Efecto inmediato de la crioterapia sobre la excitabilidad refleja en personas con espasticidad post-ECV / Immediate effect of cryotherapy on the spastic reflex excitability in people with spasticity post-stroke

Introducción: Existe controversia sobre los efectos terapéuticos de la crioterapia en el músculo espástico y las implicaciones clínicas que fundamentan su uso como coadyuvante en el proceso de rehabilitación. Objetivo: Evaluar el efecto inmediato de la aplicación del paquete de hielo sobre la excitabilidad refleja en la musculatura plantiflexora espástica en personas post-ECV. Métodolos: Estudio experimental de mediciones repetidas con asignación aleatoria a dos grupos de intervención: Grupo Experimental (n=10) y Grupo Control (n=5). Se registró latencia (ms), duración (ms) y amplitud (mV) de las ondas M y H y el índice de amplitud Hmáximo/Mmáximo (%) antes y después de la crioterapia o reposo. Los participantes fueron quince individuos de ambos géneros con hemiparesia espástica post-ECV, edad media de 60,7±10,7años, mediana tiempo de evolución 36 meses (RIC17-49). No hubo diferencias significativas en las características basales entre los grupos de intervención. Resultados: La crioterapia induce un aumento estadísticamente significativo en la latencia de la onda H (32,9±3,3 vs. 34,9±3,6ms, p<0,001) y M (8,0±1,9 vs. 9,4±2,4ms, p<0,05) y en la duración de la onda M (6,3±1,3 vs. 9,8±2,2ms, p<0,001) y H (7,2±1,6 vs. 9,9± 2,0ms, p<0,001). No se determinaron cambios significativos en la amplitud, ni en el índice Hmáx/Mmáx. Conclusiones: Nuestros hallazgos sugieren que el enfriamiento puede ser útil para el tratamiento de la espasticidad, pues retrasa la respuesta muscular evocada por estimulación eléctrica directa y refleja. A su vez, prolonga el período refractario del potencial de acción, por lo cual se requeriría más tiempo para activar las fibras musculares.

Introduction: There is controversy about the therapeutic effects of cryotherapy on spasticity and clinical implications underlying its use as an adjunct in the rehabilitation process. Objective: To evaluate the immediate effect of the application of ice pack on the H-reflex excitability in spastic muscles post-stroke people. Methods: A randomized experimental study of repeated measurements, with two intervention groups, was performed: Experimental group (n=10) and control group (n=5). Latency (ms) duration (ms) and amplitude (mV) of M and H waves and the amplitude index Hmáximo / Mmáximo (%) were recorded before and after cryotherapy or rest. The participants were fifteen subjects with spastic hemiparesis post-stroke were screened, mean age 60.7±10.7 years, median of injury duration 36 months (IQR17-49). There were no significant differences in baseline characteristics between the intervention groups. Results: Cryotherapy induces a statistically significant increase in the H wave latency (32.9±3.3 vs. 34.9± 3.6ms, p<0,001) and M wave (8.0±1.9 vs. 2.4ms±9.4, p<0.05); as well as, increase was observed in the duration of the M wave (6.3±1.3 vs. 9.8±2.2ms, p<0.001) and H (7.2±1.6 vs. 9.9±2.0ms, p<0.001). No significant changes in the amplitude or the Hmax/Mmax ratio were determined. There were no differences between the H-reflex or the M-wave variables recorded before and after in the control group. Conclusions: Our findings suggest that cooling may be useful for the treatment of spasticity, due to it delays muscle response evoked by direct and reflects electrical stimulation. Simultaneously, cooling prolongs the refractory period of the action potential, whereby more time is required to activate the muscle fibers.

Clinical importance of F-waves as a prognostic factor in Guillain-Barré syndrome in children / 소아과

PURPOSE: A limited number of studies have examined the link between F-wave abnormalities and clinical presentation in pediatric Guillain-Barré syndrome (GBS). Therefore, this study examined the importance of F-wave abnormalities as a prognostic factor in pediatric GBS patients. METHODS: The records and electrodiagnostic studies (EDS) of 70 GBS patients were retrospectively evaluated, and divided into 2 groups according to the results of EDS. Group A (n=33) presented with F-wave abnormalities, and group B (n=26) exhibited normal findings. We compared laboratory reports, clinical features, response to treatment, and prognosis between the 2 groups. RESULTS: Motor weakness was the most frequently observed symptom for either group. Clinically, the incidence of fever and upper respiratory symptoms differed between the 2 groups, while the prevalence of abnormal deep tendon reflex (DTR) was significantly higher in group A than B (P<0.05). Patients diagnosed with GBS had received intravenous immunoglobulin treatment: 94% in group A and 58% in group B. Furthermore, significantly greater numbers of patients in group A showed H-reflex abnormalities and poor prognosis compared with group B (P<0.05). CONCLUSION: This study demonstrated that F-waves are a clinically important prognostic factor in GBS. F-wave abnormalities were associated with abnormal DTR and poor prognosis in patients. Limited studies have examined the link between F-wave abnormalities and clinical results; therefore, further randomized controlled studies are needed to confirm the clinical characteristics and efficacy of treatments.

