Age-adjusted CSF t-tau and NfL do not improve diagnostic accuracy for prodromal Alzheimer's disease

Cerebrospinal fluid total-tau (t-tau) and neurofilament light chain (NfL) are biomarkers of neurodegeneration and are increased in Alzheimer's disease (AD). In order to adjust for age-related increases in t-tau and NfL, cross-sectional age-adjusted norms were developed based on amyloid negative cognitively normal (CN) adults aged 41-78 years (CN, n = 137). The age-adjusted norms for t-tau and NfL did not improve receiver operating curve based diagnostic accuracies in individuals with mild cognitive impairment (MCI) due to AD (AD-MCI, n = 144). Furthermore, while NfL was correlated with higher age in AD-MCI, no significant correlation was found for t-tau. The cox proportional hazard models, applied in 429 participants with baseline t-tau and NfL, showed higher hazard ratio of progression to MCI or dementia without age-adjustments (HR = 3.39 for t-tau and HR = 3.17 for NfL), as compared to using our norms (HR = 2.29 for t-tau and HR = 1.89 for NfL). Our results indicate that utilizing normative reference data could obscure significant age-related increases in these markers associated with neurodegeneration and AD leading to a potential loss of overall diagnostic accuracy.

Recent Advances in Neuropsychological Test Interpretation for Clinical Practice

Much attention in the field of clinical neuropsychology has focused on adapting to the modern healthcare environment by advancing telehealth and promoting technological innovation in assessment. Perhaps as important (but less discussed) are advances in the development and interpretation of normative neuropsychological test data. These techniques can yield improvement in diagnostic decision-making and treatment planning with little additional cost. Brooks and colleagues (Can Psychol 50: 196-209, 2009) eloquently summarized best practices in normative data creation and interpretation, providing a practical overview of norm development, measurement error, the base rates of low scores, and methods for assessing change. Since the publication of this seminal work, there have been several important advances in research on development and interpretation of normative neuropsychological test data, which may be less familiar to the practicing clinician. Specifically, we provide a review of the literature on regression-based normed scores, item response theory, multivariate base rates, summary/factor scores, cognitive intraindividual variability, and measuring change over time. For each topic, we include (1) an overview of the method, (2) a rapid review of the recent literature, (3) a relevant case example, and (4) a discussion of limitations and controversies. Our goal was to provide a primer for use of normative neuropsychological test data in neuropsychological practice.

Longitudinal normative standards for cognitive tests and composites using harmonized data from two Wisconsin AD-risk-enriched cohorts

INTRODUCTION

Published norms are typically cross-sectional and often are not sensitive to preclinical cognitive changes due to dementia. We developed and validated demographically adjusted cross-sectional and longitudinal normative standards using harmonized outcomes from two Alzheimer's disease (AD) risk-enriched cohorts.

METHODS

Data from the Wisconsin Registry for Alzheimer's Prevention and the Wisconsin Alzheimer's Disease Research Center were combined. Quantile regression was used to develop unconditional (cross-sectional) and conditional (longitudinal) normative standards for 18 outcomes using data from cognitively unimpaired participants (N = 1390; mean follow-up = 9.25 years). Validity analyses (N = 2456) examined relationships between percentile scores (centiles), consensus-based cognitive statuses, and AD biomarker levels.

RESULTS

Unconditional and conditional centiles were lower in those with consensus-based impairment or biomarker positivity. Similarly, quantitative biomarker levels were higher in those whose centiles suggested decline.

DISCUSSION

This study presents normative standards for cognitive measures sensitive to pre-clinical changes. Future directions will investigate potential clinical applications of longitudinal normative standards.

HIGHLIGHTS

Quantile regression was used to construct longitudinal norms for cognitive tests. Poorer percentile scores were related to concurrent diagnosis and Alzheimer's disease biomarkers. A ShinyApp was built to display test scores and norms and flag low performance.

Old age or cognitive decline? Examining the usability of a mobile health app for older Australians

There is a growing literature on the role of mobile health applications (mHealth apps) in supporting older adults and the self-management of personal health. The purpose of this pilot study is to assess the usability of a government-funded mobile health app amongst older Australians and to evaluate whether cognitive function and demographic characteristics (i.e. age, gender, education) are associated with usability. A total of 28 older adults living in a regional city in Australia took part in the study. The participants were recruited using purposive sampling. Data collection instruments consisted of validated cognitive tests, task-based usability tests, and a questionnaire. The data was analyzed using non-parametric strategies. The findings of this study demonstrated that a government-funded, mHealth app was usable by older adults. Users were able to perform basic tasks in an effective and efficient manner. The hypothesis that elderly age would be significantly associated with performance on cognitive tests, as well as usability, was not supported. Performance on some cognitive tests was significantly and positively related to usability. Education and gender were not related to usability. The results suggest that traditional stereotypes surrounding aging and cognitive decline need to be reexamined.

