Seated postural organization during bilateral upper limb symmetric and asymmetric pushing tasks in individuals after stroke compared to healthy controls.

BACKGROUND: Asymmetric weight distribution in sitting has been reported in people after stroke. However, postural strategies used during bilateral symmetric and asymmetric movements performed while seated require more evidence to inform rehabilitation strategies. RESEARCH QUESTIONS: How do symmetric and asymmetric effort levels exerted during upper limb (UL) pushing movements affect seated postural organization parameters (weight bearing (WB) between hands and hemibody sides, and forward trunk displacement) of stroke compared to healthy individuals? How are these parameters associated? METHODS: Using an instrumented exerciser, 19 post-stroke individuals were compared to 17 healthy individuals when executing four bilateral UL pushing movements in a seated position: symmetrical pushing at 30 % and 15 % of their maximal force (MF) and asymmetrical pushing with 15 % of their MF for one UL vs. 30 % of the MF for the other UL and vice versa. Anterior and vertical forces of the push, as well as vertical forces under each foot and thigh were compared between groups, sides and conditions. Forward trunk displacement was compared between groups and conditions. Correlations were used to determine the association between trunk displacement, hands and hemibody vertical forces. RESULTS: Increasing pushing effort caused increased WB on thighs and decreased on WB on feet during the 30 % MF symmetric condition compared to the 15 % MF and asymmetric conditions (p < 0.05). Individuals post-stroke showed WB asymmetry and greater forward trunk displacement when compared to healthy persons (p < 0.05). For both groups, hemibody WB and trunk displacement showed moderate association (r > - 0.5) in the asymmetric condition executed with more resistance on the paretic or non-dominant hand. SIGNIFICANCE: Individuals post-stroke presented a similar WB pattern to that of healthy persons during symmetric and asymmetric bilateral UL movements with greater forward trunk displacement and asymmetry. Increased effort and asymmetric force between both UL had effects on seated postural organization strategy.

What can Designing Learning-by-Concordance Clinical Reasoning Cases Teach Us about Instruction in the Health Sciences?

Introduction: Learning-by-concordance (LbC) is an online learning strategy to practice reasoning skills in clinical situations. Writing LbC clinical cases, comprising an initial hypothesis and supplementary data, differs from typical instructional design. We sought to gain a deeper understanding from experienced LbC designers to better support clinician educators' broader uptake of LbC. Methods: A dialogic action research approach was selected because it yields triangulated data from a heterogeneous group. We conducted three 90-minute dialogue-group sessions with eight clinical educators. Discussions focused on the challenges and pitfalls of each LbC design stage described in the literature. Recordings were transcribed and analyzed thematically. Results: We identified three themes by thematic analysis about the challenges inherent in designing LbC that are unique for this type of learning strategy: 1) the distinction between pedagogical intent and learning outcome; 2) the contextual cues used to challenge students and advance their learning and 3) the integration of experiential with formalized knowledge for cognitive apprenticeship. Discussion: A clinical situation can be experienced and conceptualized in many ways, and multiple responses are appropriate. LbC designers use contextual cues from their experience and combine them with formalized knowledge and protocols to write effective LbC clinical reasoning cases. LbC focuses learners' attention on decision-making in grey areas that characterize the nature of professional clinical work. This in-depth study on LbC design, indicating the integration of experiential knowledge, might call for new thinking about instructional design.

Bilateral motor coordination during upper limb symmetric pushing movements at two levels of force resistance in healthy and post-stroke individuals.

BACKGROUND: Impairments of the upper limb (UL) are common after a stroke and may affect bilateral coordination. A better understanding of UL bilateral coordination is required for designing innovative rehabilitation strategies. OBJECTIVE: To assess bilateral coordination after stroke using time-distance, velocity and force parameters during an UL bilateral task performed by simultaneously pushing handles on a bilateral exerciser at two levels of force. METHODS: Two groups were included to assess bilateral coordination on a newly designed bimanual exerciser- One group of individuals at least 3 months post-stroke (n = 19) with moderate impairment and one group of healthy individuals (n = 20). Participants performed linear movements by pushing simultaneously with both hands on instrumented handles. The task consisted of two one-minute trials performed in sitting at two levels of participants' maximum force (MF): 30% and 15%, with visual feedback. Time-distance parameters, spatial, velocity and force profiles were compared between groups, between levels of resistance and the first part (0-50%) and entire duration of the pushing cycles (0-100%). RESULTS: The mean pushing time was longer at 30% MF compared to 15% MF in the stroke group. Spatial profiles, represented by hand positions on the rail, revealed that the paretic hand lagged slightly behind throughout the cycle. For velocity, both groups displayed good coordination. It was less coupled at 30% than 15% MF and a trend was observed toward more lag occurrence in the stroke group. Except for lower forces on the paretic side in the stroke group, the shape of the force profiles was similar between groups, sides and levels of resistance. For all parameters, the coordination was good up to 75% of the pushing cycle and decreased toward the end of the cycle. CONCLUSIONS: Individuals after stroke presented with overall spatial and temporal coupling of the UL during bilateral pushing movements. The relay of information at different levels of the nervous system might explain the coordinated pushing movements and might be interesting for training UL coordination.

Cerebellar Transcranial Direct Current Stimulation in Children with Developmental Coordination Disorder: A Randomized, Double-Blind, Sham-Controlled Pilot Study.

Evidence-based therapeutic options for children with developmental coordination disorder (DCD) are scarce. This work explored the effects of cerebellar anodal transcranial direct current stimulation (atDCS) on three 48 h-apart motor sequence learning and upper limb coordination sessions in children with DCD. The results revealed that, as compared to a Sham intervention (n = 10), cerebellar atDCS (n = 10) did not meaningfully improve execution speed but tended to reduce the number of execution errors during motor sequence learning. However, cerebellar atDCS did neither meaningfully influence offline learning nor upper limb coordination, suggesting that atDCS' effects are circumscribed to its application duration. These results suggest that cerebellar atDCS could have beneficial effects as a complementary therapeutic tool for children with DCD.

Postural organization and inter-limb coordination are altered after stroke when an isometric maximum bilateral pushing effort of the upper limbs is performed.

BACKGROUND: Postural strategies of the trunk and the lower limbs are linked to upper limb motor activities. The objective was to analyze the postural organization at the lower limbs as well as the inter-limb coordination during isometric maximal bilateral pushing of upper limbs. METHODS: Fifteen individuals after stroke and 17 healthy participants were assessed with an instrumented exerciser paired with an instrumented sitting surface while they executed isometric bilateral pushes with the upper limbs. The anteroposterior, vertical and mediolateral forces were recorded at the handles, the thighs and the feet. Force values at maximal bilateral pushing efforts at each segment and inter-limb coordination between sides were compared. FINDINGS: During the isometric pushes, the paretic maximal forces at the handles for stroke participants were lower than the nonparetic side and lower than both sides of the control participants (p < 0.036). The control and stroke participants had moderate to good coordination for the anteroposterior forces (hands and thighs). While they used similar postural strategies to the controls except for a decreased weight on the paretic foot, vertical forces were less coordinated at the handles and feet in the stroke group (p < 0.050). The inter-trial variability was also higher in the stroke group. INTERPRETATION: Bilateral pushing with gradual efforts induces impaired postural strategies and coordination between limbs in individuals after stroke. It may reveal to be a promising strategy to assess and train post-stroke individuals in a clinical setting. Also, providing feedback would help better control symmetry during efforts.