West Haven criteria for altered mental status in hepatic encephalopathy
Grade 0 Minimal hepatic encephalopathy, lack of detectable changes in personality or behavior; no asterixis.
Grade 1 Trivial lack of awareness, shortened attention span, sleep disturbance, altered mood, and slowing the ability to perform mental tasks; asterixis may be present.
Grade 2 Lethargy or apathy, disorientation to time, amnesia of recent events, impaired simple computations, inappropriate behavior, and slurred speech; asterixis is present.
Grade 3 Somnolence, confusion, disorientation to place, bizarre behavior, clonus, nystagmus, and positive Babinski sign; asterixis usually absent.
Grade 4 Coma, lack of verbal, eye, and oral response to stimuli.
Emergency Management in Neurocritical Care: Chapter 17 Metabolic Encephalopathies, by Edward Manno