Loss of Consciousness Not Required For Concussion Finding

Prolonged Loss of Consciousness A Factor In Concussion Management

"Traditionally, LOC [loss of consciousness] has featured prominently in published concussion severity scales as being associated with more severe injuries."1 Any LOC, however brief, resulted in the concussion being classified as a Grade 3 (severe) concussion.

Recent studies on concussion in sport, however, have consistently demonstrated that brief (less than 1 minute) LOC does not reflect injury severity or predict time to recovery. 

The results of a large-scale study of prolonged (7 or more days) recovery in NFL players demonstrated that prolonged LOC (greater than 1 minute) was associated with prolonged return to play.

As a result, the most recent consensus of sports concussion experts2 is that prolonged LOC (e.g. greater than one minute duration) provides preliminary evidence for caution so that it is listed as one of the "modifying" factors that may influence management of such concussions.

1.Makdissi, M. Is the simple versus complex classification of concussion a valid and useful differentiation? Br. J. Sports Med. 2009; 43;123-127
2. Consensus Statement on Concussion in Sport: the 3rd International Conference on Concussion in Sport held in Zurich, November 2008.

Revised June 22, 2009