Shoulder abduction loading affects motor coordination in individuals with chronic stroke, informing targeted rehabilitation

Individuals post stroke experience motor impairments, such as loss of independent joint control, weakness, and delayed movement initiation, leading to an overall reduction in arm function. Their motion becomes slower and more discoordinated, making it difficult to complete timing-sensitive tasks, such as balancing a glass of water or carrying a bowl with a ball inside it. Understanding how the stroke-induced motor impairments interact with each other can help design assisted training regimens for improved recovery. In this study, we investigate the effects of abnormal joint coupling patterns induced by flexion synergy on timing-sensitive motor coordination in the paretic upper limb. We design a virtual ball-in-bowl task that requires fast movements for optimal performance and implement it on a robotic system, capable of providing varying levels of abduction loading at the shoulder. We recruit 12 participants (6 individuals with chronic stroke and 6 unimpaired controls) and assess their skill at the task at 3 levels of loading, defined by the vertical force applied at the robot end-effector. Our results show that, for individuals with stroke, loading has a significant effect on their ability to generate quick coordinated motion. With increases in loading, their overall task performance decreases and they are less able to compensate for ball dynamics—frequency analysis of their motion indicates that abduction loading weakens their ability to generate movements at the resonant frequency of the dynamic task. This effect is likely due to an increased reliance on lower resolution indirect motor pathways in individuals post stroke. Given the inter-dependency of loading and dynamic task performance, we can create targeted robot-aided training protocols focused on improving timing-sensitive motor control, similar to existing progressive loading therapies, which have shown efficacy for expanding reachable workspace post stroke.

[1]  J. Dewald,et al.  Progressive Shoulder Abduction Loading is a Crucial Element of Arm Rehabilitation in Chronic Stroke , 2009, Neurorehabilitation and neural repair.

[2]  J. Dewald,et al.  Shoulder abduction-induced reductions in reaching work area following hemiparetic stroke: neuroscientific implications , 2007, Experimental Brain Research.

[3]  Manin H. Konijnenbelt,et al.  Proprioception of the shoulder after stroke. , 2008, Archives of physical medicine and rehabilitation.

[4]  P. Morasso,et al.  Self-adaptive robot training of stroke survivors for continuous tracking movements , 2010, Journal of NeuroEngineering and Rehabilitation.

[5]  W. Rymer,et al.  Abnormal muscle coactivation patterns during isometric torque generation at the elbow and shoulder in hemiparetic subjects. , 1995, Brain : a journal of neurology.

[6]  H. van der Kooij,et al.  An explorative study into changes in circle drawing after gravity compensation training in chronic stroke patients , 2011, 2011 IEEE International Conference on Rehabilitation Robotics.

[7]  J. Nilsson,et al.  Arm weight support training improves functional motor outcome and movement smoothness after stroke. , 2014, Functional neurology.

[8]  C. Ghez,et al.  Loss of proprioception produces deficits in interjoint coordination. , 1993, Journal of neurophysiology.

[9]  J. Dewald,et al.  Task-dependent weakness at the elbow in patients with hemiparesis. , 1999, Archives of physical medicine and rehabilitation.

[10]  T.M. Sukal,et al.  Dynamic characterization of upper limb discoordination following hemiparetic stroke , 2005, 9th International Conference on Rehabilitation Robotics, 2005. ICORR 2005..

[11]  Kathleen Fitzsimons,et al.  Ergodicity reveals assistance and learning from physical human-robot interaction , 2019, Science Robotics.

[12]  Dagmar Sternad,et al.  Predictability, force, and (anti)resonance in complex object control. , 2018, Journal of neurophysiology.

[13]  Jules P. A. Dewald,et al.  Quantifying loss of independent joint control in acute stroke with a robotic evaluation of reaching workspace , 2011, 2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[14]  Julius P. A. Dewald,et al.  Cross-Frequency Coupling in Descending Motor Pathways: Theory and Simulation , 2020, Frontiers in Systems Neuroscience.

[15]  Derek G Kamper,et al.  Effect of a gravity-compensating orthosis on reaching after stroke: evaluation of the Therapy Assistant WREX. , 2008, Archives of physical medicine and rehabilitation.

[16]  J. Dewald,et al.  Impact of gravity loading on post‐stroke reaching and its relationship to weakness , 2007, Muscle & nerve.

[17]  J. Chae,et al.  Delay in initiation and termination of muscle contraction, motor impairment, and physical disability in upper limb hemiparesis , 2002, Muscle & nerve.

[18]  Julius P A Dewald,et al.  Progressive recruitment of contralesional cortico‐reticulospinal pathways drives motor impairment post stroke , 2018, The Journal of physiology.

[19]  Julius P. A. Dewald,et al.  Position-dependent torque coupling and associated muscle activation in the hemiparetic upper extremity , 2007, Experimental Brain Research.

[20]  R. Carson,et al.  Training-induced changes in the pattern of triceps to biceps activation during reaching tasks after chronic and severe stroke , 2009, Experimental Brain Research.

[21]  Chun-Yen Chang,et al.  Study of Repetitive Movements Induced Oscillatory Activities in Healthy Subjects and Chronic Stroke Patients , 2016, Scientific Reports.

[22]  J. Dewald,et al.  Abnormal joint torque patterns in the paretic upper limb of subjects with hemiparesis , 2001, Muscle & nerve.

[23]  Kathleen Fitzsimons,et al.  Online User Assessment for Minimal Intervention During Task-Based Robotic Assistance , 2018, Robotics: Science and Systems.

[24]  Julius P. A. Dewald,et al.  Neural Plasticity in Moderate to Severe Chronic Stroke Following a Device-Assisted Task-Specific Arm/Hand Intervention , 2017, Front. Neurol..

[25]  R. E. Lrvine.  Movement Therapy in Hemiplegia: A Neurophysiological Approach , 1972 .

[26]  N. Hogan,et al.  Movement Smoothness Changes during Stroke Recovery , 2002, The Journal of Neuroscience.

[27]  J. Buurke,et al.  Influence of gravity compensation training on synergistic movement patterns of the upper extremity after stroke, a pilot study , 2012, Journal of NeuroEngineering and Rehabilitation.