Intraoperative Monitoring and Mapping of the Functional Integrity of the Brainstem

The risk of iatrogenic damage is very high in surgical interventions in or around the brainstem. However, surgical techniques and intraoperative neuromonitoring (ION) have evolved sufficiently to increase the likelihood of successful functional outcomes in many patients. We present a critical review of the methodologies available for intraoperative monitoring and mapping of the brainstem. There are three main groups of techniques that can be used to assess the functional integrity of the brainstem: 1) mapping, which provides rapid anatomical identification of neural structures using electrical stimulation with a hand-held probe, 2) monitoring, which provides real-time information about the functional integrity of the nervous tissue, and 3) techniques involving the examination of brainstem reflexes in the operating room, which allows for the evaluation of the reflex responses that are known to be crucial for most brainstem functions. These include the blink reflex, which is already in use, and other brainstem reflexes that are being explored, such as the masseter H-reflex. This is still under development but is likely to have important functional consequences. Today an abundant armory of ION methods is available for the monitoring and mapping of the functional integrity of the brainstem during surgery. ION methods are essential in surgery either in or around the brainstem; they facilitate the removal of lesions and contribute to notable improvements in the functional outcomes of patients.

Intraoperative Monitoring and Mapping of the Functional Integrity of the Brainstem

The risk of iatrogenic damage is very high in surgical interventions in or around the brainstem. However, surgical techniques and intraoperative neuromonitoring (ION) have evolved sufficiently to increase the likelihood of successful functional outcomes in many patients. We present a critical review of the methodologies available for intraoperative monitoring and mapping of the brainstem. There are three main groups of techniques that can be used to assess the functional integrity of the brainstem: 1) mapping, which provides rapid anatomical identification of neural structures using electrical stimulation with a hand-held probe, 2) monitoring, which provides real-time information about the functional integrity of the nervous tissue, and 3) techniques involving the examination of brainstem reflexes in the operating room, which allows for the evaluation of the reflex responses that are known to be crucial for most brainstem functions. These include the blink reflex, which is already in use, and other brainstem reflexes that are being explored, such as the masseter H-reflex. This is still under development but is likely to have important functional consequences. Today an abundant armory of ION methods is available for the monitoring and mapping of the functional integrity of the brainstem during surgery. ION methods are essential in surgery either in or around the brainstem; they facilitate the removal of lesions and contribute to notable improvements in the functional outcomes of patients.

Post-activation depression of the lower extremities in stroke patients with spasticity and spastic equinovarus deformity / Depressão pós-ativação das extremidades inferiores de pacientes com acidente vascular cerebral que apresentam espasticidade e deformidade equinovarus por espasticidade

This study aimed to investigate changes of post-activation depression in two groups of patients with or without spastic equinovarus deformity (SED). Paired and independent t-tests were used to compare post-activation depression within and between the groups, respectively. There was a significant positive correlation between diminished post-activation depression and spasticity severity. The soleus and tibialis anterior (TA) post-activation depression values were significantly decreased on the affected sides of patients with SED compared to those without. In patients without SED, the soleus post-activation depression was significantly decreased on the affected side; however, TA post-activation depression was higher on the affected side. Both the soleus and TA become active, but the onset time may be different. The imbalanced muscle tone between the soleus and TA in the early stage after stroke may be related to equinus deformity.

O principal objetivo deste estudo é a investigação da depressão pós-ativação em pacientes com deformidade equinovarus espástica (DEE). Os pacientes foram divididos em dois grupos. Student-t testes pareados e independentes foram utilizados para comparar a depressão pós-ativação intra- e inter-grupos, respectivamente. Houve uma correlação positiva significativa entre a diminuição da depressão pós-ativação e a gravidade da espasticidade. A depressão pós-ativação dos músculos sóleo e tibial anterior (TA) estavam significativamente diminuídas no lado afetado dos pacientes com SEE em relação aos membros sem SEE. Em pacientes sem SEE, a depressão pós-ativação do músculo sóleo encontrava-se significativamente diminuída do lado afetado. No entanto, a depressão pós-ativação do músculo TA era maior no lado afetado que no lado não afetado. Tanto o sóleo quanto o TA serão ativados, mas o tempo para isso pode ser diferente. O desequilíbrio entre o tônus dos músculos sóleo e TA nos estágios iniciais pode estar relacionado à deformidade equina.

