How Accurately Do Patients and Their Care Partners Report Results of Amyloid-β PET Scans for Alzheimer's Disease Assessment?

Beta amyloid PET scans for dementia diagnoses: Practice and research implications from CARE-IDEAS

Beta amyloid PET scans are a minimally invasive biomarker that may inform Alzheimer's disease (AD) diagnosis. The Caregiver's Reactions and Experience (CARE) study, an IDEAS supplement, aimed to understand experiences of PET scan recipients and their care partners regarding motivations for scans, reporting and interpreting results, and impact of results. Patients with mild cognitive impairment or dementia who agreed to join the CARE-IDEAS study and their care partners participated in a baseline survey and follow-up survey approximately 18 months later, supplemented by in-depth qualitative interviews with subsets of participants. Patients who received scans and volunteered for follow-up research were more likely to be male, better educated, and have higher income than the general population. Survey information was merged with Medicare data. This article integrates findings from several CARE-IDEAS publications and provides implications for practice and research. Although most participants accurately reported scan results, they were often confused about their meaning for prognosis. Some participants reported distress with results, but there were no significant changes in measured depression, burden, or economic strain over time. Many respondents desired more information about prognosis and supportive resources. Scan results were not differentially associated with changes in service use over time. Findings suggest a need for carefully designed and tested tools for clinicians to discuss risks and benefits of scans and their results, and resources to support patients and care partners in subsequent planning. Learning of scan results provides a point-of-contact that should be leveraged to facilitate shared decision-making and person-centered longitudinal AD care.

"And Does That Necessarily Mean Absolutely Alzheimer's?" An Analysis of Questions Raised Following Amyloid PET Results Disclosure

INTRODUCTION

Amyloid PET scans provide individuals with mild cognitive impairment (MCI) information about their risk of progressing to Alzheimer's dementia (AD). Given the wide-ranging implications of this information, best practice guidelines are needed to support researchers and clinicians disclosing these high-stakes test results. To inform the development of such guidelines, this analysis aims to describe questions and concerns raised during the disclosure of amyloid PET results in the context of MCI.

METHODS

Qualitative description was performed to analyze (n = 34) transcripts of audio-recorded amyloid PET results disclosure sessions involving MCI care dyads. The analysis focused on characterizing the frequency and nature of questions raised during an open question-and-answer (Q&A) period following the return of scan results using a standardized protocol.

RESULTS

Nearly all (n = 32/34) dyads posed questions during Q&A. Questions fell within six main categories with the most common being requests for clarification regarding AD/MCI, and next steps given the result. Questions were interspersed with comments reflecting the need for emotional support. Independently administered assessments of comprehension of results showed that, following the disclosure and Q&A, 31/32 participants with MCI and 31/31 care partners scored ≥4 on a 5-point scale. The number of questions asked by care partners during Q&A positively correlated with their level of comprehension (n = 31, Spearman's r = 0.370, p = 0.040).

DISCUSSION

This analysis highlights the value of providing opportunities for patients and their family members to ask questions upon learning patients' brain amyloid status. Disclosing clinicians should be prepared to provide clarification, resources, and support to patients and families during the return of amyloid PET results.

Psychosocial and Behavioral Outcomes for Persons With Cognitive Impairment and Caregivers Following Amyloid-β PET Scan Disclosure: A Systematic Review

BACKGROUND

Positron emission tomography (PET) scans for amyloid-β can aid in the early and accurate detection of Alzheimer disease. The results of amyloid PET scans could help people with cognitive impairment and caregivers better understand their diagnosis; however, there are concerns that they could also cause psychological harm.

METHODS

A systematic review of psychosocial and behavioral quantitative outcomes following the disclosure of an amyloid PET scan for persons living with cognitive impairment (subjective cognitive decline, mild cognitive impairment, Alzheimer's Disease, and other dementias) and caregivers.

FINDINGS

Ten papers were identified from 7 studies. There was little evidence of an association between disclosure and depression. However, persons with mild cognitive impairment and their caregivers with elevated levels of amyloid had an increased risk of distress or anxiety compared with those without elevated amyloid. Participants correctly recalled the scan results; however, it is unclear whether this led to an increased understanding of their diagnosis. We did not identify any studies measuring behavioral outcomes.

CONCLUSIONS

We found mixed evidence on the relationship between amyloid scans and psychosocial and behavioral outcomes in people with cognitive impairment and caregivers. These findings highlight the need for more methodologically rigorous research on this topic.

Continuity of care (COC) and amyloid-β PET scan: the CARE-IDEAS study

BACKGROUND

High continuity of care (COC) is associated with better clinical outcomes among older adults. The impact of amyloid-β PET scan on COC among adults with mild cognitive impairment (MCI) or dementia of uncertain etiology is unknown.

