Brief informant screening test for mild cognitive impairment and early Alzheimer's disease

Recent research has attempted combinations of instruments to improve screening accuracy for mild cognitive impairment (MCI) and early Alzheimer's disease (AD). We compared Mini-Mental State Examination (MMSE), Immediate and Delayed Recall (Logical Memory I and II; LM-I and LM-II, respectively), a single-item informant report of memory problem (IRMP), and a four-item Instrumental Activities of Daily Living (4IADL) scale, and combinations of these tests.

The tests were administered together with Clinical Dementia Rating (CDR) to subjects who were cognitively intact (CDR = 0, n = 88), and with diagnoses of MCI (CDR = 0.5, n = 37) and early AD (CDR = 1-2, n = 19).

Screening accuracy (receiver operating characteristic area under curve, AUC) for identifying MCI or MCI-AD was lowest for MMSE (AUC 67.6% for MCI or 77.9% for MCI-AD), and better for IRMP (79.5 or 83.2%), 4IADL (76.9 or 84.7%), LM-I (81.2 or 87.1%) and LM-II (86.1 or 90.8%). Combining IRMP, 4IADL and LM-II was most accurate (AUC 91.7% for MCI or 94.5% for MCI-AD); sensitivity: 86.5 or 89.3%; specificity: 86.4 or 88.6%. However, combining IRMP and 4IADL gave nearly as good accuracy (AUC 87.2 or 91.6%); sensitivity: 86.5 or 85.7%; specificity: 79.5 or 85.2%.

A brief instrument combining an IRMP and 4IADL items is potentially useful in screening for MCI and early AD.