Longitudinal Trajectories of Participant- and Study Partner-Rated Cognitive Decline, in Relation to Alzheimer's Disease Biomarkers and Mood Symptoms

Genetic Risk for Alzheimer's Disease Alters Perceived Executive Dysfunction in Cognitively Healthy Middle-Aged and Older Adults

Background

Subjective cognitive complaints (SCC) may be an early indicator of future cognitive decline. However, findings comparing SCC and objective cognitive performance have varied, particularly in the memory domain. Even less well established is the relationship between subjective and objective complaints in non-amnestic domains, such as in executive functioning, despite evidence indicating very early changes in these domains. Moreover, particularly early changes in both amnestic and non-amnestic domains are apparent in those carrying the Apolipoprotein-E ɛ4 allele, a primary genetic risk for Alzheimer's disease (AD).

Objective

This study investigated the role of the ɛ4 allele in the consistency between subjective and objective executive functioning in 54 healthy, cognitively intact, middle-aged and older adults.

Methods

Participants (Mage = 64.07, SD = 9.27, range = 48-84; ɛ4+ = 18) completed the Frontal Systems Behavior Scale (FrSBe) Executive Dysfunction Scale (EXECDYS) to measure subjective executive functioning (SEF) and multiple executive functioning tasks, which were condensed into a single factor.

Results

After accounting for age, depression, and anxiety, objective executive functioning performance significantly predicted SEF. Importantly, ɛ4 moderated this effect. Specifically, those carrying the ɛ4 allele had significantly less accurate self-awareness of their executive functioning compared to ɛ4 non-carriers.

Conclusions

Utilizing an approach that integrates self-evaluation of executive functioning with objective neurocognitive assessment may help identify the earliest signs of impending cognitive decline, particularly in those with genetic risk for AD. Such an approach could sensitively determine those most prone to future cognitive decline prior to symptom onset, when interventions could be most effective.

Predicting progression of cognitive decline to dementia using dyadic patterns of subjective reporting: evidence from the CompAS longitudinal study

Objective

To analyze the validity of self and informant reports, depressive symptomatology, and some sociodemographic variables to predict the risk of cognitive decline at different follow-up times.

Methods

A total of 337 participants over 50 years of age included in the CompAS and classified as Cognitively Unimpaired (CU), Subjective Cognitive Decline (SCD) and Mild Cognitive Impairment (MCI) groups were assessed at baseline and three follow-ups. A short version of the QAM was administered to assess the severity of subjective cognitive complaints (SCCs), and the GDS-15 was used to evaluate the depressive symptoms. At each follow-up assessment, participants were reclassified according to the stability, regression or progression of their conditions. Logistic regression analysis was used to predict which CU, SCD and MCI participants would remain stable, regress or progress at a 3rd follow-up by using self- and informant-reported complaints, depressive symptomatology, age and education at baseline and 2nd follow-ups as the predictive variables.

Results

Overall, self-reported complaints predicted progression between the asymptomatic and presymptomatic stages. As the objective deterioration increased, i.e., when SCD progressed to MCI or dementia, the SCCs reported by informants proved the best predictors of progression. Depressive symptomatology was also a predictor of progression from CU to SCD and from SCD to MCI.

Conclusion

A late increase in self-reported complaints make valid estimates to predict subjective decline at asymptomatic stages. However, an early increase in complaints reported by informants was more accurate in predicting objective decline from asymptomatic stages. Both, early and late decrease in self-reported complaints successfully predict dementia from prodromic stage. Only late decrease in self-reported complaints predict reversion from prodromic and pre-symptomatic stages.

Brain Health Registry Study Partner Portal: Novel infrastructure for digital, dyadic data collection

BACKGROUND

In Alzheimer's disease (AD) research, subjective reports of cognitive and functional decline from participant-study partner dyads is an efficient method of assessing cognitive impairment and clinical progression.

METHODS

Demographics and subjective cognitive/functional decline (Everyday Cognition Scale [ECog]) scores from dyads enrolled in the Brain Health Registry (BHR) Study Partner Portal were analyzed. Associations between dyad characteristics and both ECog scores and study engagement were investigated.

RESULTS

A total of 10,494 BHR participants (mean age = 66.9 ± 12.16 standard deviations, 67.4% female) have enrolled study partners (mean age = 64.3 ± 14.3 standard deviations, 49.3% female), including 8987 dyads with a participant 55 years of age or older. Older and more educated study partners were more likely to complete tasks and return for follow-up. Twenty-five percent to 27% of older adult participants had self and study partner-report ECog scores indicating a possible cognitive impairment.

