LAUSR

OBJECTIVE To describe the effect of robotic locomotor training (RLT) and activity-based training (ABT) on cardiovascular indices during various physiological perturbations in individuals with SCI. DESIGN Randomized controlled pilot study SETTING: Private practice: Therapy & Beyond Centre - Walking with Brandon Foundation, Sports Science Institute of South Africa, Cape Town, South Africa. PARTICIPANTS 16 participants with chronic traumatic motor incomplete tetraplegia who resided in the Western Cape, South Africa INTERVENTIONS: Robotic locomotor training (Ekso GT) and activity-based training over a 24-week intervention. MAIN OUTCOME MEASURES Brachial and ankle blood pressure, heart rate, heart rate variability, cardiovascular efficiency during four physiological perturbations. RESULTS No differences between groups or over time were evident in resting systolic and diastolic blood pressure, ankle systolic pressure, ankle brachial pressure index and heart rate variability. Standing heart rate at 24-weeks was significantly higher in the ABT group (95.58 ± 12.61 beats/min) compared to the RLT group (75.14 ± 14.96 beats/min) (p = 0.05). In the RLT group, no significant changes in heart rate variability (standard deviation R-R interval and root mean square of successive differences) was found between the standing and 6-minute walk test physiological perturbations throughout the intervention. Cardiovascular efficiency in the RLT group during the 6-minute walk test improved from 11.1 ± 2.6 at baseline to 7.5 ± 2.8 beats per metre walked at 6-weeks, and was maintained from 6 to 24-weeks. CONCLUSIONS Large effect sizes and significant differences between groups found in this pilot study support the clinical effectiveness of RLT and ABT for changing cardiovascular indices as early as 6-weeks and up to 24-weeks of rehabilitation. RLT may be more effective than ABT in improving cardiac responses to orthostatic stress. Based on heart rate variability metrics, the stimulus of standing has comparable effects to RLT on the parasympathetic nervous system. Cardiovascular efficiency of exoskeleton walking improved, particularly over the first 6-weeks. Both the RLT and ABT interventions were limited in their effect on brachial and ankle blood pressure. A RCT with a larger sample size is warranted to further examine these findings.