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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The debilitating loss of function after a stroke has both primary and secondary effects on sensorimotor function. Primary effects include paresis, paralysis, spasticity, and sensory-perceptual dysfunction due to upper motor neuron damage. Secondary effects, contractures and disuse muscle atrophy, are also debilitating. This paper presents theoretical and empirical benefits of aerobic exercise after stroke, issues relevant to measuring peak capacity, exercise training protocols, and the clinical use of aerobic exercise in this patient population. A stroke, and resulting hemiparesis, produces physiological changes in muscle fibres and muscle metabolism during exercise. These changes, along with comorbid cardiovascular disease, must be considered when exercising stroke patients. While few studies have measured peak exercise capacity in hemiparetic populations, it has been consistently observed in these studies that stroke patients have a lower functional capacity than healthy populations. Hemiparetic patients have low peak exercise responses probably due to a reduced number of motor units available for recruitment during dynamic exercise, the reduced oxidative capacity of paretic muscle, and decreased overall endurance. Consequently, traditional methods to predict aerobic capacity are not appropriate for use with stroke patients. Endurance exercise training is increasingly recognised as an important component in rehabilitation. An average improvement in maximal oxygen consumption (VO2max) of 13.3% in stroke patients who participated in a 10-week aerobic exercise training programme has been reported compared with controls. This study underscored the potential benefits of aerobic exercise training in stroke patients. In this paper, advantages and disadvantages of exercise modalities are discussed in relation to stroke patients. Recommendations are presented to maximise physical performance and minimise potential cardiac risks during exercise.
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PMID:Benefits of aerobic exercise after stroke. 872 2

Methods are described for estimating the inertia, viscosity, and stiffness of the lower leg around the knee and of the whole leg around the hip that are applicable even to persons with considerable spasticity. These involve: 1) a "pull" test in which the limb is slowly moved throughout its range of motion while measuring angles (with an electrogoniometer) and torques (with a hand-held dynamometer) to determine passive stiffness and 2) a "pendulum" test in which the limb is moved against gravity and then dropped, while again measuring angles and torques. By limiting the extent of the movement and choosing a direction (flexion or extension) that minimizes reflex responses, the mechanical parameters can be determined accurately and efficiently using computer programs. In the sample of subjects studied (nine with disability related to spinal cord injury, head injury, or stroke, and nine with no neurological disability), the inertia of the lower leg was significantly reduced in the subjects with disability (p < 0.05) as a result of atrophy, but the stiffness and viscosity were within normal limits. The values of inertia were also compared with anthropometric data in the literature. The identification of these passive parameters is particularly important in designing systems for functional electrical stimulation of paralyzed muscles, but the methods may be widely applicable in rehabilitation medicine.
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PMID:Estimating mechanical parameters of leg segments in individuals with and without physical disabilities. 880 Feb 24

Spasticity may occurs as a result of different types of brain injury. The experience with six patients, aged 17-73 years, treated with clonidine for spasticity due to brain injuries of various causes is presented. These cases include a patient with traumatic brain injury, three patients with intracranial haemorrhage, a patient with a right basal ganglia stroke 3 years prior to a left subdural haematoma associated with a fall, and a patient with cerebral palsy. To varying degrees for each patient, clonidine was effective in reducing extremity hypertonicity. A possible mechanism of action is discussed. These case findings suggest clonidine may be useful in the management of spasticity associated with various forms of brain injury, and that formal studies of clonidine for this application appear warranted.
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PMID:Use of clonidine for treatment of spasticity arising from various forms of brain injury: a case series. 881 98

Prevention is of importance when the patient is already suffering from a serious disease, e.g., from arterial obstructive disease causing a stroke or an amputation, from a hip fracture or other diseases that might threaten his independence. Prevention covers a wide field of topics. Most importantly, the patient must recover from his acute disease. It is important to avoid complications which are not specific for the disease but are typical for a bedridden old person (decubital ulcer, dehydration etc.). Prevention also means to avoid recurrence of the same disease as well as complications that frequently occur during the clinical course and may influence the outcome (spasticity in stroke patients, muscular calcification following hip replacement).
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PMID:[Current aspects of secondary and tertiary prevention from the viewpoint of the clinical gerontologist]. 885 Jan 12

