Reactive balance responses to an unexpected slip perturbation in individuals with incomplete spinal cord injury

BackgroundFrequent falls while walking among individuals with incomplete spinal cord injury may suggest impairments in reactive balance control; however, reactive balance control during walking has not been studied in this population. The objective was to compare reactive balance control with respect to changes in margin of stability, onset of arm and heel responses, and onset and magnitude of muscle activity following an unexpected slip perturbation in individuals with incomplete spinal cord injury and able-bodied individuals.MethodsKinematic and electromyography data were obtained during normal walking and one unexpected slip. Changes in margin of stability following a compensatory or aborted step, onset of arms and trail heel responses, and onset and magnitude of activation of the tibialis anterior, soleus and gluteus medius were calculated. Multivariate analyses compared responses between incomplete spinal cord injury and able-bodied groups.FindingsData from 16 participants with incomplete spinal cord injury (all American Spinal Injury Association Impairment Scale Grade D, 8 with tetraplegia) and 13 age-and-sex matched able-bodied individuals were included. Individuals with incomplete spinal cord injury demonstrated limited ability to increase margin of stability in the lateral direction during a compensatory or aborted step, and a smaller magnitude of soleus activity compared to able-bodied individuals.InterpretationThere are limitations in reactive balance control of individuals with incomplete spinal cord injury, which may be a reason for the high frequency of falls in this population. Reactive balance assessment should be included as a component of routine balance assessment and fall avoidance strategies in this population.     

Balance and ambulation improvements in individuals with chronic incomplete spinal cord injury using locomotor training-based rehabilitation

Harkema SJ, Schmidt-Read M, Lorenz DJ, Edgerton VR, Behrman AL. Balance and ambulation improvements in individuals with chronic incomplete spinal cord injury using locomotor training–based rehabilitation.ObjectiveTo evaluate the effects of intensive locomotor training on balance and ambulatory function at enrollment and discharge during outpatient rehabilitation after incomplete SCI.DesignProspective observational cohort.SettingSeven outpatient rehabilitation centers from the Christopher and Dana Reeve Foundation NeuroRecovery Network (NRN).ParticipantsPatients (N=196) with American Spinal Injury Association Impairment Scale (AIS) grade C or D SCI who received at least 20 locomotor training treatment sessions in the NRN.InterventionsIntensive locomotor training, including step training using body-weight support and manual facilitation on a treadmill followed by overground assessment and community integration.Main Outcome MeasuresBerg Balance Scale; Six-Minute Walk Test; 10-Meter Walk Test.ResultsOutcome measures at enrollment showed high variability between patients with AIS grades C and D. Significant improvement from enrollment to final evaluation was observed in balance and walking measures for patients with AIS grades C and D. The magnitude of improvement significantly differed between AIS groups for all measures. Time since SCI was not associated significantly with outcome measures at enrollment, but was related inversely to levels of improvement.ConclusionsSignificant variability in baseline values of functional outcome measures is evident after SCI in individuals with AIS grades C and D and significant functional recovery can continue to occur even years after injury when provided with locomotor training. These results indicate that rehabilitation, which provides intensive activity-based therapy, can result in functional improvements in individuals with chronic incomplete SCI.     

Quantifying muscle coactivation in individuals with incomplete spinal cord injury using wavelets

BackgroundIndividuals with incomplete spinal cord injury often have decreased gait function and coactivation of antagonistic muscle pairs. Common ways of quantifying coactivation using electromyographic signals do not consider frequency information in the signal. As electromyographic signals from different motor unit types have different frequency components and muscle fiber type can change in individuals with spinal cord injury, it may be beneficial to consider frequency components. The aims were to demonstrate the utility of using a method which considers temporal and frequency components of the electromyographical signal to quantify coactivation in lower extremity muscles in individuals with incomplete spinal cord injury through 1) comparison with able-bodied individuals and 2) comparison before and after body weight supported treadmill training.MethodsFrequency decomposition techniques were applied to electromyographical signals to consider the temporal and frequency components of the electromyographical signals to quantify coactivation over a range of frequencies.ResultsOur main findings show that correlation coefficients between total EMG intensities of rectus femoris-biceps femoris and medial gastrocnemius-tibialis anterior were significantly different between able-bodied individuals and those with incomplete spinal cord injury (p = 0006, p = 0.01). The correlation spectra of medial gastrocnemius-tibialis anterior of the spinal cord injury group were substantially different than those the able-bodied group, while the EMG normalcy score was significantly different (p = 0.002). We also found that there was a change in coactivation of ankle muscles after body weight supported treadmill training.InterpretationOur findings indicate that there may be frequency specific differences in muscle coactivation between able-bodied individuals and those with incomplete spinal cord injury. Changes in coactivation were also observed before and after body weight supported treadmill training. These differences may reflect the changes in recruitment patterns of different motor unit types.     

