Functional outcome scales in traumatic brain injury: a comparison of the Glasgow Outcome Scale (Extended) and the Functional Status Examination

Abstract

Clinical trials aimed at developing therapies for traumatic brain injury (TBI) require outcome measures that are reliable, validated, and easily administered. The most widely used of these measures, the Glasgow Outcome Scale (GOS) and the GOS-Extended (GOS-E), have been criticized as suffering from ceiling effects. In an attempt to develop a more useful and dynamic outcome measure, the Functional Status Examination (FSE) was developed, which grades outcome across 10 functional domains. The FSE has been demonstrated to be reliable and sensitive in monitoring recovery after TBI. This manuscript compares FSE with GOS-E in a cohort of patients with a wide range of injury severities. 177 individuals who survived at least 6 months after TBI were studied. The FSE and GOS-E were administered 6-12 months after injury. FSE and GOS-E scores correlated well with each other. FSE scores were distributed throughout the range, indicating that ceiling and floor effects were not present. Physiologic measures of injury severity (Glasgow Coma Score [GCS]) did not correlate with anatomic measures (Abbreviated Injury Scale [AIS] and Injury Severity Score [ISS]). GCS correlated weakly with both outcome measures, but AIS/ISS did not. We conclude that FSE and GOS-E are reliable outcome measures for TBI survivors, and FSE may offer some advantages over GOS-E due its ability to provide a more detailed description of deficits. The majority of the variance in outcome is not accounted for by currently available measures of injury severity.