Electrophysiological correlates of early information processing and inhibitory control in adult attention-deficit/hyperactivity disorder
Papp Szilvia
Mental Health Sciences
Dr. Bagdy György
SE Neurológiai és Pszichiátriai Klinika közös tanterme
2025-03-03 09:00:00
Psychiatry
Dr. Réthelyi János
Dr. Czobor Pál
Dr. Bódizs Róbert
Dr. Németh Dezső
Dr. Bereczki Dániel
Dr. Kovács Tibor
Dr. Fodor Kinga
The aim of the two consecutive high-density EEG studies presented in this dissertation was to investigate the electrophysiological characteristics of early information processing and inhibitory control in adult ADHD, both of which have been shown to be deficient in the disorder on the symptomatic level.
In the first study (52) we applied a Go/NoGo task to investigate the P1 event-related potential and found that ADHD patients had a significantly reduced P1 component at occipital and inferotemporal scalp areas compared to controls. Regarding P1 reduction, we found that it correlated with symptoms of inattention and hyperactivity, however in an opposite direction, which is consistent with the idea that symptom presentation in ADHD may be diverse and possibly reflect multiple aetiologies. Our findings therefore indicate that deficits in early sensory processing are present in adult ADHD patients and are associated with symptom severity. These findings are suggestive of bottom-up cognitive deficits in ADHD driven by impairments in early visual processing, and provide evidence that sensory processing problems are present at the neurophysiological level in patients with adult ADHD.
In our second study (76) we investigated the anteriorization of the P3 brain response associated with the NoGo task condition in our adult ADHD patient population and found that patients with ADHD had a significantly diminished P3 NGA response compared to controls. The decrease in NGA was related to important clinical characteristics: patients with higher impulsivity scores had significantly lower NGA, while treatment with stimulant medication, as compared to the lack of such treatment, was associated with a correction of the lower NGA response in ADHD patients. The finding of a diminished NoGo anteriorization in adult ADHD patients is consistent with the inhibitory control and frontal lobe dysfunctions described in the disorder. The inverse relationship between NGA and impulsivity suggests that clinically more severe impulsivity is linked to a more pronounced frontal dysfunction in adult ADHD subjects.
Overall, the findings from the two consecutive studies (52, 76) highlight the importance of focusing on both the bottom-up and top-down deficits in ADHD, which is a multidimensional psychiatric condition with diverse clinical symptom clusters, in order to gain a more comprehensive insight into the potential underlying neurobiological causes of the disorder.