Speed impacts frontal-plane maneuver stability of individuals with incomplete spinal cord injury

BackgroundFollowing incomplete spinal cord injury, people often move slowly in an effort to maintain stability during walking maneuvers. Here we examine how maneuver speed impacts frontal-plane stability in people with incomplete spinal cord injury. We hypothesized that the challenge to control frontal-plane stability would increase with maneuver speed; specifically, the minimum lateral margin of stability would be smaller and the required coefficient of friction to avoid a slip would be greater during fast vs. preferred speed maneuvers.MethodsWe measured kinematics and ground reaction forces as 12 individuals with incomplete spinal cord injury performed side-step, lateral maneuvers at preferred and fast speeds. We examined four sequential steps: the Setup and Pushoff steps initiated the maneuver, and the Landing and Recovery steps arrested the maneuver.FindingsOur hypotheses were partially supported. Maneuver time was shorter during fast vs. preferred speed maneuvers (p = 0.003). Minimum lateral margin of stability was smaller during the Setup step of fast vs. preferred speed maneuvers (p = 0.026). We found no differences in minimum lateral margin of stability between speeds for the Landing and Recovery steps (p > 0.05). The required coefficient of friction was not different between fast and preferred speed maneuvers (p = 0.087).InterpretationThe greatest effect of increasing maneuver speed occurred during the Setup step; as speed increased, participants reduced their minimum lateral margin of stability ipsilateral to the maneuver direction. This action allowed maneuvers to be performed more quickly without requiring a greater lateral impulse during the Pushoff step. However, this strategy reduced passive stability.     

Dynamic longitudinal evaluation of the utility of the berg balance scale in individuals with motor incomplete spinal cord injury

Datta S, Lorenz DJ, Harkema SJ. Dynamic longitudinal evaluation of the utility of the Berg Balance Scale in individuals with motor incomplete spinal cord injury.ObjectivesTo examine the utility of the Berg Balance Scale among patients with motor incomplete spinal cord injuries (SCIs), to determine how the utility of the Berg Balance Scale changes over time with activity-based therapy, and to identify differences in scale utility across patient groups defined by status of recovery.DesignProspective observational cohort.SettingThe NeuroRecovery Network (NRN), a network of clinical centers for patients with motor incomplete SCI.ParticipantsPatients with motor incomplete SCI (n=124) with American Spinal Injury Association Impairment Scale grade C or D, who were enrolled in the NRN between February 2008 and June 2009.InterventionStandardized locomotor training.Main Outcome MeasureThe Berg Balance Scale items were examined with longitudinal principal components analyses. Patients were categorized by phase using the Neuromuscular Recovery Scale.ResultsIn the full sample, the first principal component explained a large percentage of overall scale variance (77%), items were loaded homogeneously on the first principal component, and item scores were well correlated with first principal component scores. In subgroups of low and high functioning of patients, first principal component variance accounting was reduced (49%) and only a few of the simplest and most difficult items substantially loaded onto the first principal component. Item loading coefficients evolved over time as patients recovered, with simpler items becoming less important to the full scale and difficult items more important.ConclusionsThe utility of the Berg Balance Scale in patients with motor incomplete SCI in early and advanced phases of recovery is limited. Specific item utility changes as patients recover. Thus, a more comprehensive and dynamic instrument is necessary to adequately measure balance across the spectrum of patients with motor incomplete SCI.     

