Electrophysiological characterization of adult-onset Niemann-Pick type C disease.

In infantile and juvenile Niemann-Pick type C (NPC) disease electrophysiological studies have shown central (CNS) and peripheral (PNS) nervous system abnormalities. However, an extensive electrophysiological evaluation of CNS and PNS in adult form of NPC is still lacking. The aim of the study is to assess in adult-onset NPC disease the involvement of CNS and PNS by a multimodal electrophysiological approach. Three patients affected by adult form of NPC disease underwent electrophysiological evaluation including nerve conduction study (NCS), magnetic motor (MEPs), visual (VEPs), somatosensory (SSEPs) and brainstem auditory (BAEPs) evoked potentials. NCS, MEPs, VEPs and upper limb SSEPs were normal. Lower limb SSEPs were abnormal in all patients and abnormalities were consistent with a length-dependent process affecting the central somatosensory pathway. BAEPs were abnormal in all patients with both peripheral and central impairment of auditory pathway. Our electrophysiological findings suggest that auditory and lower limb somatosensory pathways are constantly affected in adult-onset form of NPC disease. The involvement of PNS, pyramidal, visual and upper limb somatosensory pathways might occur later during the course of disease.