Neurophysiological Studies In Metachromatic Leukodistrophy

Abstract

Metachromatic Leukodystrophy (MLD) is a lysosomal storage disease caused by deficiency of Arylsulfatase A (ASA) with accumulation of cerebroside sulfate in the white matter of central and peripheral nervous system. Late infantile, juvenile and adult forms have been described according to the age of onset and severity. Several studies demonstrated the diagnostic usefulness of neurophysiological tests in leukodystrophies, but their role in the progression of the disease and/or on the therapeutic monitoring is still to be established. Four patients with late juvenile MLD were studied by means of visual, auditory, somatosensory and motor evoked potentials to monitor central nervous system involvement and by means of motor and sensory conduction velocity to monitor peripheral nerve function. All neurophysiological tests demonstrated their ability in detecting abnormalities of the related neurological system. Abnormal findings of multimodal Evoked Potentials and sensory nerve conduction study consisted of disappearance of responses while motor nerve conduction study showed quantitative data which consisted of slowing of conduction velocity. As motor nerve fibers are relatively spared in MLD patients, motor nerve conduction studies would provide a simple method for evaluating the course of the disease and therapeutical efficacy. Unfortunately no neurophysiological tests are presently available for long‐term follow‐up of CNS damage in MLD.