From the NY Times:

It seems backwards but Ambien and certain other medications are being studied to see if they can help vegetative people recover from brain trauma.

The first report of a zolpidem awakening came from South Africa, in 1999. A patient named Louis Viljoen, who, three years before, was declared vegetative after he was hit by a truck, had taken to clawing at his mattress during the night. Thinking he was suffering from insomnia, his family doctor suggested zolpidem to help him sleep. But 20 minutes after his mother ground the tablet up and fed it to him through a straw, Viljoen began to stir. His eyes, which normally wandered the room, vacant and unfocused, flickered with the light of consciousness. And then he began to talk (his first words were “Hello, Mummy”), and move (he could control his limbs and facial muscles). A few hours later he became unresponsive. But the next day, and for many days after that, zolpidem revived him, a few hours at a time.

Here was a case worthy of Hollywood: three years was well past the point at which doctors would expect any sort of spontaneous recovery. Viljoen awoke with the ability to speak in complete sentences. Not only did he recognize his mother, but he also recognized the voices of people who had spoken to him only when he was apparently vegetative. He remembered nothing of the mysterious realm he kept receding back into. When doctors asked him what it was like to slip away, he said he felt no changes at all. But he could recall conversations from the previous day’s awakening, along with bits and pieces of his former life: his favorite rugby team, specific matches he attended, players that he rooted for and against. As time passed, his cognition improved. He could laugh at jokes, and his awakenings stretched from a few hours to entire days. Eventually, he no longer needed zolpidem.

Other medications used for anxiety and Parkinson’s are also bring looked at. Not all patients respond in the same way and what is considered consciousness seems to change over time or with who you speak to. But it’s still hopeful to those who’s loved ones appear to be brain dead or in a vegetative state.