scholarly journals Assessment of Hyperactive Reflexes in Patients with Spinal Cord Injury

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Dali Xu ◽  
Xin Guo ◽  
Chung-Yong Yang ◽  
Li-Qun Zhang
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Patellar Tendon ◽  
Knee Extension ◽  
Clinical Settings ◽  
Tendon Reflex ◽  
Cord Injury ◽  
Reflex Gain ◽  
Healthy Control ◽  
Tendon Reflexes

Hyperactive reflexes are commonly observed in patients with spinal cord injury (SCI) but there is a lack of convenient and quantitative characterizations. Patellar tendon reflexes were examined in nine SCI patients and ten healthy control subjects by tapping the tendon using a hand-held instrumented hammer at various knee flexion angles, and the tapping force, quadriceps EMG, and knee extension torque were measured to characterize patellar tendon reflexes quantitatively in terms of the tendon reflex gain (Gtr), contraction rate (Rc), and reflex loop time delay (td). It was found that there are significant increases inGtrandRcand decrease intdin patients with spinal cord injury as compared to the controls (P<0.05). This study presented a convenient and quantitative method to evaluate reflex excitability and muscle contraction dynamics. With proper simplifications, it can potentially be used for quantitative diagnosis and outcome evaluations of hyperreflexia in clinical settings.

scholarly journals Neuroprotective Role of Hypothermia in Acute Spinal Cord Injury

Biomedicines ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 104
Author(s):  
Hasan Al-Nashash ◽  
Angelo H. ALL
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Time Window ◽  
Clinical Settings ◽  
Neuroprotective Effects ◽  
Beneficial Effects ◽  
Cord Injury ◽  
Neuroprotective Strategy ◽  
History Of ◽  
Local Hypothermia

Even nowadays, the question of whether hypothermia can genuinely be considered therapeutic care for patients with traumatic spinal cord injury (SCI) remains unanswered. Although the mechanisms of hypothermia action are yet to be fully explored, early hypothermia for patients suffering from acute SCI has already been implemented in clinical settings. This article discusses measures for inducing various forms of hypothermia and summarizes several hypotheses describing the likelihood of hypothermia mechanisms of action. We present our objective neuro-electrophysiological results and demonstrate that early hypothermia manifests neuroprotective effects mainly during the first- and second-month post-SCI, depending on the severity of the injury, time of intervening, duration, degree, and modality of inducing hypothermia. Nevertheless, eventually, its beneficial effects gradually but consistently diminish. In addition, we report potential complications and side effects for the administration of general hypothermia with a unique referment to the local hypothermia. We also provide evidence that instead of considering early hypothermia post-SCI a therapeutic approach, it is more a neuroprotective strategy in acute and sub-acute phases of SCI that mostly delay, but not entirely avoid, the natural history of the pathophysiological events. Indeed, the most crucial rationale for inducing early hypothermia is to halt these devastating inflammatory and apoptotic events as early and as much as possible. This, in turn, creates a larger time-window of opportunity for physicians to formulate and administer a well-designed personalized treatment for patients suffering from acute traumatic SCI.

Spastic Reflexes Triggered by Ankle Load Release in Human Spinal Cord Injury

2006 ◽  
Vol 96 (6) ◽  
pp. 2941-2950 ◽  
Author(s):  
Ming Wu ◽  
Brian D. Schmit
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Human Movement ◽  
Knee Extension ◽  
Muscle Afferents ◽  
Spinal Reflex ◽  
Joint Torques ◽  
Human Spinal Cord ◽  
Cord Injury ◽  
Load Release

