The factor structure of the Disability Rating Scale in individuals with traumatic brain injury.

PURPOSE: To examine the factor structure of the Disability Rating Scale and the predictive validity of the scale's factors among individuals with traumatic brain injury.

MATERIALS AND METHODS: Five hundred and eight individuals with moderate-to-severe traumatic brain injury were administered the Disability Rating Scale. The sample was randomly divided into two groups. An exploratory factor analysis was conducted on Group 1, and a confirmatory factor analysis on Group 2. Regressions were performed to determine the predictive ability of the factors.

RESULTS: The exploratory factor analysis generated a three-factor structure, explaining 82.1% of the variance. Factor 1, comprising three disability items (feeding, toileting, and grooming), accounted for 58.4% of the variance. Factor 2, comprising three impairment items (eye opening, communication ability, and motor response), accounted for 14.8% of the variance. Factor 3, comprising two handicap items (level of functioning and employability), accounted for 8.9% of the variance. The three-factor solution was confirmed by confirmatory factor analysis. Regressions revealed the impairment factor at admission and the disability factor at discharge accounted for unique variance in predicting functional outcomes at one year post-injury.

CONCLUSION: Each factor of the Disability Rating Scale may independently serve as a clinically useful outcome predictor after traumatic brain injury. Implications for rehabilitation The Disability Rating Scale is a measure used in brain injury rehabilitation that generates a total score indicating level of disability. This study confirmed a three-factor structure and showed that the individual factor scores provide unique information in predicting rehabilitation outcomes at one year post-injury.