Surface electromyography (EMG) and torque were measured from knee flexors and extensors in 12 control subjects (CS) aged 25-59 years (10 female) and bilaterally in 12 stroke subjects (SS) aged 27-75 years (four female) with hemiparesis and mild clinical spasticity. They performed isometric and isokinetic maximal voluntary contractions (MVC) and also isokinetic passive movements at angular velocities from 30 to 300 degrees/s. The time taken to walk 10 m was documented. Greater torque was recorded during passive extension in the paretic legs when compared with both non-paretic and control limbs (p < 0.01). No EMG activity was measured in any subject. Isometric MVC torque of both muscles in the paretic leg was less (p < 0.01) than both the non-paretic and control limbs. The SS generated relatively less torque bilaterally at the lower velocities than CS. Not all SS reached the higher velocities and none of the paretic limbs achieved 300 degrees/s during flexion. Gait speed correlated with maximal paretic knee extension velocity (p < 0.001). The extent of co-contraction during MVCs was generally low or absent and similar in all three groups. These results suggest a mechanical rather than reflex cause for the restraint detected clinically. Low force generation by the paretic agonists appeared to be the major cause of reduced torque, rather than antagonist opposition.
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PMID:Electrical and mechanical output of the knee muscles during isometric and isokinetic activity in stroke and healthy adults. 900 24

Spasticity following stroke reflects a spectrum of clinical problems including increased muscle tone, abnormal limb posture, excessive contraction of antagonist muscles and hyperactive cutaneous and tendon reflexes. The prevalence of stroke-related disability in stroke survivors is high, and spasticity may be a significant component of this. Management strategies include a multidisciplinary team approach utilising a variety of rehabilitation techniques. Although some interventions are well tolerated and fairly standardised, older adults may be particularly sensitive to drug treatment-related adverse effects. This article reviews some of the commonly employed interventions, such as oral medications, and some of the newer techniques, such as intrathecal baclofen infusion and botulinum toxin injections. The optimal management of spasticity following stroke in older adults requires careful goal setting and skilful combination of treatment modalities in order to produce the best outcome.
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PMID:Spasticity after stroke. Epidemiology and optimal treatment. 892 60

It has become increasingly recognized that the major functional deficits following brain damage are largely due to "negative' features such as weakness and loss of dexterity rather than spasticity. A variety of studies suggest that spasticity is a distinct problem and separate from the loss of dexterity, but that it may be implicated in the formation of muscle contracture and even in the recovery of strength. In order to address these issues, we examined the relationship between spasticity, contracture, strength and dexterity in the affected upper limb following stroke. Spasticity was measured both as increased tonic stretch reflexes and increased resistance to passive stretch (hypertonia). Twenty-four patients were recruited non-selectively from three rehabilitation units within 13 months of their stroke. Few patients exhibited increased tonic reflexes but half were found to have muscle contracture, the earliest at 2 months following stroke. Hypertonia was associated with contracture but not with reflex hyperexcitability. Increased tonic stretch reflexes were observed only in a subgroup of those with contracture and where present could usually be elicited only at the end of muscle range. This findings suggests that instead of spasticity causing contracture, contracture may actually potentiate spasticity in some patients. However, the majority of patients with contracture did not have increased tonic stretch reflexes. In addition, we found no relationship between spasticity and either weakness or loss of dexterity. Therefore, while hypertonia remains an important problem following cerebral lesions, it would appear that the amount of attention directed to reflex hyperexcitability associated with spasticity is out of proportion with its effects. Consequently, hypertonia needs to be clearly distinguished from reflex hyperexcitability in patients with spasticity.
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PMID:Spasticity and muscle contracture following stroke. 893 94

