After suffering from a severe brain injury, patients often slip into a vegetative or minimally-conscious state, sustained by life support. So their clinicians begin a desperate pursuit for any hint of awareness — a finger lifted or a toe wiggled. But, heeding no signs of visible consciousness, healthcare providers are faced with one hefty question from the patients’ loved ones: “When will they wake up?”

The answer has always been quite bleak and uncertain. But a new study published in The New England Journal of Medicine shows this may no longer always be the case. Researchers used extensive brainwave analysis by electroencephalography (EEG) to analyze degrees of consciousness in 104 patients with brain injuries. In response to spoken commands given to patients a few days following their injury, EEG detected brain activity in 16, or 15%, of the 104 patients. However, although these patients showed a cognitive response, their bedside examiners could not observe a visible motor response.

Some 44% of the patients who displayed EEG-detected brain activity could function independently after one year of rehabilitation, determined by a level of four or above on the Glasgow Outcome Scale. Only 14% of those who did not show signs of brain activity could achieve this level of functionality within the same timeframe. The findings shed light on how some patients recovering from a brain injury could seem completely unresponsive yet fairly active and aware of what is being said about them in an intensive care unit.

While the EEG approach is not yet advanced enough for providers to answer that harrowing “when will they wake up?” question with a satisfying response, some experts believe it has the potential to change standard practices and advise treatment, The New York Times reports. Others believe the technique is far from perfect, and it is too early to judge its effectiveness. However, with further advances in techniques like these, neuroscientists are on the cusp of understanding the association between brain activity and the possibility of recovery.