Exercise-mediated locomotor recovery and lower-limb neuroplasticity after stroke

Assumptions that motor recovery plateaus within months after stroke are being challenged by advances in novel motor-learning-based rehabilitation therapies. The use of lower-limb treadmill (TM) exercise has been effective in improving hemiparetic gait function. In this review, we provide a rationale for treadmill exercise as stimulus for locomotor relearning after stroke. Recent studies using neuroimaging and neurophysiological measures demonstrate central nervous system (CNS) influences on lower-limb motor control and gait. As with studies of upper limbs, evidence shows that rapid transient CNS plasticity can be elicited in the lower limb. Such effects observed after short-term paretic leg exercises suggest potential mechanisms for motor learning with TM exercise. Initial intervention studies provide evidence that long-term TM exercise can mediate CNS plasticity, which is associated with improved gait function. Critical needs are to determine the optimal timing and intensities of TM therapy to maximize plasticity and learning effects.     

Effect of a vitamin D analog on leg bone mineral density in patients with chronic spinal cord injury

A randomized, placebo-controlled trial was performed to determine the effect of a vitamin D analog (1-alpha-hydroxyvitamin D(2) [1-alpha D(2)]) on the bone mineral density (BMD) in patients with chronic spinal cord injury (SCI). Forty subjects with chronic complete motor SCI were enrolled. The mean plus or minus standard deviation age and duration of injury were 42 plus or minus 12 yr and 11 plus or minus 10 yr, respectively. Either 4 micrograms 1-alpha D(2) (n = 19) or placebo (n = 21) was administered daily for 24 mo. Metabolic markers of bone resorption and formation were obtained. Regional lower-limb dual-energy x-ray absorptiometry was performed at baseline and at 6, 12, 18, and 24 mo. Leg BMD and percent change from baseline significantly increased at 6 (percent change only), 12, 18, and 24 mo in the treatment group, but not in the placebo group. Urinary N-telopeptide, a marker of bone resorption, was significantly reduced during treatment with 1-alpha D(2), but markers of bone formation were not changed.     

水中平板步行训练对脊髓损伤患者康复疗效的初步观察

目的观察水中平板步行训练对脊髓损伤患者的康复疗效。方法对11例外伤性不完全性脊髓损伤患者进行水中平板步行训练等康复治疗，记录水中平板步行训练前后的ASIA运动评分、ASIA感觉评分。以及训练时的行走距离、最大步速和训练前后的日常生活活动能力（ADL）评分变化。结果经水中平板步行训练后，患者的ASIA感觉评分提高（P〈0．05），ASIA运动评分、行走距离、最大步速及ADL评分明显提高（P〈0．01）。结论在常规康复治疗基础上进行水中平板步行训练可改善不完全性脊髓损伤患者的运动、感觉功能及生活自理能力。     

Improved intralimb coordination in people with incomplete spinal cord injury following training with body weight support and electrical stimulation

BACKGROUND AND PURPOSE: Limb coordination is an element of motor control that is frequently disrupted following spinal cord injury (SCI). The authors assessed intralimb coordination in subjects with SCI following a 12-week program combining body weight support, electrical stimulation, and treadmill training. SUBJECTS: Fourteen subjects with long-standing (mean time post-SCI=70 months, range=12-171 months), incomplete SCI participated. Three subjects without SCI provided data for comparison. METHODS: A vector-based technique was used to assign values to the frame-by-frame changes in hip/knee angle, and vector analysis techniques were used to assess how closely the hip/knee angles of each step cycle resembled those of every other step cycle. Overground and treadmill walking speeds also were measured. RESULTS: Following training, 9 of the 14 subjects with SCI demonstrated greater intercycle agreement. Mean overground and treadmill walking speeds improved (84% and 158%, respectively). DISCUSSION AND CONCLUSION: The intervention used in this study is based on our current understanding of the role of afferent input in the production of walking. Although the study sample was small and there was no control group, results suggest that training may improve intralimb coordination in people with SCI.     

