Kinematic analysis of motor learning in upper limb body-powered bypass prosthesis training.

Motor learning and compensatory movement are important aspects of prosthesis training yet relatively little quantitative evidence supports our current understanding of how motor control and compensation develop in the novel body-powered prosthesis user. The goal of this study is to assess these aspects of prosthesis training through functional, kinematic, and kinetic analyses using a within-subject paradigm compared across two training time points. The joints evaluated include the left and right shoulders, torso, and right elbow. Six abled-bodied subjects (age 27 ± 3) using a body-powered bypass prosthesis completed the Jebsen-Taylor Hand Function Test and the targeted Box and Blocks Test after five training sessions and again after ten sessions. Significant differences in movement parameters included reduced times to complete tasks, reduced normalized jerk for most joints and tasks, and more variable changes in efficiency and compensation parameters for individual tasks and joints measured as range of motion, maximum angle, and average moment. Normalized jerk, joint specific path length, range of motion, maximum angle, and average moment are presented for the first time in this unique training context and for this specific device type. These findings quantitatively describe numerous aspects of motor learning and control in able-bodied subjects that may be useful in guiding future rehabilitation and training of body-powered prosthesis users

Application of machine learning to the identification of joint degrees of freedom involved in abnormal movement during upper limb prosthesis use.

To evaluate movement quality of upper limb (UL) prosthesis users, performance-based outcome measures have been developed that examine the normalcy of movement as compared to a person with a sound, intact hand. However, the broad definition of "normal movement" and the subjective nature of scoring can make it difficult to know which areas of the body to evaluate, and the expected magnitude of deviation from normative movement. To provide a more robust approach to characterizing movement differences, the goals of this work are to identify degrees of freedom (DOFs) that will inform abnormal movement for several tasks using unsupervised machine learning (clustering methods) and elucidate the variations in movement approach across two upper-limb prosthesis devices with varying DOFs as compared to healthy controls. 24 participants with no UL disability or impairment were recruited for this study and trained on the use of a body-powered bypass (n = 6) or the DEKA limb bypass (n = 6) prosthetic devices or included as normative controls. 3D motion capture data were collected from all participants as they performed the Jebsen-Taylor Hand Function Test (JHFT) and targeted Box and Blocks Test (tBBT). Range of Motion, peak angle, angular path length, mean angle, peak angular velocity, and number of zero crossings were calculated from joint angle data for the right/left elbows, right/left shoulders, torso, and neck and fed into a K-means clustering algorithm. Results show right shoulder and torso DOFs to be most informative in distinguishing between bypass user and norm group movement. The JHFT page turning task and the seated tBBT elicit movements from bypass users that are most distinctive from the norm group. Results can be used to inform the development of movement quality scoring methodology for UL performance-based outcome measures. Identifying tasks across two different devices with known variations in movement can inform the best tasks to perform in a rehabilitation setting that challenge the prosthesis user's ability to achieve normative movement

Dispositional negativity in the wild: Social environment governs momentary emotional experience

Dispositional negativity—the tendency to experience more frequent or intense negative emotions—is a fundamental dimension of temperament and personality. Elevated levels of dispositional negativity have profound consequences for public health and wealth, drawing the attention of researchers, clinicians, and policy makers. Yet, relatively little is known about the factors that govern the momentary expression of dispositional negativity in the real world. Here, we used smart phone-based experience-sampling to demonstrate that the social environment plays a central role in shaping the moment-by-moment emotional experience of 127 young adults selectively recruited to represent a broad spectrum of dispositional negativity. Results indicate that individuals with a more negative disposition derive much larger emotional benefits from the company of close companions—friends, romantic partners, and family members—and that these benefits reflect heightened feelings of social connection and acceptance. These results set the stage for developing improved interventions and provide new insights into the interaction of emotional traits and situations in the real world, close to clinically and practically important endpoints

Dispositional Negativity in the Wild: Social Environment Governs Momentary Emotional Experience

Dispositional negativity-the tendency to experience more frequent or intense negative emotions-is a fundamental dimension of temperament and personality. Elevated levels of dispositional negativity have profound consequences for public health and wealth, drawing the attention of researchers, clinicians, and policymakers. Yet, relatively little is known about the factors that govern the momentary expression of dispositional negativity in the real world. Here, we used smart phone-based experience-sampling to demonstrate that the social environment plays a central role in shaping the moment-by-moment emotional experience of 127 young adults selectively recruited to represent a broad spectrum of dispositional negativity. Results indicate that individuals with a more negative disposition derive much larger emotional benefits from the company of close companions-friends, romantic partners, and family members-and that these benefits reflect heightened feelings of social connection and acceptance. These results set the stage for developing improved interventions and provide new insights into the interaction of emotional traits and situations in the real world, close to clinically and practically important end-points. (PsycINFO Database Recor