Walking after spinal cord injury: evaluation, treatment, and functional recovery

Amplify Gait to Improve Locomotor Engagement in Spinal Cord Injury (AGILE SCI) trial: study protocol for an assessor blinded randomized controlled trial

BACKGROUND

Among ambulatory people with incomplete spinal cord injury (iSCI), balance deficits are a primary factor limiting participation in walking activities. There is broad recognition that effective interventions are needed to enhance walking balance following iSCI. Interventions that amplify self-generated movements (e.g., error augmentation) can accelerate motor learning by intensifying sensorimotor feedback and facilitating exploration of motor control strategies. These features may be beneficial for retraining walking balance after iSCI. We have developed a cable-driven robot that creates a movement amplification environment during treadmill walking. The robot applies a continuous, laterally-directed, force to the pelvis that is proportional in magnitude to real-time lateral velocity. Our purpose is to investigate the effects of locomotor training in this movement amplification environment on walking balance. We hypothesize that for ambulatory people with iSCI, locomotor training in a movement amplification environment will be more effective for improving walking balance and participation in walking activities than locomotor training in a natural environment (no applied external forces).

METHODS

We are conducting a two-arm parallel-assignment intervention. We will enroll 36 ambulatory participants with chronic iSCI. Participants will be randomized into either a control or experimental group. Each group will receive 20 locomotor training sessions. Training will be performed in either a traditional treadmill environment (control) or in a movement amplification environment (experimental). We will assess changes using measures that span the International Classification of Functioning, Disability and Health (ICF) framework including 1) clinical outcome measures of gait, balance, and quality of life, 2) biomechanical assessments of walking balance, and 3) participation in walking activities quantified by number of steps taken per day.

DISCUSSION

Training walking balance in people with iSCI by amplifying the individual's own movement during walking is a radical departure from current practice and may result in new strategies for addressing balance impairments. Knowledge gained from this study will expand our understanding of how people with iSCI improve walking balance and how an intervention targeting walking balance affects participation in walking activities. Successful outcomes could motivate development of clinically feasible tools to replicate the movement amplification environment within clinical settings.

TRIAL REGISTRATION

NCT04340063.

Clinical Static Balance Assessment: A Narrative Review of Traditional and IMU-Based Posturography in Older Adults and Individuals with Incomplete Spinal Cord Injury

Maintaining a stable upright posture is essential for performing activities of daily living, and impaired standing balance may impact an individual's quality of life. Therefore, accurate and sensitive methods for assessing static balance are crucial for identifying balance impairments, understanding the underlying mechanisms of the balance deficiencies, and developing targeted interventions to improve standing balance and prevent falls. This review paper first explores the methods to quantify standing balance. Then, it reviews traditional posturography and recent advancements in using wearable inertial measurement units (IMUs) to assess static balance in two populations: older adults and those with incomplete spinal cord injury (iSCI). The inclusion of these two groups is supported by their large representation among individuals with balance impairments. Also, each group exhibits distinct aspects in balance assessment due to diverse underlying causes associated with aging and neurological impairment. Given the high vulnerability of both demographics to balance impairments and falls, the significance of targeted interventions to improve standing balance and mitigate fall risk becomes apparent. Overall, this review highlights the importance of static balance assessment and the potential of emerging methods and technologies to improve our understanding of postural control in different populations.

[Movement analysis in spinal cord injuries : Assistance in clinical decision making]

For motor incomplete spinal cord injured patients, improvement of walking function is an important aim in the rehabilitation program. In specialized treatment centers, the 6‑minute walking test, the 10-meter walking test or the timed-up-and-go test are used as an assessment tool to determine walking ability, but these tests are not able to assess the quality of gait. Marker-based movement analysis can be used as a reliable method to evaluate the gait pattern. This allows an objective assessment of gait quality over time or can be used to support therapy planning. The benefit of such an analysis is presented by means of two case studies.

Functional trajectories during innate spinal cord repair

Adult zebrafish are capable of anatomical and functional recovery following severe spinal cord injury. Axon growth, glial bridging and adult neurogenesis are hallmarks of cellular regeneration during spinal cord repair. However, the correlation between these cellular regenerative processes and functional recovery remains to be elucidated. Whereas the majority of established functional regeneration metrics measure swim capacity, we hypothesize that gait quality is more directly related to neurological health. Here, we performed a longitudinal swim tracking study for 60 individual zebrafish spanning 8 weeks of spinal cord regeneration. Multiple swim parameters as well as axonal and glial bridging were integrated. We established rostral compensation as a new gait quality metric that highly correlates with functional recovery. Tensor component analysis of longitudinal data supports a correspondence between functional recovery trajectories and neurological outcomes. Moreover, our studies predicted and validated that a subset of functional regeneration parameters measured 1 to 2 weeks post-injury is sufficient to predict the regenerative outcomes of individual animals at 8 weeks post-injury. Our findings established new functional regeneration parameters and generated a comprehensive correlative database between various functional and cellular regeneration outputs.

Data-driven characterization of walking after a spinal cord injury using inertial sensors

BACKGROUND

An incomplete spinal cord injury (SCI) refers to remaining sensorimotor function below the injury with the possibility for the patient to regain walking abilities. However, these patients often suffer from diverse gait deficits, which are not objectively assessed in the current clinical routine. Wearable inertial sensors are a promising tool to capture gait patterns objectively and started to gain ground for other neurological disorders such as stroke, multiple sclerosis, and Parkinson's disease. In this work, we present a data-driven approach to assess walking for SCI patients based on sensor-derived outcome measures. We aimed to (i) characterize their walking pattern in more depth by identifying groups with similar walking characteristics and (ii) use sensor-derived gait parameters as predictors for future walking capacity.

METHODS

The dataset analyzed consisted of 66 SCI patients and 20 healthy controls performing a standardized gait test, namely the 6-min walking test (6MWT), while wearing a sparse sensor setup of one sensor attached to each ankle. A data-driven approach has been followed using statistical methods and machine learning models to identify relevant and non-redundant gait parameters.

RESULTS

Clustering resulted in 4 groups of patients that were compared to each other and to the healthy controls. The clusters did differ in terms of their average walking speed but also in terms of more qualitative gait parameters such as variability or parameters indicating compensatory movements. Further, using longitudinal data from a subset of patients that performed the 6MWT several times during their rehabilitation, a prediction model has been trained to estimate whether the patient's walking speed will improve significantly in the future. Including sensor-derived gait parameters as inputs for the prediction model resulted in an accuracy of 80%, which is a considerable improvement of 10% compared to using only the days since injury, the present 6MWT distance, and the days until the next 6MWT as predictors.

CONCLUSIONS

In summary, the work presented proves that sensor-derived gait parameters provide additional information on walking characteristics and thus are beneficial to complement clinical walking assessments of SCI patients. This work is a step towards a more deficit-oriented therapy and paves the way for better rehabilitation outcome predictions.

