Multimodal immersive trail making-virtual reality paradigm to study cognitive-motor interactions

Neuropsychological tests of executive function have limited real-world predictive and functional relevance. An emerging solution for this limitation is to adapt the tests for implementation in virtual reality (VR). We thus developed two VR-based versions of the classic Color-Trails Test (CTT), a well-validated pencil-and-paper executive function test assessing sustained (Trails A) and divided (Trails B) attention-one for a large-scale VR system (DOME-CTT) and the other for a portable head-mount display VR system (HMD-CTT). We then evaluated construct validity, test-retest reliability, and age-related discriminant validity of the VR-based versions and explored effects on motor function.

Healthy adults (n = 147) in three age groups (young: n = 50; middle-aged: n = 80; older: n = 17) participated. All participants were administered the original CTT, some completing the DOME-CTT (14 young, 29 middle-aged) and the rest completing the HMD-CTT. Primary outcomes were Trails A and B completion times (t_A, t_B). Spatiotemporal characteristics of upper-limb reaching movements during VR test performance were reconstructed from motion capture data. Statistics included correlations and repeated measures analysis of variance.

Construct validity was substantiated by moderate correlations between the'gold standard' pencil-and-paper CTT and the VR adaptations (DOME-CTT: t_A 0.58, t_B 0.71; HMD-CTT: t_A 0.62, t_B 0.69). VR versions showed relatively high test-retest reliability (intraclass correlation; VR: t_A 0.60-0.75, t_B 0.59-0.89; original: t_A 0.75-0.85, t_B 0.77-0.80) and discriminant validity (area under the curve; VR: t_A 0.70-0.92, t_B 0.71-0.92; original: t_A 0.73-0.95, t_B 0.77-0.95). VR completion times were longer than for the original pencil-and-paper test; completion times were longer with advanced age. Compared with Trails A, Trails B target-to-target VR hand trajectories were characterized by delayed, more erratic acceleration and deceleration, consistent with the greater executive function demands of divided vs. sustained attention; acceleration onset later for older participants.

The present study demonstrates the feasibility and validity of converting a neuropsychological test from two-dimensional pencil-and-paper to three-dimensional VR-based format while preserving core neuropsychological task features. Findings on the spatiotemporal morphology of motor planning/execution during the cognitive tasks may lead to multimodal analysis methods that enrich the ecological validity of VR-based neuropsychological testing, representing a novel paradigm for studying cognitive-motor interactions.