Role of nerve stimulation at Erb point in early diagnosis of Guillain-Barré syndrome in children / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To study the role of proximal nerve stimulation at Erb point in the early diagnosis of Guillain-Barré syndrome (GBS) in children.</p><p><b>METHODS</b>Thirty-two children who were diagnosed with GBS between October 2013 and December 2014 received neurophysiological examination. Thirty healthy children were used as controls. Compound muscle action potentials and distal motor latency of the median and ulnar nerves were determined and analyzed after nerve stimulation at the wrist, elbow, and Erb point in the two groups. Moreover, F-wave latency of the median nerve and H-reflex latency of the tibial nerve were measured and analyzed in the two groups.</p><p><b>RESULTS</b>The F-wave and H-reflex latencies were significantly longer in the patient group than in the control group (P<0.05). In thirty-two patients, the numbers of patients with abnormal amplitude, abnormal latency, and conduction block at Erb's point were 24 (75%), 22 (69%), and 20 (62%), respectively. The patient group had significantly lower amplitudes but significantly longer latencies of the ulnar and median nerves at Erb point than the control group (P<0.05). There were no significant differences in the amplitudes and latencies at the wrist and elbow between the two groups (P>0.05).</p><p><b>CONCLUSIONS</b>The nerve stimulation at Erb point holds promise as a routine examination for the early diagnosis of GBS.</p>

Evaluating the Differential Electrophysiological Effects of the Focal Vibrator on the Tendon and Muscle Belly in Healthy People

OBJECTIVE: To investigate the electrophysiological effects of focal vibration on the tendon and muscle belly in healthy people. METHODS: The miniaturized focal vibrator consisted of an unbalanced mass rotating offset and wireless controller. The parameters of vibratory stimulation were adjusted on a flat rigid surface as 65 microm at 70 Hz. Two consecutive tests on the different vibration sites were conducted in 10 healthy volunteers (test 1, the Achilles tendon; test 2, the muscle belly on the medial head of the gastrocnemius). The Hoffman (H)-reflex was measured 7 times during each test. The minimal H-reflex latency, maximal amplitude of H-reflex (Hmax), and maximal amplitude of the M-response (Mmax) were acquired. The ratio of Hmax and Mmax (HMR) and the vibratory inhibition index (VII: the ratio of the Hmax after vibration and Hmax before vibration) were calculated. The changes in parameters according to the time and site of stimulation were analyzed using the generalized estimating equation methods. RESULTS: All subjects completed the two tests without serious adverse effects. The minimal H-reflex latency did not show significant changes over time (Wald test: chi2=11.62, p=0.07), and between the two sites (chi2=0.42, p=0.52). The changes in Hmax (chi2=53.74, p<0.01), HMR (chi2=20.49, p<0.01), and VII (chi2=13.16, p=0.02) were significant over time with the adjustment of sites. These parameters were reduced at all time points compared to the baseline, but the decrements reverted instantly after the cessation of stimulation. When adjusted over time, a 1.99-mV decrease in the Hmax (chi2=4.02, p=0.04) and a 9.02% decrease in the VII (chi2=4.54, p=0.03) were observed when the muscle belly was vibrated compared to the tendon. CONCLUSION: The differential electrophysiological effects of focal vibration were verified. The muscle belly may be the more effective site for reducing the H-reflex compared to the tendon. This study provides the neurophysiological basis for a selective and safe rehabilitation program for spasticity management with focal vibration.

[Evaluation of lumbosacral manipulation on motoneuronal activity in patients with low back pain]

Spinal manipulation is a manual technique commonly used for the treatment of low back pain. The physiologic mechanisms of spinal manipulation are largely unknown. One basic physiologic response to spinal manipulation [SM] is alternation in Moto neuronal activity, as assessed by the Hoffmann reflex [H-reflex] technique. The purpose of this study was to determine the effect of spinal manipulation on amplitude and onset latency of H-reflexes and on H/M amplitude ratio in patients with low back pain. It was a clinical trial with IRCT201203069222N1 Registration code. Ffifty eight patients with low back pain aged between 20-60 years were included. Tibial nerve H reflex and M wave were recorded before and after Lumbosacral spinal manipulation. The data was analyzed by SPSS 16. Lumbosacral manipulation significantly decrease amplitude of H reflex and H/M amplitude ratio [P<0.05]. It had not significantly effect on H reflex latency or M wave amplitude and latency [P>0.05]. Lumbosacral manipulation produces attenuation of alpha motoneuronal excitability. These findings support of this theory that manual spinal therapy can lead to reduction in muscle tone.

