Hugues Barbeau

A New Approach to Retrain Gait in Stroke Patients Through Body Weight Support and Treadmill Stimulation

BACKGROUND AND PURPOSE A new gait training strategy for patients with stroke proposes to support a percentage of the patients body weight while retraining gait on a treadmill. This research project intended to compare the effects of gait training with body weight support (BWS) and with no body weight support (no-BWS) on clinical outcome measures for patients with stroke. METHODS One hundred subjects with stroke were randomized to receive one of two treatments while walking on a treadmill: 50 subjects were trained to walk with up to 40% of their body weight supported by a BWS system with overhead harness (BWS group), and the other 50 subjects were trained to walk bearing full weight on their lower extremities (no-BWS group). Treatment outcomes were assessed on the basis of functional balance, motor recovery, overground walking speed, and overground walking endurance. RESULTS After a 6-week training period, the BWS group scored significantly higher than the no-BWS group for functional balance (P = 0.001), motor recovery (P = 0.001), overground walking speed (P = 0.029), and overground w alking endurance (P = 0.018). The follow-up evaluation, 3 months after training, revealed that the BWS group continues to have significantly higher scores for overground walking speed (P = 0.006) and motor recovery (P = 0.039). CONCLUSIONS Retraining gait in patients with stroke while a percentage of their body weight was supported resulted in better walking abilities than gait training while the patients were bearing their full weight. This novel gait training strategy provides a dynamic and integrative approach for the treatment of gait dysfunction after stroke.

Weight-supported treadmill vs over-ground training for walking after acute incomplete SCI

Objective: To compare the efficacy of step training with body weight support on a treadmill (BWSTT) with over-ground practice to the efficacy of a defined over-ground mobility therapy (CONT) in patients with incomplete spinal cord injury (SCI) admitted for inpatient rehabilitation. Methods: A total of 146 subjects from six regional centers within 8 weeks of SCI were entered in a single-blinded, multicenter, randomized clinical trial (MRCT). Subjects were graded on the American Spinal Injury Association Impairment Scale (ASIA) as B, C, or D with levels from C5 to L3 and had a Functional Independence Measure for locomotion (FIM-L) score <4. They received 12 weeks of equal time of BWSTT or CONT. Primary outcomes were FIM-L for ASIA B and C subjects and walking speed for ASIA C and D subjects 6 months after SCI. Results: No significant differences were found at entry between treatment groups or at 6 months for FIM-L (n = 108) or walking speed and distance (n = 72). In the upper motor neuron (UMN) subjects, 35% of ASIA B, 92% of ASIA C, and all ASIA D subjects walked independently. Velocities for UMN ASIA C and D subjects were not significantly different for BWSTT (1.1 ± 0.6 m/s, n = 30) and CONT (1.1 ± 0.7, n = 25) groups. Conclusions: The physical therapy strategies of body weight support on a treadmill and defined overground mobility therapy did not produce different outcomes. This finding was partly due to the unexpectedly high percentage of American Spinal Injury Association C subjects who achieved functional walking speeds, irrespective of treatment. The results provide new insight into disability after incomplete spinal cord injury and affirm the importance of the multicenter, randomized clinical trial to test rehabilitation strategies.

Optimal Outcomes Obtained With Body-Weight Support Combined With Treadmill Training in Stroke Subjects

OBJECTIVES To identify stroke patients who are most likely to benefit from locomotor training with body-weight support (BWS), to determine the extent of carryover from treadmill training to overground locomotion, and to determine the variables that are most likely to influence the recovery of locomotion. DESIGN A randomized clinical trial. SETTING Inpatient rehabilitation hospital. PARTICIPANTS Of 100 stroke subjects, 50 were randomized to receive locomotor training with BWS (BWS group), and 50 were randomized to receive locomotor training with full weight bearing (no-BWS group). The subjects were stratified according to their initial overground walking speed and endurance, initial treadmill speed and endurance, functional balance, motor recovery, side of the lesion, and age. INTERVENTION Fifty subjects were trained to walk on a treadmill with up to 40% of their body weight supported by a BWS system with an overhead harness (BWS group), and 50 subjects were trained to walk while bearing their full weight (no-BWS group). MAIN OUTCOME MEASURES Clinical outcome measures included overground walking speed and endurance, functional balance, and motor recovery. The effect of confounding variables such as age, comorbidity, and depression on locomotor outcome was also investigated. RESULTS After 6 weeks of locomotor training, the BWS group scored significantly higher in all clinical outcomes. When the subjects were stratified according to their initial overground walking speed, endurance, balance, and motor recovery, a significant statistical difference in gait and balance dysfunction of all outcomes occurred in the more severely impaired subjects. An important transfer from treadmill speed to overground walking speed was observed in subjects in the BWS group. Finally, a significantly greater effect was observed in older subjects (65-85y) in the BWS group. CONCLUSIONS Retraining gait in severely impaired stroke subjects with a percentage of their body weight supported resulted in better walking and postural abilities than did gait training in patients bearing their full weight. It appears that subjects with greater gait impairments benefited the most from training with BWS, as did the older patients with stroke. There is evidence of transfer from treadmill training to overground locomotion.