水中活动平板训练对脊髓损伤大鼠体感、运动诱发电位及运动功能的影响

目的:探讨水中平板训练对脊髓损伤(SCI)大鼠体感诱发电位(SEP)、运动诱发电位(MEP)及运动功能的影响。方法:将成年雄性SD大鼠25只,随机分为假模组、模型对照组、水疗训练组、减重平板训练组和水中平板训练组。采用改良Allen’s打击法制作T10—11SCI模型,采用BBB评分、爬网格实验、SEP及MEP评定肢体功能及训练效果。结果:BBB评分及爬网格实验显示,水中平板训练组的大鼠后肢运动功能较其他组明显改善(P<0.05)。SEP、MEP的潜伏期,三组训练组较模型对照组均有显著缩短(P<0.05);但三组训练组之间MEP潜伏期差异无显著性意义(P>0.05)。水中平板训练组较减重平板训练组SEP、MEP波幅明显增大,差异均有显著性意义(P<0.05)。结论:三组训练对脊髓损伤大鼠SEP、MEP及运动功能均有不同程度的促进恢复作用,其中水中平板训练最为显著。     

Gait training in human spinal cord injury using electromechanical systems: effect of device type and patient characteristics

Benito-Penalva J, Edwards DJ, Opisso E, Cortes M, Lopez-Blazquez R, Murillo N, Costa U, Tormos JM, Vidal-Samsó J, Valls-Solé J, European Multicenter Study about Human Spinal Cord Injury Study Group, Medina J. Gait training in human spinal cord injury using electromechanical systems: effect of device type and patient characteristics.ObjectiveTo report the clinical improvements in spinal cord injury (SCI) patients associated with intensive gait training using electromechanical systems according to patient characteristics.DesignProspective longitudinal study.SettingInpatient SCI rehabilitation center.ParticipantsAdults with SCI (n=130).InterventionPatients received locomotor training with 2 different electromechanical devices, 5 days per week for 8 weeks.Main Outcome MeasuresLower-extremity motor score, Walking Index for Spinal Cord Injury, and 10-meter walking test data were collected at the baseline, midpoint, and end of the program. Patients were stratified according to the American Spinal Injury Association (ASIA) category, time since injury, and injury etiology. A subgroup of traumatic ASIA grade C and D patients were compared with data obtained from the European Multicenter Study about Human Spinal Cord Injury (EM-SCI).ResultsOne hundred and five patients completed the program. Significant gains in lower-limb motor function and gait were observed for both types of electromechanical device systems, to a similar degree. The greatest rate of improvement was shown in the motor incomplete SCI patients, and for patients <6 months postinjury. The positive response associated with training was not affected by injury etiology, age, sex, or lesion level. The trajectory of improvement was significantly enhanced relative to patients receiving the conventional standard of care without electromechanical systems (EM-SCI).ConclusionsThe use of electromechanical systems for intensive gait training in SCI is associated with a marked improvement in lower-limb motor function and gait across a diverse range of patients and is most evident in motor incomplete patients, and for patients who begin the regimen early in the recovery process.     

Effect of Locomotor Training on Motor Recovery and Walking Ability in Patients with Incomplete Spinal Cord Injury: A Case Series

[Purpose] The aim of this study was to describe the effect of locomotor training on a treadmill for three individuals who have an incomplete spinal cord injury (SCI). [Subjects and Methods] Three indivduals (2 males, 1 female) with incomplete paraplegia participated in this prospective case series. All subjects participated in locomotor training for a maximum of 20 minutes on a motorized treadmill without elevation at a comfortable walking speed three days a week for four weeks as an adjunct to a conventional physiotherapy program. The lower extremity strength and walking capabilities were used as the outcome measures of this study. Lower extremity strength was measured by lower extremity motor score (LEMS). Walking capability was assessed using the Walking Index for Spinal Cord Injury (WISCI II). [Results] An increase in lower extremity motor score and walking capabilities at the end of training program was found. [Conclusion] Gait training on a treadmill can enhance motor recovery and walking capabilities in subjects with incomplete SCI. Further research is needed to generalize these findings and to identify which patients might benefit from locomotor training.Key words: Locomotor training, Spinal cord injury, Paraplegia     

