Trail Making Test errors in normal aging, mild cognitive impairment, and dementia.

The objective of the present study was to provide normative data for Trail Making Test (TMT) time to completion and performance errors among cognitively normal older adults, and to examine TMT error rates in conjunction with time scores for pre-clinical and clinical Alzheimer's disease (AD) diagnostic decision-making. A sample of 526 individuals was classified into three diagnostic groups (normal controls, N=269; mild cognitive impairment, MCI, N=200; AD, N=57) by a multidisciplinary consensus conference. Results indicated that performance differed among the three groups for TMT A and B time scores as well as TMT B error rate. Diagnostic classification accuracy (i.e., sensitivity, specificity, and positive and negative predictive powers) is described for various combinations of the diagnostic groups. The findings show that TMT B time and errors are independently meaningful scores, and both therefore have clinical utility in assessing individuals referred for dementia evaluations.