brain, spinal cord, and nerve disorders
Vegetative State
Introduction
A vegetative state occurs when the cerebrum (the part of the brain that controls thought and behavior) no longer functions, but the hypothalamus and brain stem (the parts of the brain that control vital functions, such as sleep cycles, body temperature, breathing, blood pressure, heart rate, and consciousness) continue to function. Thus, people open their eyes and appear awake but otherwise do not respond to stimulation in any meaningful way. Most commonly, a vegetative state is caused by severe brain damage due to a head injury or a disorder that deprives the brain of oxygen, such as cardiac or respiratory arrest. People in a vegetative state can open their eyes, but they cannot speak or do things that require thought or conscious intention, and they have no awareness of themselves or their environment. Doctors diagnose a vegetative state only after they observe people for a period of time and on more than one occasion and do not find any evidence of awareness. People in a vegetative state require comprehensive care, including good nutrition and measures to prevent problems that result from not being able to move (such as pressure sores). The vegetative state is rare. A vegetative state that lasts for more than 1 month is considered a persistent vegetative state. Most people with a persistent vegetative state do not recover any mental function or ability to interact with the environment in a meaningful way. However, a few people with a persistent vegetative state improve enough that the diagnosis is changed to Minimally Conscious State . In people in a minimally conscious state, awareness is severely but not completely impaired. When any recovery occurs, the cause was usually brain damage due to a head injury ( Overview of Head Injuries ), not a disorder that resulted in the brain being deprived of oxygen. Also, recovery is often very limited. For example, people may reach for any and all objects or may utter the same word over and over. Rarely, people in a persistent vegetative state due to a head injury continue to slowly improve over months to years. How many people are in a vegetative state is unknown, but about 25,000 adults and almost 10,000 children in the United States are thought to have this disorder. 