The rapid decrease in firing of load-sensitive group Ib muscle afferents during unloading may be particularly important in triggering the swing phase of gait. However, it still remains unclear whether load-sensitive muscle afferents modulate reflex activity in human spinal cord injury (SCI), as suggested by studies in the cat. The right hip of 12 individuals with chronic SCI was subjected to ramp (60°/s) and hold (10 s) movements over a range from 40° flexion to 0–10°extension using a custom servomotor system. An ankle dorsiflexion load was imposed and released after the hip reached a targeted position using a custom-designed pneumatic motor system. Isometric joint torques of the hip and knee, reaction torque of the ankle, and surface electromyograms (EMGs) from eight muscles of the leg were recorded following the imposed hip movement and ankle load release. Reflexes, characterized by hip flexion torque, knee extension, and coactivation of ankle flexors and extensors, were triggered by ankle load release when the hip was in an extended position. The ankle load release was observed to enhance the reflexes triggered by hip extension itself, suggesting that ankle load afferents play an important role in spastic reflexes in human SCI and that the reflex pathways associated with ankle load afferents have important implications in the spinal reflex regulation of human movement. Such muscle behaviors emphasize the role of ankle load afferents and hip proprioceptors on locomotion. This knowledge may be especially helpful in the treatment of spasms and in identifying rehabilitation strategies for producing functional movements in human SCI.

Physiological responses in males with and without spinal cord injury to recumbent synchronous versus seated asynchronous arm crank stress tests (Respuestas fisiológicas en hombres con y sin lesión medular al realizar pruebas de esfuerzo con ergómetros de

Retos ◽  
2020 ◽  
pp. 565-571
Author(s):  
Guillermo R. Oviedo ◽  
Juan Mariano Alamo ◽  
Oscar A. Niño-Mendez ◽  
Noémie Travier ◽  
Jose L. Ventura ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Physiological Responses ◽  
Clinical Settings ◽  
Stress Tests ◽  
Exercise Tests ◽  
Linear Relationships ◽  
Cord Injury ◽  
Specific Prediction ◽  
Arm Crank Ergometer

Abstract. Introduction: Maximal oxygen uptake (VO2) may be one of the most important variables in the study of the responses of people with spinal cord injury (SCI) and without SCI to physical exercise. The results achieved during its assessment serve as a diagnostic and health indicator in clinical settings. Objective: this study aimed to investigate the physiological responses in males with and without SCI performing a maximal incremental test on an asynchronous arm crank ergometer (ACr) and on a recumbent synchronous handbike ergometer (HB). Methods: ten males with SCI and 11 able-bodied males (AB group) participated in this study. Two maximal graded exercise tests were performed, starting at 10 watts and increasing the workload by 10 watts every minute until exhaustion. Results: the AB group achieved lower workloads and absolute VO2 values than the SCI group during the HB test (all p < 0.05). The submaximal values of the relative VO2 peak and RER at workloads between 40-90 watts showed significant differences between SCI and AB on HB and ACr. Significant linear relationships between workload and relative VO2 peak were found during the HB test (p < 0.001). Conclusions: these findings demonstrate that there are different physiological responses between adults with and without SCI when performing maximal and submaximal arm-ergometry. Interestingly, higher VO2 peak and workloads were achieved by the SCI group. In addition, specific prediction equations derived from the current study can be used to calculate the relative VO2 peak in handbikers with and without SCI.  Resumen. Introducción: el consumo de oxígeno (VO2) es una de las variables más importantes en el estudio de la respuesta al ejercicio en personas con y sin lesión medular (SCI; AB). Objetivo: en este estudio se analizaron las respuestas fisiológicas en hombres adultos con y sin SCI al realizar pruebas de esfuerzo máximas en un ergómetro de brazos asincrónico (ACr) en sedestación y en un ergómetro de brazos sincrónico (HB) en posición supina. Métodos: diez hombres con SCI y 11 sin SCI participaron en este estudio. Dos pruebas de esfuerzo gradual fueron realizadas por cada participante, iniciando a 10 watts e incrementando la carga 10 watts cada minuto. Resultados: el grupo sin SCI alcanzó cargas y VO2 menores que los participantes con SCI durante el test en HB (p < 0.05). Los valores submáximos para el VO2 relativo y el RER a cargas de 40-90 watts fueron estadísticamente diferentes entre los grupos en ambos tests. Se observó una correlación lineal entre las cargas de trabajo y el VO2 relativo durante el test en HB (p < 0.001). Conclusiones: los resultados obtenidos en este estudio demuestran que existen respuestas fisiológicas diferentes entre personas con y sin SCI cuando realizan pruebas de esfuerzo con cargas máximas y submáximas. Llamativamente, el grupo SCI alcanzó mayores cargas de trabajo y VO2 que los no SCI. Finalmente, se presentan dos ecuaciones específicas para obtener el VO2 de manera indirecta en personas con y sin SCI mediante el uso de un HB.

