The Walking Index for Spinal Cord Injury (WISCI/WISCI II): nature, metric properties, use and misuse.

STUDY DESIGN: Literature review. OBJECTIVE: To critically review all publications/internet sites that have described/used the Walking Index for Spinal Cord Injury (WISCI II), as a measure of impairment of walking function after spinal cord injury (SCI), in order to identify its psychometric properties, clarify its nature, specify misuse and incorporate the findings in an updated guide. METHOD: A systematic literature search was done of Ovid MEDLINE, CINAHL, PsychINFO, Cochrane Central Register of Controlled Trials, Scopus and electronic sites using key words: WISCI or WISCI II, SCI, paraplegia/ tetraplegia/ quadriplegia and ambulation/gait/walking. Among 1235 citations retrieved, 154 relevant articles/sites were identified, classified and examined by the authors; recommendations were made based on findings. RESULTS AND DISCUSSION: The validity (face/concurrent/content/construct/convergent/criterion) and reliability of the WISCI II has been documented in clinical trials and clinical series, and considered adequate by systematic reviewers. In chronic SCI subjects, reliable determination of the maximum (as opposed to self-selected) WISCI II level requires more time and experience by the assessor. The correct use of WISCI II is clarified for testing acute/chronic phases of recovery after SCI, age of subjects, devices and settings. The WISCI II and walking speed measures may be performed simultaneously. CONCLUSION: The increased use of the WISCI II is attributed to its unique characteristics as a capacity measure of walking function and its strong metric properties. Appropriate use of the WISCI II was clarified and incorporated into a new guide for its use. Combining it with a walking speed measure needs further study.

Comparison of speeds used for the 15.2-meter and 6-minute walks over the year after an incomplete spinal cord injury: the SCILT Trial.

BACKGROUND: Timed walking speed for 6 to 15 m and the distance walked in 2 to 12 minutes are frequently used outcome measures in rehabilitation trials, presumably reflecting different aspects of walking ability. The database from the Spinal Cord Injury Locomotor Trial (SCILT), which tested 2 interventions for mobility upon admission for initial rehabilitation of an incomplete traumatic spinal cord injury (SCI), was used to compare the walking speed employed for each test. METHODS: From 66 to 70 patients with upper motor neuron lesions from C-5 to T-10 performed a 15.2-m and a 6-minute walk as fast as the patient deemed safe at 3 months (end of the trial intervention) and 6 and 12 months after entry. The means, standard errors, and quartiles were calculated for the speed used for each task. RESULTS: The mean speed for the 15.2-m walk did not differ from that used for the 6-minute walk at 3 and 6 months but was significantly faster at 12 months. Differences became apparent at each assessment in patients in the highest quartiles (>1.0 m/s) for the 15.2-m walk. Their speed was from 14% to 24% higher than the speed used for the 6-minute walk. CONCLUSION: The speed of the 15.2-m walk as a measure of walking ability compared to the distance walked in 6 minutes may not represent separable domains of mobility. Differences were apparent only in the most highly functional patients, who could ambulate in the community. Any difference in the walking speed used for these 2 tasks does not make enough of a clinical distinction to encourage including both a 6-minute walk and a 15.2-m walk as outcome measures in clinical trials of locomotor interventions for SCI.

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 >or= 4 was achieved in < 10% of ASIA B patients, 92% of ASIA C patients, and all of ASIA D patients. Walking speed of >or= 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.

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.

Effect of 4-aminopyridine on gait in ambulatory spinal cord injuries: a double-blind, placebo-controlled, crossover trial.

