Patients in a vegetative state have intervals of wakefulness, but seem to be unaware of themselves or their surroundings, a Lancet study has found. The researchers did an electroencephalograph (EEG) on patients with both traumatic and non-traumatic brain injury in a vegetative state. The researchers used a test that involved motor imagery, encouraging the patients to imagine moving their right-hand fingers and toes. Such tests are universally considered a reliable indicator of awareness.

The researchers found that 3 (19%) of the 16 patients tested who were diagnosed as being in a vegetative state could reliably and repeatedly respond to EEG commands, despite the fact that they were behaviourally unresponsive. The study found that many vegetative patients are misdiagnosed. The researchers wrote that a new EEG method that is “cheap, portable, widely available, and objective” could be used to rediagnose patients who, seem “vegetative” in their behaviour but who might still have some awareness and cognitive function. ~ Lancet, Nov 10