A Retrospective Study Distinguishing between Hyperacusis and Misophonia in children with Auditory Processing Disorder (APD).

Objectives: Decreased sound tolerance (DST) is common in children with auditory processing disorder (APD). This study aimed to differentiate between hyperacusis and misophonia in children with APD.

Design: A retrospective study evaluating outcomes of structured history and co-morbidity following Research Domain Criteria (RDoC) frame-work. Misophonia was considered as oversensitivity to eating/chewing sounds and hyperacusis as oversensitivity to other sounds.

Study Sample: Two hundred and seventy-nine children (160 males; 119 females), 6-16 year-olds with NVIQ ≥80, diagnosed with APD between January 2021 and December 2022.

Results: One hundred and forty-three out of 279 children with APD had DST, of which 107 had hyperacusis (without misophonia) and 36 had misophonia. Misophonia co-existed with hyperacusis in 35 children (97 %), and in one child misophonia occurred without hyperacusis. Misophonia was prevalent in older children, in females, and those with tinnitus. Fear and being upset were predominant emotional responses in hyperacusis (without misophonia) while disgust and verbal abuse were prevalent in misophonia (with or without hyperacusis). Compared to children without DST, the hyperacusis (without misophonia) and misophonia (with or without hyperacusis) groups had significant higher prevalence of ADHD, anxiety, and language impairment. Educational difficulties were similar in APD irrespective of the presence or absence of DST. Despite higher tinnitus prevalence in misophonia (with or without hyperacusis) along with similar co-morbidities and educational difficulties in both hyperacusis (without misophonia) and misophonia (with or without hyperacusis), the misophonia (with or without hyperacusis) group surprisingly had less support at school which was reflected in fewer Education, Health and Care Plan (EHCP).

Conclusions: In APD misophonia mostly co-exists with hyperacusis, with differences in emotional responses, tinnitus prevalence, and gender distribution when compared to hyperacusis (without misophonia). Increase in awareness about misophonia is needed, as children with misophonia may have unidentified needs. Larger scale prospective study is required to clarify if misophonia evolves from hyperacusis, and to explore the factors underlying 'misophonia with hyperacusis' and 'misophonia without hyperacusis'. For clarity, DST studies need to specify if hyperacusis or misophonia co-existed when referring to hyperacusis or misophonia.