BACKGROUND: There are over 2 million people in the U.S. with some level of functional LIS. (Source: www.ohsu.edu/xd/research) Locked-In Syndrome is a rare neurological disorder characterized by paralysis of voluntary muscles in all parts of the body except for the muscles that control eye movement. The disease will leave the person completely paralyzed and mute. Communication is possible through blinking of the eyes. Patients are able to reason and are conscious; they just cannot move or speak. It could be a result from traumatic brain injury, diseases that destroy the myelin sheath surrounding nerve cells, diseases of the circulatory system, or medication overdose. There are three classifications of Locked-In Syndrome: complete LIS (quadriplegia), classic LIS (preserved vertical eye movement), and Incomplete LIS (recovery of some voluntary movements). (Source: www.ninds.nih.gov)
CAUSES: Locked-In Syndrome is most commonly caused by any condition that affects an area of the brain called the ventral pons. This part of the brain is where all of the nerve tracts that are responsible for voluntary movement pass through. The area of the brain that is responsible for consciousness is preserved above the ventral pons; therefore, allowing the person to be able to think. Diagnosis for a conscious individual with no muscle functioning means they respond to questions by blinking. Doctors will diagnose further by CT or MRI scans to reveal if there is a presence of stroke or aneurysm that could have caused the condition. (Source: www.ninds.nih.gov)
TREATMENT: Unfortunately, there is no cure or a standard treatment plan. A therapy called functional neuromuscular stimulation, which uses electrodes to stimulate muscle reflexes, might help to activate paralyzed muscles. There are also several devices to help with communication. The most important goal of rehabilitation is finding devices to assist the patient with communicating. (Source: www.ninds.nih.gov)
NEW TECHNOLOGY: A new device called noninvasive brain-computer interface (BCI) can allow people who are locked-in to communicate by operating a computer cursor. This type of technology was invented originally to be assistive technology and now it can be used for controlling video games, automating sailboats, robotics, and military tasks. Early studies of the BCI involved implantable sensors. Now the new BCI system can detect the brain’s activities through the scalp, from the surface of the brain, and then it can be processed by a computer to extract certain patterns. Patterns are then translated into commands for a device. Technology substitutes for the loss of typical neuromuscular outputs so that people can interact with their environments through brain signals rather than through muscle. (Source: www.ohsu.edu/xd/research)
Aimee R. Mooney, M.S.CCC-SLP/L, Speech and Language Pathologist, Specialist in Communication Support Augmentative Communication at the Oregon Health & Science University, Brain Institute, for people with severe physical and language disabilities talks about a brain computer interface that is helping patients with locked-in-syndrome.
So how long have you been working with Greg?
Ms. Mooney: I have been working with Greg for about three years. Greg has been part of the project for five years.
When you met Greg, what was he like when he first started?
Ms. Mooney: Greg has always had strong opinions and he’s got a great sense of humor. Now to the naked eye that might be hard to interpret because Greg has virtually no facial movement and no facial expression. So I’ve come to learn this through our many interactions. I learned about his communication from his caregivers and through our e-mails together.
How can you tell?
Ms. Mooney: How can I tell? He’s hilarious when he sends me e-mails. There’s a joke in every one, he teases, and he’s really fun.
How important is it that he has a way to communicate?
Ms. Mooney: It’s important for each of us. It’s essential to be able to communicate, not only your basic wants and needs, but pain and discomfort. Then there’s emotion and social closeness. I think communication is essential to all human relationships.
But you see on the other side patients with locked-in-syndrome who just don’t have the desire to want to get to the level that Greg is at.
Dr. Mooney: True. So, as you might imagine being locked in could cause severe depression and we do see people that have given up. Typically those who have given up who haven’t been given the opportunity to try and learn to communicate.
I was trying to follow him, but it seems exhausting for everyone?
Ms. Mooney: I think it seems that way initially but once you do it, it becomes second nature.
So you’re trying to eliminate that so you would not need to communicate that way.
Ms. Mooney: That’s right. So the very title of that form of communication is called partner dependent. As with all rehabilitation, we’re trying to make people as independent as they can be. So we would like to bypass having somebody else have to be in the room for you to communicate and have you to be able to use a technology where your brain wave is the way that you communicate or changes in your brain wave is the way that you communicate.
So how does that work?
Ms. Mooney: We’re using a noninvasive brain computer interface, BCI. What happens is the computer detects changes in your P300, which is one of your brain waves, and that change in the P300 wave is noted basically as a mouse click. A person utilizing the system will have on an electrode cap that is picking up changes or monitoring brain signals. We have something called RSVP, which is rapid serial visual presentation; those are letters that are flashing on a computer screen. So these letters are flashing at two hundred milliseconds. So let’s say you wanted to spell the word dog, when your brain sees the letter D in that series of letter your P300 spikes. The electrode cap sends that message to the program in the computer and it chooses D for you. You then see the next series of letters, as they go you see the O, there’s no movement in your entire body but again your P300 changes in response to seeing that O. The computer then picks up that and selects O for you. So in that way people can spell on a computer with having no movement.
Does every person with locked-in syndrome have that ability to change their brain wave?
Ms. Mooney: Yes, every human being has a P300 that is responsive to novel stimuli. People’s P300s may change as they age, and there are medications that affect your P300. Of course being fatigued affects your P300. There are factors that contribute to a less precise P300 change, but for the most part we think we can get an accurate P300 response in most patients.
Right now it’s a little cumbersome because you have to have the cap on and all the electrodes, where is this technology going in the future?