Functional MRI Helps Nonresponsive Patients 'Talk'

Megan Brooks

August 20, 2013

Using functional MRI (fMRI), researchers have shown for the first time that patients who are nonresponsive because of severe brain injury can selectively focus their attention to follow commands and communicate.

"One patient who had maintained a clinical diagnosis of vegetative state over a 12-year period prior to scanning, and also subsequent to it, was able to use attention to correctly communicate answers to several binary (yes/no) questions. In this way, the patient demonstrated that he was aware of his identity and whereabouts," Lorina Naci, PhD, from The Brain and Mind Institute at Western University in London, Ontario, Canada, told Medscape Medical News.

"In 2 different hospital visits, five months apart, not only were we able to communicate with the patient but found that he was also aware of his environment, meaning he could maintain coherent thoughts and lead a rich mental life," Dr. Naci added.

The study was published online August 12 in JAMA Neurology.

A Rich Mental Life

This group from the University of Western Ontario, with senior author Adrian M. Owen, PhD, previously reported using fMRI to have patients previously considered in a vegetative state apparently answer "yes" or "no" questions by visualizing themselves doing actions known to activate different parts of the brain. They have also previously reported using electroencephalography (EEG) at the bedside for this purpose, although their interpretation of their findings was later challenged by another group.

Their current report involved a convenience sample of 3 patients: 2 diagnosed as being in a minimally conscious state and 1 diagnosed as being in a vegetative state. All 3 patients were entirely behaviorally nonresponsive to repeated independent neurologic bedside examinations.

The researchers had all patients undergo fMRI while being asked to selectively attend to auditory stimuli, which would convey their ability to follow commands and communicate.

Indeed, they found that all 3 patients could follow a simple command (to count or relax); their brain images showed "significantly more activation following the instruction to count than relax," the investigators say.

"The significant brain activity observed for each patient during the command-following task confirmed that he understood and followed the commands and was able to pay attention to some words while ignoring others that were irrelevant for the task," they write.

Dr. Lorina Naci

In addition, in the communication task during fMRI, 1 of the patients in a minimally conscious state and the patient in the vegetative state were also able to correctly answer yes/no questions, such as "Are you in a hospital?" or "Are you in a supermarket?"

"Convincing" Data

This novel fMRI technique "takes communication with some patients who are assumed to be in a vegetative state to the next level," Dr. Naci told Medscape Medical News. "It will make detecting who is conscious and who is not faster and more reliable, and for those who are conscious, communicating their wishes will be much easier."

She cautioned that more study is needed. "In this study, we establish a proof of principle that some entirely behaviorally nonresponsive patients can use selective attention to communicate. We are now undertaking patient cohort studies to determine what proportion of nonresponsive patients retain these high-level cognitive abilities and can successfully use this technique," Dr. Naci said.

The data here are "convincing," writes James L. Bernat, MD, from the Geisel School of Medicine at Dartmouth in Hanover, New Hampshire, in 1 of 2 editorials published with the study.

He thinks patients discovered by fMRI studies to have been wrongly diagnosed as being in vegetative state "deserve our efforts to reassure them that we know they are aware, to establish a reliable communication system to the fullest extent possible, and to adequately address their medical, emotional, and palliative care needs just as we currently do with our awake and aware but profoundly paralyzed patients with LIS [locked-in syndrome]."

Another implication of the study is the need to incorporate fMRI and other valid functional neuroimaging and electroencephalographic data documenting evidence of awareness into current diagnostic criteria for the syndrome of vegetative state, Dr. Bernat says.

"Once there is general acceptance that the fMRI data from the studies published during the past 7 years conclusively demonstrate at least some level of awareness in the subset of patients with these findings, these data should be accepted as evidence that the patient's diagnosis is MCS [minimally conscious state], not VS [vegetative state]," Dr. Bernat writes.

This study also highlights the need to "optimize the design, data acquisition, and signal processing in experimental fMRI paradigms to generate valid and consistent data that accurately record the conscious activity of patients with severe brain damage," he adds.

A Paradigmatic Shift?

In a second, separate editorial, Kenneth M. Heilman, MD, from the Department of Neurology, University of Florida College of Medicine in Gainesville, says the finding that fMRI may be used to communicate with patients who have a total locked-in syndrome "may lead to a paradigmatic shift such that with the further development of prostheses, these unfortunate patients, as well as patients with other forms of locked-in syndromes, will be able to open the door to end their isolation."

"Cortically controlled motor prostheses are being developed to restore functions lost by the damage caused by neurological diseases and injuries. Several studies have already shown encouraging results, but barriers to clinical translation still remain," Dr. Heilman writes.

The study was supported by the DECODER Project, the European Commission in the 7th Framework Programme, the James S. McDonnell Foundation, and the Canada Excellence Research Chairs Program. The authors and editorial writers have disclosed no relevant financial relationships.

JAMA Neurol. Published online August 12, 2013. Abstract   Editorial Editorial


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