Locomotor training progression and outcomes after incomplete spinal cord injury

BACKGROUND AND PURPOSE: The use of locomotor training with a body-weight-support system and treadmill (BWST) and manual assistance has increased in rehabilitation. The purpose of this case report is to describe the process for retraining walking in a person with an incomplete spinal cord injury (SCI) using the BWST and transferring skills from the BWST to overground assessment and community ambulation. CASE DESCRIPTION: Following discharge from rehabilitation, a man with an incomplete SCI at C5-6 and an American Spinal Injury Association (ASIA) Impairment Scale classification of D participated in 45 sessions of locomotor training. OUTCOMES: Walking speed and independence improved from 0.19 m/s as a home ambulator using a rolling walker and a right ankle-foot orthosis to 1.01 m/s as a full-time ambulator using a cane only for community mobility. Walking activity (mean+/-SD) per 24 hours increased from 1,054+/-543 steps to 3,924+/-1,629 steps. DISCUSSION: In a person with an incomplete SCI, walking ability improved after locomotor training that used a decision-making algorithm and progression across training environments.     

Robotic-assisted, body-weight-supported treadmill training in individuals following motor incomplete spinal cord injury

BACKGROUND AND PURPOSE: Performance of therapist-assisted, body-weight-supported treadmill training (BWSTT) to enhance walking ability of people with neurological injury is an area of intense research. Its application in the clinical setting, however, is limited by the personnel and labor requirements placed on physical therapists. Recent development of motorized ("robotic") rehabilitative devices that provide assistance during stepping may improve delivery of BWSTT. CASE DESCRIPTION: This case report describes the use of a robotic device to enhance motor recovery and ambulation in 3 people following motor incomplete spinal cord injury. INTERVENTIONS: Changes in motor impairment, functional limitations, and locomotor disability were monitored weekly during robotic-assisted BWSTT and following transition to therapist-assisted BWSTT with the assistance of one therapist. OUTCOMES: Following this training, 2 patients recovered independent over-ground walking and another improved his gait speed and endurance. DISCUSSION: The use of robotic devices may assist physical therapists by providing task-specific practice of stepping in people following neurological injury.     

An intensive intervention for improving gait, balance, and mobility in individuals with chronic incomplete spinal cord injury: a pilot study of activity tolerance and benefits

Fritz SL, Merlo-Rains AM, Rivers ED, Peters DM, Goodman A, Watson ET, Carmichael BM, McClenaghan BA. An intensive intervention for improving gait, balance, and mobility in individuals with chronic incomplete spinal cord injury: a pilot study of activity tolerance and benefits.

Objective

To determine the tolerance to and benefits of an intensive mobility training (IMT) approach for individuals with incomplete spinal cord injury (ISCI).

Design

Prospective pretest-posttest study with 6-month follow-up.

Setting

University research laboratory.

Participants

A volunteer sample of individuals with ISCI (N=15; >6mo postinjury and able to walk at least 3.05m with or without assistance). Follow-up data were collected for 10 of the participants.

Interventions

Participants received IMT for 3h/d for 10 weekdays, participating in activities that encouraged repetitive, task-specific training of their lower extremities in a massed practice schedule.

Main Outcome Measures

Amount of time spent in therapeutic activities and rest was used to assess participants' tolerance to the intervention. Treatment outcomes were assessed pretest, posttest, and 6 months after the intervention and included the Berg Balance Scale (BBS), Dynamic Gait Index (DGI), 6-minute walk test, gait speed, and Spinal Cord Injury Functional Ambulation Inventory.

Results

Individuals in the higher functioning ISCI group (BBS score ≥45 and gait speed ≥0.6m/s) spent more time in the intensive therapy on average than individuals in the lower functioning ISCI group. Effect sizes were comparable for changes in balance and mobility assessments between the lower and higher functioning groups, with the largest effect sizes observed for the DGI.

Conclusions

This dosage of IMT may be a more appropriate treatment approach for higher functioning ISCI individuals, as they were better able to tolerate the length of the session and demonstrated higher effect sizes postintervention.     

Longitudinal patterns of functional recovery in patients with incomplete spinal cord injury receiving activity-based rehabilitation

