Spatiotemporal Electrical Stimulation of Abnormal Brain Cavity Wall to Restore Post Stroke Motor Impairment in Rats

Cerebrovascular accident (stroke) is the second leading cause of chronic disability and death. New strokes affect 10.3 million people per year worldwide. The amount of stroke survivors is increasing, but many remain with severe post-traumatic symptoms. Hence, stroke is a major economic burden, with a cost of around 45 billion € in Europe in 2017 alone. Only 44% of this cost is due to the initial treatment, the remaining 56% is related to the chronic care setting (rehabilitation, nursing home, loss of productivity by the patient, etc.). Today, several treatments are available in the acute (< 24 hours) and subacute phase, but there is no proven clinical therapy yet for chronic (> 6 months) stroke patients. A stroke may cause a large amount of neurons to die, creating an abnormal brain cavity (aBC), often with an irregular shape. Surviving neurons near the aBC wall often show abnormal behavior, resulting in the patient’s chronic post-stroke problems. Recently, indications have been reported that such patients may benefit from neurostimulation at the aBC wall (similar in concept to deep brain stimulators) as a treatment in this chronic phase. Since state-of-the-art neural probes are excessively stiff to conform the irregular aBC wall, in this project, a novel class of neural recording and stimulation system will be developed and tested. They have flexible active electrode arrays, are inserted endoscopically into the aBC, and cover the aBC wall with a very high density of contacts, enabling the desired localized stimulation/recording. The active arrays will contain a chip, allowing for the selection of the bestplaced electrodes at any time, and for signal multiplexing, minimizing the wiring between the implanted arrays and the control electronics outside the brain. High selectivity provided by active chip enables us to perform spatiotemporal selective stimulation, which will be optimized during the course of this PhD. Finally, due to a dedicated novel encapsulation strategy, biocompatibility and hermeticity of the system are guaranteed, allowing in-vivo usage over a long period of time.