Investigation on the Cortical Communication System

Overview

The goal of this clinical trial is to demonstrate communication through a brain implant in people in locked-in state, i.e. people with severe paralysis and communication problems. The main questions it aims to answer are efficient and stable control of Brain-Computer interface (BCI) functions for communication with attempted hand movements and operation of a keyword-based speech BCI. Participants will be implanted with four electrode grids, with in total 128 electrodes, on the surface of the brain and a connector on the skull. Participation includes visits of researchers for recording and training at home, 2-3 times per week for one year. Extension of participation after one year is possible. If successful, the participant will be able to use the BCI at home independently, without the presence of a researcher.

Locked-In Syndrome (LIS) is a neurological condition in which communication is impossible, or profoundly impaired, due to loss of speech and other motor functions, while cognition is intact. The most distressing aspect of LIS is the inability to initiate and sustain communication. Existing assistive technologies (ATs) fall short of a remedy. An effective brain-computer interface (BCI) for communication would dramatically improve quality of life for people with LIS. Electrocorticography (ECoG) with non-penetrating subdural electrodes is a promising implantable approach for BCI. In this study, the "CortiCom system" (which stands for Cortical Communication) wil be used. This system combines an implantable assembly, consisting of four small high-density (HD) ECoG grids on the hand and speech areas of the motor cortex, totalling 128-channels, and a transcutaneous pedestal connector, with an external data acquisition system. With the CortiCom system the overall hypothesis will be tested that broader and more densely spaced ECoG electrodes can better tap into the spatial detail of the organization of the sensorimotor cortex in order to expand BCI function and restore meaningful communication in LIS. Specifically, the CortiCom system will substantially increase the number and density of electrodes recording from the brain to determine whether more sophisticated control and communication can be achieved with more comprehensive and detailed spatial sampling of representations for movements of the hand/arm and of speech articulators. Clinically meaningful outcomes for people with LIS include rapid reestablishment, and stable maintenance of communication, at minimum consisting of a caregiver call-button and menu selections. Objective: Primary Objective 1: Demonstrate efficient and stable control of essential BCI functions (initiate BCI, call caregiver, and menu selections). Primary Objective 2: Demonstrate efficient and stable operation of a keyword-based speech BCI. Intervention: Participants will be implanted with an assembly consisting of HD-ECoG electrode grids over the sensorimotor cortex and a transcutaneous pedestal connector. The assembly will be connected with an external data acquisition system during recordings. During recordings, feedback about the neural signals is given via a visual display and participants are trained to employ the neural signals for fast brain-based communication. Upon adequate performance, participants can independently (i.e., without researcher involvement) train with and use the system at home for validation of performance and usability. After implantation, participation has a duration of 1 year, with a possibility of extension.