重复经颅磁刺激治疗脊髓损伤的临床疗效

目的：观察重复经颅磁刺激（rTMS）治疗对脊髓损伤（SCI）的临床疗效。方法：对26例SCI患者进行rTMS治疗,并与20例健康志愿者对照分析,观察治疗前后运动诱发电位（MEP）波幅及潜伏期的变化。结果：26例SCI患者治疗前MEP潜伏期延迟,波幅降低,治疗后均有明显变化,表现为MEP潜伏期明显缩短,波幅明显增高,治疗前后比较,差异有统计学意义。结论：rTMS治疗SCI具有一定疗效。     

Transcranial magnetic stimulation: Cortical motor maps in acute spinal cord injury

Summary This investigation examined the motor pathways of four, C5-6 spinal cord injured (SCI) patients within 6–17 days of injury. Mapping of the motor cortex was achieved by transcranial magnetic stimulation (TMS) applied to the scalp. Motor evoked potentials were recorded from target muscle groups (Biceps brachii and Abductor pollicis brevis m.). Evidence of an expanded cortical map of the preserved contralateral biceps muscle was demonstrated in these patients as early as 6 days. These findings suggested that early motor re-organization may occur following acute cervical spinal cord injury in man.     

Musculoskeletal plasticity after acute spinal cord injury: effects of long-term neuromuscular electrical stimulation training

Maintaining the physiologic integrity of paralyzed limbs may be critical for those with spinal cord injury (SCI) to be viable candidates for a future cure. No long-term intervention has been tested to attempt to prevent the severe musculoskeletal deterioration that occurs after SCI. The purposes of this study were to determine whether a long-term neuromuscular electrical stimulation training program can preserve the physiological properties of the plantar flexor muscles (peak torque, fatigue index, torque-time integral, and contractile speed) as well as influence distal tibia trabecular bone mineral density (BMD). Subjects began unilateral plantar flexion electrical stimulation training within 6 wk after SCI while the untrained leg served as a control. Mean compliance for the 2-yr training program was 83%. Mean estimated compressive loads delivered to the tibia were approximately 1-1.5 times body weight. The training protocol yielded significant trained versus untrained limb differences for torque (+24%), torque-time integral (+27%), fatigue index (+50%), torque rise time (+45%), and between-twitch fusion (+15%). These between-limb differences were even greater when measured at the end of a repetitive stimulation protocol (125 contractions). Peripheral quantitative computed tomography revealed 31% higher distal tibia trabecular BMD in trained limbs than in untrained limbs. The intervention used in this study was sufficient to limit many of the deleterious muscular and skeletal adaptations that normally occur after SCI. Importantly, this method of load delivery was feasible and may serve as the basis for an intervention to preserve the musculoskeletal properties of individuals with SCI.     

Human and rat skeletal muscle adaptations to spinal cord injury.

Results of studies of rodent skeletal muscle plasticity are often extrapolated to humans. However, responses to "disuse" may be species specific, in part because of different inherent properties of anatomically similar muscles. Thus, this study quantified human and rat m. vastus lateralis (VL) fiber adaptations to 11 weeks of spinal cord injury (SCI). The m. VL was taken from 8 young (54 d) male Charles River rats after T-9 laminectomy (n = 4) or sham surgery (n = 4). In addition, the m. VL was biopsied in 7 able-bodied and in 7 SCI humans (31.3 +/- 4.7 years, mean +/- SE). Samples were sectioned and fibers were analyzed for type (I, IIa, IIb/x), cross-sectional area (CSA), succinate dehydrogenase (SDH), alpha-glycerol-phosphate dehydrogenase (GPDH), and actomyosin adenosine triphosphatase (qATPase) activities. Rat fibers had 1.5- to 2-fold greater SDH and GPDH activities while their fibers were 60% the size of those in humans. The most striking differences, however, were the absence of slow fibers in the rat and its four-fold greater proportion of IIb/x fibers (80% vs. 16% of the CSA) compared to humans. SCI decreased SDH activity more in rats whereas atrophy and IIa to IIb/x fiber shift occurred to a greater extent in humans. It is suggested that the rat is a reasonable model for studying the predominant response to SCI, atrophy. However, its high proportion of IIb/x fibers limits evaluation of the mechanical consequences of shifting to "faster" contractile machinery after SCI.     

