单纤维肌电图在肌萎缩侧索硬化和颈椎病鉴别诊断中的价值

Utility of single fiber electromyography in the differential diagnosis of amyotrophic lateral sclerosis and cervical spondylosis

目的探讨单纤维肌电图（SFEMG）技术在肌萎缩侧索硬化（AES）与神经根型和脊髓型颈椎病鉴别诊断中的价值。方法对61例ALS伴有MRI颈椎病表现、59例ALS不伴MRI颈椎病表现、55例神经根型和脊髓型颈椎病患者进行伸指总肌SFEMG测定，分析不同组之间SFEMG改变的特点。结果在3组患者中，平均颤抖（jitter）值分别为（81．2±25．9）、（91．6±32．4）、（40．9±11．8）μs，jitter〉55μs的百分比帆。分别为73％、80％、5％，阻滞所占百分比忆。分别为10％、20％、0，纤维密度分别为2．9±0．5、2．9±0．6、2．4±0．6。ALS伴和不伴MRI颈椎病变2组之间各参数比较差异无统计学意义。两组ALS患者合并后[平均jitter值（86．3±29．6）μs，jitter〉55μs的百分比慨。为80％，阻滞所占百分比慨。为14％，纤维密度2．9±0．5]再与颈椎病组比较，各参数均明显高于颈椎病组（分别为t=14．49，Z=8．96、7．68，t=5．83，均P=0．000）。在经随诊而确诊的18例ALS患者中，初诊时肌电图仅有1个节段的神经源性损害，在伸指总肌肌力和常规肌电图均正常情况下，有16例SFEMG可见纤维密度增高，13例jitter增宽，6例可见阻滞。结论ALS伴或不伴MRI颈椎病变的SFEMG均表现为jitter明显增宽，可伴有阻滞，纤维密度增高，与神经根型和（或）脊髓型颈椎病患者明显不同。SFEMG测定有助于ALS与颈椎病的鉴别诊断。

Objective To assess the utility of single fiber electromyography （SFEMG） in the differential diagnosis of amyotrophic lateral sclerosis （ALS） and cervical spondylotic radiculopathy and myelopathy. Methods SFEMG was performed in extensor digitorum communis muscles （EDC） of 3 groups of patients, including 61 ALS patients with findings of cervical spondylosis on MRI, 59 ALS patients with normal MRI of cervical spine, and 55 patients with cervical spondylotic radiculopathy and myelopathy. The parameters of SFEMG between different groups were compared. Results The mean jitter was （ 81.2 ± 25.9） , （91.6 ±52.4） and （40. 9 ± 11.8） μs in ALS patients with finding of cervical spondylosis on MRI, ALS patients with normal MRI of cervical spine, and patients with cervical spondylosis respectively. M50 of the percentage of jitter 〉 55 μs was 73% , 80% and 5% in the 3 groups respectively. M50 of the percentage of block was 10% , 20% and 0 in the 3 groups respectively. Fiber density was 2. 9 ± 0. 5, 2. 9 ± 0. 6 and 2. d ± 0. 6 in the 3 groups respectively. There was no significant difference in those parameters of SFEMG between the ALS with findings of cervical spondysosis and those with normal MRI. There was significant difference in those parameters of SFEMG between the patients with ALS （the mean jitter： （86. 3 ±29.6） μs; M50 of the percentage of jitter 〉55 μs： 80%; M50 of the percentage of block：14% ; fiber density： 2. 9 ± 0. 5） and those with cervical spondylosis （t = 14.49, Z = 8.96, 7. 68, t = 5.83, all P = 0. 000）. In 18 patients with ALS, conventional EMG studies showed active and chronic denervation in only 1 region at the first visit. SFEMG was performed in EDC which had normal Medical Research Council Scale and EMG. SFEMG showed increased fiber density in 16 patients, increased jitter in 13 patients and impulse block in 6 patients. Conclusion SFEMG shows significantly increased jitter and block in ALS whether there is MRI findings of cervical spondysosis or not, which can help to differentiate ALS from cervical spondysotic radiculopathy and myelopathy.