title: Correlation between sleep and cognitive functions after hemispheric ischaemic stroke.
abstract: BACKGROUND
  The aim of this study was to test the hypothesis of a link between sleep and cognitive functions, particularly memory and attention, after stroke.
  
  
  METHODS
  We studied 11 consecutive patients with first-ever hemispheric ischaemic stroke within eight days after symptoms onset and nine of them at least three months after stroke. Sleep EEG was recorded with a portable system. Cognitive functions were assessed using a standardized battery of tests allowing the estimation of the most relevant domains of cognition. Five age-matched healthy subjects served as controls.
  
  
  RESULTS
  The patients were aged 43 +/- 12 years (18-59). In five patients stroke was right-sided and in six patients left-sided. In the acute stroke phase a correlation between attention and amounts of slow wave sleep (SWS), Rapid eye movement (REM) sleep and sleep efficiency was found. In the recovery phase verbal/figural memory and attention significantly improved in most patients. Furthermore, an association between (i) verbal/figural (non-verbal) memory and amounts of SWS, REM sleep and sleep efficiency, and between (ii) attention and sleep efficiency was observed.
  
  
  CONCLUSIONS
  The results point to a link between sleep and cognitive functions and their recovery after hemispheric stroke. Further studies are needed to determine the specific nature of this link.
authors.affiliation: Department of Neurology, University Hospital of Zurich, Zurich, Switzerland.
authors.forename: M M
authors.initials: MM
authors.lastname: Siccoli
authors.forename: N
authors.initials: N
authors.lastname: Rölli-Baumeler
authors.forename: P
authors.initials: P
authors.lastname: Achermann
authors.forename: C L
authors.initials: CL
authors.lastname: Bassetti
mesh_terms: D000293:Adolescent; D000328:Adult; D003071:Cognition / Q000502:physiology*; D004569:Electroencephalography; D005260:Female; D007839:Functional Laterality; D006801:Humans; D020925:Hypoxia-Ischemia, Brain / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D020127:Recovery of Function / Q000502:physiology*; D012890:Sleep / Q000502:physiology*; D020521:Stroke / Q000503:physiopathology*