neurologic disorders
Vegetative State and Minimally Conscious State
Prognosis
Prognosis varies somewhat by cause and duration of the vegetative state. Prognosis may be better if the cause is a reversible metabolic condition (eg, toxic encephalopathy) than if the cause is neuronal death due to extensive hypoxia and ischemia or another condition. Also, younger patients may recover more motor function than older patients but not more cognition, behavior, or speech. Recovery from a vegetative state is unlikely after 1 month if brain damage is nontraumatic and after 12 months if brain damage is traumatic. Even if some recovery occurs after these intervals, most patients are severely disabled. Rarely, improvement occurs late; after 5 years, about 3% of patients recover the ability to communicate and comprehend, but even fewer can live independently; no patients regain normal function. If a vegetative state persists, most patients die within 6 months of the original brain damage. The cause is usually pulmonary infection, urinary tract infection, or multiple organ failure, or death may be sudden and of unknown cause. For most of the rest, life expectancy is about 2 to 5 years; only about 25% of patients live > 5 years. A few patients live for decades. Most patients tend to recover consciousness but to a limited extent depending on how long the minimally conscious state has lasted. The longer it has lasted, the less chance of patients recovering higher cortical function. Prognosis may be better if the cause is traumatic brain injury. Rarely, patients regain clear but limited awareness after years of coma, called awakenings by the news media. 