title: Age-dependent changes in sleep EEG topography.
abstract: OBJECTIVE
  To assess age-related topographic changes in the sleep electroencephalogram (EEG).
  
  
  METHODS
  The sleep EEG records of young (mean age, 22.3 years) and middle-aged (mean age, 62.0 years) healthy men were compared. The EEG was obtained from 3 bipolar derivations (frontal-central (FC), central-parietal (CP), and parietal-occipital (PO)) along the antero-posterior axis.
  
  
  RESULTS
  The total sleep time, sleep efficiency, stage 2 and slow wave sleep (SWS) were lower in the middle-aged group, while sleep latency, stage 1 and wakefulness after sleep onset were higher. Spectral analysis documented the age-related reduction of EEG power in non-REM sleep (0.25-14 Hz), and REM sleep (0.75-10 Hz). However, the reduction was not uniform over the 3 derivations, but was most pronounced in the anterior derivation (FC) in the theta (both sleep states) and high-alpha/low-sigma bands (non-REM sleep).
  
  
  CONCLUSIONS
  These changes can be interpreted as age-related shifts of power from the anterior (FC) towards the middle derivation (CP). Aging not only reduces power in the sleep EEG, but causes frequency-specific changes in the brain topography. The results are consistent with the notion of sleep as a local process.
authors.affiliation: Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland. landolt@pharma.unizh.ch
authors.forename: H P
authors.initials: HP
authors.lastname: Landolt
authors.forename: A A
authors.initials: AA
authors.lastname: Borbély
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology*; D001921:Brain / Q000502:physiology; D004569:Electroencephalography; D006801:Humans; D008297:Male; D008875:Middle Aged; D012890:Sleep / Q000502:physiology*; D012894:Sleep Stages / Q000502:physiology; D012895:Sleep, REM / Q000502:physiology; D013997:Time Factors