Matheus Joner Wiest

H-REFLEXES REDUCE FATIGUE OF EVOKED CONTRACTIONS AFTER SPINAL CORD INJURY

Introduction: Neuromuscular electrical stimulation (NMES) over a muscle belly (mNMES) generates contractions predominantly through M‐waves, while NMES over a nerve trunk (nNMES) can generate contractions through H‐reflexes in people who are neurologically intact. We tested whether the differences between mNMES and nNMES are present in people with chronic motor‐complete spinal cord injury and, if so, whether they influence contraction fatigue. Methods: Plantar‐flexion torque and soleus electromyography were recorded from 8 participants. Fatigue protocols were delivered using mNMES and nNMES on separate days. Results: nNMES generated contractions that fatigued less than mNMES. Torque decreased the least when nNMES generated contractions, at least partly through H‐reflexes (n = 4 participants; 39% decrease), and torque decreased the most when contractions were generated through M‐waves, regardless of NMES site (nNMES 71% decrease, n = 4; mNMES, 73% decrease, n = 8). Conclusions: nNMES generates contractions that fatigue less than mNMES, but only when H‐reflexes contribute to the evoked contractions. Muscle Nerve 50:224–234, 2014

Efeito da equoterapia na estabilidade postural de portadores de esclerose múltipla: estudo preliminar

OBJETIVO: El objetivo de este estudio fue identificar los efectos de la hipoterapia sobre el control postural en pacientes con esclerosis multiple (EM). METODO: Hicieron parte de este estudio 11 portadores de EM divididos en Grupo Intervencion (GI) y Grupo Control (GC). El GI fue insertado en un programa de hipoterapia durante cuatro meses, siendo realizadas dos sesiones semanales con duracion de 50 minutos cada una. La estabilidad postural fue evaluada utilizando una plataforma de fuerza (para calcular el desplazamiento del centro de presion (COP), durante 30 segundos en postura erecta casi-estatica, con ojos abiertos y cerrados, antes y despues del entrenamiento con hipoterapia. El tratamiento estadistico fue realizado a traves de ANOVA y Post hoc de Tukey con p<0,05. RESULTADOS: la amplitud de oscilacion antero-posterior se redujo significativamente en el GI despues de la estimulacion, mientras que el GC mantuvo un comportamiento sin cambios entre las evaluaciones. En ambos grupos la estabilidad postural fue reducida con la supresion de la informacion visual. CONCLUSIONES: la adaptacion funcional proporcionada por la hipoterapia fue capaz de mejorar la estabilidad postural de los portadores de EM. Los resultados corroboran la literatura que soporta el uso de la hipoterapia como una potencial intervencion en los desordenes del control postural en portadores de EM.OBJECTIVE: This study intended to identify the effects of hippotherapy on the postural control of multiple sclerosis (MS) patients. METHODS: Eleven MS patients were separated into two groups: Intervention Group (IG) and Control Group (CG). Hippotherapy consisted of two 50-minute sessions each week for four months. Postural stability was evaluated before and after hippotherapy using a force plate to calculate the center of pressure (COP), when subjects stood still for 30 seconds, with eyes open and closed. Statistical analysis was performed by ANOVA and post hoc Tukey tests, p<0.05. RESULTS: Hippotherapy significantly reduced the amplitude of oscillation in the anteroposterior direction in IG while CG remained unaltered. In both groups postural stability was reduced after the suppression of visual information. CONCLUSIONS: Hippotherapy induced functional adaptations that resulted in better postural stability of subjects with MS. This study corroborates literature supporting the use of hippotherapy as a possible intervention for balance disorders in patients with MS.

Interleaved neuromuscular electrical stimulation: Motor unit recruitment overlap.

