Tracking the norms: A regression-based approach to trail making test performance in the Turkish population

Objective: The Trail Making Test (TMT) is a widely used neuropsychological tool for assessing executive functions. This study aimed to establish regression-based normative data for TMT performance in a Turkish population aged 18-80, accounting for the effects of age, education, and sex on both basic (TMT A and TMT B) and derived scores (TMT B-A and TMT B/A). Method: A total of 462 participants were recruited, with 409 included in the final analysis after applying exclusion criteria. Participants completed the international version of the TMT. Pearson correlation analyses and multiple linear regression models assessed relationships between TMT scores and demographic variables. Education was treated as a continuous variable, and regression-based norms were developed for all TMT scores. Results: Age and education were significant predictors of TMT performance. Age primarily affected TMT A scores, while education was the strongest predictor for TMT B, TMT B-A, and TMT B/A scores. The regression models explained 36-38% of the variance in basic scores and 6-24% in derived scores. Women performed better than men on the TMT B/A ratio score, but overall, sex had a less pronounced effect than age and education. Conclusions: This study provides the first regression-based normative data for the TMT in a Turkish population. These norms are crucial for improving the accuracy of neuropsychological assessments in Turkey and facilitating cross-cultural comparisons in cognitive research. The findings emphasize the importance of adjusting for demographic factors in clinical and research settings to ensure precise evaluations of cognitive functioning.