Air-splint pressure effect on soleus muscle alpha motoneuron reflex excitability in subjects with spinal cord injury

Casting for the Person with Spasticity

Casting is a fairly well-established option for the reduction of contractures due to spasticity, as well as a method for reducing tone. Some research suggests that casting is more effective than traditional therapy techniques in reducing contracture and is inconsistently better at decreasing hypertonicity. Traumatic brain injury and cerebral palsy are the most common diagnostic groups that are identified in the literature as benefiting from casting, but severe spasticity resulting from a stroke may also be positively affected by this technique. Several forms of casting are mentioned in the literature, including serial casting, inhibitive casting, drop-out casts, and bivalve casts. The purpose of this article is to review the differences and similarities between these kinds of casting and offer guidelines for their use in individuals who have suffered a stroke.

The effects of circumferential pressure on the soleus muscle F-wave in healthy subjects

Circumferential pressure (CP) was shown to decrease muscle activity in subjects without neuromuscular disorders and in individuals with spinal cord injury and cerebrovascular accidents. The mechanism for this decrease is unknown although it is hypothesized to be spinal in origin. The purpose of this study was to investigate the effect CP has on the soleus F-wave. Results will help determine the mechanism CP uses to effect motoneuron reflex excitability. Thirty-seven healthy volunteers participated. A 16cm air-splint was placed around the calf and during the pressure phase of the experiment it was inflated to 40-45mm Hg. F-waves were evoked by supra maximally stimulating (20%>Mmax) the tibial nerve with a 0.1ms pulse at 0.2Hz using a bipolar surface electrode on the skin of the popliteal fossa. Fifty F-waves were recorded before (baseline), during, and 3) after CP was applied. F-waves were then identified and mean latency, persistence, and mean F/Mmax amplitude ratios were measured and calculated. Friedman Repeated Measures on Ranks tests were conducted on each of the three parameters (p⩽0.05). No statistically significant difference was found for any of the F-wave parameters evaluated. These results were contrary to previous CP studies that observed a significant decrease in muscle activity. Possible reasons for this discrepancy are discussed.

An investigation of the neurophysiologic effect of tone-reducing AFOs on reflex excitability in subjects with spasticity following stroke while standing

Tone-reducing ankle-foot orthoses (TRAFOs) are said to improve the control and functioning of spastic lower limbs by their biomechanic and neurophysiologic effects. Unfortunately, there is limited evidence in literature to support the theory that TRAFOs can effectively decrease spasticity in the foot and ankle neurophysiologically. The primary purpose of this investigation was to determine the neurophysiologic effect of TRAFOs on soleus muscle reflex excitability in subjects with spasticity following stroke while standing. A repeated-measures intervention study was conducted on 15 adult subjects with stroke who were recruited from the community. Custom-made articulated ankle-foot orthoses (AFOs) and TRAFOs with orthokinetic compression garments (OCGs) were fabricated for each subject. Five conditions were tested: (1) Shoes only, (2) AFO, (3) TRAFO, (4) TRAFO with OCG, (5) shoes only, to determine if the TRAFOs were most effective in decreasing spasticity as assessed by the ratio of maximum Hoffmann reflex amplitude to maximum muscle response amplitude (Hmax:Mmax ratio) of the soleus. The results found that there were no significant treatment effects for the interventions (F = 0.992, df = 2.167, p = 0.388), however, when analysed subject-by-subject, four subjects displayed significant increases in their Hmax:Mmax ratios to at least one treatment condition. Overall, the results demonstrated that the tone-reducing devices had no significant neurophysiologic effect on soleus reflex excitability in subjects with spasticity, however individual responses showed that the TRAFOs increased spasticity in some individuals.

