Revealing Key Movement Strategies in Upper Limb Function Using a Novel Standardized Kinematic Assessment Tool

  • Author / Creator
    Valevicius, Aïda
  • Introduction: Artificial limbs, also known as prostheses, are used by individuals with upper limb loss to replace some of the functionality of the upper limb. Given the wide range of tasks and movements the upper limbs can accomplish, replacing full functionality can be challenging. While advancements in prosthetic technologies have proven helpful in regaining some functions of the hand, adequately assessing the effectiveness of these devices is critical for further development. A wide range of self-report and performance-based clinical assessments are currently available to evaluate functional capabilities of prosthesis users. However, current clinical assessments are lacking in the ability to quantify how specific prosthetic technologies influence biomechanical movement strategies. Kinematic assessments using motion capture technology could fill this gap by quantifying upper body movement and compensatory strategies in prosthesis users. Selected tasks should mimic those from clinical assessments and challenge the function of prosthesis users through specific task requirements.

    Objectives: The overall goal of this thesis was to develop and validate a novel kinematic assessment tool using motion capture technology and two standardized functional tasks in order to characterize movement strategies of non-disabled individuals, and to illustrate the application of this tool in a prosthesis user population, namely transradial body-powered prosthesis users. The specific objectives were to: 1) investigate the consistency and between-session reliability of non-disabled hand movement for the two tasks; 2) quantify normative angular kinematics for the two tasks via peak angle, range of motion, and peak angular velocity measures and assess their between-session reliability; and 3) illustrate the use of the measure in a group of transradial body-powered prosthesis users, to identify key compensatory strategies by comparing upper body joint kinematics to normative values.

    Methods: A 12-camera Vicon motion capture system was used to collect three-dimensional marker trajectories at 120 Hz. Twenty non-disabled participants and five transradial body-powered prosthesis users had marker plates with reflective markers attached to upper body segments. Participants completed two standardized functional tasks. The Pasta Box task had participants move a box of pasta to shelves of different heights, and the Cup Transfer task had participants move filled compliant cups over a partition at table-top height. The tasks were divided into discrete movements based on hand velocity and hand trajectory. In non-disabled participants, hand function measures were extracted from three-dimensional hand motion, namely hand distance travelled, hand trajectory variability, peak hand velocity, percent-to-peak hand velocity, number of movement units, peak grip aperture, percent-to-peak grip aperture, and percent-to-peak hand deceleration. In both non-disabled and prosthesis user participants, joint kinematic measures were extracted from three-dimensional joint angles, namely peak angle, range of motion, and peak angular velocity. For all the above measures in the non-disabled data, consistency in task performance was assessed by calculating within-participant variability, and between-session reliability was assessed using the intra-class correlation coefficient. Following non-disabled participant data analysis, the upper body joints’ ranges of motion for the body-powered prosthesis users were compared to those of the non-disabled individuals to identify any compensatory movements employed by prosthesis users to complete the task.

    Results: The two standardized functional tasks elicited consistent kinematic strategies within a non-disabled population, with good between-session reliability. Cross-body movements in the Pasta Box task caused an earlier occurrence of hand velocity peaks, and movements requiring clearing an obstacle while transporting an object displayed double hand velocity peaks and longer deceleration phases. Both tasks required minimal trunk motion. Cross-body movements and reaches to objects further away required greater range of motion at the trunk and at the elbow joint. In prosthesis users, compensatory strategies were identified mainly at the trunk. While no significant shoulder compensations were observed in prosthesis users, some reduction in shoulder flexion/extension occurred, likely due to the restrictive nature of the harness required to operate a body-powered prosthesis.

    Discussion: This work successfully developed a novel kinematic assessment and validated its use in a non-disabled population by reporting on hand function and angular kinematic strategies for two standardized functional tasks. The use of this assessment was illustrated in a prosthesis user population, where the tasks challenged key areas of prosthesis use, identifying compensatory strategies at the trunk. This assessment has created a foundation for the quantitative assessment of prosthesis users of various prosthetic technologies and levels of amputation.

  • Subjects / Keywords
  • Graduation date
    Spring 2020
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
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