EEG spectra in dyslexic and control boys during resting conditions.
We studied the resting eyes open and eyes closed EEG in carefully screened samples of 9-13-year-old dyslexic and control boys within a 2-cohort cross-validation design with repeat testing 1-3 years later. We found: no difference between groups in delta or theta activity in either cohort or in repeat testing 1-3 years later; in the dyslexics, decreased beta (19-24 c/sec) activity at bilateral central, parietal and mid-temporal leads referenced to vertex; inconsistent group differences in the alpha band: the first cohort dyslexics had lower alpha power than did the controls, but there was no group difference in the second cohort; and significant relative delta differences between groups in the first cohort, which were shown to be a statistical artifact of the use of relative power. We conclude that: dyslexia per se is not associated with increased absolute power in the delta and theta bands; lower power in the high beta band is reliably found in these samples of dyslexics without other disorders; and alpha power levels are not consistently lower in the dyslexic group.
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Fein
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Galin
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Yingling
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Johnstone
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Davenport
J
J
Herron
D000513:Alpha Rhythm; D001611:Beta Rhythm; D002648:Child; D003700:Delta Rhythm; D004410:Dyslexia / Q000503:physiopathology*; D004569:Electroencephalography; D006801:Humans; D008297:Male; D012016:Reference Values; D012146:Rest; D013826:Theta Rhythm