Purpose in Life and Functional Reserve in a Memory Clinic Sample

Preserving functional independence as cognitive abilities decline is crucial for maintaining quality of life and easing caregiving burden. We examined whether Purpose in Life (PIL), a psychological resource tied to healthier aging trajectories, was associated with functional reserve - the capacity to maintain IADLs better than expected, given one's cognitive status. Furthermore, we examined whether the association between PIL and functional reserve would be explained by personality differences.

Patients completed measures of cognition and PIL, the Lawton Brody IADL scale, and the NEO Five Factor Inventory, and caregivers also rated patients on IADLs. Following its definition, functional reserve was estimated as the residuals from the regression of IADL scores on cognitive domain scores and demographics. Linear regression models then examined the association of PIL with functional reserve alone, and then adjusting for FFM domains.

Higher PIL was strongly associated with better functional reserve measured from both patient reports of IADLs (p <0.001) as well as caregiver ratings of IADLs (p <0.001). FFM personality dimensions attenuated the PIL-functional reserve association roughly 23% for functional reserve scores from patient IADL ratings but only led to minimal attenuation of PIL-functional reserve associations when the latter was measured from caregiver-rated IADLs.

The enhanced goal-directedness and motivation characteristic of more purposeful living may allow people to maintain better IADL function than expected given their cognitive status. More work is needed to probe the longitudinal nature of this association, and to test whether interventions enhancing PIL also promote functional reserve.