title: Visual and spectral analysis of sleep EEG in acute hemispheric stroke.
abstract: BACKGROUND
  Reports on the effects of focal hemispheric damage on sleep EEG are rare and contradictory.
  
  
  METHODS
  Twenty patients (mean age +/- SD 53 +/- 14 years) with a first acute hemispheric stroke and no sleep apnea were studied. Stroke severity [National Institute of Health Stroke Scale (NIHSS)], volume (diffusion-weighted brain MRI), and short-term outcome (Rankin score) were assessed. Within the first 8 days after stroke onset, 1-3 sleep EEG recordings per patient were performed. Sleep scoring and spectral analysis were based on the central derivation of the healthy hemisphere. Data were compared with those of 10 age-matched and gender-matched hospitalized controls with no brain damage and no sleep apnea.
  
  
  RESULTS
  Stroke patients had higher amounts of wakefulness after sleep onset (112 +/- 53 min vs. 60 +/- 38 min, p < 0.05) and a lower sleep efficiency (76 +/- 10% vs. 86 +/- 8%, p < 0.05) than controls. Time spent in slow-wave sleep (SWS) and rapid eye movement (REM) sleep and total sleep time were lower in stroke patients, but differences were not significant. A positive correlation was found between the amount of SWS and stroke volume (r = 0.79). The slow-wave activity (SWA) ratio NREM sleep/wakefulness was lower in patients than in controls (p < 0.05), and correlated with NIHSS (r = -0.47).
  
  
  CONCLUSIONS
  Acute hemispheric stroke is accompanied by alterations of sleep EEG over the healthy hemisphere that correlate with stroke volume and outcome. The increased SWA during wakefulness and SWS over the healthy hemisphere contralaterally to large strokes may reflect neuronal hypometabolism induced transhemispherically (diaschisis).
authors.affiliation: Department of Neurology, Inselspital University Hospital Bern, Bern, Switzerland.
authors.forename: Caroline
authors.initials: C
authors.lastname: Müller
authors.forename: Peter
authors.initials: P
authors.lastname: Achermann
authors.forename: Matthias
authors.initials: M
authors.lastname: Bischof
authors.forename: Arto C
authors.initials: AC
authors.lastname: Nirkko
authors.forename: Corinne
authors.initials: C
authors.lastname: Roth
authors.forename: Claudio L
authors.initials: CL
authors.lastname: Bassetti
mesh_terms: D004569:Electroencephalography; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012815:Signal Processing, Computer-Assisted; D012890:Sleep / Q000502:physiology*; D012895:Sleep, REM / Q000502:physiology; D020521:Stroke / Q000503:physiopathology*; D014851:Wakefulness / Q000502:physiology