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EEG evidence for a new conceptualisation of attention deficit hyperactivity disorder
Adam R Clarke1, Robert J Barry, Rory McCarthy
1Brain and Behaviour Research Institute, University of Wollongong, Australia. adam_clarke@uow.edu.au
Insights
Researchers identified two distinct electroencephalographic (EEG) clusters in children with attention-deficit/hyperactivity disorder (ADHD), suggesting subtypes based on brain activity rather than behavior.
Area of Science:
- Neuroscience
- Child Psychology
- Biomedical Engineering
Background:
- Attention-deficit/hyperactivity disorder (ADHD) is a prevalent neurodevelopmental disorder.
- The inattentive subtype of ADHD presents unique diagnostic challenges.
- Current diagnostic criteria for ADHD may not fully capture underlying neurobiological heterogeneity.
Purpose of the Study:
- To investigate electroencephalographic (EEG) patterns in children with the inattentive subtype of ADHD.
- To identify distinct EEG clusters within this population.
- To explore potential neurobiological subtypes of ADHD.
Main Methods:
- Utilized electroencephalography (EEG) in 100 boys with ADHD and 40 controls.
- Recorded EEG during a resting, eyes-closed condition.
- Applied Fourier transformation, factor analysis, and cluster analysis to EEG data.
Main Results:
- Identified two distinct EEG clusters in children with inattentive ADHD.
- Cluster 1: Increased high-amplitude theta with reduced delta and beta activity.
- Cluster 2: Increased slow wave activity with reduced fast wave activity.
Conclusions:
- The identified EEG clusters suggest distinct neurobiological subtypes of ADHD.
- These subtypes may represent cortical hypoarousal and central nervous system (CNS) maturational lag.
- Findings support a re-conceptualization of ADHD based on CNS abnormalities for improved predictive validity.
Objectives:
This study investigated the presence of electroencephalographic (EEG) clusters within a sample of children with the inattentive type of attention-deficit/hyperactivity disorder (ADHD).
Methods:
Subjects consisted of 100 boys with ADHD and 40 age-matched controls. EEG was recorded from 21 sites during an eyes-closed resting condition and Fourier transformed to provide estimates for total power, and relative power in the delta, theta, alpha and beta bands. Factor analysis was used to group sites into 3 regions; frontal, central and posterior. These data were subjected to cluster analysis.
Results:
Two distinct EEG clusters of children with the inattentive type of ADHD were found. These were characterised by (a) increased high-amplitude theta with deficiencies of delta and beta activities, and (b) increased slow wave and deficiencies of fast wave activity.
Conclusions:
These two subtypes are independent of current diagnostic categories, and consist of a cortically hypoaroused group and a group typified by a maturational lag in central nervous system (CNS) development. These results support a re-conceptualisation of ADHD based on the CNS abnormality underlying the disorder rather than the behavioural profile of the child. This has the potential to add a level of predictive validity, which is currently lacking in the present diagnostic systems.