Trail Making Test in assessing children with reading disabilities: a test of executive functions or content information.

The speed of performance on Part A, Part B, and on an experimental version containing alphabetical series (Part A Alphabetic) of the Trail Making Test was studied with 19 children with reading disabilities and 34 controls from Grades 4 to 6. When the test was used in discriminant profile fashion, children with reading disabilities showed a deficit compared with control children on Part B relative to part A but did not relative to the new Part A Alphabetic. The results indicate that the performance of the children with reading disabilities on Part B is likely to be affected by their slowness on the alphabetical series. Based on these results we recommend that the speed of following the alphabetical series be assessed when using Part B of the Trail Making Test.