摘要目的：探讨分裂手现象在肌萎缩侧索硬化（ amyotrophic lateral sclerosis，ALS）患者诊断和鉴别诊断中的价值。方法对90例ALS患者、41例其他神经肌肉病患者和71名健康对照者进行常规神经传导检测。比较3组受试者分别于拇短展肌、第一骨间背侧肌（ FDI ）和小指展肌记录的复合肌肉动作电位（CMAP）波幅、CMAP波幅比、CMAP波幅差值和分裂手指数（split-hand index，SI）的差异。结果 ALS患者拇短展肌／小指展肌CMAP波幅比[0.44（0.44）]低于其他神经肌肉病患者[1.13（0.87）；z＝6.967， P＜0.01]和健康对照组[0．99（0．42）；z＝7.687， P＜0.01]，差异有统计学意义；ALS患者FDI／小指展肌CMAP波幅比[0.79（0.46）]低于健康对照组[1.23（0.39）]，差异有统计学意义（z＝5.899，P＜0.01），而与其他神经肌肉病患者[0.93（0.62）]相比差异无统计学意义（z＝1.737，P＝0.081）；ALS患者[2.42（3.14）]SI低于其他神经肌肉病患者[10.10（6．54）； q＝7.947， P＜0.05]和健康对照组[17．93（8．32）；q＝10.827， P＜0.05]，差异有统计学意义。 SI＜5.2具有较高的敏感度和特异度，分别为83.33％和96.43％。结论分裂手现象是ALS患者特异的临床表现。SI＜5.2可有效鉴别ALS与其他有类似临床表现的神经肌肉疾病，有助于ALS早期诊断。

abstractsObjective To investigate the diagnostic value of the split-hand sign in amyotrophic lateral sclerosis ( ALS).Methods Ninety ALS patients, 41 patients with other neuromuscular disorders and 71 normal controls were recruited for conventional nerve conduction study.Compound muscle action potential ( CMAP) amplitude recorded from abductor pollicis brevis ( APB) , abductor digiti minimi ( ADM) and first dorsal interosseous (FDI), CMAP amplitude ratios, CMAP amplitude differences and split-hand index ( SI) were analyzed.Results The APB/ADM CMAP amplitude ratio was significantly lower in the ALS patients (0.44(0.44)) than that in the patients with other neuromuscular disorders (1.31(0.87);z=6.967, P<0.01) and the normal controls (0.99(0.42);z=7.687, P<0.01).The FDI/ADM CMAP amplitude ratio was significantly decreased in the ALS patients ( 0.79 ( 0.46 ) ) compared with that in the normal controls ( 1.23 ( 0.39 ); z =5.899, P <0.01 ).The FDI/ADM CMAP amplitude ratio was comparable between the ALS patients and the patients with other neuromuscular disorders ( 0.93 ( 0.62 );z=1.737,P=0.081).SI was significantly lower in the ALS patients (2.42 (3.14)) than that in the patients with other neuromuscular disorders (10.10(6.54);q=7.947, P<0.05) and the normal controls (17.93(8.32);q=10.827, P<0.05).SI <5.2 can help differentiate ALS from mimic disorders, with a sensitivity of 83.33% and specificity of 96.43%.Conclusions The split-hand sign appears to be a specific feature of ALS.SI robustly differentiates ALS from mimic disorders and potentially facilitates an earlier diagnosis of ALS.