The use of a functional neuromuscular stimulation (FNS) device can have therapeutic effects that persist when the device is not in use. Clinicians have reported changes in both voluntary and electrically assisted neuromuscular function and improvements in the condition of soft tissue. Motor recovery has been observed in people with incomplete spinal cord injury, stroke, or traumatic brain injury after the use of motor prostheses. Improvement in voluntary dorsiflexion and overall gait pattern has been reported both in the short term (several hours) and permanently. Electrical stimulation of skin over flexor muscles in the upper limb produced substantial reductions for up to 1 h in the severity of spasticity in brain-injured subjects, as measured by the change in torque generation during ramp-and-hold muscle stretch. There was typically an aggravation of the severity of spasticity when surface stimulation reached intensities sufficient to also excite muscle. Animals were trained to alter the size of the H-reflex to obtain a reward. The plasticity that underlies this operantly conditioned H-reflex change includes changes in the spinal cord itself. Comparable changes appear to occur with acquisition of certain motor skills. Current studies are exploring such changes in humans and animals with spinal cord injuries with the goal of using conditioning methods to assess function after injury and to promote and guide recovery of function. A better understanding of the mechanisms of neural plasticity, achieved through human and animal studies, may help us to design and implement FNS systems that have the potential to produce beneficial changes in the subject's central nervous systems.
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PMID:Therapeutic neural effects of electrical stimulation. 897 48

We studied the effects of electrical stimulation of the skin on upper extremity spasticity in nine hemiparetic stroke subjects. The effects were quantified by comparing reflex torque responses elicited during ramp and hold angular perturbations of the elbow recorded before and after low-intensity skin stimulation. Electrical stimulation was applied to skin over the biceps muscle for a period of ten minutes at a 20 Hz frequency, pulse duration 0.1 ms, with an intensity level below motor threshold but above sensory threshold. In seven of the nine subjects, stimulation of skin over spastic muscle reduced peak torque responses in both flexors and extensors for at least 30 min. In these seven subjects there were significant increases in mean threshold angle for the onset of reflex torque so that a greater angular rotation was required to initiate the stretch reflex response. This shift occurred without change in reflex impedance. The origins of these long-term changes in reflex torque are unclear, but may reflect synaptic plasticity of spinal circuitry outside the stretch reflex loop.
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PMID:Long-lasting reductions of spasticity induced by skin electrical stimulation. 897 49

This study sought to test the hypothesis that injections of botulinum toxin type A (BTX-A) at the mid belly of the gastrocnemius muscle in spastic hemiplegic adults produce superior clinical results to proximal injections directed toward the muscular origin. We designed a randomized, double-blind, placebo-controlled intervention study at a university tertiary care setting. Seventeen subjects with chronic spastic hemiplegic gait were enrolled from a volunteer community sample; time range from acute neurologic insult was 0.75 to 31 yr; age range was 19 to 71 yr; gender consisted of 11 men and 4 women; diagnoses were 12 patients with stroke, 2 with traumatic brain injuries, and 1 with a brain tumor. Two subjects were withdrawn from the study because of (1) acute vascular occlusion before intervention and (2) noncompliance with follow-up visits. After baseline measurements, subjects were injected with 50 units of BTX-A (volume, 0.5 cc) into the medial or lateral gastrocnemius: (1) proximally at one site near the muscular origin; (2) distally at three sites along the mid belly. We measured outcome using the Fugl-Meyer score, Ashworth scale, ankle range of motion, and a timed 50-ft fastest walk. No outcome measures showed a significant effect attributable to site of injections. Confounding variables included physical therapy and varying duration of illness in the study cohort. We conclude that the results failed to support the hypothesis that BTX-A injections at the mid belly of the gastrocnemius produced superior functional improvements to injections located near the muscular origin using localization techniques described. Additional research comparing more precise localization methods for BTX-A injections might further establish the importance of electromyographic guidance using BTX-A in management of spasticity.
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PMID:Comparison of two injection techniques using botulinum toxin in spastic hemiplegia. 898 11


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