Intrinsic and reflex stiffness in normal and spastic, spinal cord injured subjects

Abstract. Mechanical changes underlying spastic hypertonia were explored using a parallel cascade system identification technique to evaluate the relative contributions of intrinsic and reflex mechanisms to dynamic ankle stiffness in healthy subjects (controls) and spastic, spinal cord injured (SCI) patients. We examined the modulation of the gain and dynamics of these components with ankle angle for both passive and active conditions. Four main findings emerged. First, intrinsic and reflex stiffness dynamics were qualitatively similar in SCI patients and controls. Intrinsic stiffness dynamics were well modeled by a linear second-order model relating intrinsic torque to joint position, while reflex stiffness dynamics were accurately described by a linear, third-order system relating half-wave rectified velocity to reflex torque. Differences between the two groups were evident in the values of four parameters, the elastic and viscous parameters for intrinsic stiffness and the gain and first-order cut-off frequency for reflex stiffness. Second, reflex stiffness was substantially increased in SCI patients, where it generated as much as 40% of the total torque variance, compared with controls, where reflex contributions never exceeded 7%. Third, differences between SCI patients and controls depended strongly on joint position, becoming larger as the ankle was dorsiflexed. At full plantarflexion, there was no difference between SCI and control subjects; in the mid-range, reflex stiffness was abnormally high in SCI patients; at full dorsiflexion, both reflex and intrinsic stiffness were larger than normal. Fourth, differences between SCI and control subjects were smaller during the active than the passive condition, because intrinsic stiffness increased more in controls than SCI subjects; nevertheless, reflex gain remained abnormally high in SCI patients. These results elucidate the nature and origins of the mechanical abnormalities associated with hypertonia and provide a better understanding of its functional and clinical implications.

Postural adaptation to walking on inclined surfaces: I. Normal strategies

This study investigated the postural strategies to adapt to uphill and downhill treadmill inclination (0, 5 and 10%) during walking and standing in eight healthy subjects. Increasing the treadmill grade from 0 to 10% induced an increasingly flexed posture of the hip, knee and ankle at initial foot contact as well as a progressive forward tilt of pelvis and trunk. These postural changes were accompanied by a progressive decrease in pelvic lateral drop toward the swinging limb and a gradual increase in stride length as the uphill slope became steeper. Decreasing the treadmill grade from 0 to -10% lead to a decreasingly flexed posture of the hip at initial foot contact as well as an increase in knee flexion during weight acceptance and late stance. These changes were accompanied by a gradual decrease in stride length, a progressive backward tilt of trunk and pelvis and an increase in pelvic lateral drop toward the swinging limb as downhill slope became steeper. Changes in trunk and pelvic postural alignment in the sagittal plane might be used to facilitate power generation or absorption in adapting to slope changes during walking. During quiet standing, however, the trunk and pelvis remained aligned with respect to earths vertical at any surface inclination. These results showed that postural adaptations are task-specific and the control requirements are different between standing and walking on an inclined surface.

Enhancement of locomotor recovery following spinal cord injury.

Recent advances have been made in new experimental approaches to enhance locomotor recovery in spinal cord-injured subjects. Research in adult animals whose spinal cords have been transected (spinal animals) has focused particularly on locomotor recovery and the use of pharmacological tools to trigger and modulate the locomotor pattern. This provides a rational basis for the rehabilitation and pharmacotherapy of locomotion in spinal cord-injured patients. Findings in the field of locomotor training, locomotor pharmacotherapy, and functional electrical stimulation are reviewed. It is argued that a combination of the various approaches will provide an optimal base for functional locomotor recovery.

The evolution of walking-related outcomes over the first 12 weeks of rehabilitation for incomplete traumatic spinal cord injury: the multicenter randomized Spinal Cord Injury Locomotor Trial.

Background. The Spinal Cord Injury Locomotor Trial (SCILT) compared 12 weeks of step training with body weight support on a treadmill (BWSTT) that included overground practice to a defined but more conventional overground mobility intervention (CONT) in patients with incomplete traumatic SCI within 8 weeks of onset. No previous studies have reported walking-related outcomes during rehabilitation. Methods. This single-blinded, randomized trial entered 107 American Spinal Injury Association (ASIA) C and D patients and 38 ASIA B patients with lesions between C5 and L3 who were unable to walk on admission for rehabilitation. The Functional Independence Measure (FIM-L) for walking, 15-m walking speed, and lower extremity motor score (LEMS) were collected every 2 weeks. Results. No significant differences were found at entry and during the treatment phase (12-week mean FIM-L = 5, velocity = 0.8 m/s, LEMS = 35, distance walked in 6 min = 250 m). Combining the 2 arms, a FIM-L ≥ 4 was achieved in < 10% of ASIA B patients, 92% of ASIA C patients, and all of ASIA D patients. Walking speed of ≥ 0.6 m/s correlated with a LEMS near 40 or higher. Conclusions. Few ASIA B and most ASIA C and D patients achieved functional walking ability by the end of 12 weeks of BWSTT and CONT, consistent with the primary outcome data at 6 months. Walking-related measures assessed at 2-week intervals reveal that time after SCI is an important variable for entering patients into a trial with mobility outcomes. By about 6 weeks after entry, most patients who will recover have improved their FIM-L to >3 and are improving in walking speed. Future trials may reduce the number needed to treat by entering patients with FIM-L < 4 at > 8 weeks after onset if still graded ASIA B and at > 12 weeks if still ASIA C.

