Whether or not there is any conscious awareness with a patients vegetative state is a prominent issue. Three completely different aspects of this should be distinguished. First, some patients can be conscious simply because they are misdiagnosed (see above). In fact, they are not in vegetative states. Second, sometimes a patient was correctly diagnosed but is then examined during the early stages of recovery. Third, perhaps some day the notion itself of vegetative states will change so to include elements of conscious awareness. Inability to disentangle these three example cases causes confusion. An example of such confusion is the response to an experiment using functional magnetic resonance imaging which revealed that a woman diagnosed with PVS was able to activate predictable portions of her brain in response to the testers requests that she imagine herself playing tennis or moving from room to room in her house. The brain activity in response to these instructions was indistinguishable from those of healthy patients.In 2010, Martin Monti and fellow researchers, working at the MRC Cognition and Brain Sciences Unit at the University of Cambridge, reported in an article in the New England Journal of Medicine that some patients in persistent vegetative states responded to verbal instructions by displaying different patterns of brain activity on fMRI scans. Five out of a total of 54 diagnosed patients were apparently able to respond when instructed to think about one of two different physical activities.
One of these five was also able to "answer" yes or no questions, again by imagining one of these two activities. It is unclear, however, whether the fact that portions of the patients brains light up on fMRI could help these patients assume their own medical decision making.In November 2011, a publication in The Lancet presented bedside EEG apparatus and indicated that its signal could be used to detect awareness in three of 16 patients diagnosed in the vegetative state. Treatment
Currently no treatment for vegetative state exists that would satisfy the efficacy criteria of evidence-based medicine. Several methods have been proposed which can roughly be subdivided into four categories: pharmacological methods, surgery, physical therapy, and various stimulation techniques. Pharmacological therapy mainly uses activating substances such as tricyclic antidepressants or methylphenidate. Mixed results have been reported using dopaminergic drugs such as amantadine and bromocriptine and stimulants such as dextroamphetamine. Surgical methods such as deep brain stimulation are used less frequently due to the invasiveness of the procedures. Stimulation techniques include sensory stimulation, sensory regulation, music and musicokinetic therapy, social-tactile interaction, and cortical stimulation. Zolpidem
There is limited evidence that the hypnotic drug zolpidem has an effect. The results of the few scientific studies that have been published so far on the effectiveness of zolpidem have been contradictory. Epidemiology
In the United States, it is estimated that there may be between 15,000 and 40,000 patients who are in a persistent vegetative state, but due to poor nursing home records exact figures are hard to determine.