Audiovisual Decision-Making and Sensory Evidence Weighting in Young Adults with ADHD-like Traits

Multisensory integration (MSI) allows the brain to combine information from different sensory modalities to form a coherent perception of the environment. Externalizing disorders with impulsivity as a key symptom such as Attention-Deficit/Hyperactivity Disorder (ADHD) have been associated with altered sensory processing and decision-making. This study investigated the relationship between impulsivity and impulsivity related behaviours, and multisensory integration. Participants had to discriminate between two visual gratings, and/or two sounds presented to the right and left ear based on respectively contrast and loudness in a two-alternative forced-choice task. The study included 44 participants, 13 of whom were diagnosed with ADHD or Disruptive Behaviour Disorders. Results show similar task performance across participants. Performance accuracies were highest on audiovisual trials and participants responded fastest on auditory trials, independent of impulsivity levels. Examining the timescale of evidence weighting revealed that early sensory information contributed most to decisions, with dynamic dominance switching between visual and auditory modalities. We found no evidence that the temporal dynamics were affected by impulsivity. These findings suggest that impulsivity and impulsivity related behaviours do not significantly affect MSI during our task and that sensory processing mechanisms remain robust against individual impulsivity levels.