Due to the progressive degeneration of motor neurons in the brain and spinal cord, patients with late-stage amyotrophic lateral sclerosis (ALS) often lose all muscle control, preventing them from being able to communicate with others. Now, researchers at The Wyss Center at Campus Biotech in Geneva, Switzerland, have found that a non-invasive brain-computer interface could facilitate communication for patients with ALS.
ALS patients who are completely paralyzed, but are still able to make small eye movements such as blinking, have few options when it comes to communicating. Once they have lost the ability to verbally communicate – a condition known as locked-in syndrome – these patients may rely upon devices that use finger and eye movements to converse with others.
Completely locked-in syndrome, on the other hand, occurs once the disease has progressed to the point where even eye muscle movements cease. In their study, the Weiss researchers worked with four such patients with completely locked-in syndrome, as well as two patients in the advanced stages of locked-in syndrome.
Using the brain-computer interface – which uses functional near infrared spectroscopy (fNIRS) – the ALS patients answered both personal questions and yes or no questions by only thinking of their answers. By measuring changes in blood oxygen levels, the brain-computer interface was able to detect the participants’ responses.
The long-held belief that patients with completely locked-in syndrome do not have the thinking ability necessary to operate a brain-computer interface was challenged by the results of the study. The patients showed a correct response rate of 70 percent to personal questions with known answers.
“The striking results overturn my own theory that people with completely locked-in syndrome are not capable of communication,” said Dr. Niels Birbaumer, senior research fellow at the Wyss Center, and senior author of the study. “We found that all four patients 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.”
Perhaps surprisingly, when the four patients with completely locked-in syndrome were asked the question, “Are you happy?” they consistently responded yes over the entirety of the study period. The study results were published in the journal, PLOS Biology.
“What we observed was that 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 could have a huge impact on the day-to-day life of people with completely locked-in syndrome,” said Birbaumer.