Biofeedback is a real-time training technique that involves measuring a physiological function and conveying information back to the patient, to help them learn to adjust their performance. Biofeedback is used successfully in many areas of neuromuscular rehabilitation and sports training. Lower limb amputees particularly present a need for augmented feedback. Following amputation the proprioceptive pathways required to regulate gait are impaired. During physiotherapy patients have a limited view of their body, and the physiotherapist may not be best physically placed to witness gait changes. Outside the clinic patients often adopt poor walking patterns, such as circumduction and abduction, which can lead to lower back pain and a reduced quality of life. This work focused on the development of a biofeedback training system to assist in the reduction of habitual circumduction and abduction gait patterns seen in trans-femoral amputees. Guided by a review of the literature, a training system was developed that uses electro-tactile sensory stimulation to provide feedback of the patient's thigh motion whilst they walk on a treadmill. A greater understanding of the psychophysical response to electro-tactile stimulation was required in order to present discernible information in a safe and comfortable manner. Thirteen healthy subjects were therefore recruited into a study that found thresholds of perception and discomfort to stimulation around the thigh. The study also found that subjects were able to discriminate the location of stationary stimuli and the speed and direction of moving stimuli whilst laying supine, flexing and extending the leg, and walking on a treadmill. By correctly identifying the numbered electrode locations they demonstrated an ability to perceive spatially coded information presented to the thigh using electrical stimulation. A camera-based motion capture system was incorporated into the completed biofeedback system, and software was written to capture kinematic data in real-time. To enable the calculation of feedback stimuli, a 3-dimensional biomechanical model was constructed and the patient's hip joint angles were compared to a joint angle reference database. Kinematic event detection made it possible to deliver the electro-tactile stimuli in relation to the users gait. Four amputees tested the biofeedback system and reported positively on the experience. The subjects did not walk with a circumduction gait, so it was not possible to assess the therapeutic effects of the system. However they were able to perceive and understand the feedback stimuli, relate the information to their movement, and in some cases make positive changes to their gait. Sensation threshold levels and the ability to discriminate stimuli were also found in the amputee group to be comparable with the non-amputees. This work has potential to become integrated into prosthetic components, and can be adapted for use with a broader range of patient groups with upper and lower limb movement disorders. The analysis software has potential to be further developed to provide real-time interpretation of gait patterns.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:581942 |
| Date | January 2013 |
| Creators | Webb, Graham |
| Contributors | Ewins, D. J. : Cirovic, S. : Ghoussayni, S. |
| Publisher | University of Surrey |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://epubs.surrey.ac.uk/795456/ |
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