Extensor spasms triggered by imposed knee extension in chronic human spinal cord injury

2004 ◽  
Vol 162 (2) ◽  
pp. 239-249 ◽  
Author(s):  
Ming Wu ◽  
T. George Hornby ◽  
Jennifer Hilb ◽  
Brian D. Schmit
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Knee Extension ◽  
Human Spinal Cord ◽  
Cord Injury

Tendon reflexes for predicting movement recovery after acute spinal cord injury in humans

2004 ◽  
Vol 115 (10) ◽  
pp. 2350-2363 ◽  
Author(s):  
Blair Calancie ◽  
Maria R. Molano ◽  
James G. Broton
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Acute Spinal Cord Injury ◽  
Cord Injury ◽  
Tendon Reflexes

scholarly journals Cosine tuning determines plantarflexors' activities during human upright standing and is affected by incomplete spinal cord injury

2020 ◽  
Author(s):  
Kai Lon Fok ◽  
Jae W Lee ◽  
Janelle Unger ◽  
Katherine Chan ◽  
Daichi Nozaki ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Central Nervous System ◽  
Spinal Cord Injury ◽  
Nervous System ◽  
Knee Extension ◽  
Medial Gastrocnemius ◽  
Quiet Standing ◽  
Incomplete Spinal Cord Injury ◽  
Cord Injury ◽  
The Central Nervous System

Plantarflexors such as the soleus (SOL) and medial gastrocnemius (MG) play key roles in controlling bipedal stance; however, how the central nervous system controls the activation levels of these plantarflexors is not well understood. Here we investigated how the central nervous system controls the plantarflexors' activation level during quiet standing in a cosine tuning manner where the maximal activation is achieved in a preferred direction (PD). Further, we investigated how spinal cord injury affects these plantarflexors' activations. Thirteen healthy adults (AB) and thirteen individuals with chronic, incomplete spinal cord injury (iSCI) performed quiet standing trials. Their body kinematics, kinetics as well as electromyography signals from the MG and SOL were recorded. In the AB-group, we found that the plantarflexors followed the cosine tuning manner during quiet standing. That is, MG was most active when the ratio of plantarflexion torque to knee extension torque was approximately 2:-3, while SOL was most active when the ratio was approximately 2:1. This suggests that the SOL muscle despite being a monoarticular muscle is sensitive to both ankle plantarflexion and knee extension during quiet standing. The difference in the PDs accounts for the phasic activity of MG and for the tonic activity of SOL. Unlike the AB-group, the MG's activity was similar to the SOL's activity in the iSCI-group, and the SOL PDs were similar to the ones in the AB-group. This result suggests that chronic iSCI affects the control strategy, i.e., cosine tuning, for MG, which may affect standing balance in individuals with iSCI.

scholarly journals Daily Stepping in Individuals With Motor Incomplete Spinal Cord Injury

2010 ◽  
Vol 90 (2) ◽  
pp. 224-235 ◽  
Author(s):  
Poonam Saraf ◽  
Miriam R. Rafferty ◽  
Jennifer L. Moore ◽  
Jennifer H. Kahn ◽  
Kathryn Hendron ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Knee Extension ◽  
Small Sample ◽  
Substantial Contribution ◽  
Activity Limitations ◽  
Incomplete Spinal Cord Injury ◽  
Knee Extension Strength ◽  
Cord Injury ◽  
Walking Performance

