title: EEG synchronization in mild cognitive impairment and Alzheimer's disease.
abstract: OBJECTIVE
  To compute the synchronization likelihood of multichannel electroencephalogram (EEG) data in Alzheimer (AD) patients, subjects with mild cognitive impairment (MCI) and subjects with subjective memory complaints (SC).
  
  
  METHODS
  EEGs (200 Hz sample frequency; 21 channels; average reference) were recorded in 10 AD patients (two males; age 76.2; SD 9.36; range 59-86), 17 subjects with MCI (eight males; age 77.41; SD 6.25; range 62-88) and 20 subjects with SCI (11 males; age 68.9; SD 12.96; range: 51-89). The synchronization likelihood, a novel type of coherence measure, was computed, comparing each channel with all other channels, for the 2-6, 6-10, 10-14, 14-18, 18-22 and 22-50 Hz band.
  
  
  RESULTS
  The synchronization likelihood was significantly decreased in the 14-18 and 18-22 Hz band in AD patients compared with both MCI subjects and healthy controls. Lower beta band synchronization correlated with lower Mini-Mental state examination (MMSE) scores.
  
  
  CONCLUSIONS
  Loss of beta band synchronization occurs early in mildly affected AD patients and correlates with cognitive impairment.
authors.affiliation: Department of Clinical Neurophysiology, VU University Medical Centre, Amsterdam, the Netherlands. cj.stam@vmc.nl
authors.forename: C J
authors.initials: CJ
authors.lastname: Stam
authors.forename: Y
authors.initials: Y
authors.lastname: van der Made
authors.forename: Y A L
authors.initials: YA
authors.lastname: Pijnenburg
authors.forename: Ph
authors.initials: P
authors.lastname: Scheltens
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000503:physiopathology*; D001611:Beta Rhythm; D003072:Cognition Disorders / Q000503:physiopathology*; D003344:Cortical Synchronization; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000503:physiopathology*; D008875:Middle Aged