Visuospatial working memory and obstacle crossing in young and older people

Abstract

Obstacle crossing requires visuospatial working memory to guide the trailing leg trajectory when vision in unavailable. Visuospatial working memory, as assessed with neuropsychological tests, declines with age, however, this remains to be investigated functionally in obstacle crossing. There is also evidence that visuospatial encoding during a secondary task interferes with balance control during stepping and walking in older people. Here, we studied the interaction effects of age by delay (study 1) and age by secondary visuospatial task (study 2) conditions on obstacle clearance in a visuospatial working memory -guided obstacle crossing task. Healthy young adults aged 19 to 36 years (n = 20 in study 1 and n = 17 in study 2) and healthy older adults aged 66 to 83 years (n = 29 in study 1 and n = 21 in study 2) were instructed to step over an obstacle with their leading leg and straddle it for a delay period before completing the crossing with their trailing leg. In study 1, two obstacle height conditions (12 cm, 18 cm) and two delay durations (20 s, 60 s) were presented in random order. In study 2, participants were required to attend to either no secondary task (control), a visuospatial secondary (star movement) task, or a nonspatial secondary (arithmetic) task, while straddling the obstacle for a delay duration of 20 s, at obstacle heights of 12 cm and 18 cm, randomly presented. Trailing leg kinematics (mean and variability of maximum toe clearance over the obstacle) were determined via motion capture. There were no statistically significant age by delay or age by secondary task interactions. In study 1, toe clearance variability was significantly greater in young adults and increased with increasing delay duration in both groups. In study 2, compared with the control condition, toe clearance variability was significantly greater in the non-spatial secondary task condition but not in the visuospatial condition. Contrary to our hypotheses, these findings suggest that young and older adults alike can store an obstacle representation via visuospatial working memory for durations of at least 60 s and use this information to safely scale their trailing leg over an obstacle. However, the increase in trailing leg toe clearance variability with delay duration suggests that obstacle representation starts to deteriorate even within the first 20 s regardless of age. The finding that undertaking a concurrent arithmetic task impaired visuospatial working memory-guided obstacle clearance suggests a potential increased risk of tripping during obstacle crossing while dual-tasking in both young and older people.

The effect of visual sensory interference during multitask obstacle crossing in younger and older adults

“…We based this hypothesis on the longer reaction times observed during multitasking in older adults from previous research (e.g., [25,53]). However, we note that a recent publication regarding multitask obstacle crossing also demonstrated no age-related main or interaction effects [8]. Similarly, our findings indicate that the impairing effect of gaze diversion on RT, with a simple, visual RT task, was independent of age.…”

“…Multitask performance can provide a window into the mechanisms underlying age-related impairments that lead to falls [ 7 ]. For example, while visuospatial working memory (VSWM) is an important component for obstacle crossing, older adults’ ability to store and use an obstacle representation via VSWM is not different from younger adults [ 8 ], indicating that mechanisms other than VSWM are responsible for the age-related impairments in locomotor multitasks.…”

Graph Theory Further Revealed Visual Spatial Working Memory Impairment in Patients with Inflammatory Bowel Disease

“…11 Visuospatial working memory (VSWM) involves the retention and manipulation of spatial information within a brief timeframe, requiring intricate cooperation among various brain regions. 12,13 The mental rotation task (MRT) is commonly used in psychology to assess visuospatial working memory function, widely used to test visuospatial cognitive impairment. 10 Despite abnormal cognitive performance in IBD patients and compromised visual networks, 14,15 our understanding of VSWM deficits in IBD remains incomplete.…”