Longitudinal declines in instrumental activities of daily living in stable and progressive mild cognitive impairment.

BACKGROUND: Previous cross-sectional studies suggest that assessments of instrumental activities of daily living (IADLs) may be useful for operationalizing the differences in functional deficits seen in mild cognitive impairment (MCI) and dementia. However, their utility for longitudinal changes in IADLs in the transition between MCI and dementia remains unclear.

METHODS: We analyzed longitudinal IADL data with the Functional Activities Questionnaire (FAQ) in stable (MCI-S; n = 1,318) or progressive (MCI-P; n = 1,108) MCI patients.

RESULTS: Larger increases in FAQ scores were seen in the MCI-P group across a 14.5-month interval, but overlapping distributions in the two groups yielded poorer discriminatory power than prior cross-sectional reports.

CONCLUSION: Our findings emphasize the difficulties in operationalizing the criterion of 'essentially intact' IADLs in MCI, which may complicate the interpretation of disease progression in MCI treatment trials.