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PubMedDate not supplied

Artificial feedforward as preparatory motor control in postictal hemiparesis.

One of the most important disturbances in spastic hemiparesis is the lack of reciprocal inhibition and the insufficient and inadequate preparatory programming of this inhibition. In 40 patients with postical hemiparesis some preparatory procedures foregoing the volitional movement attempt were assumed. The movement was extension of the wrist and the intended reciprocal inhibition was that in the wrist flexors. The procedures were extensor muscle vibration or electrostimulation which produce contraction of the wrist extensors and reciprocal inhibition in the wrist flexors. A conditioning has been attempted of these effects achieved at spinal level to the existing ipsilateral and spared contralateral cortical influences during a volitional extension of the wrist. In this way an artificial feedforward have been created, with favourable results in motor reeducation of wrist movements.

Cerebrovascular Disorders↗

PubMed1976

Spastic paresis after 6-aminonicotinamide: metabolic disorders in the spinal cord and electromyographically recorded changes in the hind limbs of rats.

In rats the application of 10 mg/kg 6-amino-nicotinamide (6-AN) leads to an accumulation of 6-phosphogluconate, by inhibition of 6-phosphogluconate dehydrogenase in the pentose phosphate pathway, in the cells of the spinal cord. The accumulation reaches its maximum after 18-24 h. It seems that there exists a relationship between the accumulation of 6-phosphogluconate and the lesion of the neuroglia, which is found in electron microscopic studies. Symptoms of a spastic paresis only develop later when the spinal interneurones are destroyed as a consequence of the lesion of the neuroglia. The accumulation of 6-phosphogluconate almost exceeds the 400 fold of the norm. No considerable differences are found between the effects of a dose of 35 mg 6-AN/kg and one of 10 mg 6-AN/kg. Free gluconate is identified enzymically in the cells of the spinal cords of the rats treated with 6-AN. The compound is very probably formed by dephosphorylation and diffuses into the blood. 6-Phosphogluconate is an inhibitor of the phosphoglucose isomerase. Its accumulation shifts the equilibrium towards glucose 6-phosphate. The lactate concentration decreases as compared with the untreated controls. Muscular action potentials are recorded extracellularly with a concentric needle electrode from the musculus gastrocnemius of rats treated with 6-AN. First activations of the electromyograms are found 48 h after the application of 10 mg 6-AN/kg. The electrical activities increase during the time in which a progressive destruction of the interneurones occurs. The electromyogram displays a permanent state of excitation with high amplitudes and an increased frequency. The continuity and intensity of the increased activity recorded by the electromyograph is the most important pathological finding. p-Chlorophenyl-GABA and, still more so, chlorpromazine cause temporary reduction of the excitation processes and an electromyogram nearly at rest. Under the same conditions, haloperidol is only slightly effective. The symptoms developed by the chemical destruction of the interneurones of the spinal cord, with rigidity and spasticity of the hind limbs, are suitable for testing antispastic drugs.

6-Aminonicotinamide↗

PubMed2003

Quantitative evaluation of reflex and voluntary activity in children with spasticity.

OBJECTIVE: To determine whether increased reflexes are related to functional impairment in children with spasticity. DESIGN: Descriptive measurement study. SETTING: Rehabilitation department in Poland. PARTICIPANTS: Sixteen able-bodied children and 29 children with spasticity. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Measurement of modulation function of knee tendon reflexes by isometric knee extension, maximum isometric knee flexion, and extension torques, and scoring of ambulation in patients. RESULTS: In able-bodied children, the reflex modulation function increased with voluntary knee extension, reached maximum at 5% to 20% of voluntary extension, and then decreased. The reflex modulation function in patients fell into 2 major categories. In the majority of affected limbs, the modulation function was inverse, with maximum reflex response at relaxation, and decreased with an increase of voluntary extension. In the remaining limbs, the shape of the reflex modulation function was normal, although other parameters changed. Isometric torques decreased more in flexion (65%) than in extension (39%). A torque decrease was a result of cocontraction more often during knee flexion (65%) than in knee extension (24%). The larger the reflexes, the more flexion torque decreased and ambulation deteriorated. This pattern occurred in patients with inverse modulation function but not in those with normal modulation function. The reciprocal inhibition from knee flexors to extensors could be affected in patients with inverse modulation function and cocontraction during flexion, whereas other mechanisms occurred in other patients. CONCLUSIONS: The experimental design has potential as a quantitative measure of abnormal control in children with spasticity and can lead to more precise treatment selection criteria.

