Psychometric Properties and Factor Structure of a New Scale to Measure Hyperacusis: Introducing the Inventory of Hyperacusis Symptoms

Objectives: Despite increasing interest in hyperacusis and other disorders of auditory sensitivity, there is still a lack of valid, standardized assessment tools to measure symptom severity, treatment outcomes, and diagnostic differentiation. Accordingly, this study sought to create a new scale that is reliable, valid, brief, and easy to score with the purpose of filling this gap. Design: Original items were constructed through review of currently existing models of hyperacusis measurement, as well as qualitative data collected from professional audiologists and individuals reporting heightened audiological sensitivity with tinnitus. An initial 26-item scale yielded sound reliability and validity properties. Refinement based on review of initial data resulted in a 25-question second version with a maximum score of 100. A total of 450 completed survey protocols were analyzed from 469 refined Inventory of Hyperacusis Symptoms (IHS) administrations collected online, representing individuals from 37 countries with a mean age of 34.8 years. Results: Internal consistency reliability analysis yielded a Cronbach's of 0.93, indicating excellent reliability. Furthermore, the IHS showed sound convergent validity with established measures of quality of life, anxiety, and depression in bivariate correlation analysis of Pearson's r. Factor analysis revealed a dimensional structure containing five factors, which were designated psychosocial impact, emotional arousal, functional impact, general loudness, and communication. Analysis of variance between perceived global hyperacusis severity categories provided a preliminary framework for scoring thresholds. Although the level of hearing loss did not correlate with IHS scores, increased tinnitus symptoms were a significant factor in predicting hyperacusis distress and severity. Conclusions: These initial results demonstrated sound statistical properties of the IHS and usefulness as a hyperacusis measurement tool in research and clinical practice. Factor structure and scale dimensions allow for differentiation between subtypes of loudness, annoyance, fear, and pain based on responses to clusters of specific items within the dimensional factor structure of the scale, and may thus prove useful in clinical practice and research.