After a savage beating left him with severe brain injuries, a 31-year-old man spent six years in a twilight state. Then, a gentle current of electricity delivered by an implanted deep-brain stimulator (DBS) brought him back to life.
His success, described in the journal Nature in August, offers hope that some of the hundreds of thousands of people who languish on the margins of consciousness may also reawaken. It also implies that their brains may be more active than we realize, says the team that performed the treatment, which includes neurologist Nicholas Schiff of Weill Cornell Medical College in New York, neurosurgeon Ali Rezai of the Cleveland Clinic, and neuropsychologist Joseph Giacino of the JFK Johnson Rehabilitation Institute and the New Jersey Neuroscience Institute.
The patient, whose identity is withheld at his family’s request, had been clinging to life in a minimally conscious state (MCS)—a neurological limbo in which a person may intermittently be aware of his surroundings and occasionally respond to simple commands. From time to time, he would open his eyes, follow a command, and in rare instances, mouth a word, but that was about it. His mother visited his bedside daily, but there seemed little left of her son. “Each time I would visit him in the nursing home, on my way home I’d cry,” she said at a press conference.
Several critical factors led the team to hope he might benefit from DBS, including the fact that sometimes he did respond and an imaging study showed that language-processing regions of his brain activated in response to spoken words. More than 30,000 people have DBS implants, most of them having Parkinson’s disease or similar disorders. It has been used less frequently in those with traumatic brain injury and never before in this part of the brain. The implants work something like pacemakers for the brain, correcting or compensating for dysfunctional activity.
In this case, in a 10-hour-long neurosurgery, two small holes were drilled in the man’s skull, and two electrodes were placed in his central thalamus in a region that is thought to influence overall arousal levels and that connects to other regions relating to movement and motivation. The area also plays a role in speech, alertness, and focused attention. The electrodes were then calibrated to deliver the most effective stimulation.
“We immediately saw some changes, literally within the first day,” says Giacino. “The first and most striking was that he regained eye opening and was visually alert.” He also watched people moving and turned toward whoever was speaking. The team tested his alertness and responsiveness with the stimulator switched on and off and could see that it made a difference.
Over a period of months, with regular doses of electric stimulation, they began to see “clear-cut changes,” Giacino says. Now the patient can chew and swallow food and is relearning to brush his teeth. He can speak short sentences. “He can cry, and he can laugh,” his mother said, struggling to hold back tears. “He can say, ‘I love you, Mommy.’?” He is still extremely disabled, but in a fundamental way, he is back.
It’s almost as if his brain was stuck in idle. “He still had these network connections that could in principle be recruited,” Schiff explains, “but the brain was not regulating its own level of activity properly.” The central thalamus may act as a gatekeeper, and the added stimulation kicks up the level of activation. Schiff suspects that once consciousness is restored, the brain then begins to repair itself, accounting for the patient’s gradual improvement.
The researchers are recruiting 11 more patients who have survived a traumatic brain injury and been in an MCS for at least a year with only intermittent awareness. They have been inundated with potential candidates. Most are young victims of attacks or accidents. Until they better understand it, the team will not use the technique on stroke survivors. Patients in a permanent vegetative state (like Terri Schiavo) can never be involved.
No one knows how many people are in a minimally conscious or vegetative state—perhaps as many as 280,000 in the United States alone. Such patients are not tracked, and up to 40 percent may be wrongly diagnosed. Many are warehoused in nursing homes, without access to treatment or rehabilitation.
Evidence is mounting that some patients who appear unconscious may be able to reconnect to the world. Giacino and Schiff’s 2005 neuroimaging study, which included the patient described in Nature, showed that the language-processing areas of some patients in MCS respond to spoken words. In another study, the brain of a patient who appeared to be in a vegetative state responded just like a healthy person’s when asked to imagine playing a game of tennis. Motor-control areas lit up, suggesting some level of comprehension. “These are the forgotten people,” Rezai says, “and now medical technology is allowing us to open a new chapter in their lives.”
See related Web-exclusive feature: Diagnosing Consciousness
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