Scientists have used a portable device that tracks changes in brain waves to communicate with people in a vegetative state, some of whom have been locked in their bodies for more than a year.
In a study published last year in the New England Journal of Medicine, researchers showed it was possible to communicate with and detect awareness in people in a vegetative state using functional magnetic resonance imaging or fMRI.
The team then tried far less expensive, portable equipment to get a better idea of how many people classified as being in a vegetative state are actually aware of their surroundings.
The researchers instructed 16 people in a vegetative state to imagine they were making a fist with their right hand or wiggling their toes, and then measured brain activity while electrodes were attached to their scalp.
"It was possible to detect that these patients were actually aware" despite being diagnosed as being "entirely unconscious" using standard clinical assessments, said Professor Adrian Owen of the Center for Brain and Mind at the University of Western Ontario. Findings from the newer study were published in the British journal Lancet on Wednesday.
Patients in a persistent vegetative state have periods of wakefulness, but they are completely unresponsive and are thought to be unaware.
"We don't actually know how many vegetative patients there are. It's now possible to find that out," said Dr. Damian Cruse of the University of Western Ontario, who led the study.
Using an MRI machine requires moving patients from nursing home facilities to academic medical centers for the costly scans, and some have metal implants, ruling out use of magnetic-based scanners.
Cruse devised a way to assess patients using a portable electroencephalography (EEG) device, which is used to record electrical activity in the brain. The devices also cost far less, from $25,000 to $90,000, compared with some $3 million for an MRI machine.
