Despite the significant functional limitations imposed by upper limb loss, little research has focused on quantifying the functional success and satisfaction of prosthesis users. Most existing evidence comes from surveys, rather than experimental outcomes. Without a quantitative baseline, it is difficult to know where to focus attention for improvement in future prosthesis designs or to demonstrate whether new designs offer advantages over existing technologies. Thus, the goal of this dissertation was to quantify how functional outcomes and satisfaction relate to the type of prosthesis used.

The first aim was to determine if prosthesis type affects embodiment, or the extent to which prosthesis users perceived their prosthesis to be part of their body. We quantified embodiment for body-powered (BP) and myoelectric (MYO) prosthesis users based on a survey and two objective measurements of body schema and peripersonal space. Although BP users reported a stronger sense of agency over their prostheses in comparison to MYO users, other measures did not consistently differentiate experiences of embodiment based on prosthesis type. However, measurements of body schema varied depending on the cause of limb loss.

The second aim was to determine if prosthesis type impacts movement quality during activities of daily living. As an initial step for this aim, we quantified the reliability of movement quality metrics (three measures of smoothness and one measure of straightness) in healthy adults performing a variety of different tasks. Based on these findings, we then compared movement quality in BP and MYO prosthesis users during a subset of tasks (moving a can from a low shelf to a high shelf, placing a pill in a pillbox, and placing a pushpin in a bulletin board) using the metrics that had the highest reliability. All movements were slower when performed with MYO prostheses, except for the reaching phase of the pill task. Object manipulation movements were consistently less smooth when performed with MYO prostheses. However, differences in curvature of the reaching movements between the prosthesis types varied across tasks.

The third aim was to determine if prosthesis type affects kinematic compensations during activities of daily living. We quantified lateral lean, axial rotation, and flexion of the trunk during the same three activities of daily living. The range of motion was greater in all directions for BP prostheses during each task—except axial rotation and flexion during the pin task, which were greater for MYO prostheses.

The fourth aim was to explore the factors associated with interest in noninvasive (myoelectric) and invasive (targeted muscle reinnervation, peripheral nerve interfaces, cortical interfaces) interfaces for prosthesis control. An online survey collected opinions from 232 individuals with upper limb loss on the interfaces. Relationships between interest in the interfaces and demographics, limb loss characteristics, and prosthesis use history were defined using bivariate analysis and logistic regression. There was increased interest in the invasive interfaces among individuals who were younger, had unilateral limb loss, or had acquired limb loss.

Taken together, these aims suggest that BP prostheses may promote embodiment and smooth movement, while MYO prostheses may minimize compensatory movement. Although emerging prosthesis technologies requiring surgical intervention may not be accepted by all individuals with upper limb loss, functional outcomes with these technologies should be compared to outcomes with existing BP and MYO prostheses to demonstrate the relative merits of each design.