Assessing the information processing demand of functional task performance using voice reaction time in young, middle-age, and elderly adults

Efficient information processing is essential to successful task performance. With aging, a decline in the ability to acquire, cognitively process, and act on environmental and somatosensory information occurs. The purpose of this study was to examine the effects of aging and task complexity on information processing speed in three groups of adults who performed four well-learned functional tasks. Using a dual-task paradigm, voice reaction time (VRT) to an auditory stimulus was measured while young (n = 24, mean age = 24.55 ± 1.94 yrs), middle-age (n = 24, mean age = 45.70 ± 3.22 yrs), and elderly (n = 24, mean age = 72.74 ± 3.92 yrs) adults sat in a chair, stood, walked on a level surface, and walked toward and stepped up onto a curb. A three (group) by five (task condition) ANOVA with repeated measures on the last factor was used to examine changes in VRT. Significant main effects for group (p < 0.001), task condition (p < 0.001), and the interaction of group with task (p < 0.001) were found. No significant between or within group differences in sitting and standing VRT were found. A significant within group increase in VRT was found for the three groups when comparing either sitting or standing to walking on a level surface and walking toward and stepping up onto the curb. Between group differences also revealed that elderly adults had significantly longer VRTs when compared to the young and middle-age adult groups for each of the walking tasks. VRT, which is an indicator of task-specific information processing demand, was not significantly different for the young, middle-age, and elderly adults during the sitting and standing tasks. Under conditions of low task complexity, elderly adults had the capacity to process information as fast as the other two groups. Significant between group differences became apparent during the walking tasks, indicating that the elderly adult group was more affected by the walking tasks. Significant within group differences indicated that walking also increased the information processing demand being placed on the young and middle-age adult groups. Based on group-specific and task-specific changes in VRT, support is provided for the premise that participation in familiar and well-learned functional tasks has an associated information processing cost. Elderly adults are affected more by task complexity than their younger counterparts.