Two-factor structure of the Comprehensive Trail-making Test in adults.

Previous evaluation of the Comprehensive Trail-Making Test (CTMT) using a confirmatory factor analysis (CFA) revealed that for children, a two-factor model provided a better fit than did a one-factor model. The purpose of this study was to explore whether these findings suggested a developmental factor structure or if the two-factor structure also would be supported for adults. CFA was conducted using M-plus to examine the factor structure for adults in the standardization sample using all five trails tasks from the CTMT. The findings of the CFA indicated an excellent fit for the two-factor model. In contrast, the one-factor structure (i.e., use of a composite score) was not supported. Results were the same when younger (younger than 50 years of age) and older (50 years old or older) adults were considered separately. These data suggest that a single score may not be a valid representation of executive functioning. The results support a two-factor structure that represents attention/sequencing and set switching/inhibition.