Negative Emotional Verbal Memory Biases in Mild Cognitive Impairment and Late-Onset Depression

Early and preferential targeting of limbic structures by Alzheimer disease (AD)-related pathology suggests emotion dysregulation may serve as a marker of AD risk. We studied emotional verbal memory in two groups at risk for AD, amnestic mild cognitive impairment (aMCI) and late-onset depression (LOD), to test the hypothesis that aMCI and LOD would be characterized by a negative bias in emotional memory, whereas cognitively normal (CN) adults would show the "positivity effect" associated with healthy aging.

Participants completed a novel test of emotional verbal memory, the Emotional Verbal Learning Test (EVeLT), consisting of a 15-item list of words with positive, negative, or neutral valence. Recall as a function of group and valence was analyzed using mixed analysis of variance. Spearman's rho was used to examine associations between EVeLT, mood, and executive function. MCI and CN participants had no current or past history of mood or anxiety disorders. aMCI participants met neuropsychological criteria for single-domain aMCI (sd-aMCI). LOD developed their first episode of depression at ≥60 years of age.

CN adults recalled more positive words, whereas sd-aMCI and LOD adults recalled more negative, relative to neutral, words on the EVeLT. Positive emotional memory and negative attitudes regarding self were inversely correlated in CN adults.

sd-aMCI and LOD groups show negative emotional memory biases, consistent with our hypothesis that emotion dysregulation is a signature of AD risk.