This is astounding. The sleeping pill zolpidem (sold in the US as Ambien) awakens people in persistent vegetative states as often as 60% of the time.

Across three continents, brain-damaged patients are reporting remarkable improvements after taking a pill that should make them fall asleep but that, instead, appears to be waking up cells in their brains that were thought to have been dead. In the next two months, trials on patients are expected to begin in South Africa aimed at finding out exactly what is going on inside their heads. Because, at the moment, the results are baffling doctors. [...]

I see Louis before his daily medication, yet he is conscious where once he would have been comatose. Almost blind because of a separate and deteriorating condition, there is a droop to one side of his mouth and brow because of brain damage. His right arm is twisted awkwardly into his side.

Louis is given a pill, and I watch. It is 8.30am. After nine minutes the grey pallor disappears and his face flushes. He starts smiling and laughing. After 10 minutes he begins asking questions. [...] A couple of minutes later, his right arm becomes less contorted and the facial drooping lessens. After 15 minutes he reaches out to hug Sienie.

These aren't people in regular comas (unconscious, but with measurable low-level brain activity), these are people in PVS, with brain scans showing zero activity in large parts of the brain. After taking zolpidem, these dead sections wake back up.

It appears that the recipients need to take the drug daily to maintain consciousness, but some patients are going on 7 years without any signs of decline (unlike with L-dopa, as in "Awakenings"). It doesn't restore necrotic brain cells, but it does seem to stimulate dormant ones, even in people with non-PVS brain damage. As in:

I meet 22-year-old Janli de Koch, whose eyesight was damaged in a car accident in Switzerland in December 2004. The injury resulted in a restriction of her visual field to two corners of her eyes; she cannot see below a certain point, so that she bumps into things and falls over. Last month, she was prescribed zolpidem and now says she can already see more than she used to.

Recipients are also showing improvement in motor function and balance.

A sleeping pill treatment for vegetative states and serious brain damage. That's just... wow.