title: Rivastigmine effects on EEG spectra and three-dimensional LORETA functional imaging in Alzheimer's disease.
abstract: 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.
authors.affiliation: The KEY Institute for Brain-Mind Research, University Hospital of Psychiatry, University of Zurich, Lenggstrasse 31, CH-8032 Zurich, Switzerland. lgianott@key.uzh.ch
authors.forename: Lorena R R
authors.initials: LR
authors.lastname: Gianotti
authors.forename: Gabriella
authors.initials: G
authors.lastname: Künig
authors.forename: Pascal L
authors.initials: PL
authors.lastname: Faber
authors.forename: Dietrich
authors.initials: D
authors.lastname: Lehmann
authors.forename: Roberto D
authors.initials: RD
authors.lastname: Pascual-Marqui
authors.forename: Kieko
authors.initials: K
authors.lastname: Kochi
authors.forename: Ursula
authors.initials: U
authors.lastname: Schreiter-Gasser
mesh_terms: 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
chemical_list: D002800:Cholinesterase Inhibitors; D018696:Neuroprotective Agents; D048448:Phenylcarbamates; D000068836:Rivastigmine