Changes in muscle T 2 relaxation properties following spinal cord injury and locomotor training

Magnetic resonance (MR) is frequently used to study structural and biochemical properties of skeletal muscle. Changes in proton transverse relaxation (T ₂) properties have been used to study muscle cellular damage, as well as muscle activation during exercise protocols. In this study, we implemented MR imaging to characterize the T ₂ relaxation properties of rat hindlimb muscles following spinal cord injury (SCI) and locomotor training. After moderate midthoracic contusion SCI, Sprague–Dawley rats were assigned to either treadmill training, cycle training or an untrained group. T ₂ weighted images were obtained and mean muscle T ₂ times were calculated in the tibialis anterior, soleus, and gastrocnemius (GAS) muscles at pre-injury as well as at 1, 2, 4, 8, and 12 weeks post-injury. Following SCI, hindlimb muscles in untrained animals showed a significant increase in muscle T ₂, with the most dramatic shift (+5.46 ms) observed in soleus muscle at 1 week post-SCI. Subsequently, all muscle groups showed a spontaneous recovery in muscle T ₂ with normalized T ₂ values in the GAS and tibilias anterior muscles at 4 weeks and the soleus at 12 weeks post-SCI. Both training paradigms, treadmill and cycling training, accelerated the recovery of soleus muscle T ₂. As a result, soleus muscle T ₂ recovered back to pre-injury values within 3 weeks of training in both training groups. Finally, in vitro histological assessments of rat skeletal muscles demonstrated that there was no apparent muscle injury in any of the muscles studied at 1 week post-SCI.     

磁刺激在脊髓损伤康复治疗中的应用进展

磁刺激在脊髓等中枢神经系统损伤疾病的康复治疗中得到了广泛应用,磁刺激作用于不同部位以及不同的治疗频率,将产生不同的治疗效果。本文综述近年来有关磁刺激治疗在脊髓损伤后运动功能障碍、神经病理性疼痛、肌张力增高、神经源性膀胱、直肠功能等方面的治疗文献,以期为临床治疗提供相关依据。     

Determining appropriate models for joint control using surface electrical stimulation of soleus in spinal cord injury

The mechanical impedance of the ankle joint during electrical stimulation of the soleus is studied by applying constant-velocity 10° angular perturbations to the ankle and measuring the resultant torque. Both neurologically intact subjects and spinal cord injured subjects are tested. Lumped, piecewise linear models are developed to predict the torque from the measured displacement and acceleration signals. The commonly used second-order mass-spring-dashpot model fails to predict the changes in torque that occur following imposed movements. A fiveelement, directionally-dependent piecewise linear model is much better at predicting the measured responses for velocities up to 50° s⁻¹. Numerical least squared error indentification techniques are used to estimate the model parameters for three neurologically intact and three spinal cord injured subjects. The average error between the model’s response and the measured response across all subjects is 10·9%. There is some evidence that a velocity-dependent non-linear model could produce better results than the directionally-dependent piecewise linear model.     

Control of standing balance at leaning postures with functional neuromuscular stimulation following spinal cord injury

This study systematically explored the potential of applying feedback control of functional neuromuscular stimulation (FNS) for stabilizing various erect and leaning standing postures after spinal cord injury (SCI). Perturbations ranging from 2 to 6% body weight were applied to two subjects with motor complete thoracic level SCI who were proficient at standing with implanted multichannel neural stimulators to activate the ankle, knee, hip and trunk muscles. The subjects stood with four different postures: erect, forward, forward-right and forward-left. Repeatable and controlled perturbations were applied in the forward, backward, rightward and leftward directions by linear actuators pulling on ropes attached to the subjects via a belt worn just above the waist. Upper extremity (UE) forces exerted on a stationary walker were measured with load cells attached to the handles. A feedback controller based on center of pressure (CoP) varied the stimulation levels to the otherwise paralyzed muscles so as to resist the effects of the perturbations. The effect of the feedback controller was compared to the case where only open-loop baseline stimulation was applied. This was done in terms of: (a) maximum resultant UE force exerted by the subjects on the walker, (b) maximum resultant CoP overshoot and (c) CoP root-mean-square deviation (RMSD). Feedback control resulted in significant reductions in the mean values of the majority of outcome values compared to baseline open-loop stimulation. Maximum resultant UE force was reduced by as much as 50% in one of the postures for one of the subjects. RMSD and maximum CoPs were reduced by as much as 75 and 70%, respectively, with feedback control. These results indicate that feedback control can be used to reject destabilizing disturbances in individuals with SCI using FNS not only for erect postures but also for leaning postures typically adopted during reaching while attempting various activities of daily living.     