UNLABELLED: Animal and human research have shown that the drug 4-aminopyridine (4-AP) may improve gait in spinal cord lesions by enhancing nerve transmission to affected muscles. STUDY DESIGN: Prospective, randomized, double-blind, placebo-controlled, crossover trial. OBJECTIVES: To determine the efficacy of 4-AP in improving lower limb muscle strength and biomechanical gait patterns of chronic spinal cord injuries (SCI). SETTING: The Rehabilitation Centre (Ottawa, Canada). METHODS: In all, 15 chronic, ambulatory SCI persons were randomized to an initial 2 weeks of 40 mg/day, oral medication of either placebo or immediate-release, 4-AP and subsequently crossed over to the alternate medication for the following 2 weeks. Evaluations were conducted at baseline (before starting 4-AP or placebo medication), 2 weeks, and 4 weeks. Measures included dynamometer lower limb isometric muscle force and biomechanical gait measures including temporal-spatial parameters, electromyographic activation patterns, joint kinematics and kinetics. Subjective impressions of the drug by the participants were obtained from an exit survey. RESULTS: Despite some positive comments from subjects, statistical and clinical analyses showed no within-subject differences between placebo and 4-AP measures of lower limb muscle force and objective gait analyses (ANOVA statistic P>0.05). CONCLUSION: Results demonstrated the importance of placebo-controlled trials and quantitative outcome measures for the evaluation of 4-AP aimed to enhance gait for chronic, ambulatory SCI persons. Energy expenditure measures and mood may relate more to subjective comments and is suggested for future investigations.

Treadmill walking in incomplete spinal-cord-injured subjects: 1. Adaptation to changes in speed.

UNLABELLED: Walking in spinal-cord-injured (SCI) subjects is usually achieved at a lower speed than in normal subjects. STUDY DESIGN/METHODS: Time and distance parameters, angular displacements of lower limbs and electromyographic (EMG) activity were measured for seven normal and seven SCI subjects at several walking speeds. Analyses of variance were used for comparing groups and speeds. OBJECTIVES: First, to measure the adaptability of SCI subjects' walking pattern to different speeds (0.1-1.0 m/s), and to compare it to that of normal subjects. Second, to characterize SCI subjects' walking pattern as compared to that of normal subjects at a matched treadmill speed (0.3 m/s). SETTING: University-Based Human Gait Laboratory, Montreal, Canada. RESULTS: SCI subjects' pattern adapted to a limited range of speeds. Longer cycle duration, flexed knee at foot contact, increased hip joint flexion at foot contact and during swing, and altered coordination of hip and knee joints were found for the SCI group. At all speeds, duration of muscle activity was longer in the SCI group and the increase in amplitude of soleus EMG activity at higher speeds was not specific to push-off. The importance of matching the walking speed of SCI and normal subjects in order to differentiate the features that are a consequence of SCI subjects' reduced walking speed rather than a direct consequence of the injury is demonstrated. CONCLUSIONS: All SCI subjects could adapt to a narrow range of speeds and only three could reach the maximal tested speed. This limited maximal speed seems to be a consequence of SCI subjects having reached their limit in increasing stride length and not being able to increase stride frequency further. This limitation in increasing stride frequency is likely because of the altered neural drive. SPONSORSHIP: Neuroscience Network of the Canadian Centre of Excellence.

Treadmill walking in incomplete spinal-cord-injured subjects: 2. Factors limiting the maximal speed.

STUDY DESIGN/METHODS: Five SCI subjects referred to the laboratory and a convenience sample of five normal volunteer individuals was selected. Stride length and frequency were measured at different walking speeds under three different conditions: preferred, highest possible and lowest possible stepping frequencies. OBJECTIVE: To determine which factors are limiting the maximal walking speed in spinal-cord-injured (SCI) individuals. SETTING: University-Based Human Gait Laboratory, Montreal, Canada. RESULTS: It is shown that maximal stride frequency was the predominant limiting factor of the maximal treadmill-walking speed in SCI subjects. These results were explained in the light of the forced hybrid mass-spring pendulum model. At all speeds, SCI subjects spent longer time in stance, swing and double support phases. The relative time spent in single support is greater at higher walking speed and the difficulty to reduce double support time is a limiting factor. CONCLUSIONS: A better understanding of the factors limiting the maximal speed in SCI subjects should help developing rehabilitation interventions oriented towards increasing the control and the capacity of walking. Rehabilitation strategies should put the emphasis on improving the capacity to produce rapid alternate rhythmical stepping movements of the lower limbs. SPONSORSHIP: Neuroscience Network of the Canadian Centre of Excellence.

