Cognitive activities during adulthood are more important than education in building reserve.

Cognitive reserve is thought to reflect life experiences. Which experiences contribute to reserve and their relative importance is not understood. Subjects were 652 autopsied cases from the Rush Memory and Aging Project and the Religious Orders Study. Reserve was defined as the residual variance of the regressions of cognitive factors on brain pathology and was captured in a latent variable that was regressed on potential determinants of reserve. Neuropathology variables included Alzheimer's disease markers, Lewy bodies, infarcts, microinfarcts, and brain weight. Cognition was measured with six cognitive domain scores. Determinants of reserve were socioeconomic status (SES), education, leisure cognitive activities at age 40 (CA40) and at study enrollment (CAbaseline) in late life. The four exogenous predictors of reserve were weakly to moderately inter-correlated. In a multivariate model, all except SES had statistically significant effects on Reserve, the strongest of which were CA40 (ß = .31) and CAbaseline (ß = .28). The Education effect was negative in the full model (ß = -.25). Results suggest that leisure cognitive activities throughout adulthood are more important than education in determining reserve. Discrepancies between cognitive activity and education may be informative in estimating late life reserve.

Composite scores for executive function items: demographic heterogeneity and relationships with quantitative magnetic resonance imaging.

Accurate neuropsychological assessment of older individuals from heterogeneous backgrounds is a major challenge. Education, ethnicity, language, and age are associated with scale level differences in test scores, but item level bias might contribute to these differences. We evaluated several strategies for dealing with item and scale level demographic influences on a measure of executive abilities defined by working memory and fluency tasks. We determined the impact of differential item functioning (DIF). We compared composite scoring strategies on the basis of their relationships with volumetric magnetic resonance imaging (MRI) measures of brain structure. Participants were 791 Hispanic, white, and African American older adults. DIF had a salient impact on test scores for 9% of the sample. MRI data were available on a subset of 153 participants. Validity in comparison with structural MRI was higher after scale level adjustment for education, ethnicity/language, and gender, but item level adjustment did not have a major impact on validity. Age adjustment at the scale level had a negative impact on relationships with MRI, most likely because age adjustment removes variance related to age-associated diseases.

Spanish and English neuropsychological assessment scales: relationship to demographics, language, cognition, and independent function.

This study examined the relationship of the Spanish and English Neuropsychological Assessment Scales (SENAS) to demographic, cultural, and language fluency variables and to measures of cognition and independent functioning. Participants were 367 Hispanics and 160 Caucasians in the 60+ years age range, all living in the community. In Study 1, education and language use had strong influences on SENAS scores and largely explained ethnic group differences in mean scale scores. Age had weak effects on most scales except for verbal memory measures. Acculturation effects in Hispanics were largely accounted for by education and language use. Study 2 showed equivalent sensitivity of SENAS to cognitive and functional status in Hispanics and Caucasians. Results indicate that interpretation of SENAS scores must be informed by effects related to education and language fluency but provide evidence of equivalent validity in Hispanics and Caucasians with respect to concurrent measures of cognition and independent function.

Spanish and English Neuropsychological Assessment Scales (SENAS): further development and psychometric characteristics.

The Spanish and English Neuropsychological Assessment Scales were devised to be a broad set of psychometrically matched measures with equivalent Spanish and English versions. Study 1 in this report used item response theory methods to refine scales. Results strongly supported psychometric matching across English and Spanish versions and, for most scales, within English and Spanish versions. Study 2 supported in both English and Spanish subsamples the 6-domain model of ability that guided scale construction. Study 3 examined differential item functioning (DIF) of one scale (Object Naming) in relation to education, ethnicity, gender, and age. Effects of DIF on scale-level ability scores were limited. Results demonstrate an empirically guided psychometric approach to test construction for multiethnic and multilingual test applications.

Psychometrically matched measures of global cognition, memory, and executive function for assessment of cognitive decline in older persons.

Item response theory methods were used to derive psychometrically sophisticated measures of global cognition, memory, and executive function. Goals were that these measures (a) could be derived from commonly used neuropsychological tests, (b) would have linear measurement properties, and (c) would be psychometrically matched. Scale development was based on a sample of 400 older individuals with cognitive function ranging from normal to demented. Scales were reasonably matched with linear measurement over an ability range relevant to many important clinical applications. Cognitively normal, mild impairment, and dementia participant groups differed on baseline measures and rate of decline. Association of measures with quantitative structural magnetic resonance imaging variables followed expected patterns. This approach to scale development may have applications for other neuropsychological assessment problems.