Conventional functional electrical stimulation (FES) therapy, if provided shortly after an
incomplete spinal cord injury, is able to help an individual to restore voluntary hand
function. This is thought to occur through the induction of neuroplasticity. However,
conventional FES therapy employs a push-button-based control scheme, which does not
fully require the recipient to generate volitional movements. The first study in this thesis
therefore sought to determine, in an early proof-of-concept test with able-bodied
participants, whether control strategies which are triggered by volitional activity
(including an electroencephalography-based brain-machine interface (BMI-FES) and an
electromyogram-based control scheme (EMG-FES)) might provide greater benefits to
hand function. The results offer relatively weak evidence to suggest that BMI-FES, and
especially EMG-FES, were able to induce greater neuroplasticity than conventional
treatments in the corticospinal tract leading to the hands, but that this did not
immediately translate to more functional improvements such as maximum grip force.
ii
The second study in this thesis focussed on spinal associative stimulation (SAS), which
involves paired stimulation pulses at both the head (via transcranial magnetic
stimulation), and the wrist (via peripheral nerve stimulation). The purpose of this, as with
the first study, was to induce neuroplasticity and upregulate the corticospinal tract
leading to the hands. While limited research has suggested that it is possible to produce
neuroplasticity through SAS, all such studies have provided stimulation at a fixed
frequency of 0.1 or 0.2 Hz. The present study therefore sought to compare the
effectiveness of a typical 0.1 Hz paradigm with a 1 Hz paradigm, and a paradigm which
provided stimulation in 5 Hz “bursts”. None of the paradigms were able to successfully
induce neuroplasticity in a consistent manner. The increased variability in this study as
compared to the previous one, despite the nearly identical assessment methodology,
suggests that responses to the SAS treatment may have been highly individual. This
serves to highlight a potential limitation of the treatment, which is that its effectiveness
may not be universal, but rather dependent on each specific recipient. This may be a
challenge faced by SAS should it continue to be tested as a novel therapy.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/65703 |
| Date | 13 August 2014 |
| Creators | McGie, Steven |
| Contributors | Popovic, Milos |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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