title: Reduced N-acetylaspartate to creatine ratio in the posterior cingulate correlates with cognition in Alzheimer's disease following four months of rivastigmine treatment.
abstract: OBJECTIVE
  To determine whether 4 months of rivastigmine treatment would result in metabolic changes and whether metabolic changes correlate with changes in cognition in people with Alzheimer's disease (AD).
  
  
  METHODS
  Magnetic resonance spectra were acquired from the posterior cingulate cortex of subjects with AD at 3 T. Magnetic resonance imaging scans and cognitive tests were performed before and 4 months after the beginning of the treatment. Metabolite concentrations were quantified and used to calculate the metabolite ratios.
  
  
  RESULTS
  On average, the N-acetylaspartate/creatine (NAA/Cr) ratio decreased by 12.7% following 4 months of rivastigmine treatment, but changes in the NAA/Cr ratio correlated positively with changes in Mini-Mental State Examination scores.
  
  
  CONCLUSIONS
  This positive correlation between changes in NAA/Cr and changes in cognitive performance suggests that the NAA/Cr ratio could be an objective indicator of a response to rivastigmine treatment.
authors.affiliation: Centre for Functional and Metabolic Mapping (CFMM), Robarts Research Institute, and Department of Medical Biophysics, University of Western Ontario, London, Ont., Canada.
authors.forename: Jacob
authors.initials: J
authors.lastname: Penner
authors.forename: Jennie L
authors.initials: JL
authors.lastname: Wells
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Borrie
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Woolmore-Goodwin
authors.forename: Robert
authors.initials: R
authors.lastname: Bartha
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000188:drug therapy* / Q000378:metabolism; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D002800:Cholinesterase Inhibitors / Q000627:therapeutic use*; D003072:Cognition Disorders / Q000188:drug therapy* / Q000378:metabolism; D003401:Creatine / Q000378:metabolism*; D005260:Female; D006179:Gyrus Cinguli / Q000378:metabolism*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009483:Neuropsychological Tests; D048448:Phenylcarbamates / Q000627:therapeutic use*; D000068836:Rivastigmine
chemical_list: D002800:Cholinesterase Inhibitors; D048448:Phenylcarbamates; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D000068836:Rivastigmine