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.

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.

H-reflex in the diagnosis of lumbosacral radiculopathy

This work comprised fifteen patients suspected of having unilateral fifth lumbar root [L[5]] and/or first sacral root [S[1]] radiculopathy secondary to spinal nerve compression. Ten healthy subjects matched in age, sex and height served as controls. Diagnosis was confirmed clinically and with radiographic assessment. H-reflex was done bilaterally to both symptomatic and asymptomatic sides from both soleus and gastrocneumius muscles according to Shahani [1986]. Peak to peak amplitude and latency was recorded. On the symptomatic side a significant prolongation was found in the latency of the H-reflex as elicited from both soleus and gastrocneumius muscles on the symptomatic side of patients versus the asymptomatic side or the control group p<0.05. There was a highly significant reduction p<0.001 of the amplitude of the motor evoked response from both muscles as well. However, abnormal H-reflex was also encountered in the non-symptomatic side. The H-reflex recorded from the soleus was more sensitive than from the gastrocnemius muscle. All patients with neurological deficit showed prolonged latency and reduced amplitude. Both techniques, measuring H-reflex from soleus or gastrocnemius are complementary to each other and the positive results of any of them could be enough for the diagnosis of radiculopathy

Valor diagnóstico del reflejo H en síndrome de compresión medular y/o radicular cervical / Diagnostic value of the H-reflex in the syndrome of radicular compression

Los problemas radiculo-medulares de etiología diversa que afectan a nivel cervical, constituyen en la edad adulta un motivo frecuente de consulta. Los estudios electrofisiológicos son de importante valor diagnóstico, en la evaluación de éstas etiologías. El objetivo del presente trabajo fue evaluar la utilidad diagnóstica del reflejo H (RH) en pacientes con síndrome de compresión medular y/o radicular a nivel cervical en un estudio observacional, transversal, prospectivo y comparativo. Se estudiaron de junio a noviembre de 1996 en el Instituto Nacional de Neurología y Neurocirugía nueve pacientes, cuatro masculinos y cinco femeninos, con rango de edad de 26 a 72 años y promedio de 42.7 ñ 14.9 años, se excluyeron aquellos con cirugías previas de columna cervical, neuropatía periférica o enfermedad de motoneurona de asta anterior. Los parámetros evaluados del RH fueron su latencia, amplitud y diferencia lado a lado en latencia y su comparación lado a lado tienen mayor valor clínico que la amplitud como parámetros de anormalidad. Al realizar la comparación de los resultados del RH con los estudios de imagen se observó que existe alta correlación (r = 0.83)

A study of peripheral nerve function in neonates and infants.

Motor and sensory nerve conduction velocity, H-reflex and F-response have been studied in the age group showing maximum changes i.e. neonates and infants. The nerve conduction velocity in upper and lower limbs was 25 M/S and 23.75 M/S respectively in neonate age group; 34.4 M/S and 32.4 M/S respectively in infant group. A significant relationship of age with nerve conduction parameters (velocity, terminal latency) has been observed in infants group but not so in neonate group. H-reflex (late response) was elicited in both Abductor Pollicis Brevis and Soleus. It was present in small muscles of hand (i.e. APB) in all the neonates and 55% of the infants only. This could be attributed to immaturity of nervous system. However, in the lower limb, H-reflex could be elicited in 100% of infants and neonates. In the present study, the relationship of age and height with different nerve conduction parameters as well as H-reflex (latency) has been highlighted.

Motor nerve conduction velocity & Hoffman's reflex latency in newborns.

A total of 72 newborns and their mothers were studied to assess the influence of various variables on the motor nerve conduction velocity (MNCV) and Hoffman's reflex latency (H-RL) of the babies with a view to differentiate fullterm and preterm low birth weight babies. MNCV were significantly lower and H-RL significantly higher in preterm appropriate for gestational (PT-AGA) age babies compared to fullterm appropriate for gestational age (FT-AGA) and fullterm intrauterine growth retarded babies (FT-IUGR). In FT-IUGR babies, only MNCV was significantly reduced as compared to FT-AGA babies.

Estudio normativo del reflejo H: valor diagnóstico en el síndrome comprensivo radicular de S1 / Standard study of H reflex: diagnostic value in the radicular compression syndrome of S1

Se realizó el reflejo H en una muestra de 78 pacientes con diagnóstico clínico de síndrome comprensivo radicular lumbosacro según los criterios descritos en la literatura médica. los cuales no se ajustaban a nuestra población. por lo que se realizó una nueva norma del reflejo H en un grupo de 39 sujetos normales a partir del cual se hallaron nuevos criterios, los que se aplicaron a la muestra inicial. Estos valores permitieron diferenciar los grupos analizados de acuerdo con la posible raíz comprometida. Para validar los nuevos criterios, éstos se estudiaron en 32 pacientes con diagnóstico quirúrgico de hernia discal y se comprobó el 96,8 % de confiabilidad. Se concluye que el reflejo H es útil en el diagnóstico de radiculopatía 1 y debe ser utilizado junto con el electromiograma, ante la sospecha de compresión L5 y S1 para diferenciar ambas raíces vecinas

Avaliaçäo eletrofisiológica das radiculopatias / Electrophysiologyc evaluation of radiculopathies

O autor apresenta uma atualizaçäo no diagnóstico eletrofisiológico das radiculopatias. Revisa informaçöes anatômicas, clínicas e sobre as técnicas comumente utilizados de Eletroneuromiografia, Reflexo H, Resposta F e Potenciais Evocados Somatosensitivos no diagnóstico destas patologias. Finalmente, enfatiza a importância destas técnicas na avaliaçäo funcional e no prognóstico das disfunçöes radiculares

Effect of altered ventilations on human spinal and supra spinal reflexes.

The present study was aimed at evaluating the alterations in the human reflexes brought about by briefly altered ventilations. In 20 healthy young male volunteers, the H reflex and blink reflex were studied during normal ventilation, voluntary hypoventilation and voluntary hyperventilation. The latencies of these reflexes were compared. It was observed that the amount of altered ventilations used in the present study could not produce any significant change in these reflexes except in the case of the early response of the blink reflex.