Introduction: In this study, we quantified the “overlap” between motor units recruited by single pulses of neuromuscular electrical stimulation (NMES) delivered over the tibialis anterior muscle (mNMES) and the common peroneal nerve (nNMES). We then quantified the torque produced when pulses were alternated between the mNMES and nNMES sites at 40 Hz (“interleaved” NMES; iNMES). Methods: Overlap was assessed by comparing torque produced by twitches evoked by mNMES, nNMES, and both delivered together, over a range of stimulus intensities. Trains of iNMES were delivered at the intensity that produced the lowest overlap. Results: Overlap was lowest (5%) when twitches evoked by both mNMES and nNMES produced 10% peak twitch torque. iNMES delivered at this intensity generated 25% of maximal voluntary dorsiflexion torque (11 Nm). Discussion: Low intensity iNMES leads to low overlap and produces torque that is functionally relevant to evoke dorsiflexion during walking. Muscle Nerve 55: 490–499, 2017

Análise da estabilidade postural e propriocepção de idosas fisicamente ativas

Introduction The thresholds for cutaneous and proprioceptive sensations are mechanisms that may be affected during aging resulting in reduced postural stability. Objective Verify proprioception and postural stability in physically active elderly women and verify the correlation between these variables. Materials and methods The study group consisted of twenty-five 70.2 ± 6.9 year-old women that practiced hydrogymnastics at moderate intensity for at least three months and two hours per week. Proprioception was tested using an analogic goniometer firmly attached to the knee joint of the preferred lower limb of the subject. The subjects needed to reproduce the knee angles that were first demonstrated passively. The difference between the angles found in each condition (passive x voluntary) was calculated. Postural stability was analyzed using a force platform at the ground level. Using the force data obtained by the force plate the center of pressure (CP) was calculated. Subjects were compared while in a bipedal posture, with their eyes opened (EO) and closed (EC). Data was analyzed using Spermann correlation and Mann-Whitney test, with a significance level of 5%. Results No statistically significant difference was found between EO and EC conditions. Proprioception revealed a positive correlation (R = 0.551; p = 0.004) with age and postural stability in the conditions of EO and EC, showing larger amplitudes and velocities of CP displacement (p < 0.05). Conclusion Our results suggested that functional losses induced by aging reduces the efficiency of the proprioception system and postural stability.

Effect of hippotherapy on the postural stability of patients with multiple sclerosis: a preliminary study

OBJETIVO: El objetivo de este estudio fue identificar los efectos de la hipoterapia sobre el control postural en pacientes con esclerosis multiple (EM). METODO: Hicieron parte de este estudio 11 portadores de EM divididos en Grupo Intervencion (GI) y Grupo Control (GC). El GI fue insertado en un programa de hipoterapia durante cuatro meses, siendo realizadas dos sesiones semanales con duracion de 50 minutos cada una. La estabilidad postural fue evaluada utilizando una plataforma de fuerza (para calcular el desplazamiento del centro de presion (COP), durante 30 segundos en postura erecta casi-estatica, con ojos abiertos y cerrados, antes y despues del entrenamiento con hipoterapia. El tratamiento estadistico fue realizado a traves de ANOVA y Post hoc de Tukey con p<0,05. RESULTADOS: la amplitud de oscilacion antero-posterior se redujo significativamente en el GI despues de la estimulacion, mientras que el GC mantuvo un comportamiento sin cambios entre las evaluaciones. En ambos grupos la estabilidad postural fue reducida con la supresion de la informacion visual. CONCLUSIONES: la adaptacion funcional proporcionada por la hipoterapia fue capaz de mejorar la estabilidad postural de los portadores de EM. Los resultados corroboran la literatura que soporta el uso de la hipoterapia como una potencial intervencion en los desordenes del control postural en portadores de EM.OBJECTIVE: This study intended to identify the effects of hippotherapy on the postural control of multiple sclerosis (MS) patients. METHODS: Eleven MS patients were separated into two groups: Intervention Group (IG) and Control Group (CG). Hippotherapy consisted of two 50-minute sessions each week for four months. Postural stability was evaluated before and after hippotherapy using a force plate to calculate the center of pressure (COP), when subjects stood still for 30 seconds, with eyes open and closed. Statistical analysis was performed by ANOVA and post hoc Tukey tests, p<0.05. RESULTS: Hippotherapy significantly reduced the amplitude of oscillation in the anteroposterior direction in IG while CG remained unaltered. In both groups postural stability was reduced after the suppression of visual information. CONCLUSIONS: Hippotherapy induced functional adaptations that resulted in better postural stability of subjects with MS. This study corroborates literature supporting the use of hippotherapy as a possible intervention for balance disorders in patients with MS.

Interleaved neuromuscular electrical stimulation after spinal cord injury.

