Sources of cortical rhythms change as a function of cognitive impairment in pathological aging: a multicenter study.
OBJECTIVE
The present study tested the hypothesis that cortical electroencephalographic (EEG) rhythms. change across normal elderly (Nold), mild cognitive impairment (MCI), and Alzheimer's disease (AD) subjects as a function of the global cognitive level.


METHODS
Resting eyes-closed EEG data were recorded in 155 MCI, 193 mild AD, and 126 age-matched Nold subjects. EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). EEG cortical sources were estimated by LORETA.


RESULTS
Occipital delta and alpha 1 sources in parietal, occipital, temporal, and 'limbic' areas had an intermediate magnitude in MCI subjects compared to mild AD and Nold subjects. These five EEG sources presented both linear and nonlinear (linear, exponential, logarithmic, and power) correlations with the global cognitive level (as revealed by mini mental state examination score) across all subjects.


CONCLUSIONS
Cortical EEG rhythms change in pathological aging as a function of the global cognitive level.


CONCLUSIONS
The present functional data on large populations support the 'transitional hypothesis' of a shadow zone across normality, pre-clinical stage of dementia (MCI), and AD.
Babiloni
Claudio
C
Dip. Fisiologia Umana e Farmacologia, Univ. La Sapienza Rome, Italy. claudio.babiloni@uniroma1.it
Binetti
Giuliano
G
Cassetta
Emanuele
E
Dal Forno
Gloria
G
Del Percio
Claudio
C
Ferreri
Florinda
F
Ferri
Raffaele
R
Frisoni
Giovanni
G
Hirata
Koichi
K
Lanuzza
Bartolo
B
Miniussi
Carlo
C
Moretti
Davide V
DV
Nobili
Flavio
F
Rodriguez
Guido
G
Romani
Gian Luca
GL
Salinari
Serenella
S
Rossini
Paolo M
PM
D000368:Aged; D000375:Aging / Q000473:pathology*; D000544:Alzheimer Disease / Q000503:physiopathology; D001931:Brain Mapping; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000503:physiopathology*; D003072:Cognition Disorders / Q000503:physiopathology*; D004569:Electroencephalography / Q000145:classification / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008609:Mental Status Schedule / Q000706:statistics & numerical data; D008875:Middle Aged; D012189:Retrospective Studies; D012815:Signal Processing, Computer-Assisted; D013057:Spectrum Analysis; D013223:Statistics as Topic