Ecological, convergent, and discriminative validities of the cognitive abilities screening instrument in people with dementia

Spatial scale effects on associations between built environment and cognitive function: Multi-Ethnic Study of Atherosclerosis

Built environments have the potential to favorably support cognitive function. Despite growing work on this topic, most of the work has ignored variation in the spatial scale of the effect. The issue with spatial scale effects is that the size and shape of the areal unit within which built environment characteristics are measured naturally influence the built environment exposure metric and thus the estimated associations with health. We used spatial distributed lag modeling (DLM) to estimate how associations between built environment exposures (walkable destinations [WD], social destinations [SD]) and change in cognition varied across distance of these destinations from participants' residences. Cognition was assessed as maintained/improved processing speed (PS) and global cognition (GC). Person-level data from Exam 5 (2010-2012) and Exam 6 (2016-2018) of the Multi-Ethnic Study of Atherosclerosis was used (N = 1380, mean age 67). Built environment data were derived from the National Establishment Time Series. Higher availability of walkable and social destinations at closer distance from participants' residence was associated with maintained/improved PS. The adjusted associations between maintained/improved PS and destinations waned with increasing distance from the residence; associations were evident until approximately 1.9-km for WD and 1.5-km for SD. Associations were most apparent for participants living in areas with high population density. We found little evidence for associations between change in GC and built environment at any distance. These results highlight the importance of identifying appropriate spatial scale to understand the mechanisms for built environment-cognition associations.

Psychometric validation of the Cognitive Abilities Screening Instrument using Rasch analysis in people with dementia

This study aimed to examine unidimensionality of the Cognitive Abilities Screening Instrument (CASI) using Rasch analysis and estimate Rasch person reliability in people with dementia. CASI data of people with dementia was collected from medical records of one general hospital in northern Taiwan. A total of 506 people with dementia were recruited from the Department of Neurology. The confirmatory factor analysis was first conducted to verify the fitness of one-factor model of the CASI. Unidimensionality was confirmed through 2 assumptions: the infit and outfit mean square were 0.5 to 1.5, and residual variance of the first principal component in principal component analysis was ≤20%. Rasch person reliability was estimated after undimensionality was supported. The results of one-factor model had shown that the Comparative Fit Index = 0.99, Tucker Lewis Index = 0.99, Root Means Square Error of Approximation = 0.015, and Standardized Root Mean Square Residual = 0.067, representing a good fit to the model. Both the infit and outfit mean square were ranged 0.87 to 1.37 and 0.86 to 1.42, respectively, and low residual variance of the first principal component (12.3%). Rasch person reliability result of 0.58 was satisfactory. The person-item map indicated the difference between item difficulty and person ability was within the acceptable limits (0.22 logits). Differential Item Function was found between -0.48 to 0.44 logits for gender, indicating the CASI functioned similarly for both genders. The 46 items of the CASI showed a unidimensional construct. The CASI had been demonstrated as a valid and reliable screening tool for assessing overall cognitive function in people with dementia, capturing their cognitive functions effectively.

Longitudinal Associations between the Neighborhood Built Environment and Cognition in US Older Adults: The Multi-Ethnic Study of Atherosclerosis

Few studies have examined associations between neighborhood built environments (BE) and longitudinally measured cognition. We examined whether four BE characteristics were associated with six-year change in global cognition and processing speed. We obtained data on 1816 participants without dementia from the Multi-Ethnic Study of Atherosclerosis. BE measures included social destination density, walking destination density, proportion of land dedicated to retail, and network ratio (street connectivity). Global cognition was measured with the Cognitive Abilities Screening Instrument (CASI) and processing speed with the Digit Symbol Coding test (DSC). Multivariable random intercept logistic models tested associations between neighborhood BE at 2010-2012 and maintained/improved cognition (versus decline) from 2010-2018, and mediation by minutes of physical activity (PA)/week. The sample was an average of 67 years old (standard deviation = 8.2) (first cognitive measurement) and racially/ethnically diverse (29% African American, 11% Chinese, 17% Hispanic, 44% White). Compared to individuals with no walking destinations in the 1-mile surrounding their residence, those with 716 walking destinations (maximum observed) were 1.24 times more likely to have maintain/improved DSC score (Odds ratio: 1.24; 95% confidence interval: 1.03-1.45). No other associations were observed between BE and cognition, and PA minutes/week did not mediate the association between walking destination density and DSC change. This study provides limited evidence for an association between greater neighborhood walking destinations and maintained/improved processing speed in older age and no evidence for associations between the other BE characteristics and cognition. Future studies with finer grained BE and cognitive measures and longer-term follow up may be required.