Cochlear Non-linearity and Efferent System Functioning in Individuals with Misophonia

Abstract

Misophonia is a condition characterized by abnormally heightened sensitivity towards specific sound stimuli called triggers causing strong emotional and physiological reactions that can escalate to anger. The study aimed at understanding the cochlear (linear and non-linear) and auditory efferent system functioning in misophonics. 30 individuals each with misophonia and individuals without misophonia were included in the study. Transient evoked otoacoustic emission (TEOAE) and distortion product otoacoustic emission input-output (DPOAE I/O) function was obtained. TEOAEs were obtained in conditions with and without contralateral noise to assess the auditory efferent system. Results showed no statistically significant difference (> 0.05) in the global amplitude of TEOAEs, suppression amplitude of TEOAEs and the slopes of the DPOAE I/O function between individuals with misophonia and without misophonia. Individuals with misophonia showed a statistically greater (<0.05) waveform shift upon contralateral noise presentation indicating hyperfunctioning of the auditory efferent system. Results suggest that the cochlear mechanisms are normally functional in individuals with misophonia whereas the auditory efferent system hyperactivity may indicate pathophysiological underpinnings in them, which needs to be further investigated. The findings of the study have clinical implications in terms of refining diagnostic criteria, developing targeted interventions, and enhancing our understanding of the mechanisms underlying misophonia.