Inhibitory effects of circumferential pressure on flexor carpi radialis H-reflex in adults with neurological deficits

The effects of circumferential air-splint pressure on the flexor carpi radialis H-reflex in 22 participants with cerebrovascular accident and 5 with spinal cord injury were examined. H-reflexes were assessed by measuring the peak-to-peak amplitude change before, during, and after circumferential pressure was applied to the forearm. 12 H-reflexes (H/M ratio: M = 25%; SD = 14) were recorded before pressure application to obtain a baseline value for comparison of data. A pneumatic 34-cm air splint inflated to 51-60 mmHg provided pressure around the forearm. H-reflex recordings were taken at 1, 3, and 5 min. during and 1 min. after application of pressure. A one-way analysis of variance with repeated measures was applied to compare pressure and postpressure measurements against the baseline value. Tukey multiple-comparison tests were used when significant F ratios were noted. Analysis indicated H-reflex amplitudes decreased significantly at 1, 3, and 5 min. during pressure and quickly returned to baseline when pressure was released. The study suggests air splints decreased the H-reflex in participants with neurological deficits and may be used in the upper extremity temporarily to reduce muscle activity associated with neurological dysfunction.

The effect of tone-reducing orthotic devices on soleus muscle reflex excitability while standing in patients with spasticity following stroke

Orthoses are commonly prescribed for the management of spasticity but their neurophysiologic effect on spasticity remains unsubstantiated. The purpose of this study was to investigate the effect of three tone-reducing devices (dynamic foot orthosis, muscle stretch, and orthokinetic compression garment) on soleus muscle reflex excitability while standing in patients with spasticity following stroke. A repeated measures intervention study was conducted on 13 patients with stroke selected from a sample of convenience. A custom-made dynamic foot orthosis, a range of motion walker to stretch the soleus muscle and class 1 and class 2 orthokinetic compression garments were assessed using the ratio of maximum Hoffmann reflex amplitude to maximum M-response amplitude (Hmax:Mmax) to determine their effect on soleus muscle reflex excitability. Only 10 subjects were able to complete the testing. There were no significant treatment effects for the interventions (F=1.208, df=3.232, p=0.328); however, when analyzed subject-by-subject, two subjects responded to the dynamic foot orthosis and one of those two subjects also responded to the class 1 orthokinetic compression garment. Overall, the results demonstrated that the tone-reducing devices had no significant effect on soleus reflex excitability suggesting that these tone-reducing orthotic devices have no significant neurophysiologic effect on spasticity.

What is the effect of taping along or across a muscle on motoneurone excitability? A study using Triceps Surae

Taping along the skin overlying lower trapezius reduces motoneurone excitability in healthy subjects [Alexander, C.M., Stynes, S., Thomas, A., Lewis, J., Harison, P.J., 2003. Does tape facilitate or inhibit the lower fibres of trapezius? Manual Therapy 8, 37-41]. It remains unclear whether this effect is: (a) specific to trapezius and (b) specific to the direction of application of the tape. In light of this, the excitability of another muscle was measured in order to see if these results were repeatable and independent of the muscle taped. Thus, the excitability of the medial and lateral gastrocnemius (MG and LG) and soleus (Sol) motoneurone pool was assessed using the Hoffman reflex (H reflex). The amplitude of this reflex was measured with the tape aligned across and then along the direction of the MG muscle fibres. Tape aligned across the fibres failed to affect motoneurone excitability (MG P=0.61, LG P=0.69, Sol P=0.17). Under tape and sports tape applied together aligned along the MG muscle reduced the excitability of both MG and LG (19% (P=0.01) and 13% (P=0.01), respectively). These observations suggest that any change to movement patterns with tape application cannot be explained by facilitation of the motoneurone excitability.

The effects of circumferential air-splint pressure on flexor carpi radialis H-reflex in subjects without neurological deficits

The purposes of this study were to investigate the effects of circumferential pressure on flexor carpi radialis (FCR) H-reflex in subjects without neuromuscular deficits and to evaluate the skin's contribution to this effect. FCR H-reflex was assessed in 43 subjects by measuring the peak-to-peak amplitude change before, during, and after circumferential pressure was applied to the forearm. Twelve H-reflexes (H/M ratio: M = 25%, SD = 14) were recorded before pressure application to obtain a baseline value (H(baseline)) to which all data were compared. A pneumatic 15 to 20-cm air splint inflated to 51-60 mmHg provided the pressure around the forearm. H-reflex recordings were taken at 1, 3, and 5 min. during (H(pressure)) and after pressure application. A second smaller study (placebo), in which the air splint was inflated to 0 mmHg, was conducted in 5 subjects to ensure that changes in reflex amplitudes were not a result of cutaneous effects. Two types of responses were observed in the FCR H-reflex following pressure application. One group of subjects significantly increased in H-reflex amplitude while another group decreased in H-reflex amplitude when compared to H(baseline). Regression analysis found that H(max) explained 37.2% of the variance when controlling for H(baseline). Subjects with larger H(max) showed an increase in H(pressure) while subjects with lower H(max) showed decreases in H(pressure) The placebo study revealed no differences in H-reflex amplitude from baseline values, implying that skin stimulation from the air splint has no role in the effects observed. The dichotomous result indicates that pressure influences the upper extremity differently than it does the lower extremity in certain individuals. Clinicians, using circumferential pressure as a therapeutic modality to lower muscle activity of the upper extremity, need to be cognizant that pressure may have contrasting effects on their patients.

