Serial waking-sleep EEGs and evolution of somatosensory potentials in Creutzfeldt-Jakob disease

We have analysed the serial sleep and waking EEGs of 3 patients with Creutzfeldt-Jakob disease (CJD), demonstrated by pathology studies. The presence of periodic complexes (PCs) was a constant finding in all the records, including those made on admission (1-3 months after the onset of symptoms) although at this stage the PCs were not as persistent of generalized as in the more advanced stages. The physiological states of sleep were replaced by cyclic changes which initially consisted of phases with PCs alternating with theta-delta activity. As the disease progressed, brief periods of suppression of background rhythm were added, followed by slower PCs. In case 3, the SEPs obtained on stimulating the median nerves were normal at the first test. However, 17 days later a further test revealed two types of abnormality. On the one hand, using a non-cephalic reference, the SEPs were of lesser amplitude and had become disorganized. On the other hand, with a cephalic reference, a potential of enormous amplitude was obtained unilaterally. On the contrary, the SEPs obtained with a cephalic reference on stimulating the posterior tibial nerves were of small amplitude and disorganized. These findings, in combination with the EEG anomalies, suggest a progressive dysfunction of the cerebral cortex. The recording of a giant potential only at C'3-Fz on stimulating the median nerve could be related to a pathological facilitation of long-loop transcortical stretch reflexes of the hand.