The effect of noradrenergic drugs on the recovery of walking after spinal cord injury.

UNLABELLED: Clonidine, a noradrenergic agonist has been associated with improved walking in both spinal cat and spinal cord injured (SCI) subjects. OBJECTIVES: The objective of this brief review is to compare the effects of clonidine on walking capabilities in SCI subjects with functionally complete and incomplete spinal cord injuries. STUDY DESIGN/METHODS: Both oral administration and intrathecal injection of clonidine were investigated. A motorized treadmill was used and harness support provided in most of the SCI subjects as no walking capabilities could be observed overground. A single subject design was used in these chronic SCI subjects. SETTING: Canada and France. RESULTS: In complete SCI subjects while receiving clonidine, none of the subjects was able to initiate independent stepping. In contrast, the greatest effects were found in SCI subjects with injuries that are incomplete but still severely disabling while minimal effects could be observed in the more functional SCI subjects. These effects on walking are observed in measures of walking speed, and electromyographic and kinematic patterns. Regardless of effects on walking, however, a consistent decrease of the flexor reflex amplitude could be observed in all SCI subjects independent of the severity of the lesion. CONCLUSION: This review demonstrated that clonidine could be a powerful anti-spasmodic drug in addition to improving locomotion in a limited number of SCI subjects. The mechanism, significance and implications of these results will be discussed.

Effect of intrathecal clonidine on group I and group II oligosynaptic excitation in paraplegics.

We investigated the possibility that a change in transmission in group II pathways contributes to the spasticity of patients with spinal lesions. Thirteen patients were tested by measuring the quadriceps stretch reflex (Ashworth scale), the threshold of the quadriceps H reflex, and the oligosynaptic facilitation of the quadriceps H reflex elicited by volleys to groups I and II afferents in the common peroneal nerve (CPN). All these tests were performed before and after intrathecal injection of clonidine (60 microg). Early group I CPN-induced excitations occurred in 13 patients, and late group II CPN-induced excitations in 12. Both facilitations were, on average, significantly greater than those reported for normal subjects, but these increases were not correlated with the clinically assessed spasticity. Clonidine caused a constant, prolonged and dramatic decrease in spasticity, but did not alter the threshold of the quadriceps H reflex. CPN-induced group I and group II non-monosynaptic excitations of quadriceps motoneurones were significantly decreased, although they did not return to normal values. These results provide a further indication that group II pathways gives rise to the heteronymous late CPN-induced excitation. The pathophysiological role of a change in transmission in group II pathways in spasticity is discussed.

A review of the adaptability and recovery of locomotion after spinal cord injury.

Spinal cord injury (SCI) is associated with multiple motor problems leading to the alteration and limited adaptation in the walking and postural behavior. This review addresses recent findings on locomotor and postural adaptations after spinal cord injury. The adaptation of the locomotor behavior to behavioral goals and external constraints constitute important functional prerequisites in the recovery of locomotion after spinal cord injury. Functional prerequisites in locomotion include coping with changes in speed, slope obstacle, weight support, interaction with walking aids, energy consumption and attentional demands. Various treatment approaches such as locomotor training using body weight support (BWS) and functional electrical stimulation (FES) will be discussed, in the context of functional prerequisites necessary in the recovery of locomotion. Understanding locomotor and postural adaptations will lead to a better appreciation of the normal and dysfunctional mechanisms, and culminate eventually in the development of appropriate rehabilitation assessment and treatment strategies.

The role of rehabilitation in the recovery of walking in the neurological population.

Recent studies demonstrate that neurological patients show great potential for recovery in both the early and late stages following injury. Enhancement of the recovery process could be achieved with new rehabilitation approaches alone or in combination with pharmacological intervention. These new approaches have evolved from fundamental advances in both animal and human studies. To date few randomized clinical trials have addressed the efficacy or effectiveness of these new approaches. In this paper, important quantitative studies will be reviewed and discussed in relation to the important mechanisms of locomotor control and plasticity that take place following lesions of the central nervous system.

Functional community ambulation requirements in incomplete spinal cord injured subjects.

