The 38-year-old man had been in a "minimally conscious state" for six years after suffering a severe traumatic brain injury in an assault. After getting deep brain stimulation, he is now able to talk and eat on his own. His family has requested that his name not be released.
A minimally conscious state is different from a coma or a persistent vegetative state. Patients in a minimally conscious state occasionally show signs of arousal and organized behavior, but they have a "profound deficit in consciousness," states an editorial published in Nature.
Despite rehabilitation therapy, the man was nonverbal and couldn't swallow or communicate reliably.
"He infrequently mouthed single words when prompted but could not communicate yes/no responses reliably," write the researchers, who included Nicholas Schiff, MD, of New York's Weill Cornell Medical College.
But the man's brain scans showed that while he had severe brain damage, some of the networks within his brain were still intact.
Based on those brain scans, Schiff's team asked the man's family to let the man try deep brain stimulation.
Patient Improves With Deep Brain Stimulation
The doctors surgically implanted electrodes in the man's brain, targeting a brain area called the thalamus. Two days after surgery, the doctors turned the electrodes on as an initial test of deep brain stimulation.
When they did that, the man was able to keep his eyes open longer than before the surgery, and he was able to turn his head when someone spoke.
Over the next six months, the doctors gradually gave the man deep brain stimulation. He gained the ability to chew and swallow food and to talk more, even occasionally saying sentences up to six words long.
The man's improvements didn't disappear on days when he didn't get deep brain stimulation, and his ongoing rehabilitation therapy didn't appear to explain his progress, note the researchers.
Schiff and colleagues caution that other patients with severe traumatic brain injuries may not respond the same way to deep brain stimulation. They call for further studies on deep brain stimulation for patients with severe traumatic brain injury.
Patient's Mother Speaks
In a Weill Cornell Medical College news release, the patient's mother states, "My son, as well as the entire family, had little hope of further recovery. If it were not for the deep brain stimulation surgery and rehabilitation, we would be no further along than we were in 1999. Now my son can eat, express himself, and let us know if he is in pain. He enjoys a quality of life we never thought possible."
The results "raise hope," but "not all patients with disorders of consciousness will benefit from thalamic stimulation," states the editorial in Nature.
"Neuroscience is beginning to stitch together the neurologist's and the philosopher's ideas of consciousness. It is wonderful to see the fruits of this research help one patient. We hope that further studies will advance our knowledge and help more patients,' write the editorialists.
They included Michael Shadlen, MD, PhD, a professor of physiology and biophysics at the University of Washington in Seattle.