SAN2020

The Trail Making Test (TMT) is a widely used neuropsychological test for the diagnosis of executive dysfunctions in a range of clinical conditions. It has two parts, in which participants must connect 20 consecutive numbers (TMT-A) or both numbers and letters in alternating order (TMT-B; 1-A-2-B, etc.). TMT is a complex task and involves several stages supported by different executive functions. It is usually done with paper and pencil and only the total time is quantified, which does not allow a detailed analysis. Here, we designed a digital version where hand and eye positions were measured. This allows us to study with improved precision the components of the task in neurotypical participants. We show that the overall performance is similar to the traditional version, and that it correlates with a general executive functions assessment (IFS). Moreover, eye movements are similar in both parts, but there are fewer fixations in A, which is compatible with a faster resolution. In particular, there are fewer fixations in the initial exploration and planning phases during the task in A. Accordingly, it was observed a longer delay in the outgoing movements of the hand in B, but not in the eye. Finally, the number of items remembered in each step correlates with a better resolution of the task. These results pave the way for a detailed analysis of complex tasks such as TMT, providing a deeper understanding of the processes underlying the resolution of traditional tests.