Study partner types and prediction of cognitive performance: implications to preclinical Alzheimer's trials

Understanding what aspects of Parkinson's disease matter most to patients and families

Understanding what matters to people with Parkinson's and their family is essential to derive relevant clinical outcome measures and guide clinical care. The purpose of this study was to explore what is important to people with Parkinson's disease vs. family over time. A qualitative content-analysis of online survey data collected by Parkinson's UK was conducted to identify types and frequencies of important symptoms and impacts of Parkinson's for people with the disease vs. family of people with Parkinson's. Independent T-tests were used to identify significance of between group differences for patients vs. family at < 2, 2-5, 6-10, 11-20, > 20-year durations. ANOVA was used to assess for within group differences by disease duration. We found that symptom priority changed significantly over time with longer disease duration. Tremor was reported less often later on, whereas mobility, dyskinesias, gait and speech/communication symptoms gained priority. In general, patients identified movement-related symptoms (e.g., walking, bradykinesia) as the most bothersome at all durations while family more strongly prioritized the physical and psychosocial impacts of disease (e.g., mobility, safety, interpersonal interactions, independence, and family impact). We conclude that important differences exist between family and patient perspectives of what matters and change over time with longer duration of disease.

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.

Clinical importance in Alzheimer's disease: effects of anchor agreement and disease severity

OBJECTIVES

Methods of evaluating clinically meaningful decline are critical in research on Alzheimer's disease. A common method of quantifying clinically meaningful change is to calculate an anchor-based minimal clinically important difference (MCID) score. In this approach, individuals who report a meaningful change serve as the "anchors", and the mean level of change for this group serves as the MCID. In research on Alzheimer's disease, there are several possible anchors, including patients, knowledgeable observers (e.g., a family member), and clinicians. The goal of this study was to examine the extent to which agreement among anchors impacts MCID estimation and whether this relationship is moderated by cognitive severity status.

METHODS

Analyses were completed on a longitudinal sample of 2247 adults, aged 50-103, from the Uniform Data Set. Outcome measures included the Montreal Cognitive Assessment, Clinical Dementia Rating-Sum of Boxes, and Functional Activities Questionnaire.

RESULTS

For all of the outcomes, the MCID estimate was significantly higher when meaningful decline was endorsed by all of the anchors compared to when there was disagreement among the anchors. In addition, the MCID estimate was higher with increasing severity of cognitive impairment. Finally, cognitive severity status moderated the influence of agreement among anchors on MCID estimation; as disease severity increased, anchor agreement demonstrated less influence on the MCID.

CONCLUSIONS

MCID estimates based on one anchor may underestimate meaningful change, and researchers should consider the viewpoints of multiple anchors in constructing MCIDs, particularly in the early stages of cognitive decline.

Subjective cognitive decline across ethnoracial groups in the A4 study

INTRODUCTION

The associations between subjective cognitive decline (SCD), cognition, and amyloid were explored across diverse participants in the A4 study.

METHODS

Five thousand one hundred and fifty-one non-Hispanic White, 262 non-Hispanic Black, 179 Hispanic-White, and 225 Asian participants completed the Preclinical Alzheimer Cognitive Composite (PACC), self- and study partner-reported Cognitive Function Index (CFI). A subsample underwent amyloid positron emission tomography (18 F-florbetapir) (N = 4384). We examined self-reported CFI, PACC, amyloid, and study partner-reported CFI by ethnoracial group.

RESULTS

The associations between PACC-CFI and amyloid-CFI were moderated by race. The relationships were weaker or non-significant in non-Hispanic Black and Hispanic White groups. Depression and anxiety scores were stronger predictors of CFI in these groups. Despite group differences in the types of study partners, self- and study partner-CFI were congruent across groups.

DISCUSSION

SCD may not uniformly relate to cognition or AD biomarkers in different ethnoracial groups. Nonetheless, self- and study partner-SCD were congruent despite differences in study partner type. Highlights Association between SCD and objective cognition was moderated by ethnoracial group. Association between SCD and amyloid was moderated by ethnoracial group. Depression and anxiety were stronger predictors of SCD in Black and Hispanic groups. Study-partner and self-reported SCD are congruent across groups. Study-partner report was consistent despite difference in study partner types.

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.

