Behavioral and Neurophysiological Markers of ADHD in Children, Adolescents, and Adults: A Large-Scale Clinical Study

Abstract

This study aimed to re-evaluate the possible differences between attention-deficit/hyperactivity disorder (ADHD) subjects and healthy controls in the context of a standard Go/NoGo task (visual continuous performance test [VCPT]), frequently used to measure executive functions. In contrast to many previous studies, our sample comprises children, adolescents, and adults. We analyzed data from 447 ADHD patients and 227 healthy controls. By applying multivariate linear regression analyses, we controlled the group differences between ADHD patients and controls for age and sex. As dependent variables we used behavioral (number of omission and commission errors, reaction time, and reaction time variability) and neurophysiological measures (event-related potentials [ERPs]). In summary, we successfully replicated the deviations of ADHD subjects from healthy controls. The differences are small to moderate when expressed as effect size measures (number of omission errors: d = 0.60, reaction time variability: d = 0.56, contingent negative variation (CNV) and P3 amplitudes: −0.35 < d < −0.47, ERP latencies: 0.21 < d < 0.29). Further analyses revealed no substantial differences between ADHD subtypes (combined, inattentive, and hyperactive/impulsive presentation), subgroups according to high- and low-symptomatic burden or methylphenidate intake for their daily routine. We successfully replicated known differences between ADHD subjects and controls for the behavioral and neurophysiological variables. However, the small-to-moderate effect sizes limit their utility as biomarkers in the diagnostic procedure. The incongruence of self-reported symptomatic burden and clinical diagnosis emphasizes the challenges of the present clinical diagnosis with low reliability, which partially accounts for the low degree of discrimination between ADHD subjects and controls.

Longitudinal Analysis of Self-Reported Symptoms, Behavioral Measures, and Event-Related Potential Components of a Cued Go/NoGo Task in Adults With Attention-Deficit/Hyperactivity Disorder and Controls

“…This interpretation is supported by the decreasing number of omission errors and faster reaction times with age (Münger et al, 2021). In contrast, during adulthood ERP amplitudes decrease and latencies increase with age (Kropotov et al, 2016;Münger et al, 2021). The later and attenuated peaks are interpreted to reflect a slowing and decline in cognitive processes (Kropotov et al, 2016), which have previously been summarized in the cognitive speed hypothesis of aging (Salthouse, 1996).…”

“…However, it is known that ERP components change throughout the lifetime. Crosssectional analysis suggest that during childhood maturation, ERP amplitudes increase, whereas ERP latencies decrease with age (Münger et al, 2021). This can be interpreted as a gain in function, where cognitive operations become more pronounced and faster with increasing age.…”

“…We addressed the differences in the sex-ratio and age at baseline between groups by including these variables in the structural equation models (for details, see "Statistical Analysis"). The participants described here are part of the total cohort described in a previous publication (Münger et al, 2021).…”

“…This can be interpreted as a gain in function, where cognitive operations become more pronounced and faster with increasing age. This interpretation is supported by the decreasing number of omission errors and faster reaction times with age (Münger et al, 2021). In contrast, during adulthood ERP amplitudes decrease and latencies increase with age (Kropotov et al, 2016;Münger et al, 2021).…”

“…A recent meta-analysis revealed attenuated amplitudes and increased latencies in several components (Kaiser et al, 2020). Most of these studies focus on components that address inhibition of action, sustained attention and conflict detection, and show that ADHD subjects moderately differ from healthy controls (Münger et al, 2021).…”