Adolescent↗

PubMed1993

H-reflex changes during contractions of the ankle extensors in spastic patients.

Soleus H-reflexes during tonic contractions and isometric ramp contractions of the ankle extensors in spastic and healthy subjects were measured. During the tonic contractions, the H-reflex increased with the contraction level. The increase was highest in the patients (p < 0.001). The facilitation of the H-reflex during a ramp contraction is due to a static component resulting from the increased excitation level and a dynamic component resulting from the modulation of the H-reflex. The dynamic H-reflex facilitation during the ramp contraction was decreased in the patients (p < 0.05). The findings suggest that there is a decreased H-reflex control in spastic patients and this could be explained by a decreased presynaptic inhibition or by postsynaptic changes.

Adult↗

PubMed1990

Microsurgical ablative procedures in the peripheral nerves and dorsal root entry zone for relief of focal spasticity in the limbs.

When spasticity is harmful and localized in the limb(s), ablative procedures in the peripheral nerves or the dorsal root entry zone (DREZ) can be useful. The authors report on the long-term results of (1) selective tibial neurotomy in a series of 62 spastic feet, and (2) microsurgical DREZ-tomy in a series of 69 patients affected with hyperspasticity in the entire upper or lower limb(s).

Follow-Up Studies↗

PubMed1994

Inclusion of the S2 dorsal rootlets in functional posterior rhizotomy for spasticity in children with cerebral palsy.

Many neurosurgeons have made a practice of sectioning the S2 dorsal roots during selective posterior rhizotomy for the treatment of spasticity in children with cerebral palsy, but the efficacy of this treatment has not previously been proven. S2 afferents are involved in reflex arcs of the plantar flexors (PFs), so that S2 lesioning should in theory reduce PF spasticity. To test this assumption, we determined the frequency of postoperative residual spasticity in the PFs when S2 lesioning was or was not performed. We assessed 85 children for whom 6-month follow-up was available. Functional rhizotomy from L2-S1 was performed on 13 of them (26 legs with PF spasticity) and from L2-S2 on 72 (141 legs with PF spasticity). Rootlets were lesioned if there was an abnormal response to intraoperative electrical stimulation. In 20 patients, lesioning of the S2 rootlets was assisted by the "pudendal neurogram," a technique previously shown to prevent bladder dysfunction during sectioning of the sacral roots. When S2 roots were excluded from the lesioning process, residual PF spasticity was detected in 35% of the legs that had it preoperatively, leaving 5 (38%) of 13 children with functionally impairing spasticity. When S2 roots were included, 6% of legs that had PF spasticity retained it postoperatively (P < 0.001), leaving 8 (11%) of 72 patients with functionally limiting spasticity (P < 0.05). Thus, the addition of the S2 roots to the procedure resulted in an 81% reduction in the number of legs with residual PF spasticity and a 71% reduction in the number of patients with residual PF spasticity.(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗

PubMedDate not supplied

Spasticity measurement in stroke: a pilot study.

