OBJECTIVE: To investigate the electrophysiological effects of focal vibration on the tendon and muscle belly in healthy people. METHODS: The miniaturized focal vibrator consisted of an unbalanced mass rotating offset and wireless controller. The parameters of vibratory stimulation were adjusted on a flat rigid surface as 65 microm at 70 Hz. Two consecutive tests on the different vibration sites were conducted in 10 healthy volunteers (test 1, the Achilles tendon; test 2, the muscle belly on the medial head of the gastrocnemius). The Hoffman (H)-reflex was measured 7 times during each test. The minimal H-reflex latency, maximal amplitude of H-reflex (Hmax), and maximal amplitude of the M-response (Mmax) were acquired. The ratio of Hmax and Mmax (HMR) and the vibratory inhibition index (VII: the ratio of the Hmax after vibration and Hmax before vibration) were calculated. The changes in parameters according to the time and site of stimulation were analyzed using the generalized estimating equation methods. RESULTS: All subjects completed the two tests without serious adverse effects. The minimal H-reflex latency did not show significant changes over time (Wald test: chi2=11.62, p=0.07), and between the two sites (chi2=0.42, p=0.52). The changes in Hmax (chi2=53.74, p<0.01), HMR (chi2=20.49, p<0.01), and VII (chi2=13.16, p=0.02) were significant over time with the adjustment of sites. These parameters were reduced at all time points compared to the baseline, but the decrements reverted instantly after the cessation of stimulation. When adjusted over time, a 1.99-mV decrease in the Hmax (chi2=4.02, p=0.04) and a 9.02% decrease in the VII (chi2=4.54, p=0.03) were observed when the muscle belly was vibrated compared to the tendon. CONCLUSION: The differential electrophysiological effects of focal vibration were verified. The muscle belly may be the more effective site for reducing the H-reflex compared to the tendon. This study provides the neurophysiological basis for a selective and safe rehabilitation program for spasticity management with focal vibration.
Achilles Tendon ; Electrophysiology ; H-Reflex ; Head ; Healthy Volunteers ; Muscle Spasticity ; Reflex, Monosynaptic ; Rehabilitation ; Tendons* ; Vibration

Sciatic nerve injury is a common disease of peripheral nerve in clinic. After nerve injury, there are many dysfunctions in motoneurons and muscles following regeneration. Previous studies mostly investigated the aspects related to the injured nerve, and the effect on the recurrent inhibition (RI) pathway of spine following regeneration was not fully understood. Following reinnervation after temporary sciatic nerve crush, the functional alteration of RI was studied. In adult rats, RI between lateral gastrocnemius-soleus (LG-S) and medial gastrocnemius (MG) motor pools was assessed by conditioning monosynaptic reflexes (MSRs) elicited from the cut dorsal roots and recorded from either the LG-S or MG nerves by antidromic stimulation of the synergist muscle nerve. The following results were obtained. (1) The RI of MSRs in rats was almost lost (<5 weeks) after sciatic nerve crush. Although the RI partially recovered following reinnervation (6 weeks), it remained permanently depressed (up to 14 weeks). (2) Sciatic nerve crush on one side did not affect the contralateral RI. (3) Sciatic nerve crush did not induce any motoneuron loss revealed by immunohistochemistry. Peripheral nerve temporary disconnection causes long term alterations in RI pathway which make up motoneuron's function enhance for the alteration of muscle power and suggests that peripheral nerve injury induces long term plastic changes in the spinal motoneuron circuitry.
Animals ; Long-Term Synaptic Depression ; physiology ; Male ; Motor Neurons ; physiology ; Nerve Crush ; Nerve Regeneration ; physiology ; Neuronal Plasticity ; physiology ; Neurons, Afferent ; physiology ; Rats ; Rats, Wistar ; Reflex, Monosynaptic ; physiology ; Sciatic Nerve ; injuries ; physiopathology ; Spinal Cord ; physiopathology ; Spinal Nerve Roots ; physiopathology

No abstract available.
H-Reflex*

No abstract available.
H-Reflex*

No abstract available.
Electrodes* ; H-Reflex* ; Muscles*

OBJECTIVE: To determine the normal values of flexor carpi radialis (FCR) H-reflex without facilitation, with facilitation and with facilitation & averaging. And to compare the three methods. METHOD: The FCR H-reflex was tested in 60 healthy people. 1) H-reflexes was recorded in the FCR muscle without facilitation. 2) H-reflexes was recorded in the FCR muscle with facilitation and facilitation was carried out by contracting the FCR muscle with 1 kg of weight. 3) FCR H-reflex was tested by repetitive stimulation with facilitation and the multiple responses were averaged. RESULTS: Without facilitation, FCR H-reflexes were elicited only in 24 people out of 60 people and with facilitation, FCR H-reflexes were elicited in all 60 people. The mean latencies and amplitudes of the three methods were measured and normal limits of latency difference and amplitude ratio were calculated. In the FCR H-reflex without facilitation, with facilitation and with facilitation & averaging, the normal limits of latency difference were 1.0 msec, 1.0 msec, 1.1 msec and normal limits of amplitude ration were 0.37, 0.22, 0.57. CONCLUSION: FCR H-reflex with facilitation and with facilitation & averaging might be useful in the clinical diagnosis.
Diagnosis ; H-Reflex* ; Reference Values

