Cognitive sequelae of severe head injury in relation to the Glasgow Outcome Scale.

Aspects of reliability and validity of the Glasgow Outcome Scale were studied by examining outcome scale categories and cognitive test scores in 57 patients with severe closed head injury seen within 2 years of injury. Inter-rater reliability of a three and six point scale was high. The three point scale, unlike the six point, showed a significant statistical association with cognitive test scores. The relationship between test score and outcome category was accurate within the first 3 months of injury, but considerably less so thereafter.