The ability to objectively measure spasticity, related to cerebral stroke, is important in the rehabilitation therapies since many therapeutic modalities have been developed over the years to reduce spasticity. The unproven clinical expectation is that function would be improved were spasticity to be reduced. Unfortunately, the ability to measure spasticity to conduct efficacy studies of spasticity-reducing therapies is not possible. This relates to the multi-variable nature of the spastic syndrome with the result that no clinical measurement technique has been proven to be sensitive, valid and reliable. Therefore, it is important to develop a research-oriented spasticity measurement system to meet this need. We describe the current development of such a system. Details of our pilot study of a reflex excitability technique, designed to measure certain components of cerebral spasticity, are presented. The technique combined biomechanical and electrophysiological measures to investigate a homogenous stroke sample (n = 6); it incorporated the H-reflex in soleus, during passive ankle movements, as a measure of faulty neural inhibition. This component significantly (p < .05) differentiated the stroke sample from a matched, healthy control group (n = 6). Evocation of a cutaneous reflex in soleus was a condition that was problematic and it had to be dropped from the protocol. Joint stiffness, which is thought to affect measures of spasticity during passive movement, did not contaminate the measures. Further research in this direction is required to delineate and measure other neural components of spasticity while taking into account related non-neural variables. The final objective in this line of research is to develop a valid, reliable and sensitive spasticity measurement system that could be used to judge the efficacy of physical neurorehabilitation treatments currently employed to reduce spasticity following stroke.

Aged↗

PubMed2002

Effect of intrathecal clonidine on group I and group II oligosynaptic excitation in paraplegics.

We investigated the possibility that a change in transmission in group II pathways contributes to the spasticity of patients with spinal lesions. Thirteen patients were tested by measuring the quadriceps stretch reflex (Ashworth scale), the threshold of the quadriceps H reflex, and the oligosynaptic facilitation of the quadriceps H reflex elicited by volleys to groups I and II afferents in the common peroneal nerve (CPN). All these tests were performed before and after intrathecal injection of clonidine (60 microg). Early group I CPN-induced excitations occurred in 13 patients, and late group II CPN-induced excitations in 12. Both facilitations were, on average, significantly greater than those reported for normal subjects, but these increases were not correlated with the clinically assessed spasticity. Clonidine caused a constant, prolonged and dramatic decrease in spasticity, but did not alter the threshold of the quadriceps H reflex. CPN-induced group I and group II non-monosynaptic excitations of quadriceps motoneurones were significantly decreased, although they did not return to normal values. These results provide a further indication that group II pathways gives rise to the heteronymous late CPN-induced excitation. The pathophysiological role of a change in transmission in group II pathways in spasticity is discussed.

Adrenergic alpha-Agonists↗

PubMed2003

Clinical utility of the Duncan-Ely test for rectus femoris dysfunction during the swing phase of gait.

The Ely Test (or Duncan-Ely test) has been accepted as a clinical tool to assess rectus femoris spasticity by passively flexing the knee rapidly while the patient lies prone in a relaxed state. In this retrospective review, patients' dynamic knee range of motion (ROM) during gait and an electromyogram (EMG) were compared with the results of the Ely test. Data for 70 patients (44 males, 26 females; 104 limbs) were included. Mean age of patients was 13 years, SD 9 years, range 4 years 5 months to 54 years. All patients were diagnosed with cerebral palsy (spastic diplegia, n = 42; spastic quadriplegia, n = 15, and hemiplegia, n = 13). All patients were ambulatory (50 independent, 20 with assistive devices). A standard matrix was used to calculate sensitivity and specificity of the Ely test as well as its positive and negative predictive value. For the gait variables examined (decreased dynamic knee ROM, timing of peak knee flexion, and abnormal EMG in swing) the sensitivity of the Ely test ranged from 56 to 59% and the specificity ranged from 64 to 85%. For the same variables the positive predictive value ranged from 91 to 98% and the negative predictive value ranged from 4 to 19%. The Ely test was shown to have a good positive predictive value (i.e. the certainty about the presence of rectus spasticity in patients with a positive Ely test result) for rectus femoris dysfunction during gait.

Adolescent↗

PubMed2003

Temporospatial parameters of gait after obturator neurolysis in patients with spasticity.

