Giant somatosensory evoked potentials and pathophysiology of hyperekplexia. Neurophysiological study of one patient

Summary EEG during wakefulness and sleep and somatosensory evoked potentials from the median nerve were recorded in a 3 year-old boy with hyperekplexia and his close relatives (parents and two sisters). Centro-temporal spikes during sleep were found in the patient and in the older sister, while somatosensory evoked potentials, in the patient, showed abnormally high amplitude over the centroparietal regions. Pathophysiological mechanisms of hyperekplexia are discussed and the existence of symptomatic forms is suggested.