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Adrian Owen’s pioneering research into the consciousness of physically unresponsive patients has captured widespread media attention in recent years, including from Jerome Groopman, who described Owen’s work in a 2007 New Yorker article. As Owen was quoted then, “The thought of coma, vegetative state, and other disorders of consciousness troubles us all because it awakens the old terror of being buried alive. Can any of these patients think, feel, or understand those around them? And, if so, what does this tell us about the nature of consciousness itself?”

At that time, Owen had shown through fMRI studies that some coma patients, who were previously presumed to be unconscious by virtue of being physically unresponsive to any stimulus, actually had awareness. Images captured through fMRI showed blood flow indicating normal brain activity in response to specific questions and commands. Owen suggested that as many as 20% of “vegetative state” patients might be misdiagnosed.

Despite the astounding implications for thousands of such patients worldwide, many will never undergo fMRI screening. Beyond the expense and limited availability of scanners that make it a prohibitive procedure, many patients who have suffered traumatic injuries have metal plates or pins that disqualify them as MRI candidates. Or, lacking bodily control, they are unable to remain still long enough for useful images to be captured.

In a recent article “Bedside detection of awareness in vegetative state: a cohort study” published in The Lancet (Nov 2011), Owen and Cruse now employ a low-cost, portable technology – electroencephalography (EEG; which has been around for 100 years) – to detect consciousness at the patient bedside. Instead of blood flow, EEG measures electrical current in the brain of a patient. Each of their subjects, with EEG nodes attached to their scalps, were asked 200 times in 20 minutes to imagine squeezing their hand into a fist and to imagine wiggling their toes.

The study of 16 vegetative state patients confirmed Owen’s previous estimate that some 20 percent of people whose behavior would indicate otherwise do actually have awareness – they can hear, understand, and respond to commands. In one televised news interview Cruse said that, though EEG is not a new technology, “the advance is making use of machine learning to interpret the patterns of brain activity.” The studies present the possibility that, for the cost of an electric wheelchair, families could use an EEG at home to “actually have a conversation with a patient who externally doesn’t have ability to communicate,” he said.

F1000 reviewer Nicolas Bruder calls the work exceptional, but warns that, though the authors claim that EEG is cheap, can be done at the bedside, and is available almost everywhere, there is a learning curve that might preclude use by families at home:

The methods used to generate the appropriate stimulus and interpretation of the data need training, time, and neurophysiological and neurocognitive expertise to avoid biases or misinterpretation of the data.

Bruder also points out one curious aspect of the study: While 3 of 16 “vegetative” patients were able to generate appropriate EEG responses to stimulus, three controls – volunteers from the university’s School of Social Sciences – for some reason, did not. This shows that “a negative EEG finding should be interpreted with caution.”

Nevertheless, these discoveries are significant enough to indicate that a change in the clinical classification of disorders of consciousness may be needed. Bruder writes:

There may be some patients with a state of severe ‘functional locked-in syndrome’ after brain injury who will need specific medical management compared to vegetative state or minimally conscious state patients.