This research study is being done to develop a novel brain-computer interface (BCI) technology that can enable severely paralyzed individuals to interact with the world through direct brain-control of a computer. This technology is named MindEx (for Mind Extender). It utilizes four implanted "chips" in the human brain from which investigators can record brain activity during subjects' thoughts and decode meaningful information from this activity to be used as control signals for a computer, a laptop, or a tablet. The use of four brain regions is a significant differentiating feature and scientific innovation of this study over much prior work in this space, that typically derived control signals from one, or sometimes two brain regions. The brain regions to be used here can allow the decode of multiple variables simultaneously, including not just moment-to-moment position, but also high-level goals, intentions, decisions, scene comprehension, and error-related signals involved in natural human behavior. The research is being done through a prospective, longitudinal, single-arm early feasibility study to examine the safety and effectiveness of using MindEx to provide the user an intuitive, efficient, and accurate ability to control multiple applications on a computer interface such as a word processor, a paint application, or to play simple video games. Such versatility could greatly improve the autonomy and quality of life of severely paralyzed individuals. Two subjects will be enrolled, each implanted with MindEx for a period of at least 53 weeks and up to 313 weeks. The study is expected to take at least one year and up to six years in total.
Paralysis resulting from cervical spinal cord injury (SCI), brainstem stroke (ischemic or hemorrhagic), or amyotrophic lateral sclerosis (ALS)
Provide informed consent
Understand and comply with instructions, if necessary, with the aid of a translator
Communicate via speech or other means
Presence of memory problems
Intellectual impairment
Psychotic illness or chronic psychiatric disorder, including major depression if untreated
Poor visual acuity
Single group
Mind Extender (MindEx)
DeviceNeuroPort Multi-Port Arrays allow for the local recording of cerebral cortex. The Mind Extender (MindEx) system is primarily composed of two NeuroPort Multi-Port Arrays. Each Multi-Port device consists of two arrays, each with 100 electrodes in a 10 x 10 configuration, with dimensions 4 mm x 4 mm x 1.5 mm (W x H x D), and a titanium percutaneous connector, 19 mm diameter at the base. Each MultiPort can have a total of 128 active channels (capable of transmitting neural signals to the percutaneous connector) across the two arrays. In our design, we will split active channels evenly between the two arrays resulting in 64 active channels per array. The four arrays of the two Multi-Port device will be implanted into prefrontal cortex, premotor cortex, primary motor cortex, and posterior parietal cortex.
Continuous trajectory decoding
A primary objective of this study is to evaluate the effectiveness of the system in providing users the ability to continuously move a cursor on a tablet/computer. The hypothesis is that trajectory readability from neural signals will be significantly greater than the level of chance. Standardized tests will be used to test this objective, and performance will be compared to the level of chance. One example of a standardized test to be used is the accuracy of continuous trajectory decoding measured by the radial-8 assessment task.
Incidence of intervention-related adverse events
Serious adverse events (SAE) will be evaluated against a 1% threshold level. We will use regular inspection of the subjects' scalps to assess for breakdown, discharge, or infection, and use history and physical exam to evaluate for new symptoms, and compare to baseline assessments.
Competency in computer/tablet control
An underlying hypothesis in this study is that the system will enable users the ability to control a computer/tablet interface by selecting icons. An underlying hypothesis in the study is that neural signals will enable decoding the chosen target at higher accuracy than the level of chance. Standardized tests will be used to test this objective, and performance will be compared to the level of chance. An example of a standardized test to be used is the brain-control for tablet test (BCTT) which grades the accuracy of target selection by mental fixation to the level of chance.
Efficacy of multiple brain regions for neural control over subsets of brain regions
An objective of this study is to determine whether the combination of neural signals from multiple brain regions in brain-computer interface control is more advantageous than from a subset of the brain regions being tested. The hypothesis is that because the four brain regions being implanted each encode different cognitive functions, their integration will be more useful to brain-computer interface control, than any subset of these regions. This objective will be tested by standardized tests (such as those mentioned for "Competency in computer/tablet control" and "Continuous trajectory decoding") in different groups of brain regions and reported for each, such as: 1. All four brain regions: prefrontal cortex (PFC), posterior parietal cortex (PPC), dorsal premotor cortex (PMd), primary motor cortex (M1) 2. PMd,PPC, and M1 3. PPC and M1 alone
Change in quality of life
The functional change in quality of life will be evaluated through a Quality-of-Life Inventory (QOLI) administered periodically throughout the study. This is a 32-item questionnaire with a score range from 1-77, with higher scores reflecting higher satisfaction.
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Nader Pouratian
Lead sponsor
University of Texas Southwestern Medical Center
Sponsor institution
