Can performance on daily activities discriminate between older adults with normal cognitive function and those with mild cognitive impairment?

Abstract

Objectives: To examine whether preclinical disability in performance of cognitively focused instrumental activity of daily living (C-IADL) tasks can discriminate between older adults with normal cognitive function and those with mild cognitive impairment (MCI) and, secondarily, to determine the two tasks with the strongest psychometric properties and assess their discriminative ability so as to generate diagnosis-relevant information about cognitive changes associated with MCI and mild neurocognitive disorder according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, criteria.

Design: Secondary analyses of cross-sectional data from a cohort of individuals diagnosed with normal cognitive function or MCI.

Setting: Pittsburgh, Pennsylvania.

Participants: Older adults with remitted major depression (N = 157).

Measurements: Diagnosis of cognitive status was made at the Alzheimer's Disease Research Center, University of Pittsburgh. Performance on eight C-IADLs was measured using the criterion-referenced, observation-based Performance Assessment of Self-Care Skills (PASS).

Results: Ninety-six older adults with normal cognitive function (mean age 72.5 ± 5.9) and 61 with MCI (mean age 75.5 ± 6.3) participated. The eight C-IADLs demonstrated 81% accuracy in discriminating cognitive status (area under the receiver operating characteristic curve (AUC) = 0.81, P < .001). Two tasks (shopping and checkbook balancing) were the most discriminating (AUC = 0.80, P < .001); they demonstrated similar ability as all eight C-IADLs in determining cognitive status. Assessing performance on these two C-IADLs takes 10 to 15 minutes.

Conclusion: This is the first demonstration of the discriminative ability of preclinical disability to distinguish older adults with MCI from cognitively normal older adults. These findings highlight potential tasks that, when measured using the observation-based PASS, demonstrate greater effort for individuals with MCI. These tasks may be considered when attempting to diagnose MCI or mild neurocognitive disorder in clinical practice and research.

Keywords: activities of daily living; cognitive function; instrumental activities of daily living; mild cognitive impairment; mild neurocognitive disorder.

Figure 1

Individual and combined C-IADL Receiver Operating Characteristic curves Note: Receiver operating characteristic curves for each for the 8 C-IADL. The areas under the curves were 0.74 for shopping, 0.65 for bill paying, 0.72 for checkbook balancing, 0.59 for bill mailing, 0.60 for telephone use, 0.67 for medication management, 0.61 for critical information retrieval, and 0.60 for small item repair. Receiver operating characteristic curves for the total scores for the 8 C-IADL and the 2 C-IADL. The areas under the curves were 0.81 for the 8 tasks and 0.80 for the 2 tasks.