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Query: UMLS:C0026838 (spasticity)
 6,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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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PMID:The time-course of bilateral changes in the reflex excitability of relaxed triceps surae muscle in human hemiparetic spasticity. 191 13

The purpose of this study was to evaluate and compare the test-retest reliability of isokinetic torque measurements in the involved and uninvolved knee musculature of 20 subjects with spastic hemiparesis. An isokinetic dynamometer was used to measure maximal voluntary knee extension and flexion at 60 degrees and 120 degrees/s. Peak torque (PT) and average peak torque (APT) data were collected from five repetitions on two separate occasions. Average peak torque was defined as the mean of the PT values obtained during each of the five repetitions. Spasticity was measured in the involved knee musculature prior to isokinetic testing using the Ashworth Scale. Pearson Product-Moment Correlation Coefficients and intraclass correlation coefficients (ICCs) were high (greater than or equal to .90) for both knees for PT and APT at both angular velocities. No clinically meaningful differences were found between the Pearson correlation coefficients and the ICCs of the involved versus the uninvolved knee for any testing conditions. We concluded that isokinetic evaluation of torque, as measured by PT and APT in subjects with spastic hemiparesis, can yield reliable results in both extremities.
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PMID:Test-retest reliability of isokinetic knee extension and flexion torque measurements in persons with spastic hemiparesis. 202 95

In the present study a surface-EMG investigation of the rectus femoris muscle was performed in patients with spastic hemiparesis before and after rehabilitation treatment. The EMG activity was detected during 50% of the maximum voluntary contraction by means of FFT automatic analysis; the mean power frequency (MPF) and the time-course of the frequencies of the surface-EMG signals showed significant changes after physiokinesitherapy. In hemiparetic patients a particular distribution of the frequencies of the surface-EMG signals towards the lowest values were observed. These findings could be related to the preferential atrophy of type II fibers which has been demonstrated in morphological studies. Furthermore the surface-EMG analysis after a period of rehabilitation treatment showed some significant modifications of MPF and time-course of the EMG signals. These changes corresponded to an improvement of the spasticity as evaluated by clinical rating-scale. This neurophysiological investigation seem to be a simple and reliable method for better evaluating some effects of the rehabilitation therapy.
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PMID:Surface-EMG analysis of rectus femoris in patients with spastic hemiparesis undergoing rehabilitation treatment. 202 67

As mentioned previously, both MS and PML are demyelinating conditions of the CNS and pose diagnostic difficulties in their differentiation because of similarities in their clinical findings. However, certain features unique to each of these diseases are helpful in clinical diagnosis. MS, unlike PML, is a disease of unknown cause. Polygenetic influences in combination with exposure to an environmental agent and immune-mediated factors may be operative in the pathogenesis of MS. Age of onset peaks in the third to fourth decades with a predominance in women, as contrasted with PML, which peaks in the fifth to sixth decades in most non-AIDS-associated cases with a slight predominance in men. MS is more prevalent in areas farther from the equator: North America, Europe, Australia, and New Zealand. Common initial symptoms seen in MS include bilateral limb weakness (with the legs being affected twice as often as the arms), hyperreflexia, spasticity, optic neuritis, diplopia, incoordination, and paresthesias. (Paresthesias are typically found in the lower limbs in a symmetric pattern, but may follow no obvious anatomic distribution and often do not correspond to the distribution of sensory symptoms. Vibration and position sense are more frequently disturbed than pain and temperature.) Intellectual impairment and mental deterioration are uncommon early in MS, whereas they are a more frequent initial presentation in PML. In addition, the presence of speech impairment and monoparesis or hemiparesis with homonymous hemianopsia is more suggestive of PML. Brain stem involvement is infrequent.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Chronic encephalitis caused by leukoencephalopathy. 222 61

Distinct chronic posttraumatic syndromes, ascribed to neurological deficits of patients suffering severe head injuries and being in prolonged coma, are much less frequently encountered in the literature than acute traumatic syndromes. The major components of the posttraumatic midbrain syndrome, resulting from compressive necrosis or vascular infarction at the midbrain level, are ipsilateral cerebellar signs (the predominant one being intention tremor), contralateral pyramidal signs (the predominant one being a spastic-dystonic hemiparesis), dysarthria, and mild to moderate intellectual impairment. Significant bilateral cerebellar dysfunction following head injury, without pyramidal, extrapyramidal, or pseudobulbar signs, constitutes a posttraumatic cerebellar syndrome. Its most disabling component, namely posttraumatic intention tremor, may be alleviated by thalamotomy. Following severe closed head injury, an infrequently encountered posttraumatic entity of dystonic hemiplegia or hemiparesis, which may be alleviated by thalamotomy, can occur, but does not have a specific neuroanatomical basis. Intention tremors following severe head injuries, rarely associated with hydrocephalus and without other significant cerebellar findings, can develop as a dysfunction of the cerebellofugal outflow system. While chronic posttraumatic syndromes can be complex and difficult to treat, cerebellar stimulation has been utilized ipsilaterally to modulate limb spasticity, and bilateral ventrolateral cryothalamectomies staged 4-6 months apart have been successful in alleviating severe (intractable) intention tremors.
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PMID:Rehabilitative neurosurgery: posttraumatic syndromes. 262 1

