"Just because someone can answer yes or no doesn't mean we know their inner mental world," said Owen. "We don't know if they're depressed or if they want to live or die."
Another ethical concern is whether family members will benefit from knowing the inner conscious state of their loved one, and whether knowing will either help move them towards making a decision to stop or continue treatment.
"While an additional test to reassure families is something we negotiate frequently, it is important to avoid the trap of continually asking for one more test," said Dr. Shlomo Shinnar, director of the comprehensive epilepsy management center at Montefiore Medical Center in New York.
A majority of the cases within the study showed no form of consciousness based on EEG results. The goal among families and doctors should be to set reasonable expectations about the next step before turning to the test, Shinnar added.