Markus Wirz

Driven gait orthosis for improvement of locomotor training in paraplegic patients

Design: Single cases.Objective: To compare the effects of manually assisted locomotor training in paraplegic patients with the automated training by a driven gait orthosis.Setting: ParaCare, University Hospital Balgrist in Zurich, Switzerland.Methods: Treadmill training with manual assistance and by a driven gait orthosis was applied to two spinal cord injured patients. The first patient had an incomplete lesion at C3, the second a complete lesion at C5. They were selected by convenience sample. The EMG activity of the leg muscles rectus femoris, biceps femoris, gastrocnemius medials (GM) and tibialis anterior (TA) was visually compared for the two training methods. GM and TA activity was also quantified by calculating the variation ratio between the EMG of the patients and a set of healthy subjects.Results: No significant difference between the two training methods was found according to the leg muscle EMG activity.Conclusion: Neuronal centers in the spinal cord become activated in a similar way by the manually assisted and the automated locomotor training. With the driven gait orthosis training sessions can be prolonged and workload of therapists can be reduced, and therefore, the automated training represents an alternative to the conventional therapy.Spinal Cord (2001) 39, 252–255.

Locomotor pattern in paraplegic patients: training effects and recovery of spinal cord function

Recent studies have shown that a locomotor pattern can be induced and utilized by paraplegic patients under conditions of body unloading using a moving treadmill. The present study investigated the behaviour of the locomotor pattern and also the relationship of its development to the spontaneous recovery of spinal cord function assessed by clinical and electrophysiological (tibial nerve somatosensory evoked potentials and motor evoked potentials) examinations. The earliest time that spinal locomotor activity could be induced was when signs of spinal shock had disappeared. This activity was distinct from spinal stretch reflex activity. In complete paraplegic patients the locomotor pattern improved spontaneously without training. This was coincident with both an increase of gastrocnemius electromyographic activity during the stance phase of gait and a decrease of body unloading. These effects reached a plateau after about 5 weeks. In complete and incomplete paraplegic patients a near linear increase of gastrocnemius electromyographic activity occurred during the stance phase of a step cycle with daily locomotor training over the whole training period of 12 weeks. This was also coincident with a significant decrease of body unloading. In contrast to this, neither clinical nor electrophysiological examination scores improved after the onset of training in both patient groups. Only in incomplete paraplegic patients was there recovery, albeit statistically insignificant, of spinal cord function according to the sensory and motor scores obtained in the neurological examination during the time period before onset of training. An improvement of locomotor function by training was also seen in patients with paraplegia due to a cauda lesion. Such training effects on muscles and tendons could be separated from those on the spinal locomotor centres. The findings of this study may be relevant for the future clinical treatment of paraplegic patients.

Long term effects of locomotor training in spinal humans

The long term effects of locomotor training in patients with spinal cord injury (SCI) were studied. In patients with complete or incomplete SCI coordinated stepping movements were induced and trained by bodyweight support and standing on a moving treadmill. The leg extensor muscle EMG activity in both groups of patients increased significantly over the training period, associated with improved locomotor ability in those with incomplete SCI. During a period of more than 3 years after training, the level of leg extensor EMG remained about constant in incomplete SCI in those who regularly maintained locomotor activity. By contrast the EMG significantly fell in those with complete SCI. The results suggest a training induced plasticity of neuronal centres in the isolated spinal cord which may be of relevance for future interventional therapies.

Improving walking assessment in subjects with an incomplete spinal cord injury : responsiveness

Study design:Prospective longitudinal study.Objectives:To investigate the responsiveness of the Walking Index for Spinal Cord Injury II (WISCI II), 6-Min Walk (6MWT) and 10-Meter Walk Tests (10MWT) for the assessment of walking capacity in incomplete spinal cord injury (iSCI) and to validate these tests with the lower extremity motor score (LEMS).Setting:European Multicenter Study of Human Spinal Cord Injury.Methods:The walking tests of 22 iSCI subjects who achieved functional ambulation and could stand or walk within 1 month after iSCI were analyzed at 3, 6 and 12 months after injury. Responsiveness was assessed by determining differences between the time intervals, and Spearmans correlation coefficient was calculated to quantify validity.Results:All walking tests were able to assess the improvement of walking capacity within the first 3 months after injury. Between 3 and 6 months, only the 10MWT and 6MWT were responsive to the ongoing improvement in locomotor capacity. Overall, correlations between the tests were good within the first month, but became poorer over time.Conclusion:The 6MWT and 10MWT were more responsive in demonstrating an improvement in walking capacity compared to the WISCI II. The testing of functional outcome after iSCI as provided by the ordinal ASIA motor score can be improved by interval scaled measures. This allows increasing the responsiveness of functional outcome measures and should be advantageous in assessing therapeutical approaches in iSCI subjects. In iSCI subjects with walking ability, we recommend the additional use of timed tests to monitor improvement in locomotor capacity.