Establishment of H reflex model in mice with minimal insult and measurement of nerve conduction velocity / 生理学报

The aim of the present study was to establish a minimally invasive H reflex model in mice for the benefit of the research of clinical spinal cord injury and related diseases. Minimally invasive surgery was performed in hind limb of Kunming mouse under light anesthesia. The skin was incised at the point of one-third of the distance from greater trochanter to the base of the cauda. A pair of fine copper conductors were inserted into the shallow muscle using a syringe needle. After the needles were withdrawed, the retained conductors were ligated and fixed with the tissues surrounding the sciatic nerve as the first pair of stimulating electrodes. Another pair of conductors were inserted and fixed in medial malleolus close to the tibial nerve as the second stimulating electrodes. Copper conductor was inserted passing the skin above the proximal end of the metatarsal and fixed as the recording electrode. The reference electrode was placed at the walking pad in the base of the big toe using the same method. Electromyography (EMG) was used to record M and H waves in planta pedis muscles. The stimulus was a square wave with a width of 0.2 ms and frequency of 0.3 Hz. The latency time of the M and H waves which were induced from the two pairs of stimulating electrodes was recorded. Nerve conduction velocity (NCV) was then calculated from the distance between the cathodes of the stimulating electrodes and the latency time difference of M or H waves. The result showed the achievement ratios of H reflex induction were 92.73% and 81.82% in sciatic and tibial nerves, respectively. The latency time of H wave was about 7~10 ms. Motor nerve conduction velocity (MNCV) obtained was (25.84 ± 4.70) m/s (n = 35), while sensory nerve conduction velocity (SNCV) was (31.45 ± 7.30) m/s (n = 35). The method established in the present paper is simple to practice, does slight harm to the animal, and can produce waveforms with little interference. With these advantages, the method can be applied for the study of the latency of H reflex, and it is suitable for the researches which demands good physical condition of experimental animal during H reflex study. This model can also be applied to the detection of SNCV and MNCV.

Efecto de la movilización articular sobre la amplitud del Reflejo H en personas con espasticidad / Effect of joint mobilization on the H Reflex amplitude in people with spasticity / Efeito da mobilização articular sobre a amplitude do reflexo H em pessoas com espasticidade

Objetivo: Determinar el efecto de la movilización articular del tobillo sobre la amplitud del reflejo H del músculo sóleo en personas con espasticidad. Materiales y métodos: Se realizó un cuasiexperimento con diseño cruzado y enmascaramiento simple en 24 personas voluntarias aleatorizadas para iniciar en el estudio control o experimental. Se aplicó tracción y oscilación rítmica en la articulación del tobillo durante cinco minutos. Se midieron los cambios en la amplitud de la onda H del reflejo de Hoffmann, como equivalente eléctrico del reflejo espinal monosináptico, estimulando el nervio tibial a nivel de la fosa poplítea y captando en el músculo sóleo. A cada persona se le realizaron 12 mediciones: basal, durante la movilización y después de finalizada. Se calcularon las variaciones de la amplitud de la onda H respecto a la medida basal. Para cada una de las mediciones se realizó una prueba de hipótesis (t de Student). Resultados: En los grupos de pacientes con lesión cerebral y lesión medular incompleta se encontró una diferencia significativa entre las medias de ambos estudios respecto a la variación de la amplitud de la onda H durante la aplicación de la movilización articular con disminución en el experimental y aumento en el control; en contraste, no se encontraron diferencias significativas después de finalizada la movilización. En pacientes con lesión medular completa no se observaron diferencias significativas en ninguna de las mediciones. Conclusiones: Se demuestra la eficacia de la movilización articular para la disminución de la amplitud de la onda H durante la maniobra de movilización en pacientes con lesión cerebral o lesión medular incompleta, pero sin ningún efecto residual después de finalizada. La investigación no arrojó evidencia para la disminución de la amplitud en lesión medular completa. Se sugiere replantear las intervenciones terapéuticas para disminución del tono muscular basadas en la movilización articular.

