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A vegetative state is a condition in which someone is awake, but not aware. People usually emerge from a coma into such a state as their brains slowly recover from injury and they start to become more alert and aware. From this state, a patient can move into a minimally conscious state and then into a state of full consciousness. However, sometimes patients do not recover from this state because their brains are too badly damaged.
Many different events can cause damage to the brain resulting in coma including trauma, infection, and exposure to neurotoxins. When a patient is in a vegetative state, higher brain function is not observed, but the patient's brainstem is intact. This means that the patient has some basic reflexes and can usually breathe independently, but cannot communicate, understand spoken language, or engage purposefully with the surrounding environment.
Diagnosing a vegetative state is complicated, and misdiagnosis happens. This is extremely problematic because diagnosing a patient incorrectly can literally be the difference between life and death. One study showed people in a supposedly vegetative state who were able to learn, for example, which meant that their higher brain functions were not only intact, but working. A number of tests can be performed to screen patients who have experienced brain injuries to determine their level of consciousness, but the test results are not always entirely reliable; patients in the 2009 study discussed above had been diagnosed and confirmed as being in a vegetative state, for instance, despite the fact that they were not.
When a patient remains in this condition for more than a month, the term “persistent vegetative state” may be used to describe the patient. It is possible to recover after more than a month, but the chances become increasingly slim as time goes on. After a year or more, the patient is said to be in a permanent vegetative state. However, even this is a bit of a misnomer, because there have been recorded instances in which patients have recovered from supposedly permanent states.
Patients in this state have sleep-wake cycles, may open their eyes, can laugh, cry, or smile, and will react to unpleasant stimuli. However, they are not conscious of their surrounding environment. They also require nursing support because while they can breathe on their own, they cannot feed themselves and they have difficulty with most daily tasks.
When someone experiences a brain injury which results in a presumed coma, vegetative state, or minimally conscious state, it is important that the patient have advocates. It is critical to be very thorough during the diagnosis to confirm that it is correct, and to avoid a situation such as misdiagnosing someone with locked in syndrome, in which the patient is fully awake and aware, but is unable to move. It is also important to note that none of these conditions are equivalent to brain death.