Measures That Predict Progression From Mild Cognitive Impairment to Alzheimer’s Type Dementia: A Retrospective Study

Abstract

By 2060 an estimated 15 million individuals in the United States are predicted to be diagnosed with Alzheimer’s Disease (AD) or a prodromal stage of AD called mild cognitive impairment (MCI) (Brookmeyer & Abdalla, 2018). MCI is referred to as the intermediate state of cognitive function between the changes seen in normal aging and meeting diagnostic criteria for dementia (Petersen, 2011). However, research has found that a diagnosis of MCI does not guarantee a progression to dementia and that some may continue to stay stable (MCI stable) or revert back to normal cognition (MCI reversion). Predictors for individuals at risk for MCI or individuals with MCI who convert to dementia has been well-documented while predictors for MCI reversion and MCI stable are limited. Pandya et al. (2015) found predictors most significantly associated with MCI reversion were younger age, female gender, being unmarried, more functional independence at baseline, and tests of delayed memory, language, and processing speed. There were no associations found between level of education and immediate verbal memory. This study sought to build upon Pandya et al. by examining whether group membership (MCI converter and Dementia reverter) can be predicted by demographic, functional ability, neuropsychological functioning, and neuropsychiatric symptoms when participants are followed for more than three years. This retrospective study incorporated data from the National Alzheimer’s Coordinating Center (NACC) Uniform Data Set (UDS). The study used a binary logistic regression predicting dementia diagnosis using forward stepwise procedure. Results indicated that demographic variables (X²=3.762, df=1, p=0.439; Nagelkerke R²=0.021), functional ability (X²=1.518, df=1, p=0.218; Nagelkerke R²=0.010), neuropsychological functioning (X²=1.693, df=1, p=0.638; Nagelkerke R²=0.010), and neuropsychiatric symptoms (X²=3.323, df=1, p=0.068; Nagelkerke R²=0.018) did not predict group membership. Results of the current study were not consistent with prior research. Most individuals with MCI ultimately converted onto dementia when followed for more than three years and risk factors that were previously found to predict MCI reversion did not significantly predict reversion for individuals in this study sample. Findings may help with future care and treatment and allow individuals and families to ultimately make important decisions for their care. Future studies should examine MCI reversion and stability through a longitudinal study that includes access to data from larger sample population.