Atypical Electrophysiological Indices of Eyes-Open and Eyes-Closed Resting-State in Children and Adolescents with ADHD and Autism.

Alessio Bellato,Madeleine J Groom,Chris Hollis,Iti Arora,Puja Kochhar

doi:10.3390/brainsci10050272

Abstract

Investigating electrophysiological measures during resting-state might be useful to investigate brain functioning and responsivity in individuals under diagnostic assessment for attention deficit hyperactivity disorder (ADHD) and autism. EEG was recorded in 43 children with or without ADHD and autism, during a 4-min-long resting-state session which included an eyes-closed and an eyes-open condition. We calculated and analyzed occipital absolute and relative spectral power in the alpha frequency band (8–12 Hz), and alpha reactivity, conceptualized as the difference in alpha power between eyes-closed and eyes-open conditions. Alpha power was increased during eyes-closed compared to eyes-open resting-state. While absolute alpha power was reduced in children with autism, relative alpha power was reduced in children with ADHD, especially during the eyes-closed condition. Reduced relative alpha reactivity was mainly associated with lower IQ and not with ADHD or autism. Atypical brain functioning during resting-state seems differently associated with ADHD and autism, however further studies replicating these results are needed; we therefore suggest involving research groups worldwide by creating a shared and publicly available repository of resting-state EEG data collected in people with different psychological, psychiatric, or neurodevelopmental conditions, including ADHD and autism.

Highlights

Attention deficit hyperactivity disorder (ADHD) affects about 5% of children worldwide, and it is characterized by symptoms of inattention and hyperactivity/impulsivity, which are associated with difficulties in regulating behavior and reduced adaptive functioning [1]
Separate repeated measures Bayesian ANCOVAs were carried out on absolute and relative alpha spectral power measured at the central-occipital scalp region, which were compared across the two Conditions and in relation to attention deficit hyperactivity disorder (ADHD)- and autism-diagnoses, controlling for gender and IQ
Our results provided anecdotal evidence of the presence of a main effect of autism (BFinclusion = 2.530), indicating that children with autism had reduced absolute alpha power, compared to children without autism (ADHD-only and typically developing controls) (BFcorrected = 3.896; Figure 2)

Summary

Introduction

Attention deficit hyperactivity disorder (ADHD) affects about 5% of children worldwide, and it is characterized by symptoms of inattention and hyperactivity/impulsivity, which are associated with difficulties in regulating behavior and reduced adaptive functioning [1]. Despite researchers’ efforts that have resulted in numerous published studies which highlighted atypical brain functioning in ADHD, the difficulty in translating important research findings into clinical practice, added to the widely recognized “replicability crisis” in psychiatry, psychology, and neuroscience [4], have indirectly highlighted the need to identify specific domains which are more likely to be associated with sets of clinical symptoms (both condition-specific and transdiagnostic). It has been widely demonstrated that resting-state EEG is predominantly characterized by oscillatory activity in the alpha frequency band (8–12 Hz), especially over occipital scalp regions and more markedly at rest with eyes closed [7]. Alpha oscillations have been proposed to reflect a general physiological property of neuronal cells and brain systems, and to be involved in different cognitive functions [8] and to be associated with functioning of autonomic and vegetative arousal systems [9]

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