Objective: To determine the effect of ankle joint mobilization on the H reflex amplitude of the soleus muscle in people with spasticity. Materials and methods: A quasi-experimental study with crossover design and simple masking was conducted in 24 randomized subjects to initiate the control or experimental group. Traction and rhythmic oscillation were applied for five minutes to the ankle joint. H wave amplitude changes of Hoffmann reflex (electrical equivalent of the monosynaptic spinal reflex) was assessed, stimulating the tibial nerve at the level of the popliteal fossa and recording in the soleus muscle. In each subject 12 measurements were taken: basal rate, during and after mobilization. Changes in H reflex amplitude were calculated in relation to basal measurement. For each measurement a hypothesis test was performed (Student t test). Results: In groups of patients with brain injury and incomplete spinal cord injury, a significant difference was found between measurements of both studies, concerning variation in H reflex amplitude during the application of joint mobilization techniques, with a decrease in the experimental group and an increase in the control group. In contrast, no significant differences were found after mobilization therapy. Patients with complete spinal cord injury showed no significant differences in any measurements. Conclusion: We demonstrate the effectiveness of joint mobilization in the decrease of H reflex amplitude in patients with brain injury or incomplete spinal cord injury during the mobilization maneuver, but no residual effect after completion of the trial. This research showed no evidence regarding excitability reduction in complete spinal cord injury. We suggest that therapeutic interventions to decrease muscle tone based on the joint mobilization should be reconsidered.

Objetivo: Determinar o efeito da mobilização articular do tornozelo sobre a amplitude do reflexo H do músculo sóleo em pessoas com espasticidade. Materiais e métodos: se realizou um quase-experimento com desenho cruzado e mascaramento simples em 24 pessoas voluntárias aleatorizadas para iniciar o estudo controle ou experimental. Aplicou-se tração e oscilação rítmica na articulação do tornozelo durante cinco minutos. Mediram-se as mudanças na amplitude da onda H do reflexo de Hoffmann, como equivalente elétrico do reflexo espinhal monossináptico estimulando o nervo tibial no nível da fossa poplítea e captando no músculo sóleo. A cada uma das pessoas realizaram-lhes 12 medições: basal, durante a mobilização e depois de finalizada. Calcularam-se as variações da amplitude da onda H em relação à medida basal. Para cada uma das medições realizou-se uma prova de hipótese (t de Student). Resultados: Nos grupos de pacientes com lesão cerebral e lesão medular incompleta encontrou-se uma diferença significativa entres as médias de ambos os estudos com relação à variação da amplitude da onda H durante a aplicação da mobilização articular com diminuição no experimental e aumento no controle; em contraste, não se encontraram diferenças significativas depois de finalizada a mobilização. Em pacientes com lesão medular completa não se observaram diferenças significativas em nenhuma das medições. Conclusões: Se demonstra a eficácia da mobilização articular para a diminuição da amplitude da onda H durante a manobra de mobilização em pacientes com lesão cerebral ou lesão medular incompleta, mas sem nenhum efeito residual depois de finalizada. A pesquisa não produziu evidência para a diminuição da amplitude em lesão medular completa. Sugere-se reformular as intervenções terapêuticas para diminuição do tom muscular baseadas na mobilização articular. Palavras chave: Manipulações musculoesqueléticas, terapia por exercício, tom muscular, espasticidade muscular.

[How could FAIR test modify the H reflex in gastrocnemius muscle in patients with piriformis syndrome?]

Priformis syndrome [PS] is defined by a loose cluster of symptoms arising from entrapment of one or both divisions of the sciatic nerve as they pass the sciatic notch. This paper presents a method of using the H-reflex as an aid in the diagnosis of PS. Forcible pressure from the priformis muscle on the sciatic nerve can be induced by internal rotation of an affected limb in an adducted and flexed position [FAIR]. This pressure is reflected in a delay of the H-reflex. The length of delay seen in 15 legs of 14 patients who met the criteria for PS is compared with that seen in 7 unaffected contralateral limbs. Mean delay of H-reflex was 2.346 msec for affected legs and 0.368 msec for the combined control groups [p<0.01]. There were no significant differences in delay latency between control group and amplitude between all groups [p>0.05]

Effects of 100 Hz sinusoidal vibration on H reflex and M wave in rat soleus muscle following immobilization / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of 100 Hz sinusoidal vibration on H reflex and M wave in rat soleus muscle following immobilization.</p><p><b>METHODS</b>The immobilization of rat soleus muscle was induced as a disuse muscle model, and 100 Hz sinusoidal vibration was generated by a vibrator and applied to the immobilized soleus muscle, then the changes of H reflex and M wave in muscle were observed after 14 d.</p><p><b>RESULTS</b>Compared to control, after 14 d of immobilization M(max) in soleus muscle decreased (P<0.01), stimulus threshold and S(max) increased (P<0.01); Hmax and H(max)/M(max) decreased (P<0.05, S(max) increased (P<0.05). Compared to immobilized soleus muscle, after 14 d of immobilization with 100 Hz sinusoidal vibration, the M(max) increased(P<0.01), stimulus threshold and S(Mmax) decreased (P<0.05), H(max) (P<0.01) increased and H(max)/M(max) increased (P<0.05).</p><p><b>CONCLUSION</b>100 Hz sinusoidal vibration plays a significant antagonist role against the changes in H reflex and M wave in rat soleus muscle following immobilization.</p>

