Auditory Distraction in ADHD : From Behaviour to the Brain

Abstract: ADHD is a heterogenous disorder encompassing neurodevelopmental deficits in cognitive control. Auditory distraction is a common clinically reported symptom in ADHD, yet empirical research investigating the manifestation of auditory distraction in the disorder is remarkably scarce. Findings from cognitive hearing science highlight the crucial role cognitive control plays in an individual’s ability to gate, attenuate and/or compensate for auditory distraction. However the field is yet to extensively test hypotheses in normal hearing populations with neurodevelopmental deficits in cognitive control such as ADHD. This thesis contributes to narrowing the gap within these two fields of research by studying auditory distraction in this clinical population to a greater extent than previous reports in the literature.Using a combination of both behavioural and neuroimaging methods, the research presented here was able to show that adults and adolescents with ADHD are inherently more susceptible to auditory distraction than their non-ADHD counterparts. At the behavioural level, impaired task performance due to auditory distraction was more likely to manifest in ADHD participants when the working memory system was under high processing load. At the neural level, functional aberrancy in auditory attention was evident at early stages of sensory processing in a variety of tasks, implicating both exogenous and endogenous control systems in ADHD. Furthermore, the distribution of ADHD-symptom severity across participants was shown to correlate with increases in both cortical activity to auditory distractors and intrinsic functional connectivity between auditory and exogenous attention networks.In line with evidence from cognitive hearing science, the general findings of this thesis demonstrate that cognitive control plays an important role in the ability to perceive sound under suboptimal listening conditions and hamper distraction. In addition, findings challenge theories of ADHD that question the extent in which sensory-related attentional control is impaired. More empirical research on the auditory modality in ADHD is therefore encouraged in order to revise models, improve diagnostic tools, and develop evidence-based interventions targeting study/work environments.