Predictors of Improvement after Cognitive Training in Mild Cognitive Impairment: Insights from the Cognitive Training and Neuroplasticity in Mild Cognitive Impairment Trial.

OBJECTIVE: Cognitive training may benefit older adults with mild cognitive impairment (MCI), but the prognostic factors are not well-established. METHODS: This study analyzed data from a 78-week trial with 107 participants with MCI, comparing computerized cognitive training (CCT) and computerized crossword puzzle training (CPT). Outcomes were changes in cognitive and functional measures from baseline. Linear mixed-effect models were used to identify prognostic factors for each intervention. RESULTS: Baseline neuropsychological composite z-score was positively associated with cognitive and functional improvements for both interventions in univariable models, retaining significance in the final multivariable model for functional outcome in CPT ( P < 0.001). Apolipoprotein E e4 carriers had worse cognitive ( P = 0.023) and functional ( P = 0.001) outcomes than noncarriers for CPT but not CCT. African Americans showed greater functional improvements than non-African Americans in both CPT ( P = 0.001) and CCT ( P = 0.010). Better baseline odor identification was correlated with cognitive improvements in CPT ( P = 0.006) and functional improvements in CCT ( P < 0.001). CONCLUSION: Baseline cognitive test performance, African American background, and odor identification ability are potential prognostic factors for improved outcomes with cognitive interventions in older adults with MCI. Apolipoprotein E e4 is associated with poor outcomes. Replication of these findings may improve the selection of cognitive interventions for individuals with MCI.

Characterizing Neighborhood Vulnerabilities in Mild Cognitive Impairment using the Environmental Justice Index.

Background: There is a need for integration and comprehensive characterization of environmental determinants of Alzheimer's disease. The Environmental Justice Index (EJI) is a new measure that consolidates multiple environmental health hazards. Objective: This analysis aims to explore how environmental vulnerabilities vary by race/ethnicity and whether they predict cognitive outcomes in a clinical trial of mild cognitive impairment (MCI). Methods: We used data from a clinical trial of 107 MCI participants (28% minorities). Using the EJI, we extracted 40 measures of neighborhood environmental and social vulnerability including air and water pollution, access to recreational spaces, exposure to coal and lead mines, and area poverty. We also examined the relationship of the EJI to the Area Deprivation Index (ADI). Data was analyzed using regressions, correlations, and t-tests. Results: Environmental Burden Rank (EBR) across the sample (0.53±0.32) was near the 50th percentile nationally. When divided by race/ethnicity, environmental (p = 0.025) and social (p < 0.0001) vulnerabilities were significantly elevated for minorities, specifically for exposure to ozone, diesel particulate matter, carcinogenic air toxins, and proximity to treatment storage and disposal sites. ADI state decile was not correlated with the EBR. Neither EBR nor ADI were a significant predictor of cognitive decline. Conclusions: To our knowledge, this is the first study to link the EJI to an MCI trial. Despite limitations of a relatively small sample size, the study illustrates the potential of the EJI to provide deeper phenotyping of the exposome and diversity in clinical trial subjects.