19 April 2009

Levels of consciousness (and no, I'm not Deepak Chopra)

Odd as it is to measure something like consciousness, it is a must to determine a possible medical condition, and the levels must be precise to give an accurate status before and after treatment (1). A state of consciousness can indicate a person’s wakefulness, awareness and alertness (2). Consciousness may “lower” a level or more depending on a range of factors that include alcohol or barbiturate overdose, stroke, epilepsy, bacterial meningitis, diabetes, kidney failure or heart disease (1).

Example of consciousness terminology (1):
  • Normal consciousness is characterized by a fully responsive, self-awareness and awareness of surroundings
  • Inattention is when a patient finds it difficult to identify and attend revelant stimuli
  • Confusion happens when thinking is slower or less clear; or when a patient is distracted
  • Clouding (obtundation) is when inattention and confusion are more profound; rousing is more difficult
  • Stupor is physical and mental activity at its minimum (kind of like me in the morning); you have to use persistent and vigorous stimulation to arouse them
  • Coma is when a patient simply can’t be aroused, but might produce a pattern of behavior if stimulus is intense

Many clinical methods of have been used to determine the conscious state. The Glasgow Coma Scale, introduced in 1974 (2), has been functional in many hospitals including Grady Memorial Hospital in Atlanta, Georgia, for 30 years (3). The scale is easy to use using eye, verbal and motor responses (1;3). But it does have many limitations because there is a tendency to skew scores depending on experience of examiners and their paradigms (2). New techniques for determining consciousness may come in the future. They may include new terminology and new scales (2;3).

Reference List

1. Nowak TJ, Handford AG. Pathophysiology: Concepts and Applications for Health Professionals. New York: McGraw-Hill, 2004.
2. Matis G, Birbilis T. The Glasgow Coma Scale--a brief review. Past, present, future. Acta Neurol Belg 2008;108:75-89.
3. Tindall S. 1990. Levels of Consciousness. Clinical Methods: The History, Physical, and Laboratory Examinations. Available at: http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm&part=A1731

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