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

Abstract

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 (IBID) was implemented on three hundred medically and cognitively healthy people aged 20 to 70. Each decade consisted of 60 participants and the gender proportion was equal in each decade. Five decades of age (20 to 70 years old) and scores obtained in the Trail Making Test (TMT; defined in terms of two scores of the completion time of its two parts A and B) were the independent and dependent variables, respectively. Results: According to correlation coefficients, age and education had a significant negative and positive association with both parts A and B (p=0.01), respectively, with no significant association between gender and TMT 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). 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 normative data gathered in regional settings.