The Characteristic Appearance And Analysis Of H Reflex In Hemiplegic Patients With Post-stroke

Objectives: Limb dysfunction is the main reason of disability in patients after stroke.So it is very important to evaluate the existence and severity of the limb dysfunction in an inchoate and objective way and to give the patients an active prevention and treatment for the extremities'recovery of function. H reflex is a monosynaptic reflex which evaluates the excitability ofαmotor neurons located in the anterior horn of spinal cord and the functional status of sensory and motor fibers in the conductive pathway.H reflex can be shown abnormal in patients with various central nervous system diseases and signs of upper motor neuron lesions.To investigate the valuable application of H reflex in electrophysiological evaluation by study of the relationship between the characteristic appearance of H reflex and functional assessment of affected side in hemiplegic patients with post-stroke.Methods: 31 hemiplegic inpatients with post-stroke in stage of recovery who fulfilled the study entry criteria and came from rehabilitation department of the Second Hospital of Hebei Medical University were in various degrees of limb dysfunction.Their extremities were divided into affected side and unaffected side.The H reflex examination was given to abductor pollicis brevis(APB) dominated by median nerve, abductor digiti minimi(ADM) dominated by ulnar nerve, extensor digitorum communis dominated by radial nerve, gastrocnemius(GS) dominated by tibial nerve, tibialis anterior(TA) dominated by common peroneal nerve of the patients'both sides.At the same time, affected upper extremity was assessed by Modified Ashworth Scale(MAS),affected lower extremity was assessed by Clinic Spasticity Index(CSI).To determine whether H reflex could be easily obtained from all the nerves above.Then comparing the changes in the H reflex latency and ratio of the amplitude of the maximum H reflex to that of the compound action motor potential(Hmax/Mmax) of both sides from which H reflex could be obtained; investigating the differences of the H reflex latency and Hmax/Mmax ratio in affected upper extremities among the different scores of MAS; establishing a correlation between MAS and the H reflex latency or Hmax/Mmax ratio in affected upper extremities; establishing a correlation between CSI and the H reflex latency or Hmax/Mmax ratio in affected lower extremities.Results: H reflex was easily obtained from APB dominated by median nerve, ADM dominated by ulnar nerve, GS dominated by tibial nerve of both sides except extensor digitorum communis dominated by radial nerve and TA dominated by common peroneal nerve.All the data of H reflex obtained from APB,ADM and GS was analysed by SPSS13.0 software. 1 The age,height, H reflex latencies for the median nerve,ulnar nerve and tibial nerve of both sides, Hmax/Mmax ratio values for the ulnar nerve of affected side were fit to normal distribution respectively (P=0.200>0.05). 2 The mean (SD) H reflex latencies for the median nerve,ulnar nerve and tibial nerve of affected sides were 25.89 (3.66)ms, 25.71 (3.26)ms, 30.14 (1.85)ms and that of unaffected sides were 26.60(3.11)ms, 26.44(2.87)ms, 31.95(2.33)ms. 3 The medians of Hmax/Mmax ratio value for the median nerve,ulnar nerve and tibial nerve of affected sides were 0.185,0.217,0.479 and that of unaffected sides were 0.126,0.112,0.192. 4 The differences of H reflex latency between affected sides and unaffected sides for median nerve (P=0.046<0.05),ulnar nerve (P=0.039<0.05) and tibial nerve (P=0.000<0.05) were all statistically significant by using the paired t test, according to theαcriteria of 0.05. The differences of Hmax/Mmax ratio value between affected sides and unaffected sides for median nerve (P=0.017<0.05),ulnar nerve (P=0.001<0.05) and tibial nerve (P=0.000<0.05) were all statistically significant by using the Wilcoxon signed rank test, according to theαcriteria of 0.05. The H reflex latency was reduced and the Hmax/Mmax ratio was increased of affected side comparing with unaffected side for median nerve,ulnar nerve and tibial nerve respectively, and the differences of both sides were statistically significant. 5 By using the Kruskal-Wallis H test , the differences of H reflex latency in affected upper extremities for median nerve (P=0.741>0.05) and ulnar nerve (P=0.404>0.05) were not statistically significant among the different scores of MAS, while the differences of Hmax/Mmax ratio value in affected upper extremities for median nerve (P=0.033<0.05) and ulnar nerve (P=0.018<0.05) were all statistically significant among the different scores of MAS. 6 By using the Spearman rank correlation test, the H reflex latencies for median nerve (coefficient of rank correlation rs=-0.105,P=0.576>0.05) and ulnar nerve (rs=-0.312,P=0.087>0.05), the Hmax/Mmax ratio for median nerve (rs=0.179,P=0.335>0.05) in affected upper extremities were not correlated with MAS respectively, while the Hmax/Mmax ratio for ulnar nerve (rs=0.530,P=0.002<0.05) had a rank correlation with MAS. 7 By using the Spearman rank correlation test, the Hmax/Mmax ratio (rs=0.614, P=0.000<0.05) for the tibial nerve in affected lower extremity had a rank correlation with CSI, while the H reflex latency (rs=-0.325, P=0.074>0.05) did not. The Hmax/Mmax ratio was a better index for the assessment of the excitability of lower motor neurons of affected side in hemiplegic patients with post-stroke.Conclusions: The H reflex examination was given to 31 hemiplegic patients with post-stroke between the affected side and unaffected side. The H reflex was easily obtained from APB dominated by median nerve, ADM dominated by ulnar nerve, GS dominated by tibial nerve of both sides except extensor digitorum communis dominated by radial nerve and TA dominated by common peroneal nerve. It suggests that H reflex is easier to be elicited by stimulating the median nerve, ulnar nerve in upper extremity and the tibial nerve in lower extremity. The H reflex latency was reduced and the Hmax/Mmax ratio was increased of affected side comparing with unaffected side for median nerve, ulnar nerve and tibial nerve respectively, and the differences of both sides were statistically significant. What's more, the Hmax/Mmax ratio for median nerve and ulnar nerve in affected upper extremity was different among various scores of MAS, the Hmax/Mmax ratio for ulnar nerve in affected upper extremity had a rank correlation with MAS, the Hmax/Mmax ratio for tibial nerve in affected lower extremity had a rank correlation with CSI, and all of them were statistically significant. It shows that the Hmax/Mmax ratio is a better index for the assessment of the excitability of lower motor neurons of affected side in hemiplegic patients with post-stroke. In a word, the existence and severity of spasticity of affected side in hemiplegic patients with post-stroke can be evaluated by H reflex which is more objective and quantitative than MAS and CSI. So the H reflex can be an objective electrophysiological index in the clinical assessment of extremities'function in hemiplegic patients , and be applied to the further guidance of rehabilitation therapy ,observation of treatment efficacy.