Spasticity and Electrophysiologic Changes after Extracorporeal Shock Wave Therapy on Gastrocnemius

OBJECTIVE: To evaluate the spasticity and electrophysiologic effects of applying extracorporeal shock wave therapy (ESWT) to the gastrocnemius by studying F wave and H-reflex. METHOD: Ten healthy adults and 10 hemiplegic stroke patients with ankle plantarflexor spasticity received one session of ESWT on the medial head of the gastrocnemius. The modified Ashworth scale (MAS), tibial nerve conduction, F wave, and H-reflex results were measured before and immediately after the treatment. The Visual Analogue Scale (VAS) was used during ESWT to measure the side effects, such as pain. RESULTS: There were no significant effects of ESWT on the conduction velocity, distal latency and amplitude of tibial nerve conduction, minimal latency of tibial nerve F wave, latency, or H-M ratio of H-reflex in either the healthy or stroke group. However, the MAS of plantarflexor was significantly reduced from 2.67+/-1.15 to 1.22+/-1.03 (p<0.05) after applying ESWT in the stroke group. CONCLUSION: After applying ESWT on the gastrocnemius in stroke patients, the spasticity of the ankle plantarflexor was significantly improved, with no changes of F wave or H-reflex parameters. Further studies are needed to evaluate the mechanisms of the antispastic effect of ESWT.

Using standing postures as a practical alternative to gait analysis for assessing normal neuromotor activity variation of the ankle muscle antagonists: a soleus H-reflex and EMG activity study comparing patients with hemiplegia to healthy subjects / Uso de posturas erguidas como alternativa práctica al análisis de marcha para evaluar la actividad neuromotora normal de los antagonistas del tobillo: una comparación entre pacientes hemiplégicos y sujetos normales

The purpose of this study was to evaluate and compare the soleus H-reflex amplitudes recorded in three standing postures between a group of patients with stroke and a group of healthy subjects. Nine ambulatory patients were compared with 10 healthy subjects. Measures were recorded during quiet standing (QS), heels raised (PO) and with the foot of the measured leg held just off the ground while standing on the opposite leg (SW). The results showed that patients, as opposed to the healthy group, did not inhibit soleus H-reflex in the SW posture. As opposed to evaluating ankle motor control during gait, the PO and SW standing postures appeared to offer a practical and objective method to assess soleus H-reflex when the purpose is to determine impairment (or recovery) of ankle neuromotor control in stroke survivors.

El propósito de este estudio fue evaluar y comparar la amplitud de el reflejo H en el músculo sóleo en tres posturas en la posición de pie entre un grupo de pacientes con hemiplejia y un grupo de individuos sanos. Nueve pacientes ambulatorios fueron comparados con diez individuos sanos. Registros fueron obtenidos en la posición de pie bipedal (QS), bipedal con talones elevados (PO), y unipedal manteniendo el pie afectado ligeramente elevado sin contacto con el piso (SW). Los resultados mostraron que los pacientes, en contraste con el el grupo sano, no presentaron inhibición del reflejo H en la postura SW. Comparado a registros del reflejo H obtenidos durante la marcha, aquellos obtenidos con las posturas PO y SW aparecen como un método más práctico y objetivo para evaluar el reflejo H del soleus si el propósito es determinar nivel de pérdida (o recuperación) de el control neuromotor del tobillo en pacientes con hemiplejia.

Using standing postures as a practical alternative to gait analysis for assessing normal neuromotor activity variation of the ankle muscle antagonists: a soleus H-reflex and EMG activity study / Uso de posturas erguidas como alternativa al análisis de marcha para evaluar la variación en la actividad neuromotora de los músculos antagonistas del tobillo: un estudio utilizando el reflejo H del músculo sóleo y EMG

Soleus and tibialis anterior muscle EMG and soleus H-reflex are widely used to study ankle motor control during gait. Normally, the soleus H-reflex amplitude and EMG activity varies greatly through the course of walking. The examining of these events during walking requires space and resources that are generally found only in research oriented facilities, making difficult a more practical use. Earlier reports have suggested that normal variation of the soleus H-reflex and EMG could be determined from standing postures. Therefore, the main purpose of this study was to examine and determine which standing postures would reproduce the normal neuromotor variation of the ankle muscle antagonists. A total of five postures were investigated. The results of this study demonstrated that the normal variation in the soleus H-reflex amplitude and the associated EMG activity can be comparably reproduced from two selected standing postures (PO and SW). The described method presents a practical and functional alternative to gait analysis when the goal is determining normal ankle neuromotor control.

