Trail Making Test revisited: Patterns of visual and manual trajectories as markers of executive processes.

LINARI I; JUANTORENA G; PETRONI; KAMIENKOWSKI JE

Congreso; XXXIV Reunión Anual de la Sociedad Argentina de Neurociencia; 2019

The Trail Making Test (TMT) is a neuropsychological test widely used for decades for the diagnosis of executive dysfunctions in a set of neurological and psychiatric conditions. The TMT has two parts: A) participants have to connect 20 consecutive numbers and B) both numbers and letters are connected in an alternate order (1-A-2-B, etc). It is a complex task, and involves different stages supported by distinct executive functions. Surprisingly, it is done with paper and pencil, and only the total time is quantified. We designed a computer version of the TMT in order to study, with more resolution and precision, the components of the task in healthy participants and patients, providing a deeper understanding of the underlying processes involved in performing a traditional test. We measured both hand and gaze position. We found that total time (part B vs A) is similar to the traditional version. Concerning eye movements, saccades are similar in A and B, but there are fewer fixations in A. Moreover, we found a longer lag between gaze and hand in B, explained by a delay in the outgoing hand movements but not in the gaze. Using both hand and eye movements we are able to parse the whole task into different stages, opening the possibility of exploring them in terms of different executive functions. Finally, a standardized evaluation of executive functions was collected to validate the digital TMT measures.