ACCURACY AND RELIABILITY OF PERIODIC SHARP WAVE COMPLEXES IN CREUTZFELDT-JAKOB-DISEASE

Objective: To assess the sensitivity, specificity, and interobserver r eliability of periodic sharp wave complexes in the electroencephalogra ms of patients with Creutzfeldt-Jakob disease. Design: Sixty-eight ele ctroencephalograms in 29 patients who had been suspected of having Cre utzfeldt-Jakob disease were reanalyzed by an investigator who was unaw are of the clinical data. The incidence of periodic sharp wave complex es in neuropathologically confirmed Creutzfeldt-Jakob disease vs progr essive dementia other than Creutzfeldt-Jakob disease was assessed. Bli nded electroencephalogram analysis was performed by a second investiga tor. The interobserver reliability was assessed by the kappa value. Se tting: University hospital, base of the German National Creutzfeldt-Ja kob Disease Surveillance Study. Patients: Fifteen patients with neurop athologically confirmed Creutzfeldt-Jakob disease and 14 patients who had been suspected of having Creutzfeldt-Jakob disease because of rapi dly progressive dementia but in whom other dementias were diagnosed by unblinded investigators based on clinical and electroencephalographic criteria. Main Outcome Measure: Sensitivity and specifity of periodic sharp wave complexes assessed by their incidence in Creutzfeldt-Jakob disease vs other dementias. Interobserver reliability of periodic sha rp wave complexes was expressed by the kappa value. Results: For perio dic sharp wave complexes, blinded electroencephalographic analysis res ulted in a sensitivity and a specificity of 67% and 86%, respectively. Interobserver reliability was excellent (kappa=0.95). Conclusion: Thi s blinded electroencephalographic study in Creutzfeldt-Jakob disease c onfirms the high diagnostic value of electroencephalography, as previo usly reported by open studies.