UC Irvine

This dissertation seeks to develop novel neurorehabilitative therapies and neuroprostheses for restorative treatments in stroke and spinal cord injury (SCI) individuals. Since standard physiotherapies and substitutive solutions only provide a limited degree of restoration of the lost motor behavior in these individuals, novel brain-computer interfaces (BCI) have been sought. To develop BCI systems for stroke and SCI individuals, a high-performance electroencephalogram (EEG) based BCI system was developed and tested under several conditions. This system utilized data-driven decoding methodologies to obtain real-time control of several external devices. The external devices that were integrated and tested with this BCI system include a hand orthosis for stroke individuals with hand weakness, a noninvasive functional electrical stimulation (FES) system for the treatment of post-stroke foot drop, a virtual reality training environment to assess attempted or kinesthetic motor imagery of walking control strategies, a robotic gait orthosis mounted on a treadmill for ambulation training after SCI, and a noninvasive FES device for overground walking for those with paraplegia due to SCI. The BCI systems directed towards the treatment of stroke individuals focused on elementary motor behaviors common in chronic stroke individuals: foot drop and hand weakness (i.e. grasping and extension of the hand). On the other hand, the BCI systems for SCI individuals focused on ambulation after paraplegia. Finally, all systems were tested in both able-bodied individuals and those with stroke or SCI to assess the performance, safety, and applicability of these devices.

All BCI systems allowed individuals to control the external devices purposefully in real time. Furthermore, the BCI driven neurorehabilitative therapies and neuroprostheses presented here allowed for stroke and SCI individuals to obtain real-time control of the desired motor behavior using intuitive control strategies after only minimal training, and individuals were able to maintain this high level of control after several days to months. This provides preliminary evidence that neurorehabilitative therapies and implantable neuroprostheses in stroke and SCI individuals are feasible. If future studies are successful, these systems may provide noninvasive training platforms for implantable neuroprostheses or noninvasive neurorehabilitative therapies for stroke and SCI individuals, thus becoming novel restorative treatments.