The efects of an object’s height and weight on force calibration and kinematics when post‑stroke and healthy individuals reach and grasp

18 pages in total for your doctor to analyze and implement. These are obviously high functioning individuals already. I have zero grasping ability and very distorted reaching, both problems as a result of spasticity.  You have to cure spasticity first before this helps most survivors.

The efects of an object’s height and weight on force calibration and kinematics when post‑stroke and healthy individuals reach and grasp

 p Ronit Feingold‑Polak1,6, AnnaYelkin1,2,6, Shmil Edelman3 , Amir Shapiro3 & Shelly Levy‑Tzedek1,4,5* 

Impairment in force regulation and motor control impedes the independence of individuals with stroke by limiting their ability to perform daily activities. There is, at present, incomplete information about how individuals with stroke regulate the application of force and control their movement when reaching, grasping, and lifting objects of diferent weights, located at diferent heights. In this study, we assess force regulation and kinematics when reaching, grasping, and lifting a cup of two diferent weights (empty and full), located at three diferent heights, in a total of 46 participants: 30 sub-acute stroke participants, and 16 healthy individuals. We found that the height of the reached target afects both force calibration and kinematics, while its weight afects only the force calibration when poststroke and healthy individuals perform a reach-to-grasp task. There was no diference between the two groups in the mean and peak force values. The individuals with stroke had slower, jerkier, less efcient, and more variable movements compared to the control group. This diference was more pronounced with increasing stroke severity. With increasing stroke severity, post-stroke individuals demonstrated altered anticipation and preparation for lifting, which was evident for either cortical lesion side. Upper limb function following stroke. Cerebrovascular accidents (CVAs) are a leading cause of longterm disability worldwide1 , leaving up to 75% of survivors with persistent upper limb (UL) sensorimotor defcits2,3 . Impaired UL function post-stroke signifcantly impedes ability to perform activities of daily living (ADLs) such as reaching, picking up, and holding objects4 . Tese defcits limit performance and social participation, negatively afecting quality of life3,5–7 . Reach‑to‑grasp movement in healthy and post‑stroke individuals. Reach-to-grasp (RTG) movements are a primary means of interacting with the environment, allowing people to obtain and manipulate objects around them8 . RTG movement entails both the transport component, which is the change in position of the hand over time, and the grasp component9 . Both are synchronized such that the hand opens and closes, in coordination with hand movements when grasping objects10. RTG movements require precise application of grip forces11, e.g., when we move our arm while holding an object between our fngers, we unconsciously increase the grip forces to prevent the object from slipping12 or sliding13. Skilled grip force relies on prediction and sensory feedback14, such that during a grip-lif task, healthy individuals are able to rapidly establish an association between an arbitrary sensory cue with a given weight and scale grip force precisely to the actual OPEN 1 Department of Physical Therapy, Recanati School for Community Health Professions, Ben-Gurion University of the Negev, Ben‑Gurion Blvd, Beer‑Sheva, Israel. 2 Beit Hadar Rehabilitation Center, Ashdod, Israel. 3 Department of Mechanical Engineering, Ben-Gurion University of the Negev, Beer‑Sheva, Israel. 4 Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer‑Sheva, Israel. 5 Freiburg Institute for Advanced Studies (FRIAS), University of Freiburg, Freiburg, Germany. 6These authors contributed equally: Ronit Feingold-Polak and Anna Yelkin. *email: shelly@bgu.ac.i