Electrical stimulation of antagonist muscles in the relaxation of spasticity.
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PURPOSE: Cooling muscles might produce a temporary reduction of spasticity. This study investigated muscle co-ordination in spasticity under the influence of cooling. METHODS: A repetitive movement (RM-) test of the ankle was used, while measuring the angle and surface-electromyography (EMG) of the m. tibialis anterior and m. triceps surae. Ensemble averaging provided quantified measures of muscle activation. Sixteen patients with spasticity in their lower extremity due to stroke or spinal cord injury participated in the study. Physical examination and the RM-test was done before and after cooling the m. triceps surae for 20 minutes by coldpacks. RESULTS: The results show that Achilles hyperreflexia and clonus were abolished in all, and all but one patient, respectively. The EMG of the m. triceps surae, acting as a prime mover, was increased (p = 0.028). However, this improved muscle co-ordination resulted in just a slightly increased active range of motion (less than 2 degrees at p = 0.049). CONCLUSION: Apparently, the increase in excitability of the alpha motoneuron pool in voluntary movements of patients with spasticity is not followed by an improvement in the ability to move.
Surface electromyographic "EMG" activity in biceps brachii (agonist muscle) and triceps brachii (antagonist muscle) as well as the discharge behaviour of motor units "MUs" (needle recording) in biceps brachii muscle were recorded during slow (0.33 Hz) and fast (0.66 Hz) voluntary elbow flexion movements (auditory matching task) in fifty patients with spastic hemiplegia. In the spastic limbs, a long lasting, small amplitude tonic co-contraction of antagonist muscles was seen during slow flexions (SF) in 29 cases. This effect was strongest during the fast elbow flexion movements (FF). In 33 patients a triphasic pattern of muscle activation was observed on the unaffected side but not on the spastic side. The amplitude of the agonist surface EMG was significantly reduced and the amplitudes of the MU potentials recruited during maximal effort were generally smaller on the spastic side compared to the unaffected side. The agonist-antagonist activation pattern was analysed with respect to three clinically identifiable functional recovery stages of voluntary movements in the spastic limbs, namely synergistic, isolated and useful movements. The MU amplitudes and the amplitude of the surface EMG activity in the agonist muscle recorded during FF movements became significantly larger whereas the amplitude of the antagonist tonic activity became smaller with increasing functional recovery of the limb. It is concluded that impaired recruitment of type II motor units in the agonist muscles and the inability to selectively activate the agonist muscle contribute to the deficit in motor performance in spastic paresis.
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Static and dynamic components of the stretch reflex were studied in elbow flexors of 13 hemiparetic brain-injured individuals. Constant-velocity joint rotations were applied to the elbow, and the resulting stretch reflex torque and electromyographic responses were recorded in the biceps brachii and brachioradialis muscles. Ten elbow extension velocities between 6 and 150 deg s(-1) were applied in random order. The resulting reflex torque response was plotted as a function of elbow angle and fitted with a mathematical model designed to depict elbow flexor activation. We found that four of the six model parameters were essentially independent of test velocity. Conversely, 73% (19/26) of cases involving the other two model parameters were dependent on velocity of joint extension (p<0.05). We conclude from these results that four of the model parameters reflect the static reflex response while the two remaining velocity-dependent parameters reflect the dynamic reflex response. To describe overall velocity dependence of stretch reflexes in spastic elbow muscles, the two dynamic reflex parameters were fitted to a fractional exponential function of velocity, similar to a model previously used to describe spindle firing rate in the cat hindlimb. We found that the mean velocity exponent of the dynamic reflex parameters was 0.24 + 0.17 (s.d.) (N = 13), a value similar to that for muscle spindle velocity sensitivity in reduced animal preparations. We conclude that both static and dynamic reflex sensitivities can be measured by examining different aspects of the torque/angle relation associated with the reflex response to a large-amplitude ramp stretch of the elbow.
Mechanism of coronary spasm was examined regarding endothelium-related relaxation and contraction produced by smooth muscle cells of spastic vessels isolated from Göttingen miniature pigs. In these pigs, coronary artery spasm was documented angiographically in vivo three months after endothelial denudation, and spastic and control segments of the coronary artery were suspended in organ chambers at their optimal length for generating tension. Applications of KCl (118 mM), acetylcholine(10(-9) to 10(-4) M), and PGF2 alpha (10(-8) to 3 X 10(-5) M) produced similar tension, at the respective doses, in both the spastic and control coronary arteries. During increasing concentrations of histamine (10(-8) to 3 X 10(-4) M; n = 14) and serotonin (10(-9) to 10(-5) M; n = 13), the maximum tension of the spastic vessel was 136 +/- 6 and 97 +/- 4%, respectively, of the tension produced by 118 mM KCl. That is significantly larger than seen in the control vessels: 98 +/- 4 and 74 +/- 4%, respectively. The ED50 to histamine and serotonin was also significantly less in the spastic vessels. After mechanical removal of the endothelium, the tension generated during the cumulative administration of histamine (n = 8) but not serotonin (n = 8) was larger in the spastic than the control vessels, thereby suggesting the presence of augmented responses of the smooth muscle to histamine in the spastic vessels. The increase in maximum tension after mechanical denudation was greater in the control than the spastic vessels in cases of histamine and serotonin.(ABSTRACT TRUNCATED AT 250 WORDS)
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Within the complex medical rehabilitation of patients with apoplexia physiotherapy occupies an important position. The individual functional kinesitherapy on neurophysiological basis shall begin immediately after the acute pathological process. The electrotherapy may be used in the laxly as well as spastically paralysed muscle. In the early phase by this means the gradually developing spasticity and the muscle atrophies are diminished. The cryotherapy reduces the tonus of the spastic muscles and provides better prerequisites for the kinesitherapy. The work therapy has the task to restore the fine motoricity of the diseased hand and to make the patient again independent in the activities of daily life.
