title: Effects of age upon interhemispheric EEG coherence in normal adults.
abstract: Age-related differences in quantified electrophysiological measures of interhemispheric EEG coherence were studied in 371 subjects (171 males and 200 females), ages 20-80, all of whom were judged to be optimally healthy. Principal components analysis (PCA) was performed on interhemispheric coherence of Laplacian referenced data from eight homologous left-right electrode pairs, from 0.5 to 32 Hz. Regression procedures, using signals from artifact monitoring channels, were used to minimize effects of eye movement and muscle artifact. Forty-six factors described 80% of the total variance, with electrode location the primary source of communality in factor formation. Within 350 right-handed subjects, results indicated a broad trend for decreased interhemispheric coherence with advancing age. Using canonical correlation, the coherence-based factors also successfully predicted spectral variables, previously found to maximally illustrate age-related EEG desynchronization. We speculate that age-related reduction of interhemispheric coherence may in part explain age-related EEG desynchrony and stems from age-related reduction of cortical connectivity. Gender differences of interhemispheric coherence were also evident. Females demonstrated higher interhemispheric coherence than males. Within a smaller subpopulation of 63 subjects (21 left and 42 right handed), there was a gender-by-handedness interaction, with higher interhemispheric coherence in right-handed females than right-handed males and the reverse in left-handed male and female subjects.
authors.affiliation: Department of Neurology, Children's Hospital, Boston 02115, MA, USA.
authors.forename: F H
authors.initials: FH
authors.lastname: Duffy
authors.forename: G B
authors.initials: GB
authors.lastname: Mcanulty
authors.forename: M S
authors.initials: MS
authors.lastname: Albert
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D001921:Brain / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012737:Sex Factors