Latent structure of the Postconcussion Syndrome Questionnaire.

The underlying structure of the Postconcussion Syndrome Questionnaire (PCS) was evaluated in a large sample of medical and psychiatric patients. Three potentially viable models were generated using exploratory factor analysis with half of the sample. The other half evaluated the 3-, 4-, and 5-factor models using confirmatory factor analytic procedures. The factor analyses generated compelling data for a 5-factor model for the PCS questionnaire. However, internal consistency for each of the factors argued in favor of the 3-factor model. Balancing internal consistency, confirmatory factor analyses, and parsimony resulted in endorsement of a 4-factor solution for the PCS questionnaire for this sample. The factors are best described as clusters of psychological, somatic, cognitive, and infrequent complaints.