DISCUSSION

The BHR Study Partner Portal is a unique digital tool for capturing dyadic data, with high impact applications in the clinical neuroscience and AD fields. Highlights The Brain Health Registry (BHR) Study Partner Portal is a novel, digital platform of >10,000 dyads. Collection of dyadic online subjective cognitive and functional data is feasible. The portal has good usability as evidenced by positive study partner feedback. The portal is a potential scalable strategy for cognitive impairment screening in older adults.

Longitudinal Trajectories of the Cognitive Function Index in the A4 Study

BACKGROUND

The Anti-Amyloid in Asymptomatic Alzheimer's Disease (A4) Study failed to show a treatment benefit with solanezumab, but the longitudinal consequences of elevated amyloid were observed in study participants with objective decline on the Preclinical Alzheimer Cognitive Composite (PACC) and subjective decline on the combined Cognitive Function Index (participant + study partner CFI), during the trial period.

OBJECTIVES

We sought to expand on previous findings by comparing longitudinal patterns of participant and study partner CFI separately and their associations with the PACC stratified by baseline amyloid tertile over the course of the A4 Study.

DESIGN

Cognitively unimpaired older adult participants and their study partners were independently administered the CFI at screen prior to amyloid PET disclosure and then at 3 subsequent visits (week 48, week 168, week 240) of the study. PACC collected at visits concurrent with CFI administration were also examined longitudinally.

SETTING

The A4 Study was conducted at 67 sites in Australia, Canada, Japan, and the United States.

PARTICIPANTS

1,147 participants with elevated amyloid based on florbetapir PET were enrolled in the A4 Study and included in these analyses. 583 were on placebo and 564 were treated with solanezumab.

MEASUREMENTS

The PACC was used to assess objective cognitive performance and the CFI was used to assess change in everyday cognitive functioning by the participant and their study partner independently. Amyloid level was characterized by Centiloid tertiles (<46.1 CL, 46.1 to 77.2 CL, >77.2 CL). Participants were aware of their elevated amyloid status, but not their CL tertile, or specific level of amyloid. Longitudinal correlations between participant and study partner CFI and PACC were examined at all visits where assessments were available. The impact of baseline amyloid tertile on CFI and PACC associations was also examined.

RESULTS

Both participant and study partner CFI increased over the duration of the study indicating worsening cognitive functioning. Results did not differ by treatment group. The association between higher CFI and worse PACC for both for participant and study partner became progressively stronger over the course of the study. PACC had a significantly higher correlation with study partner CFI than with participant CFI by week 168. The stronger correlations between study partner CFI and PACC were driven by those in the highest amyloid tertile.

CONCLUSION

Both participant and study partner report captured subtle changes in everyday cognitive functioning for participants with biomarker confirmed and disclosed preclinical AD. Moreover, study partner report was most highly aligned with cognitive decline, particularly among those with the highest amyloid load.

Recent contributions to the field of subjective cognitive decline in aging: A literature review

Subjective cognitive decline (SCD) is defined as self-experienced, persistent concerns of decline in cognitive capacity in the context of normal performance on objective cognitive measures. Although SCD was initially thought to represent the "worried well," these concerns can be linked to subtle brain changes prior to changes in objective cognitive performance and, therefore, in some individuals, SCD may represent the early stages of an underlying neurodegenerative disease process (e.g., Alzheimer's disease). The field of SCD research has expanded rapidly over the years, and this review aims to provide an update on new advances in, and contributions to, the field of SCD in key areas and themes identified by researchers in this field as particularly important and impactful. First, we highlight recent studies examining sociodemographic and genetic risk factors for SCD, including explorations of SCD across racial and ethnic minoritized groups, and examinations of sex and gender considerations. Next, we review new findings on relationships between SCD and in vivo markers of pathophysiology, utilizing neuroimaging and biofluid data, as well as associations between SCD and objective cognitive tests and neuropsychiatric measures. Finally, we summarize recent work on interventions for SCD and areas of future growth in the field of SCD.

Gender of Study Partners and Research Participants Associated With Differences in Study Partner Ratings of Cognition and Activity Level

OBJECTIVES

Studies of Alzheimer's disease typically include "study partners" (SPs) who report on participants' cognition and function. Prior studies show SP reports differ depending on the relationship between the SP and participant, that is, spouse or adult child. Adult children SPs are typically female. Could differing reports be due to gender? Knowing this may help explain variability in measurement.

METHODS

The Aging, Demographics, and Memory Study enrolled a subset of participants from the Health and Retirement Study. Each participant had an SP. Bivariate and multivariable regression models compared 718 SP-participant dyads.

RESULTS

In analyses of 4 groups defined by SP and participant gender, dyads composed of 2 women were less likely to identify as White (75.8%, 95% confidence interval [CI], 70.4-80.5) than dyads composed of 2 men (93.3%, 95% CI, 81.2-97.8). In analyses adjusted for the severity of cognitive and functional impairment, women SPs rated women participants as more active than they rated men, mean 2.15 (95% CI, 2.07-2.22) versus mean 2.30 (95% CI, 2.24-2.37), respectively, on a 4-point scale. Similarly, men SPs rated women participants as more active than they rated men, mean 2.1 (95% CI, 2.0-2.2) and mean 2.4 (95% CI, 2.3-2.5), respectively. In an analysis of cognitively unimpaired participants, women SPs rated participants' memory worse than men SPs did (p < .05).

