Examining interference of different cognitive tasks on voluntary balance control in aging and stroke

Abstract

This study compared the effect of semantic and working memory tasks when each was concurrently performed with a voluntary balance task to evaluate the differences in the resulting cognitive-motor interference (CMI) between healthy aging and aging with stroke. Older stroke survivors (n = 10), older healthy (n = 10) and young adults (n = 10) performed the limits of stability, balance test under single task (ST) and dual task (DT) with two different cognitive tasks, word list generation (WLG) and counting backwards (CB). Cognitive ability was evaluated by recording the number of words and digits counted while sitting (ST) and during balance tasks (DT). The balance and cognitive costs were computed using [(ST-DT)/ST] × 100 for all the variables. Across groups, the balance cost was significantly higher for the older stroke survivors group in the CB condition than older healthy (p < 0.05) and young adult groups (p < 0.05) but was similar between these two groups for the WLG task. Similarly, the cognitive cost was significantly higher in older stroke survivors than in older healthy (p < 0.05) and young adults (p < 0.01) for both the cognitive tasks. The working memory task resulted in greater CMI than the semantic one, and this difference seemed to be most apparent in older stroke survivors. Young adults showed the least CMI, with a similar performance on the two memory tasks. On the other hand, healthy aging and stroke impact both semantic and working memory. Stroke-related cognitive deficits may further significantly decrease working memory function.

Attentional Demands of Locomotor and Balance Tasks in Individuals Aging with and without a Stroke

“…Considering reduced central capacity with aging alongside declining neuromuscular function could possibly limit greater allocation of attentional resources to motor tasks, contributing to higher motor costs as seen in our study [26]. Unlike young adults, age-matched adults prioritized the motor task only during the LOS task ( Figure 3f) as seen in previous studies [27]. They were unable to do so during the RB task, which in fact posed higher threat to balance than the LOS task.…”

“…This may explain a higher motor cost for the voluntary, LOS task in stroke survivors as compared with the age-matched controls despite implicit prioritization of the motor task (see figure 3i) [27]. Considering that the stroke survivors in this study were in chronic phase of recovery (at least 3 years post stroke), it may be difficult to conclude that the CMI observed in this population may be directly due the stroke-related pathology [5].…”

“…Healthy young adults (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) years, N = 36), community dwelling chronic stroke survivors (50-70 years, N =36) and age-matched healthy adults (50-70 years, N = 36) participated in the study. The information about type of stroke was obtained from subjects' physicians.…”

No role of working memory in the relation between mental rotation and postural stability

“…Furthermore, many dual-task studies address the relationship between working memory and postural stability. In addition to some findings linking different areas of working memory and postural stability (Shumway-Cook and Woollacott, 2007;Bhatt et al, 2016;Fujita et al, 2016), the connection between the visuospatial sketchpad and postural stability is of particular interest in the context of this study. Here, tasks involving the visuospatial sketchpad were shown to have higher postural-cognitive dual-task costs in older subjects (Maylor and Wing, 1996).…”

How increased cognitive load affects the dual-task cost in healthy young adults? A randomized, double-blind sham-controlled study

“…Generally, the result of these studies indicates that cognitive ability and balance are complementary and inseparable, and proper balance maintenance cannot be considered a purely automated sensorimotor activity 41,[46][47][48][49][50] . The importance of cognitive-motor interference is more evident in daily life activities, mainly when we perform multiple concurrent tasks, such as talking while walking, drinking while driving, cutting something while talking, etc.…”