Improved gait adjustments after gait adaptability training are associated with reduced attentional demands in persons with stroke

Abstract

After stroke, the ability to make step adjustments during walking is reduced and requires more attention, which may cause problems during community walking. The C-Mill is an innovative treadmill augmented with visual context (e.g., obstacles and stepping targets), which was designed specifically to practice gait adaptability. The objective of this study was to determine whether C-Mill gait adaptability training can help to improve gait adjustments and associated attentional demands. Sixteen community-ambulating persons in the chronic stage of stroke (age: 54.8 ± 10.8 years) received ten sessions of C-Mill training within 5-6 weeks. Prior to and after the intervention period, participants performed an obstacle-avoidance task with and without a secondary attention-demanding auditory Stroop task to assess their ability to make gait adjustments (i.e., obstacle-avoidance success rates) as well as the associated attentional demands (i.e., Stroop success rates, stratified for pre-crossing, crossing, and post-crossing strides). Obstacle-avoidance success rates improved after C-Mill training from 52.4 ± 16.3 % at pretest to 77.0 ± 16.4 % at posttest (p < 0.001). This improvement was accompanied by greater Stroop success rates during the obstacle-crossing stride only (pretest: 62.9 ± 24.9 %, posttest: 77.5 ± 20.4 %, p = 0.006). The observed improvements in obstacle-avoidance success rates and Stroop success rates were strongly correlated (r = 0.68, p = 0.015). The ability to make gait adjustments and the associated attentional demands can be successfully targeted in persons with stroke using C-Mill training, which suggests that its underlying assumptions regarding motor control are appropriate. This study lends support and guidance for designing a randomized controlled trial to further examine the potential of C-Mill training for improving safe community ambulation after stroke.

Walking adaptability therapy after stroke: study protocol for a randomized controlled trial

“…C-Mill therapy is a structured treadmill training program with a specific emphasis on practicing walking adaptability (as detailed in Table 1 and Additional file 1), using gait-dependent augmented-reality content projected on the instrumented treadmill surface to elicit step adjustments [1, 13–15, 25–28]. Figure 3 shows various exercises of C-Mill therapy, including exercises to practice avoidance of projected visual obstacles (Fig.…”

“…The secondary outcome measures are inspired by the targeted-stepping and obstacle-avoidance results of Hollands et al [35] and Van Ooijen et al [15], underscoring the importance of task-specificity and context-specificity in walking adaptability assessments. Van Ooijen et al [15] showed enhanced obstacle-avoidance success rates at lower attentional costs after a period of C-Mill walking adaptability therapy, while Hollands et al [35] showed that measures of targeted stepping were clinically meaningful components in the recovery of functional mobility after stroke.…”

“…Van Ooijen et al [15] showed enhanced obstacle-avoidance success rates at lower attentional costs after a period of C-Mill walking adaptability therapy, while Hollands et al [35] showed that measures of targeted stepping were clinically meaningful components in the recovery of functional mobility after stroke. Therefore, the 10 Meter Walking Test will also be performed in combination with context (10 Meter Walking Test with three obstacles, a tandem walking path and three stepping targets) (Fig.…”

“…C-Mill therapy resulted in training-related increments in walking speed and improvements in various other walking-related clinical scores. In addition, the ability to make step adjustments improved (i.e., higher obstacle-avoidance success rates) after 5–6 weeks of C-Mill therapy, and these adjustments required less attention (i.e., reduced dual-task interference), suggesting that the step adjustments evolved in a more automatized manner after a period of C-Mill therapy [15]. …”

“…The study’s aim is to compare the effects of two promising interventions for improving walking speed, walking adaptability, and commonly used clinical measures of walking and balance in persons after stroke: treadmill-based C-Mill therapy [14, 15] and the overground FALLS program [9]. We expect that C-Mill therapy will result in better outcomes than the FALLS program because of the expected greater amount of walking practice per session of equal duration.…”