OBJECTIVE: The management of spasticity should be implemented with the most appropriate pharmacologic agents. Ideally, these agents should provide functional improvement with minimal adverse effects. The aim of this study was to evaluate the width of the base of support and the velocity of gait before and after obturator nerve block. Blocks were performed with aqueous phenol solution in patients with unilateral hip adductor muscle overactivity that resulted in scissoring gait. The goal was to analyze functional improvement and quantify outcomes and to attempt to document adverse effects. DESIGN: This retrospective study analyzed data from 24 patients' files. Inclusion criteria included subjects whose main functional complaint was an adducted gait pattern. All subjects were able to consent for and to undergo unilateral obturator neurolysis with 7% phenol solution. Temporospatial parameters of gait were obtained using the Gait Mat II before and after obturator nerve injection. RESULTS: The analysis showed no statistical change in the walking velocity or step length. However, the width of the base of support was significantly increased after injection. No postblock complications were reported. CONCLUSION: Obturator neurolysis with 7% phenol solutions is an effective procedure to decrease hip adductor muscle overactivity without reported complications. In the studied population, improvement was found in the width of the base of support without immediate change in walking velocity or step length.

Adult↗

PubMed2000

Baclofen increases the soleus stretch reflex threshold in the early swing phase during walking in spastic multiple sclerosis patients.

The effect of baclofen on walking performance was examined in nine spastic multiple sclerosis patients. In addition, nine healthy subjects were tested as controls. The modulation of the short latency soleus stretch reflex was closer to normal with baclofen compared to the recordings without baclofen, the modulation index being 74% (range: 60 - 100) with baclofen and 62% (range: 20 - 100) without baclofen, P=0.03. In healthy subjects the modulation index was 100% (range: 52 - 100). In the early swing phase the threshold of the soleus stretch reflex was significantly higher during baclofen medication being 139 deg/s (range: 63 - 302) compared with 93 deg/s (range: 37 - 187) without baclofen, P=0.004. The relation between the stretch velocity (input) and the amplitude of the stretch reflex (output) in early swing phase was unchanged being 0. 27 microVs/deg (range: 0.1 - 1.51) in patients with baclofen and 0. 24 microVs/deg (range: 0.08 - 0.79) without baclofen, P=0.25. Baclofen induced no change in input - output properties of the stretch reflex during walking compared with findings in a sitting position at matched EMG activity. There was a significant correlation between clinical spasticity score and stretch reflex threshold in the early swing phase (rho=-0.61, P=0.04) and between clinical spasticity score and the slope of the best linear fit in the early swing phase (rho=0.72, P=0.009).

Adult↗

PubMed2003

Pathophysiology of pediatric movement disorders.

Pediatric movement disorders constitute a relatively small cluster of symptoms that can be associated with many different underlying diseases. To provide effective treatment, it is essential to understand the relationship between etiology and clinical expression. This article reviews the recent literature on several common pediatric movement disorders, including spasticity, dystonia, chorea, myoclonus, bradykinesia, and tics, and it discusses current models of physiology that may help link the cellular pathology of specific diseases to the expression of clinical symptoms.

Ataxia↗

PubMed1998

Intrathecal baclofen infusion and subsequent orthopedic surgery in patients with spastic cerebral palsy.

UNLABELLED: Intrathecal baclofen infusion (IBI) is an effective treatment for spasticity secondary to cerebral palsy (CP). OBJECT: To assess the need for orthopedic surgery of the lower extremities in such cases, the authors retrospectively reviewed the outcome in 48 patients with spastic CP who were treated with IBI. METHODS: Pumps were placed in 40 patients (84%) suffering from spastic quadriplegia and eight patients (16%) with spastic diplegia. The patients' ages ranged from 5 to 43 years (mean 15 years). The mean follow-up period was 53 months (range 24-94 months). The mean baclofen dosage was 306 microg/day (range 25-1350 microg/day). At the time of pump placement, subsequent orthopedic surgery was planned in 28 patients (58%); however, only 10 (21%) underwent surgery after IBI therapy. In all 10 cases, the surgical procedure was planned at the time of initial evaluation for IBI therapy. In the remaining 18 patients, who did not subsequently undergo their planned orthopedic operation, it was believed that their lower-extremity spasticity had improved to the degree that intervention was no longer indicated. In addition, although six patients had undergone multiple orthopedic operations before their spasticity was treated, no patient required more than one operation after IBI treatment for spasticity. CONCLUSIONS: The authors conclude that IBI for treatment of spastic CP reduces the need for subsequent orthopedic surgery for the effects of lower-extremity spasticity. In patients with spastic CP and lower-extremity contractures, spasticity should be treated before orthopedic procedures are performed.

