Jones S J, Yu Y L, Rudge P, Kriss A, Gilois C, Hirani N, Nijhawan R, Norman P, Will R
Medical Research Council, National Hospital for Nervous Diseases, Queen Square, London, U.K.
J Neurol Sci. 1987 Dec;82(1-3):55-65. doi: 10.1016/0022-510x(87)90006-2.
Somatosensory evoked potentials (SEPs) following median nerve stimulation were abnormal in 7 patients with sensory impairment due to vitamin B12 deficiency. Extensor plantar reflexes indicated a central sensory pathway lesion in 4 cases and absent tendon jerks suggested peripheral neuropathy in 4, but median nerve SEPs indicated a predominantly central lesion without marked peripheral nerve involvement in 6 and an axonal neuropathy without CNS involvement in 1. The latter had evidence of central slowing of conduction in SEPs following posterior tibial nerve stimulation. Consequently, it is suggested that the brunt of sensory pathway involvement usually falls on the CNS, although peripheral neuropathy may occur as the major abnormality in some cases. In 2 patients SEPs showed a marked improvement following treatment with vitamin B12 injections, one consistent with restored central conduction and the other with recovery from peripheral neuropathy. No peripheral or central SEP abnormalities were seen in 18 dairy-produce eating vegetarians with low vitamin B12 levels, although 6 reported mild sensory symptoms suggestive of peripheral neuropathy and 3 had corroborative clinical signs.
7例因维生素B₁₂缺乏导致感觉障碍的患者，正中神经刺激后的体感诱发电位（SEP）异常。4例患者的跖伸反射提示中枢感觉通路病变，4例患者的腱反射消失提示周围神经病变，但6例患者的正中神经SEP显示主要为中枢病变，无明显周围神经受累，1例患者为轴索性周围神经病，无中枢神经系统受累。后者在胫后神经刺激后的SEP中有中枢传导减慢的证据。因此，有人认为感觉通路受累通常主要累及中枢神经系统，尽管在某些情况下周围神经病变可能是主要异常。2例患者在注射维生素B₁₂治疗后SEP有明显改善，1例与中枢传导恢复一致，另1例从周围神经病中恢复。18例维生素B₁₂水平低的食用乳制品的素食者未发现周围或中枢SEP异常，尽管6例报告有提示周围神经病的轻度感觉症状，3例有佐证性临床体征。