Clinical and experimental results are reviewed concerning muscle weakness in patients with hemiparesis after a stroke. The discussion includes the important role that alterations in the physiology of motor units, notably changes in firing rates and muscle fiber atrophy, play in the manifestation of muscle weakness. This role is compared with the lesser role that spasticity (defined as hyperactive stretch reflexes) of the antagonist muscle group appears to play in determining the weakness of agonist muscles. The contribution of other factors that result in mechanical restraint of the agonist by the antagonist (e.g., passive mechanical properties and inappropriate cocontraction) is discussed relative to muscle weakness in patients with hemiparesis.
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PMID:Weakness in patients with hemiparesis. 265 57

Reciprocal inhibition of H reflexes in the forearm flexor muscles was examined in a group of 16 patients with writer's and other occupational cramps. The early disynaptic phase of reciprocal inhibition was normal. However, there was a reduction in the amount of later, presynaptic inhibition, when compared with age-matched normal subjects. Similar findings were seen in 2 patients with symptomatic hemidystonia in whom structural brain lesions were present. However, this reduction in presynaptic inhibition was not specific to patients with dystonia. In a further group of 13 patients with hemiparesis or hemiplegia due to stroke, abnormalities of both early and later phases of reciprocal inhibition were found. The patients with spasticity exhibited less disynaptic inhibition than those with normal tone or flaccid limbs. The changes in the presynaptic phase of reciprocal inhibition did not correlate with the clinical signs of spasticity and increased muscle tone. These results provide objective evidence of a physiological basis for the action or task-specific focal dystonias such as writer's cramp.
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PMID:Reciprocal inhibition between forearm muscles in patients with writer's cramp and other occupational cramps, symptomatic hemidystonia and hemiparesis due to stroke. 273 Oct 27

We report a patient with herpes simplex virus encephalitis who presented with left hemiparesis and progressed to aphasia and generalized spasticity. Computerized axial brain tomography with and without infusion of contrast medium was normal, as were the cerebrospinal fluid findings. However, magnetic resonance imaging scan and brain biopsy, were diagnostic of herpes simplex encephalitis.
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PMID:Magnetic resonance imaging in an unusual presentation of herpes encephalitis. 336 12

The purpose of this retrospective investigation was to determine whether a relationship exists between static strength deficits in the shoulder medial (internal) rotator and elbow flexor muscles and spasticity in these muscles or their antagonists. We reviewed the records of the first 50 stroke patients with hemiparesis who met the entry criteria for the study and who were admitted over a four-month period of time. Static muscle strength was measured by hand-held dynamometry. Spasticity was graded on the Ashworth scale. Kendall's tau correlations were calculated between static muscle strength deficits and spasticity. Static strength deficits of the shoulder medial rotator and elbow flexor muscles were correlated (p less than .01) with the agonist muscles' spasticity, but not with the antagonist muscles' spasticity. Muscle group spasticity and strength deficits, therefore, appear to be covarying manifestations of cerebrovascular accidents. Clinicians, thus, may interpret an agonist muscle's capacity for force production in light of its own tone rather than that of its antagonist.
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PMID:Relationship between static muscle strength deficits and spasticity in stroke patients with hemiparesis. 360 99

I examined the isokinetic knee extension torque (KET) produced by the paretic and nonparetic lower limbs of 27 stroke patients, with hemiparesis, at knee extension velocities (KEVs) of 30 degrees, 60 degrees, 120 degrees, and 180 degrees/sec. The purpose of this study was to determine whether the relative decreases in KET at velocities greater than 30 degrees/sec were different on the two sides. To further investigate this relative decrease, the relationship between the torque at 30 degrees/sec and those at higher speeds also was examined on each side. Relative decreases in KET differed between speeds, but not between sides. Torques at speeds greater than 30 degrees/sec were correlated significantly with the torque at 30 degrees/sec. These findings suggest that patients with hemiparesis and minimal muscle spasticity may have difficulty moving forcefully at higher speeds because they are weak. Therapeutic interventions, therefore, might be most beneficial when they are directed toward helping patients with hemiparesis activate their weak muscles.
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PMID:Relative decreases in knee extension torque with increased knee extension velocities in stroke patients with hemiparesis. 361 90


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