肌萎缩侧索硬化患者下肢分裂现象的临床及电生理研究

Clinical and electrophysiological study of lower limb split signs in amyotrophic lateral sclerosis

目的探讨肌萎缩侧索硬化(ALS)患者的分裂足现象及其与电生理检测结果之间的关联。方法前瞻性收集2021年4月至2022年12月于解放军总医院第一医学中心神经内科住院的临床确诊和拟诊为ALS的患者,收集同期因其他原因就诊于解放军总医院第一医学中心、电生理检查无异常者作为对照。通过采集ALS患者踝背伸肌和踝跖屈肌的肌力评分计算分裂腿[踝背伸肌修订版医学研究理事会肌力量表(mMRC)评分小于踝跖屈肌mMRC评分的肢体为分裂腿]的出现率,采集ALS患者踇背伸肌和踇跖屈肌的肌力评分计算分裂足(踇背伸肌mMRC评分小于踇跖屈肌mMRC评分的肢体为分裂足)的出现率。检测全部受试者腓总神经和胫神经复合肌肉动作电位(CMAP)波幅,对比ALS患者及对照者支配踝背伸肌和踝跖屈肌的运动神经元受累情况。使用受试者工作特征曲线(ROC)对腓总神经/胫神经CMAP波幅比区分ALS患者和对照者的敏感度和特异度进行分析。结果最终共收集下肢受累(表现为下肢肌肉萎缩、无力或下肢mMRC评分小于13分)的ALS患者101例,下肢肌力正常(无下肢肌肉萎缩、无力且下肢肌力mMRC评分等于13分)的对照者110名。在下肢受累的ALS患者中,踝背伸肌肌力小于踝跖屈肌肌力的患者占35.64%(36/101),踝背伸肌肌力大于踝跖屈肌肌力的患者占5.94%(6/101),踝背伸肌肌力等于踝跖屈肌肌力的患者占58.42%(59/101);踇背伸肌肌力小于踇跖屈肌肌力的患者占53.47%(54/101),踇背伸肌肌力大于踇跖屈肌肌力的患者占1.98%(2/101),踇背伸肌肌力等于踇跖屈肌肌力的患者占44.55%(45/101)。分裂腿现象的出现率与年龄(OR=0.25,95%CI 0.16~0.40,P<0.05)、病程(OR=0.52,95%CI 0.38~0.80,P<0.05)和ALS功能评分(OR=0.29,95%CI 0.12~0.67,P<0.05)呈负相关。分裂足现象的出现率与下肢症状的出现时间(OR=0.96,95%CI 0.93~0.99,P<0.05)呈负相关。与对照组相比,存在分裂足现象ALS患者的腓总神经和胫神经CMAP波幅均降低[腓总神经(6.45±2.56)mV比(3.63±1.83)mV,胫神经(12.87±4.72)mV比(9.18±6.22)mV],差异有统计学意义(t=-4.65、-3.44,均P<0.001)。与对照组相比,存在分裂足的ALS患者腓总神经/胫神经CMAP波幅比明显下降(0.54±0.24比0.36±0.18),差异有统计学意义(t=-4.31,P<0.001)。ROC曲线分析结果表明,存在分裂足现象的ALS患者与对照者的腓总神经/胫神经CMAP波幅比ROC曲线下面积为0.70,说明依靠腓总神经/胫神经CMAP波幅比区分ALS患者和对照者的准确度较低。结论在下肢受累的ALS患者中,踝背伸肌较踝跖屈肌受累重,踇背伸肌较踇跖屈肌受累重。在诊断水平上,存在分裂足的ALS患者腓总神经/胫神经CMAP波幅比对于诊断ALS的准确度较低。

Objective To investigate the association between split foot and electrophysiology in patients with amyotrophic lateral sclerosis(ALS).Methods The clinically definite or clinically probable ALS patients hospitalized in the Department of Neurology,the First Medical Center of Chinese People′s Liberation Army General Hospital from April 2021 to December 2022 were prospectively collected.From April 2021 to December 2022,patients who visited the Chinese People′s Liberation Army General Hospital for other reasons without abnormal electrophysiological examination were collected as the control group.The incidence of split leg[the limb whose modified Medical Research Council Muscle Strength Scale(mMRC)score of ankle dorsiflexors was lower than that of ankle plantarflexors]in ALS patients was calculated,and the incidence of split foot(the limb whose mMRC score of hallux dorsiflexors was lower than that of hallux plantarflexors)in ALS patients was calculated.The amplitude of compound muscle action potential(CMAP)of common peroneal nerve and tibial nerve was detected to observe the involvement of motor neurons innervating ankle dorsiflexors and ankle plantarflexors.The characteristics of split leg and split foot in ALS patients were analyzed from the perspective of muscle strength,and the characteristics of split foot in ALS patients were analyzed from the perspective of electrophysiology.Receiver operating characteristic(ROC)curve was used to analyze the sensitivity and specificity of peroneal nerve/tibial nerve CMAP amplitude ratio in distinguishing ALS patients from controls.Results A total of 101 ALS patients with lower limb involvement and 110 controls with normal lower limb muscle strength were collected.Among the 101 ALS patients with lower limb involvement,strength of ankle plantarflexors was greater than that of ankle dorsiflexors in 35.64%(36/101)patients,strength of ankle dorsiflexors was greater than that of ankle plantarflexors in 5.94%(6/101)patients,and strength of ankle plantarflexors and ankle dorsiflexors was equal in 58.42%(59/101)patients.Strength of hallux dorsiflexors was lower than that of hallux plantarflexors in 53.47%(54/101)patients,strength of hallux dorsiflexors was greater than that of hallux plantarflexors in 1.98%(2/101)patients,and the strength of hallux dorsiflexors and hallux plantarflexors was equal in 44.55%(45/101)patients.The incidence of split leg was negatively correlated with age(OR=0.25,95%CI 0.16-0.40,P<0.05),course of disease(OR=0.52,95%CI 0.38-0.80 P<0.05)and ALS functional revised scores(OR=0.29,95%CI 0.12-0.67,P<0.05).The incidence of split foot was negatively correlated with the onset time of lower limb symptoms(OR=0.96,95%CI 0.93-0.99,P<0.05).Compared with the control group,the differences of the decrease of CMAP amplitude in the common peroneal nerve and tibial nerve[the common peroneal nerve(6.45±2.56)mV vs(3.63±1.83)mV,tibial nerve(12.87±4.72)mV vs(9.18±6.22)mV]were statistically significant(t=-4.65,t=-3.44,both P<0.001)and the differences of the peroneal nerve/tibial nerve CMAP amplitude ratio(0.54±0.24 vs 0.36±0.18)decrease was statistically significant(t=-4.31,P<0.001)in patients with split foot.ROC curve analysis showed that the area under the ROC curve of CMAP amplitude ratio of common peroneal nerve/tibial nerve in ALS patients with split foot was 0.70,indicating that the accuracy of CMAP amplitude of common peroneal nerve/tibial nerve in distinguishing ALS patients from controls was low.Conclusions In ALS patients with lower limb involvement,strength of ankle dorsiflexors is weaker than that of ankle plantarflexors,and strength of hallux dorsiflexors is weaker than that of hallux plantarflexors.At the diagnostic level,the CMAP amplitude ratio of common peroneal nerve/tibial nerve in ALS patients with split foot has a lower accuracy in the diagnosis of ALS.