Feasibility of Functional Near-Infrared Spectroscopy in Assessing Prefrontal Cortical Activation During Behaviour...

Williams syndrome (WS) is a genetic condition associated with neurodevelopmental disorders including intellectual disability and executive functioning (EF) deficits. Although neuroimaging methods may clarify the neural basis of these impairments, participant burden and frequent exclusion of individuals with lower cognitive abilities prevent generalizable studies in WS. Functional near-infrared spectroscopy (fNIRS), a low-burden neuroimaging method, may offer a more accessible way to study the neural correlates of EF in WS. This study examined the feasibility of measuring prefrontal cortex (PFC) activation using fNIRS during a behavioural inhibition task in individuals with WS compared to neural activation and behavioural performance in age-matched typically developing controls.

Thirty-seven individuals with WS and 21 healthy volunteers, aged 3-85, completed resting state and Go/No-Go (GNG) task fNIRS recordings. Feasibility was evaluated through behavioural validity and fNIRS data quality. Prefrontal activation was assessed using oxygenated haemoglobin (HbO) changes during the task. Behavioural performance was measured by commission error rate. One-sample t tests evaluated task-related activation during the 'Go' and 'No-Go' conditions, and Spearman correlations tested associations between activation and behavioural performance.

Eighty-nine percent of individuals with WS completed the resting state portion of the assessment with valid behavioural data, suggesting strong tolerance of the fNIRS platform. Sixty-five percent completed the GNG task without behavioural concerns. Preprocessing was successful in all valid cases, with minimal signal loss. Individuals with WS made significantly more commission errors than healthy volunteers, suggesting impaired behavioural inhibition. fNIRS analyses revealed distinct patterns of PFC activation during inhibition in WS, with significant activation at multiple channels not observed in healthy volunteers. However, activation was not significantly related to behavioural performance across groups.

These results support the feasibility of fNIRS in individuals with WS, including those with varying levels of intellectual disability. The GNG task captured inhibition deficits in WS and elicited differing prefrontal activation, though the rate of behavioural exclusions suggests the task may require adaptation. Overall, fNIRS shows promise as a tolerable and accessible neuroimaging tool in neurodevelopmental populations typically excluded from neuroscientific research.