scholarly journals Proximal arm non-use optimises movement when the shoulder is weak: consequences for stroke patients

2020 ◽  
Author(s):  
Germain Faity ◽  
Denis Mottet ◽  
Simon Pla ◽  
Jérôme Froger
Keyword(s):  
Optimal Control ◽  
Muscular Strength ◽  
Control Policy ◽  
Human Movement ◽  
High Gravity ◽  
Stroke Patients ◽  
Constraint Induced Movement Therapy ◽  
Paretic Limb ◽  
High Gravity Field ◽  
Healthy Participants

AbstractMost stroke patients do not use their paretic limb whereas they are able to. The Constraint-Induced Movement Therapy (CIMT) is effective to reverse this non-use behaviour in some patients but is inapplicable or unsuccessful on others. Here, we investigate how much non-use could come from shoulder weakness instead of the behavioural conditioning treated by the CIMT. We asked 26 healthy participants to reach a target while holding a dumbbell. We found that 18/26 participants exhibit proximal arm non-use when loaded and that non-use reduces shoulder torque of final posture. We either found that non-use improves accuracy in a high gravity field. Following optimal control policy, we explain how the non-use could be an adaptative solution when the shoulder is weak. Our results show the need to include muscular strength into cost function used to model human movement. The framework presented here suggests that psychological non-use could be treated effectively with CIMT, while physiological non-use, resulting from shoulder weakness, might respond better to anti-gravity muscles strengthening.

scholarly journals Impacts of Stroke on Muscle Perceptions and Relationships with the Motor and Functional Performance of the Lower Extremities

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4740
Author(s):  
Wan-Ju Liu ◽  
Li-Fong Lin ◽  
Shang-Lin Chiang ◽  
Liang-Hsuan Lu ◽  
Chao-Ying Chen ◽  
...  
Keyword(s):  
Functional Performance ◽  
Absolute Error ◽  
Stroke Patients ◽  
Functional Changes ◽  
Direction Error ◽  
Paretic Limb ◽  
Mobility Assessment ◽  
Postural Assessment ◽  
Flexor Digitorum ◽  
Healthy Participants

Stroke results in paretic limb disabilities, but few studies have investigated the impacts of stroke on muscle perception deficits in multiaxis movements and related functional changes. Therefore, this study aimed to investigate stroke-related changes in muscle perceptions using a multiaxis ankle haptic interface and analyze their relationships with various functions. Sixteen stroke patients and 22 healthy participants performed active reproduction tests in multiaxis movements involving the tibialis anterior (TA), extensor digitorum longus (EDL), peroneus longus, and flexor digitorum longus (FDL) of the ankle joint. The direction error (DE), absolute error (AE), and variable error (VE) were calculated. The lower extremity of Fugl-Meyer Assessment (FMA-LE), Barthel Index (BI), Postural Assessment Scale for Stroke Patients, Tinetti Performance-Oriented Mobility Assessment (POMA), and 10-m walk test (10MWT) were evaluated. VE of EDL for the paretic ankle was significantly lower than that for the nonparetic ankle (p = 0.009). AE of TA, EDL, and FDL and VE of EDL and FDL of muscle perceptions were significantly lower in healthy participants than in stroke patients (p < 0.05 for both). DE of TA for the paretic ankle was moderately correlated with FMA-LE (r = −0.509) and POMA (r = −0.619) scores. AE and VE of EDL for the paretic ankle were moderately correlated with the 10MWT score (r = 0.515 vs. 0.557). AE of FDL for the paretic ankle was also moderately correlated with BI (r = −0.562). This study indicated poorer accuracy and consistency in muscle perception for paretic ankles, which correlated with lower limb functions of stroke patients.

scholarly journals Nitrogen-Doped Graphene Foam as a Metal-Free Catalyst for Reduction Reactions under a High Gravity Field

Engineering ◽  
2020 ◽  
Vol 6 (6) ◽  
pp. 680-687 ◽  
Author(s):  
Zhiyong Wang ◽  
Zhijian Zhao ◽  
Jesse Baucom ◽  
Dan Wang ◽  
Liming Dai ◽  
...  
Keyword(s):  
Gravity Field ◽  
High Gravity ◽  
Graphene Foam ◽  
Reduction Reactions ◽  
Nitrogen Doped ◽  
Metal Free ◽  
Nitrogen Doped Graphene ◽  
Doped Graphene ◽  
High Gravity Field

scholarly journals Mathematical Modeling and Optimal Control of the Hand Foot Mouth Disease Affected by Regional Residency in Thailand

Mathematics ◽  
2021 ◽  
Vol 9 (22) ◽  
pp. 2863
Author(s):  
Napasool Wongvanich ◽  
I-Ming Tang ◽  
Marc-Antoine Dubois ◽  
Puntani Pongsumpun
Keyword(s):  
Optimal Control ◽  
Numerical Solutions ◽  
Foot And Mouth Disease ◽  
Control Policy ◽  
Mouth Disease ◽  
Sensitivity Analyses ◽  
Urban Region ◽  
Control Parameters ◽  
Control Effort ◽  
Logarithmic Relationship

Hand, foot and mouth disease (HFMD) is a virulent disease most commonly found in East and Southeast Asia. Symptoms include ulcers or sores, inside or around the mouth. In this research, we formulate the dynamic model of HFMD by using the SEIQR model. We separated the infection episodes where there is a higher outbreak and a lower outbreak of the disease associated with regional residency, with the higher level of outbreak occurring in the urban region, and a lower outbreak level occurring in the rural region. We developed two different optimal control programs for the types of outbreaks. Optimal Control Policy 1 (OPC1) is limited to the use of treatment only, whereas Optimal Control Policy 2 (OPC2) includes vaccination along with the treatment. The Pontryagin’s maximum principle is used to establish the necessary and optimal conditions for the two policies. Numerical solutions are presented along with numerical sensitivity analyses of the required control efforts needed as the control parameters are changed. Results show that the time tmax required for the optimal control effort to stay at the maximum amount umax exhibits an intrinsic logarithmic relationship with respect to the control parameters.

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