Falls in Persons With Spinal Cord Injury: Validity and Reliability of the Berg Balance Scale

Background. Persons with spinal cord injury who are able to walk are at risk for falls. Objective . The objectives were to investigate if the Berg Balance Scale (BBS) can discriminate those with a propensity to fall; to determine whether the BBS is associated with mobility measures, fear of falling, and muscle strength; and to assess interobserver reliability. Methods. The measurement tools used were the BBS, the Spinal Cord Independence Measure, the Falls Efficacy Scale (FES-I), the Walking Index for Spinal Cord Injury, the 10-m walk test, and the standard neurological classification including motor scores (MS). Falls were recorded retrospectively for the previous month and prospectively for the subsequent 4 months. To determine interobserver reliability, BBS performance was videotaped and analyzed by additional physical therapists. Associations between BBS and the number of falls, measures of mobility, FES-I, and MS were calculated using Spearman correlations. The interobserver reliability was quantified using Kendall’s coefficient of concordance and intraclass correlation coefficients (ICCs). Results. Forty-two participants were included of whom 26 sustained 1 or more falls. BBS performance correlated with measures of mobility, FES-I, and MS (rs = -.83 to .93; P < .001) but not with the number of falls (rs = -.17; P = .28). The interobserver reliability was excellent, both for single items (.84-.98, P < .001) and for the total score (ICC = .95; 95% confidence interval = 0.910-0.975). Conclusions. The BBS proved to be reliable and to relate well with other mobility measures, fear of falling, and muscle strength. However, it was unable discriminate between people who did fall and people who did not fall.

Locomotor capacity and recovery of spinal cord function in paraplegic patients: a clinical and electrophysiological evaluation

Recent studies have shown that a locomotor pattern can be induced and trained into paraplegic patients under conditions of body unloading using a moving treadmill. The present study investigated the behaviour of the locomotor pattern and also the relationship of its development to the spontaneous recovery of spinal cord function assessed by clinical and electrophysiological (tibial nerve somatosensory evoked potentials and motor evoked potentials) examinations. The earliest time that spinal locomotor activity could be induced was when signs of spinal shock had disappeared. This activity was distinct from spinal stretch reflex activity. In complete and incomplete paraplegic patients an increase of gastrocnemius electromyographic activity occurred during the stance phase of a step cycle with daily locomotor training over the whole training period of 12 weeks. This was coincident with a significant decrease in body unloading. In contrast to this, neither clinical nor electrophysiological examination scores improved after the onset of training in both patient groups. Only in incomplete paraplegic patients was there an insignificant increase in sensory and motor scores obtained in the neurological examination during the time period before onset of training. An improvement of locomotor function by training was also seen in patients with paraplegia due to a cauda lesion. Therefore, in patients with a spinal cord lesion training effects on muscles and tendons are present in addition to those on the spinal locomotor centres. The findings of this study may be relevant for future clinical treatment of paraplegic patients.

Standardized assessment of walking capacity after spinal cord injury: the European network approach.

