Global dimensional complexity of multichannel EEG in mild Alzheimer's disease and age-matched cohorts.
Multichannel EEG as sequence of momentary brain field maps constitutes a trajectory through K-dimensional state space (K = number of channels); the complexity of this trajectory is assessed by the nonlinear measure of global correlation dimension (Global Dimensional Complexity, GDC) with the number of electrodes as embedding dimension. We analyzed eyes-closed EEG of three age-matched subject groups: mild Alzheimer's disease (AD; n = 21), mild cognitive impairment (29) and subjective memory complaint (29). Kruskal-Wallis statistics showed an overall effect between groups. AD patients differed significantly (GDC = 4.56) from mild cognitive impairments (GDC = 4.98) and from subjective memory complaints (GDC = 4.93). GDC also had significant positive correlations with mental condition and performance (MMSE and WAIS-R scores). Thus, the dynamics of brain state development over time in mild AD differs from that in mild cognitive impairment and in subjective memory complaint cases.
Yagyu
T
T
KEY Institute for Brain-Mind Research, University Hospital of Psychiatry, Zürich, Switzerland.
Wackermann
J
J
Shigeta
M
M
Jelic
V
V
Kinoshita
T
T
Kochi
K
K
Julin
P
P
Almkvist
O
O
Wahlund
L O
LO
Kondakor
I
I
Lehmann
D
D
D000368:Aged; D000544:Alzheimer Disease / Q000150:complications / Q000175:diagnosis*; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology; D015331:Cohort Studies; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D011446:Prospective Studies; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric