Functional abilities in older adults with mild cognitive impairment.

Background: A classification scheme and general set of criteria for diagnosing mild cognitive impairment (MCI) were recently proposed by a multidisciplinary group of experts who met at an international symposium on MCI. One of the proposed criteria included preserved basic activities of daily living and minimal impairment in complex instrumental activities of daily living (IADLs).

Objective: To investigate whether older adults with MCI classified according to the subtypes identified by the Working Group (i.e. amnestic, single non-memory domain, and multiple domain with or without a memory component) differed from cognitively intact older adults on a variety of measures indexing IADLs and to examine how well measures of IADL predict concurrent MCI status.

Methods: Two hundred and fifty community-dwelling older adults, ranging in age from 66 to 92, completed self-report measures of IADLs (Lawton and Brody IADL Scale, Scales of Independent Behaviour-Revised--SIB-R) and a measure of everyday problem solving indexing IADLs (Everyday Problems Test--EPT). Ratings of participants' IADL functioning were also obtained from informants (e.g. spouse, adult child and friend).

Results: Older adults with multiple-domain MCI demonstrated poorer IADL functioning than older adults with no cognitive impairment on the EPT and the SIB-R (both self- and informant-report versions). The multiple-domain MCI participants also demonstrated poorer IADLs than MCI participants with impairments in a single cognitive domain on the self-reported SIB-R and EPT. The single-domain MCI groups demonstrated poorer IADLs than older adults without cognitive impairment on the informant-reported SIB-R and EPT. No significant group differences were found on the Lawton and Brody IADL Scale. Using the EPT and SIB-R as predictors in a multinomial regression analysis, MCI group status was reliably predicted, but the classification rate was poor.

Conclusion: Individuals with MCI demonstrated poorer IADL functioning compared to cognitively intact older adults. However, the changes in IADL functioning observed in MCI may be too subtle to be detected by certain measures, such as the Lawton and Brody IADL Scale.