Objectives: The aim was to assess the internal consistency and convergent and discriminant validity of a new questionnaire for hyperacusis, the Inventory of Hyperacusis Symptoms (IHS; Greenberg & Carlos 2018), using a clinical population.
Design: This was a retrospective study. Data were gathered from the records of 100 consecutive patients who sought help for tinnitus and/or hyperacusis from an audiology clinic in the United Kingdom. The average age of the patients was 55 years (SD = 13 years). Audiological measures were the pure-tone average threshold (PTA) and uncomfortable loudness levels (ULL). Questionnaires administered were: IHS, Tinnitus Handicap Inventory (THI), Hyperacusis Questionnaire (HQ), Insomnia Severity Index, Generalized Anxiety Disorder, and Patient Health Questionnaire-9.
Results: Cronbach's alpha for the 25-item IHS questionnaire was 0.96. Neither the total IHS score nor scores for any of its five subscales were correlated with the PTA of the better or worse ear. This supports the discriminant validity of the IHS, as hyperacusis is thought to be independent of the PTA. There were moderately strong correlations between IHS total scores and scores for the HQ, Tinnitus Handicap Inventory, Generalized Anxiety Disorder, and Patient Health Questionnaire-9, with r = 0.58, 0.58, 0.61, 0.54, respectively. Thus, although IHS scores may reflect hyperacusis itself, they may also reflect the coexistence of tinnitus, anxiety, and depression. The total score on the IHS was significantly different between patients with and without hyperacusis (as diagnosed based on ULLs or HQ scores). Using the HQ score as a reference, the area under the receiver operating characteristic for the IHS was 0.80 (95% confidence interval = 0.71 to 0.89) and the cutoff point of the IHS with highest overall accuracy was 56/100. The corresponding sensitivity and specificity were 74% and 82%.
Conclusions: The IHS has good internal consistency and reasonably high convergent validity, as indicated by the relationship of IHS scores to HQ scores and ULLs, but IHS scores may also partly reflect the co-occurrence of tinnitus, anxiety, and depression. We propose an IHS cutoff score of 56 instead of 69 for diagnosing hyperacusis.