Prediction of functional outcomes after traumatic brain injury: a comparison of 2 measures of duration of unconsciousness

Abstract

Objective: To compare the usefulness of time until motor localization occurs versus time until commands are followed in predicting outcome after traumatic brain injury (TBI).

Design: A retrospective analysis of data from a prospective cohort study of subjects with severe TBI.

Setting: Seventeen Traumatic Brain Injury Model System programs.

Participants: A total of 496 subjects, recruited through the TBI Model System programs, with loss of consciousness greater than 1 day, with no late neurosurgical complications, and complete data for all measures.

Interventions: Not applicable.

Main outcome measures: Time until Glasgow Coma Scale (GCS) motor score of 5 (time to motor localization) and time until GCS motor score of 6 (time until commands were followed) were abstracted from medical records. Functional outcomes were assessed at inpatient rehabilitation admission and discharge, along with acute and rehabilitation lengths of stay and charges.

Results: Time until commands were followed was a better predictor of all of the outcomes assessed than time until motor localization occurred. In multiple regression models, time until motor localization did not add significantly to the prediction provided by time until commands were followed. The predictive power of time to command following was superior even in the subgroup with poor language comprehension as measured by the Token Test.

Conclusion: Despite the theoretical appeal of time to motor localization (eg, in persons with language comprehension problems), time to command following appears to be a more powerful predictor of outcome after severe brain injury.