Functional Trajectories during innate spinal cord repair

Adult zebrafish are capable of anatomical and functional recovery following severe spinal cord injury. Axon growth, glial bridging and adult neurogenesis are hallmarks of cellular regeneration during spinal cord repair. However, the correlation between these cellular regenerative processes and functional recovery remains to be elucidated. Whereas the majority of established functional regeneration metrics measure swim capacity, we hypothesize that gait quality is more directly related to neurological health. Here, we performed a longitudinal swim tracking study for sixty individual zebrafish spanning eight weeks of spinal cord regeneration. Multiple swim parameters as well as axonal and glial bridging were integrated. We established rostral compensation as a new gait quality metric that highly correlates with functional recovery. Tensor component analysis of longitudinal data supports a correspondence between functional recovery trajectories and neurological outcomes. Moreover, our studies predicted and validated that a subset of functional regeneration parameters measured 1 to 2 weeks post-injury is sufficient to predict the regenerative outcomes of individual animals at 8 weeks post-injury. Our findings established new functional regeneration parameters and generated a comprehensive correlative database between various functional and cellular regeneration outputs.

Step-to-step variability indicates disruption to balance control when linking the arms and legs during treadmill walking

We recently discovered that a rope-pulley system that mechanically coupling the arms, legs and treadmill during walking can assist with forward propulsion in healthy subjects, leading to significant reductions in metabolic cost. However, walking balance may have been compromised, which could hinder the potential use of this device for gait rehabilitation. We performed a secondary analysis by quantifying average step width, step length, and step time, and used their variability to reflect simple metrics of walking balance (n = 8). We predicted an increased variability in at least one of these metrics when using the device, which would indicate disruptions to walking balance. When walking with the device, subjects increased their average step width (p < 0.05), but variability in step width and step length remained similar (p’s > 0.05). However, the effect size for step length variability when compared to that of mechanical perturbation experiments suggest a minimal to moderate disruption in balance (Rosenthal ES = 0.385). The most notable decrement in walking balance was an increase in step time variability (p < 0.05; Cohen’s d = 1.286). Its effect size reveals a moderate disruption when compared to the effect sizes observed in those with balance deficits (effect sizes ranged between 0.486 to 1.509). Overall, we conclude that healthy subjects experienced minimal to moderate disruptions in walking balance when using with this device. These data indicate that in future clinical experiments, it will be important to not only consider the mechanical and metabolic effects of using such a device but also its potential to disrupt walking balance, which may be exacerbated in patients with poor balance control.

A Novel Balance Control Strategy Based on Enhanced Stability Pyramid Index and Dynamic Movement Primitives for a Lower Limb Human-Exoskeleton System

The lower limb exoskeleton is playing an increasing role in enabling individuals with spinal cord injury (SCI) to stand upright, walk, turn, and so on. Hence, it is essential to maintain the balance of the human-exoskeleton system during movements. However, the balance of the human-exoskeleton system is challenging to maintain. There are no effective balance control strategies because most of them can only be used in a specific movement like walking or standing. Hence, the primary aim of the current study is to propose a balance control strategy to improve the balance of the human-exoskeleton system in dynamic movements. This study proposes a new safety index named Enhanced Stability Pyramid Index (ESPI), and a new balance control strategy is based on the ESPI and the Dynamic Movement Primitives (DMPs). To incorporate dynamic information of the system, the ESPI employs eXtrapolated Center of Mass (XCoM) instead of the center of mass (CoM). Meanwhile, Time-to-Contact (TTC), the urgency of safety, is used as an automatic weight assignment factor of ESPI instead of the traditional manual one. Then, the balance control strategy utilizing DMPs to generate the gait trajectory according to the scalar and vector values of the ESPI is proposed. Finally, the walking simulation in Gazebo and the experiments of the human-exoskeleton system verify the effectiveness of the index and balance control strategy.

Towards a Mobile Gait Analysis for Patients with a Spinal Cord Injury: A Robust Algorithm Validated for Slow Walking Speeds

Spinal cord injury (SCI) patients suffer from diverse gait deficits depending on the severity of their injury. Gait assessments can objectively track the progress during rehabilitation and support clinical decision making, but a comprehensive gait analysis requires far more complex setups and time-consuming protocols that are not feasible in the daily clinical routine. As using inertial sensors for mobile gait analysis has started to gain ground, this work aimed to develop a sensor-based gait analysis for the specific population of SCI patients that measures the spatio-temporal parameters of typical gait laboratories for day-to-day clinical applications. The proposed algorithm uses shank-mounted inertial sensors and personalized thresholds to detect steps and gait events according to the individual gait profiles. The method was validated in nine SCI patients and 17 healthy controls walking on an instrumented treadmill while wearing reflective markers for motion capture used as a gold standard. The sensor-based algorithm (i) performed similarly well for the two cohorts and (ii) is robust enough to cover the diverse gait deficits of SCI patients, from slow (0.3 m/s) to preferred walking speeds.

Decreasing pressure injuries and acute care length of stay in patients with acute traumatic spinal cord injury

OBJECTIVES

Identifying factors associated with the occurrence of pressure injuries (PI) during acute care and with longer length of stay (LOS), focusing on modifiable factors that can be addressed and optimized by the acute rehabilitation team.

DESIGN

Prospective cohort study.

SETTING

A single Level-1 trauma center specialized in SCI care.

PARTICIPANTS

A cohort of 301 patients with acute TSCI was studied.

OUTCOME MEASURES

The primary outcome was the occurrence of PI during acute care stay. The secondary outcome was acute care LOS. Bivariate and multivariate logistic or linear regression analyses were performed to determine the association between non-modifiable factors and outcomes (PI of any stage and acute LOS), whereas bivariate and hierarchical multivariate logistic or linear regression analyses were used for modifiable factors.

RESULTS

When controlling for the level and severity of the TSCI, the occurrence of pneumonia (OR = 2.1, CI = 1.1-4.1) was significantly associated with the occurrence of PI. When controlling for the level and severity of the TSCI, the occurrence of medical complications (PI, urinary tract infection and pneumonia) and lesser daily therapy resulted in significantly longer acute care LOS (P < .001).

CONCLUSIONS

Prevention of PI occurrence and the optimization of the acute care LOS represent crucial challenges of the acute rehabilitation team, as they are significantly associated with higher functional outcomes. Patients who develop pneumonia may benefit from more aggressive prevention strategies to reduce PI occurrence. Systematic protocols for the prevention of complications as well as greater volume of therapy interventions should be considered to optimize the acute care LOS.

Effect of acceptance and commitment therapy on rehabilitation patients with spinal cord injury

This study aimed to explore the differences between the effectiveness of using a combination of rehabilitation and acceptance commitment therapy (ACT), and rehabilitation therapy alone for the treatment of spinal cord injury (SCI). The newly admitted patients with spinal cord injury whose post-traumatic stress disorder (PTSD) score was higher than 38 points were randomly categorized into the treatment group and control group, with 30 patients in each group. One group underwent ACT and rehabilitation treatment, while the other underwent rehabilitation treatment only. PTSD and functional independence measure (FIM) scores were evaluated. Changes in scores were compared between the two groups before, one month, two months, and three months after treatment. The total PTSD score in SCI patients who were treated with ACT was significantly different before and after treatment (P < 0.05). Total FIM scores were also significantly different before and after treatment (P < 0.05). The FIM score in the treatment group was significantly higher than that in the control group after 2 and 3 months of treatment (P < 0.05). The combination of rehabilitation therapy and ACT could immediately reduce stress levels and significantly improve impaired function, lifelong self-care ability, and the impact of rehabilitation therapy.

Reliability and Validity of the Functional Gait Assessment in Incomplete Spinal Cord Injury

Background

There are limited psychometrically sound measures to assess higher level balance in individuals with incomplete spinal cord injury (iSCI).

Objectives

To evaluate interrater and intrarater reliability and convergent validity of the Functional Gait Assessment (FGA) in individuals with iSCI.

Methods

Twelve participants (11 male, 1 female) 32 to 73 years old with chronic motor iSCI, American Spinal Injury Association Impairment Scale C (n = 2) or D (n = 10), were included. Participants completed five outcome measures during a single test session including lower extremity motor scores from the International Standards for the Neurological Classification of Spinal Cord Injury, FGA, 10-Meter Walk Test (10MWT), Walking Index for Spinal Cord Injury (WISCI-II), and the Spinal Cord Injury Functional Ambulation Profile (SCI-FAP).

Results

Inter- and intrarater reliability for the FGA were excellent. Interrater reliability was excellent with intraclass correlation coefficient (ICC) scores greater than 0.92 (p < .001). Interrater reliability against an expert was also excellent for all raters, with an ICC greater than or equal to 0.92 (p < .01). Intrarater reliability was excellent with an ICC score of greater than 0.91 (p < .002) for all raters. Validity of the FGA with 10MWT was -0.90 (p = .000), FGA with WISCI-II was 0.74 (p = .006), and FGA with SCI-FAP was -0.83 (p = .001).

Conclusion

The FGA is a reliable and valid outcome measure to use when assessing gait and balance in individuals with motor iSCI. The FGA provides clinicians with a single tool to utilize across a variety of neurologic diagnoses.

Assessment of the Shank-to-Vertical Angle While Changing Heel Heights Using a Single Inertial Measurement Unit in Individuals with Incomplete Spinal Cord Injury Wearing an Ankle-Foot-Orthosis

Previous research showed that an Inertial Measurement Unit (IMU) on the anterior side of the shank can accurately measure the Shank-to-Vertical Angle (SVA), which is a clinically-used parameter to guide tuning of ankle-foot orthoses (AFOs). However, in this context it is specifically important that differences in the SVA are detected during the tuning process, i.e., when adjusting heel height. This study investigated the validity of the SVA as measured by an IMU and its responsiveness to changes in AFO-footwear combination (AFO-FC) heel height in persons with incomplete spinal cord injury (iSCI). Additionally, the effect of heel height on knee flexion-extension angle and internal moment was evaluated. Twelve persons with an iSCI walked with their own AFO-FC in three different conditions: (1) without a heel wedge (refHH), (2) with 5 mm heel wedge (lowHH) and (3) with 10 mm heel wedge (highHH). Walking was recorded by a single IMU on the anterior side of the shank and a 3D gait analysis (3DGA) simultaneously. To estimate validity, a paired t-test and intraclass correlation coefficient (ICC) between the SVA_IMU and SVA_3DGA were calculated for the refHH. A repeated measures ANOVA was performed to evaluate the differences between the heel heights. A good validity with a mean difference smaller than 1 and an ICC above 0.9 was found for the SVA during midstance phase and at midstance. Significant differences between the heel heights were found for changes in SVA_IMU (p = 0.036) and knee moment (p = 0.020) during the midstance phase and in SVA_IMU (p = 0.042) and SVA_3DGA (p = 0.006) at midstance. Post-hoc analysis revealed a significant difference between the ref and high heel height condition for the SVA_IMU (p = 0.005) and knee moment (p = 0.006) during the midstance phase and for the SVA_IMU (p = 0.010) and SVA_3DGA (p = 0.006) at the instant of midstance. The SVA measured with an IMU is valid and responsive to changing heel heights and equivalent to the gold standard 3DGA. The knee joint angle and knee joint moment showed concomitant changes compared to SVA as a result of changing heel height.

Hybrid Human-Machine Interface for Gait Decoding Through Bayesian Fusion of EEG and EMG Classifiers

Despite the advances in the field of brain computer interfaces (BCI), the use of the sole electroencephalography (EEG) signal to control walking rehabilitation devices is currently not viable in clinical settings, due to its unreliability. Hybrid interfaces (hHMIs) represent a very recent solution to enhance the performance of single-signal approaches. These are classification approaches that combine multiple human-machine interfaces, normally including at least one BCI with other biosignals, such as the electromyography (EMG). However, their use for the decoding of gait activity is still limited. In this work, we propose and evaluate a hybrid human-machine interface (hHMI) to decode walking phases of both legs from the Bayesian fusion of EEG and EMG signals. The proposed hHMI significantly outperforms its single-signal counterparts, by providing high and stable performance even when the reliability of the muscular activity is compromised temporarily (e.g., fatigue) or permanently (e.g., weakness). Indeed, the hybrid approach shows a smooth degradation of classification performance after temporary EMG alteration, with more than 75% of accuracy at 30% of EMG amplitude, with respect to the EMG classifier whose performance decreases below 60% of accuracy. Moreover, the fusion of EEG and EMG information helps keeping a stable recognition rate of each gait phase of more than 80% independently on the permanent level of EMG degradation. From our study and findings from the literature, we suggest that the use of hybrid interfaces may be the key to enhance the usability of technologies restoring or assisting the locomotion on a wider population of patients in clinical applications and outside the laboratory environment.

Targeted Walking in Incomplete Spinal Cord Injury: Role of Corticospinal Control

Locomotor recovery after incomplete spinal cord injury (iSCI) is influenced by spinal and supraspinal networks. Conventional clinical gait analysis fails to differentiate between these components. There is evidence that corticospinal control is enhanced during targeted walking, where each foot must be continuously placed on visual targets in randomized order. This study investigates the potential of targeted walking in the functional assessment of corticospinal integrity. Twenty-one controls and 16 individuals with chronic iSCI performed normal and targeted walking on a treadmill while electromyograms (EMGs) and kinematics were recorded. Precision (% of accurate foot placements) in targeted walking was significantly lower in individuals with iSCI (82.9 ± 14.7%, controls: 94.9 ± 4.0%). Although the overall kinematic pattern was comparable between walking conditions, controls showed significantly higher semitendinosus (ST) activity before heel-strike during targeted walking. This was accompanied by a shift of relative EMG intensity from 90-120 Hz to lower frequencies of 20-60 Hz, previously associated with corticospinal control of muscle activity. Targeted walking in individuals with iSCI evoked smaller EMG changes, suggesting that the switch to more corticospinal control is impaired. Accordingly, mildly impaired iSCI individuals revealed higher adaptations to the targeted walking task than more-impaired individuals. Recording of EMGs during targeted walking holds potential as a research tool to reveal further insights into the neuromuscular control of locomotion. It also complements findings of pre-clinical studies and is a promising novel surrogate marker of integrity of corticospinal control in individuals with iSCI and other neurological impairments. Future studies should investigate its potential for diagnosis or tracking recovery during rehabilitation.

Postural control strategy after incomplete spinal cord injury: effect of sensory inputs on trunk-leg movement coordination

BACKGROUND

Postural control is affected after incomplete spinal cord injury (iSCI) due to sensory and motor impairments. Any alteration in the availability of sensory information can challenge postural stability in this population and may lead to a variety of adaptive movement coordination patterns. Hence, identifying the underlying impairments and changes to movement coordination patterns is necessary for effective rehabilitation post-iSCI. This study aims to compare the postural control strategy between iSCI and able-bodied populations by quantifying the trunk-leg movement coordination under conditions that affects sensory information.

METHODS

13 individuals with iSCI and 14 aged-matched able-bodied individuals performed quiet standing on hard and foam surfaces with eyes open and closed. We used mean Magnitude-Squared Coherence between trunk-leg accelerations measured by accelerometers placed over the sacrum and tibia.

RESULTS

We observed a similar ankle strategy at lower frequencies (f ≤ 1.0 Hz) between populations. However, we observed a decreased ability post-iSCI in adapting inter-segment coordination changing from ankle strategy to ankle-hip strategy at higher frequencies (f > 1.0 Hz). Moreover, utilizing the ankle-hip strategy at higher frequencies was challenged when somatosensory input was distorted, whereas depriving visual information did not affect balance strategy.

CONCLUSION

Trunk-leg movement coordination assessment showed sensitivity, discriminatory ability, and excellent test-retest reliability to identify changes in balance control strategy post-iSCI and due to altered sensory inputs. Trunk-leg movement coordination assessment using wearable sensors can be used for objective outcome evaluation of rehabilitative interventions on postural control post-iSCI.

Influence of Body Weight Support Systems on the Abnormal Gait Kinematic

In recent years, the Body Weight Support system has been considered to be an indispensable component in gait training systems, which be used to improve the ability to walk of hemiplegic, stroke, and spinal cord injury patients. Previous studies investigated the influence of the Body Weight Support system on gait parameters were based on the implementation with healthy subjects or patients with high assistance. Consequently, the influences of the Body Weight Support systems on gait rehabilitation in clinical practice are still unclear and need further investigation. In this study, we investigated the effects of the two Body Weight Support systems, the active body weight support system and the Counter Weight system, on an abnormal gait, which was generated by restriction of the right knee joint and 3 kg-weight on the right ankle joint. Both Body Weight Support systems improve the gait parameters of the abnormal gait such as the center of mass, the center of pressure, margin of stability, and step parameters. The active Body Weight Support system with the unloading force modulation showed more advanced and better behavior in comparison with the Counter Weight system. The results suggested the applicability of two Body Weight Support systems in clinical practice as a recovered gait intervention.

Effects of Robot-Assisted Gait Training in Individuals with Spinal Cord Injury: A Meta-analysis

Background

To investigate the effects of robot-assisted gait training (RAGT) on spasticity and pain in people with spinal cord injury (SCI). Material and methods. Four electronic databases (PubMed, Scopus, Medline, and Cochrane Central Register of Controlled Trials) were searched for studies published up to November 2019. Only human trials and of English language were included. The searched studies were reviewed and extracted independently by two authors. Randomized controlled trials (RCTs) and non-RCTs were pooled separately for analyses. Primary outcome measures included spasticity assessed by Ashworth scale (AS) or modified Ashworth scale (MAS) and pain assessed by VAS. Secondary outcome measures included lower extremity motor score (LEMS) and walking ability (i.e., 6-minute walk test, 10-meter walk test).

Results

A total of 225 studies were identified. Eighteen studies (7 RCTs and 11 non-RCTs) including 301 subjects met inclusion criteria. The outcome measure of spasticity significantly improved in favor of RAGT group in non-RCTs (AS: 95%CI = −0.202 to -0.068, p ≤ 0.001; MAS: 95%CI = −2.886 to -1.412, p ≤ 0.001). The results on pain did not show significant change after RAGT in either RCTs or non-RCTs. LEMS and walking ability significantly increased in favor of RAGT.

Conclusions

RAGT can improve spasticity and walking ability in people with SCI. The probable reason for no significant change in pain after RAGT is floor effect. RAGT is beneficial for normalizing muscle tone and for improving lower extremity function in people with SCI without causing extra pain.

van Asseldonk EH. Automatic versus manual tuning of robot-assisted gait training in people with neurological disorders

BACKGROUND

In clinical practice, therapists choose the amount of assistance for robot-assisted training. This can result in outcomes that are influenced by subjective decisions and tuning of training parameters can be time-consuming. Therefore, various algorithms to automatically tune the assistance have been developed. However, the assistance applied by these algorithms has not been directly compared to manually-tuned assistance yet. In this study, we focused on subtask-based assistance and compared automatically-tuned (AT) robotic assistance with manually-tuned (MT) robotic assistance.

METHODS

Ten people with neurological disorders (six stroke, four spinal cord injury) walked in the LOPES II gait trainer with AT and MT assistance. In both cases, assistance was adjusted separately for various subtasks of walking (in this study defined as control of: weight shift, lateral foot placement, trailing and leading limb angle, prepositioning, stability during stance, foot clearance). For the MT approach, robotic assistance was tuned by an experienced therapist and for the AT approach an algorithm that adjusted the assistance based on performances for the different subtasks was used. Time needed to tune the assistance, assistance levels and deviations from reference trajectories were compared between both approaches. In addition, participants evaluated safety, comfort, effect and amount of assistance for the AT and MT approach.

RESULTS

For the AT algorithm, stable assistance levels were reached quicker than for the MT approach. Considerable differences in the assistance per subtask provided by the two approaches were found. The amount of assistance was more often higher for the MT approach than for the AT approach. Despite this, the largest deviations from the reference trajectories were found for the MT algorithm. Participants did not clearly prefer one approach over the other regarding safety, comfort, effect and amount of assistance.

CONCLUSION

Automatic tuning had the following advantages compared to manual tuning: quicker tuning of the assistance, lower assistance levels, separate tuning of each subtask and good performance for all subtasks. Future clinical trials need to show whether these apparent advantages result in better clinical outcomes.

Utilizing three dimensional clinical gait analysis to optimize mobility outcomes in incomplete spinal cord damage

BACKGROUND

Three-dimensional gait analysis (3DGA) has not previously been considered by consensus panels of spinal cord experts for use in studies of patients with spinal cord damage (SCD), yet it is frequently used in other neurological populations, such as stroke and cerebral palsy.

RESEARCH QUESTION

How does 3DGA impairment based reporting guide individualised clinical decision-making in people with incomplete SCD?

METHODS

Retrospective open cohort case series recruited 48 adults with incomplete SCD (traumatic or non-traumatic spinal cord dysfunction) referred to the Clinical Gait Analysis Service (CGAS), Melbourne, Australia. Three-dimensional gait data were used to identify gait impairments by the multidisciplinary clinical team. Gait patterns were classified using the plantarflexor-knee extension couple index and the Gait Profile Score (GPS). The reason for referral and the recommendations made post-3DGA were collated in decision trees to extrapolate the potential value of 3DGA in decision making for targeted intervention in this population.

RESULTS

Participants with SCD generally walked at a reduced gait speed. When grouped by neurological level, the tetraplegia group had a significantly lower GPS, but no specific gait patterns emerged. Participants were primarily referred to the CGAS to direct clinical intervention decisions. The most frequent recommendation following 3DGA was the prescription of an ankle foot orthosis and in some cases, the recommendation was incongruent with the referrer's proposed intervention.

SIGNIFICANCE

3DGA can provide specific guidance in management plans for gait of patients with incomplete SCD and may help to avoid inappropriate or unnecessary interventions. This sample of patients referred to the CGAS demonstrates its clinical utility in guiding clinicians in their decision making to target individualised intervention.

Walking Function After Cervical Contusion and Distraction Spinal Cord Injuries in Rats

This study examines and compares the walking function in contusion and distraction spinal cord injury (SCI) mechanisms. Moderate contusion and distraction SCIs were surgically induced between C5 and C6 in Sprague-Dawley male rats. The CatWalk system was used to perform gait analysis of walkway walking. The ladder rung walking test was used to quantify skilled locomotor movements of ladder rung walking. It was found that the inter-paw coordination, paw support, front paw kinematics, hind paw kinematics, and skilled movements were significantly different before and after contusion and distraction. Step sequence duration, diagonal support, forelimb intensity, forelimb duty cycle, forelimb paw angle, and forelimb swing speed were more greatly affected in distraction than in contusion at 2 weeks post-injury, whereas hindlimb stand was more greatly affected in contusion than in distraction at 8 weeks post-injury. After 8 weeks post-injury, diagonal coupling-variation, girdle coupling-variation, ipsilateral coupling-mean, forelimb maximum contact at, forelimb intensity, forelimb paw angle, and number of forelimb misplacements recovered to normal in contusion but not in distraction, whereas step sequence duration, ipsilateral coupling-variation, forelimb stand, forelimb duty cycle, hindlimb swing duration, hindlimb swing speed, and number of forelimb slips recovered to normal in distraction but not in contusion. Some of the behavioral outcomes, but not the others, were linearly correlated with the histological outcomes. In conclusion, walking deficits and recovery can be affected by the type of common traumatic SCI.

Error variability affects the after effects following motor learning of lateral balance control during walking in people with spinal cord injury

People with incomplete spinal cord injury (iSCI) usually show impairments in lateral balance control during walking. Effective interventions for improving balance control are still lacking, probably due to limited understanding of motor learning mechanisms. The objective of this study was to determine how error size and error variability impact the motor learning of lateral balance control during walking in people with iSCI. Fifteen people with iSCI were recruited. A controlled assistance force was applied to the pelvis in the medial-lateral direction using a customized cable-driven robotic system. Participants were tested using 3 conditions, including abrupt, gradual, and varied forces. In each condition, participants walked on a treadmill with no force for 1 min (baseline), with force for 9 min (adaptation), and then with no force for additional 2 min (post-adaptation). The margin of stability at heel contact (MoS_HC) and minimum value moment (MoS_Min) were calculated to compare the learning effect across different conditions. Electromyogram signals from the weaker leg were also collected. Participants showed an increase in MoS_Min (after effect) following force release during the post-adaptation period for all three conditions. Participants showed a faster adaptation and a shorter lasting of after effect in MoS_Min for the varied condition in comparison with the gradual and abrupt force conditions. Increased error variability may facilitate motor learning in lateral balance control during walking in people with iSCI, although a faster learning may induce a shorter lasting of after effect. Error size did not show an impact on the lasting of after effect.

Mobility related physical and functional losses due to aging and disease - a motivation for lower limb exoskeletons

BACKGROUND

Physical and functional losses due to aging and diseases decrease human mobility, independence, and quality of life. This study is aimed at summarizing and quantifying these losses in order to motivate solutions to overcome them with a special focus on the possibilities by using lower limb exoskeletons.

METHODS

A narrative literature review was performed to determine a broad range of mobility-related physical and functional measures that are affected by aging and selected cardiovascular, respiratory, musculoskeletal, and neurological diseases.

RESULTS

The study identified that decreases in limb maximum muscle force and power (33% and 49%, respectively, 25-75 yrs) and in maximum oxygen consumption (40%, 20-80 yrs) occur for older adults compared to young adults. Reaction times more than double (18-90 yrs) and losses in the visual, vestibular, and somatosensory systems were reported. Additionally, we found decreases in steps per day (75%, 60-85 yrs), maximum walking speed (24% 25-75 yrs), and maximum six-minute and self-selected walking speed (38% and 21%, respectively, 20-85 yrs), while we found increases in the number of falls relative to the number of steps per day (800%), injuries due to falls (472%, 30-90 yrs) and deaths caused by fall (4000%, 65-90 yrs). Measures were identified to be worse for individuals with impaired mobility. Additional detrimental effects identified for them were the loss of upright standing and locomotion, freezing in movement, joint stress, pain, and changes in gait patterns.

DISCUSSION

This review shows that aging and chronic conditions result in wide-ranging losses in physical and sensory capabilities. While the impact of these losses are relatively modest for level walking, they become limiting during more demanding tasks such as walking on inclined ground, climbing stairs, or walking over longer periods, and especially when coupled with a debilitating disease. As the physical and functional parameters are closely related, we believe that lost functional capabilities can be indirectly improved by training of the physical capabilities. However, assistive devices can supplement the lost functional capabilities directly by compensating for losses with propulsion, weight support, and balance support.

CONCLUSIONS

Exoskeletons are a new generation of assistive devices that have the potential to provide both, training capabilities and functional compensation, to enhance human mobility.

Effects of Two Different Hip-Knee-Ankle-Foot Orthoses on Postural Stability in Subjects with Spinal Cord Injury: A Pilot Study

Study Design

Pilot study.

Purpose

Evaluation of two different hip-knee-ankle-foot orthoses (HKAFOs; medial linkage reciprocating gait orthosis [MLRGO] and isocentric reciprocating gait orthosis [IRGO]) using gait and postural stability analysis in four subjects with spinal cord injury (SCI).

Overview of Literature

To the best of our knowledge, no study has evaluated postural stability in subjects with SCI when using MLRGO and IRGO.

Methods

The relative efficacy of each orthosis was evaluated with relevant gait parameters, and an assessment of postural stability and sway during usage was made. Each analysis was conducted following an appropriate period of training and acclimatization. The gait parameters employed in the study were walking speed, cadence, and endurance; these were recorded and analyzed using current, validated methods. Postural stability was assessed using a verified force plate measurement system, and a modified Falls Efficacy Scale (mFES) was used for the measurement of postural sway and the perceived fear of falling.

Results

Walking speed, cadence, and endurance increased with the use of both HKAFOs. When the two types of HKAFOs were compared, all the parameters showed a slight (but not significant) increase with the use of MLRGO compared with the use of IRGO. In contrast, there were slight but insignificant improvements in postural sway with the use of IRGO. However, although there were no significant differences between the two sets of mFES scores, there was a slightly reduced fear of falling with the use of MLRGO compared with the use of IRGO in the static standing position.

Conclusions

It is noteworthy that meaningful interpretations of results can only be drawn if a larger sample is employed. This pilot study showed no significant data; however, the results indicate that the use of MLRGO is superior to that of IRGO in terms of potential improvement in the mobility and confidence levels of subjects with SCI.

Gait Training in Acute Spinal Cord Injury Rehabilitation-Utilization and Outcomes Among Nonambulatory Individuals: Findings From the SCIRehab Project

OBJECTIVES

To investigate the relation of gait training (GT) during inpatient rehabilitation (IPR) to outcomes of people with traumatic spinal cord injury (SCI).

DESIGN

Prospective observational study using the SCIRehab database.

SETTING

Six IPR facilities.

PARTICIPANTS

Patients with new SCI (N=1376) receiving initial rehabilitation.

INTERVENTIONS

Patients were divided into groups consisting of those who did and did not receive GT. Patients were further subdivided based on their primary mode of mobility as measured by the FIM.

MAIN OUTCOME MEASURES

Pain rating scales, Patient Health Questionnaire Mood Subscale, Satisfaction With Life Scale, and Craig Handicap Assessment and Reporting Technique (CHART).

RESULTS

Nearly 58% of all patients received GT, including 33.3% of patients who were primarily using a wheelchair 1 year after discharge from IPR. Those who used a wheelchair and received GT, received significantly less transfer and wheeled mobility training (P<.001). CHART physical independence (P=.002), mobility (P=.024), and occupation (P=.003) scores were significantly worse in patients who used a wheelchair at 1 year and received GT, compared with those who used a wheelchair and did not receive GT in IPR. Older age was also a significant predictor of worse participation as measured by the CHART.

CONCLUSIONS

A significant percentage of individuals who are not likely to become functional ambulators are spending portions of their IPR stays performing GT, which is associated with less time allotted for other functional interventions. GT in IPR was also associated with participation deficits at 1 year for those who used a wheelchair, implying the potential consequences of opportunity costs, pain, and psychological difficulties of receiving unsuccessful GT. Clinicians should consider these data when deciding to implement GT during initial IPR.

The Myosuit: Bi-articular Anti-gravity Exosuit That Reduces Hip Extensor Activity in Sitting Transfers

Muscle weakness-which can result from neurological injuries, genetic disorders, or typical aging-can affect a person's mobility and quality of life. For many people with muscle weakness, assistive devices provide the means to regain mobility and independence. These devices range from well-established technology, such as wheelchairs, to newer technologies, such as exoskeletons and exosuits. For assistive devices to be used in everyday life, they must provide assistance across activities of daily living (ADLs) in an unobtrusive manner. This article introduces the Myosuit, a soft, wearable device designed to provide continuous assistance at the hip and knee joint when working with and against gravity in ADLs. This robotic device combines active and passive elements with a closed-loop force controller designed to behave like an external muscle (exomuscle) and deliver gravity compensation to the user. At 4.1 kg (4.6 kg with batteries), the Myosuit is one of the lightest untethered devices capable of delivering gravity support to the user's knee and hip joints. This article presents the design and control principles of the Myosuit. It describes the textile interface, tendon actuators, and a bi-articular, synergy-based approach for continuous assistance. The assistive controller, based on bi-articular force assistance, was tested with a single subject who performed sitting transfers, one of the most gravity-intensive ADLs. The results show that the control concept can successfully identify changes in the posture and assist hip and knee extension with up to 26% of the natural knee moment and up to 35% of the knee power. We conclude that the Myosuit's novel approach to assistance using a bi-articular architecture, in combination with the posture-based force controller, can effectively assist its users in gravity-intensive ADLs, such as sitting transfers.

A generalized framework to achieve coordinated admittance control for multi-joint lower limb robotic exoskeleton

Traditional joint space admittance controller for N-DOF robotic systems is complexity and easily leads to incongruous movement among all joints. Our study introduces a central pattern generator (CPG) network into one-dimension joint space admittance control for the custom-made lower limb robotic exoskeleton with four DOFs, to guarantee the coordinated movement and security of users. The predefined trajectories for four joints are produced by CPG. Unilateral knee joint torque of subjects is detected based on corresponding muscle EMG signals. The torque is transformed into an additional set of state variables for CPG based on the one-dimension admittance controller. CPG harmonically adjusts the predefined trajectories by the additional state variables. Finally, the robotic exoskeleton completes the predefined trajectories with a classical PID controller.

The Human Central Pattern Generator for Locomotion: Does It Exist and Contribute to Walking?

The ability of dedicated spinal circuits, referred to as central pattern generators (CPGs), to produce the basic rhythm and neural activation patterns underlying locomotion can be demonstrated under specific experimental conditions in reduced animal preparations. The existence of CPGs in humans is a matter of debate. Equally elusive is the contribution of CPGs to normal bipedal locomotion. To address these points, we focus on human studies that utilized spinal cord stimulation or pharmacological neuromodulation to generate rhythmic activity in individuals with spinal cord injury, and on neuromechanical modeling of human locomotion. In the absence of volitional motor control and step-specific sensory feedback, the human lumbar spinal cord can produce rhythmic muscle activation patterns that closely resemble CPG-induced neural activity of the isolated animal spinal cord. In this sense, CPGs in humans can be defined by the activity they produce. During normal locomotion, CPGs could contribute to the activation patterns during specific phases of the step cycle and simplify supraspinal control of step cycle frequency as a feedforward component to achieve a targeted speed. Determining how the human CPGs operate will be essential to advance the theory of neural control of locomotion and develop new locomotor neurorehabilitation paradigms.

Intermittent Hypoxia and Locomotor Training Enhances Dynamic but Not Standing Balance in Patients With Incomplete Spinal Cord Injury

OBJECTIVE

To test the effect of combined intermittent hypoxia (IH) and body weight-supported treadmill training (BWSTT) on standing and dynamic balance in persons with incomplete spinal cord injury (iSCI).

DESIGN

Randomized, triple-blind, placebo-controlled study.

SETTING

Rehabilitation medical centers.

PARTICIPANTS

Study participants (N=35) with chronic iSCI with American Spinal Injury Association grades C and D (>1y postinjury) were randomly assigned to either IH plus BWSTT (n=18) or continued normoxia (placebo) plus BWSTT protocol (n=17).

INTERVENTIONS

Participants received either IH (alternating 1.5min 9% inspired O₂ with 1.5min 21% inspired O₂, 15 cycles per day) or continued normoxia (21% O₂) combined with 45 minutes of BWSTT for 5 consecutive days, followed by 3 times per week IH or normoxia plus BWSTT, for 3 additional weeks.

MAIN OUTCOME MEASURES

Standing balance (normalized jerk and root-mean-square [RMS]) and dynamic balance (turning duration, cadence in a turn, and turn-to-sit duration) were assessed before and after IH and normoxia protocol by means of instrumented sway and instrumented timed Up and Go test.

RESULTS

There was no significant difference in standing balance between interventions for both normalized jerk and RMS instrumented sway components (both P>.05). There was a significantly faster cadence (P<.001), turning duration (P<.001), and turn-to-sit duration (P=.001) in subjects receiving IH plus BWSTT, compared with placebo.

CONCLUSIONS

A 4-week protocol of IH combined with locomotor training improves dynamic, but not standing, balance in persons with iSCI.

Ambulation following spinal cord injury and its correlates

Objectives:

To assess walking ability of spinal cord injury (SCI) patients and observe its correlation with functional and neurological outcomes.

Patients and Methods:

The present prospective, observational study was conducted in a tertiary research hospital in India with 66 patients (46 males) between January 2012 and December 2013. Mean age was 32.62 ± 11.85 years (range 16-65 years), mean duration of injury was 85.3 ± 97.6 days (range 14-365 days) and mean length of stay in the rehabilitation unit was 38.08 ± 21.66 days (range 14-97 days) in the study. Walking Index for spinal cord injury (WISCI II) was used to assess ambulation of the SCI patients. Functional recovery was assessed using Barthel Index (BI) and Spinal Cord Independence Measures (SCIM). Neurological recovery was assessed using ASIA impairment scale (AIS). We tried to correlate ambulatory ability of the patients with functional and neurological recovery.

Results:

Ambulatory ability of the patients improved significantly using WISCI II (P < 0.001) when admission and discharge scores were compared (1.4 ± 3.5 vs 7.6 ± 6.03). Similarly, functional (BI: 31.7 ± 20.5 vs 58.4 ± 23.7 and SCIM: 29.9 ± 15.1 vs 56.2 ± 20.6) and neurological recovery were found to be very significant (P < 0.001) when admission vs discharge scores were compared. Improvement in WISCI II scores was significantly correlated with improvement in neurological (using AIS scores) and functional status (using BI and SCIM scores) (P < 0.001).

Conclusions:

Significant improvement was seen in WISCI II, BI, and SCIM scores after in-patient rehabilitation. Improvement in WISCI II scores also significantly correlated with functional and neurological recovery.

Posture Influence on the Pendulum Test of Spasticity in Patients with Spinal Cord Injury

The study aims to investigate the influence of different postures on spasticity results by pendulum test in patients with spinal cord injury (SCI). The setting was at the University of Campinas (UNICAMP), Campinas, SP, Brazil. Five individuals with SCI and five individuals in the control group were included. All individuals went through the pendulum test in three different positions: supine, semi-supine at an angle of 30°, and sitting up at an angle of 60°. An electrogoniometer was attached to the right leg for measurement of knee joint angles. All situations were performed five times. Blood pressure was monitored during tests. Relaxation index (RI), normalized relaxation index (RIn), test duration in seconds, initial flexion angle, and resting angle were analyzed at three different positions. Results were compared between different positions, and statistically no differences were found. In individuals with SCI, RI (1.83 ± 0.2), RIn (1.14 ± 0.13), and test duration values (13.95 ± 4.14), in sitting up position, were similar to the control group results. In sitting up position, patients showed spasticity reduction. However, the other two postures produce pain and increase blood pressure in patients with tetraplegia. Therefore, these postures should be avoided in patients with lesions above T6, due to possible autonomic dysreflexia symptoms.

Effects of spinal cord injury-induced changes in muscle activation on foot drag in a computational rat ankle model

Spinal cord injury (SCI) can lead to changes in muscle activation patterns and atrophy of affected muscles. Moderate levels of SCI are typically associated with foot drag during the swing phase of locomotion. Foot drag is often used to assess locomotor recovery, but the causes remain unclear. We hypothesized that foot drag results from inappropriate muscle coordination preventing flexion at the stance-to-swing transition. To test this hypothesis and to assess the relative contributions of neural and muscular changes on foot drag, we developed a two-dimensional, one degree of freedom ankle musculoskeletal model with gastrocnemius and tibialis anterior muscles. Anatomical data collected from sham-injured and incomplete SCI (iSCI) female Long-Evans rats as well as physiological data from the literature were used to implement an open-loop muscle dynamics model. Muscle insertion point motion was calculated with imposed ankle trajectories from kinematic analysis of treadmill walking in sham-injured and iSCI animals. Relative gastrocnemius deactivation and tibialis anterior activation onset times were varied within physiologically relevant ranges based on simplified locomotor electromyogram profiles. No-atrophy and moderate muscle atrophy as well as normal and injured muscle activation profiles were also simulated. Positive moments coinciding with the transition from stance to swing phase were defined as foot swing and negative moments as foot drag. Whereas decreases in activation delay caused by delayed gastrocnemius deactivation promote foot drag, all other changes associated with iSCI facilitate foot swing. Our results suggest that even small changes in the ability to precisely deactivate the gastrocnemius could result in foot drag after iSCI.

Gait recovery in a girl with ischemic spinal cord stroke

BACKGROUND AND PURPOSE

This case report describes an aggressive, task-specific program for the recovery of gait in a girl with a spinal cord stroke.

CASE DESCRIPTION

The 11-year-old girl sustained a spinal cord stroke resulting in a T4 motor-incomplete lesion. Therapy was initiated 6 months after onset when she was not ambulating.

INTERVENTION

The focus of all interventions was on the restoration of gait. Locomotor treadmill training and over ground walking were the primary practice interventions. Walking was facilitated by orthoses, neuromuscular electrical stimulation, laser treatments, and strengthening. Treatment continued for 18 months.

OUTCOMES

At the conclusion of therapy, the client was able to walk independently in the community with a single ankle foot orthosis and reverse rolling walker.

DISCUSSION

The outcome was not anticipated for this client, given the type and level of her injury and the delay in starting gait training.

Thinking through every step: how people with spinal cord injuries relearn to walk

In this article we explore how people with incomplete spinal cord injury (iSCI) create meaning out of their changing bodies as they undergo a therapeutic intervention called locomotor training (LT). Therapeutic interventions like LT are used to promote the recovery of walking ability among individuals with iSCI. The chronological nature of this study--interviews at three points throughout the 12-week intervention--enhances understanding of the recovering self after spinal cord injury. Drawing on a constructivist theoretical framework, we organize data according to three narrative frames. Participants interpreted LT as (a) a physical change that was meaningful because of its social significance, (b) a coping strategy for dealing with the uncertainty of long-term recovery, and (c) a moral strategy to reconstitute the self. We offer findings that lay the conceptual groundwork for generating new knowledge about what is important to people with iSCI as they relearn how to walk.

