levels of consciousness


consciousness

 [kon´shus-nes] 1. the state of being conscious; fully alert, aware, oriented, and responsive to the environment.2. subjective awareness of the aspects of cognitive processing and the content of the mind.3. the current totality of experience of which an individual or group is aware at any time.4. in psychoanalysis, the conscious.5. in Newman's conceptual model, health as expanding consciousness, the informational capacity of the human system, or its capacity for interacting with the environment; consciousness is considered to be coextensive with the universe, residing in all matter.clouding of consciousness see clouding of consciousness.levels of consciousness 1. an early freudian concept referring to the conscious, preconscious, and unconscious.2. the somewhat loosely defined states of awareness of and response to stimuli, generally considered an integral component of the assessment of an individual's neurologic status. Levels of consciousness range from full consciousness (behavioral wakefulness, orientation as to time, place, and person, and a capacity to respond appropriately to stimuli) to deep coma (complete absence of response).
Consciousness depends upon close interaction between the intact cerebral hemispheres and the central gray matter of the upper brainstem. Although the hemispheres contribute most of the specific components of consciousness (memory, intellect, and learned responses to stimuli), there must be arousal or activation of the cerebral cells before they can function. For this reason, it is suggested that a detailed description of the patient's response to specific auditory, visual, and tactile stimuli will be more meaningful to those concerned with neurologic assessment than would the use of such terms as alert, drowsy, stuporous, semiconscious, or other equally subjective labels. Standardized systems, such as the glasgow coma scale, aid in objective and less ambiguous evaluation of levels of consciousness.
Examples of the kinds of stimuli that may be used to determine a patient's responsiveness as a measure of consciousness include calling him by name, producing a sharp noise, giving simple commands, gentle shaking, pinching the biceps, and application of a blood pressure cuff. Responses to stimuli should be reported in specific terms relative to how the patient responded, whether the response was appropriate, and what occurred immediately after the response.

levels of consciousness

States of arousal and awareness, ranging from fully awake and oriented to one's environment to comatose. It is important to use a standardized system of description rather than vague terms such as semiconscious, semicomatose, or semistuporous.

Alert wakefulness: The patient perceives the environment clearly and responds quickly and appropriately to visual, auditory, and other sensory stimuli.

Drowsiness: The patient does not perceive the environment fully and responds to stimuli appropriately but slowly or with delay. He or she may be roused by verbal stimuli but may ignore some of them. The patient is capable of verbal response unless aphasia, aphonia, or anarthria is present. Lethargy and obtundation also describe the drowsy state.

Stupor: The patient is aroused by intense stimuli only. Loud noise may elicit a nonspecific reaction. Motor response and reflex reactions are usually preserved unless the patient is paralyzed.

Coma: The patient does not perceive the environment and intense stimuli produce a rudimentary response if any. The presence of reflex reactions depends on the location of the lesion(s) in the nervous system.

See also: consciousness