Memory Binding Test Distinguishes Amnestic Mild Cognitive Impairment and Dementia from Cognitively Normal Elderly

Abstract

Objective: We aimed to assess reliability and cross-sectional discriminative validity of the Memory Binding Test (MBT) to distinguish persons with amnestic cognitive impairment (aMCI) and dementia from cognitively normal elderly controls.

Method: The MBT was administered to 20 participants with dementia, 31 with aMCI and 246 controls, who received the first administration of the MBT from May 2003 to December 2007, as a substudy of the community-based Einstein Aging Study (age range: 70+). The optimal index resulted from comparing the partial area under the receiver operating characteristic curves (ROC AUC) of four major MBT indices for specificities ≥0.70. Optimal cut-score of the optimal index was selected by maximizing the sum of sensitivity and specificity. Age and education effects were assessed using stratified cut-scores and adjusted logistic regression. Reliability was computed as intraclass correlation between scores at baseline and 1-year follow-up for participants who remained cognitively normal.

Results: Total number of Items recalled in the Paired condition (TIP) was elected the optimal index. TIP cut-score was ≤22 for differentiating aMCI alone (sensitivity = 0.74, specificity = 0.73) and aMCI and dementia combined (sensitivity = 0.84, specificity = 0.73) from controls. It was ≤17 for differentiating dementia from aMCI and controls (sensitivity = 0.95, specificity = 0.87). Age and education adjustments did not materially improve discriminative validity. The reliability of TIP was 0.77.

Conclusions: MBT achieved moderate to good reliability. TIP had superior cross-sectional discriminative validity than the other MBT indices. We recommend using the empirical cut-score of TIP ≤22 for discriminating aMCI and dementia and ≤17 for discriminating dementia alone.

Keywords: Alzheimer's disease; Dementia; Elderly/geriatrics/aging; Learning and memory; Mild cognitive impairment.