Response inhibition and working memory in children with attention deficit hyperactivity disorders: An event-related potential study

BACKGROUND: To assess the combined N-back/Nogo paradigm applicability in the measurement of cognitive functions of response inhibition and working memory and to further determine the mechanisms underlying the occurrence of response inhibition and working memory deficits in children with ADHD. MATERIAL AND METHODS: This study used a two-phase design. In Experiment 1, 30 healthy children were recruited via convenience sampling. They performed single N-back, single Go/Nogo, and combined N-back/Nogo tasks while ERPs and behavioral data were recorded. In Experiment 2, 41 children with ADHD were screened using a convenience whole-group sampling method, and 34 healthy controls were matched by sex and age. Both groups completed the combined N-back/Nogo task while ERPs and behavioral performance were assessed. RESULTS: Experiment 1: Comparisons between single and combined tasks in healthy children. There was no significant difference between the single and combined N-back/Nogo tasks on measures of accuracy rate, omission rate, or ERPs (all P > 0.05). Experiment 2: Compared the ADHD and healthy control groups using the combined N-back/Nogo task. The ADHD group demonstrated significantly lower accuracy on both N-back and Nogo components, alongside a higher omission rate specifically on the Nogo component (P < 0.05). The ERP results further revealed reductions in the N-back P300 peak amplitude at sites F4, C3, Cz, C4, and P3 in the ADHD group. Additionally, the ADHD group exhibited prolonged latency of the Nogo-N200 peak at the F3 and C4 sites (all P < 0.05). CONCLUSION: The study revealed working memory and response inhibition deficits in children with ADHD from Xinjiang, using a combined N-back/Nogo paradigm. This also demonstrates the paradigm's applicability in measuring these cognitive functions.