Soleus H-Reflex Change in Poststroke Spasticity: Modulation due to Body Position

Purpose. This study is aimed at exploring how soleus H-reflex change in poststroke patients with spasticity influenced by body position. Materials and Methods. Twenty-four stroke patients with spastic hemiplegia and twelve age-matched healthy controls were investigated. Maximal Hoffmann-reflex (Hmax) and motor potential (Mmax) were elicited at the popliteal fossa in both prone and standing positions, respectively, and the Hmax/Mmax ratio at each body position was determined. Compare changes in reflex behavior in both spastic and contralateral muscles of stroke survivors in prone and standing positions, and match healthy subjects in the same position. Results. In healthy subjects, Hmax and Hmax/Mmax ratios were significantly decreased in the standing position compared to the prone position (Hmax: p = 0.000 , Hmax/Mmax: p = 0.016 ). However, Hmax/Mmax ratios were increased in standing position on both sides in poststroke patients with spasticity (unaffected side: p = 0.006 , affected side: p = 0.095 ). The Hmax and Hmax/Mmax ratios were significantly more increased on the affected side than unaffected side irrespective of the position. Conclusions. The motor neuron excitability of both sides was not suppressed but instead upregulated in the standing position in subjects with spasticity, which may suggest that there was abnormal regulation of the Ia pathway on both sides.

Electrophysiological comparison study between effectiveness of the treatment modalities (Baclofen and Tizanidine drug) on spasticity management

Background: Baclofen and tizanidine are both used for the treatment of muscle spasticity of spinal origin. patients and methods: This study was conducted in Ibn Al-Quf hospital for spinal cord injuries from the period December 2011 to June 2012. All of the participants gave written consent to participate in the study. The patients were divided into 2 groups: Group (I): Baclofen with physiotherapy treatment group; and Group (II): Tizanidine with physiotherapy treatment groups .H-reflex measurements were performed. parameters were studied: H-reflex latency, M wave latency, H-reflex conduction velocity, H-reflex duration, H-reflex amplitude. Results: All the patients had symptoms of spasticity at any time during the day with a Modified Ashworth Scale (MAS) before performing the H-reflex study. highly significant improvement in the H/M ratio when comparing positive controls to the two groups while the H/M ratio in the negative controls shows no significant difference with group I and group II. A significant correlation was noticed between the height of control subjects & H-reflex latency (P= 0.002), significant positive correlation was also found (P=0.028) between the height & M wave latency in the control subjects, The results revealed that the type of treatment did not affect the H-reflex and F wave parameters except for the H/M ratio. conclusion: H-reflex can provide information regarding neural function after spinal cord injury and the H/M ratio can be used as a good indicator for both spasticity assessment and response to treatment. Tizanidine hydrochloride is useful in the management of spasticity caused by SCI and can be used as a routine drug treatment although liver function tests should be periodically monitored.

Endurance Trained Athletes Do Not per se Have Higher Hoffmann Reflexes Than Recreationally Active Controls

The impact of endurance training on spinal neural circuitries remains largely unknown. Some studies have reported higher H-reflexes in endurance trained athletes and therefore, adaptations within the Ia afferent pathways after long term endurance training have been suggested. In the present study we tested the hypothesis that cyclists (n = 12) demonstrate higher Hoffmann reflexes (H-reflexes) compared to recreationally active controls (n = 10). Notwithstanding, highly significant differences in endurance performance (VO2peak: 60.6 for cyclists vs. 46.3 ml/min/kg for controls (p < 0.001) there was no difference in the size of the SOL H-reflex between cyclists and controls (Hmax/Mmax ratio 61.3 vs. 60.0%, respectively (p = 0.840). Further analyses of the H and M recruitment curves for SOL revealed a significant steeper slope of the M recruitment curve in the group of cyclists (76.2 ± 3.8° vs. 72.0 ± 4.4°, p = 0.046) without a difference in the H-recruitment curve (84.6 ± 3.0° vs. 85.0 ± 2.8°, p = 0.784) compared to the control group. Cycling is classified as an endurance sport and thus the findings of the present study do not further support the assumption that long-term aerobic training leads to a general increase of the H-reflex. Amongst methodological differences in assessing the H-reflex, the training-specific sensorimotor control of the endurance sport itself might differently affect the responsiveness of spinal motoneurons on Ia-afferent inputs.

