Real Life Awakenings

EEG responses are reliable markers of motor imagery

(RxWiki News) What level of awareness does a person have when in a vegetative state? Can a person in a coma ever wake up?

These are questions that trouble both the medical community and family members of such patients. But new research shows promise for people in such minimally conscious states.

"Ask about new treatments for comatose patients."

Adrian Owen and Damian Cruse of Cambridge University in England led a study at two European centers. Assessing 16 patients in a vegetative state from brain injury and 12 healthy control subjects, the research team use electronic EEG waves to detect awareness.

"The EEG method that we developed is cheap, portable, widely available, and objective," the researchers wrote. "It could allow the widespread use of this bedside technique for the rediagnosis of patients who behaviourally seem to be entirely vegetative, but who might have residual cognitive function and conscious awareness."

Researchers then had patients complete a task in which they were required to imagine movements of their right-hand and toes to command, and analyzed the EEG responses of each patient looking for robust evidence of appropriate, consistent, and statistically reliable markers of motor imagery, like those found in healthy, conscious control subjects.

19 percent of the vegetative patients could repeatedly and reliably generate appropriate responses to two distinct commands, despite being behaviorally unresponsive and unable to report their own awareness to others.

This simple test has important promise for enabling doctors to establish a patient's level of consciousness. Although the study and results were small, the researchers maintain that many patients in a vegetative state are misdiagnosed.

The study was published in a recent issue of The Lancet

Review Date: 
December 6, 2011