Neuroanatomical substrates of functional recovery after experimental spinal cord injury: implications of basic science research for human spinal cord injury

Human spinal cord injury (SCI) is a devastating condition that results in persistent motor deficits. Considerable basic and clinical research is directed at attenuating these deficits. Many basic scientists use animal models of SCI to (1) characterize lesion development, (2) determine the role of spared axons in recovery, and (3) develop therapeutic interventions based on these findings. In this article, current research is reviewed that indicates: (1) most individuals with SCI will have some sparing of white matter at the lesion epicenter even when the lesion appears clinically complete, (2) even minimal tissue sparing has a profound impact on segmental systems and recovery of function, and (3) facilitatory intervention such as weight bearing and locomotor training after SCI may be more effective than compensatory strategies at inducing neuroplasticity and motor recovery. Body weight supported treadmill step training is discussed as an example of new facilitatory interventions based on basic science research using animal models.     

Fracture threshold in the femur and tibia of people with spinal cord injury as determined by peripheral quantitative computed tomography

OBJECTIVE: To determine bone traits of the femur and tibia with peripheral quantitative computed tomography (pQCT) that best distinguish between spinal cord injury (SCI) subjects with and without fractures. DESIGN: Cross-sectional study. SETTING: In- and outpatient paraplegic center in Switzerland. PARTICIPANTS: Ninety-nine motor complete SCI subjects (duration of paralysis, 2 mo-49 y), 21 of whom had sustained fractures of the femur or tibia. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Subjects with SCI were questioned about the occurrence, location, and approximate date of fractures to their lower extremities. Trabecular and cortical bone mineral density (BMD), as well as bone geometric properties of distal epiphyses and midshafts of the femur and tibia, were measured by pQCT. RESULTS: Trabecular BMD of the femur and tibia distal epiphyses was found to distinguish best subjects with fractures from those without. Fractures occurred in subjects with trabecular BMD of less than 114 mg/cm 3 and less than 72 mg/cm 3 for the femoral and tibial distal epiphysis, respectively (corresponding to 46% and 29% of mean values of an able-bodied reference group). Approximately 50% of the subjects with chronic SCI (defined as time postinjury >5 y for femur data and >7 y for tibia data) had trabecular BMD values above the fracture threshold in the femur and about one third above the fracture threshold in the tibia. CONCLUSIONS: By using pQCT, it may be possible to identify subjects with SCI who are at risk of sustaining fractures of the femur and tibia through minor trauma.     

Bone mineral density after spinal cord injury: a reliable method for knee measurement

OBJECTIVES: To test the interrater reliability of a standardized method to analyze knee bone mineral density (BMD) using dual-energy x-ray absorptiometry (DXA); to compare spine, hip, and knee BMD of people with spinal cord injury (SCI) with able-bodied controls; and to determine the relation between hip BMD and knee BMD in SCI and able-bodied subjects. DESIGN: Criterion standard and masked comparison. SETTING: Primary care university hospital. PARTICIPANTS: A convenience sample of 11 subjects with complete SCI was age and sex matched with 11 able-bodied control subjects. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Four raters analyzed regions of interest according to operational definitions recently developed to standardize the analysis of BMD of the knee. Subjects with chronic SCI and matched controls underwent conventional DXA scans of the spine and hips and "less conventional" scans of the distal femurs and proximal tibias. The relation between hip and knee BMD was analyzed. RESULTS: The knee measurements were highly reliable (femur intraclass correlation coefficient model 2,1 [ICC(2,1)]=.98; tibia ICC(2,1)=.89). Subjects with SCI had lower BMD values than controls at all hip and knee sites (P<.05). Lumbar spine BMD did not differ between groups. Hip BMD was moderately predictive of distal femur BMD (R2=.67), but less correlated with the proximal tibia (R2=.38). CONCLUSIONS: Knee BMD can be reliably analyzed using DXA with this protocol. Subjects with SCI have diminished knee and hip BMD. Low hip BMD is associated with low distal femur BMD.     

