Hyperacusis : Clinical Studies and Effect of Cognitive Behaviour Therapy

Abstract: Hyperacusis is a type of decreased sound tolerance where the individual has decreased loudness discomfort levels (LDL), normal hearing thresholds and is sensitive to ordinary environmental sounds. Persons with hyperacusis frequently seek help at audiological departments as they are often affected by other audiological problems. Regrettably, there is neither a consensus-based diagnostic procedure nor an evidence-based treatment for hyperacusis.The principal aim of this thesis was to gain knowledge about the clinical condition hyperacusis. The specific aim of Paper I was to compare hyperacusis measurement tools in order to determine the most valid measures for assessing hyperacusis. Items from a constructed clinical interview were compared with the LDL test, the Hyperacusis Questionnaire (HQ) and the Hospital Anxiety and Depression Scale (HADS). LDLs were significantly correlated with the anxiety subscale of the HADS. A third of the 62 investigated patients scored below the previously recommended cut-off for the HQ. The results suggest that HQ and HADS in combination with a clinical interview are useful as part of the assessment procedure in patients with hyperacusis.The aim of Paper II was to further investigate the patient group with respect to individual characteristics, psychiatric morbidity and personality traits. It was shown that anxiety disorders and anxiety-related personality traits were over-represented, which suggests common or cooperating mechanisms. Avoidance behaviour proved to be very common in the patient group, as was being unable to work due to hyperacusis.In Paper III it was investigated in a randomized controlled trial whether Cognitive Behaviour Therapy (CBT) could be helpful for patients with hyperacusis. The effect of CBT for hyperacusis was assessed with measures of LDLs, symptoms of hyperacusis and of anxiety and depression, fear of (re)injury due to exposure to sounds, and quality of life, compared to a waiting list control group. There were significant group effects for a majority of the measures with moderate and strong effect sizes within- and between groups. After assessment the waiting list group was also given CBT, and was then reassessed with similar effects. The results were maintained for 12 months, concluding CBT to be potentially helpful for these patients.