Uncini A, Di Muzio A, Sabatelli M, Magi S, Tonali P, Gambi D
Center for Neuromuscular Diseases, University of Chieti, Italy.
Electroencephalogr Clin Neurophysiol. 1993 Jun;89(3):161-9. doi: 10.1016/0168-5597(93)90129-d.
Detection of conduction block (CB) has important clinical implications because it suggests segmental demyelination potentially reversible following treatment. There are no universally accepted criteria to define CB. We tested the sensitivity of two diagnostic criteria of partial motor CB in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) and hereditary motor-sensory neuropathy type I (HMSN I) which are thought to be the prototypes of segmental and uniform demyelination respectively. Criterion I requires > 20% drop in negative peak amplitude and area and < 15% change in duration between proximal and distal compound muscle action potentials (CMAPs). Criterion II requires > 50% drop in negative peak amplitude and area of proximal CMAP independently from temporal dispersion. Twenty-eight percent of CIDP nerves and 65% of CIDP patients had CB according to criterion I. However, 29% of nerves and 61% of patients with HMSN I also fulfilled the same criterion. Thirty-four percent of CIDP nerves and 78% of CIDP patients and none of HMSN I patients fulfilled criterion II. Criterion II has the same sensitivity as criterion I, but seems to be highly specific in diagnosis of the segmental demyelination characteristic of CIDP. Therefore this criterion should be employed, as the diagnostic tool of CB, in chronic neuropathies presenting high stimulation threshold and coexisting axonal loss.
传导阻滞（CB）的检测具有重要的临床意义，因为它提示节段性脱髓鞘，而这种脱髓鞘在治疗后可能是可逆的。目前尚无普遍接受的定义CB的标准。我们测试了慢性炎性脱髓鞘性多发性神经病（CIDP）和I型遗传性运动感觉神经病（HMSN I）患者中部分运动性CB的两种诊断标准的敏感性，这两种疾病分别被认为是节段性和弥漫性脱髓鞘的典型代表。标准I要求近端和远端复合肌肉动作电位（CMAP）之间的负向峰值幅度和面积下降>20%，持续时间变化<15%。标准II要求近端CMAP的负向峰值幅度和面积下降>50%，且与时间离散无关。根据标准I，28%的CIDP神经和65%的CIDP患者存在CB。然而，29%的HMSN I神经和61%的HMSN I患者也符合相同标准。34%的CIDP神经和78%的CIDP患者符合标准II，而HMSN I患者均不符合。标准II与标准I具有相同的敏感性，但在诊断CIDP特有的节段性脱髓鞘方面似乎具有高度特异性。因此，在存在高刺激阈值和并存轴索丢失的慢性神经病中，应采用该标准作为CB的诊断工具。
