Analysis of errors on the Trail Making Test

This study was designed to determine whether the number and/or types of errors on the Trail Making Test differentiated head-injured and normal control subjects. Errors on Part B were categorized into two types of shifting errors (from number to letter and from letter to number) and two types of sequencing errors (number and letter). Subjects consisted of 133 head-injured patients and 145 normal controls. Analysis showed that the frequency of errors on Parts A and B did not differ significantly between the groups nor did the percentage of subjects making errors. Total shifting and sequencing errors also did not differentiate between the two groups. Although head-injured subjects were more likely than controls to err in shifting from letters to numbers, this finding was of no apparent clinical usefulness. The discriminative value of time scores was confirmed.