The overall goal of this research project is to investigate the effectiveness and the science of peer-based prosthetic skill training in individuals with leg amputation. Our belief is that amputee learners will show improved skill learning when observing demonstrations from other amputees, as opposed to observing nonamputee models. The investigators will accomplish the objective by answering the following two questions:

Question 1: Does peer-based observation training works better for learning motor tasks for individuals with lower limb amputation (LLA)?

Question 2: Are there differences in visual focus, behavior, and brain activation patterns when observing motor task demonstrations from amputee peers vs. non-amputees?

Participants of this study will be asked to learn a balance and a fall recovery task by observing video demonstrations by amputee peers vs. non-amputees. The investigators will compare which setting produce better learning.

Objective/Hypothesis: The overall objective of this project is to investigate the clinical scientific bases of peer observation sensori-motor skill training in individuals with lower limb amputation. The general hypothesis is that participants observing models who share the same levels of amputation with them (i.e. amputee peers) will exhibit traits of enhanced motor learning when compared to observing non-amputee models. Knowledge gained from this study will directly benefit the development of more effective rehabilitation protocols and has the potential to fundamentally transform the clinical practice of post-amputation rehabilitation.

Aim 1: Determine the effects of peer-based observation training on sensori-motor performance and learning in individuals with LLA. During a 2-week training period, the investigators will assess the differences in task performance and learning outcomes between participants who are instructed to learn to perform the tasks (i.e. balance and reactive fall arrest) by observing video demonstrations from amputee peers vs. non-amputees (n=20).

Aim 2: Examine the differences in visual focus, behavioral psychometrics, and brain activation patterns during and after observing motor task demonstrations from amputee peers vs. non-amputees. The investigators will compare the differences in visual focus time, task-specific self-efficacy, adopted mindset, and event-related brain activation patterns between the two conditions where participants learn to perform the motor tasks demonstrated by amputee peers vs. non-amputees.

Study Design: This research will use a cross-over design with a washout period to expose the participants to the two conditions in random order. In Aim 1, participants with unilateral LLA will be instructed to watch video demonstration of balance and fall recovery tasks performed by either an amputee peer or non-amputee with the intention of learning to perform the task. The subsequent 2-week training will consist of 60 practice trials for each task (over at least 3 sessions).

Participant's task performance (measured by time-in-balance during the balance task, and peak trunk flexion angle and rate of successful fall arrest during the fall recovery task) will be tracked before, throughout, and after (retention) training. To accomplish Aim 2, the investigators will evaluate and quantitatively measure the participant's visual focus (using eye tracking technology), psychometric traits (self-efficacy, motivation, and growth mindset), and brain activation patterns (assessed by electroencephalography, EEG) during the video observation and the corresponding training period.

Inclusion Criteria:

• 1) have unilateral lower limb amputation,
• 2) age >18 years,
• 3) are properly fitted with a walking prosthesis and use it regularly with at least moderate proficiency (K-2 level or above, further defined as scoring greater than 50 percentile on the Prosthetic Limb Users Survey of Mobility),
• 4) able to stand for at least 5 minutes without using an assistive device or experiencing excessive fatigue,
• 5) willing to travel to UNLV 6 times for training and testing.

Exclusion Criteria:

• 1) have other concurrent central nervous system diseases that influence motor function and balance,
• 2) have leg/foot ulcer or other conditions that cause pain during weight-bearing,
• 3) have cardiovascular, respiratory or other critical health conditions that preclude moderate physical activity.

There is currently not a plan to share participant data with other researchers.

Participants were randomized to experience one of the two conditions (amputee peers vs. non-amputees) demonstrating how to perform motor tasks. Participants were masked to the study hypothesis and the existence of the other group.