METHODS

We linked data from the CARE-IDEAS study, which assessed the impact of amyloid-β PET scans on outcomes in Medicare beneficiaries with MCI or dementia of uncertain etiology and their care partners, to Medicare claims (2015-2018). We calculated a participant-level COC index using the Bice-Boxerman formula and claims from all ambulatory evaluation and management visits during the year prior to and following the amyloid-β PET scan. We compared baseline characteristics by scan result (elevated or non-elevated) using standardized differences. To evaluate changes in COC, we used multiple regression models adjusting for sociodemographics, cognitive function, general health status, and the Charlson Comorbidity Index.

RESULTS

Among the 1171 cohort members included in our analytic population, the mean age (SD) was 75.2 (5.4) years, 61.5% were male and 93.9% were non-Hispanic white. Over two-thirds (68.1%) had an elevated amyloid-β PET scan. Mean COC for all patients was 0.154 (SD = 0.102; range = 0-0.73) prior to the scan and 0.158 (SD = 0.105; range = 0-1.0) in the year following the scan. Following the scan, the mean COC index score increased (95% CI) by 0.005 (-0.008, 0.019) points more for elevated relative to not elevated scan recipients, but this change was not statistically significant. There was no association between scan result (elevated vs. not elevated) or any other patient covariates and changes in COC score after the scan.

CONCLUSION

COC did not meaningfully change following receipt of amyloid-β PET scan in a population of Medicare beneficiaries with MCI or dementia of uncertain etiology. Future work examining how care continuity varies across marginalized populations with cognitive impairment is needed.

"I know that my role is going to change": a mixed-methods study of the relationship between amyloid-β PET scan results and caregiver burden

BACKGROUND

Caregiver burden consists of disease specific and perceived stressors, respectively referred to as objective and subjective indicators of burden, and is associated with negative outcomes. Previous research has found that care partners to persons living with cognitive impairment and elevated levels of amyloid-β, as measured by a positron emission tomography (PET) scan, may experience caregiver burden.

AIMS

To elucidate the relationship between amyloid scan results and subjective and objective indicators of burden.

METHODS

A parallel mixed-methods design using survey data from 1338 care partners to persons with mild cognitive impairment (MCI) and dementia who received an amyloid scan from the CARE-IDEAS study; and semi-structured interviews with a subsample of 62 care partners. Logistic regression models were used to investigate objective factors associated with caregiver burden. A thematic analysis of semi-structured interviews was used to investigate subjective indicators by exploring care partners' perceptions of their role following an amyloid scan.

RESULTS

Elevated amyloid was not associated with burden. However, the scan result influenced participants perceptions of their caregiving role and coping strategies. Care partners to persons with elevated amyloid expected increasing responsibility, whereas partners to persons without elevated amyloid and mild cognitive impairment did not anticipate changes to their role. Care partners to persons with elevated amyloid reported using knowledge gained from the scan to develop coping strategies. All care partners described needing practical and emotional support.

CONCLUSIONS

Amyloid scans can influence subjective indicators of burden and present the opportunity to identify and address care partners' support needs.

Advance directives among cognitively impaired persons who had an amyloid PET scan and their care partners: a mixed-methods study

BACKGROUND

Little research exists on the role of β-amyloid PET scans as part of Alzheimer's diagnostic tests and documentation of end-of-life preferences for persons with cognitive impairment. The study objectives were to examine the association of amyloid PET scan results (elevated vs. not elevated amyloid levels) and diagnostic category (mild cognitive impairment vs. dementia) with the likelihood of having an advance directive (reported a median of 4.5 months post-scan); to explore perceptions of PET scan results and their influence on planning for the future among persons with cognitive impairment and their care partners.

METHODS

Sequential, explanatory mixed-methods design using data from dyads in the CARE-IDEAS study: advance directives as a factor of diagnostic category and scan result using multivariable logistic regression models; thematic analysis of semi-structured interviews with persons with cognitive impairment and care partners to explore how scan results influenced documentation of future healthcare preferences. Participants included 1784 persons with cognitive impairment and care partners from the CARE-IDEAS study, and a subsample of 100 semi-structured telephone interviews.

RESULTS

81.6% of dyads reported an advance directive. Non-Hispanic, White participants had higher rates of advance directives. There was no significant association between having an advance directive and scan results. Qualitative analysis provided insight into perceived urgency to have advance directives, evolving healthcare preferences, and the context of completing advance directives.

CONCLUSIONS

Although amyloid PET scans prompted persons with cognitive impairment and care partners to consider progressive cognitive impairment as part of evolving healthcare preferences, we found substantial variability in the perceived urgency of documentation.

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.