Optimal Weighting of Preclinical Alzheimer's Cognitive Composite (PACC) Scales to Improve their Performance as Outcome Measures for Alzheimer's Disease Clinical Trials

Introduction

Cognitive composite scales constructed by combining existing neuropsychometric tests are seeing wide application as endpoints for clinical trials and cohort studies of Alzheimer's disease (AD) predementia conditions. Preclinical Alzheimer's Cognitive Composite (PACC) scales are composite scores calculated as the sum of the component test scores weighted by the reciprocal of their standard deviations at the baseline visit. Reciprocal standard deviation is an arbitrary weighting in this context, and may be an inefficient utilization of the data contained in the component measures. Mathematically derived optimal composite weighting is a promising alternative.

Methods

Sample size projections using standard power calculation formulas were used to describe the relative performance of component measures and their composites when used as endpoints for clinical trials. Power calculations were informed by (n=1,333) amnestic mild cognitive impaired participants in the National Alzheimer's Coordinating Center (NACC) Uniform Data Set.

Results

A composite constructed using PACC reciprocal standard deviation weighting was both less sensitive to change than one of its component measures and less sensitive to change than its optimally weighted counterpart. In standard sample size calculations informed by NACC data, a clinical trial using the PACC weighting would require 38% more subjects than a composite calculated using optimal weighting.

Discussion

These findings illustrate how reciprocal standard deviation weighting can result in inefficient cognitive composites, and underscore the importance of component weights to the performance of composite scales. In the future, optimal weighting parameters informed by accumulating clinical trial data may improve the efficiency of clinical trials in AD.

Retention of Study Partners in Longitudinal Studies of Alzheimer Disease

BACKGROUND

Study partners are required for all participants at Alzheimer's Disease Research Centers (ADRCs). Study partners' attitudes and beliefs may contribute to missed visits and negatively impact retention of participants in longitudinal AD studies.

OBJECTIVE

Study partners (N = 212) of participants (Clinical Dementia Rating® [CDR]≤2) at four ADRCs were randomly surveyed to examine their facilitators and barriers to continued participation in AD studies.

METHODS

Reasons for participation were analyzed with factor analysis and regression analysis. Effects of complaints and goal fulfillment on attendance were estimated with fractional logistic models. Open-ended responses were characterized with a Latent Dirichlet Allocation topic model.

RESULTS

Study partners participated for personal benefit and altruism. They emphasized personal benefits more when their participants had a CDR > 0 than when they had a CDR = 0. This difference declined with participant age. The majority of study partners rated their ADRC participation as positive and meeting their goals. Although half reported at least one complaint, very few regretted participating. Those who reported that ADRC participation fulfilled their goals or had fewer complaints were more likely to have perfect attendance. Study partners requested more feedback about test results and better management of study visits.

CONCLUSION

Study partners are motivated by both personal and altruistic goals. The salience of each goal depends on their trust in researchers and the participant's cognitive status and age. Retention may improve with perceived goal fulfillment and fewer complaints. Potential areas for improving retention are providing more information about the participant's test results and better management of study visits.

The role of dyadic cognitive report and subjective cognitive decline in early ADRD clinical research and trials: Current knowledge, gaps, and recommendations

Efficient identification of cognitive decline and Alzheimer's disease (AD) risk in early stages of the AD disease continuum is a critical unmet need. Subjective cognitive decline is increasingly recognized as an early symptomatic stage of AD. Dyadic cognitive report, including subjective cognitive complaints (SCC) from a participant and an informant/study partner who knows the participant well, represents an accurate, reliable, and efficient source of data for assessing risk. However, the separate and combined contributions of self- and study partner report, and the dynamic relationship between the two, remains unclear. The Subjective Cognitive Decline Professional Interest Area within the Alzheimer's Association International Society to Advance Alzheimer's Research and Treatment convened a working group focused on dyadic patterns of subjective report. Group members identified aspects of dyadic-report information important to the AD research field, gaps in knowledge, and recommendations. By reviewing existing data on this topic, we found evidence that dyadic measures are associated with objective measures of cognition and provide unique information in preclinical and prodromal AD about disease stage and progression and AD biomarker status. External factors including dyad (participant-study partner pair) relationship and sociocultural factors contribute to these associations. We recommend greater dyad report use in research settings to identify AD risk. Priority areas for future research include (1) elucidation of the contributions of demographic and sociocultural factors, dyad type, and dyad relationship to dyad report; (2) exploration of agreement and discordance between self- and study partner report across the AD syndromic and disease continuum; (3) identification of domains (e.g., memory, executive function, neuropsychiatric) that predict AD risk outcomes and differentiate cognitive impairment due to AD from other impairment; (4) development of best practices for study partner engagement; (5) exploration of study partner report as AD clinical trial endpoints; (6) continued development, validation, and optimization, of study partner report instruments tailored to the goals of the research and population.