Bone mineral density after bicycle ergometry training

The effect of functional electrical stimulation (FES) cycle ergometry on bone mineral density (BMD) was investigated in six spinal cord injury (SCI) quadriplegic men. Each subject trained three days a week for six months on an FES cycle ergometer. Pretraining and posttraining BMD measurements of the proximal femur were performed using dual photon absorptiometry. Mean pretraining BMD (percent norm) for the femoral neck, Ward triangle, and trochanter were 66.65, 57.43, and 57.67, respectively. After six months of FES cycle ergometry, mean BMD measurements were 66.15, 57.07, and 55.13, respectively. There was no statistically significant difference between the pretraining and posttraining BMD measurements. All subjects were found to have osteoporotic proximal femurs when BMD was expressed as a percent of their age-matched controls. Bone mineral density measurements were subsequently performed on three additional men with SCI who had exercised for three years with the FES cycle ergometry modality. Their mean BMDs were not significantly different from the experimental group. This study demonstrated that six months of FES cycle ergometry did not produce an increase in BMD.     

Relationship between regional bone density measurements and the time since injury in adults with spinal cord injuries

OBJECTIVES: To determine the bone mineral density (BMD) of the legs, arms, and trunk region of a group of adults with spinal cord injury (SCI) and to determine the relationship between regional BMD values and the time since injury. DESIGN: BMD measurements were determined by total-body, dual-energy x-ray absorptiometry scans and percentage values (percentage-matched BMD), based on manufacturer-supplied normative data for age, sex, body weight, and ethnic group. The relationship between percentage-matched BMD values and time since injury was determined by linear regression analyses. SETTING: Research laboratories in a university setting. PARTICIPANTS: Twenty-nine subjects (21 men, 8 women; mean age, 38.5 y) who had sustained an SCI a mean of 10.6 years earlier (range, 0.6-35.3 y). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The relationship between percentage-matched BMD values and the time since injury. RESULTS: There was a significant inverse relationship between percentage-matched BMD leg (r2 = -.76), arm (r2 = -.45), and trunk (r2 = -.38) values and the log of time since injury. CONCLUSION: Despite the varying levels of SCI and other relevant BMD contributing factors, the regional percentage-matched BMD values were significantly inversely related to the log of time since injury.     

阿法骨化醇及二膦酸盐类药物对脊髓损伤患者骨密度的影响

目的探讨阿法骨化醇及二膦酸盐类药物对脊髓损伤患者骨密度的影响。方法分别比较 3 1例口服阿法骨化醇与42例未口服该药的脊髓损伤患者 ,以及 2 2例口服二膦酸盐类药物与 2 4例未口服该药的脊髓损伤患者第 4腰椎和股骨近端及其分区骨密度变化的差异。结果是否口服阿法骨化醇对脊髓损伤患者骨密度的保持无显著影响 ;但口服二膦酸盐类药物患者的股骨近端 (total)骨密度较未口服该药物患者下降少 ,两者的差异具有显著性意义 (P <0 .0 5 )。结论口服二膦酸盐类药物对股骨近端的骨密度变化有保护作用。     

The relationship between basal metabolic rate and femur bone mineral density in men with traumatic spinal cord injury

OBJECTIVES: To investigate the relationship between basal metabolic rate (BMR) and hip bone mineral density (BMD) in people with spinal cord injury (SCI) and to determine whether neurologic factors contribute to this relationship. DESIGN: Cross-sectional study. SETTING: Inpatient SCI unit in a rehabilitation hospital. PARTICIPANTS: Thirty men with chronic (time since injury, >1 y) traumatic SCI with an American Spinal Injury Association Impairment Scale grade A or B. Subjects' mean age was 32 years (range, 20-45 y). INTERVENTIONS: All participants were evaluated with neurologic examination to define the level and severity of injury. BMR was determined by indirect calorimetry, and BMD was determined by dual-energy x-ray absorptiometry (DXA). Patients were allocated to osteoporotic, osteopenic, and normal bone density groups according to World Health Organization criteria. DXA was used also to estimate lean- and fat-tissue mass (in kilograms) by standard methods. DXA measurements were performed on the same day as BMR analysis. MAIN OUTCOME MEASURES: DXA and indirect calorimetry. RESULTS: BMR correlated significantly with BMD of the total femur, femur neck, trochanter, and shaft. However, there was no correlation between BMR and femur Ward's triangle. These correlations were stronger in patients with tetraplegia. There was a moderate correlation between BMR and lean tissue mass (r = .66, P < .001), although femur BMD values did not correlate with lean tissue mass in our study group (P > .05). CONCLUSIONS: BMR is closely associated with BMD in men with SCI.     

