It is common perception that alcohol intoxication lowers the Glasgow Coma Scale (GCS) rating in cases of traumatic brain injury, and is therefore not a reliable rating for intoxicated patients.
In a large study of nearly 500 TBI patients, however, no association was found between alcohol intoxication and GCS score. Only when controlling for injury severity did very high intoxication levels and positive intracranial CT scans correlate with lower GCS scores.
The implication of this research is that GCS scores should be taken at face value when evaluating a patient's injury severity. The perception that GCS scores are lowered by alcohol intoxication is very likely a false one, and may hinder critical and acute care management decisions for TBI patients.
Lange RT, Iverson GL, Brunacher JR, & Franzen MD. Effect of blood alcohol level on Glasgow Coma Scale scores following traumatic brain injury. Brain Injury. (July 2010).