No abstract

Changes in reflex spinal pathways after stroke have been shown to affect motor activity in agonist and antagonist muscles acting at the same joint. However, only a few studies have evaluated the heteronymous reflex pathways modulating motoneuronal activity at different joints. This study investigates whether there are changes in the spinal facilitatory and inhibitory pathways linking knee to ankle extensors and if such changes may be related to motor deficits after stroke. The early facilitation and later inhibition of soleus H reflex evoked by the stimulation of femoral nerve at 2 times the motor threshold of the quadriceps were assessed in 15 healthy participants and on the paretic and the non-paretic sides of 15 stroke participants. The relationships between this reflex modulation and the levels of motor recovery, coordination and spasticity were then studied. Results show a significant (Mann-Whitney U; P<0.05) increase in both the peak amplitude (mean±SEM: 80±22% enhancement of the control H reflex) and duration (4.2±0.5 ms) of the facilitation on the paretic side of the stroke individuals compared to their non-paretic side (36±6% and 2.9±0.4 ms) and to the values of the control subjects (33±4% and 2.8±0.4 ms, respectively). Moreover, the later strong inhibition observed in all control subjects was decreased in the stroke subjects. Both the peak amplitude and the duration of the increased facilitation were inversely correlated (Spearman r = −0.65; P = 0.009 and r = −0.67; P = 0.007, respectively) with the level of coordination (LEMOCOT) of the paretic leg. Duration of this facilitation was also correlated (r = −0.58, P = 0.024) with the level of motor recovery (CMSA). These results confirm changes in transmission in heteronymous spinal pathways that are related to motor deficits after stroke.

BackgroundAbnormal coactivation of leg extensors is often observed on the paretic side of stroke patients while they attempt to move. The mechanisms underlying this coactivation are not well understood. This study (1) compares the coactivation of leg extensors during static contractions in stroke and healthy individuals, and (2) assesses whether this coactivation is related to changes in intersegmental pathways between quadriceps and soleus (Sol) muscles after stroke.MethodsThirteen stroke patients and ten healthy individuals participated in the study. Levels of coactivation of knee extensors and ankle extensors were measured in sitting position, during two tasks: maximal isometric voluntary contractions in knee extension and in plantarflexion. The early facilitation and later inhibition of soleus voluntary EMG evoked by femoral nerve stimulation were assessed in the paretic leg of stroke participants and in one leg of healthy participants.ResultsCoactivation levels of ankle extensors (mean ± SEM: 56 ± 7% of Sol EMG max) and of knee extensors (52 ± 10% of vastus lateralis (VL) EMG max) during the knee extension and the ankle extension tasks respectively were significantly higher in the paretic leg of stroke participants than in healthy participants (26 ± 5% of Sol EMG max and 10 ± 3% of VL EMG max, respectively). Early heteronymous facilitation of Sol voluntary EMG in stroke participants (340 ± 62% of Sol unconditioned EMG) was significantly higher than in healthy participants (98 ± 34%). The later inhibition observed in all control participants was decreased in the paretic leg. Levels of coactivation of ankle extensors during the knee extension task were significantly correlated with both the increased facilitation (Pearson r = 0.59) and the reduced inhibition (r = 0.56) in the paretic leg. Measures of motor impairment were more consistently correlated with the levels of coactivation of biarticular muscles than those of monoarticular muscles.ConclusionThese results suggest that the heteronymous pathways linking quadriceps to soleus may participate in the abnormal coactivation of knee and ankle extensors on the paretic side of stroke patients. The motor impairment of the paretic leg is strongly associated with the abnormal coactivation of biarticular muscles.

BackgroundExtensor synergy is often observed in the paretic leg of stroke patients. Extensor synergy consists of an abnormal stereotyped co-activation of the leg extensors as patients attempt to move. As a component of this synergy, the simultaneous activation of knee and ankle extensors in the paretic leg during stance often affects gait pattern after stroke. The mechanisms involved in extensor synergy are still unclear. The first objective of this study is to compare the co-activation of knee and ankle extensors during the stance phase of gait between stroke and healthy individuals. The second objective is to explore whether this co-activation is related to changes in heteronymous spinal modulations between quadriceps and soleus muscles on the paretic side in post-stroke individuals.MethodsThirteen stroke patients and ten healthy individuals participated in gait and heteronymous spinal modulation evaluations. Co-activation was measured using peak EMG activation intervals (PAI) and co-activation amplitude indexes (CAI) between knee and ankle extensors during the stance phase of gait in both groups. The evaluation of heteronymous spinal modulations was performed on the paretic leg in stroke participants and on one leg in healthy participants. This evaluation involved assessing the early facilitation and later inhibition of soleus voluntary EMG induced by femoral nerve stimulation.ResultsAll PAI were lower and most CAI were higher on the paretic side of stroke participants compared with the co-activation indexes among control participants. CAI and PAI were moderately correlated with increased heteronymous facilitation of soleus on the paretic side in stroke individuals.ConclusionsIncreased co-activation of knee and ankle extensors during gait is related to changes in intersegmental facilitative pathways linking quadriceps to soleus on the paretic side in stroke individuals. Malfunction of intersegmental pathways could contribute to abnormal timing of leg extensors during the stance phase of gait in hemiparetic individuals.Electronic supplementary materialThe online version of this article (doi:10.1186/1743-0003-11-148) contains supplementary material, which is available to authorized users.

