Predictors of rate of cognitive decline in patients with amnestic mild cognitive impairment

Amnestic mild cognitive impairment (MCI) is a known risk factor for conversion to Alzheimer's disease (AD). Although substantial research has been conducted on the general profile of amnestic MCI subjects and predictors of conversion to AD, research on predictors of rate of decline has been considerably less extensive. The present study sought to more systematically and comprehensively examine predictors of rate of cognitive decline in a longitudinal sample of individuals with MCI, including age, genetic vulnerability, baseline cognitive performance, and baseline neuropsychiatric severity.

Participants with single or multi-domain amnestic MCI (N = 151) were assessed at baseline and for a mean of 1.32 follow-up visits (mean interval from baseline to last follow-up = 1.61 years).

Results showed that carriers of the ApoE ε4 allele declined more quickly on all three dementia severity measures compared to non-carriers. Older individuals did not decline more rapidly in dementia severity. Participants with lower executive functions composite scores and greater memory impairment severity at baseline predicted faster decline on dementia severity measures. Contrary to hypotheses, those with lower levels of depression at baseline declined more rapidly on dementia severity measures compared to those with higher levels of depression.

Identifying potential predictors of rate of decline from amnestic MCI to AD could be clinically meaningful for prognostic purposes, understanding risk and protective factors, as well as guiding future treatments and clinical trials that could aim to target and delay progression among those patients who are vulnerable to more quickly convert to AD.