A study reported in Neurology found that certain jobs that involved mental challenges and demanded a more complex work with other people like social work, law, graphic designing and architecture, helped keep the brain Allan Ajifo/ Flickr

Many people who are brain-injured and live in the gray area between life and death -- often called a vegetative state -- are usually left in hospitals, with doctors clueless about whether such patients would ever regain consciousness.

But this might change soon as a study conducted by University of Copenhagen has highlighted that doctors can use a simple brain scan device to predict whether such patients would wake up ever, according to a STAT report.

Around 200,000 to 300,000 people in the United States are currently living in the gray zone, which is either a vegetative state or a minimally conscious state.

Patients in vegetative state often look awake but are unaware of the surroundings and do not respond to external stimulus such as touch and sound; however, those with minimal consciousness sometimes do respond to such stimulus.

Those patients in the minimal consciousness state are more likely to wake up.

Scientists involved in the study analysed 131 brain-injured patients among which 49 in a vegetative state, 65 in minimal conscious state, and 17 who were recovering from minimal consciousness. The scientists then used a brain scan device called positron emission tomography, or PET, imaging, which could detect the brain activity of the patients.

The study found that the brain activity of these patients in different states did show a remarkable difference.

The patients in vegetative state had only 38 percent of brain activity, whereas minimally conscious patients had 56 percent of the average brain activity.

The current technique used by a majority of doctors, according to study researcher Ron Kupers, is the behavioural analysis of patients, which may be open to interpretations and, therefore, inaccurate.

However, PET machine, according to him, is a far more accurate method of predicting whether such patients have any chance of waking up.

The scientists kept a standard of 41 percent brain activity and based on that correctly identified 94 percent of the brain-dead patients who would wake up within a year.

The study also suggested that a higher brain activity would make it easier for a patient to shift from one state to another (unconsciousness to consciousness).