Conceptual Structure of Health-Related Quality of Life for Persons With Traumatic Brain Injury: Confirmatory Factor Analysis of the TBI-QOL

Objective: To determine the factor structure of the Traumatic Brain Injury-Quality of Life (TBI-QOL) measurement system.

Design: Observational.

Setting: 3 TBI Model Systems rehabilitation centers.

Participants: Twenty TBI-QOL item banks were administered to a sample of community-dwelling adults with TBI (N=504) as part of a study of TBI classification. A subsample of participants (n=200) was randomly selected for exploratory factor analyses, while data from the remaining participants (n=304) were used for the confirmatory factor analysis. To examine a wide range of conceptual models, confirmatory factor analyses were conducted on a total of 16 models, ranging from 1 to 7 factors.

Interventions: Not applicable.

Main outcome measures: Not applicable.

Results: Initial exploratory factor analysis yielded support for a 5-factor model (negative emotion, cognitive impairment, functioning and participation, positive emotion, pain). Confirmatory factor analysis results, however, indicated a 7-factor model including physical function, physical symptoms, cognition, negative emotion, positive emotion, sense of self, and social participation (model 16; robust fit statistics root mean square error of approximation =.063, standardized root mean square residual =.035, comparative fit index =.955, Tucker-Lewis Index =.943, Bayes Information Criterion =40059.44).

Conclusions: The complex 7-factor model of the TBI-QOL provides a more nuanced framework for understanding health-related quality of life for persons with TBI than the commonly used 3-factor model including physical health, mental health, and social health.