A study of dynamic functional brain connectivity in the comorbidity of autism spectrum disorder and attention-deficit/hyperactivity disorder

ObjectiveThis study aimed to examine the differences in dynamic brain functional connectivity between individuals with comorbid autism spectrum disorder and attention-deficit/hyperactivity disorder (ASD+ADHD) and those with ASD only (ASD-only).MethodsThe study included 40 ASD+ADHD, 74 ASD-only, and 161 typically developing (TD) individuals and their resting-state functional magnetic resonance imaging data were obtained from the Autism Brain Imaging Data Exchange II (ABIDE-2). The dynamic functional connectivity analyses were conducted to identify dynamic functional connectivity states. The temporal attributes of these states were extracted for between-group comparisons.ResultsClustering analysis identified the following three repeated and highly structured functional connectivity states. State 1 represented a strongly connected state, characterised by predominantly high-intensity functional connectivity, occurring infrequently (6.16%). State 2 was the locally connected state, characterized by high-strength positive functional connectivity within local regions, with most other connections weakly connected. This state had the highest frequency (51.31%). State 3 was the extensively connected state with a relatively wide distribution of high-intensity positive functional connectivity. Occurring at a frequency of 42.63%. There were significant differences among the three groups in mean dwell time of State 3 (P=0.006) and the number of state transitions (PPPr=0.355, P=0.054).ConclusionCompared with the ASD-only and TD groups, the ASD+ADHD group exhibit a preference for remaining in the extensively connected state and made fewer transitions among states. The individuals with ASD+ADHD exhibited insufficient flexibility in brain functional activities, which may represent a potential neurophysiological characteristic of ASD+ADHD.