Predictors of who Serves as an Alzheimer's Disease Research Participant's Study Partner and the Impact of their Relationship on Study Partners' Reports on Participants

Background: Alzheimer's disease and Alzheimer's disease related dementias (AD/ADRD) research typically requires participants to enroll with a "study partner" (SP). Little is known about what predicts who steps into the SP role or whether the SP's relationship to the participant affects their reports of disease severity.Methods: Health and Retirement Study data (HRS), collected prior to the Aging, Demographics and Memory Study (ADAMS), was used to identify sociocultural factors that predict who serves as a SP in ADAMS. SP-reported outcomes were compared between three types of participant-SP relationships: spousal, adult child, and other.Results: Spouses (35%) and adult children (39%) were similarly likely to serve as SPs. Factors predicting who served differed. In multivariable analyses, adult children rated participants less impaired than spouses on measures of memory, judgment, and organizational abilities (p < .05). Conclusions: The participant-SP relationship has independent effects on the SP's reports of the severity of cognitive impairments.

Impact of clinical symptoms and diagnosis: the electronic Person-Specific Outcome Measure (ePSOM) development programme

Introduction

Regulatory bodies recommend that outcome measures used in Alzheimer’s disease (AD) clinical trials capture clinically meaningful changes for the trial participant. However, commonly used outcome measures do not reflect the individual’s views on what matters to them individually. The aim of the electronic Person-Specific Outcome Measure (ePSOM) programme is to better understand what outcomes matter to patients in early Alzheimer’s disease.

Methods

As part of the ePSOM programme, we designed and ran an online study to understand what matters to individuals when developing new treatments for AD. The ePSOM survey ran Aug 2019–Dec 2019 (UK) and collected primarily free text responses which were analysed using Natural Language Processing (NLP) techniques. In this paper, we focus our analyses on individuals who reported having a neurodegenerative disease diagnosis (primarily Mild Cognitive Impairment (MCI) or AD), reporting the most frequent and most important brain health priorities for this group. Due to a small sample size, the Diagnosis group was analysed as a whole. Finally, we compared the Diagnosis group to an age and gender matched control group using chi-squared tests to look for any differences between the Diagnosis and control groups’ priorities.

Results

The survey was completed by 5808 respondents, of whom 167 (2.9%) (women n = 91, men n = 69, other n = 7) had received one of our pre-defined neurodegenerative disease diagnosis: most commonly MCI n = 52, 1.1% (mean age 69.42, SD = 10.8); or Alzheimer’s disease n = 48, 1.0% (mean age 71.24, SD = 9.79). Several thematic clusters were significantly more important for the target diagnostic group, e.g.: Expressing opinions; and less important, e.g., Cognitive Games.

Conclusion

We conclude there are a range of outcomes which individuals consider important and what potential new treatments should help maintain or improve, suggesting that outcomes that matter shift along the preclinical, prodromal and overt dementia continuum. This has important implications for the development of outcome measures in long term prevention studies that last several years where participants may pass through different stages of disease. In the final stage of our project, we will design an electronic outcomes app which will employ the methodology tested in the large-scale survey to capture what matters to individuals about their brain health at an individual level.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41687-022-00433-2.

