Summary: Researchers have developed a BCI that can decipher and communicate the thoughts of those with locked in syndrome.
Source: Wyss Center for Bio and Neuroengineering.
Completely locked-in participants report being ‘happy’.
A brain-computer interface that can decipher the thoughts of people who are unable to communicate could revolutionize the lives of those living with complete locked-in syndrome according to a new paper published in PLOS Biology. Counter to expectations, the participants in the study reported being “happy” despite their condition.
In the trial, people with complete locked-in syndrome, who were incapable of even moving their eyes to communicate, were able to respond “yes” or “no” via thought to spoken questions. A non-invasive brain-computer interface (BCI) detected their responses by measuring changes in blood oxygen levels in the brain.
The results overturn previous theories that people with complete locked-in syndrome lack the goal directed thinking necessary to use a brain computer interface and are therefore incapable of communication.
Extensive investigations were carried out in four people with ALS (amyotrophic lateral sclerosis) – a progressive motor neuron disease that leads to complete destruction of the part of the nervous system responsible for movement.
The researchers asked personal questions with known answers and open questions that needed “yes” or “no” answers including: “Your husband’s name is Joachim?” and “Are you happy?”. They found the questions elicited correct responses seven times out of ten.
Professor Niels Birbaumer, a neuroscientist at the Wyss Center for Bio and Neuroengineering in Geneva, Switzerland (who was formerly at University of Tübingen, Germany), senior author of the paper said: “The striking results overturn my own theory that people with complete locked-in syndrome are not capable of communication. We found that all four people we tested were able to answer the personal questions we asked them, using their thoughts alone. If we can replicate this study in more patients I believe we could restore useful communication in completely locked-in states for people with motor neuron diseases.”
The question “Are you happy?” resulted in a consistent “Yes” response from the four people, repeated over weeks of questioning.
Professor Birbaumer said: “We were initially surprised at the positive responses when we questioned the four completely locked-in participants about their quality of life. All four had accepted artificial ventilation in order to sustain their life when breathing became impossible so, in a sense, they had already chosen to live. What we observed was as long as they received satisfactory care at home, they found their quality of life acceptable. It is for this reason, if we could make this technique widely clinically available, it would have a huge impact on the day-to-day life of people with complete locked-in syndrome”.
In one case, a family requested that the researchers ask one of the participants whether he would agree for his daughter to marry her boyfriend ‘Mario’. The answer was “No” nine times out of ten.
Professor John Donoghue, Director of the Wyss Center, said: “Restoring communication for completely locked-in people is a crucial first step in the challenge to regain movement. The Wyss Center plans to build on the results of this study to develop clinically useful technology that will be available to people with paralysis resulting from ALS, stroke or spinal cord injury. The technology used in the study also has broader applications that we believe could be further developed to treat and monitor people with a wide range of neuro-disorders.”
People with preserved awareness and cognition but complete paralysis except for up and down eye movements and blinking are classified as having locked-in syndrome. If all eye movements are lost, the condition is referred to as complete locked-in syndrome.
The BCI technique in the study used near-infrared spectroscopy (NIRS) combined with electroencephalography (EEG) to measure blood oxygenation and electrical activity in the brain. While other BCIs have previously enabled some paralyzed patients to communicate, NIRS is so far the only successful approach to restore communication to people who have complete locked-in syndrome.
NeuroscienceNews would like to thank Jo Bowler for submitting this research news directly to us for inclusion.
Source: Jo Bowler – Wyss Center for Bio and Neuroengineering
Image Source: NeuroscienceNews.com image is credited to Wyss Center for Bio and Neuroengineering.
Original Research: Full open access research for “Brain–Computer Interface–Based Communication in the Completely Locked-In State” by Ujwal Chaudhary, Bin Xia, Stefano Silvoni, Leonardo G. Cohen, and Niels Birbaumer in PLOS Biology. Published online January 31 2017 doi:10.1371/journal.pbio.1002593
Brain–Computer Interface–Based Communication in the Completely Locked-In State
Despite partial success, communication has remained impossible for persons suffering from complete motor paralysis but intact cognitive and emotional processing, a state called complete locked-in state (CLIS). Based on a motor learning theoretical context and on the failure of neuroelectric brain–computer interface (BCI) communication attempts in CLIS, we here report BCI communication using functional near-infrared spectroscopy (fNIRS) and an implicit attentional processing procedure. Four patients suffering from advanced amyotrophic lateral sclerosis (ALS)—two of them in permanent CLIS and two entering the CLIS without reliable means of communication—learned to answer personal questions with known answers and open questions all requiring a “yes” or “no” thought using frontocentral oxygenation changes measured with fNIRS. Three patients completed more than 46 sessions spread over several weeks, and one patient (patient W) completed 20 sessions. Online fNIRS classification of personal questions with known answers and open questions using linear support vector machine (SVM) resulted in an above-chance-level correct response rate over 70%. Electroencephalographic oscillations and electrooculographic signals did not exceed the chance-level threshold for correct communication despite occasional differences between the physiological signals representing a “yes” or “no” response. However, electroencephalogram (EEG) changes in the theta-frequency band correlated with inferior communication performance, probably because of decreased vigilance and attention. If replicated with ALS patients in CLIS, these positive results could indicate the first step towards abolition of complete locked-in states, at least for ALS.
“Brain–Computer Interface–Based Communication in the Completely Locked-In State” by Ujwal Chaudhary, Bin Xia, Stefano Silvoni, Leonardo G. Cohen, and Niels Birbaumer in PLOS Biology. Published online January 31 2017 doi:10.1371/journal.pbio.1002593