The Glasgow coma scale is a test for assessing the level of conscious awareness in a patient. The test was proposed in 1974 by Graham Teasdale and Bryan Jennett, and is the most widely used consciousness level scale. The scale uses specific indicators of eye movement, verbal responses and the ability to comprehend and carry out simple motor tasks.
Source: GCS Website, retrieved April 4, 2017: http://www.glasgowcomascale.org/what-is-gcs/