It is hard to imagine being completely paralyzed but fully conscious; able to see, hear, smell and sense pain, but unable to communicate with the world. That's what it means to be "locked in." And it was amazing to learn in the course of reporting for our story on Brain Computer Interface technology that a 2002 survey found that the mental health of people in this condition was not significantly lower than that of the general population. What was not surprising to learn is that what is paramount to everyone is finding a way to communicate, and that is precisely the hope for this exciting branch of neuroscience.
When we first met Scott Mackler, a neuroscientist, he was working at his lab at the University of Pennsylvania. Sitting in a small office he was typing an email, choosing each letter one by one. Scott wore an EEG cap and stared at a matrix of flashing letters on the screen in front of him. The electrodes on his scalp picked up the electrical pulses which emanate from the brain, called field potentials. These signals show a discernable pattern when the letter Scott is searching for lights up. It's painstakingly slow to watch but for someone diagnosed with Amyotrophic Lateral Sclerosis nine years ago - who can't talk, can't move and can't even breathe on his own - it's remarkable.
ALS destroys the voluntary nervous system, leaving a person's mental faculties perfectly intact but trapped in an inert and helpless body. Scott is now completely "locked in." It is a condition that was explored in a film last year by Julian Schnabel, "The Diving Bell and the Butterfly." The movie tells the true story of Jean-Dominique Bauby who suffered a massive brain stem stroke that left his entire body paralyzed save for his eyes and one eyelid. He learned to communicate through blinking in response to a list of letters and dictated a memoir of his experience.
At home, Scott Mackler communicates with his wife Lynn, their two sons Noah and Alexander, and his assistant Dana using a similar system they developed that relies on the one slight movement he has left in his eyes. Dividing the alphabet in three parts, they begin by asking "first", "second", "third". To signal yes, Scott looks up. If he chooses "first" then they begin "a, b, c, d, e, and f" reciting letters until he looks up again. It's amazing how quickly they now speak this language.
I found it difficult to communicate with Scott initially. When I spoke to him I felt self-conscious and it made me aware of how accustomed I am to looking for facial cues to determine how people are responding. But it soon became clear that despite his challenging circumstances, Scott has a wry sense of humor about everything, including himself. The PowerPoint presentation he put together for our visit included Robin Williams imitating Stephen Hawking and the Monty Python song, "always look on the bright side of life."
A few days later we went to interview Cathy Hutchinson, who lives at a nursing home outside Boston after a brain stem stroke 12 years ago left her "locked in." In her daily life Cathy uses what is called a letter board, which is a clear plastic board with the alphabet printed on it. Like Scott Mackler, she is able to move her eyes and she also has some facial expression left. Holding the board up between you, you can follow her eyes as she looks at a letter. When you think you know which letter she is looking at you call it out and if you've got the right one she signals by looking up. It is slow and cumbersome but you feel like you are having a conversation. Her son Brian and her daughter Holly were both there for our visit and she communicates with them using this board.
Cathy volunteered to be a participant in a clinical trial in which the Braingate system was implanted directly in her motor cortex. She is the only person in the world with this kind of implant and one can only imagine that it is exciting to be a part of this ground breaking study and to be able to control her environment in ways she otherwise never could. It turns out that the part of the brain that correlated with hand movements still works even after a person is paralyzed. It was one of the surprising things that was learned at the onset of the Braingate study. So when Cathy thinks about moving her hand in a particular direction the individual neurons in her brain let off a series of electrical impulses. The rate of those impulses correlates to a particular movement and almost like a kind of morse code it can be converted into a digital language of zeros and ones that a computer can analyze. Once a pattern has been established the computer essentially translates the signals her brain is trying to send to her body. This allows Cathy to move a cursor on a screen just by thinking about moving her hand, exactly as she would if she were controlling a computer mouse. With that control she has been able to do basic things like turn off the lights, control a wheelchair and change the channel on the television. Things we may take for granted but which Cathy says of are the utmost importance. She told us the first thing she would want to use the Braingate system for would be to simply control her own bed. At this point the Braingate system doesn't allow her to use the system outside the study and when the clinical trial is over Cathy will have to have the implant removed.
One piece of reporting that didn't make it into our story is that the team of scientists at Brown University is hard at work developing the next generation of implants. Arto Nurmikko, a professor of engineering at Brown University, has developed a fully implantable electrode array. In his lab he demonstrated for us how the new implant would pick up electrical signals from the motor cortex and send the information through a wireless system using infrared light to a computer. Eliminating the need for a port on the head would reduce the risk for infection and be a major step forward. Currently this is still in a prototype stage but the hope is for this implant to be in a clinical trial in the next 5 years.
Beyond the fascinating science, it was the people we met that made this story remarkable. People like Catherine Wolf, who was diagnosed with ALS in 1996. Catherine is a poet who uses the same EEG system Scott Mackler does to communicate. These are her words:
© 2005 Catherine Wolf
I refuse to die
I choose to defy
I will see
I refuse to die
I choose to defy
Eat chocolate every day
I refuse to die
I choose to survive
Written By Anya Bourg