Peripheral Nerve Function in Vitamin B12 Deficiency

INVOLVEMENT of the spinal cord in patients with addisonian pernicious anemia is well known¹,²and the defect has been clinically related to vitamin B₁₂deficiency.³⁻⁵Although peripheral nerve dysfunction has also been described in this condition,⁶,⁷its documentation and relationship to vitamin B₁₂deficiency is not completely established.⁸,⁹ Recently, techniques have been developed for the measurement of the conduction velocity in the largest motor¹⁰and sensory fibers¹¹,¹²in human peripheral nerves. These methods offer a sensitive index for assessing peripheral nerve function if the techniques are standardized and individual values compared with those of normals in the same age range.¹³These procedures are well tolerated by patients and testing can be repeated at various time intervals. Improvement or deterioration of nerve function can thus be determined. Pathological processes which affect large fibers are readily studied by these techniques since the