The relationship of injury severity score and Glasgow coma score to rehabilitative potential in patients suffering traumatic brain injury

The predictive utility of the Injury Severity Score (ISS) and Glasgow Coma Score (GCS) in relation to rehabilitative potential and functional outcome in traumatic brain injury (TBI) is untested. The purpose of this study was to define the relationship of ISS and GCS to rehabilitative potential using the functional independence measure (FIM) score. Trauma and inpatient rehabilitation (IR) registries were queried for demographic, disposition, and injury scoring data. FIM scores at admission (A) and discharge (D) were assessed including IR FIM gain (G). Analysis of variance was used to examine the relationship of ISS and GCS to FIM with predictive utility investigated through bivariate analysis. Of 5488 patients admitted to a Level I trauma center (1999-2000) 1437 suffered TBI with 285 (20%) entering IR. Compared with low-ISS patients the high-ISS patients had significantly lower FIM-A and FIM-D, but FIM-G was static. GCS results were similar, excluding FIM-G which was significantly higher for GCS <8 compared with GCS >8. Bivariate analysis revealed no ISS correlation with FIM-G (r = 0.16) and a weak GCS correlation (FIM-G r = -0.15). As prospective predictive measures ISS and GCS correlate weakly with rehabilitative potential in TBI patients. Severely injured patients including those with severe TBI have a rehabilitative gain toward functional independence that is similar to that of when compared with those less severely injured.