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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Consciousness | 14/18 | https://en.wikipedia.org/wiki/Consciousness | reference | science, encyclopedia | 2026-05-05T13:40:02.432894+00:00 | kb-cron |
=== Assessment === In medicine, consciousness is examined using a set of procedures known as neuropsychological assessment. There are two commonly used methods for assessing the level of consciousness of a patient: a simple procedure that requires minimal training, and a more complex procedure that requires substantial expertise. The simple procedure begins by asking whether the patient is able to move and react to physical stimuli. If so, the next question is whether the patient can respond meaningfully to questions and commands. If so, the patient is asked for their name, current location, and current day and time. A patient who can answer all of these questions is said to be "alert and oriented times four" (sometimes denoted "A&Ox4" on a medical chart), and is usually considered fully conscious. The more complex procedure is known as a neurological examination, and is usually carried out by a neurologist, or specialist nurses, in a hospital setting. A formal neurological examination runs through a precisely delineated series of tests, beginning with tests for basic sensorimotor reflexes, and culminating with tests for sophisticated use of language. The outcome may be summarized using the Glasgow Coma Scale, which yields a number in the range 3–15, with a score of 3 to 8 indicating coma, and 15 indicating full consciousness. The Glasgow Coma Scale has three subscales, measuring the best motor response (ranging from "no motor response" to "obeys commands"), the best eye response (ranging from "no eye opening" to "eyes opening spontaneously") and the best verbal response (ranging from "no verbal response" to "fully oriented"). There is also a simpler pediatric version of the scale, for children too young to be able to use language. Alternatives to the GCS, given its limitations in patients with severely impaired alertness such as in the intensive care unit, have been proposed. The FOUR score appears to provide superior responsiveness, reliability, and predictive performance compared to the GCS when used to assess patients with very low consciousness due to acute brain injury or critical illness. In addition to assessment of brainstem functions, the superior psychometric performance of the FOUR score appears partly attributable to the inclusion of assessment of visual pursuit as part of the eye response component, which if intact, indicates a level of coritical functioning (and thus, awareness) in seemingly unresponsive patients. In 2013, an experimental procedure was developed to measure degrees of consciousness, the procedure involving stimulating the brain with a magnetic pulse, measuring resulting waves of electrical activity, and developing a consciousness score based on the complexity of the brain activity.
=== Disorders === Medical conditions that inhibit consciousness are considered disorders of consciousness. This category generally includes minimally conscious state and persistent vegetative state, but sometimes also includes the less severe locked-in syndrome and more severe chronic coma. Differential diagnosis of these disorders is an active area of biomedical research. Finally, brain death results in possible irreversible disruption of consciousness. While other conditions may cause a moderate deterioration (e.g., dementia and delirium) or transient interruption (e.g., grand mal and petit mal seizures) of consciousness, they are not included in this category.
Medical experts increasingly view anosognosia as a disorder of consciousness. Anosognosia is a Greek-derived term meaning "unawareness of disease". This is a condition in which patients are disabled in some way, most commonly as a result of a stroke, but either misunderstand the nature of the problem or deny that there is anything wrong with them. The most frequently occurring form is seen in people who have experienced a stroke damaging the parietal lobe in the right hemisphere of the brain, giving rise to a syndrome known as hemispatial neglect, characterized by an inability to direct action or attention toward objects located to the left with respect to their bodies. Patients with hemispatial neglect are often paralyzed on the left side of the body, but sometimes deny being unable to move. When questioned about the obvious problem, the patient may avoid giving a direct answer or an explanation that does not make sense. Patients with hemispatial neglect may also fail to recognize paralyzed parts of their bodies: one frequently mentioned case is of a man who repeatedly tried to throw his own paralyzed right leg out of the bed he was lying in, and when asked what he was doing, complained that somebody had put a dead leg into the bed with him. An even more striking type of anosognosia is Anton–Babinski syndrome, a rarely occurring condition in which patients become blind but claim to be able to see normally, and persist in this claim in spite of all evidence to the contrary.
== Outside human adults ==
=== In children ===