Adolescent↗

PubMedDate not supplied

Partial NADH dehydrogenase defect presenting as spastic cerebral palsy.

Mitochondrial myopathies are heterogeneous disorders. They may present at any age with a variable clinical course. We report a 6-year-old boy presenting as spastic cerebral palsy for 4 years, then athetotic movements and loss of milestones. He was eventually found to have NADH dehydrogenase deficiency.

Athetosis↗

PubMed1987

Results of fractional lengthening of the finger flexors in adults with upper extremity spasticity.

Flexor spasticity is common in the upper extremity after insult to the central nervous system. This leads to decreased function and hygiene problems as a result of the inability to extend the fingers. The results of fractional lengthening of the finger flexors of 27 patients with upper extremity flexor spasticity of the finger flexors were examined. Patients were divided preoperatively into those with potentially functional hands and those who were nonfunctional based on the presence of motor control and hand sensibility. Follow-up time averaged 33 months. Postoperatively, all five nonfunctional hands, which lacked any motor control, improved in posture, and the hygiene problems resolved. Twenty of the 22 patients with potentially functional hands (91%) improved their spastic hand function score, a mean of 3.7 points. Two patients (9%) decreased their spastic hand function score as a result of overlengthening of the finger flexors, with loss of grip strength.

Adult↗

PubMed1980

Intramuscular alcohol as an aid in management of spastic cerebral palsy.

The use of intramuscular alcohol in treating cerebral-palsied children has led to reduced spasticity for varying periods of time, although the periods diminish with each subsequent injection. During the period of reduced spasticity there is an opportunity for therapists and orthopaedic surgeons to determine whether corrective surgery is indicated. The injections have produced no adverse effects.

Adolescent↗

PubMed1996

Electromyographic and positional changes in the elbows of spastic hemiparetic patients during walking.

The displacement of the paretic elbow of hemiparetic patients into flexion during walking is an acknowledged associated reaction characteristic of upper limb spasticity. The main purpose of this study was to examine the step-dependent pattern and magnitude of the angular and electromyographic changes which take place during this flexion movement. Steps-related changes in elbow angle were measured on the paretic side of 14 hemiparetic patients during walking with a 4-point cane. The EMG activity of the ipsilateral biceps and triceps brachii muscles was concomitantly recorded. The activity of the brachioradialis muscle in 8 patients was monitored as well. In another trial, the angular and electromyographic activities were measured bilaterally in 7 patients during free walking. Flexion movement on the paretic side was characterized by a steep increase in flexion occurring during the first 4 steps, followed by a more gradual rise with successive stepping. Neither the electromyographic activity of the elbow flexor nor that of the extensor muscles was related to that flexion movement. The excursion into flexion on the non-paretic side was smaller than on the paretic side and incorporated flexion-extension fluctuations. The associated reaction at the paretic elbow during walking is a postural response which is triggered by the balance perturbation in the gait activity. It starts with a steep rise in flexion which seems to be reflexive in nature. The preservation of elbow flexion during walking may be an expression of stiffening of the elbow flexor muscles fibers.

Adult↗

PubMed2004

Neuromuscular modeling of spasticity in cerebral palsy.

Data from the pendulum knee test has been used to develop two active models that use external torques to closely match the experimental knee trajectories of subjects with spasticity due to cerebral palsy. These data were collected from three subjects who are identical triplets; two of whom have clinically measurable spasticity. A passive model that accurately describes the knee trajectory of the nonspastic subject serves as the passive plant for two active models. One of these models allows direct application of external torques, and the second provides additional torque as the result of velocity feedback. Both active models and the passive model use separate parameters of stiffness and damping for the agonist and antagonist muscles.

Cerebral Palsy↗