title: Conversion of mild cognitive impairment patients in Alzheimer's disease: prognostic value of Alpha3/Alpha2 electroencephalographic rhythms power ratio.
abstract: BACKGROUND
  The increase in electroencephalogram (EEG) alpha3/alpha2 frequency power ratio has been demonstrated as a biomarker characteristic of subjects with mild cognitive impairment (MCI) who will develop Alzheimer's disease (AD).
  
  
  METHODS
  Seventy-four adult subjects with MCI underwent clinical and neuropsychological evaluation, EEG recording, and high-resolution 3D magnetic resonance imaging (MRI). This group has been evaluated after a three years follow-up. Twenty-seven of these subjects underwent perfusion single-photon emission computed tomography (SPECT) evaluation also. Increasing alpha3/alpha2 power ratio, was computed for each subject. Differences in EEG markers, cortical thickness, brain perfusion among the groups were estimated.
  
  
  RESULTS
  In the higher alpha3/alpha2 frequency power ratio group, greater memory impairment was correlated with greater cortical atrophy and lower perfusional rate in the temporo-parietal cortex. After a follow-up of three years, these patients converted in AD.
  
  
  CONCLUSIONS
  High EEG upper/low alpha power ratio was associated with cortical thinning and lower perfusion in the temporo-parietal lobe. Moreover, atrophy and lower perfusion rate were both significantly correlated with memory impairment in MCI subjects. The increase of EEG upper/low alpha frequency power ratio could be useful for identifying individuals at risk for progression to AD dementia and may be of value in the clinical context.
authors.affiliation: Alzheimer' Disease Rehabilitation Unit, IRCCS S. Giovanni di Dio Fatebenefratelli, Brescia, Italy. davide.moretti@afar.it.
authors.forename: D V
authors.initials: DV
authors.lastname: Moretti
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000513:Alpha Rhythm / Q000502:physiology*; D000544:Alzheimer Disease / Q000150:complications / Q000473:pathology*; D001284:Atrophy / Q000473:pathology; D015415:Biomarkers / Q000032:analysis; D001921:Brain / Q000473:pathology* / Q000503:physiopathology*; D060825:Cognitive Dysfunction / Q000150:complications / Q000473:pathology*; D004569:Electroencephalography / Q000379:methods; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009483:Neuropsychological Tests
chemical_list: D015415:Biomarkers