Patients With Locked-in Syndrome May Be Able to Communicate After All
A new use for brain-computer interfaces gives insight to life with ALS
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As ALS progresses, the neurons that control muscle movement begin failing, one after another. Patients lose the use of their arms and legs, and eventually, their breathing. Now they’re locked in, dependent on a medical ventilator. The last to go is the eyes, a condition called complete lock-in.
How do you know what someone is thinking, if you can’t communicate with him or her? For a long time, scientists thought that, at this stage, patients were incapable of directed thought. But a team of researchers at the Wyss Center for Bio and Neuroengineering, in Geneva, Switzerland, has new evidence that contradicts this, and a new way to get insight into what completely locked-in patients are thinking.
“The primary innovation is that this is the first paper, the first report which could describe completely locked in patients to communicate,” says Niels Birbaumer, who led the research.
The way they did this was to apply traditional means of non-invasive brain scanning in a new application. EEG, which reads brain waves, can record a person’s awareness and vigilance. Near-infrared spectroscopy, or NIRS, measures the oxygenation of the blood in a person’s brain, which a lock-in patient can learn to control—if they are aware and vigilant.
It works something like a polygraph. While wearing a NIRS apparatus (typically a neoprene helmet with dozens of optical sensors sticking out of it), a patient is asked hundreds of baseline yes/no questions with known answers—“Berlin is the capital of France?” or “Berlin is the capital of Germany?” Over the course of days, a computer compares the oxygenation of the blood in the frontal lobe until it sees a distinguishable difference between the true questions and the false questions.
“We always have a lie detection system in the sense that each question has a second question, which asks the contrary,” says Birbaumer. If the second, opposite question is also answered in the affirmative, the results are tossed. Additionally, if answers are not consistent, those answers are tossed too. “These are ways of validating it, but you have to face the fact that you can never know the truth 100 percent.”
Once the patient’s answers are correct 70 percent of the time, the researchers deemed that sufficient to attribute them as decisions, and began asking other questions: Are you comfortable? Do you feel pain? Do you approve of your daughter’s marriage to Mario?
Without alternative means to communicate, it’s difficult to confirm that answers are intentional. Birbaumer has largely relied on repetition and control questions, but his research raises the question of what exactly it means to communicate.
“What are these yes and no answers that the person is giving you? Is it truly reflecting communication as we think it? Are they formulating thoughts the way we’re thinking? You can’t really understand exactly what the state of their mind is,” says John Donoghue. Donoghue is a professor of neuroscience at Brown University and founding director of the Wyss Center, but had no role in Birbaumer’s research. Donoghue himself works with implanted electrodes, in an attempt to give lock-in patients control over cursors, robotic arms, or even their own arms.
“Perhaps because we’re now at a point where electronics and devices are better than they were a decade ago, we can actually look forward to the day when we can really help people who are paralyzed communicate, interact, take care of themselves, drink coffee when they want to, and then go on to do everything that we do,” says Donoghue.
Even just knowing the mental state of locked-in patients could have huge ramifications for the way we approach care for them. Birbaumer’s study featured just four patients, but each had chosen, while they still could, to continue to receive care and to stay alive. Using the new technique, Birbaumer asked each patient questions from the World Health Organization’s quality of life assessment, and received almost uniformly positive answers. All four people repeatedly responded “yes” to the question, “Are you happy?” But Birbaumer says only 5 percent of ALS patients choose to go on artificial respiration.
“The reason that people decide to die when they [have to] go on respiration is mainly caused by the negative attitude the environment and the family and the doctors have toward the disease and toward paralysis,” says Birbaumer. “The outside world are judging the quality of life terrible … doctors and the whole medical establishment and insurance companies and everybody reinforces that belief, and that’s why the people then die, which is a tragedy. This is an immense tragedy.”
Use of the technique among patients and their families could become widespread, if the operations are simplified. The technology itself isn’t particularly expensive, and Birbaumer gives the program that analyzes a patient’s responses out for free. Ideally, it will find its way into homes, enabling daily communication between locked-in patients and their loved ones.