Research shows that cognitively healthy older adults with mild executive function (EF) weaknesses are vulnerable to the negative impacts of life complexity (or daily busyness) when performing instrumental activities of daily living (IADLs). However, past research assessed life complexity only at one timepoint, not capturing daily fluctuations. Importantly, fluctuations in busyness can themselves have deleterious impacts on functioning. This study extended past research by examining whether (1) variability in daily busyness would be more detrimental than level of busyness to performance of IADLs, and (2) EF assessed at home would moderate deleterious impact of busyness on IADLs.

Fifty-two community-dwelling older adults aged 60 to 95 completed daily IADL tasks and daily measures of EF and busyness via ecological momentary assessment, independently at home for 18 days.

(1) In a subset of participants with mild EF weaknesses, high variability in busyness across days was associated with fewer tasks completed correctly; and (2) across all participants (regardless of EF), high levels of daily busyness were associated with fewer tasks completed on time.

Findings indicate that high variability in daily busyness, potentially reflecting a lack of daily routine, was associated with IADL errors among cognitively healthy older adults with mild EF weaknesses. Additionally, consistently high levels of busyness were associated with failures to complete tasks, or failures to complete them on time, regardless of EF. These results further support the Contextually Valid Executive Assessment (ConVExA) model, which posits that EF and contextual factors interact to predict functional outcomes.