Item – Theses Canada

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OCLC number
1006926296
Link(s) to full text
LAC copy
LAC copy
Author
Dupont, Anne-Caroline,1968-
Title
Therapeutic electrical stimulation : reversal of disuse atrophy and clinical outcome measures.
Degree
Ph. D. -- Queen's University, 2001
Publisher
Ottawa : National Library of Canada = Bibliothèque nationale du Canada, [2001]
Description
2 microfiches
Notes
Includes bibliographical references.
Abstract
When volitional control of a muscle is lost, muscles atrophy. Electrical neuromuscular stimulation (NMS) has been developed to exercise paralysed muscles in order to prevent and reverse disuse muscle atrophy. The work presented here comprises three research projects aimed at understanding better the factors that influence disuse muscle atrophy and its reversal using NMS. We have used a tetrodotoxin (TTX)-paralysed rat model to investigate the effects of lengthening and shortening muscles on the degree of atrophy that follows. We have then evaluated the effects of NMS using four different stimulation paradigms delivered with a novel intramuscular stimulator, the BION. Finally, we have developed a method and protocol to measure atrophy and hypertrophy non-invasively in human muscles that are the subject of an ongoing clinical trial of BIONs for NMS. In a model of hindlimb paresis, we immobilised paralysed ankles in two positions, dorsiflexed and plantarflexed, eliminating the confounding factor of muscle activity present in previous experiments investigating the effects of muscle length on atrophy rates. Our results showed that the length at which a muscle is kept influences its rate of atrophy even in the complete absence of neuromuscular activity; lengthened muscles atrophy at slower rates than shortened muscles. In a subsequent study, we used four different NMS paradigms on paralysed rat muscles. The paradigms differed in stimulation frequency (2 or 10 pps) and duration of stimulation (2 or 10 hours/day for 7 days). Our results showed that the lower stimulation frequency was more effective at preventing atrophy than the higher frequency paradigms. This has important implications for understanding the trophic mechanisms involved in muscle maintenance and for choosing optimal parameters in rehabilitation programs using NMS. Finally, we showed that real-time ultrasound can be a precise and accurate method of measuring human deltoid and supraspinatus muscle thickness; however, a strict protocol must be followed to ensure reproducibility. Ultrasound is an imaging method of choice because it does not expose the patient to ionising radiation as computerised tomography does, nor is it contraindicated for patients with biomedical implants as is magnetic resonance imaging.
ISBN
0612560775
9780612560772