Neuromuscular electrical stimulation (NMES) over a muscle belly (mNMES) recruits superficial motor units (MUs) preferentially, whereas NMES over a nerve trunk (nNMES) recruits MUs evenly throughout the muscle. We performed tests to determine whether “interleaving” pulses between the mNMES and nNMES sites (iNMES) reduces the fatigability of contractions for people experiencing paralysis because of chronic spinal cord injury.

Utilizing Physiological Principles of Motor Unit Recruitment to Reduce Fatigability of Electrically-Evoked Contractions: A Narrative Review

Neuromuscular electrical stimulation (NMES) is used to produce contractions to restore movement and reduce secondary complications for individuals experiencing motor impairment. NMES is conventionally delivered through a single pair of electrodes over a muscle belly or nerve trunk using short pulse durations and frequencies between 20 and 40Hz (conventional NMES). Unfortunately, the benefits and widespread use of conventional NMES are limited by contraction fatigability, which is in large part because of the nonphysiological way that contractions are generated. This review provides a summary of approaches designed to reduce fatigability during NMES, by using physiological principles that help minimize fatigability of voluntary contractions. First, relevant principles of the recruitment and discharge of motor units (MUs) inherent to voluntary contractions and conventional NMES are introduced, and the main mechanisms of fatigability for each contraction type are briefly discussed. A variety of NMES approaches are then described that were designed to reduce fatigability by generating contractions that more closely mimic voluntary contractions. These approaches include altering stimulation parameters, to recruit MUs in their physiological order, and stimulating through multiple electrodes, to reduce MU discharge rates. Although each approach has unique advantages and disadvantages, approaches that minimize MU discharge rates hold the most promise for imminent translation into rehabilitation practice. The way that NMES is currently delivered limits its utility as a rehabilitative tool. Reducing fatigability by delivering NMES in ways that better mimic voluntary contractions holds promise for optimizing the benefits and widespread use of NMES-based programs.

Efecto de la hipoterapia en la estabilidad postural de portadores de esclerosis múltiple: estudio preliminar

OBJETIVO: El objetivo de este estudio fue identificar los efectos de la hipoterapia sobre el control postural en pacientes con esclerosis multiple (EM). METODO: Hicieron parte de este estudio 11 portadores de EM divididos en Grupo Intervencion (GI) y Grupo Control (GC). El GI fue insertado en un programa de hipoterapia durante cuatro meses, siendo realizadas dos sesiones semanales con duracion de 50 minutos cada una. La estabilidad postural fue evaluada utilizando una plataforma de fuerza (para calcular el desplazamiento del centro de presion (COP), durante 30 segundos en postura erecta casi-estatica, con ojos abiertos y cerrados, antes y despues del entrenamiento con hipoterapia. El tratamiento estadistico fue realizado a traves de ANOVA y Post hoc de Tukey con p<0,05. RESULTADOS: la amplitud de oscilacion antero-posterior se redujo significativamente en el GI despues de la estimulacion, mientras que el GC mantuvo un comportamiento sin cambios entre las evaluaciones. En ambos grupos la estabilidad postural fue reducida con la supresion de la informacion visual. CONCLUSIONES: la adaptacion funcional proporcionada por la hipoterapia fue capaz de mejorar la estabilidad postural de los portadores de EM. Los resultados corroboran la literatura que soporta el uso de la hipoterapia como una potencial intervencion en los desordenes del control postural en portadores de EM.OBJECTIVE: This study intended to identify the effects of hippotherapy on the postural control of multiple sclerosis (MS) patients. METHODS: Eleven MS patients were separated into two groups: Intervention Group (IG) and Control Group (CG). Hippotherapy consisted of two 50-minute sessions each week for four months. Postural stability was evaluated before and after hippotherapy using a force plate to calculate the center of pressure (COP), when subjects stood still for 30 seconds, with eyes open and closed. Statistical analysis was performed by ANOVA and post hoc Tukey tests, p<0.05. RESULTS: Hippotherapy significantly reduced the amplitude of oscillation in the anteroposterior direction in IG while CG remained unaltered. In both groups postural stability was reduced after the suppression of visual information. CONCLUSIONS: Hippotherapy induced functional adaptations that resulted in better postural stability of subjects with MS. This study corroborates literature supporting the use of hippotherapy as a possible intervention for balance disorders in patients with MS.