Blood Oxygen Levels May Help Paralyzed ALS Patients Communicate, Researchers Say

Joana Fernandes, PhD avatar

by Joana Fernandes, PhD |

Share this article:

Share article via email

ALS patients with complete paralysis can communicate in a limited manner using a computer interface that detects their thoughts based on blood oxygen levels in the brain, according to a new study.

Researchers said the method helped these patients say they were happy despite their extreme condition.

The study, “Brain-Computer Interface-Based Communication In The Completely Locked-In State,” was published in the journal PLOS Biology.

As ALS progresses, patients lose the ability to walk, move their limbs, talk, swallow, even breathe. They eventually achieve a complete locked-in syndrome in which they can no longer communicate.

One method that allows patients to maintain the ability to communicate is called a brain-computer interface (BCI), a method based on an electroencephalogram (EEG).

Researchers used a noninvasive BCI with near-infrared spectroscopy and EEG to measure blood oxygen levels and the brain’s electrical activity in four patients with ALS and complete locked-in syndrome.

Patients had to think the answers “yes” or “no” to spoken questions, such as “Your husband’s name is Joachim?” or “Are you happy?” By measuring blood oxygens levels, researchers found that in 70% of the trials, patients gave correct responses to the questions.

ALS patients in a completely locked-in state cannot use existing BCIs because these systems depend on brain processes that are impaired in the late stages of ALS, but these results show that the method used in this study may help these patients to communicate.

“The striking results overturn my own theory that people with completely locked-in syndrome are not capable of communication,” Niels Birbaumer, senior author of the study, said in a news release. “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.”

When asked if they were happy, the four patients replied “yes” repeatedly over the length of the study.

“We were initially surprised at the positive responses when we questioned the four completely locked-in patients about their quality of life,” Birbaumer said. “All four had accepted artificial ventilation in order to sustain their life when breathing became impossible; thus, in a sense, they had already chosen to live. 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.”

During the study, one family asked the researchers to ask one of the participants whether he would approve of his daughter marrying her boyfriend. The patient replied “No” nine times out of ten.

“Restoring communication for completely locked-in patients is a crucial first step in the challenge to regain movement,” John Donoghue, director of the Wyss Center, a nonprofit neurotechnology research foundation in Switzerland.

“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.”