The vibratory inhibition index(V.I.I.) of H-reflex, H/M(mean H-reflex amplitude / mean M wave amplitude) and F/M(mean F wave amplitude / mean M wave amplitude) ratios were measured in patients of hyperreflexia with or without spasticity. These data were compared with age-matched control subjects. In comparison to normals, V.I.I. And F/M ratios were increased at statistically significant levels(versus normal : V.I.I. P<0.001, F/M p<0.005) in patient group. And V.I.I.'s were inclined to be correlated with F/M ratios without statistical significance(r=0.27, p=0.21). H /M ratios showed no significant difference between patient and control groups. In these patients, the normal significant correlation between mean F wave amplitude and M wave amplitudes was maintained(p<0.01). F/M ratios were negatively correlated with rnotor nerve conductoion velocity(r= -0.72, p<0.01).These results indicate that V.I.I. And F/M ratios increase in patients with hyperreflexia and/or spasticity. Although mechanisms differ, the data are consistent with a similar physiological responses of H-reflex and F wave to spasticity.
H-Reflex* ; Humans ; Muscle Spasticity* ; Reflex, Abnormal

Since the early discovery of H-reflex by Hoffmann in 1918 there have been a great number of articles in the literature suggesting its clinical used by Magladery in the early 1950. Our experiments about measurement of latent time in H-reflex were performed on 40 normal male adult(composed of medicos and medical officers) and 82 patients(lumbago 40, lumbar disc 42) admitted at CAFGH from January '79. to August '79. The result about normal adult are as follows: 1) The mean value and the standard deviation of the latent time in normal adult(height 171+/-5.14 cm) is 27.74+/-1.86 msec at right leg, 27.77+/-1.64 msec at left one respectively. 2) There may be a linear relationship between latency and the height of normal adult and the difference between right and left is revealed 0.15+/-0.19 msec. We compare the measurementon the 82 patients group with the normal adult experimental groups in addition literatures review.
Adult* ; H-Reflex ; Humans ; Leg ; Male

OBJECTIVE: To find the developing features of H reflex by the gradual increase of stimulation intensity, to evaluate the variability of each H reflex latency, and to verify the consistency of the side-to-side difference of bilateral H reflex latencies in normal population. METHOD: Fifty normal persons (100 limbs) were studied. H reflexes were elicited using standardized technique from Braddom and Johnson. RESULT: H reflex developed in the stimulation intensity at which M response was not evoked in 46 of total 100 limbs. The latency difference between the longest and shortest in each ipsilateral evoked potential was 0~2.1 ms (mean 0.65+/-0.44 ms). In the side-to-side latency difference between the variously evoked H waves, the mean value of maximal one was 1.28+/-0.63 ms (0.4~2.6 ms), and the mean value of the minimal one was 0.24+/-0.35 ms (0~1.5 ms). The mean side-to-side latency difference between the H waves of maximal amplitudes was 0.69+/-0.46 ms (0.1~1.6 ms), and the mean side-to-side difference between the shortest latencies was 0.61+/-0.53 ms (0~2.1 ms). Among these findings the latency difference of the maximal amplitude was observed in 47 cases with 0~1.5 ms, in 3 cases with more than 1.5 ms. CONCLUSION: In diagnosing the S1 radiculopathy with the side-to-side latency difference it will be reasonable to use the latency of maximal amplitude or the shortest latency as diagnostic tool, and reevaluation will be needed with the diagnostic criteria of 1.5 ms latency difference.
Evoked Potentials ; Extremities ; H-Reflex* ; Humans ; Radiculopathy

BACKGROUND AND PURPOSE: Dystonia is not understood and its pathophysiology is uncertain. The fundamental motor abnormality is an abnormality of muscle command signals, in such that the wrong agonists may be activated for too long, there is abnormal co-contraction of agonists and antagonist, and there is excessive and misdirected action of synergists and postural fixators. The reciprocal inhibition of H reflex has been studied for the evaluation of pathophysiology in tonus abnormalities. Lelli et al.(1991) found the similarities in reciprocal inhibition studies between dystonia and Parkinson's disease. He suggested that abnormalities of reciprocal inhibition appear to be a physiologic overlap between two disorders. There is, however, controversy about the results of reciprocal inhibition studies in both disorders. The cutaneous reflex study is another valuable test for the evaluation of the pathophysiology in tonus abnormalities. In an attempt to clarify the pathophysiologic mechanisms of both disorders, we performed cutaneous reflex tests and compared the findings of both disorders with those of the control group. METHODS: 50 normal persons as a control group, 10 patients with dystonia, and 10 patients with Parkinson's disease participated in this study. Cutaneous reflex responses were recorded in the first dorsal interosseous muscle following electrical stimulation of the digital nerves of the index finger. RESULTS: Each mean amplitude of I1 of cutaneous reflex responses in patients with dystonia and in patients with Parkinson's disease is significantly decreased as compared with those of the control group. CONCLUSION: The results from this study lead us to conclude that both dystonia and Parkinson's disease might have abnormalities of inhibitory supraspinal influences on spinal mechanisms.
Dystonia* ; Electric Stimulation ; Fingers ; H-Reflex ; Humans ; Parkinson Disease* ; Reflex*