Decreased sound toleranceas a transdiagnostic feature of neurodiversity with loudness hyperacusisas a central player

Decreased sound tolerance (DST) is an important source of impairment for autistic individuals and a research priority for stakeholders. While various sensory symptoms are associated with autism spectrum conditions (ASC) and linearly correlated with autistic traits (ATs), the relative roles of the DST subtypes, hyperacusis, misophonia, and phonophobia, are unknown. We collected psychometric data on loudness hyperacusis, misophonia and phonophobia symptoms from 336 adults (32.4% with ASC) with a broad distribution of ATs, to allow analysis of the association of DST subtypes with both ASC and ATs. We found that symptoms associated with all three DST constructs were elevated in ASC and correlated with higher ATs. However, the presence and severity of misophonia and phonophobia were to a great extent contingent on the presence of loudness hyperacusis. Misophonic triggers related to ASC and ATs were muffled sounds and background talk, rather than the oronasal triggers classically associated with misophonia, such as eating sounds. Limitations include a reliance on self-reported normal peripheral hearing and neurodevelopmental conditions, but strengths include the large sample and highly reliable measures. We conclude that loudness hyperacusis is the dominant DST pattern associated with ASC and ATs.