早期干预对脊髓损伤大鼠骨密度的影响

目的：建立脊髓损伤(SCI)动物模型，探讨在SCI后早期应用阿仑膦酸钠(ALN)和，或脉冲电磁场(PEMFs)对SCI大鼠骨密度(BMD)的影响。方法：将62只3月龄健康雌性SD大鼠随机分为假手术(Sham)组、SCI组、SCI ALN组、SCI PEMFs组、SCI PEMFs ALN组，Sham组仅行椎板切除术，其余4组行T10椎体水平脊髓完全横向切断术。脊髓横断大鼠于术后1周开始应用ALN和，或PEMFs，ALN每次0．25mg/kg腹腔注射，每周3次，共7周；PEMFs 30min／d，共7周。所有动物于术后8周时取材，检测股骨BMD值。结果：3月龄健康雌性SD大鼠脊髓完全横断术后8周时股骨BMD显减低；PEMFs早期应用可使股骨整体、股骨中段及下端BMD显增高：ALN早期应用可使股骨整体、股骨中段及股骨上下端BMD显增高；在本实验条件下ALN作用比PEMFs更强、更全面：ALN及：PEMFs早期联合应用比二单独应用时在BMD方面表现出更好的改善趋势，但析因分析表明二早期联合应用的协同效应不显。结论：3月龄雌性健康SD大鼠脊髓完全横断术后8周时股骨已发生显的骨量丢失：ALN及PEMFs早期应用可抑制SCI后骨量丢失，其中ALN的作用比PEMFs更强。     

脊髓损伤对大鼠股骨骨密度与生物力学特性的影响

目的探讨脊髓损伤(spinal cord injury, SCI)对大鼠股骨生物力学和骨密度(bone mineral density, BMD)的影响. 方法将40只3月龄大鼠随机分为SCI组和对照组,SCI组于T10椎体处完全切断脊髓,对照组仅行椎板切除术.于术后3,6周分2批处死动物进行股骨骨密度和生物力学测定. 结果术后3周时SCI组大鼠股骨远端BMD较对照组显著下降(P<0.05);术后6周时SCI组股骨近端BMD与对照组比较,下降差异显著(P<0.05);股骨远端BMD较对照组下降差异非常显著(P<0.01);股骨干BMD与对照组相比有降低趋势,但无统计学意义.术后3周时股骨颈最大载荷、最大变形、结构刚度及能量吸收在2组间差异均无统计学意义.术后6周时最大变形、结构刚度和能量吸收均低于对照组(P均<0.05),最大载荷低于对照组,差异具有极显著性意义(P<0.01). 结论脊髓损伤后松质骨骨密度和生物力学性能的降低先于密质骨.脊髓损伤后6周时SCI组股骨松质骨的骨密度及生物力学参数均显著低于对照组,脊髓损伤后6周的大鼠可作为骨质疏松动物模型.     

Increases in bone mineral density after functional electrical stimulation cycling exercises in spinal cord injured patients

Purpose. To assess the change in bone mineral density (BMD) after spinal cord injury (SCI) and to evaluate whether BMD loss can be reversed with the intervention of functional electric stimulation cycling exercises (FESCE).

Methods. Fifteen males with SCI were included. Fifteen able-bodied males were also tested to compare BMD. In the SCI group, the FESCE was performed for six months, and then was discontinued in the subsequent six months. BMD was performed before the FESCE, immediately after six months of the FESCE, and at the end of the subsequent six months.