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

OBJECTIVE To present some recent developments and concepts emerging from both animal and human studies aimed at enhancing recovery of walking after spinal cord injury (SCI). DATA SOURCES Researchers in the field of restoration of walking after SCI, as well as references extracted from searches in the Medline computerized database. STUDY SELECTION Studies that reported outcome measures of walking for spinal cord injured persons with an incomplete motor function loss or cats with either a complete or incomplete spinal section. DATA EXTRACTION Data were extracted and validity was assessed by the authors. DATA SYNTHESIS This review shows that a multitude of interventions--mechanical, electrical, or pharmacologic--can increase the walking abilities of persons with SCI who have incomplete motor function loss. CONCLUSIONS A comprehensive evaluation of walking behavior requires tasks involving the different control variables. This comprehensive evaluation can be used to characterize the process of recovery of walking as well as the effectiveness of various treatments.

Methods for a Randomized Trial of Weight-Supported Treadmill Training Versus Conventional Training for Walking During Inpatient Rehabilitation after Incomplete Traumatic Spinal Cord Injury

The authors describe the rationale and methodology for the first prospective, multicenter, randomized clinical trial (RCT) of a task-oriented walking intervention for subjects during early rehabilitation for an acute traumatic spinal cord injury (SCI). The experimental strategy, body weight-supported treadmill training (BWSTT), allows physical therapists to systematically train patients to walk on a treadmill at increasing speeds typical of community ambulation with increasing weight bearing. The therapists provide verbal and tactile cues to facilitate the kinematic, kinetic, and temporal features of walking. Subjects were randomly assigned to a conventional therapy program for mobility versus the same intensity and duration of a combination of BWSTT and over-ground locomotor retraining. Subjects had an incomplete SCI (American Spinal Injury Association grades B, C, and D) from C-4 to T-10 (upper motoneuron group) or from T-11 to L-3 (lower motoneuron group). Within 8 weeks of a SCI, 146 subjects were entered for 12 weeks of intervention. The 2 single-blinded primary outcome measures are the level of independence for ambulation and, for those who are able to walk, the maximal speed for walking 50 feet, tested 6 and 12 months after randomization. The trials methodology offers a model for the feasibility of translating neuroscientific experiments into a RCT to develop evidence-based rehabilitation practices.

Locomotor training in neurorehabilitation: emerging rehabilitation concepts.

Since the publication of the review of treadmill training in Neurorehabilitation & Neural Repair published in 1999, several new clinical studies have been presented on locomotor training as a rehabilitation approach for stroke and spinal cord injured subjects. In the series of expert commentaries,1 different authors expressed a spectrum of views on this new rehabilitation strategy (see also Dobkin2). The potentials and limitations on such approaches of the recovery of stroke, spinal cord–injured subjects, and other neurological populations were discussed. The goal of this article is to present the newest evidence that locomotor training is one of the evidence-based clinical approaches that will be used in the 21st century to enhance recovery of posture and locomotion in stroke, spinal cord injury subjects and in many other neurological conditions. The training strategies include modern approaches of motor learning such as task specificity training of walking and balance in both feed-forward and feedback modes. Figure 1 (left side) illustrates a comprehensive schematic of several important factors necessary to achieve functional recovery. Several new approaches from animal studies, predevelopment studies, and phase I to phase III clinical trials have been developed in the last 2 decades, such as locomotor training on treadmill and on the ground using body weight support (BWS), functional electrical stimulation (FES), and pharmacological approaches and their combination to enhanced recovery in the neurological population particularly stroke and spinal cord injury (SCI) subjects. These individual approaches have shown great potential and are different in the process of validation in the rehabilitation setting. Recent reviews summarize those findings.3-6 Stroke and SCI subjects can adapt, to a certain limit, the functional prerequisite of posture and walking, such as speed, slope, obstacles, including stairs, walking aids, energy consumption, and attentional and navigational demands (Figure 1, right column).7 Understanding the strategy that SCI and stroke subjects use can contribute to the development of concepts and principles that can be included in rehabilitation. Figure 1 also illustrates how treatment approaches affect such prerequisites7 necessary to achieve functional recovery. From Figure 1 (lower panel), several important concepts for rehabilitation have emerged and will be presented in the following section.