Lorenz DJ, Datta S, Harkema SJ. Longitudinal patterns of functional recovery in patients with incomplete spinal cord injury receiving activity-based rehabilitation.ObjectiveTo model the progression of 3 functional outcome measures from patients with incomplete spinal cord injury (SCI) receiving standardized locomotor training.DesignObservational cohort.SettingThe NeuroRecovery Network (NRN), a specialized network of treatment centers providing standardized, activity-based therapy for SCI patients.ParticipantsPatients (N=337) with incomplete SCI (grade C or D on the International Standards for Neurological Classification of Spinal Cord Injury scale) who were enrolled in the NRN between February 2008 and March 2011.InterventionAll enrolled patients received standardized locomotor training sessions, as established by NRN protocol, and were evaluated monthly for progress.Main Outcome MeasuresBerg Balance Scale, 6-minute walk test, and 10-meter walk test. Progression over time was analyzed via the fitting of linear mixed effects models.ResultsThere was significant improvement on each outcome measure and significant attenuation of improvement over time. Patients varied significantly across groups defined by recovery status and American Spinal Injury Association Impairment Scale (AIS) grade at enrollment with respect to baseline performance and rates of change over time. Time since SCI was a significant determinant of the rate of recovery for all measures.ConclusionsLocomotor training, as implemented in the NRN, results in significant improvement in functional outcome measures as treatment sessions accumulate. Variability in patterns of recovery over time suggest that time since SCI and patient functional status at enrollment, as measured by the Neuromuscular Recovery Scale, are important predictors of performance and recovery as measured by the targeted outcome measures.     

Clinical presentations, medical complications, and functional outcomes of individuals with gunshot wound-induced spinal cord injury

Gunshot wounds are currently the second leading cause of spinal cord injury in the United States, and coexisting injuries or complications accompanying penetrating wounds often increase patient morbidity. A review of 217 traumatic spinal cord injury rehabilitation admissions to a tertiary care hospital during a 5-yr period revealed 49 individuals (23%) with gunshot wound-induced spinal cord injury. A single bullet entry site was seen in 54%, whereas 17% had greater than 3 sites of entry. Common (>25%) sites of bullet entry included the back, abdomen, neck, and chest. Common gunshot wound-related medical complications included pain (54%), infections (40%), pneumothorax (24%), nonspinal fractures (22%), colonic perforation (17%), cerebrospinal fluid leak (10%), and retroperitoneal hematoma (10%). When compared with nonviolence-related traumatic spinal cord injury (motor vehicle accidents and falls), patients with gunshot wound-induced spinal cord injury were significantly more frequently (P < 0.01) younger, non-Caucasian, unmarried, and unemployed. Injury characteristics revealed significantly (P < 0.01) more paraplegia and complete spinal cord injury within the gunshot wound-induced spinal cord injury group. Gunshot wound-induced spinal cord injury and nonviolent traumatic spinal cord injury groups had similar lengths of stay, Functional Independence Measure scores, and discharge to home rates. This article adds to the growing body of literature examining clinical, medical, and functional outcome characteristics of individuals with spinal cord injury secondary to violence-related cause.     

Spinal cord injury-functional index: item banks to measure physical functioning in individuals with spinal cord injury

Tulsky DS, Jette AM, Kisala PA, Kalpakjian C, Dijkers MP, Whiteneck G, Ni P, Kirshblum S, Charlifue S, Heinemann AW, Forchheimer M, Slavin MD, Houlihan B, Tate DG, Dyson-Hudson T, Fyffe D, Williams S, Zanca J. Spinal Cord Injury-Functional Index: item banks to measure physical functioning in individuals with spinal cord injury.ObjectivesTo develop a comprehensive set of patient-reported items to assess multiple aspects of physical functioning relevant to the lives of people with spinal cord injury (SCI), and to evaluate the underlying structure of physical functioning.DesignCross-sectional.SettingInpatient and community.ParticipantsItem pools of physical functioning were developed, refined, and field tested in a large sample of individuals (N=855) with traumatic SCI stratified by diagnosis, severity, and time since injury.InterventionsNone.Main Outcome MeasureSpinal Cord Injury-Functional Index (SCI-FI) measurement system.ResultsConfirmatory factor analysis (CFA) indicated that a 5-factor model, including basic mobility, ambulation, wheelchair mobility, self-care, and fine motor function, had the best model fit and was most closely aligned conceptually with feedback received from individuals with SCI and SCI clinicians. When just the items making up basic mobility were tested in CFA, the fit statistics indicated strong support for a unidimensional model. Similar results were demonstrated for each of the other 4 factors, indicating unidimensional models.ConclusionsThough unidimensional or 2-factor (mobility and upper extremity) models of physical functioning make up outcomes measures in the general population, the underlying structure of physical function in SCI is more complex. A 5-factor solution allows for comprehensive assessment of key domain areas of physical functioning. These results informed the structure and development of the SCI-FI measurement system of physical functioning.     

