Stability of clinical condition in mild cognitive impairment is related to cortical sources of alpha rhythms: an electroencephalographic study.
Hum Brain Mapp
; 32(11): 1916-31, 2011 Nov.
Article
in En
| MEDLINE
| ID: mdl-21181798
ABSTRACT
Previous evidence has shown that resting eyes-closed cortical alpha rhythms are higher in amplitude in mild cognitive impairment (MCI) than Alzheimer's disease (AD) subjects (Babiloni et al. [2006a] Human Brain Mapp 27162-172; [2006b] Clin Neurophysiol 117252-268; [2006c] Neuroimage 29948-964; [2006d] Ann Neurol 59323-334; [2006e] Clin Neurophysiol 1171113-1129; [2006f] Neuroimage 311650-1665). This study tested the hypothesis that, in amnesic MCI subjects, high amplitude of baseline cortical alpha rhythms is related to long-term stability of global cognition on clinical follow-up. Resting electroencephalographic (EEG) data were recorded in 100 amnesic MCI subjects during eyes-closed condition. EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha1 (8-10.5 Hz), alpha2 (10.5-13 Hz), beta1 (13-20 Hz), and beta2 (20-30 Hz). Cortical EEG sources were estimated by low-resolution brain electromagnetic tomography (LORETA). Global cognition was indexed by mini mental state evaluation (MMSE) score at the time of EEG recordings (baseline) and about after 1 year. Based on the MMSE percentage difference between baseline and 1-year follow-up (MMSEvar), the MCI subjects were retrospectively divided into three arbitrary groups DECREASED (MMSEvar ≤ -4%; N = 43), STABLE (MMSEvar ≈ 0; N = 27), and INCREASED (MMSEvar ≥ +4%; N = 30). Subjects' age, education, individual alpha frequency, gender, and MMSE scores were used as covariates for statistical analysis. Baseline posterior cortical sources of alpha 1 rhythms were higher in amplitude in the STABLE than in the DECREASED and INCREASED groups. These results suggest that preserved resting cortical neural synchronization at alpha frequency is related to a long-term (1 year) stable cognitive function in MCI subjects. Future studies should use serial MMSE measurements to confirm and refine the present results.
Full text:
1
Database:
MEDLINE
Main subject:
Electroencephalography
/
Alpha Rhythm
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Cognitive Dysfunction
Limits:
Aged
/
Female
/
Humans
/
Male
Language:
En
Journal:
Hum Brain Mapp
Journal subject:
CEREBRO
Year:
2011
Type:
Article
Affiliation country:
Italy