Precocious loss of physiological sleep in a case of Creutzfeldt Jakob disease: a serial polygraphic study.

Creutzfeldt-Jakob disease (CJD) is a prion-related subacute encephalopathy producing widespread neuronal degeneration and spongiform pathological changes, especially in the neocortex. Progressive dementia, motor signs and electroencephalographic (EEG) alterations characterize the full stage of the disease. A series of eight 24-hour polygraphic recordings were carried out in the last 3 months of life of a 68-year-old female patient affected by CJD that was confirmed neuropathologically. Genetic classification demonstrated this patient to have a sporadic form of the disease. The polygraphic recordings demonstrated three types of EEG findings, as follows: 1) sustained pseudoperiodic discharges (SPD), characterized by long-lasting diffuse sequences of slow sharp waves or di- or triphasic slow waves recurring at 0.5- to 1.5-second intervals; 2) discontinuous pseudoperiodic discharges (DPD), consisting of runs of pseudoperiodic discharges (PD)(phase A) cyclically replaced at about 1-minute intervals with semi-rhythmic theta-delta activities (phase B); 3) non-rapid eye movement (NREM) sleep-like pattern, with dominant 0.5- to 4-Hz activities, less rhythmic than the EEG of phase B. Only these three EEG patterns occurred spontaneously during the repeated polygraphic sessions. The NREM sleep-like pattern was found only in the first recording, whereas the following polygraphic sessions were occupied exclusively by SPD or by a DPD pattern. SPD was associated with either a relatively high level of vigilance (along the first three recordings) or a state of alert-appearing silent immobility (following the fourth recording). During DPD, the patient was unable to accomplish any voluntary movement and fluctuated between levels of greater arousal (phase A) and lesser arousal (phase B). Just as in stage 2 coma, the fluctuations between phases A and B of DPD were synchronous with phasic modifications of muscle activity and neurovegetative functions. In particular, reinforcement of muscle tone and myoclonic spasms coincided with phase A, whereas heart rate deceleration and respiratory pauses or decrease in flow were synchronous with phase B. As EEG evolved toward the disappearance of DPD and finally to flatness, the phase-locked coordination among arousal, somatic and vegetative activities was progressively impaired and was replaced with an uncontrolled exaggeration of cardiorespiratory activity. The genetic, neuropathological and polysomnographic differences between CJD and another prion disease, fatal familial insomnia, are discussed.