Abstract Objectives: After a spinal cord injury (SCI), walking function is an important outcome measure for rehabilitation and new treatment interventions. The current status of four walking capacity tests that are applied to SCI subjects is presented: the revised walking index for spinal cord injury (WISCI II), the 6 minute walk test (6MinWT), 10 meter walk test (10MWT) and the timed up and go (TUG) test. Then, we investigated which categories of the WISCI II apply to SCI subjects who participated in the European Multicenter Study of Human Spinal Cord Injury (EM-SCI), and the relationship between the 10MWT and the TUG. Methods: In the EM-SCI, the walking tests were applied 2 weeks and 1, 3, 6 and 12 months after SCI. We identified the WISCI II categories that applied to the EM-SCI subjects at each time point and quantified the relationship between the 10MWT and the TUG using Spearmans correlation coefficients (ρ) and linear regression. Results: Five WISCI II categories applied to 71% of the EM-SCI subjects with walking ability, while 11 items applied to 11% of the subjects. The 10MWT correlated excellently with the TUG at each time point (ρ>0.80). However, this relationship changed over time. One year after SCI, the time needed to accomplish the TUG was 1.25 times greater than the 10MWT time. Discussion: Some categories of the WISCI II appear to be redundant, while some discriminate to an insufficient degree. In addition, there appear to be ceiling effects, which limit its usefulness. The relationship between the 10MWT and TUG is high, but changes over time. We suggest that, at present, the 10MWT appears to be the best tool to assess walking capacity in SCI subjects. Additional valuable information is provided by assessing the needs for walking aids or personal assistance. To ensure comparability of study results, proposals for standardized instructions are presented.

Swing phase resistance enhances flexor muscle activity during treadmill locomotion in incomplete spinal cord injury.

Background. This study investigated whether loading the legs during the swing phase of walking enhances flexor muscle activity in ambulatory patients with incomplete spinal cord injury (SCI). Methods. Nine patients had surface electromyography (EMG) and joint kinematics recorded from the lower extremities during treadmill walking. Swing phase loading of the legs was achieved by weights (1-3 kg) attached to each lower extremity or by a velocity-dependent resistance applied by the Lokomat robotic gait orthosis. Results. When patients walked with the weights, there was a consistent increase in the activity of the knee flexors and sometimes of hip or ankle flexor activity during swing. Similarly, when the robot applied the velocity-dependent resistance during walking, swing phase flexor EMG activity tended to be greater. Enhanced knee flexion was observed in all patients after the weights or the robot-generated resistance was removed. Conclusions. Flexor muscle activity during swing can be enhanced through additional proprioceptive input in patients with incomplete SCI with brief aftereffects. Further testing of this strategy is necessary to determine if it can improve the gait of ambulatory patients.

Level of spinal cord lesion determines locomotor activity in spinal man.

Abstract Recent studies have demonstrated that coordinated stepping movements can be induced in patients with complete para-/tetraplegia, when they were standing on a moving treadmill with their body weight partially unloaded and external assistance. The aim of this study was to determine which part of the spinal cord generated the locomotor pattern. In patients with complete paraplegia due to lesions at different levels of the spinal cord, the locomotor pattern was compared with that of healthy subjects. Any similarities in electromyographic (EMG) activity of gastrocnemius and tibialis anterior muscles between the patients and healthy subjects were reflected by the analysis of the variation ratio and amplitudes of the EMG activity. It was found that the higher the level of spinal cord lesion the more ”normal” was the locomotor pattern. This suggests that neuronal circuits underlying locomotor ”pattern generation” in man are not restricted to any specific level(s) of the spinal cord, but that an intricate neuronal network contributing to bipedal locomotion extends from thoracolumbal to cervical levels.

Difficulty of Elderly SCI Subjects to Translate Motor Recovery—“Body Function”—into Daily Living Activities

The objective of this retrospective analysis was to determine whether outcome of body functions and activities as well as length of stay of inpatient rehabilitation is related to age in patients with traumatic spinal cord injury (SCI). Data were collected from a European network of 17 SCI rehabilitation centers (EM-SCI); a total of 237 traumatic SCI subjects were included. Assessments were performed at 1, 6, and 12 months after SCI. The measures analyzed were motor score according to the American Spinal Injury Association, Spinal Cord Independence Measure (SCIM), gait speed, and length of stay. Correlation analysis was applied to quantify the association between age and change in the outcome measures. A positive relationship was found between age and neurological recovery in both the first and second 6-month periods of assessment. A negative relationship was found between age and change in SCIM in the second 6-month period after SCI. A negative relationship between age and gait speed was observed in the first half year. Length of stay was not associated with age. It was concluded that age is an important determining factor for functional outcome after SCI and that elderly patients have difficulties in translating an improvement in neurological outcome into functional changes. Therefore, rehabilitation approaches in elderly subjects should focus on functional training.