A Brain-Computer Interface Successfully Interpreted Responses from Patients with Locked-in Syndrome

Image Courtesy: Wyss Center
Image Courtesy: Wyss Center

A recent experiment revealed how a brain-computer interface succeeded in interpreting brain waves of patients suffering from locked-in syndrome, translating them into more understandable responses.

 Locked-in syndrome is a rare condition wherein a person is unable to move all their limbs, can’t communicate through speaking, and has no way of producing facial expressions. Movements such as swallowing and even breathing are also impossible for people with this condition.

However, the affected person can still see, hear, and comprehend everything that’s happening around them. They still possess normal reasoning and cognitive abilities before they got the condition but the only way they can respond to anything is through eye movements.

One possible cause of locked-in syndrome is brainstem hemorrhage due to possible trauma, infection, tumor growth, loss of myelin or nerve insulations, and severe nerve inflammations. Disorders such as ALS (amyotrophic lateral sclerosis), also known as Lou Gehrig’s disease, can also cause this syndrome.

A person with locked-in syndrome is literally trapped in a body that’s unable to communicate and translate their thoughts into tangible and more comprehensible gestures.

This recent technological development in the brain-computer interface may have the solution to circumvent the effects of this syndrome.

The brain-computer interface harnesses the capabilities of NIRS (near infrared spectroscopy) and EEG (electroencephalography) to measure the changes in the oxygen levels in the blood and the electrical pulses occurring in the brain. The NIRS is an imaging technique that utilizes low-energy radiation to assess changes in oxygen absorption of brain tissues which is usually triggered by neural activity.

This device was used in an experiment that involved four patients with locked-in syndrome caused by ALS. During the experiment, the patients were asked a series of very simple questions answerable only by yes or no.

Each time the patients thought of a response to a question, their brain activity is read by the NIRS/EEG interface and translates them to a definitive yes and no. The interface was able to clearly read 70% of their responses.

The researchers also asked the patients if they’re happy and have accepted their current condition. The team was surprised when all the patients answered “yes” to this question. This means they have a strong will to live and they just need help to restore their means of communication.

There have been other brain-computer interfaces developed years ago, but they were used to interpret brain waves of paralyzed patients. This NIRS/EEG system is currently the only successful approach used to interpret brain waves of patients with locked-in syndrome.

The researchers at the Wyss Center, who conducted the said experiment, plans to continue the developing this technology to create a useful device that can restore communication in people suffering from ALS, spinal injuries, and locked-in syndrome.