中華心理衛生協會

Purpose: The existing literature using electroencephalographic (EEG) measures (i.e., theta/beta ratios, resting-state absolute power, and event-related potentials) has supported the benefits of stimulant medication in the treatment of attention-deficit/hyperactivity disorder (ADHD). However, event-related oscillations (EROs), which provide advantages in capturing cognitive processing through time-frequency decomposition, remain underexplored as a tool in this domain. We investigated the differences in brain activity between medicated and unmedicated children with ADHD using EROs and EEG coherence analysis as a measure of functional brain connectivity. Methods: We recruited 54 children aged 6 to 12 years who had been diagnosed with ADHD by child psychiatrists. We divided them into 2 groups based on their treatment status: a medicated group (21 children, mean age = 8.81, male-to-female ratio = 17:4) and an unmedicated group (33 children, mean age = 8.18, male-to-female ratio = 28:5). Each participant underwent an electroencephalography (EEG) device recording with assistance from researchers and participated in 2 phases of the study: a 3-minute eyes-open resting state (EO-RS), and a cognitive task. We analyzed their demographic and clinical characteristics using chi-square tests for categorical variables and an ANOVA for continuous variables. We analyzed the EEG data using the Mann-Whitney U test. Results: During the EO-RS, the medicated group exhibited significantly lower power across the slow-wave frequency bands (Delta, Theta, and Alpha) than the unmedicated group. During the cognitive task, the medicated group showed significantly greater coherence in slow-wave bands between the frontal and parietal regions than the unmedicated group. Conclusion: These results indicate that unmedicated children with ADHD tend to let their minds wander, as reflected by the increased low-frequency power. In contrast, medicated children demonstrated stronger brain connectivity during EO-RS and cognitive tasks. In other words, stimulant medication appears to enhance brain readiness for learning and improve attention control in school-aged children with ADHD. These findings suggest that continuous monitoring of dynamic cognitive states and associated brain activity, indexed by EROs and coherence analyses, may serve as an ecologically valid and effective method for evaluating the treatment process.