Electroencephalogram valid rate in simple reaction time task as an easy index of children's attention functions

Background Electroencephalogram (EEG) signal artifacts occur often in children, but an EEG valid rate (VR), constructed by excluding the artifacts, might be meaningful to evaluate children's neuropsychological functions. The aim of this study was to develop an easy screening index, the EEGVR, and to investigate attention function in children using this index. Methods The EEG was carried out during a 4 min simple reaction time (SRT) task as standard procedure in 50 children, consisting of 26 with attention-deficit-hyperactivity disorder (ADHD; mean age, 9.8 years; range, 8-11.3 years) and 24 without (mean age, 10.1 years; range, 7.8-12 years). An easy index was derived from the valid rate (VR) of EEG using area under the receiver operating characteristic curve. The index was applied to regroup the 50 children into high VR (HVR) and low VR (LVR) groups, while the Comprehensive Non-verbal Attention Test (CNAT) and four behavioral questionnaires were compared between the two groups in order to investigate the validity of this index. Results The EEGVR at 75% was optimal to identify HVR and LVR (sensitivity, 0.769; specificity, 0.792). The LVR group had significantly lower scores on both CNAT and the behavioral questionnaires, although the demographic variables and full-scale intelligence quotient (FSIQ) were similar between the two groups. Conclusions The EEGVR in an SRT task might be an easy and effective index to screen the attention function of children, and could consequently contribute to the early diagnosis of ADHD.