Dissertation
Transcutaneous spinal cord stimulation augments motor excitability and restores spinal inhibition and chloride homeostasis after spinal cord injury
Doctor of Philosophy (Ph.D.), Drexel University
Aug 2022
DOI:
https://doi.org/10.17918/00001360
Abstract
Spasticity is a complex and multidimensional disorder that impacts nearly 70% of individuals with spinal cord injury (SCI) and currently lacks adequate treatment options. This sensorimotor condition is burdensome as hyperexcitability of sensorimotor reflex pathways results in exacerbated reflex responses, co-contractions of antagonistic muscles, and involuntary muscle movements. Noninvasive transcutaneous spinal cord stimulation (tSCS) has become a popular tool in the human SCI research field, and recent applications have reported improvements in spasticity, suggesting the potential for this intervention to be used as an anti-spastic therapy after SCI. Yet, despite its popularity, the mechanisms of action and neuroplasticity induced by tSCS remain widely unexplored, particularly due to lacking animal model investigations with this intervention. Thus, the basis of this thesis is to use tSCS to target spasticity after SCI and elucidate the physiological improvements and neuroplasticity that can be achieved. In summary, we (1) successfully developed a clinically relevant rat model for tSCS, (2) showed that repeated treatment with tSCS in animals with an incomplete SCI decreased hyperreflexia while increasing H-reflex modulation, augmented motor output, and restored potassium-chloride co-transporter isoform 2 (KCC2) membrane expression in lumbar motoneurons, and (3) found that a stimulation protocol that alternates intensities between above and below motor threshold preferentially improved muscle co-contractions, restored spinal inhibition, and returned KCC2 membrane expression. Together, this thesis displays that an ideal paradigm of repeated tSCS can target and diminish spasticity after SCI and begins to highlight the underlying neuroplasticity contributing to the success of this intervention.
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Details
- Title
- Transcutaneous spinal cord stimulation augments motor excitability and restores spinal inhibition and chloride homeostasis after spinal cord injury
- Creators
- Dillon C. Malloy
- Contributors
- Marie-Pascale Côté (Advisor)Rodrigo A. España (Advisor)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xii, 147 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- College of Medicine; Neurology; Drexel University
- Other Identifier
- 991019104611204721