Short, rapid dorsiflexion of the normal human ankle induces a single, synchronised reflex EMG response in the initially relaxed triceps surae muscle (TS). In subjects in whom hemiparesis is present as a result of a unilateral ischaemic cerebral lesion, a reflex EMG response can be elicited on either side with timing identical to that of the normal response. The magnitude of the response in hemiparetic subjects, however, differs from the normal on both the side contralateral and that ipsilateral to the causative lesion. Furthermore, the magnitude of this response varies over the time-course of spasticity. Contralaterally to the lesion, a gradual increase in the magnitude of the response to imposed displacement occurs. One year after stroke, the response has reached a level significantly larger than normal. Changes in the magnitude of the contralateral Achilles tendon jerk reflex EMG are apparent earlier than changes in the response to imposed displacement, with exaggerated tendon jerks already being apparent between 1 and 3 months after stroke. On the side ipsilateral to the lesion, a profound depression of the response to imposed displacement is visible as early as a month after stroke. This depression diminishes over the 1st year, but the response has not even then returned to normal values. These changes are not reflected in the ipsilateral tendon jerk response, which remains normal throughout this period.(ABSTRACT TRUNCATED AT 250 WORDS)
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OBJECTIVE: To evaluate the effectiveness of alcohol neurolysis of tibial nerve motor branches to the gastrocnemius muscle for the treatment of ankle plantarflexor spasticity in patients with hemiplegic stroke. DESIGN: Case series. SETTING: Inpatient and outpatient clinics in the rehabilitation department of a university hospital. PARTICIPANTS: Twenty-two patients with hemiplegic stroke (mean age, 48y). INTERVENTIONS: Motor branch block (MBB) of the tibial nerve to the gastrocnemius muscle with 50% ethyl alcohol in cases of spastic ankle. MAIN OUTCOME MEASURES: The severity of spasticity was assessed using the Modified Ashworth Scale (MAS) score of ankle plantarflexor, clonus score of the ankle, and the passive range of motion (PROM) of ankle dorsiflexion. RESULTS: The MAS score was reduced in 17 (77%) of 22 patients during the 6-month follow-up, and spasticity reappeared at the level of the pre-MBB state in 5 patients (23%). The mean values of all parameters were significantly improved. The changes of mean values from the pre-MBB to the 6-month post-MBB stage were as follows: MAS score, 3.3+/-0.7 versus 1.7+/-1.1; clonus score, 1.6+/-0.7 versus 0.4+/-0.8; and PROM, 17.1 degrees +/-13.0 degrees versus 28.6 degrees +/-4.7 degrees. No serious complications were observed during the 6-month follow-up period. CONCLUSIONS: MBB of the tibial nerve to the gastrocnemius muscle is an effective and safe procedure for relieving localized spasticity of the ankle plantarflexors.
This study evaluated the effects of manual stretch of extrinsic finger flexor muscles on finger extension movement control and force control in 16 spastic hemiparetic subjects. These subjects were randomly divided into a control group and an experimental group. A group of able-bodied subjects also participated. A joint-movement tracking test (JMTT) quantified control of active finger extension movement at the metacarpophalangeal joint of the index finger within the available range of active movement, and a force tracking test (FTT) quantified control of isometric finger extension force at the same joint within the subject's available force range. Electromyographic activity was monitored in the extensor digitorum and flexor digitorum superficialis muscles during both tracking tests. Manual stretch was applied to the extrinsic finger flexor muscles of the experimental group between the pretest and posttest tracking tests. The JMTT performances of both control (p less than .025) and experimental (p less than .05) groups were significantly subnormal on the pretest as were FTT performances of controls (p less than .01) and study subjects (p less than .03). The JMTT improvement on posttest was significantly greater (p less than .05) in subjects than in controls. However, the change in FTT performance was not significantly different between the two groups. Manual stretch treatment, properly applied to extrinsic finger flexor muscles, is an effective method of temporarily improving the control of finger extension movement in spastic hemiparetic subjects.
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