Characterizing the Longitudinal Impact of Backward Locomotor Treadmill Training on Walking and Balance Outcomes in Chronic Stroke Survivors: A Randomized Single Center Clinical Trial

Abstract

Background and purpose: Walking and balance impairments after stroke are a global health concern, causing significant morbidity and mortality. However, effective strategies for achieving meaningful recovery in the chronic stages are limited. Backward locomotor treadmill training (BLTT) is a novel walking rehabilitation protocol that is safe, feasible, and likely beneficial in stroke survivors; however, its efficacy has not been tested. This single-center, randomized, assessor-blind clinical trial aims to test the preliminary efficacy of BLTT compared to forward locomotor treadmill training (FLTT) on walking speed, symmetry, and postural stability.

Methods: Forty stroke survivors [BLTT (N=19), FLTT (N=21); mean age= 56.3 ± 8.6 years; 53% Female; 30% Non-Hispanic Black] with mild-moderate walking impairment were enrolled. Participants underwent nine 30-minute BLTT or FLTT sessions over three weeks. The primary outcome was the mean change in the 10-meter walk test (10 MWT) at 24 hours post-training (24 hr POST). Secondary outcome measures were changes in spatiotemporal walking symmetry and postural stability during quiet standing at 24 hr POST. Retention was explored at Days 30- and 90 POST.

Results: We report clinically meaningful (≥ 0.16 m/s) improvements in overground walking speed at 24 hr POST, with retention up to Day 90 POST with BLTT and FLTT. However, contrary to our working hypothesis, no between-group differences in walking speed were observed. Nonetheless, we found that BLTT resulted in offline improvements in spatial symmetry and retention of subcomponents of the modified clinical test of sensory interaction on balance (mCTSIB), including the testing of proprio-vestibular integration up to Day 30 POST.

Conclusion: Among chronic stroke patients with mild-moderate walking impairment, BLTT and FLTT both resulted in long-lasting and clinically meaningful improvement in walking speed. However, preliminary findings suggest that BLTT may better comprehensively target walking asymmetry and sensory systems processing and integration.

Keywords: Backward Walking; Balance; Gait; Outcome Measures; Postural Stability; Sensorineural Integration; Stroke; Stroke Recovery; Stroke Rehabilitation; Walking.

Figure 1.

Study Schematic: 10 MWT (10-meter walk Test); FP (Fast-Paced); mCTSIB- modified Clinical test of Sensory Interaction in Balance; BLTT (backward locomotion treadmill training); FLTT (forward locomotion treadmill training

Figure 2.

Trial Profile

Figure 3.

Fast Walking Speed. Mean walking 10-meter walk test (10MWT) speed pre-90 days post-training (A), represented as the mean and standard error measure. Retention of walking speed post-training, 30- and 90-days post-training, with 0.16 m/s (dotted line) as references for the minimal clinically important difference (MCID), (B). Squares represent individual participant data at each time point. ****p<0.0001

Figure 4.

Spatiotemporal Symmetry Index. Step Length Symmetry(A) % Single Support Time Symmetry (B) represents the mean and standard error measure. *p<0.05.

Figure 5.

Sway Velocity Index [SVI) on the modified Clinical test of Sensory Interaction in Balance of the Balance Platform Biodex Balance System^™, represented as the mean and standard error measure. The dotted lines represent normative data for each condition. *p<0.05, **p<0.01, ***p<0.001, ****p<0.0001