A relief for PVS?

A specialized magazine called Neuro Rehabilitation published that some South African scientists concluded that people suffering of persitent vegetative state (or PVS) can actually "wake up" transitorily and even speak after taking certain pills to battle insomnia for several days.

They came up with this conclusion after giving three PVS patients a pill called Zolpidem during the morning during some days; after 20 minutes of having swallowed the pill, the patients allegedly experienced symptoms of rehabilitation, as two of them were able to answer some simple questions during its effects, and the other one, who persistently screams while suffering the PVS condition, just remained quiet and even watched TV. Unfortunately, after some minutes, such effects disappeared and the patients did return to their PVS situation.
Although this experiment has not satisfied many experts, some neurologists claim that this effect may occur because not all of the brain tissue is dead, just asleep, so maybe taking the pill leads to a momentary awakening of some brain tissue that has not been in use. Other specialists argue that maybe the patients subject to this study were not suffering a real PVS condition.
Is this for real, or it's just a mistaken conclusion by the South African scientists? Since I'm not a neurologist, I can't show any evidence to assume whether the conclusion is accurate or not, although I see this as a first step. What I can say is that I'm sure that we all human beings wish that our science continues to develop, and that way, our scientists will discover effective and a permanent cure for PVS and many other illnesses and conditions that frustrate many people of having a joyful life.