Rivastigmine effects on EEG spectra and three-dimensional LORETA functional imaging in Alzheimer's disease.
OBJECTIVE
The objective of the study is to investigate the electrocortical and the global cognitive effects of 3 months rivastigmine medication in a group of mild to moderate Alzheimer's disease patients.


METHODS
Multichannel EEG and cognitive performances measured with the Mini Mental State Examination in a group of 16 patients with mild to moderate Alzheimer's Disease were collected before and 3 months after the onset of rivastigmine medication.


RESULTS
Spectral analysis of the EEG data showed a significant power decrease in the delta and theta frequency bands during rivastigmine medication, i.e., a shift of the power spectrum towards 'normalization'. Three-dimensional low resolution electromagnetic tomography (LORETA) functional imaging localized rivastigmine effects in a network that includes left fronto-parietal regions, posterior cingulate cortex, bilateral parahippocampal regions, and the hippocampus. Moreover, a correlation analysis between differences in the cognitive performances during the two recordings and LORETA-computed intracortical activity showed, in the alpha1 frequency band, better cognitive performance with increased cortical activity in the left insula.


CONCLUSIONS
The results point to a 'normalization' of the EEG power spectrum due to medication, and the intracortical localization of these effects showed an increase of cortical activity in frontal, parietal, and temporal regions that are well-known to be affected in Alzheimer's disease. The topographic convergence of the present results with the memory network proposed by Vincent et al. (J. Neurophysiol. 96:3517-3531, 2006) leads to the speculation that in our group of patients, rivastigmine specifically activates brain regions that are involved in memory functions, notably a key symptom in this degenerative disease.
Gianotti
Lorena R R
LR
The KEY Institute for Brain-Mind Research, University Hospital of Psychiatry, University of Zurich, Lenggstrasse 31, CH-8032 Zurich, Switzerland. lgianott@key.uzh.ch
Künig
Gabriella
G
Faber
Pascal L
PL
Lehmann
Dietrich
D
Pascual-Marqui
Roberto D
RD
Kochi
Kieko
K
Schreiter-Gasser
Ursula
U
D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000188:drug therapy* / Q000473:pathology / Q000523:psychology; D002540:Cerebral Cortex / Q000473:pathology; D002800:Cholinesterase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D003072:Cognition Disorders / Q000523:psychology; D004569:Electroencephalography; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D018696:Neuroprotective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D048448:Phenylcarbamates / Q000494:pharmacology* / Q000627:therapeutic use; D011597:Psychomotor Performance / Q000187:drug effects; D000068836:Rivastigmine
D002800:Cholinesterase Inhibitors; D018696:Neuroprotective Agents; D048448:Phenylcarbamates; D000068836:Rivastigmine