Altered consciousness

Clinic

• Altered level of consciousness is any measure of arousal other than normal.
• Level of consciousness (LOC) is a measurement of a person's arousability and responsiveness to stimuli from the environment.
• A mildly depressed level of consciousness or alertness may be classed as lethargy; someone in this state can be aroused with little difficulty.
• Altered level of consciousness is sometimes described as altered sensorium

Levels of consciousness

Level	Summary (Kruse)	Description
Metaconscious	Preternatural	People who possess the ability to monitor and control their own cognitive processes in addition to meeting all the criteria indicative of a normal level of consciousness. In the field of cognitive neuroscience, metacognitive monitoring and control have been viewed as functions of the prefrontal cortex, which receives sensory input signals from divergent cortical regions and implements control through feedback loops which are established utilizing the underlying mechanisms of neuroplasticity (see chapters by Schwartz & Bacon and Shimamura, in Dunlosky & Bjork, 2008).
Conscious	Normal	Assessment of LOC involves checking orientation: people who are able promptly and spontaneously to state their name, location, and the date or time are said to be oriented to self, place, and time, or "oriented X3". A normal sleep stage from which a person is easily awakened is also considered a normal level of consciousness. "Clouding of consciousness" is a term for a mild alteration of consciousness with alterations in attention and wakefulness.
Confused	Disoriented Impaired thinking and responses	People who do not respond quickly with information about their name, location, and the time are considered "obtuse" or "confused". A confused person may be bewildered, disoriented, and have difficulty following instructions. The person may have slow thinking and possible memory time loss. This could be caused by sleep deprivation, malnutrition, allergies, environmental pollution, drugs (prescription and nonprescription), and infection.
Delirious	Disoriented Restlessness Hallucinations Sometimes delusions	Some scales have "delirious" below this level, in which a person may be restless or agitated and exhibit a marked deficit in attention.
Somnolent	Sleepy	A somnolent person shows excessive drowsiness and responds to stimuli only with incoherent mumbles or disorganized movements.
Obtunded	Decreased alertness Slowed psychomotor responses	In obtundation, a person has a decreased interest in their surroundings, slowed responses, and sleepiness.
Stuporous	Sleep-like state (not unconscious) Little/ No spontaneous activity	People with an even lower level of consciousness, stupor, only respond by grimacing or drawing away from painful stimuli.
Comatose	Cannot be aroused No response to stimuli	Comatose people do not even make this response to stimuli, have no corneal or gag reflex, and they may have no pupillary response to light.

.

Glasgow Coma Scale

• The most commonly used tool for measuring LOC objectively is the Glasgow Coma Scale (GCS).
• Verbal, motor, and eye-opening responses to stimuli are measured, scored, and added into a final score on a scale of 3–15, with a lower score being a more decreased level of consciousness.

Pathophysiology

• Reticular formation is known to play a role in these.
• Reticular formation is a complex network of brainstem nuclei and neurons that serve as a major integration and relay center for many vital brain systems to coordinate functions necessary for survival
• Ascending reticular activating system is a postulated group of neural connections that receives sensory input and projects to the cerebral cortex through the midbrain and thalamus from the reticular formation.

• Normally, stupor and coma are produced by interference with the brain stem
• Mass lesions in the brain stem normally cause coma due to their effects on the reticular formation.