ABSTRACT
Objective To investigate the loss of motor unit and it's influencing factors in the lower motor neurons after middle cerebral artery infarction. Method Forty patients with first onset and unilateral middle cerebral artery infarction were divided into cortical-basal ganglia(26)and basal ganglia(14)groups and 10 healthy controls were served as control group.All included patients were scored by National Institute of Health stroke scale(NIHSS),modified Rankin scale (mRS), Fugl-Meyer Assessment (FMA) at 48 hours of admission. Nerve conduction study on the limb and motor unit number estimation (MUNE) on abductor pollicis brevis were performed at 2-4 weeks after onset, and the data of single motor action potential (SMUAP) were collected. SPSS 20.0 software was used to statistical analysis. Result The MUNE on were significantly lower and the amplitude and area of SMUAP were significantly increased in ipsilateral than contralateral sides (cortical-basal ganglia group:95.85±26.82 vs. 143.65±38.86, P<0.001; basal ganglia group: 126.71± 44.13 vs. 157.36±56.72, P=0.001). The affected MUNE was significantly decreased in the cortex-basal ganglia than in basal ganglia groups (95.85±26.82 vs.161.40±48.90,P=0.027). The MUNE was negatively correlated with NIHSS score (r=-0.362,P=0.022)and mRS score(r=-0.339,P=0.032).NIHSS score(β=-1.603,P=0.032,95%CI:-3.064~-0.142)and mRS score(OR=2.885,P=0.025,95%CI:1.139~7.158)on admission could predict the loss of MUNE on the affected side. Conclusion This study reveals the loss of motor unit and the compensation of remained motor unit on the affected side after middle cerebral artery infarction,NIHSS score and mRS score on admission may predict the loss of MUNE after stroke.