Resting-state EEG gamma activity in children with attention-deficit/hyperactivity disorder
Robert J Barry1, Adam R Clarke, Mihaly Hajos
1Brain & Behaviour Research Institute and School of Psychology, University of Wollongong, Wollongong 2522, Australia. Robert_Barry@uow.edu.au
Insights
Children with Attention-Deficit/Hyperactivity Disorder (AD/HD) exhibit reduced gamma band activity in resting-state EEG, correlating with inattention. This finding extends known EEG differences and highlights potential cognitive processing issues.
Area of Science:
- Neuroscience
- Pediatrics
- Psychiatry
Background:
- Attention-Deficit/Hyperactivity Disorder (AD/HD) is associated with known electroencephalogram (EEG) abnormalities in delta, theta, alpha, and beta bands.
- The role of the gamma band in AD/HD has been less explored.
Purpose of the Study:
- To investigate resting-state EEG, with a specific focus on gamma activity, in children diagnosed with AD/HD.
- To compare EEG findings, including gamma band power, between children with AD/HD and matched controls.
Main Methods:
- Resting-state EEG was recorded from 40 children with AD/HD and 40 age- and sex-matched controls using 19 scalp sites.
- EEG data were analyzed for absolute and relative power in delta, theta, alpha, beta, and gamma frequency bands.
Main Results:
- Children with AD/HD showed higher absolute delta and theta power, and lower absolute beta and gamma power compared to controls.
- Relative power measures indicated enhanced delta and theta activity, with reduced alpha, beta, and gamma activity in the AD/HD group.
- Absolute gamma power was negatively correlated with inattention scores.
Conclusions:
- The study confirms typical EEG profiles in AD/HD across delta, theta, alpha, and beta bands.
- Children with AD/HD exhibit reduced absolute and relative gamma activity during eyes-closed rest.
- These gamma band differences are significant for understanding stimulus processing and behavioral outcomes in AD/HD, particularly in relation to inattention.
Objective:
Children with Attention-Deficit/Hyperactivity Disorder (AD/HD) have well-described abnormalities in the four traditional EEG bands. However, to date the gamma band has not been widely investigated. This study investigated resting-state EEG in children with AD/HD and matched controls, with a particular focus on gamma activity.
Method:
Forty children with AD/HD, and 40 age- and sex-matched controls, participated. EEG was recorded from 19 sites during an eyes-closed resting condition and Fourier transformed to provide estimates for absolute and relative power in the delta, theta, alpha, beta and gamma bands.
Results:
Children with AD/HD had elevated levels of absolute delta and theta power, and decreased levels of absolute beta and gamma power, compared to controls. With relative power measures, children with AD/HD showed enhanced delta and theta activity, with reduced alpha, beta and gamma activity. Inattention scores on the Conners' Parent Rating Scale were negatively correlated with absolute gamma.
Conclusions:
These patients demonstrate the typical EEG profile in the eyes-closed resting state, over the delta, theta, alpha and beta bands, associated with AD/HD. In addition, compared with controls, they demonstrate reduced absolute and relative gamma activity. These differences appear to contribute importantly to their dysfunctional stimulus processing, and impact their behavioural outcomes.
Significance:
This resting-state study extends the well-established fast-wave EEG deficits in children with AD/HD to the gamma band, and links that to increased inattention, which is of special importance in understanding their cognitive-processing problems.
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