Table 1.

Additional Key Terms

TERM	DEFINITION
Coma	a state of being in which a person is unconscious. The person is both unawake and unaware, with the general behavioral characteristics of closed eyes, immobility, and lack of reflexive movements
Vegetative state (VS)	similar pathophysiology as a coma (i.e., the patient remains unaware) except there generally seems to be some functioning of the upper brainstem, including the presence of sleep-wake cycles. Patients in this state of consciousness may open and close their eyes, breathe without assistance, and reflexively respond to stimuli, thus appearing awake. While a VS is typically seen as transitory between coma and some level of conscious recovery, it is possible that a person may remain in a VS for several weeks or months.
Persistent vegetative state (PVS)	VS state lasts more than 30 days
Permanent VS	VS state lasts more than three months.
Brain death	refers to the permanent cessation of critical neurological functions
Stupor	a state of excessively long or deep unresponsiveness where a patient can only be briefly aroused by vigorous, physical stimulation such as repeated shaking, talking loudly, or pinching.
Delirium	is a neurocognitive disorder that presents as an acute and fluctuating change in behavior secondary to impairments in consciousness and cognition
Dementia	an acquired chronic disorder of executive function in at least one cognitive domain (e.g. memory, language, judgment, or attention).