La actividad electromiográfica (EMG) de los músculos tibial anterior y sóleo junto al reflejo H del sóleo han sido extensamente usados en el estudio del control motor del tobillo durante la marcha. Normalmente, la amplitud del reflejo H del sóleo y EMG varía ampliamente durante el curso de la marcha. El estudio de estos eventos durante la marcha requiere de espacio y equipamiento generalmente sólo disponible en laboratorios de investigación, por lo que resulta difícil su aplicación práctica. Previos estudios han sugerido que la variación normal del reflejo H del sóleo y EMG pudiese ser obtenida utilizando posturas en la posición de pie. El propósito principal de este estudio fue examinar y determinar qué posturas reproducirían la variación neuromotora normal en los músculos antagonistas del tobillo. Un total de cinco posturas fueron investigadas. Los resultados de este estudio demostraron que la variación normal de la amplitud del reflejo H del sóleo y EMG asociada, puede ser similarmente reproducida a partir de dos posturas (PO y SW). El método descrito presenta una alternativa práctica y funcional a la marcha, cuando el objetivo es la determinación del control neuromotor normal en el tobillo.

The Effect of High Frequency Repetitive Transcranial Magnetic Stimulation on the Motor Function in Post-Stroke Patients

OBJECTIVE: To evaluate the effects of high frequency repetitive transcranial magnetic stimulation (rTMS) of the affected hemisphere on the motor recovery and spasticity in chronic post-stroke hemiplegic patients. METHOD: Thirteen chronic stroke hemiplegic patients were randomized to receive real and sham rTMS. rTMS was carried out 10 times at a frequency of 10 Hz with 10 s stimulation followed by 50 s rest, totalling 1,000 stimulations to the affected primary motor cortex using an intensity of 100% of resting motor threshold of unaffected hemisphere. Median nerve H-reflex, modified Ashworth scale (MAS) at elbow and wrist, and manual function test (MFT) were measured at baseline and after 2 weeks of treatment. RESULTS: High frequency rTMS resulted in increased H-reflex latency and decreased H-reflex amplitude and H/M ratio. Also MAS decreased and MFT score increased after 2 weeks of treatment. CONCLUSION: High frequency rTMS in the affected motor cortex might facilitate motor recovery and reduce spasticity in chronic stroke patients.

Electrophysiological Changes after Botulinum Toxin Type A in Children with Cerebral Palsy

OBJECTIVE: To investigate the electrophysiological changes after botulinum toxin type A injection in children with cerebral palsy. METHOD: Sixteen children with spastic cerebral palsy enrolled in the study. Botulinum toxin type A (Dysport(R)) was injected into gastrocnemius muscles. Electrophysiological assessments included the compound motor action potential of the tibial nerve, the sensory nerve action potential of the sural nerve, the H-reflex and the T-reflex before injection, and at 2 weeks and 4 weeks after the injection. Modified Ashworth scale was used to evaluate spasticity before, 2 weeks and 4 weeks after the injection. RESULTS: Modified Ashworth scale of the ankle decreased at 2 weeks and 4 weeks after injection. The amplitude of the H-reflex and H(max)/M(max) ratio decreased significantly at 4 weeks. The amplitude of the T-reflex decreased at 2 weeks and 4 weeks. The correlation between changes in modified Ashworth scale of the ankle and the changes in electrophysiological parameters at 4 weeks after injection were not significant. CONCLUSION: The change in T-reflex is faster than the change of H-reflex and H(max)/M(max) ratio after botulinum toxin A injection in children with cerebral palsy. Electrophysiological tests could quantify the change in spasticity after botulinum toxin injection.

Avaliação da inibição recíproca em humanos durante contrações isométricas dos músculos tibial anterior e sóleo / Assessment of reciprocal inhibition in humans during isometric contractions of the tibialis anterior and soleus muscles

Os objetivos do presente trabalho foram: (1) desenvolver um método para estimar o grau de inibição recíproca (IR) entre músculos antagonistas em humanos (sóleo e tibial anterior) e (2) comparar os níveis de IR no repouso, na dorsiflexão (DF) e na flexão plantar (FP). Participaram nove sujeitos saudáveis com idade entre 20 e 30 anos, quatro homens e cinco mulheres. Os sujeitos permaneceram sentados numa cadeira com o pé direito apoiado e fixo num pedal acoplado a um torquímetro. Foi aplicado um pulso elétrico na fossa poplítea, denominado estímulo “teste”, para se obter o reflexo H (RH) do músculo sóleo. Num segundo momento, foi aplicado um estímulo “condicionante” ao redor da cabeça da fíbula, que precedia o “teste” em 1 a 3ms. A onda H do músculo sóleo foi captada por eletrodos de superfície. O estudo foi realizado com o sujeito em repouso e realizando contração isométrica dos músculos dorsiflexores e flexores plantares do tornozelo. As amplitudes pico-a-pico dos RH controle e condicionado foram utilizadas para o cálculo da IR. Os valores de IR foram: 16,41% - 8,68 no repouso; 21,94% - 5,39 na DF e 3,12% - 11,84 na FP. Foi constatada menor inibição recíproca na FP quando comparada às demais condições (p<0,05), mas não houve aumento da IR detectável, pela metodologia aplicada...

