Nutrient supplementation post ambulation in persons with incomplete spinal cord injuries: a randomized, double-blinded, placebo-controlled case series.

OBJECTIVE: To examine effects of protein-carbohydrate intake on ambulation performance in persons with incomplete spinal cord injury (SCI). DESIGN: Double-blinded treatment with washout and placebo crossover. SETTING: Academic medical center. PARTICIPANTS: Three subjects aged 34 to 43 years with incomplete SCI at C5-T4. INTERVENTIONS: Subjects walked to fatigue on 5 consecutive days. On fatigue, participants consumed 48g of vanilla-flavored whey and 1g/kg of body weight of carbohydrate (CH(2)O). Weekend rest followed, and the process was repeated. A 2-week washout was interposed and the process repeated using 48g of vanilla-flavored soy. MAIN OUTCOME MEASURES: Oxygen consumed (Vo(2); in L/min), carbon dioxide evolved (Vco(2)), respiratory exchange ratio (RER: Vco(2)/Vo(2)), time (in minutes), and distance walked (in meters) were recorded. Caloric expenditure was computed as Vo(2) by time by 21kJ/L (5kcal/L) of oxygen consumed. Data were averaged across the final 2 ambulation sessions for each testing condition. RESULTS: Despite slow ambulation velocities (range, .11-.34m/s), RERs near or above unity reflected reliance on CH(2)O fuel substrates. Average ambulation time to fatigue was 17.8% longer; distance walked 37.9% longer, and energy expenditure 12.2% greater with the whey and CH(2)O supplement than with the soy drink. CONCLUSIONS: Whey and CH(2)O ingestion after fatiguing ambulation enhanced ensuing ambulation by increasing ambulation distance, time, and caloric expenditure in persons with incomplete SCI.

Influence of posture and stimulus parameters on post-activation depression of the soleus H-reflex in individuals with chronic spinal cord injury.

In non-disabled (ND) individuals, reflexes are modulated by influences related to physiologic state (e.g., posture, joint position, load) and activation history. Repeated activation of the H-reflex results in post-activation depression (PAD) of the response amplitude. The modulation associated with physiologic state and activation history is suppressed or abolished in individuals with spinal cord injury (SCI). While posture is known to affect H-reflex amplitude and PAD in non-disabled individuals, the effect of posture on PAD in SCI individuals is not known. Further, while the amount of PAD is also known to be influenced by the stimulus rate and by the amplitude of the evoked reflex, the interaction of posture with stimulus parameters has not been previously investigated in either group. We investigated differences in PAD of the soleus H-reflex between SCI subjects and ND subjects during sitting versus supported standing. Subjects were tested using paired conditioning-test stimulus pulses of 2.5s and 5s interpulse intervals (ISI) and with stimulus intensity adjusted to evoke reflex responses of 20% and 40% of the maximum motor response. We found standing posture to be associated with significantly less PAD in SCI subjects compared to ND subjects. In both groups, shorter ISIs and smaller reflex amplitudes were associated with greater PAD of the H-reflex. These results indicate that postural influences on post-activation modulation, while present, are impaired in individuals with chronic incomplete SCI.

Locomotor training approaches for individuals with spinal cord injury: a preliminary report of walking-related outcomes.

BACKGROUND AND PURPOSE: Body weight supported (BWS) locomotor training improves overground walking ability in individuals with motor-incomplete spinal cord injury (SCI). While there are various approaches available for locomotor training, there is no consensus regarding which of these is optimal. The purpose of this ongoing investigation is to compare outcomes associated with these different training approaches. SUBJECTS AND METHODS: Twenty-seven subjects with chronic motor-incomplete SCI have completed training and initial and final testing at the time of this preliminary report. Subjects were randomly assigned to 1 of 4 different BWS assisted-stepping groups, including: (1) treadmill training with manual assistance (TM), (2) treadmill training with stimulation (TS), (3) overground training with stimulation (OG), or (4) treadmill training with robotic assistance (LR). Prior to and following participation we assessed walking-related outcome measures including overground walking speed, training speed, step length, and step symmetry. RESULTS: Data pooled across all subject groups showed a significant effect of training on walking speed. While the differences between groups were not statistically significant, there was a trend toward greater improvement in the TS and OG groups. Post hoc subgroup analysis of outcomes from subjects with slower initial walking speed (< 0.1 m/s; n = 15) compared to those with faster initial walking speeds (> or = 0.1 m/s; n = 12) identified meaningful differences in outcomes with walking speed increasing by 85% in the slower group and by only 9% in the faster group. Step length of both stronger and weaker limb increased in all groups with the exception of those in the LR group. Step symmetry was increased in the TM and LR groups. DISCUSSION AND CONCLUSION: These results represent preliminary findings of changes in walking-related function associated with different forms of BWS locomotor training for individuals with chronic, motor-incomplete SCI. Early data indicates that locomotor outcomes in these individuals appear to be comparable across training approaches. For the individuals in this study sample, those with the greatest deficits in walking function benefitted the most from locomotor training.