Sensory evoked potentials in Creutzfeldt-Jakob disease

Eight patients presenting with intermediate or terminal evolution of Creutzfeldt-Jakob disease (CJD) were investigated by means of evoked potentials. Fifteen age-matched healthy subjects served as controls. The 8 patients had well-recognizable but simplified flash evoked potentials (FEPs) consisting of P1 and N2 waves followed by a single late positive (P2) deflection. Enlarged FEPs were found in 2 of the 8 patients. The somatosensory central conduction time was normal in 3 of 5 patients, and it resulted in upper normal limits or was moderately slowed in 2 patients. No enlarged somatosensory scalp potentials were recorded. Cortical somatosensory responses were characterized by an unrecognizable (4 patients) or delayed (2 patients) N33 wave. Brainstem auditory evoked responses, recorded in 6 patients, were normal. In CJD very important functional impairment of the sensory cortical areas is associated with absent or mild dysfunction of the subcortical sensory pathways.