Examining resting-state EEG features and comparing non-pharmacologic interventions among children with AD/HD

Attention-deficit/hyperactivity disorder (AD/HD) is a common neurodevelopmental disorder with early childhood onset and long-lasting symptoms. The resting-state electroencephalogram (RS-EEG), which directly measures central nervous system activity, is considered as a potential tool to diagnose AD/HD. However, its diagnostic value is recently in debate. The first aim of this thesis was to explore if the theta-to-beta ratio (TBR) can distinguish AD/HD from controls (Study 1) and examine a methodological consideration that may influence the group comparison (Study 2). Moreover, a prognostic perspective of using RS-EEG in AD/HD was provided in recent studies. Based on the evidence that resting brain activity contributes to individual task-related performance, study 1 also preliminarily explored the relationship between RS-EEG and executive functions (EF), to examine if RS-EEG can be in a prognostic manner to predict EF performance. Following this perspective, two subsequent studies were conducted to extend the preliminary findings: Study 3 examined the association between TBR and inhibitory functions, and Study 4 used RS-EEG measures from different resting states as a whole to explore the role of RS-EEG measures in common EF and day-to-day EF. The third aim was encouraged by the need of non-pharmacological inventions in children with AD/HD. As RS-EEG and EF based inventions show promising results, Study 5 preliminarily compared three invention protocols (cognitive training, neurofeedback training, and combined training) in terms of transfer effects. Overall, this thesis found that RS-EEG measures derived from spectral power analysis such as TBR may not reliably diagnose children with AD/HD. Rather, RS-EEG measures are related to different types of EFs, which suggests that RS-EEG may be served as prognostic indicators to predict EF performance. Together, these results contribute to the discussion about the clinical value of RS-EEG in children with AD/HD. Also, the results lead to methodological considerations of detecting AD/HD versus control differences and the suggestion for future AD/HD models. In addition, as the preliminary intervention study showed the narrow transfer effects of cognitive and neurofeedback training, this thesis supports that these nonpharmacological interventions may be served as an adjunct treatment; meanwhile, some suggestions are offered to optimise training protocols.