STUDY DESIGN: A group of people with incomplete spinal cord injuries (SCI) were evaluated and compared with able-bodied individuals during several walking conditions. OBJECTIVES: To evaluate the functional community ambulation and estimated energy expenditure in persons with incomplete SCI and able-bodied individuals. METHODS: A list of criteria was used to evaluate functional community ambulation among participants. Physiological variables, such as the heart rate, oxygen uptake and the lactate concentration, were also measured. RESULTS: Three of nine incomplete SCI subjects and all able-bodied subjects were able to meet all the criteria measured. The required velocity to safely cross an intersection was the criterion that the incomplete SCI group had the most difficulty reaching. The able-bodied subjects had a comfortable walking velocity twice that of the incomplete SCI subjects' preferred velocity. When walking at the same velocity (incomplete SCI subjects' preferred velocity), the incomplete SCI subjects had a rate of oxygen uptake 26% greater than the healthy subjects and were 200% less efficient. The lactate concentration also proved to be a useful tool when evaluating the incomplete SCI subjects' walking efficiency. The incomplete SCI subjects lactate concentration increased after walking at their preferred velocity, meaning that the anaerobic pathways were used to meet energy demands. CONCLUSION: Rehabilitation centers should adapt their evaluation forms and increase their criteria requirements to more suitable criteria that are found in the SCI patient's community. The physiological cost should also be taken into consideration when evaluating the SCI patient's functional ambulation.

Body weight-supported treadmill training after stroke.

Gait rehabilitation is a major aspect of neurologic rehabilitation. This review focuses on locomotor therapy by treadmill stimulation with partial body weight support (BWS), which has become a very promising treatment concept over the past few years. It enables severely affected patients to follow modern aspects of motor learning, favoring a task-specific approach. Initially two therapists assist the movement, placing the paretic limbs and controlling the trunk movements. As compared with overground walking, patients walked more symmetrically, less spastically, and more efficiently on the treadmill with BWS. Several clinical controlled studies have shown its potential in patients after stroke, who regained walking ability faster in the acute or in the chronic stage. Controlled multicenter trials comparing locomotor and conventional therapy will be the next step. Also, the use of BWS during overground walking could be incorporated into the locomotor treatment program of less affected stroke patients. An electromechanical gait trainer relieving the strenuous effort of the therapists and controlling the trunk in a phase-dependent manner is a new technical alternative for severe stroke patients.

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

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.

Functional electrical stimulation-assisted walking for persons with incomplete spinal injuries: changes in the kinematics and physiological cost of overground walking.

This study was conducted to investigate the change in the kinematics and physiological cost of walking that occurs during training with functional electrical stimulation (FES)-assisted walking in persons with incomplete injuries. The main effect of FES-assisted walking was to change hip excursion and ankle dorsiflexion during swing and at foot contact, whereas training with FES-assisted walking changed the spatio-temporal parameters of walking (walking speed, cycle length and frequency as well as time in stance). The use of FES-assisted walking does not change the walking speed achieved during a 5-minute trial nor the physiological cost of walking but when combined with walking training, eight of the nine participants improved either their physiological cost index or their walking speed. It is concluded that FES-assisted walking changes the joint angular kinematic pattern of walking, but training is necessary to integrate these changes into functional gains.

Walking index for spinal cord injury (WISCI): an international multicenter validity and reliability study.