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

Whereas discrepancies between participant- and study partner-reported cognitive concerns on the Alzheimer's disease (AD) continuum have been observed, more needs to be known regarding the longitudinal trajectories of participant- vs. study partner-reported concerns, particularly their relationship to AD biomarkers and mood symptomology. Additionally, it is unclear whether years of in-clinic data collection are needed to observe relationships with AD biomarkers, or whether more frequent, remote assessments over shorter periods of time would suffice. This study primarily sought to examine the relationships between longitudinal trajectories of participant- and study partner-rated cognitive decline and baseline biomarker levels [i.e., amyloid and tau positron emission tomography (PET)], in addition to how mood symptomatology may alter these trajectories of concerns over a 2-year period. Baseline mood was associated with longitudinal participant-rated concerns, such that participants with elevated depression and anxiety scores at baseline had decreasing concerns about cognitive decline over time (fixed estimate = -0.17, 95% CI [-0.29 to -0.05], t = -2.75, df = 457, adj. p = 0.012). A significant interaction between baseline amyloid (fixed estimate = 4.07, 95% CI [1.13-7.01], t = 2.72, df = 353, adj. p = 0.026) and tau (fixed estimate = 3.50, 95% CI [0.95-6.06], t = 2.70, df = 331, adj. p = 0.030) levels was associated with increasing study partner concerns, but not participant concerns, over time. The interaction between amyloid and study partner concerns remained significant when utilizing only the first year of concern-related data collection. Overall, these results suggest that frequent, remote assessment of study partner-reported concerns may offer additional insight into the AD clinical spectrum, as study partners appear to more accurately update their concerns over time with regard to pathology, with these concerns less influenced by participants' mood symptomatology.

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.

Translation, cross-cultural adaptation, and validity of the Brazilian version of the Cognitive Function Instrument

Subjective cognitive decline (SCD) is defined as a self-perception of a progressive cognitive impairment, which is not detected objectively through neuropsychological tests. The Alzheimer's Disease Cooperative Study developed the Cognitive Function Instrument (CFI) to evaluate individuals with SCD. The CFI consists of two versions, namely, a self-report and a partner report.

Item-Level Investigation of Participant and Study Partner Report on the Cognitive Function Index from the A4 Study Screening Data

BACKGROUND

Greater subjective cognitive changes on the Cognitive Function Index (CFI) was previously found to be associated with elevated amyloid (Aß) status in participants screening for the A4 Study, reported by study partners and the participants themselves. While the total score on the CFI related to amyloid for both sources respectively, potential differences in the specific types of cognitive changes reported by either participants or their study partners was not investigated.

OBJECTIVES

To determine the specific types of subjective cognitive changes endorsed by participants and their study partners that are associated with amyloid status in individuals screening for an AD prevention trial.

DESIGN, SETTING, PARTICIPANTS

Four thousand four hundred and eighty-six cognitively unimpaired (CDR=0; MMSE 25-30) participants (ages 65-85) screening for the A4 Study completed florbetapir (Aß) Positron Emission Tomography (PET) imaging. Participants were classified as elevated amyloid (Aß+; n=1323) or non-elevated amyloid (Aß-; n=3163).

MEASUREMENTS

Prior to amyloid PET imaging, subjective report of changes in cognitive functioning were measured using the CFI (15 item questionnaire; Yes/Maybe/No response options) and administered separately to both participants and their study partners (i.e., a family member or friend in regular contact with the participant). The impact of demographic factors on CFI report was investigated. For each item of the CFI, the relationship between Aß and CFI response was investigated using an ordinal mixed effects model for participant and study partner report.

RESULTS

Independent of Aß status, participants were more likely to report 'Yes' or 'Maybe' compared to the study partners for nearly all CFI items. Older age (r= 0.06, p<0.001) and lower education (r=-0.08, p<0.001) of the participant were associated with higher CFI. Highest coincident odds ratios related to Aß+ for both respondents included items assessing whether 'a substantial decline in memory' had occurred in the last year (ORsp= 1.35 [95% CI 1.11, 1.63]; ORp= 1.55 [95% CI 1.34, 1.79]) and whether the participant had 'seen a doctor about memory' (ORsp= 1.56 [95% CI 1.25, 1.95]; ORp =1.71 [95% CI 1.37, 2.12]). For two items, associations were significant for only study partner report; whether the participant 'Repeats questions' (ORsp = 1.30 [95% CI 1.07, 1.57]) and has 'trouble following the news' (ORsp= 1.46[95% CI 1.12, 1.91]). One question was significant only for participant report; 'trouble driving' (ORp= 1.25 [95% CI 1.04, 1.49]).

CONCLUSIONS

Elevated Aβ is associated with greater reporting of subjective cognitive changes as measured by the CFI in this cognitively unimpaired population. While participants were more likely than study partners to endorse change on most CFI items, unique CFI items were associated with elevated Aß for participants and their study partners, supporting the value of both sources of information in clinical trials.