Normative adjustments to the D-KEFS trail making test: corrections for education and vocabulary level

Abstract

The Delis-Kaplan Executive Function System (D-KEFS) Trail Making Test (TMT), a modification of the original TMT, was created to isolate set-shifting (Letter-Number Switching) from other component skills. This was accomplished by including four baseline conditions (Visual Scanning, Number Sequencing, Letter Sequencing, and Motor Speed) and by placing equal numbers of stimuli in the three sequencing conditions. Given that some studies with the original TMT demonstrated a significant effect of education and intellectual functioning on performance, we utilized the D-KEFS national standardization sample to examine the effects of education and vocabulary level-i.e., Vocabulary subtest from the Wechsler Abbreviated Scale of Intelligence (WASI)-on the D-KEFS TMT. The results indicate a significant effect of these variables on each D-KEFS TMT condition. Normative tables for education- and vocabulary-adjusted scaled scores based on the database from the D-KEFS national normative study were generated.