Physiotherapy approaches in the treatment of ataxic multiple sclerosis: a pilot study

OBJECTIVE

This study was planned to investigate the efficacy of neuromuscular rehabilitation and Johnstone Pressure Splints in the patients who had ataxic multiple sclerosis.

METHODS

Twenty-six outpatients with multiple sclerosis were the subjects of the study. The control group (n = 13) was given neuromuscular rehabilitation, whereas the study group (n = 13) was treated with Johnstone Pressure Splints in addition.

RESULTS

In pre- and posttreatment data, significant differences were found in sensation, anterior balance, gait parameters, and Expanded Disability Status Scale (p < 0.05). An important difference was observed in walking-on-two-lines data within the groups (p < 0.05). There also was a statistically significant difference in pendular movements and dysdiadakokinesia (p < 0.05). When the posttreatment values were compared, there was no significant difference between sensation, anterior balance, gait parameters, equilibrium and nonequilibrium coordination tests, Expanded Disability Status Scale, cortical onset latency, and central conduction time of somatosensory evoked potentials and motor evoked potentials (p > 0.05). Comparison of values revealed an important difference in cortical onset-P37 peak amplitude of somatosensory evoked potentials (right limbs) in favor of the study group (p < 0.05).

CONCLUSIONS

According to our study, it was determined that physiotherapy approaches were effective to decrease the ataxia. We conclude that the combination of suitable physiotherapy techniques is effective multiple sclerosis rehabilitation.

The influence of rigid taping on peroneal latency in normal ankles

Traumatic ankle injury is a frequent clinical presentation. Ankle taping is commonly used in the prophylaxis of sprains and as an adjunct during rehabilitation of ankle injury. The mechanisms behind taping remain unclear however, one possible mechanism is improved proprioception and peroneal reflex responses. This study investigated the peroneal reflex response to rapid inversion (using a trapdoor) with different taping protocols. The dominant leg of 31 healthy subjects was tested in three conditions: no taping; simple prophylactic taping;and circumferential leg taping. A repeated measures ANOVA revealed no statistically significant effect across conditions or trials. The results suggest that neurophysiological responses to sudden inversion are not altered by mechanical or sensory input from taping in normal subjects.

Inhibitory casting decreases a vibratory inhibition index of the H-reflex in the spastic upper limb

OBJECTIVE

To test the hypothesis that application of an inhibitory cast to the spastic upper limb will decrease a vibratory inhibition index (VII) of the H-reflex in the spastic upper limb.

DESIGN

Prospective, nonrandomized, open-label trial.

SETTING

University tertiary care center.

PARTICIPANTS

Eight adults with upper limb spasticity.

INTERVENTION

Fiberglass cast application spanning the wrist to the upper arm.

MAIN OUTCOME MEASURE

The amplitude of the H-reflex with and without continuous 60Hz vibration to the tendon of the flexor carpi radialis was measured, and the VII was calculated using the formula: [H-reflex amplitude (vibrated)/H-reflex amplitude (control)] x 100%.

RESULTS

Mean VII decreased from baseline (70.7) on day 1 (67.6, p = .699), day 2 (55.9, p =.066), and day 3 (43.5, p = .033) of casting, and increased on day 4 (89.9, p = .146) after removal of the cast.

CONCLUSION

Findings lend support to the idea that during application of an inhibitory cast motor neuron excitability is decreased in the spastic upper limb.