Employment satisfaction of individuals with spinal cord injury

OBJECTIVES: Community reentry after a spinal cord injury is a long-term integrative process, because individuals must adjust to an extraordinary new set of circumstances. In this study, quality-of-life and work satisfaction variables associated with employed or unemployed individuals with spinal cord injury were examined. METHODS: Quality-of-life and work satisfaction variables associated with 109 employed or unemployed individuals with spinal cord injury were examined by using an employment satisfaction survey. RESULTS: Most of those employed indicated that they would either change jobs or some employment variable such as duties, supervisor, or hours worked. Participants who were not working attributed unemployment to an array of factors including ongoing health problems, lack of transportation, and impact of and/or lost disability benefits. Both groups offered feedback related to information provided to them by medical professionals about return-to-work resources. CONCLUSIONS: The following three themes emerged from this analysis: (1) more comprehensive provider training about spinal cord injury is needed; (2) increased communication between consumer and family would be beneficial; and (3) an increase in the flexibility and availability of services would help to ensure access to essential care.     

Combined use of body weight support, functional electric stimulation, and treadmill training to improve walking ability in individuals with chronic incomplete spinal cord injury

OBJECTIVE: To assess the effect of an intervention combining body weight support (BWS), functional electric stimulation (FES), and treadmill training on overground walking speed (OGWS), treadmill walking speed, speed and distance, and lower extremity motor scores (LEMS). DESIGN: Before and after comparison. SETTING: Miami Project to Cure Paralysis. PARTICIPANTS: Nineteen subjects with American Spinal Injury Association class C injury who were at least 1 year postinjury and had asymmetrical lower extremity function. INTERVENTION: Subjects trained 1.5 hours per day, 3 days per week, for 3 months. The training consisted of body weight-supported treadmill walking assisted by electric stimulation. Stimulation was applied to common peroneal nerve of the weaker lower extremity (LE) and timed to assist with the swing phase of the step cycle. MAIN OUTCOME MEASURES: OGWS in the absence of both BWS and FES; LEMS, and treadmill training parameters of speed and distance. RESULTS: Over the course of training, there was a significant increase in OGWS (from.12 +/- 0.8m/s to .21 +/- .15m/s, p = .0008), treadmill walking speed (from .23 +/- .12m/s to.49 +/- .20m/s, p = .00003), and treadmill walking distance (from 93 +/- 84m to 243 +/- 139m, p = .000001). The median LEMS increased significantly for both the stimulated and nonstimulated leg (from 8 to 11 in the FES-assisted leg, from 15 to 18 in the nonassisted leg, p < .005 for each). CONCLUSIONS: All subjects showed improvement in OGWS and overall LE strength. Further research is required to delineate the essential elements of these particular training strategies.     

步行训练对不完全性脊髓损伤大鼠损伤部位周围组织可塑性的影响

目的探讨步行训练对不完全性脊髓损伤大鼠损伤部位周围组织可塑性的影响。 方法将雌性SD大鼠24只分为步行训练组和对照组,每组12只,制作第10胸椎段脊髓损伤模型。步行训练组在制作脊髓损伤模型后1周开始进行步行训练,共训练9周;对照组不接受干预。制作模型后每周利用BBB评分评定后肢运动功能,8周后取材进行免疫荧光染色、Western blotting和轴突示踪分析。 结果后肢运动功能：步行训练组在伤后4周（步行训练3周）时,BBB评分较对照组出现明显改善（P<0.05）,一直持续到实验结束（伤后第10周,P<0.01）。损伤部位神经丝(NF)免疫荧光染色分析：对照组胶质瘢痕中可见许多排列比较规则、与脊髓纵轴方向一致的NF阳性纤维穿行,步行训练组除了可见少量NF阳性纤维在胶质瘢痕中穿越,还可见较多的NF阳性纤维围绕空洞边缘延伸,其NF阳性纤维数量明显高于对照组（P<0.05）。损伤部位生长相关蛋白-43（GAP-43）表达：2组损伤部位周围均可见呈红色的排列凌乱的GAP-43表达,步行训练组GAP-43+组织免疫荧光灰度值较对照组高 (P<0.05)。皮质脊髓束再生:2组损伤部位尾侧均未见生物素化葡聚糖胺（BDA）标记的纤维。 结论步行训练能明显增强脊髓损伤大鼠后肢损伤部位组织的可塑性,促进大鼠后肢运动功能恢复,但未能促进皮质脊髓束的再生。     

