Parkinson's patients delay fixations when circumventing an obstacle and performing a dual cognitive task

Towards a comprehensive framework for complex walking tasks: Characterization, behavioral adaptations, and clinical implications in ageing and neurological populations

Complex walking tasks, including change of direction, patterns and rhythms, require more attentional resources than simple walking and significantly impact walking performance, especially among ageing and neurological populations. More studies have been focusing on complex walking situations, with or without the addition of cognitive tasks, creating a multitude of walking situations. Given the lack of a clear and extensive definition of complex walking, this narrative review aims to identify and more precisely characterize situations and related tests, improve understanding of behavioral adaptations in ageing and neurological populations, and report the clinical applications of complex walking. Based on the studies collected, we are proposing a framework that categorizes the different forms of complex walking, considering whether a cognitive task is added or not, as well as the number of distinct objectives within a given situation. We observed that combining complex walking tasks with a cognitive assignment places even greater strain on attentional resources, resulting in a more pronounced decline in walking and/or cognitive performance. This work highlights the relevance of complex walking as a simple tool for early detection of cognitive impairments and risk of falls, and its potential value in cognitive-motor rehabilitation. Future studies should explore various complex walking tasks in ageing and neurological populations, under varied conditions in real-life or in extended virtual environments.

Dual tasking reduces gait asymmetry of trajectory deviation during obstacle circumvention in people with Parkinson's disease

BACKGROUND

Certain aspects of gait may depend on cognition, and the effects of dual-tasking (DT) on gait asymmetry (GA) during obstacle circumvention in people with Parkinson's disease (pwPD) may be walking phase-dependent. While the approaching phase requires allocating significant cognitive resources to perform the task, outweighing the available resources may increase GA. During the avoiding phase, the obstacle could be used as an external cue, enhancing the attention to the obstacle and, consequently, improving gait control and regulating GA.

OBJECTIVE

The study investigated the effects of obstacle circumvention during gait with DT on GA in pwPD, considering the circumvention phase.

METHODS

Thirty participants, 15 pwPD and 15 neurologically healthy individuals, circumvented an obstacle 20 times (in total) according to side (right and left side) and DT (presence and absence). Spatial-temporal stride parameters, medial-lateral and horizontal trajectory deviations from the original path, strategy to obstacle circumvention (lead limb away from or close to the obstacle during the crossing step), and gaze parameters were calculated during the approaching and avoiding phases. The parameters were grouped considering the side that the obstacle was circumvented during each task, and the symmetry index was calculated.

RESULTS

The results showed greater asymmetry of time of fixations, width, duration, and velocity during the approaching phase (p < 0.02), whereas the avoiding phase decreased asymmetry of medial-lateral and horizontal trajectory deviations parameters (p < 0.001) during obstacle circumvention with DT, in both pwPD and control group.

CONCLUSIONS

The findings offer a basis for considering that goal-directed movement control may regulate GA in pwPD.

Measuring implicit sequence learning and dual task ability in mild to moderate Parkinson´s disease: A feasibility study

We investigated the feasibility aspects of two choice reaction time tasks designed to assess implicit sequence learning and dual task ability in individuals with mild to moderate Parkinson’s disease in comparison to healthy individuals. Twelve individuals with mild to moderate Parkinson’s disease and 12 healthy individuals, all ≥ 60 years of age, were included. A serial reaction time task was used as a measure of implicit sequence learning and a similar task but with the addition of a simple counting task, was used as a measure of dual task ability. We have present thorough descriptive statistics of the data but we have refrained from any inferential statistics due to the small sample size. All participants understood the task instructions and the difficulty level of both tasks was deemed acceptable. There were indications of task fatigue that demand careful choices for how best to analyse the data from such tasks in future trials. Ceiling effects were present in several accuracy outcomes, but not in the reaction time outcomes. Overall, we found both tasks to be feasible to use in samples of individuals with mild to moderate Parkinson’s disease and healthy older individuals.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.