More than two million Americans are currently living with a full or partial limb loss, and an
additional 185,000 amputations occur each year. The majority of amputations occur in the
lower limbs. There are many potential causes for amputation, but the majority can be
attributed to vascular diseases, such as diabetes, traumatic injury, and cancer. For these
individuals, prosthetic devices play an important role in restoring mobility and enabling
them to participate in everyday activities. However, when learning to use these devices,
patients often alter their movement patterns to compensate for pain or discomfort, a
decreased ability to feel what their prosthetic limb is doing, and/or a fear of falling. By
changing their movement patterns, patients will tend to am their intact leg, which has been
shown to lead to long-term joint damage and chronic injury. For perspective, 75% of United
States veterans living with amputation are diagnosed with a subsequent disease affecting
their muscle, bone, and/or joint health. Therefore, therapy sessions, known as gait
retraining, are an integral part of teaching prosthesis users to walk in a safe and efficient
manner.
With recent advances in wearable technology, researchers and therapists have begun exploring
the use of biofeedback systems to assist with this retraining. In these systems, wearable
sensors are used to measure how the patient is moving in real-time, and can provide
information on how much time they spend on each leg and how much each joint moves during
walking. Biofeedback refers to the process of communicating the information from these
sensors back to the patients instruct them whether they need to change their movements.
Previous research has shown that these systems have excellent potential for helping patients
with physical disabilities improve their quality of motion. However, relatively little
research has explored how well individuals with above-knee leg amputations respond to
biofeedback during gait retraining. Importantly, the question of whether the new movement
patterns taught using biofeedback will persist after training has finished remains
unanswered.
Therefore, the primary objective of this research is to determine whether biofeedback is a
feasible tool for gait retraining with above-knee prosthesis (including a prosthetic knee,
ankle, and foot) users. To answer these questions, forty individuals currently using
above-knee prosthetic systems will undergo a single session of biofeedback training. Half of
these populations will be from the civilian population, and half will be military veterans.
During this training, the biofeedback system will apply short vibrations - similar to those
generated by cellphones - to their skin every time that the patient reaches the desired
degree of hip rotation during walking. Participants will be instructed to keep increasing
their hip motion until they feel a vibration on every step. Before training, they will be
instrumented with a wearable motion captures system, pressure sensors embedded in their
shoes, and a wearable heart rate monitor. Using these devices, researchers will measure the
participants' walking patterns without biofeedback determine their current ability. Once
training is complete, their walking patterns will be measured again, first while using the
biofeedback system, and then again fifteen minutes and thirty minutes after the biofeedback
system has been removed. The data measured during these tests will enable researchers to
calculate functional mobility scores that are used to evaluate the quality of a patient's
walking, and then compare how these scores change before, during, and after biofeedback
training.
The knowledge gained through this research constitutes a critical step towards identifying
optimal biofeedback strategies for maximizing patient mobility outcomes. The findings will be
essential for the development of gait retraining protocols designed to reduce the incidence
of chronic injury, and enable patients to achieve their full mobility potential. Building on
these results, the next research phase will be to incorporate biofeedback training into a
standard six-week gait retraining protocol to evaluate its long-term effectiveness as a
rehabilitation tool. Unlike traditional gait retraining, which requires patients to visit
clinics in-person for all sessions, the wearable, automated nature of biofeedback training
will allow patients to continue gait training from home. This ability will enable patients to
continue training activities between sessions, and ultimately may be able to substitute for
some in-person visits. This potential for remote therapy has exciting implications for
improved access to care for individuals living long distances from their rehabilitation
providers, or those suffering from social anxiety, as well as during global health pandemics
where in-person visits are difficult.