Effects of Different Tissue Flossing Applications on Range of Motion, Maximum Voluntary Contraction, and H-Reflex in Young Martial Arts Fighters

The purpose of this study was to investigate the effects of tissue flossing applied to the ankle joint or to the calf muscles, on ankle joint flexibility, plantarflexor strength and soleus H reflex. Eleven young (16.6 ± 1.2 years) martial arts fighters were exposed to three different intervention protocols in distinct sessions. The interventions consisted of wrapping the ankle (ANKLE) or calf (CALF) with an elastic band for 3 sets of 2 min (2 min rest) to create vascular occlusion. A third intervention without wrapping the elastic band served as a control condition (CON). Active range of motion for ankle (AROM), plantarflexor maximum voluntary contraction (MVC), and soleus H reflex were assessed before (PRE), after (POST), and 10 min after (POST10) the intervention. The H reflex, level of pain (NRS) and wrapping pressure were also assessed during the intervention. Both CALF and ANKLE protocols induced a significant drop in H reflex during the intervention. However, the CALF protocol resulted in a significantly larger H reflex reduction during and after the flossing intervention (medium to large effect size). H reflexes returned to baseline levels 10 min after the intervention in all conditions. AROM and MVC were unaffected by any intervention. The results of this study suggest that tissue flossing can decrease the muscle soleus H reflex particularly when elastic band is wrapped around the calf muscles. However, the observed changes at the spinal level did not translate into higher ankle joint flexibility or plantarflexor strength.

Maximal strength training-induced increase in efferent neural drive is not reflected in relative protein expression of SERCA

Introduction Maximal strength training (MST), performed with heavy loads (~ 90% of one repetition maximum; 1RM) and few repetitions, yields large improvements in efferent neural drive, skeletal muscle force production, and skeletal muscle efficiency. However, it is elusive whether neural adaptations following such high intensity strength training may be accompanied by alterations in energy-demanding muscular factors. Methods Sixteen healthy young males (24 ± 4 years) were randomized to MST 3 times per week for 8 weeks (n = 8), or a control group (CG; n = 8). Measurements included 1RM and rate of force development (RFD), and evoked potentials recordings (V-wave and H-reflex normalized to M-wave (M) in the soleus muscle) applied to assess efferent neural drive to maximally contracting skeletal muscle. Biopsies were obtained from vastus lateralis and analyzed by western blots and real-time PCR to investigate the relative protein expression and mRNA expression of Sarcoplasmic Reticulum Ca2+ ATPase (SERCA) 1 and SERCA2. Results Significant improvements in 1RM (17 ± 9%; p < 0.001) and early (0–100 ms), late (0–200 ms) and maximal RFD (31–53%; p < 0.01) were observed after MST, accompanied by increased maximal Vmax/Msup-ratio (9 ± 14%; p = 0.046), with no change in H-reflex to M-wave ratio. No changes were observed in the CG. No pre- to post-training differences were found in mRNA or protein expressions of SERCA1 and SERCA2 in either group. Conclusion MST increased efferent neural drive to maximally contracting skeletal muscle, causing improved force production. No change was observed in SERCA expression, indicating that responses to high intensity strength training may predominantly be governed by neural adaptations.

Electrophysiological Evaluation of the Modified Ashworth Scale in Assessment of Post Stroke Ankle Plantar Spasticity

Background: Spasticity is a common impairment following upper motor neuron lesions such as stroke. The appropriate measure of muscle spasticity, using validated tools to evaluate the outcome of therapies is important in clinical and research settings. Objective: To determine the concurrent criterion-related validity of the Modified Ashworth Scale in assessing post stroke Ankle flexor muscle spasticity based on its correlation with Modified Tardieu scale and the H-reflex tests. Methods: A total of 35 adult stroke participants underwent clinical and electrophysiological assessment of the ankle flexor muscle spasticity on the affected side. The primary outcome measures were: MMAS grade, R2−R1 of the MTS; and the H-reflex indices of H-max/M-max ratio. Results: Correlations tests revealed the correlation between the MMAS and MTS but did not reveal significant associations between the MMAS and the H-reflex tests. Conclusions: This study suggests that the MMAS may not be a valid tool to evaluate the ankle flexor muscle spasticity in these stroke participants. Key words: Stroke, spasticity, Modified Ashworth Scale, Tardieu Scale, H-reflex, criterion validity.