Nerve Conduction studies of Sunacute combined Degeneration

ABSTRACT

OBJECT There have been some controversies about the nature of peripheral neuropathy in patients with subacute comblned degeneration. Mayer concluded that the neuropathy was essentially demyelinating. And other reports which were based on pathologic or electrophyslological filldings have been saying axonopathy. We tried to find the nature of perlpheral neuropathy by doing conventional nerve conduction studies in 19 patients with subacute combined degeneration. SUBJECT AND METHOD: We included 19 patients with subacute combined degeneration, who were diagnosed by decreased serum vitamin B12(200pg/ml) and abnormal neurologic symptoms and/or signs. The patients were between 26 and 86 years of age. Eleven of them were male. We performed conventional nerve conduction studies Including H-reflex, When nerve conduction parameters deviated by more than 2SD from the normal mean value, they were consider as abnormal. RESULTS: nerve conduction studies were abnormal in 13/19. 11/13 with abnormal nerve conduction studies showed the pattern of peripheral polyneuropathy. Ten of them showed decreased amplitudes of sensory nerve action potentials or compound nerve action potentials with/wlthout mild slowing of nerve condcution. The abnormalities of the three patients with nerve conduction parameters of demyelinating range were confined to the distal segments of the median nerves. CONCLUSION: We thought that the results of the nerve conduction studies of our cases were compatible with axonopathy rather than demyelinopathy as a principal ]esion of the peripheral nervous system.