A cutting-edge brain-computer interface has successfully replicated communication with people who are living with “locked-in” syndrome, a state in which paralyzed patients are awake but unable to speak.
By measuring a person’s electrical activity in the brain, the brain-computer interface allowed patients to communicate in response to simple questions. For example, researchers asked patients personal questions that required a “yes” or “no” answer.
The patients, who were unable to move any parts of their bodies, even their eyes, because of their condition, were able to respond “via thought to spoken questions,” according to the study.
The brain-computer interface deciphered the patients’ responses by assessing fluctuating blood-oxygen levels in the brain. The results of the study, appearing in PLOS Biology, refute suggestions that people in a locked-in state are not able to understand language.
“The striking results overturn my own theory that people with complete locked-in syndrome are not capable of communication,” said study senior author Niels Birbaumer, who has studied locked-in patients for years.
“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,” added Birbaumer.
Giving Locked-In Patients a Voice
The researchers, reporting from the Wyss Center in Geneva, Switzerland, conducted an in-depth study of four patients with amyotrophic lateral sclerosis (ALS), a progressive, fatal neurological disease that attacks nerve cells responsible for muscle control. Commonly referred to as Lou Gehrig’s disease, ALS affects about four out of every 100,000 people worldwide.
One of the questions posed to the four patients – “Are you happy?” – elicited a “yes” response from each patient over repeated weeks of questioning.
“We were initially surprised at the positive responses when we questioned the four completely locked-in participants about their quality of life,” said Birbaumer.
“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,” he added.
The brain-computer interface uses near-infrared spectroscopy (NIRS) and electroencephalography (EEG) to assess a patient’s electrical activity and measure blood-oxygen levels. The authors report that the new technology is the first to allow patients with complete locked-in syndrome to communicate, and they believe it holds vast potential to improve the quality of life of patients suffering from neurological disorders.
“Restoring communication for completely locked-in people is a crucial first step in the challenge to regain movement,” said John Donoghue, director of the Wyss Center.
“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,” he added.