The purposes of the present study were (1) to develop a method to estimate the level of reciprocal inhibition (RI) between antagonist muscles (soleus and anterior tibial) in humans, and (2) to compare RI levels during rest, dorsiflexion (DF) and plantarflexion (PF). Nine healthy subjects (four men, five women) aged between 20 and 30 years were assessed. Each subject remained seated with his/her right foot straped to a rigid foot plate coupled to a torquemeter. An electrical pulse (“test stimulus”) was applied to the popliteal fossa (tibial nerve) to generate an H reflex from the soleus muscle. After this control situation was tested, a “conditioning stimulus” was applied near the head of the peroneal bone, preceding by 1-3 ms the test stimulus to the tibial nerve. Each subject was tested in the three conditions RE, DF and PF. In the last two cases the subject pressed or pulled on the foot plate with a constant effort. The H reflex amplitudes were measured peak-to-peak and expressed in terms of the maximum M response. The values obtained for RI were 16,41% - 8,68 at RE; 21,94% - 5,39 in DF and 3,12% - 11,84 in PF. There was a statistically significant decrease of RI during PF when compared with the other conditions (Tukey, p<0.05) but no difference between DF compared to RE...

[Central loop versus conventional H-reflex in diabetic neuropathic patients]

Diabetes mellitus is the most prevalent endocrine disease and one of the most common causes of peripheral neuropathy. Neither conventional electrodiagnostic nor imaging studies [even MRI of lumbosacral vertebrae] can precisely differentiate concomitant radiculopathy [e.g. S[1]-root irritation] and diabetic peripheral polyneuropathy. This usually leads to unnecessary surgical interventions and its complications. In this study, S[1]-roots of diabetic neuropathic patients with impaired conventional H-reflexes were evaluated by the central loop of gastrocnemius-soleus H-reflexes. This descriptive study was performed in the clinics of Shiraz medical school in 1387[2008]. Forty two diabetic patients [14 males and 28 females with a mean age of 48.2 years] with unobtainable or abnormal conventional gastrocnemius-soleus H-reflexes and peripheral neuropathy were enrolled. The central loop of H-reflex was performed bilaterally by stimulating S[1]-root with a monopolar needle and recorded in the half way of the line from popliteal crease to the medial malleolus. Collected data were analyzed by McNemar test, using SPSS software. Of 84 limbs with impaired conventional H-reflexes, 82 limbs [97.6%] had the central loop of H-reflexes with latencies less than 8 ms. All the limbs with abnormally prolonged conventional H-reflexes' latencies had the central loop of H-reflexes' latencies in the range of 5.5-7.85 ms. The latency of central loop of H-reflex in this study was 6.34 +/- 0.96 ms with the range of 4.3-7.85 ms. In case the conventional H-reflex is impaired, the central loop of H-reflex in diabetic neuropathic patients offers a valuable approach for investigating S[1]-root. It seems that this approach leads to a better diagnosis of the absence of radiculopathy and a decrease in the rate of unnecessary surgical interventions and its complications in diabetics

Correlation between Severity of Intervertebral Disc Herniation and Electrodiagnostic Findings in the S1 Radiculopathy

OBJECTIVE: To compare the results of electrodiagnostic studies with the severity of disc herniation, measured digitally by picture archiving and communication system (PACS) from the images of magnetic resonance imaging (MRI). METHOD: MRI images were reviewed from thirty two patients who were diagnosed electrodiagnostically as unilateral S1 radiculopathy. Areas of herniated disc and spinal canal were measured and the ratio of disc herniation was calculated from the axial images stored and analyzed by PACS. The radiologic measurements were compared with the results of electrodiagnostic studies. RESULTS: The presence of abnormal spontaneous activities in needle EMG and no response in H reflex were associated with larger disc herniation (p<0.05). There was no other single electrodiagnostic study that showed correlation with any of radiologic measurements. With increasing number of abnormal electrodiagnostic tests, area of disc herniation grew larger (p<0.05). Area of spinal canal and the ratio of disc herniation did not show difference between normal and abnormal groups in most of electrodiagnostic studies. CONCLUSION: There were limited correlations between electrodiagnostic results and severity of disc herniation. The size of disc herniation, regardless of the size of spinal canal, was associated with abnormal results of electrodiagnostic tests.