DISCUSSION

SP and participant gender influence SPs' reports of another person's cognition and activity level. Our findings expand what is understood about how nondisease factors influence measures of disease severity.

Everyday Functioning and Entorhinal and Inferior Temporal Tau Burden in Cognitively Normal Older Adults

BACKGROUND

Performance of cognitively complex "instrumental activities of daily living" (IADL) has previously been related to amyloid deposition in preclinical Alzheimer's disease.

OBJECTIVES

We aimed to investigate the relationship between IADL performance and cerebral tau accumulation in cognitively normal older adults.

DESIGN

Cross-sectional.

SETTING

Data was collected in the Anti-Amyloid Treatment in Asymptomatic Alzheimer's (A4) and Longitudinal Evaluation of Amyloid Risk and Neurodegeneration (LEARN) studies.

PARTICIPANTS

Participants (n = 447, age 71.9±4.9 years, 57.5% female) who underwent tau positron emission tomography were selected from the A4 and LEARN studies.

MEASUREMENTS

IADL performance was measured using the self- and study partner-reported versions of the Alzheimer's Disease Cooperative Study Activities of Daily Living - Prevention Instrument (ADCS ADL-PI). We also investigated discordance between participants and their study partners. Cross-sectional associations between entorhinal and inferior temporal tau (independent variables) and ADCS ADL-PI total scores, item-level scores and discordance (dependent variables) were investigated in linear and logistic regressions. Analyses were adjusted for age, sex and education and a tau by amyloid interaction was also included.

RESULTS

Participants and their study partners reported high levels of IADL performance. Entorhinal and inferior temporal tau were related to study partner but not to self-reported total ADCS ADL-PI scores. The association was not retained after adjustment for global cerebral amyloid burden. At the item level, greater entorhinal tau was associated with study partner-reported difficulties remembering important dates (odds ratio (OR) = 1.24, 95% confidence interval (95%CI) = [1.06, 1.45], p = 0.008) and difficulties remembering the details of TV programs and movies (OR = 1.32, 95%CI = [1.08, 1.61], p = 0.007). Greater inferior temporal tau was associated with self-reported difficulties managing to find personal belongings (OR = 1.23, 95%CI = [1.04, 1.46], p = 0.018) and study partner-reported difficulties remembering the details of TV programs and movies (OR = 1.39, 95%CI = [1.11, 1.75], p = 0.005). Discordance between participant and study partner-report was more likely with greater entorhinal (OR = 1.18, 95%CI = [1.05, 1.33], p = 0.005) and inferior temporal tau burden (OR = 1.29, 95%CI = [1.10, 1.51], p = 0.002).

DISCUSSION

We found a cross-sectional relationship between study partner-reported everyday functioning and tau in cognitively normal older adults. Participants were more likely to self-report difficulties differently from their study partners when tau burden was higher. This may hint at an altered early-disease awareness of functional changes and underscores the importance of self-report of IADL functioning in addition to collateral report by a study partner.

You've Got a Friend in Me: How Cognitively Unimpaired Older Adults Select a Study Partner to Participate with Them in Alzheimer's Disease Research

BACKGROUND

Participants in Alzheimer's disease (AD) prevention studies are generally required to enroll with a study partner; this requirement constitutes a barrier to enrollment for some otherwise interested individuals. Analysis of dyads enrolled in actual AD trials suggests that the study partner requirement shapes the population under study.

OBJECTIVE

To understand if individuals can identify someone to serve as their study partner and whether they would be willing to ask that individual.

METHODS

We conducted semi-structured interviews with cognitively unimpaired, English-speaking older adults who had previously expressed interest in AD research by signing up for a research registry. We also interviewed their likely study partners. Audio-recorded interviews were transcribed and coded in an iterative, team-based process guided by a content analysis approach.

RESULTS

We interviewed 60 potential research participants and 17 likely study partners. Most potential participants identified one or two individuals they would be willing to ask to serve as their study partner. Interviewees saw value in the study partner role but also understood it to entail burdens that could make participation as a study partner difficult. The role was seen as relatively more burdensome for individuals still in the workforce or with family responsibilities. Calls from the researcher to discuss the importance of the role and the possibility of virtual visits were identified as potential strategies for increasing study partner availability.

CONCLUSION

Efforts to increase recruitment, particularly representative recruitment, of participants for AD prevention studies should reduce barriers to participation by thoughtfully designing the study partner role.