Objectives: The purpose of this study is to investigate attentional (internal vs. external) focus effects on persons with amputation to perform a defined compensatory movement to reduce the likelihood of a fall. An internal focus of attention directs a person's conscious attention to their body's movements, whereas an external focus of attention directs a person's conscious attention to the effects of their movements or specific features in the environment. Numerous experiments have investigated the effects of an internal and external focus of attention on motor performance and the findings are in favor of an external focus of attention. In our work, we propose a motor learning research experiment to evaluate attentional focus strategies on the rehabilitation outcomes of learning and adaptation to the new proprioceptive information for persons with a recent transtibial amputation.

Research Design and Methodology: For this pilot study, six participants with recent unilateral transtibial amputation will be recruited. Four participants will receive internal and external focus of attention training methods while the other two (control group) will receive standard prosthetic training instructions. The experiment will be conducted in three phases: Phase 1 -- Baseline Performance Test, Phase 2 -- Training sessions, and Phase 3 - Learning Test. The training will utilize a vibrotactile device designed to generate tactile sensations at the skin-socket interface simulating contact of the prosthesis with the environment. The sensation simulates a perturbation that signals a potential fall event. During the experiment the augmented sensory information will be introduced randomly while participants walk at a preferred pace on a level surface. Movement kinematics and kinetics of the body will be recorded for analyses using a motion capture system with force plates.

Finding: It is hypothesized that the external focus of attention condition will outperform the internal focus of attention condition when responding to perturbations. The external focus of attention condition will yield faster response time and show improved compensatory responses compared to the internal focus of attention group by producing a greater lateral displacement of the artificial limb relative to the line of progression. In addition, the external condition will demonstrate a greater step length and step height than the internal focus of attention condition when provided with a perturbation.

Clinical Significance: Current practices within the field of Physical Therapy reveal that there is little therapeutic intervention for fall prevention. Instructions are traditionally provided on how to reduce the risk of falling through preparation of a room or obstacle avoidance or on the proper way to fall to decrease injury. However, there are no protocols for providing a prosthetic user with compensatory strategies to avoid a fall after a perturbation occurs. The research findings can result in improved training protocols, which can improve rehabilitative outcome.

Impact/Significance: The growing number of prosthetic users presents a need for improved patient care and effective prosthetic training and rehabilitation methods. Complimentary to the mission of the VA, the results of this research could enhance the quality of patient care and further assist these patients toward becoming prosthetically rehabilitated.

Inclusion Criteria:

• Undergone amputation within the past year.
• Currently undergoing prosthetic training in Physical Therapy utilizing a prosthesis.
• Be within two weeks of completing prosthetic training in Physical Therapy.
• Ability to tolerate walking for a minimum of 100 yards over the course of a four hour time period with or without resting.
• No current skin breakdown on the residual limb.

Exclusion Criteria:

• Not cleared by Physical Therapy to use the prosthesis without contact precautions.
• Any medical or psychosocial condition that, in the opinion of the investigator, could jeopardize the subject's participation, and compliance with the study criteria