The significance of cyclic EEG changes in Creutzfeldt-Jakob disease: prognostic value of their course in 9 patients.

The diagnostic value of the EEG in Creutzfeldt-Jakob disease is based not only on the presence of a typical pattern of periodic discharges but also on the appearance of cyclic changes in the EEG. The pattern of the cyclic EEG changes was analysed in 9 patients with Creutzfeldt-Jakob disease. The changes appear when the level of wakefulness is reduced. The alternating pattern rate increases as the disease progresses and accounts for as much as 100 per cent of the tracing when the patient is in coma. During the cyclic changes the cardiorespiratory rate is always higher in phase A than in phase B. Hypertonic fits and most myoclonic jerks are present only in the A-phase, whereas partial myoclonus and fasciculations are present in both phases. The cyclic change pattern in Creutzfeldt-Jakob disease reveals a progressive. The cyclic change pattern in Creutzfeldt-Jakob disease reveals a progressive, serious involvement of the waking system.