The Use of Episodic Memory Tests for Screening in Clinical Trials for Early Alzheimer's Disease: A Comparison of the Free and Cued Selective Reminding Test (FCSRT) and the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS).

BACKGROUND: Screening procedures for early Alzheimer's disease (AD) trials seek to efficiently identify participants who fulfill clinical and biomarker criteria for AD and enrich for those most likely to experience significant clinical progression during the study. Episodic memory performance is often assessed in screening, but the utility of different memory tests for optimizing screening efficiency and/or rates of clinical progression remains uncertain. OBJECTIVES: Cross-study comparisons of the effects of inclusion criteria based on performance on the Free and Cued Selective Reminding Test (FCSRT) or the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) on screen-failure rates for episodic memory and ß-amyloid (Aß) positivity (by CSF or PET) and on subsequent rates of clinical disease progression in randomized participants across three clinical trials in early (prodromal-to-mild) AD. DESIGN: Secondary analyses of cross-sectional and longitudinal clinical trial data. SETTING: Multi-center international clinical trials. PARTICIPANTS: Individuals with prodromal-to-mild AD screened and/or randomized in clinical trials for crenezumab (CREAD, CREAD2) or semorinemab (Tauriel). Cross-sectional analyses of screening data for episodic memory impairment included participants from CREAD2 (n=2897) and Tauriel (n=887) and for Aß positivity included participants from CREAD (n=1138), CREAD2 (n=1119), and Tauriel (n=483). Longitudinal analyses of rates of clinical progression included participants from CREAD (n=779), CREAD2 (n=773), and Tauriel (n=331). MEASUREMENTS: Cross-sectional analyses examined eligibility rates per cutoffs defined for the FCSRT (CREAD, CREAD2) or RBANS (Tauriel) and per Aß positivity using CSF and/or PET biomarkers. Longitudinal analyses examined rates of clinical progression on the Clinical Dementia Rating-Sum of Boxes (CDR-SB), the 13-item version of the Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog13), and Alzheimer's Disease Cooperative Study-Activities of Daily Living Scale (ADCS-ADL). RESULTS: Lower rates of study eligibility per episodic memory criteria were seen with the FCSRT (CREAD2) relative to the RBANS (Tauriel), but similar rates of eligibility per Aß positivity criteria were seen amongst participants with episodic memory impairment per the cutoffs used on either assessment. Similar rates of clinical decline over 18 months on the CDR-SB, ADAS-Cog13, and ADCS-ADL were observed in study populations enriched using the FCSRT (CREAD, CREAD2) or the RBANS (Tauriel). CONCLUSIONS: Cutoffs for episodic memory impairment on the FCSRT used in the CREAD and CREAD2 studies are more stringent than those on the RBANS used in the Tauriel study, resulting in lower rates of eligibility. However, given that study enrichment with either test yields similar rates of Aß positivity and clinical progression, considerations beyond these factors may drive the decision of which assessment to use for screening in early AD clinical trials.

Cognitive Performance Does not Limit Physical Activity Participation in the Lifestyle Interventions and Independence for Elders Pilot Study (LIFE-P).

OBJECTIVES: We examined whether multiple domains of baseline cognitive performance were associated with prospective physical activity (PA) adherence in the Lifestyle Interventions and Independence for Elders Pilot study (LIFE-P). DESIGN, SETTING, PARTICIPANTS: The LIFE-P study was a single-blind, multicenter, randomized controlled trial of a PA intervention compared to a successful aging educational intervention in sedentary, mobility-limited older adults. INTERVENTION: A 12-month structured, moderate-intensity, multi-modal PA program that included walking, resistance training, and flexibility exercises. For the first 2 months (adoption), 3 center-based exercise sessions (40-60 min) / week were conducted. During the next 4 months (transition), center-based sessions were conducted 2 times / week. The subsequent maintenance phase consisted of optional once-to-twice-per-week center-based sessions and home-based PA. MEASUREMENTS: Tests of executive and global cognitive functioning, working memory and psychomotor speed were administered at baseline. Median test scores were used to dichotomize participants into low or high cognitive performance groups. RESULTS: 52 mobility-limited older adults (age: 76.9 ±5 yrs) were randomized to the PA arm of LIFE-P. Compared to participants with high cognitive performance, participants with low performance had similar PA adherence rates (all P ≥ 0.34). Furthermore, weak and non-significant univariate relationships were elicited between all measures of cognition and overall PA adherence levels (r values ranged: -0.20 to 0.12, P ≥ 0.12). CONCLUSION: These data suggest that cognitive performance does not limit long-term PA adherence in mobility-limited older adults. Additional studies in larger cohorts are warranted to verify these findings.

Effects of Type 2 Diabetes on Brain Structure and Cognitive Function: African American-Diabetes Heart Study MIND.

BACKGROUND AND PURPOSE: Rates of type 2 diabetes are higher among African Americans compared with individuals of European ancestry. The purpose of this investigation was to determine the relationship between MR imaging measures of brain structure (volume of GM, WM, WM lesions) and cognitive function in a population of African Americans with type 2 diabetes. These MR imaging measures of brain structure are affected by type 2 diabetes-associated macrovascular and microvascular disease and may be associated with performance on tasks of cognitive function in the understudied African American population. MATERIALS AND METHODS: African Americans with type 2 diabetes enrolled in the African American-Diabetes Heart Study MIND study (n = 263) were evaluated across a broad range of cognitive domains and imaged with brain MR imaging. Associations between cognitive parameters and MR imaging measures of whole-brain GM, WM, and WM lesion volumes were assessed by using adjusted multivariate models. RESULTS: Lower GM volume was associated with poorer performance on measures of general cognitive function, working memory, and executive function. Higher WM lesion volume was associated with poorer performance on a smaller subset of cognitive domains compared with GM volume but included aspects of working memory and executive function. There were no statistically significant associations with WM volume. CONCLUSIONS: Markers of cortical atrophy and WM lesion volume are associated with cognitive function in African Americans with type 2 diabetes. These associations are described in an African American cohort with disease control similar to that of individuals of European ancestry, rather than underserved African Americans with poor access to health care. Interventions to reduce cortical atrophy and WM disease may improve cognitive outcomes in this understudied population.