The FOUR score has 4 components: eye responses, motor responses, brainstem reflexes, and respiration pattern. It was developed by neurointensivists at the Mayo Clinic as an alternative to the Glasgow Coma Scale (GCS), in an attempt to improve on inter-observer reliability. A full text version of the original article from 2005 by Wijdicks et al presenting the scale can be read here. The most comprehensive publication assessing its validity is that of Iyer et al from 2009. They looked at its reliability in an ICU population and concluded that it has significant advantages over GCS. A similar conclusion was also reached in an article by Jalali and colleagues published in 2014. However, it has so far failed to catch on as the assessment score of choice among most clinicians.

“FOUR” in this context is an acronym for “Full Outline of UnResponsiveness.” It comprises a 17-point scale (with potential scores ranging from 0 to 16).