Clinical Study Of Electrophysiological Changes Of Somatic,Sympathetic Nerves And Skeletal Muscles In Patients With Stroke

Objective:To investigate the electrophysiological changes of somatic,sympathetic nerves and skeletal muscle in patients with stroke.Methods:Standard motor nerve conduction examination was performed in bilateral median,ulnar,radial,musculocutaneous,axillary,suprascapular,tibial and peroneal nerves.Sensory nerve conduction examination was performed in bilateral median,ulnar,radial,peroneal and sural nerves.Concentric needle electromyography(nEMG)was tested in bilateral abductor pollicis brevis,extensor digitorum communis,biceps brachii,deltoid,supraspinatus,tibial anterior and soleus muscles.F wave was performed in bilateral median,ulnar and tibial nerves.H reflex was performed in bilateral median and tibial nerves.Sympathetic skin response(S SR)was tested in bilateral extremities.Basic information of patients,such as gender,age,course of the disease,lesion location and the type of stroke were recorded.The motor function of affected extremities was assessed by Brunnstrom grade.The muscular tone of affected flexor carpi radialis and triceps surae were assessed by modified Ashworth scale.Then the changes in electrophysiological test of both sides were compared and the correlation with function outcomes of affected extremities were analyzed.Results:(1)Characteristics of motor nerve conduction:compared with the contralateral side,Compound muscle action potential(CMAP)amplitudes of median,ulnar,radial,axillary,suprascapular,tibial and peroneal nerves decreased significantly(P<0.05),and the conduction velocity of peroneal nerve was slower(P<0.05).But there were no significant differences between distal motor latency of both sides,except peroneal nerve.The rate of abnormal conduction of median,ulnar and radial nerves was higher in patients with a period of 3 to 6 months than other periods.(2)Characteristics of sensory nerve conduction:there were no significant differences in both sides,except decreased sensory nerve action potential(SNAP)amplitude found in the radial,peroneal nerves and lower nerve conductive velocity was found in the ulnar and radial nerve(P<0.05).Further,lower velocity of median sensory nerve conduction on unaffected side was found in nine patients with a longer period of more than 6 months.The rate of abnormal conduction of median,peroneal nerves was higher in patients with a period of 3 to 6 months than other periods.(3)The Brunnstrom grade was correlated positively with the affected/unaffected CMAP ratio of ulnar nerve(r=0.426,P<0.05).(4)needle EMG:Spontaneous activities(SA),including fibrillations and positive sharp waves,were noted in all affected muscles examined.Higher rate of SA was found in the distal muscles,such as abductor pollicis brevis,extensor digitorum communis.Deltoid muscle has high rate SA in patients above 6 months period and high rate SA was also found in soleus muscles in all patients with different periods.Distal and proximal upper extremities appear different SA rate significantly(χ2=14.709,P=0.000).In affected side,muscles without voluntary contraction have higher SA than those can contract(χ2=31.774,P=0.000).(5)H reflex:compared with the contralateral,Hmax/Mmax of median increased.The modified Ashworth scale was correlated positively with the Hmax of median and tibial nerve(P<0.05);(6)F wave:compared with the contralateral,mean amplitudes of median and ulnar increased,conduction velocity of median and ulnar decreased,mean latency of median,ulnar and tibial lengthened significantly(P<0.05).The modified Ashworth score was correlated positively with mean amplitudes of median and tibial nerve(P<0.05);(7)SSR:no matter which side was stimulated,the rate of abnormal changes in SSR was above 67%.And abnormal rate of bilateral upper extremities or bilateral lower extremities was significantly higher than which of unilateral extremity.Abnormal changes of SSR in patients with left hemiplegia were found more commonly than those with right side affected.Conclusions:Motor nerve axonal neuropathy with demyelination and partial sensory nerve demyelination,distal and proximal muscles denervation of affected side and abnormal changes of SSR in both side extremities were the main electrophysiological characteristics in patients with stroke,which were correlated with course of disease and muscle function condition and etc.The amplitudes of motor nerve conduction,H reflex and F wave can provide objective evidences for evaluation of motor function and muscle tone after stroke.