STUDY DESIGN: Construction of an international walking scale by a modified Delphi technique. OBJECTIVE: The purpose of the study was to develop a more precise walking scale for use in clinical trials of subjects with spinal cord injury (SCI) and to determine its validity and reliability. SETTING: Eight SCI centers in Australia, Brazil, Canada (2), Korea, Italy, the UK and the US. METHODS: Original items were constructed by experts at two SCI centers (Italy and the US) and blindly ranked in an hierarchical order (pilot data). These items were compared to the Functional Independence Measure (FIM) for concurrent validity. Subsequent independent blind rank ordering of items was completed at all eight centers (24 individuals and eight teams). Final consensus on rank ordering was reached during an international meeting (face validation). A videotape comprised of 40 clips of patients walking was forwarded to all eight centers and inter-rater reliability data collected. RESULTS: Kendall coefficient of concordance for the pilot data was significant (W=0. 843, P<0.001) indicating agreement among the experts in rank ordering of original items. FIM comparison (Spearman's rank correlation coefficient=0.765, P<0.001) showed a theoretical relationship, however a practical difference in what is measured by each scale. Kendall coefficient of concordance for the international blind hierarchical ranking showed significance (W=0.860, P<0.001) indicating agreement in rank ordering across all eight centers. Group consensus meeting resulted in a 19 item hierarchical rank ordered 'Walking Index for Spinal Cord Injury (WISCI)'. Inter-rater reliability scoring of the 40 video clips showed 100% agreement. CONCLUSIONS: This is the first time a walking scale for SCI of this complexity has been developed and judged by an international group of experts. The WISCI showed good validity and reliability, but needs to be assessed in clinical settings for responsiveness.

Functional electrical stimulation-assisted walking for persons with incomplete spinal injuries: longitudinal changes in maximal overground walking speed.

This study investigated the changes in maximal overground walking speed (MOWS) that occurred during walking training with a functional electrical stimulation (FES) orthosis by chronic spinal cord injured persons with incomplete motor function loss. The average walking speed over a distance of 10 m was calculated while the participants (n = 14) used their FES orthosis with and without power as well as with the various ambulatory assistive devices available. Within the first year of use, walking with an FES orthosis facilitated use of more advanced ambulatory assistive devices (10/14), improvements in functional mobility (12/14) and increases in the combined (0.26 m/s) and therapeutic (0.25 m/s) MOWS that were correlated (combined: r = 0.57; therapeutic: r = 0.69) with their respective initial MOWS. A longitudinal analysis showed that increases in MOWS followed a pattern of changes best described by either an exponential association (8/12) or a linear (4/12) model. These changes were similar for the combined and therapeutic MOWS (7/11) as well as for the different ambulatory assistive devices (8/9). It is concluded that the increased MOWS during walking training using the FES orthosis is mostly due to a therapeutic effect, implying that mechanisms of plasticity occur during such a training paradigm.

Posture-related changes in heteronymous recurrent inhibition from quadriceps to ankle muscles in humans.

The possibility was investigated that changes in heteronymous recurrent inhibition (RI) from quadriceps (Q) to soleus (Sol) and tibialis anterior (TA) motoneurons (MNs) occur during postural tasks requiring cocontraction of Q with one of these muscles. Stimulation of the femoral nerve (FN), which elicited a Q H-reflex discharge, was used to activate Renshaw cells. The resulting inhibition of TA and Sol MNs was assessed using three test responses: (1) the rectified and averaged ongoing electromyogram (EMG) activity in TA or Sol; (2) the motor-evoked potential (MEP) elicited by cortical stimulation in these muscles; and (3) the Sol H reflex. The characteristics of the depression (appearance and increase with the conditioning reflex discharge, short central delay and long duration) are consistent with a Renshaw origin. In addition, results obtained in control experiments (no change in the EMG suppression after an ischaemic blockade of group-I afferents from the leg, time course of the FN-induced depression of the MEP similar to that of the ongoing EMG) made a significant contribution from other pathways activated by FN stimulation unlikely. Posture-related heteronymous RI from Q was compared in different postural tasks at matched levels of background EMG activity: voluntary co-contraction of Q and of the relevant ankle muscle while sitting (control situation), postural co-contraction of Q and TA (while leaning backwards during stance), or contraction of Sol with (preparation for hopping) and without (standing on tip of toes and leaning forwards during stance) associated contraction of the Q. During stance, heteronymous RI from Q was reduced to TA (but not to Sol) while leaning backwards and to Sol in preparation for hopping, but not in the other situations. Thus, RI from Q to TA or Sol was specifically decreased when a co-contraction of the Q and of the relevant muscle operating at the ankle was required to maintain bipedal stance. It is argued that this control of Renshaw cells is descending in origin and contributes to selection of the appropriate synergism in various postural tasks.