title: Accuracy and reliability of periodic sharp wave complexes in Creutzfeldt-Jakob disease.
abstract: OBJECTIVE
  To assess the sensitivity, specificity, and interobserver reliability of periodic sharp wave complexes in the electroencephalograms of patients with Creutzfeldt-Jakob disease.
  
  
  METHODS
  Sixty-eight electroencephalograms in 29 patients who had been suspected of having Creutzfeldt-Jakob disease were reanalyzed by an investigator who was unaware of the clinical data. The incidence of periodic sharp wave complexes in neuropathologically confirmed Creutzfeldt-Jakob disease vs progressive dementia other than Creutzfeldt-Jakob disease was assessed. Blinded electroencephalogram analysis was performed by a second investigator. The interobserver reliability was assessed by the kappa value.
  
  
  METHODS
  University hospital, base of the German National Creutzfeldt-Jakob Disease Surveillance Study.
  
  
  METHODS
  Fifteen patients with neuropathologically confirmed Creutzfeldt-Jakob disease and 14 patients who had been suspected of having Creutzfeldt-Jakob disease because of rapidly progressive dementia but in whom other dementias were diagnosed by unblinded investigators based on clinical and electroencephalographic criteria.
  
  
  METHODS
  Sensitivity and specificity of periodic sharp wave complexes assessed by their incidence in Creutzfeldt-Jakob disease vs other dementias. Interobserver reliability of periodic sharp wave complexes was expressed by the kappa value.
  
  
  RESULTS
  For periodic sharp wave complexes, blinded electroencephalographic analysis resulted in a sensitivity and a specificity of 67% and 86%, respectively. Interobserver reliability was excellent (kappa = 0.95).
  
  
  CONCLUSIONS
  This blinded electroencephalographic study in Creutzfeldt-Jakob disease confirms the high diagnostic value of electroencephalography, as previously reported by open studies.
authors.affiliation: Department of Clinical Neurophysiology, Georg-August University, Göttingen, Germany.
authors.forename: B J
authors.initials: BJ
authors.lastname: Steinhoff
authors.forename: S
authors.initials: S
authors.lastname: Räcker
authors.forename: G
authors.initials: G
authors.lastname: Herrendorf
authors.forename: S
authors.initials: S
authors.lastname: Poser
authors.forename: S
authors.initials: S
authors.lastname: Grosche
authors.forename: I
authors.initials: I
authors.lastname: Zerr
authors.forename: H
authors.initials: H
authors.lastname: Kretzschmar
authors.forename: T
authors.initials: T
authors.lastname: Weber
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000503:physiopathology; D007562:Creutzfeldt-Jakob Syndrome / Q000175:diagnosis* / Q000503:physiopathology; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010507:Periodicity; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity