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

Methods for Dynamic Balance Training During Standing and Stepping

The regaining of walking ability is one of the main goals of rehabilitation following stroke. An important aspect of bipedal locomotion is efficient balancing of the trunk. In this article a novel methodology for dynamic balance training during standing and stepping is presented in a commercially available mechanical balance training device. A case study that lasted for two-weeks with two half-hour training sessions per day, involving a single subject with chronic hemiparesis, investigated the effects of the proposed dynamic balance training. Instrumented kinesiological evaluation of the subject's gait indicated important improvement in the subject's postural control during walking. Finally, the possibility of combining therapeutic functional electrical stimulation of selected lower extremity muscles with the methodology for dynamic balance training presented here is discussed.

Effectiveness of automated locomotor training in patients with chronic incomplete spinal cord injury: A multicenter trial

OBJECTIVE

To determine whether automated locomotor training with a driven-gait orthosis (DGO) can increase functional mobility in people with chronic, motor incomplete spinal cord injury (SCI).

DESIGN

Repeated assessment of the same patients or single-case experimental A-B design.

SETTING

Research units of rehabilitation hospitals in Chicago; Heidelberg, Germany; and Basel and Zurich, Switzerland.

PARTICIPANTS

Twenty patients with a chronic (>2 y postinjury), motor incomplete SCI, classified by the American Spinal Injury Association (ASIA) Impairment Scale with ASIA grades C (n=9) and D (n=11) injury. Most patients (n=16) were ambulatory before locomotor training.

INTERVENTION

Locomotor training was provided using robotic-assisted, body-weight-supported treadmill training 3 to 5 times a week over 8 weeks. Single training sessions lasted up to 45 minutes of total walking time, with gait speed between .42 and .69 m/s and body-weight unloading as low as possible (mean +/- standard deviation, 37%+/-17%).

MAIN OUTCOME MEASURES

Primary outcome measures included the 10-meter walk test, the 6-minute walk test, the Timed Up & Go test, and the Walking Index for Spinal Cord Injury-II tests. Secondary measures included lower-extremity motor scores and spastic motor behaviors to assess their potential contribution to changes in locomotor function. All subjects were tested before, during, and after training.

RESULTS

Locomotor training using the DGO resulted in significant improvements in the subjects' gait velocity, endurance, and performance of functional tasks. There were no significant changes in the requirement of walking aids, orthoses, or external physical assistance. There was no correlation between improvements in walking speed or changes in muscle strength or spastic motor behaviors.

CONCLUSIONS

Intensive locomotor training on a treadmill with the assistance of a DGO results in improved overground walking.

Locomotor Training and Virtual Reality-based Balance Training for an Individual with Multiple Sclerosis

BACKGROUND AND PURPOSE

Impaired walking ability, balance, and fatigue are common problems for people with multiple sclerosis (MS). The purpose of this case report is to describe the use of plan of care that included locomotor training using both a body weight support (BWS) with a treadmill (TM) and overground walking as well as a virtual reality (VR)-based balance intervention to improve walking ability, balance, and endurance for an individual with MS.

CASE DESCRIPTION

The client was a 48-year-old female with a 10-year history of MS. Her main goals were to improve walking ability, balance, and endurance. She presented with impaired gait, balance, motor function, and increased fatigue. Locomotor training using a BWS/TM system and overground and VR-based balance interventions were implemented 2 days a week for 12 weeks.

OUTCOMES

The client demonstrated improvements in gait speed, gait endurance, and balance postintervention and maintained the improvements at a 2-month follow up.

DISCUSSION

This case report is the first to report on the use of locomotor training with BWS/TM system and overground and VR-based balance interventions for a client with MS. The plan of care was formulated based on the patient's goals and the available literature on the use of the interventions with other patients with neurologic conditions to provide an intervention that was task-oriented, skilled, and intensive.

Targeting recovery: priorities of the spinal cord-injured population

In the United States alone, there are more than 200,000 individuals living with a chronic spinal cord injury (SCI). Healthcare for these individuals creates a significant economic burden for the country, not to mention the physiological, psychological, and social suffering these people endure everyday. Regaining partial function can lead to greater independence, thereby improving quality of life. To ascertain what functions are most important to the SCI population, in regard to enhancing quality of life, a novel survey was performed in which subjects were asked to rank seven functions in order of importance to their quality of life. The survey was distributed via email, postal mail, the internet, interview, and word of mouth to the SCI community at large. A total of 681 responses were completed. Regaining arm and hand function was most important to quadriplegics, while regaining sexual function was the highest priority for paraplegics. Improving bladder and bowel function was of shared importance to both injury groups. A longitudinal analysis revealed only slight differences between individuals injured <3 years compared to those injured >3 years. The majority of participants indicated that exercise was important to functional recovery, yet more than half either did not have access to exercise or did not have access to a trained therapist to oversee that exercise. In order to improve the relevance of research in this area, the concerns of the SCI population must be better known and taken into account. This approach is consistent with and emphasized by the new NIH roadmap to discovery.

Long-term body-weight-supported treadmill training and subsequent follow-up in persons with chronic SCI: effects on functional walking ability and measures of subjective well-being

STUDY DESIGN

Longitudinal, prospective within-subject design.

OBJECTIVES

(1) To determine the effects of long-term body-weight-supported treadmill training (BWSTT) on functional walking ability and perceived quality of life in persons with chronic incomplete spinal cord injury (SCI), and (2) to investigate whether training adaptations are maintained following cessation of the BWSTT programme.

SETTING

Hamilton, Ontario, Canada.

METHODS

A group of 14 individuals with chronic (mean 7.4 years postinjury) incomplete SCI (ASIA B & C) participated in thrice-weekly sessions of BWSTT for a period of approximately 12 months (144 sessions). Functional walking ability and indices of subjective well-being were evaluated during the training programme and over an 8-month follow-up.

RESULTS

In total, 13 subjects successfully completed the 144 training sessions in the required study period (max. 15 months). Adherence to the thrice-weekly training frequency was 78.8%. All subjects improved in treadmill walking ability (54% reduction in required external body-weight support (BWS), 180% increase in treadmill walking speed, 335% increase in distance walked/session), and six subjects improved their capacity to walk over ground. There were accompanying increases in satisfaction with life and satisfaction with physical function, both of which were significantly correlated with improvements in treadmill walking ability. All but one subject returned for follow-up assessment 8 months post-training; while there was a slight decline in treadmill walking performance, over ground walking scores remained relatively stable. The only change in subjective well-being in the follow-up was a slight decrease in satisfaction with physical function.

CONCLUSION

Thrice-weekly BWSTT for 12 months was an effective stimulus to improve treadmill walking ability and indices of subjective well-being in persons with chronic incomplete SCI, and most of these improvements were maintained for up to 8 months following the cessation of training.

Modular transcutaneous functional electrical stimulation system

A new multipurpose programmable transcutaneous electric stimulator, Compex Motion, was developed to allow users to design various custom-made neuroprostheses, neurological assessment devices, muscle exercise systems, and experimental setups for physiological studies. Compex Motion can generate any arbitrary stimulation sequence, which can be controlled or regulated in real-time using any external sensor or laboratory equipment. Compex Motion originated from the existing Compex 2 electric stimulator, manufactured by a Swiss based company, Compex SA. The Compex Motion stimulator represents a further evolution and expansion of the ETHZ-ParaCare functional electrical stimulation system. This stimulator provides all the advanced functional electrical stimulation (FES) application and control features and can be easily incorporated into any standard rehabilitation program. Compex Motion has successfully been applied as a neuroprosthesis for walking, reaching and grasping in more than 100 stroke and spinal cord injured patients. This system has also been used to strengthen muscles and to investigate muscle properties in able-bodied subjects. Compex Motion is a multipurpose FES system specially designed to promote sharing and exchanging of stimulation protocols, sensors, and user interfaces. To the best of our knowledge an FES system that has similar capabilities does not exist yet.

Epidural spinal-cord stimulation facilitates recovery of functional walking following incomplete spinal-cord injury

We investigated a novel treatment paradigm for developing functional ambulation in wheelchair-dependent individuals with chronic, incomplete spinal-cord injury. By coordinating epidural stimulation of the dorsal structures of the spinal cord with partial weight bearing treadmill therapy, we observed improvement in treadmill and over-ground ambulation in an individual with chronic incomplete tetraplegia. The application of partial weight-bearing therapy alone was not sufficient to achieve functional ambulation over ground, though treadmill ambulation improved significantly. Combining epidural spinal-cord stimulation (ESCS, T10-T12 vertebral levels) with partial weight-bearing therapy resulted in further improvement during treadmill ambulation. Moreover, the combination of therapies facilitated the transfer of the learned gait into over ground ambulation. Performance improvements were elicited by applying continuous, charge-balanced, monophasic pulse trains at a frequency of 40-60 Hz, a pulse duration of 800 micros, and an amplitude determined by the midpoint (50%) between the sensory and motor threshold values. The participant initially reported a reduction in sense of effort for over ground walking from 8/10 to 3/10 (Borg scale), and was able to double his walking speed. After several weeks of over ground training, he reached maximum walking speeds of 0.35 m/s, and was able to ambulate over 325 m. We propose that ESCS facilitated locomotor recovery in this patient by augmenting the use-dependent plasticity created by partial weight bearing therapy. Confirmation of these promising results in a controlled study of groups of spinal-cord-injured subjects is warranted.

Locomotor activity in spinal cord-injured persons

After a spinal cord injury (SCI) of the cat or rat, neuronal centers below the level of lesion exhibit plasticity that can be exploited by specific training paradigms. In individuals with complete or incomplete SCI, human spinal locomotor centers can be activated and modulated by locomotor training (facilitating stepping movements of the legs using body weight support on a treadmill to provide appropriate sensory cues). Individuals with incomplete SCI benefit from locomotor training such that they improve their ability to walk over ground. Load- or hip joint-related afferent input seems to be of crucial importance for both the generation of a locomotor pattern and the effectiveness of the training. However, it may be a critical combination of afferent signals that is needed to generate a locomotor pattern after severe SCI. Mobility of individuals after a SCI can be improved by taking advantage of the plasticity of the central nervous system and can be maintained with persistent locomotor activity. In the future, if regeneration approaches can successfully be applied in human SCI, even individuals with complete SCI may recover walking ability with locomotor training.

Functional electric stimulation to augment partial weight-bearing supported treadmill training for patients with acute incomplete spinal cord injury: a pilot study

OBJECTIVE

To study the application of partial weight-bearing (PWB) supported treadmill gait training augmented by functional electric stimulation (FES) in subjects with acute incomplete spinal cord injury (SCI).

DESIGN

Before-after crossover trial with control (A) and intervention (B) periods.

SETTING

Physiotherapy (PT) department of a spinal injuries unit in Scotland.

PARTICIPANTS

Fourteen inpatients with acute incomplete SCI with American Spinal Injury Association class C or D injury.

INTERVENTION

Training consisted of treadmill walking with PWB support augmented by FES. Subjects walked on the treadmill for up to 25 minutes a day, 5 days a week for 4 weeks. The intervention was compared with a 4-week control period in which standard PT was given.

MAIN OUTCOME MEASURES

Overground walking endurance and speed, cadence, stride length, and observational gait analysis and walking speed, distance, and percentage PWB support on the treadmill.

RESULTS

A greater increase in overground walking endurance was achieved after the intervention (AB group mean, 72.2m; confidence interval [CI], 39.8-104.6m; BA group mean, 63.8m; CI, -10.2 to 137.9m), as compared with after standard PT (AB group mean, 38.4m; CI, 1.8-75.0m; BA group mean, 60.1m; CI, 9.2-110.9m). A similar pattern was observed for overground walking speed.

CONCLUSIONS

This pilot study indicated that PWB supported treadmill training with FES had a positive effect on overground gait parameters and could potentially accelerate gait training in subjects with incomplete SCI. A larger randomized trial is required to substantiate these findings.

Electromechanical gait training with functional electrical stimulation: case studies in spinal cord injury

STUDY DESIGN

Single case studies.

OBJECTIVES

To describe the technique of intensive locomotor training on an electromechanical gait trainer (GT) combined with functional electrical stimulation (FES).

SETTING

Neurological Rehabilitation Clinic, Berlin, Germany.

METHODS

Four spinal cord-injured (SCI) patients, one tetraparetic, two paraparetic, and one patient with an incomplete cauda syndrome, more than 3 months postinjury, who were unable to walk at all, or with two therapists. They received 25 min of locomotor training on the GT plus FES daily for 5 weeks in addition to the regular therapy.

RESULTS

The patients tolerated the programme well, and therapists rated the programme less strenuous compared to manually assisted treadmill training. Gait ability improved in all four patients; three patients could walk independently on the floor with the help of technical aids, and one required the help of one therapist after therapy; gait speed and endurance more than doubled, and the gastrocnemius activity increased in the patients with a central paresis.

CONCLUSION

This combined technique allows intensive locomotor therapy in SCI subjects with reduced effort from the therapists. The patients' improved walking ability confirmed the potential of locomotor therapy in SCI subjects.

Induction of locomotor-like EMG activity in paraplegic persons by orthotic gait training

This is, to our knowledge, the first report demonstrating the effects of orthotic gait training on the activity of the spinal locomotor neural networks. Three subjects with complete spinal cord injury (SCI) performed 1-h training with reciprocating gait orthosis 5 days/week for 12 weeks. The results showed that after 3 (n=1) or 6 weeks (n=2) of training, EMG activities synchronized with locomotor rhythm appeared in the soleus muscle (SOL) in all subjects, although very little EMG activity accompanied the orthotic gait at the early training stage. Our results suggest that the induced modulation in the SOL EMG waveforms might be attributable to changes in the orthotic gait movement pattern, and/or changes in the interneuronal activities of the spinal locomotor neural networks, as a result of orthotic gait training.

Temporal patterns of plantar pressures and lower-leg muscle activity during walking: effect of speed

Plantar pressure assessment is a tool useful for study of the gait cycle. In this study, we present a means of assessing the gait cycle using a temporal analysis of plantar pressures and lower-leg muscle activities. Plantar pressures and surface electromyography (EMG) of the tibialis anterior (TA) and medial gastrocnemius (MG) muscles were recorded as 19 men walked on a treadmill at seven speeds between 0.45 and 1.79 m/s. A typical 'heel strike to toe off' gait pattern was observed. Speed had minimal effects on the shapes of the muscle EMG root-mean-square-and plantar pressure-time curves except for the pressure-time curves in the heel and midfoot. A linear relationship was found between speed and peak pressures in the heel, medial forefoot, and toes; pressures in these regions increased by 91-289% going from 0.45 to 1.79 m/s. The temporal pressure changes in the forefoot and toes were paralleled by changes in MG muscle activity (i.e., cross-correlations of > or =0.90); TA muscle activity was not cross-correlated with the temporal pressure patterns in any region. However, the peak values of TA muscle activity were found to be highly correlated across speeds with peak pressures in the heel and toes (i.e., r > or =0.98); similar high correlations were found between peak values of MG muscle activity and heel pressure. In summary, these data collected on able-bodied persons during motorized treadmill walking can be useful for comparison to those of patients undergoing treadmill evaluations for atypical gait cycle patterns and for tracking the progress of patients during gait rehabilitation.

It's more than a black box; it's a Russian doll: defining rehabilitation treatments

Research on treatment efficacy and effectiveness requires that the treatments of interest be objectively defined. Such definitions are relatively straightforward for pharmacologic and surgical treatments, in which the active ingredients can be specified in terms of chemical structure or anatomic result. Definitions of treatment are more difficult for the many experience-based interventions employed in rehabilitation. This has led to the criticism that much clinical rehabilitation research has characterized the treatments of interest as a "black box," allowing little insight into the active ingredients contained therein. Moreover, rehabilitation care may involve the simultaneous application of multiple different treatments, raising the question of whether to define the individual components or the service delivery system. In this article, we consider how the levels of analysis considered in rehabilitation (disease, impairment, activity, and participation) and the role of theory shape the definition of treatment, and we address the need to develop protocol-based treatments and tools to objectively verify their contents. Rigorous definition of rehabilitation treatments, supported by theory, will facilitate needed efficacy research, will allow replication of that research, and will ultimately foster dissemination of effective treatments into clinical practice.

Patterned sensory stimulation induces plasticity in reciprocal ia inhibition in humans

Training of spinal cord circuits using sensorimotor stimulation has been proposed as a strategy to improve movement after spinal injury. How sensory stimulation may lead to long-lasting changes is not well understood. We studied whether sensory stimulation might induce changes in the strength of a specific spinal interneuronal circuit: spinally mediated reciprocal Ia inhibition. In healthy humans, the strength of reciprocal inhibition between ankle flexor and extensor muscles was assessed before and after 30 min of peroneal nerve stimulation at motor threshold intensity. Three stimulation protocols were assessed: patterned nerve stimulation (10 pulses at 100 Hz every 1.5 sec), uniform nerve stimulation (one pulse every 150 msec), and combined stimulation of the peroneal nerve and the motor cortex with transcranial magnetic stimulation. Short-latency reciprocal inhibition from ankle flexor to extensor muscles was measured by conditioning the soleus H-reflex with stimulation of the common peroneal nerve. The strength of the reciprocal inhibition was measured at baseline and for 20 min after each stimulation session. Patterned stimulation, with or without motor cortex stimulation, enhanced reciprocal inhibition for at least 5 min afterward. The uniform pattern of stimulation was ineffective. These results demonstrate the presence of short-term plasticity within spinal inhibitory circuits. We conclude that the pattern of sensory input is a crucial factor for inducing changes in the spinal circuit for reciprocal inhibition in humans. These findings may have implications for the use of repetitive patterned sensory stimulation in rehabilitative efforts to improve walking ability in patients with spinal injury.

Restoring function after spinal cord injury

BACKGROUND

By affecting young people during the most productive period of their lives, spinal cord injury is a devastating problem for modern society. A decade ago, treating SCI seemed frustrating and hopeless because of the tremendous morbidity and mortality, life-shattering impact, and limited therapeutic options associated with the condition. Today, however, an understanding of the underlying pathophysiological mechanisms, the development of neuroprotective interventions, and progress toward regenerative interventions are increasing hope for functional restoration.

REVIEW SUMMARY

This study addresses the present understanding of SCI, including the etiology, pathophysiology, treatment, and scientific advances. The discussion of treatment options includes a critical review of high-dose methylprednisolone and GM-1 ganglioside therapy. The concept that limited rebuilding can provide a disproportionate improvement in quality of life is emphasized throughout.

CONCLUSIONS

New surgical procedures, pharmacologic treatments, and functional neuromuscular stimulation methods have evolved over the last decades that can improve functional outcomes after spinal cord injury, but limiting secondary injury remains the primary goal. Tissue replacement strategies, including the use of embryonic stem cells, become an important tool and can restore function in animal models. Controlled clinical trials are now required to confirm these observations. The ultimate goal is to harness the body's own potential to replace lost central nervous system cells by activation of endogenous progenitor cell repair mechanisms.

Peak exercise capacity of electrically induced ambulation in persons with paraplegia

INTRODUCTION

Persons with spinal cord injury (SCI) are generally limited to exercise activities using the relatively smaller, less productive upper extremities with limited benefits as compared with leg exercise training. Functional electrical stimulation (FES) assisted ambulation has previously been demonstrated to allow persons with paraplegia to stand and ambulate limited distances.

PURPOSE

This study compared the peak physiological responses of persons with paraplegia during FES ambulation and voluntary arm exercise.

METHODS

Fifteen subjects (T -T ) previously habituated to FES ambulation, completed peak testing of both arm cranking (AC) and FES walking to the point of exhaustion. The AC tests were performed using a graded incremental protocol to exhaustion in 3-min stages and 10-W power output increments. The FES walking test consisted of successive 10-m walking bouts, each trial progressively increased in pace. Metabolic activity was continuously monitored via open-circuit spirometry with heart rate (HR) determined by a 12-lead electrocardiograph for AC and by direct palpation during FES.

RESULTS

Peak VO(2) did not differ between AC (22.9 +/- 3.8 mL x kg x min(-1)) and FES (22.7 +/- 3.9 mL x kg x min(-1)). FES ambulation elicited significantly greater peak values of HR (191 beats x min(-1) versus 179 beats x min(-1)) and lower peak values of respiratory exchange ratio (1.06 vs 1.12) compared with AC. There were no significant differences in peak values of any other variables.

CONCLUSION

This study indicates that FES ambulation performance, in persons with paraplegia, elicits similar exercise capacity, as indicated by similar peak oxygen consumption, as voluntary arm exercise.

Late recovery following spinal cord injury. Case report and review of the literature

The authors of this prospective, single-case study evaluated the potential for functional recovery from chronic spinal cord injury (SCI). The patient was motor complete with minimal and transient sensory perception in the left hemibody. His condition was classified as C-2 American Spinal Injury Association (ASIA) Grade A and he had experienced no substantial recovery in the first 5 years after traumatic SCI. Clinical experience and evidence from the scientific literature suggest that further recovery would not take place. When the study began in 1999, the patient was tetraplegic and unable to breathe without assisted ventilation; his condition classification persisted as C-2 ASIA Grade A. Magnetic resonance imaging revealed severe injury at the C-2 level that had left a central fluid-filled cyst surrounded by a narrow donutlike rim of white matter. Five years after the injury a program known as "activity-based recovery" was instituted. The hypothesis was that patterned neural activity might stimulate the central nervous system to become more functional, as it does during development. Over a 3-year period (5-8 years after injury), the patient's condition improved from ASIA Grade A to ASIA Grade C, an improvement of two ASIA grades. Motor scores improved from 0/100 to 20/100, and sensory scores rose from 5-7/112 to 58-77/112. Using electromyography, the authors documented voluntary control over important muscle groups, including the right hemidiaphragm (C3-5), extensor carpi radialis (C-6), and vastus medialis (L2-4). Reversal of osteoporosis and an increase in muscle mass was associated with this recovery. Moreover, spasticity decreased, the incidence of medical complications fell dramatically, and the incidence of infections and use of antibiotic medications was reduced by over 90%. These improvements occurred despite the fact that less than 25 mm2 of tissue (approximately 25%) of the outer cord (presumably white matter) had survived at the injury level. The primary novelty of this report is the demonstration that substantial recovery of function (two ASIA grades) is possible in a patient with severe C-2 ASIA Grade A injury, long after the initial SCI. Less severely injured (lower injury level, clinically incomplete lesions) individuals might achieve even more meaningful recovery. The role of patterned neural activity in regeneration and recovery of function after SCI therefore appears a fruitful area for future investigation.