BackgroundIn individuals with motor incomplete spinal cord injury (SCI), ambulatory function determined in the clinical setting is related to specific measures of body structure and function and activity limitations, although few studies have quantified the relationship of these variables with daily stepping (steps/day).ObjectiveThe aim of this study was to quantify daily stepping in ambulatory individuals with SCI and its relationship with clinical walking performance measures and specific demographics, impairments, and activity limitations.DesignA cross-sectional study was performed to estimate relationships among clinical variables to daily stepping in self-identified community versus non–community (household) walkers.MethodsAverage daily stepping was determined in 50 people with chronic, motor incomplete SCI. Data for clinical and self-report measures of walking performance also were collected, and their associations with daily stepping were analyzed using correlation and receiver operating characteristic (ROC) analyses. Relationships between daily stepping and the measures of demographics, impairments, and activity limitations were identified using correlation and regression analyses.ResultsThe ROC analyses revealed a significant discriminative ability between self-reported community and non–community walkers using clinical gait measures and daily stepping. Stepping activity generally was low throughout the sample tested, however, with an average of approximately 2,600 steps/day. Knee extension strength (force-generating capacity) and static balance were the primary variables related to daily stepping, with metabolic efficiency and capacity and balance confidence contributing to a lesser extent.LimitationsThe small sample size and use of specific impairment-related measures were potential limitations of the study.ConclusionsDaily stepping is extremely limited in individuals with incomplete SCI, with a potentially substantial contribution of impairments in knee extension strength and balance.

scholarly journals Impaired crossed facilitation of the corticospinal pathway after cervical spinal cord injury

2012 ◽  
Vol 107 (10) ◽  
pp. 2901-2911 ◽  
Author(s):  
Karen L. Bunday ◽  
Monica A. Perez
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Voluntary Contraction ◽  
Facilitatory Effect ◽  
Corticospinal Pathway ◽  
Control Subjects ◽  
Cord Injury ◽  
Healthy Control ◽  
Hand Muscle ◽  
Voluntary Contractions

In uninjured humans, it is well established that voluntary contraction of muscles on one side of the body can facilitate transmission in the contralateral corticospinal pathway. This crossed facilitatory effect may favor interlimb coordination and motor performance. Whether this aspect of corticospinal function is preserved after chronic spinal cord injury (SCI) is unknown. Here, using transcranial magnetic stimulation, we show in patients with chronic cervical SCI (C5–C8) that the size of motor evoked potentials (MEPs) in a resting intrinsic hand muscle remained unchanged during increasing levels of voluntary contraction with a contralateral distal or proximal arm muscle. In contrast, MEP size in a resting hand muscle was increased during the same motor tasks in healthy control subjects. The magnitude of voluntary electromyography was negatively correlated with MEP size after chronic cervical SCI and positively correlated in healthy control subjects. To examine the mechanisms contributing to MEP crossed facilitation we examined short-interval intracortical inhibition (SICI), interhemispheric inhibition (IHI), and motoneuronal behavior by testing F waves and cervicomedullary MEPs (CMEPs). During strong voluntary contractions SICI was unchanged after cervical SCI and decreased in healthy control subjects compared with rest. F-wave amplitude and persistence and CMEP size remained unchanged after cervical SCI and increased in healthy control subjects compared with rest. In addition, during strong voluntary contractions IHI was unchanged in cervical SCI compared with rest. Our results indicate that GABAergic intracortical circuits, interhemispheric glutamatergic projections between motor cortices, and excitability of index finger motoneurons are neural mechanisms underlying, at least in part, the lack of crossed corticospinal facilitation observed after SCI. Our data point to the spinal motoneurons as a critical site for modulating corticospinal transmission after chronic cervical SCI.

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