Abstract
INTRODUCTION: Theta-to-beta ratio (TBR) has been claimed as a biomarker to diagnose attention-deficit/hyperactivity disorder (ADHD). However, the effectiveness of this index in identifying different groups of ADHD is still under discussion. Our primary purpose was to determine to what extent active TBR can differentiate between children with ADHD and specific learning disorder (SLD) as the most common comorbid disorder. METHODS: Two groups of school-aged children with SLD (n=15) and ADHD (n=15) were diagnosed through a process of clinical interview and observation. Electroencephalography (EEG) was recorded in both groups during active conditions. The implemented cognitive task was the visual continuous performance task (VCPT). TBR in sites of CZ and Fz and cognitive measures of VCPT were calculated in the study groups. RESULTS: There were no significant differences in cognitive measures (commission, omission, reaction time, and variability of reaction times) shown in two matched groups of children with SLD and ADHD. According to TBR, the two groups demonstrated no significant differences in comparison. CONCLUSION: TBR cannot be considered a reliable biomarker to differentiate between those groups of psychological disorders that contain primary cognitive deficits and require the allocation of attention and working memory loads.