Nadeau S1,2, Akremi H2,3, Aissaoui R2,4, Higgins J2,5
1University of Montreal, Physical Therapy, Montreal, Canada, 2CRIR, Montreal, Canada, 3School of Rehabilitation, Rehabilitation Sciences, Montreal, Canada, 4École de Technologie Supérieure, Département de Génie de la Production Automatisée, Montréal, Canada, 5University of Montreal, Occupational Therapy, Montreal, Canada
Background: Rehabilitation of the upper limb (UL) post-stroke represents a significant challenge with only 5% of severely affected individuals fully recovering function of their arm and hand. The ability to produce coordinated movements and force-directing tasks are important elements contributing to the accomplishment of daily activities.
Purpose: This study used a newly designed instrumented bimanual exerciser to assess the effects of an error augmentation (EA) protocol on UL bilateral coordination.
Methods: Ten individuals post-stroke (median age: 60.5 years; time post-stroke: 4 months) able to hold a handle (Chedoke hand 4/7) were assessed. The former group was compared to a 21 healthy control group (10 women, 11 men, median age; 53 years). Both groups of participants were assessed on the bimanual exerciser using an EA protocol (baseline with symmetrical resisted movement at 30% (1 min) and 15% (1 min); adaptation with asymmetrical resistance (15% and 30%: 6 min) and post-adaptation at 15% resistance (3 min)). The effects on EA protocol on end-effector kinematic parameters (duration, excursion, onset delays and handles' speed) were assessed when executing bilateral pushing movements. Statistical analyses (ANOVAs, Mann-Whitney and Wilcoxon tests; p 0.05) were used to determine the effects of each part of the EA protocol on the variables and the difference between groups.
Results: Stroke participants produced a bilateral maximal push force of 17% lower on the paretic side with respect to the contralateral side, while healthy participants had symmetrical values (median 3% difference). Stroke and healthy participants spent the same time to execute the baseline 15% pushing task (median 0.80 -1.02 sec). The range of motion for the non-paretic arm was greater than for the paretic one (34 vs 30 cm; p 0.05) while it did not differ between sides in healthy group (median 28 cm). For both groups, the asymmetric resistance (adaptation) modified the bilateral coordination with increasing onset delays between arms (median values: Healthy: 6.3% (53 ms); Stroke: 9.4% (89 ms); resisted side at 30% late compared to less resisted side). The onset delays were reversed and differed from baseline at the beginning of the post-adaptation period (post-effects) when the non-dominant (or paretic) side was resisted. Overall, post-stroke participants had greater onset delays between sides compared to healthy controls with significant difference during the adaptation period. Similar results were found for the speed parameter. The speed was higher at beginning of adaptation period on the less resisted side, and decreased gradually over time during the adaptation period. This happens more when the non-paretic side was resisted and showed a reverse effect for the post-adaptation period.
Conclusion(s): These results revealed a good coordination between sides during symmetrical resisted movement (15% and 30%) in both groups. Individuals post-stroke showed bilateral coordination pattern like healthy controls during the EA protocol. At onset, they had more difficulty to synchronize their pushing movements than healthy controls during the adaptation period.
Implications: Stroke patients can adapt their UL motion during bilateral tasks. The exerciser is relevant to learn more about UL coordination after a stroke. Future research on bilateral UL coordination is warranted.
Keywords: Innovative Technology, upper limb coordination, Stroke
Funding acknowledgements: Engineering Interactive Technologies for Rehabilitation (FRQNT) for the funding of the exerciser. Faculty of Medicine UdeM for scholarship.
Purpose: This study used a newly designed instrumented bimanual exerciser to assess the effects of an error augmentation (EA) protocol on UL bilateral coordination.
Methods: Ten individuals post-stroke (median age: 60.5 years; time post-stroke: 4 months) able to hold a handle (Chedoke hand 4/7) were assessed. The former group was compared to a 21 healthy control group (10 women, 11 men, median age; 53 years). Both groups of participants were assessed on the bimanual exerciser using an EA protocol (baseline with symmetrical resisted movement at 30% (1 min) and 15% (1 min); adaptation with asymmetrical resistance (15% and 30%: 6 min) and post-adaptation at 15% resistance (3 min)). The effects on EA protocol on end-effector kinematic parameters (duration, excursion, onset delays and handles' speed) were assessed when executing bilateral pushing movements. Statistical analyses (ANOVAs, Mann-Whitney and Wilcoxon tests; p 0.05) were used to determine the effects of each part of the EA protocol on the variables and the difference between groups.
Results: Stroke participants produced a bilateral maximal push force of 17% lower on the paretic side with respect to the contralateral side, while healthy participants had symmetrical values (median 3% difference). Stroke and healthy participants spent the same time to execute the baseline 15% pushing task (median 0.80 -1.02 sec). The range of motion for the non-paretic arm was greater than for the paretic one (34 vs 30 cm; p 0.05) while it did not differ between sides in healthy group (median 28 cm). For both groups, the asymmetric resistance (adaptation) modified the bilateral coordination with increasing onset delays between arms (median values: Healthy: 6.3% (53 ms); Stroke: 9.4% (89 ms); resisted side at 30% late compared to less resisted side). The onset delays were reversed and differed from baseline at the beginning of the post-adaptation period (post-effects) when the non-dominant (or paretic) side was resisted. Overall, post-stroke participants had greater onset delays between sides compared to healthy controls with significant difference during the adaptation period. Similar results were found for the speed parameter. The speed was higher at beginning of adaptation period on the less resisted side, and decreased gradually over time during the adaptation period. This happens more when the non-paretic side was resisted and showed a reverse effect for the post-adaptation period.
Conclusion(s): These results revealed a good coordination between sides during symmetrical resisted movement (15% and 30%) in both groups. Individuals post-stroke showed bilateral coordination pattern like healthy controls during the EA protocol. At onset, they had more difficulty to synchronize their pushing movements than healthy controls during the adaptation period.
Implications: Stroke patients can adapt their UL motion during bilateral tasks. The exerciser is relevant to learn more about UL coordination after a stroke. Future research on bilateral UL coordination is warranted.
Keywords: Innovative Technology, upper limb coordination, Stroke
Funding acknowledgements: Engineering Interactive Technologies for Rehabilitation (FRQNT) for the funding of the exerciser. Faculty of Medicine UdeM for scholarship.
Topic: Neurology: stroke; Robotics & technology; Human movement analysis
Ethics approval required: Yes
Institution: Institut de réadaptation Gingras-Lindsay
Ethics committee: Comité d''éthique des établissements du CRIR
Ethics number: CRIR-1202-0117
All authors, affiliations and abstracts have been published as submitted.
