised into four groups: (1) without tinnitus or hyperacusis, (2) with tinnitus only, (3) with hyperacusis only, and (4) with both tinnitus and hyperacusis. RESULTS: The groups with tinnitus showed elevated EHF thresholds compared with those without tinnitus. DPOAE amplitudes were not significantly affected by tinnitus and/or hyperacusis status; however, they were significantly affected by EHF thresholds. Further, no appreciable differences in DPOAE I/O functions were found across groups. CONCLUSIONS: The reported non-significant differences in DPOAEs in individuals with tinnitus and/or hyperacusis do not support a peripheral mechanism or an interaction between peripheral and central mechanisms underlying tinnitus or hyperacusis. Our findings, however, suggest the need to assess basal cochlear function (e.g. EHF thresholds) for a better understanding of differences in DPOAE measures in tinnitus and/or hyperacusis.

An online survey study of the association between tinnitus and hyperacusis using validated questionnaires.

OBJECTIVE: To investigate the association between the highly comorbid tinnitus and hyperacusis conditions using standard questionnaires. DESIGN: A cross-sectional internet-based survey consisted of general demographic questions, questions about hearing and emotional status, Tinnitus Primary Function Questionnaire (TPFQ), and Hyperacusis Questionnaire (HQ). STUDY SAMPLE: Six hundred sixteen completed surveys were obtained primarily from students and staff in a large university. RESULTS: About 6% of the respondents could be classified as having hyperacusis based on the criterion of HQ scores ≥ 28 and had significantly increased odds of reporting having tinnitus (OR 10.11; 95% CI 3.76-35.3). Tinnitus severity (TPFQ) and HQ scores were correlated regardless of the hearing loss status. When predicting TPFQ scores, after controlling for demographic factors and affective states, hyperacusis status became an insignificant predictor. In contrast, both affirmative answers to having anxiety and depression, together with hearing loss status and tinnitus were significant predictors of HQ scores. CONCLUSIONS: Having hyperacusis did not appear to contribute significantly to tinnitus severity, but having tinnitus contributed to the likelihood of having hyperacusis. Our findings provide a nuanced view of how tinnitus and hyperacusis conditions co-occur and influence each other, which may be valuable to clinicians and researchers.