Association between changes in EEG alpha power and behavioural outcome in autistic children induced by child‐centred play therapy: A randomised controlled trial

Abstract Objective The traditional research on evaluating psychological interventions has primarily relied on behavioural measurements (e.g. self‐report questionnaires). This study aimed to investigate the effects of child‐centred play therapy (CCPT) on autistic children at both behavioural and neural levels, as well as the association between the changes in neural and behavioural measurements induced by CCPT. It is hypothesised that alpha power would increase after CCPT, along with improvements in social responsiveness, adaptive social behaviour and autism spectrum disorder (ASD) social symptom measures and that these changes would be correlated across participants. Method A total of 65 autistic children were randomly assigned to a CCPT experimental group ( n = 34; M age = 7.50) or a waitlist control group ( n = 31; M age = 7.47). Electroencephalography (EEG) alpha power and behavioural data were recorded during pre‐ and post‐intervention assessment sessions. The behavioural measurements included the Social Responsiveness Scale‐2, Autism Spectrum Quotient—Child (social skill subscale) and Adaptive Behaviour Assessment System‐II (social domain). t ‐Tests and correlational analyses were conducted to examine the CCPT effects and brain–behaviour associations. Results The results confirmed the effects of CCPT at both neural and behavioural levels and the association between these two levels across participants. Specifically, individuals with larger increases in alpha power after CCPT also showed greater behavioural improvement. Conclusion This study marks an initial endeavour, providing the first cross‐validation of CCPT effects on autistic children by demonstrating the brain–behaviour association. This approach advances the understanding of the therapeutic intervention effects of CCPT by presenting its multilevel impacts.