Original Research ARTICLE
Sensorimotor ECoG signal features for BCI control: A comparison between people with Locked-In Syndrome and able-bodied controls
- 1UMC Utrecht Brain Center, Netherlands
- 2University of Oxford, United Kingdom
- 3UMC Utrecht Brain Center, Neurosurgery and Neurology, Division of Neuroscience, Utrecht University, Netherlands
The sensorimotor cortex is a frequently targeted brain area for the development of Brain-Computer Interfaces (BCIs) for communication in people with severe paralysis and communication problems (locked-in syndrome; LIS). It is widely acknowledged that this area displays an increase in high-frequency band (HFB) power and a decrease in the power of the low frequency band (LFB) during movement of, for example, the hand. Upon termination of hand movement, activity in the LFB band typically shows a short increase (rebound). The ability to modulate the neural signal in the sensorimotor cortex by imagining or attempting to move is crucial for the implementation of sensorimotor BCI in people who are unable to execute movements. This may not always be self-evident, since the most common causes of LIS, amyotrophic lateral sclerosis (ALS) and brain stem stroke, are associated with significant damage to the brain, potentially affecting the generation of baseline neural activity in the sensorimotor cortex and the modulation thereof by imagined or attempted hand movement. In the Utrecht NeuroProsthesis (UNP) study, a participant with LIS caused by ALS and a participant with LIS due to brain stem stroke were implanted with a fully implantable BCI, including subdural electrocorticography (ECoG) electrodes over the sensorimotor area, with the purpose of achieving ECoG-BCI-based communication. We noted differences between these participants in the spectral power changes generated by attempted movement of the hand. To better understand the nature and origin of these differences, we compared the baseline spectral features and task-induced modulation of the neural signal of the LIS participants, with those of a group of able-bodied people with epilepsy who received a subchronic implant with ECoG electrodes for diagnostic purposes. Our data show that baseline LFB oscillatory components and changes generated in the LFB power of the sensorimotor cortex by (attempted) hand movement differ between participants, despite consistent HFB responses in this area. We conclude that the etiology of LIS may have significant effects on the LFB spectral components in the sensorimotor cortex, which is relevant for the development of communication-BCIs for this population.
Keywords: Brain-computer interface, Implant, sensorimotor cortex, Amyotrophic Lateral Sclerosis, Brain stem stroke, electrocorticography, High-frequency band, Low-frequency band
Received: 28 Feb 2019;
Accepted: 20 Sep 2019.
Copyright: © 2019 Freudenburg, Branco, Leinders, Vijgh, Pels, Denison, Berg, Miller, Aarnoutse, Ramsey and Vansteensel. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Prof. Nick F. Ramsey, Utrecht University, UMC Utrecht Brain Center, Neurosurgery and Neurology, Division of Neuroscience, Utrecht, 3584CX, Netherlands, email@example.com