Mitochondrial health and muscle plasticity after spinal cord injury

European Journal of Applied Physiology - Mitochondria are responsible for aerobic respiration and large-scale ATP production in almost all cells of the body. Their function is decreased in many...     

Functional electrical stimulation for the upper limb in tetraplegic spinal cord injury: a systematic review

Abstract

Technological advances have helped to improve functional ability in spinal cord injury survivors. The aim of this study is to systematically review the evidence for functional electrical stimulation (FES) on functional tasks involving the upper limb in people with spinal cord injuries. The authors systematically searched from September 2009 to September 2014 in relevant databases using a combination of keywords covering spinal cord injury and FES. Studies were selected using pre-determined criteria. The search yielded 144 studies. Only five studies met the inclusion criteria. All five reported improvements immediately and at follow-up in functional ability as a result of FES or FES combined with conventional therapy. There is some preliminary evidence that FES may reduce disability due to upper limb-related activity limitations in tetraplegic spinal cord injury. Further work needs to examine the role of FES in more detail and in combination with other treatments.     

Graded unilateral cervical spinal cord injury and respiratory motor recovery

We examined the potential contribution of ventromedial (VM) tissue sparing to respiratory recovery following chronic (1 mo) unilateral C2 spinal cord injury (SCI) in rats. Preserved white matter ipsilateral to the injury was quantitatively expressed relative to contralateral white matter. The ipsilateral-to-contralateral white matter ratio was 0 after complete C2 hemisection (C2HS) and 0.23 ± 0.04 with minimal VM sparing. Inspiratory (breath min⁻¹) and phrenic frequency (burst min⁻¹), measured by plethysmography (conscious rats) and phrenic neurograms (anesthetized rats) respectively, were both lower with minimal VM sparing (p < 0.05 vs. C2HS). Tidal volume also was greater in minimal VM sparing rats during a hypercapnic challenge (p < 0.05 vs. C2HS). In other C2 hemilesioned rats with more extensive VM matter sparing (ipsilateral-to-contralateral white matter ratio = 0.55 ± 0.05), respiratory deficits were indicated at 1 mo post-injury by reduced ventilation during hypercapnic challenge (p < 0.05 vs. uninjured). Anterograde (ventral respiratory column-to-spinal cord) neuroanatomical tracing studies showed that descending respiratory projections from the brainstem are present in VM tissue. We conclude that even relatively minimal sparing of VM tissue after C2 hemilesion can alter respiratory outcomes. In addition, respiratory deficits can emerge in the adult rat after high cervical SCI even when relatively extensive VM sparing occurs.     

Phrenic nerve stimulation in patients with spinal cord injury

Phrenic nerve pacing (PNP) is a clinically useful technique to restore inspiratory muscle function in patients with respiratory failure secondary to cervical spinal cord injury. In this review, patient evaluation, equipment, methods of implementation, clinical outcomes, and the complications and side effects of PNP are discussed. Despite considerable technical development, and clinical success, however, current PNP systems have significant limitations. Even in patients with intact phrenic nerve function, PNP is successful in achieving full-time support in ～50% of patients. Inadequate inspired volume generation may arise secondary to incomplete diaphragm activation, reversed recruitment order of motor units, fiber type conversion resulting in reduced force generating capacity and lack of coincident intercostal muscle activation. A novel method of pacing is under development which involves stimulating spinal cord tracts which synapse with the inspiratory motoneuron pools. This technique results in combined activation of the intercostal muscles and diaphragm in concert and holds promise to provide a more physiologic and effective method of PNP.     

脊髓损伤后骨骼肌变化及预后的研究进展

脊髓损伤是脊柱骨折严重的并发症。由于椎体的移位或碎片骨突出于椎管内,使脊髓产生不同程度的损伤。在脊髓损伤之后,其效应器之一,骨骼肌将不可避免的发生一些相应的变化:凋亡、萎缩、运动单位的改变;肌肉兴奋性、收缩能力的改变;肌球蛋白重链的表达以及3-磷酸甘油脱氢酶活性的改变等,这些变化影响脊髓损伤的预后及患者的生活质量。目前针对脊髓损伤后骨骼肌变化的研究方法主要是从运动训练及电刺激这两方面。