A wireless closed-loop implantable system for the real-time surveillance and modulation of central nervous system recovery following spinal cord injury
Abstract
For the twelve thousand annual cases of traumatic spinal cord injury (TSCI), there are limited treatment options. Basic supportive care is combined with a twenty-four hour regimen of high-dose methylprednisolone administered within eight hours post injury. This regimen is thought to help moderate further inflammatory damage, but the motor recovery results are marginal and the therapy highly debated. Discoveries in neural regeneration have shown that applied electrical fields (EFs) have the ability to enhance and guide new neuronal growth. Research into EF-stimulated growth and the implantable systems used to establish EFs has generated promising new medical therapies for TSCI. However, these discoveries have progressed without the quantification of stimulus amplitude, EF strength, or electrode-tissue interface stability. Quantitative analyses of EF strength and the electrode-tissue interface have relied on calculated models and in vivo studies using large-scale, non-implantable bio-instrumentation, respectively. To better realize the potential for electrically-stimulated CNS repair, we present a novel implantable, wirelessly-programmable prosthesis with injury-site EF surveillance, multi-waveform stimulation, and electrochemical impedance spectroscopy. Interface impedance measures the in vivo response to electrical stimulation over time. Wireless data transfer to and from an external system and a customized graphical user interface (GUI) add to patient mobility and complete the system loop. We have conducted in vitro and in vivo studies to validate system accuracy and biocompatibility. Efficacy differences between traditional oscillating direct current (dc) and alternating current (ac) stimulation were evaluated based on their quantified effect on functional and anatomical recovery in a TSCI rat model.
Degree
Ph.D.
Advisors
Irazoqui, Purdue University.
Subject Area
Neurosciences|Biomedical engineering
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