Fronto-parietal coupling of brain rhythms in mild cognitive impairment: a multicentric EEG study.
Electroencephalographic (EEG) data were recorded in 69 normal elderly (Nold), 88 mild cognitive impairment (MCI), and 109 mild Alzheimer's disease (AD) subjects at rest condition, to test whether the fronto-parietal coupling of EEG rhythms is in line with the hypothesis that MCI can be considered as a pre-clinical stage of the disease at group level. Functional coupling was estimated by synchronization likelihood of Laplacian-transformed EEG data at electrode pairs, which accounts for linear and non-linear components of that coupling. Cortical rhythms of interest were delta (2-4Hz), theta (4-8Hz), alpha 1 (8-10.5Hz), alpha 2 (10.5-13Hz), beta 1 (13-20Hz), beta 2 (20-30Hz), and gamma (30-40Hz). Compared to the Nold subjects, the AD patients presented a marked reduction of the synchronization likelihood (delta to gamma) at both fronto-parietal and inter-hemispherical (delta to beta 2) electrodes. As a main result, alpha 1 synchronization likelihood progressively decreased across Nold, MCI, and mild AD subjects at midline (Fz-Pz) and right (F4-P4) fronto-parietal electrodes. The same was true for the delta synchronization likelihood at right fronto-parietal electrodes (F4-P4). For these EEG bands, the synchronization likelihood correlated with global cognitive status as measured by the Mini Mental State Evaluation. The present results suggest that at group level, fronto-parietal coupling of the delta and alpha rhythms progressively becomes abnormal though MCI and mild AD. Future longitudinal research should evaluate whether the present EEG approach is able to predict the cognitive decline in individual MCI subjects.
Babiloni
Claudio
C
Dipartimento di Fisiologia Umana e Farmacologia, Università degli Studi di Roma La Sapienza, Piazzale Aldo Moro 5, 00185 Rome, Italy. claudio.babiloni@uniroma1.it
Ferri
Raffaele
R
Binetti
Giuliano
G
Cassarino
Andrea
A
Dal Forno
Gloria
G
Ercolani
Matilde
M
Ferreri
Florinda
F
Frisoni
Giovanni B
GB
Lanuzza
Bartolo
B
Miniussi
Carlo
C
Nobili
Flavio
F
Rodriguez
Guido
G
Rundo
Francesco
F
Stam
Cornelis J
CJ
Musha
Toshimitsu
T
Vecchio
Fabrizio
F
Rossini
Paolo M
PM
D000368:Aged; D000544:Alzheimer Disease / Q000503:physiopathology; D003072:Cognition Disorders / Q000503:physiopathology*; D003344:Cortical Synchronization; D004569:Electroencephalography; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology*; D006801:Humans; D008297:Male; D010296:Parietal Lobe / Q000503:physiopathology*