SOMATOSENSORY-EVOKED MAGNETIC-FIELDS FROM PRIMARY SENSORIMOTOR CORTEXIN JUVENILE NEURONAL CEROID-LIPOFUSCINOSIS

The present study evaluated neurophysiologic function of the primary s ensorimotor cortex in juvenile neuronal ceroid lipofuscinosis. A 122-c hannel magnetometer, which allowed studies of the somatosensory system in millimeter and millisecond precision, was used to record somatosen sory evoked magnetic fields to median nerve stimulation from 10 patien ts and their matched control subjects. In both patients and controls, the somatosensory evoked magnetic fields from primary sensorimotor are a typically consisted of N20m, P35m, and P60m deflections. In the pati ents, N20m was significantly delayed, whereas P35m peaked earlier than in the control subjects. The source strengths for N20m and P35m were greater in the patients than in the controls. Both deflections showed a significant positive correlation with the disease duration: the sour ces were stronger in the older patients than in the younger ones. P60m deflections were normal or reduced in the patients. The results indic ated increased thalamocortical excitability in the sensorimotor cortex in juvenile neuronal ceroid lipofuscinosis.