Detection of abnormal muscle activations during walking following spinal cord injury (SCI)

In order to identify optimal rehabilitation strategies for spinal cord injury (SCI) participants, assessment of impaired walking is required to detect, monitor and quantify movement disorders. In the proposed assessment, ten healthy and seven SCI participants were recruited to perform an over-ground walking test at slow walking speeds. SCI participants were given assistance from physiotherapists, if required, while they were walking. In agreement with other research, larger cadence and smaller step length and swing phase of SCI gait were observed as a result of muscle weakness and resultant gait instability. Muscle activation patterns of seven major leg muscles were collected. The EMG signal was processed by the RMS in frequency domain to represent the muscle activation power, and the distribution of muscle activation was compared between healthy and SCI participants. The alternations of muscle activation within the phases of the gait cycle are highlighted to facilitate our understanding of the underlying muscular activation following SCI. Key differences were observed (p-value=0.0006) in the reduced activation of tibialis anterior (TA) in single stance phase and rectus femoris (RF) in swing phase (p-value=0.0011). We can then conclude that the proposed assessment approach of gait provides valuable information that can be used to target and define therapeutic interventions and their evaluation; hence impacting the functional outcome of SCI individuals.

Comparison of the effects of solid versus hinged ankle foot orthoses on select temporal gait parameters in patients with incomplete spinal cord injury during treadmill walking

BACKGROUND

Ankle foot orthoses (AFOs) are usually used for patients with incomplete spinal cord injury (ISCI) to provide support in walking.

OBJECTIVES

The aim of this study was to compare the effect of AFOs, with and without ankle hinges, on specific gait parameters during treadmill training by subjects with ISCI.

STUDY DESIGN

Quasi-experimental.

METHODS

Five patients with ISCI at the thoracic level participated in this study. Gait evaluation was performed when walking 1) barefoot 2) wearing a solid AFO and 3) wearing a hinged AFO.

RESULTS

The mean step length when walking barefoot was 26.3 ± 16.37 cm compared to 31.3 ± 17.27 cm with a solid AFO and 28.5 ± 15.86 cm with a hinged AFO. The mean cadence for walking barefoot was 61.59 ± 25.65 steps/min. compared to 50.94 ± 22.36 steps/min. with a solid AFO and 56.25 ± 24.44 steps/min with a hinged AFO. Significant differences in cadence and step length during walking were only demonstrated between the barefoot condition and when wearing a solid AFO. Significant difference was not observed between conditions in mean of ankle range of motion.

CONCLUSION

The solid AFO was the only condition which improved cadence and step length in patients during ISCI gait training. Clinical relevance A solid AFO could be used permanently to compensate for impaired ankle function or it could be used while retraining stepping.

Adaptive robotic rehabilitation of locomotion: a clinical study in spinally injured individuals

STUDY DESIGN

Clinical study on six spinal cord-injured subjects. The performance of two automatic gait-pattern adaptation algorithms for automated treadmill training rehabilitation of locomotion (called DJATA1 and DJATA2) was tested and compared in this study.

OBJECTIVES

To test the performance of the two algorithms and to evaluate the corresponding patient satisfaction. We also wanted to evaluate the motivation of the patients to train with a fixed gait pattern versus training where they can influence and change the gait pattern (gait-pattern adaptation).

SETTING

Spinal Cord Injury Center Paracare, Balgrist, Zürich, Switzerland.

METHODS

The experimental data were collected during six blinded and randomized training trials (comprising three different conditions per algorithm) split into two training sessions per patient. During the experiments, we have recorded the time courses of the six parameters describing the adaptation. Additionally, a special patient questionnaire was developed that allowed us to collect data regarding the quality, perception, speed, and required effort of the adaptation, as well as patients' opinion that addressed their motivation. The achieved adaptation was evaluated based on the time course of adaptation parameters and based on the patient questionnaire. A statistical analysis was made in order to quantify the data and to compare the two algorithms.

RESULTS

Significant adaptation of the gait pattern took place. The patients were in most cases able to change the gait pattern to a desired one and have always perceived the adaptation. No statistically significant differences were found between the performances of the two algorithms based on the evaluated data. However, DJATA2 achieved better adaptation scores. All patients preferred treadmill training with gait-pattern adaptation.

CONCLUSION

In the future, the patients would like to train with gait-pattern adaptation. Besides the subjective opinion indicating the choice of this training modality, gait-pattern adaptation also might lead to additional improvement of the rehabilitation of locomotion as it increases and promotes active training.

SPONSORSHIP

The work was supported by The Swiss Commission for Technology and Innovation (Project No. 4005.1).

Locomotor training: as a treatment of spinal cord injury and in the progression of neurologic rehabilitation

Scientists, clinicians, administrators, individuals with spinal cord injury (SCI), and caregivers seek a common goal: to improve the outlook and general expectations of the adults and children living with neurologic injury. Important strides have already been accomplished; in fact, some have labeled the changes in neurologic rehabilitation a "paradigm shift." Not only do we recognize the potential of the damaged nervous system, but we also see that "recovery" can and should be valued and defined broadly. Quality-of-life measures and the individual's sense of accomplishment and well-being are now considered important factors. The ongoing challenge from research to clinical translation is the fine line between scientific uncertainty (ie, the tenet that nothing is ever proven) and the necessary burden of proof required by the clinical community. We review the current state of a specific SCI rehabilitation intervention (locomotor training), which has been shown to be efficacious although thoroughly debated, and summarize the findings from a multicenter collaboration, the Christopher and Dana Reeve Foundation's NeuroRecovery Network.

Changes on EMG activation in healthy subjects and incomplete SCI patients following a robot-assisted locomotor training

The aim of this study was to understand and measure the lower limbs muscular activation patterns both in healthy and spinal cord injured (SCI) subjects during robot-assisted locomotor exercise. Electromyographic (EMG) activity of four leg's muscles (rectus and biceps femoris, tibialis anterioris and gastrocnemius) was recorded and analyzed at two different percentages of body weight support, three stepping velocities and three different modalities. SCI subjects were recorded also after four weeks training to evaluate the effectiveness of lower limb robot-assisted rehabilitative treatment. A multi-factor ANOVA on the integrated muscle activity (IEMG) parameters both in healthy and SCI subjects was performed. Higher muscular activities both in healthy subjects and SCI patients were found during the exercises using the "DGO active" modality and higher stepping velocities. A significant increased bilateral muscular activity was observed in each SCI subject after the rehabilitation treatment. The method proposed to analyze EMG data provides a quantitative description of the lower limb muscular recruitment and can contribute to identify the optimal rehabilitation treatment's conditions.