A man who spent 6 years in a minimally conscious state regained the ability to talk, eat, and move after doctors implanted electrodes deep in his brain.
"The improvements were significant, particularly the communication, because it allowed him to reengage his world," says Nicholas Schiff, a neuroscientist at Weill Cornell Medical College in New York City.
"We're essentially jump-starting the brain," says Ali Rezai of the Cleveland Clinic.
Before the surgery, the man, who suffered brain damage during an assault, was fed via tubes and showed almost no awareness. He sometimes moved his eyes and thumbs in response to simple, yes-no questions, but the pattern "was very inconsistent," says Schiff.
After receiving the pacemakerlike device, called a deep-brain stimulator, the man can chew and swallow, occasionally string together sentences, and move his arms and legs. He can demonstrate how to brush his teeth and drink from a cup, although years of immobility have atrophied his muscles, making it impossible for him to complete such actions.
Although the patient is still living in a hospital and is a long way from leading a normal life, the procedure offers hope to other patients in minimally conscious states, says neurosurgeon Rezai.
In a 10-hour operation, Rezai implanted two electrodes in the man's thalamus, a bifurcated, walnut-shaped structure in the middle of the brain. The thalamus serves as the brain's "grand central station," says Rezai, as it relays signals from sensory organs and muscles to the cortex above.
While theory suggested that activating the thalamus would increase overall brain arousal, the research team didn't know whether the treatment would help the patient.
Immediately after surgery, with the deep-brain stimulator sending signals into his thalamus, the man responded to voices and opened his eyes. After determining the device's optimal settings, the team started a 6-month period during which the stimulator was turned on intermittently to allow evaluation of the man's response. Physicians and therapists observing the man didn't know whether the device was on or off. [To see an animated clip showing how deep brain stimulation works, click here. (17 MB .MOV file. Broadband connection strongly reccomended.)]
"We went through pains to be able to say that [the improvements] were statistically linked to the brain stimulation," says Schiff, coauthor of a report describing the case in the Aug. 2 Nature.
Schiff, Rezai, and their colleagues received a special exemption from the Food and Drug Administration to perform the surgery. The team plans to enroll 11 more minimally conscious patients in the study.
"It's very important people realize this patient was not in a coma—he wasn't woken from a coma," says Michael Shandlen, a neurologist at the University of Washington Medical School in Seattle. Patients in comas and in persistent vegetative states have more-severe brain damage that would preclude the improvements seen in the study patient, he says.
Deep-brain stimulation is sometimes applied, in different parts of the brain, to patients with Parkinson's disease, intractable obsessive-compulsive disorder, or depression. Rezai estimates that some 40,000 people worldwide have the devices.
c/o Molly Johnson
9500 Euclid Avenue
Cleveland, OH 44195
Department of Neurology and Neuroscience
Weill Cornell Medical College
New York, NY 10021
Brownlee, C. 2005. Inner-brain electrode may curb depression. Science News 167(March 12):174. Available to subscribers at [Go to].
Seppa, N. 2006. Head to head: Brain implants are better for Parkinson's patients. Science News 170 (Sept. 2): 149. Available to subscribers at [Go to].
To see an animated clip showing how deep brain stimulation works, click here. (17 MB .MOV file. Broadband connection strongly reccomended.)
A version of this article written for younger readers is available at Science News for Kids.