Persistent vegetative stateA persistent vegetative state (or PVS) is a condition of patients with severe brain damage in whom coma has progressed to a state of "wakefulness without awareness". The term was introduced by two doctors in 1972 to describe a syndrome that seemed to have been made possible by medicine's increased capacities to keep patients' bodies alive. A persistent vegetative state is not the same as coma, the major distinction being that coma sufferers cannot breathe on their own.
Patients in a persistent vegetative state are usually considered to be unconscious and unaware, but exhibit sleep-wake cycles and some behaviors that can be construed as arising from partial consciousness, such as grinding their teeth, swallowing, smiling, shedding tears, grunting, moaning, or screaming without any apparent external stimulus. Their heads and eyes can track moving objects or turn towards a sound. Commonly, close family members who visit the patient frequently will detect evidence of awareness when doctors with limited patient contact will deny it. Many people have recovered from PVS, and there is evidence that eye tracking is often the earliest symptom of recovery.
PVS is not recognized as death in any known legal system.