Amyloid-β PET Scan Results Disclosure and Care-Partner Emotional Well-Being Over Time

Background: Diagnostic tests, such as amyloid-β positron emission tomography (PET) scans, can increase appropriate therapeutic management for the underlying causes of cognitive decline. To evaluate the full utility of this diagnostic tool, information is needed on whether results from amyloid-β PET scans influence care-partner outcomes. Objective: This study examines the extent to which previous disclosure of elevated amyloid (suggestive of Alzheimer’s disease (AD) etiology) versus not-elevated amyloid (not suggestive of AD etiology) is associated with changes in care-partner wellbeing. Methods: The study used data derived from a national longitudinal survey of Medicare beneficiaries (n = 921) with mild cognitive impairment (MCI) or dementia and their care-partners. Care-partner wellbeing outcomes included depressive symptoms (PHQ-8), subjective burden (4-item Zarit burden score), and a 3-item measure of loneliness. Change was measured between 4 (Time 1) and 18 (Time 2) months after receiving the scan results. Adjusted linear regression models regressed change (Time 2-Time 1) in each outcome on scan result. Results: Care-partners were primarily white, non-Hispanic, college-educated, and married to the care recipient. Elevated amyloid was not associated with statistically significant Time 1 differences in outcomes or with statistically significant changes in depressive symptoms 0.22 (–0.18, 0.61), subjective burden 0.36 (–0.01, 0.73), or loneliness 0.15 (–0.01, 0.32) for care-partners from one time point to another. Conclusion: Given advances in AD biomarker testing, future research in more diverse samples is needed to understand the influence of scan results on care-partner wellbeing across populations.

Reactions to Amyloid PET Scan Results and Levels of Anxious and Depressive Symptoms: CARE IDEAS Study

BACKGROUND AND OBJECTIVES

Few studies have examined care partners' reactions to their loved ones receiving amyloid-β positron emission tomography (PET) scan results, which can be indicative of Alzheimer's disease. We explored care partners' reactions qualitatively, and checked the association of scan results and diagnostic category (dementia vs mild cognitive impairment [MCI]) with care partner anxious and depressive symptoms through quantitative analysis.

RESEARCH DESIGN AND METHODS

Using data from 1,761 care partners in the Caregivers' Reactions and Experience, a supplemental study of the Imaging Dementia Evidence for Amyloid Scanning study, we applied an exploratory sequential mixed-methods design and examined the reactions of 196 care partners to receiving amyloid PET scan results through open-ended interview questions. Based on the qualitative content analysis, we hypothesized there would be an association of care partners' depressive (Patient Health Questionnaire-2) and anxious (6-item State-Trait Anxiety Inventory) symptoms with scan results and diagnostic category which we then tested with logistic regression models.

RESULTS

Content analysis of open-ended responses suggests that when scan results follow the care partner's expectations, for example, elevated amyloid in persons with dementia, care partners report relief and gratitude for the information, rather than distress. Adjusted logistic regression models of survey responses support this finding, with significantly higher odds of anxiety, but not depressive symptoms, among care partners of persons with MCI versus dementia and elevated amyloid.

DISCUSSION AND IMPLICATIONS

Care partners of persons with MCI reported distress and had higher odds of anxiety after receiving elevated amyloid PET scan results than care partners of persons with dementia. This has the potential to inform clinical practice through recommendations for mental health screening and referrals.

Longitudinal Speech Biomarkers for Automated Alzheimer's Detection

We introduce a novel audio processing architecture, the Open Voice Brain Model (OVBM), improving detection accuracy for Alzheimer's (AD) longitudinal discrimination from spontaneous speech. We also outline the OVBM design methodology leading us to such architecture, which in general can incorporate multimodal biomarkers and target simultaneously several diseases and other AI tasks. Key in our methodology is the use of multiple biomarkers complementing each other, and when two of them uniquely identify different subjects in a target disease we say they are orthogonal. We illustrate the OBVM design methodology by introducing sixteen biomarkers, three of which are orthogonal, demonstrating simultaneous above state-of-the-art discrimination for two apparently unrelated diseases such as AD and COVID-19. Depending on the context, throughout the paper we use OVBM indistinctly to refer to the specific architecture or to the broader design methodology. Inspired by research conducted at the MIT Center for Brain Minds and Machines (CBMM), OVBM combines biomarker implementations of the four modules of intelligence: The brain OS chunks and overlaps audio samples and aggregates biomarker features from the sensory stream and cognitive core creating a multi-modal graph neural network of symbolic compositional models for the target task. In this paper we apply the OVBM design methodology to the automated diagnostic of Alzheimer's Dementia (AD) patients, achieving above state-of-the-art accuracy of 93.8% using only raw audio, while extracting a personalized subject saliency map designed to longitudinally track relative disease progression using multiple biomarkers, 16 in the reported AD task. The ultimate aim is to help medical practice by detecting onset and treatment impact so that intervention options can be longitudinally tested. Using the OBVM design methodology, we introduce a novel lung and respiratory tract biomarker created using 200,000+ cough samples to pre-train a model discriminating cough cultural origin. Transfer Learning is subsequently used to incorporate features from this model into various other biomarker-based OVBM architectures. This biomarker yields consistent improvements in AD detection in all the starting OBVM biomarker architecture combinations we tried. This cough dataset sets a new benchmark as the largest audio health dataset with 30,000+ subjects participating in April 2020, demonstrating for the first time cough cultural bias.