Introdução: A fisioterapia atua na reabilitação de pacientes com amputação transtibial, como também pode intervir na prevenção e tratamento das complicações decorrentes da amputação. Objetivo: Investigar a intervenção da fisioterapia em pacientes com amputação transtibial. Métodos: Foi realizada uma revisão sistemática da literatura, consultando as bases de dados: PubMed, CINAHL, EMBASE, SPORTDiscus, PEDro, LILACS e SciELO. Utilizaram-se os descritores “amputação” e “transtibial” combinados com os descritores “fisioterapia” ou “terapia física”. A busca foi realizada na segunda quinzena de fevereiro de 2013. Foram incluídos ensaios clínicos controlados e randomizados, sem restrição de idioma ou período de publicação, que versavam sobre a intervenção fisioterapêutica em pacientes com amputação transtibial. Para avaliação da qualidade metodológica dos estudos foram utilizadas a Escala de Qualidade de Jadad e a Escala PEDro. Resultados: Pela estratégia de busca retornaram 23 artigos, dos quais três foram incluídos na revisão. Um utilizou a técnica de aprendizagem sem erros para a colocação da prótese, outro investigou os efeitos de um programa de treinamento de força e o terceiro comparou os efeitos da aplicação da bandagem convencional e a fisioterapia descongestiva na redução do edema no pós-operatório. Somente um estudo foi considerado de alta ou boa qualidade metodológica pelas Escala PEDro e Jadad, os outros dois estudos foram classificados de baixa qualidade metodológica pelas duas escalas. Conclusões: Observou-se evidência limitada para as modalidades de fisioterapia utilizadas.

Patellar tendon vibration can reduce the facilitation between knee and ankle extensors, which suggests effective presynaptic inhibition but decreased post-activation depression in the lower limb of people after chronic hemiparetic stroke. Further studies are warranted to determine whether such vibration could be used to reduce the abnormal extension synergy of knee and ankle extensors in people after hemiparetic stroke.

Background. Muscle vibration has been shown to increase the corticospinal excitability assessed by transcranial magnetic stimulation (TMS) and to change voluntary force production in healthy subjects. Objectives. To evaluate the effect of vibration on corticospinal excitability using TMS and on maximal motor output using maximal voluntary contraction (MVC) in individuals with chronic hemiparesis. Methodology. Nineteen hemiparetic and 17 healthy control subjects participated in this study. Motor evoked potentials (MEPs) and MVC during lateral pinch grip were recorded at first dorsal interosseous muscle in a single session before, during, and after one-minute trials of 80 Hz vibration of the thenar eminence. Results. In hemiparetic subjects, vibration increased MEP amplitudes to a level comparable to that of control subjects and triggered a MEP response in 4 of 7 patients who did not have a MEP at rest. Also, vibration increased the maximal rate of force production (d /d max ) in both control and hemiparetic subjects but it did not increase MVC. Conclusion. Motor response generated with a descending cortical drive in chronic hemiparetic subjects can be increased during vibration. Vibration could be used when additional input is needed to reveal motor responses and to increase rate of force generation.

The aim of this study was to analyze the immediate effects of a manipulative intervention in chronic nonspecific low back pain and in the increase of global joint mobility. This  cross-sectional, randomized and single-blind study, was composed by 19 women with 18 to 55 years, divided into two groups: experimental group (EG = 10) and control group (CG = 9). The evaluation consisted of a physical examination, Rolland Morris’s questionnaire,  "distance fingers-floor" test, Visual Analogue Scale and algometry (spinous process L5) before and after the manipulative intervention. The EG volunteers   underwent five vertebral manipulations: two in the pelvis (bilateral), one on the middle thoracic (T5-T7) and two in the neck (C3 bilateral). The volunteers of the CG were submitted to two placebos manipulative techniques. They lying in the right and left lateral decubitus for 10 seconds each, the same position of global manipulation in the pelvis, but without performing the manipulative impulse (thrust). The results were statistically significant to reduce pain (p <0.001) and increase global joint mobility (p <0.05) when comparing the pre and post intragroups. However, no statistic difference was observed in the pain threshold. We conclude that a manipulative intervention can reduce pain and increase global joint mobility immediately after the spinal manipulation.