Stress and its impact on cognition in mild cognitive impairment

Abstract

Participants with amnestic Mild Cognitive Impairment (aMCI) do not inevitably show cognitive decline or convert to Alzheimer’s disease (AD) supporting the hypothesis that secondary events are crucial in the conversion process. Research suggests that psychological stress is a risk factor for AD. Therefore, we proposed psychological stress will be associated with worsened cognitive decline, a clinical marker of advancing neurodegeneration.

This was a longitudinal observational study assessing the association between the degree of psychological stress and cognitive decline in 134 aMCI participants and 69 control participants. We hypothesised that stress, as measured by the Recent Life Change Questionnaire (RLCQ), would be associated with worsened cognitive decline, as measured by the Free and Cued Selective Reminding Test with Immediate Recall (FCSRT-IR), over an 18 month follow-up period. Other secondary cognitive outcomes included the difference in change of the Montreal Cognitive Assessment score and the Trail Making Test Part B. Exploratory measures of stress included the Perceived Stress Scale and the presence of physical stressors. Hypothesised modulators of the stress response were assessed including mood, neuroticism, social support, and favoured coping style. Biological outcomes included changes in blood levels of inflammatory markers and salivary cortisol.

Objective stressful life events occurring during the course of the study were associated with increased rates of cognitive decline across a range of measures in the aMCI group. Whereas, as predicted, psychological stress was not associated with cognitive decline in the control group. Presence of the ApoE ε4 allele was associated with an increased rate of cognitive decline and increased serum levels of the anti-inflammatory cytokine TGFβ was associated with a slower rate of cognitive decline in the aMCI group. We found that neither measures of mood nor potential modulators of stress exerted a consistent significant influence over rates of cognitive decline in the aMCI group.

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Identifiers

ORCID for Clive Holmes: orcid.org/0000-0003-1999-6912

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