Conceptualizing the substrates and sequelae of decreased sound tolerance as a developmental cascade: A pilot study.

A growing body of research has shown that decreased sound tolerance (DST) is highly prevalent and impacts the mental health of affected individuals. Recent work has shown this is especially true for autistic individuals. The extant literature has been limited, however, by a focus on DST relatively late in life. Consequently, at present we know little about when and how DST emerges and produces cascading effects on mental health. In this pilot study, we prospectively followed infants at high likelihood for autism, and thus hypothetically for DST, based on their status as younger siblings of autistic children (Sibs-Autism) and infants at lower, general population-level likelihood for these conditions (Sibs-NA) to determine whether (a) DST symptomatology differs based on autism likelihood status and/or diagnostic outcome; (b) indices of early resting brain states, specifically gamma power, predict sensory hyperresponsiveness and DST; (c) sensory hyperresponsiveness predicts DST symptomatology; (d) DST symptomatology predicts anxiety; and (e) if the aforementioned associations vary by familial likelihood for autism or later autism status. Preliminary results indicate that DST symptoms are elevated in Sibs-Autism, particularly those who go on to receive a diagnosis of autism, relative to Sibs-NA. Gamma power is not significantly associated with later sensory hyperresponsiveness or DST, but hyperresponsiveness is associated with later DST, which is associated with later anxiety in Sibs-Autism.