Performance-Based vs Informant-Reported Instrumental Activities of Daily Living in Predicting Dementia.

Abstract

Identifying individuals at risk of developing dementia may be aided by early detection of functional impairments. The aims of the present study were to examine differences in informant-reported and performance-based measures of instrumental activities of daily living (IADL) and to assess whether a performance-based IADL measure contributes additional unique variance over informant reports in predicting incident dementia over 4years. Prospective cohort study (Sydney Memory and Ageing Study). Eastern Suburbs, Sydney, Australia. 307 community-dwelling individuals (60.6% female) aged between 76 and 96years with normal cognition (NC; n= 190) or mild cognitive impairment (MCI; n= 117). IADL ability was assessed with the performance-based Sydney Test of Activities of Daily Living in Memory Disorders (STAM) and the Bayer-Activities of Daily Living (B-ADL) informant report, at baseline and 4-year follow-up. Covariates included age, sex, education, Mini-Mental State Examination and Geriatric Depression Scale scores, arthritis, vision impairment, cardiovascular risk, and number of medications. Logistic regressions were conducted to examine the longitudinal association between the 2 types of IADL measures and incident dementia. Logistic regressions showed that performance-based IADL impairment at baseline [odds ratio (OR)= 0.83, 95% confidence interval (CI) 0.77, 0.90; P < .001] and decline in performance-based IADL function (OR= 0.82, 95% CI 0.73, 0.91; P < .001) were associated with incident dementia over 4years, with the association provided by the STAM being statistically significant over and above the B-ADL. Performance-based measures of IADL can predict progression to dementia over 4years beyond that provided by an informant report of IADL. Performance-based IADL measures are promising tools for clinical practice to identify individuals at greater risk of developing dementia.