Persistent Vegetative State: Definitions and Decisions Persistent Vegetative State:

First described in the literature by Jennett and Plum in 1972, the vegetative state is best described as a clinical condition in which a patient is unaware of his self and environment. There is no evidence of voluntary behavioral responses to visual, audible, or noxious stimuli, and patients show no ability for language comprehension or expression. Patients are considered to be “awake but not aware. ” According to William James ’ definition of consciousness, which requires both wakefulness and awareness, patients in PVS are considered to be unconscious. However, unlike coma, a patient has continued sleep-wake cycles and complete or partial functioning of the hypothalamus and brain-stem. Patients in PVS continue to breathe on their own, but cannot perform the voluntary actions of chewing and swallowing. These patients can survive months to years with nutrition and hydration as well as good nursing care. Diagnosis: The diagnosis is made primarily clinically. EEG plays a small role in diagnosis, showing polymorphic delta and theta waves, similar to coma. Small studies using PET imaging show considerably less (50%) glucose metabolism in the cerebral cortex. But, the sources I found considered PET imaging to be a research tool and not well-documented enough to be used routinely in diagnosis. Vegetative state lasting greater than one month is considered to be a persistent vegetative state. The term “permanent vegetativ