INTERMANUAL AND ALTERNATE-FORM EQUIVALENCE ON THE TRAIL MAKING TESTS

Intermanual discrepancies in performance and alternate-form equivalenc e on the Trail Making Test were examined among 40 left- and 40 right-h and-preferred normal adults (N = 80). The findings indicate that admin istration of the Trail Making Tests to the nonpreferred hand does not result in a clinically meaningful difference in score. Neither hand pr eference nor task complexity (numeric or numeric/lexical) significantl y affected the magnitude of the intermanual discrepancy. Mixed-model a nalyses of variance revealed an interaction (p < .001) indicating that the alternate form for the numeric/lexical Trail Making Test (Trail M aking Test, Part D; TMT-D) is slightly more difficult than is the orig inal form Trail Making Test, Part B (TMT-B). Therefore, individuals ex posed first to TMT-D performed relatively better in the second trial, whereas individuals exposed first to TMT-B first produced equivalent s cores when presented the more difficult form (TMT-D) on the second tri al. Thus, although TMT-D is not an equivalent form to TMT-B, it may se rve as an excellent alternate form at retest.