Results. Before the FESCE, the BMD of the SCI subjects in every site, except the lumbar spine, was lower than that of the able-bodied subjects. After six months of FESCE, BMD of the distal femur (DF) and proximal tibia (PT) increased significantly, and BMD of the calcaneus (heel) showed a trend of increase. However, the BMD in the DF, PT, and heel decreased significantly after the subsequent six months without FESCE. The BMD of the femoral neck (FN) decreased progressively throughout the programme.

Conclusions. Our study showed site-specific BMD changes after FESCE. The BMD loss in the DF and PT was partially reversed after six months of FESCE, but the effect faded once the exercise was discontinued.     

Increases in bone mineral density after functional electrical stimulation cycling exercises in spinal cord injured patients

Purpose.?To assess the change in bone mineral density (BMD) after spinal cord injury (SCI) and to evaluate whether BMD loss can be reversed with the intervention of functional electric stimulation cycling exercises (FESCE).

Methods.?Fifteen males with SCI were included. Fifteen able-bodied males were also tested to compare BMD. In the SCI group, the FESCE was performed for six months, and then was discontinued in the subsequent six months. BMD was performed before the FESCE, immediately after six months of the FESCE, and at the end of the subsequent six months.

Results.?Before the FESCE, the BMD of the SCI subjects in every site, except the lumbar spine, was lower than that of the able-bodied subjects. After six months of FESCE, BMD of the distal femur (DF) and proximal tibia (PT) increased significantly, and BMD of the calcaneus (heel) showed a trend of increase. However, the BMD in the DF, PT, and heel decreased significantly after the subsequent six months without FESCE. The BMD of the femoral neck (FN) decreased progressively throughout the programme.

Conclusions.?Our study showed site-specific BMD changes after FESCE. The BMD loss in the DF and PT was partially reversed after six months of FESCE, but the effect faded once the exercise was discontinued.     

Electromyographic and kinematic nondisabled gait differences at extremely slow overground and treadmill walking speeds

This study compared the kinematic and electromyographic (EMG) gait patterns of able-bodied adults at natural speed in contrast to extremely slow overground and treadmill walking speeds. Kinematic and EMG data were collected at three speeds (self-selected, 0.30 m/s, and 0.20 m/s). Eighteen subjects were evaluated for trunk and lower-limb motion and EMG of five lower-limb muscles. Significant reductions were found in segmental motion between natural speed and both slower gait speeds, accompanied by an expected reduction in cadence and stride. EMG patterns at slower speeds showed changes in timing and reduced magnitudes. Phasic timing of the proximal muscles showed the most changes with predominant coactivation, whereas the distal muscles remained consistent with the pattern at natural self-selected speed. Overground versus treadmill gait patterns revealed minimal differences. Consideration of the effects of slower walking speed may help clinicians create interventions to target primary gait deficits on overground or treadmill walking.     

Peripheral quantitative computed tomography: measurement sensitivity in persons with and without spinal cord injury

OBJECTIVES: To determine (1) the error attributable to external tibia-length measurements by using peripheral quantitative computed tomography (pQCT) and (2) the effect these errors have on scan location and tibia trabecular bone mineral density (BMD) after spinal cord injury (SCI). DESIGN: Blinded comparison and criterion standard in matched cohorts. SETTING: Primary care university hospital. PARTICIPANTS: Eight able-bodied subjects underwent tibia length measurement. A separate cohort of 7 men with SCI and 7 able-bodied age-matched male controls underwent pQCT analysis. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The projected worst-case tibia-length-measurement error translated into a pQCT slice placement error of +/-3 mm. We collected pQCT slices at the distal 4% tibia site, 3 mm proximal and 3 mm distal to that site, and then quantified BMD error attributable to slice placement. RESULTS: Absolute BMD error was greater for able-bodied than for SCI subjects (5.87 mg/cm(3) vs 4.5 mg/cm(3)). However, the percentage error in BMD was larger for SCI than able-bodied subjects (4.56% vs 2.23%). CONCLUSIONS: During cross-sectional studies of various populations, BMD differences up to 5% may be attributable to variation in limb-length-measurement error.