Background
An elevated excitation/inhibition ratio has been suggested as one mechanism underpinning
autism. An imbalance between cortical excitation and inhibition may manifest itself
in electroencephalogram (EEG) abnormalities in the high frequency range. The aim of
this study was to investigate whether beta and gamma range EEG abnormalities are characteristic
for young boys with autism (BWA).
Methods
EEG was recorded during sustained visual attention in two independent samples of BWA
from Moscow and Gothenburg, aged 3 to 8 years, and in age matched typically developing
boys (TDB). High frequency EEG spectral power was analyzed.
Results
In both samples, BWA demonstrated a pathological increase of gamma (24.4–44.0 Hz)
activity at the electrode locations distant from the sources of myogenic artefacts.
In both samples, the amount of gamma activity correlated positively with degree of
developmental delay in BWA.
Conclusions
The excess of high frequency oscillations may reflect imbalance in the excitation–inhibition
homeostasis in the cortex. Given the important role of high frequency EEG rhythms
for perceptual and cognitive processes, early and probably genetically determined
abnormalities in the neuronal mechanisms generating high frequency EEG rhythms may
contribute to development of the disorder. Further studies are needed to investigate
the specificity of the findings for autism.
Key Words
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Article info
Publication history
Published online: June 02, 2007
Accepted:
December 20,
2006
Received in revised form:
December 5,
2006
Received:
October 3,
2006
Identification
Copyright
© 2007 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.
