Sources of cortical rhythms change as a function of cognitive impairment in pathological aging: a multicenter study

• Published in: Clinical neurophysiology Vol. 117; no. 2; pp. 252 - 268
• Main Authors: Babiloni, Claudio, Binetti, Giuliano, Cassetta, Emanuele, Forno, Gloria Dal, Percio, Claudio Del, Ferreri, Florinda, Ferri, Raffaele, Frisoni, Giovanni, Hirata, Koichi, Lanuzza, Bartolo, Miniussi, Carlo, Moretti, Davide V., Nobili, Flavio, Rodriguez, Guido, Romani, Gian Luca, Salinari, Serenella, Rossini, Paolo M.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 01.02.2006; Elsevier Science
• Subjects: Aged; Aging - pathology; Alpha rhythm; Alzheimer Disease - physiopathology; Biological and medical sciences; Brain Mapping; Case-Control Studies; Cerebral Cortex - physiopathology; Cognition Disorders - physiopathology; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Electrodiagnosis. Electric activity recording; Electroencephalography (EEG); Electroencephalography - classification; Electroencephalography - methods; Female; Humans; Investigative techniques, diagnostic techniques (general aspects); Low resolution brain electromagnetic tomography (LORETA); Male; Medical sciences; Mental Status Schedule - statistics & numerical data; Middle Aged; Mild Alzheimer's disease (mild AD); Mild cognitive impairment (MCI); Nervous system; Neurology; Retrospective Studies; Signal Processing, Computer-Assisted; Spectrum Analysis; Statistics as Topic; Alpha rhythm; Mild Alzheimer's disease (mild AD); Electroencephalography (EEG); Low resolution brain electromagnetic tomography (LORETA); Mild cognitive impairment (MCI); Human; Nervous system diseases; Delta rhythm; Cognitive disorder; Alzheimer disease; Multicenter study; Electrophysiology; Electroencephalography; Cerebral disorder; Eye; Visual system; Electrodiagnosis; Clinical stage; Central nervous system disease; Tomography; Nonlinearity; Degenerative disease; mild cognitive impairment; Elderly
• ISSN: 1388-2457; 1872-8952
• DOI: 10.1016/j.clinph.2005.09.019

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