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New hope for minimally conscious patients
Test case may change standard of care
The outlook for patients in a minimally conscious state (MCS) may have new potential, according to a team of physicians, scientists, and ethicists who used deep brain stimulation (DBS) to improve function in a man's still-responsive brain networks.
The 38-year-old man had been unable to communicate or eat by mouth for more than six years, since sustaining severe brain damage from an assault. According to the findings of the New York-Presbyterian/Weill Cornell team that conducted the experimental procedure, the man now eats by mouth and can communicate with words and gestures. The use of thalamic stimulation has not been applied to this patient population before, the authors state.
Writing in a recent issue of Nature1, lead author Nicholas D. Schiff, MD, says that if the results can be replicated in other patients, it might change the standard of care for under-responsive MCS patients. Most patients in MCS are in long-term nursing facilities and don't receive rehabilitative therapy because of their lack of responsiveness and poor prognosis. Schiff, a neurologist and neuroscientist at New York-Presbyterian/Weill Cornell, developed the concept of DBS more than 10 years ago, and teamed with experts from JFK Johnson Rehabilitation Institute Center for Head Injuries in Edison, NJ, and the Cleveland Clinic Center for Neurological Restoration.
The patient who underwent the unique therapy has asked that he not be identified. However, his mother released a statement in which she says that because of the DBS surgery and rehabilitation, her son "can eat, express himself, and let us know if he is in pain. He enjoys a quality of life we never thought possible."
Prior to the use of DBS, researchers write, the patient demonstrated inconsistent communication, including only slight eye or finger movements. He also was fed through a tube. Now, he uses words and gestures, responds to questions quickly, chews and swallows food, and can perform some complex movements — including those required for drinking from a cup or brushing hair — that he was unable to accomplish before.
The DBS was accomplished by surgical implanting of electrodes into the brain to deliver electrical impulses. The procedure has been used to relieve the symptoms of conditions such as Parkinson's disease, dystonia, obsessive-compulsive disorder, and depression. This first DBS procedure is part of a pilot study approved by the FDA that will include 12 patients in post-traumatic MCS.
"The work challenges the existing practice of early treatment discontinuation for this patient population and also changes the approach to assessment and evaluation of the MCS patient," says Schiff.
Joseph Fins, MD, professor of medicine and director of medical ethics for New York-Presbyterian/Weill Cornell, says the results of this experimental treatment give hope that patients may "recapture a lost personhood as they regain an ability to communicate. This clearly speaks to an ethical mandate to further such clinical trials designed to improve function in these patients."
MCS – Glimpses of consciousness
MCS, unlike persistent vegetative state (PVS) or coma, is distinct in that patients show intermittent signs of awareness and may even attempt to communicate using simple words or signals. However, these glimpses of consciousness are usually rare and fleeting.
The authors of the New York study say estimates are that 100,000 to 300,000 patients with traumatic brain injury are now diagnosed as MCS. Under the current standard of care, most do not receive active rehabilitation.
"We knew that some patients in MCS, including our subject, retain functioning brain networks above the brainstem," explains Schiff. "Activity within these integrated neural networks is supported by cells in the central thalamus, which is thought to be one key to adjusting brain activity as it responds to cognitive demands."
Schiff says while the outcome thus far in this study is encouraging, more study is necessary to know if other patients will benefit, and what the ultimate outcome for the study patient might be.
"Without further study, we have no means of knowing for sure that the functional improvements we have observed will be seen in other subjects, yet we expect that we will find other patients who will respond," Schiff says. "We can say that this patient's recovery of oral feeding and communication abilities was strongly linked to the DBS. But even more encouraging is the fact that the patient's functional gains continued even during the off-phase [periods after the electrodes were implanted when DBS was not actively used], suggesting a carryover effect from treatment."
Fins says that if the treatment continues to result in positive effects, "it will force us to take a second look at each case and — for appropriate patients — move away from the therapeutic nihilism that has so plagued this population, most of whom are ignored, receiving what is euphemistically described as 'custodial care.'"
1. Schiff ND, Giacino JT, Kalmar K, et al. Behavioral improvements with thalamic stimulation after severe traumatic brain injury. Nature 2007;448:600-603.