Characterizing the Impact of Baseline Cognitive Status on Dual Task Performance: An Analysis of Postural and Cognitive Outcomes While Backward Protective Stepping

INTRODUCTION: As people age, they become increasingly susceptible to falls, particularly when their attention is divided. Cognitive domains such as executive functioning and processing speed also decline over time and are associated with falls. A critical aspect to reducing falls are reactive steps, which are used to recover balance after a perturbation. Characterizing the relationship between cognition, dual tasking, and prioritization is necessary in order to decrease fall risk in older adults. Thus, the purpose of this analysis was to determine the effects of baseline cognitive status on dual task interference and prioritization of postural and cognitive tasks while reactive stepping. METHODS: 30 participants (Parkinson's disease (PD) n=16, healthy controls (HC) n=14) were divided into two groups based on their baseline cognitive status: the high-cog group (n=18) or the low-cog group (n=12). All participants experienced 7 perturbation trials where they were solely tasked with reactive stepping, 2 cognitive trials where they were solely tasked with verbally responding to an auditory Stroop test, and 7 trials that combined the two tasks. Cognitive and protective stepping performance was calculated for dual task interference and prioritization across groups. RESULTS: There were no outcome variables that showed the log-cog group performing worse than the high-cog group from single to dual task conditions. While examining the dual task interference between groups, the only significant outcome was that the low-cog group exhibited a subtle improvement in their step length performance under dual task conditions while the high-cog group did not. When comparing the prioritization scores, there was no statistically significant difference in prioritization between the high-cog and low-cog group. Albeit not significant across groups, the prioritization score for all outcomes was negative, indicating a stepping prioritization under dual task conditions for both groups. This analysis provides preliminary evidence that baseline cognitive status does not significantly affect dual task interference nor prioritization while reactive step dual tasking. While these effects should be treated with caution, these results would suggest that baseline cognitive status may not play a critical role in dual task interference or attentional allocation in both people with PD and healthy older adults.