Estimating causal effects of neurodevelopmental hyperacusis on anxiety and quality of life

Many children with normal peripheral hearing perceive everyday sounds louder than their peers do. Such Neurodevelopmental Hyperacusis (HAND) is often part of sensory over-responsivity associated with neuropsychiatric differences. To better understand the impact of HAND on individuals’ lives, this study aimed to estimate the magnitude of the effect of HAND on quality of life (QoL) using causal inference. Given previously established relationships between sensory sensitivity and anxiety, we also aimed to estimate the role of anxiety as a mediator of this effect. We recruited 174 legal guardians of children (8–11 years old), and collected informant-rated scores for QoL, HAND, and anxiety, as well as data on confounders identified using a causal graph. There was a large total negative effect of HAND on QoL, with a significant proportion mediated through anxiety. Post-hoc analyses indicated that almost all domains of QoL were negatively affected by HAND, with especially large effect sizes for psychological, emotional and social domains. We discuss the results in the light of our causal assumptions and conclude that 1) intervention for HAND would likely improve both QoL and anxiety in affected individuals, and 2) anxiety treatment would achieve some, but not all, of this beneficial effect on QoL.