GIANT SOMATOSENSORY-EVOKED POTENTIALS AND PATHOPHYSIOLOGY OF HYPEREKPLEXIA - NEUROPHYSIOLOGICAL STUDY OF ONE PATIENT

EEG during wakefulness and sleep and somatosensory evoked potentials f rom the median nerve were recorded in a 3 year-old boy with hyperekple xia 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 abnorm ally high amplitude over the centroparietal regions. Pathophysiologica l mechanisms of hyperekplexia are discussed and the existence of sympt omatic forms is suggested.