Three-Year Changes in Cognitive and Brain Functions Among Community-Dwelling Older Adults Who Continue Working

Prevention of cognitive decline in older adults is a critical public health issue in rapidly ageing societies. Studies indicate that engagement in instrumental activities of daily living (IADL) and social participation is associated with better cognitive function. Employment incorporates elements of IADL and social participation; however, longitudinal evidence describing cognitive and brain function changes in older adults who continue working is scarce. Hence, this study aimed to longitudinally examine changes in cognitive and brain functions over a three-year period among older adults who continued working.

The participants were 23 community-dwelling older adults aged 65 years and older who completed baseline and follow-up assessments. Cognitive function was assessed using the Japanese version of the Montreal Cognitive Assessment (MoCA-J), Trail Making Test Parts A and B (TMT-A and TMT-B) and behavioural performance on a Go/No-go task. Brain function was evaluated using event-related potentials (ERPs), focusing on the No-go P3 component as an index of inhibitory control. The baseline and follow-up data were compared using paired statistical analyses.

The MoCA-J scores significantly improved at follow-up compared with those of baseline (p < 0.001). In the Go/No-go task, No-go accuracy significantly increased (p = 0.017). ERP analyses revealed that the No-go P3 amplitude significantly increased at follow-up at the Fz (p < 0.001), Cz (p = 0.002) and Pz (p = 0.004) electrodes, whereas the No-go P3 latency showed no significant change.

Older adults who continued working displayed improvements in global cognitive function, behavioural measures of inhibitory control and associated neural activity over a three-year period. Although causal relationships cannot be established in the absence of a non-working comparison group, our study provides longitudinal descriptive evidence of cognitive and neural changes in older adults who remain employed.