The effects of backward walking training on balance and mobility in an individual with chronic incomplete spinal cord injury: A case report

Background/Purpose: Individuals with incomplete spinal cord injuries (ISCIs) commonly face persistent gait impairments. Backward walking training may be a useful rehabilitation approach, providing novel gait and balance challenges. However, little is known about the effects of this approach for individuals with ISCIs. The purpose of this case report was to describe the effects of backward walking training on strength, balance, and upright mobility in an individual with chronic ISCI. Methods: A 28-year-old female, 11-years post ISCI (C4, AIS D) completed 18-sessions of backward walking training on a treadmill with partial body-weight support and overground. Training emphasized stepping practice, speed, and kinematics. Outcome measures included: Lower Extremity Motor Score, Berg Balance Scale (BBS), Sensory Organization Test (SOT), 10-Meter Walk Test (10MWT), 3-meter backward walking test, Timed Up and Go (TUG), and Activities-Specific Balance Confidence (ABC) Scale. Results: Strength did not change. Improved balance was evident based on BBS (20 to 37/56) and SOT scores (27 to 40/100). Upright mobility improved based on TUG times (57 to 32.7 s), increased 10MWT speed (0.23 to 0.31 m/s), and backward gait speed (0.07 to 0.12 m/s). Additionally, self-reported balance confidence (ABC Scale) increased from 36.9% to 49.6%. Conclusions: The results suggest that backward walking may be a beneficial rehabilitation approach; examination of the clinical efficacy is warranted.     

光化学法诱导猫不完全脊髓损伤动物模型的建立

目的观察光化学法诱导猫脊髓损伤后的神经行为学、运动诱发电位及形态学改变,为研究脊髓损伤后神经再生与功能重建建立动物模型。 方法将15只猫根据冷光源照射时间不同随机分为40 min组、60 min组和80 min组。手术暴露脊髓后,用35 mg/kg体重的玫瑰红静脉注射,联合应用强度为3000 klx的冷光源照射T13脊髓节段。术后21 d内连续观察动物神经行为学改变;于术后第21天检测动物的运动诱发电位,并与术前结果比较;取材观察动物脊髓组织形态学改变。 结果3组动物在手术后21 d内的神经行为学评分结果显示,损伤后动物下肢功能神经行为学评分降低,损伤程度与光照时间成正比。60 min组和80 min组动物损伤后运动诱发电位波形消失。3组动物的脊髓都有明显的缺血性坏死改变。 结论光化学法可诱导猫脊髓内产生微血栓,从而使组织发生缺血性坏死。冷光源照射60 min、80 min的动物双下肢运动功能明显受损,与其病理学改变和电生理学改变相符,用这种方法制作不完全脊髓损伤模型稳定可靠。     

不完全性脊髓损伤患者与健康人步态变异性、对称性和协调性的对照研究

目的:通过观察不完全性脊髓损伤患者的步态变异性、对称性和协调性,更加全面了解脊髓损伤患者的步态特点。方法:选取22例不完全性脊髓损伤患者(观察组)及健康人(对照组),健康人按正常歩速及匹配患者速度行走分为(对照组A)及(对照组B),采用三维运动采集系统及足底压力采集系统进行步态测试。用步态变异值、对称值和相位协调指数表示步态变异性、对称性和协调性,比较3组受试者步态变异性、对称性和协调性的差异及与步行功能相关性。结果:观察组的步长变异值、站立相变异值及迈步相变异值均高于对照组A,观察组的步长对称值、站立相对称值、迈步相对称值和相位协调指数均低于对照组,且差异有统计学意义(P<0.05)。观察组的步态变异值、对称值和相位协调指数与脊髓损伤步行能力负相关。多元线性回归分析显示站立相变异值、站立相对称值和PCI对WISCI-II步行指数均有显著负影响,PCI对FIM步行指数有显著负相影响。结论:不完全性脊髓损伤患者的步态变异性、对称性和协调性均低于健康人,在为不完全性脊髓损伤患者制定康复训练方案时,应考虑步态变异性、对称性和协调性等指标对步行功能的影响。