DECREASED SOUND TOLERANCE (DST): PREVALENCE, CLINICAL CORRELATES, AND DEVELOPMENT OF A DST ASSESSMENT INSTRUMENT

Abstract

DECREASED SOUND TOLERANCE (DST): PREVALENCE, CLINICAL CORRELATES, AND DEVELOPMENT OF A DST ASSESSMENT INSTRUMENT By Therese Verkerke Cash, M.S. A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Virginia Commonwealth University Virginia Commonwealth University, 2015 Major Director: Scott R. Vrana Professor of Psychology Department of Psychology Decreased sound tolerance (DST) conditions, including misophonia and hyperacusis, are emerging clinical conditions in behavioral medicine. Misophonia involves an extreme emotional response (often anger, disgust, or annoyance) to specific sounds (such as people chewing, swallowing, tapping their foot on the floor, etc.), while hyperacusis is defined by high sensitivity to sounds below normal sound sensitivity thresholds. Although research on these DST conditions is increasing, clearly defined prevalence rates, associations with other mental health conditions, and development of assessment tools that can identify and differentiate DST symptoms are needed. Research and clinical reports also suggest that DST problems are more likely to occur in individuals affected by tinnitus, and that drawing upon a bio-psychosocial conceptualization of tinnitus and other behavioral medicine conditions may be useful in understanding and treating DST conditions. This cross-sectional survey study was administered to college student (N=451) and community adult (N=375) samples and investigated DST prevalence rates, clinical correlates, and risk factors and mechanisms of action for misophonia and hyperacusis. In addition, the study developed and validated a new scale to identify misophonia and hyperacusis type sound sensitivity. Nearly 35% of individuals surveyed reported some degree of general auditory sensitivity, with 15-63% endorsing misophonia symptoms, and 17-26% endorsing hyperacusis symptoms, with rates depending on assessment method. Moderate to strong correlations were found between DST conditions and other mental and physical health conditions, including obsessive compulsive disorder, autism-spectrum traits, anxiety, depression, social phobia, medical conditions, and somatic and neurobehavioral symptoms. Mediation models revealed that the process by which misophonia symptoms become clinically significant and functionally impairing is partially mediated by amplification of bodily sensations and anxiety sensitivity. Risk factors for functional impairment related to misophonia symptoms were identified in moderation analyses and included neuroticism, synesthesia, and sensory sensitivity. An assessment instrument, the DST-10, and its subscales the Loudness Sensitivity Scale and Human Sounds Scale, was subjected to exploratory and confirmatory factor analysis and initial evidence for construct validity was demonstrated. This study was the first to assess hyperacusis, misophonia, and tinnitus rates in large general population samples and provides initial support for conceptualizing DST problems as behavioral medicine conditions.