Iranian Normative Data for the Trail-Making Test Stratified by Age, Gender, and Education

Purpose: Executive functions and attention are often impaired in neurological, medical, and psychiatric disorders. This study aimed to, in addition to collecting Iranian normative data, examine whether the demographic variables are associated with performance in one of the most widely used neuropsychological tools to measure cognitive status. Materials and Methods: The present study as part of the Iranian Brain Imaging Database project was conducted on 300 healthy individuals in the age range of 20 to 70 years, with an equal number of participants and an equal proportion of genders in each age decade. Independent and dependent variables, respectively, were age (classified by five decades including 20-30-year-olds, 31-40-year-olds, 41-50-year-olds, 51-60-year-olds, and 61-70-year-olds) and performance in the Trail Making Test (TMT; defined in terms of two scores of the completion time of TMT-A and TMT-B). Results: According to correlation coefficients, age and education had a significant negative and positive correlation with both TMT-A and TMT-B (p=0.01), respectively; however, no significant correlation was observed between gender and scores (p 0.05). According to multivariate analysis of variance, the interaction of age, gender, and education did not lead to a significant difference in the TMT scores (p=0.309). In addition, Tukey s post hoc test showed that participants under 40 took significantly less time to complete TMT-A than those over 50, while in TMT-B, participants under 30 years completed in a shorter time than those over 30 years old (p 0.01). Conclusion: Our findings indicate that age and education have a significant association with the performance of the Iranian healthy population in the well-known measure of executive function and attention, and it is necessary to interpret TMT scores using regional normative data in clinical and research settings.