Longitudinal trajectories of basal forebrain volume in normal aging and Alzheimer's disease

Dysfunction of the cholinergic basal forebrain (BF) system and amyloid-β (Aβ) deposition are early pathological features in Alzheimer's disease (AD). However, their association in early AD is not well-established. This study investigated the nature and magnitude of volume loss in the BF, over an extended period, in 516 older adults who completed Aβ-PET and serial magnetic resonance imaging scans. Individuals were grouped at baseline according to the presence of cognitive impairment (CU, CI) and Aβ status (Aβ-, Aβ+). Longitudinal volumetric changes in the BF and hippocampus were assessed across groups. The results indicated that high Aβ levels correlated with faster volume loss in the BF and hippocampus, and the effect of Aβ varied within BF subregions. Compared to CU Aβ+ individuals, Aβ-related loss among CI Aβ+ adults was much greater in the predominantly cholinergic subregion of Ch4p, whereas no difference was observed for the Ch1/Ch2 region. The findings support early and substantial vulnerability of the BF and further reveal distinctive degeneration of BF subregions during early AD.

The P300 Auditory Evoked Potential: A Physiological Measure of the Engagement of Cognitive Systems Contributing to Listening Effort?

OBJECTIVES

This study aimed to explore the potential of the P300 (P3b) as a physiological measure of the engagement of cognitive systems contributing to listening effort.

DESIGN

Nineteen right-handed young adults (mean age: 24.79 years) and 20 right-handed older adults (mean age: 58.90 years) with age-appropriate hearing were included. The P300 was recorded at Fz, Cz, and Pz using a two-stimulus oddball paradigm with the Flemish monosyllabic numbers "one" and "three" as standard and deviant stimuli, respectively. This oddball paradigm was conducted in three listening conditions, varying in listening demand: one quiet and two noisy listening conditions (+4 and -2 dB signal to noise ratio [SNR]). At each listening condition, physiological, behavioral, and subjective tests of listening effort were administered. P300 amplitude and latency served as a potential physiological measure of the engagement of cognitive systems contributing to listening effort. In addition, the mean reaction time to respond to the deviant stimuli was used as a behavioral listening effort measurement. Last, subjective listening effort was administered through a visual analog scale. To assess the effects of listening condition and age group on each of these measures, linear mixed models were conducted. Correlation coefficients were calculated to determine the relationship between the physiological, behavioral, and subjective measures.

RESULTS

P300 amplitude and latency, mean reaction time, and subjective scores significantly increased as the listening condition became more taxing. Moreover, a significant group effect was found for all physiological, behavioral, and subjective measures, favoring young adults. Last, no clear relationships between the physiological, behavioral, and subjective measures were found.

CONCLUSIONS

The P300 was considered a physiological measure of the engagement of cognitive systems contributing to listening effort. Because advancing age is associated with hearing loss and cognitive decline, more research is needed on the effects of all these variables on the P300 to further explore its usefulness as a listening effort measurement for research and clinical purposes.

The effect of age on the hearing-related quality of life in normal-hearing adults

INTRODUCTION

Recently, a new holistic Patient Reported Outcome Measure (PROM) to assess hearing-related quality of life was developed, named the hearing-related quality of life questionnaire for Auditory-VIsual, COgnitive and Psychosocial functioning (hAVICOP). The purpose of the current study was to evaluate if the hAVICOP is sufficiently sensitive to detect an age effect in the hearing-related quality of life.

METHODS

One-hundred thirteen normal-hearing participants (mean age: 42.13; range: 19 to 69 years) filled in the entire hAVICOP questionnaire online through the Research Electronic Data Capture surface. The hAVICOP consists of 27 statements, across three major subdomains (auditory-visual, cognitive, and psychosocial functioning), which have to be rated on a visual analogue scale ranging from 0 (rarely to never) to 100 (almost always). Mean scores were calculated for each subdomain separately as well as combined within a total score; the worse one's hearing-related quality of life, the lower the score. Linear regression models were run to predict the hAVICOP total as well as the three subdomain scores from age and sex.

RESULTS

A significant main effect of age was observed for the total hAVICOP and all three subdomain scores, indicating a decrease in hearing-related quality of life with increasing age. For none of the analyses, a significant sex effect was found.

CONCLUSION

The hAVICOP is sufficiently sensitive to detect an age effect in the hearing-related quality of life within a large group of normal-hearing adults, emphasizing its clinical utility. This age effect on the hearing-related quality of life might be related to the interplay of age-related changes in the bottom-up and top-down processes involved during speech processing.

Sensitivity of Individual and Composite Test Scores from the Cogstate Brief Battery to Mild Cognitive Impairment and Dementia Due to Alzheimer's Disease

BACKGROUND

The Cogstate Brief Battery (CBB) is a computerized cognitive test battery used commonly to identify cognitive deficits related to Alzheimer's disease (AD). However, AD and normative samples used to understand the sensitivity of the CBB to AD in the clinic have been limited, as have the outcome measures studied.

OBJECTIVE

This study investigated the sensitivity of CBB outcomes, including potential composite scores, to cognitive impairment in mild cognitive impairment (MCI) and dementia due to AD, in carefully selected samples.

METHODS

Samples consisted of 4,871 cognitively unimpaired adults and 184 adults who met clinical criteria for MCI (Clinical Dementia Rating (CDR) = 0.5) or dementia (CDR > 0.5) due to AD and CBB naive. Speed and accuracy measures from each test were examined, and theoretically- and statistically-derived composites were created. Sensitivity and specificity of classification of cognitive impairment were compared between outcomes.

RESULTS

Individual CBB measures of learning and working memory showed high discriminability for AD-related cognitive impairment for CDR 0.5 (AUCs ∼ 0.79-0.88), and CDR > 0.5 (AUCs ∼ 0.89-0.96) groups. Discrimination ability for theoretically derived CBB composite measures was high, particularly for the Learning and Working Memory (LWM) composite (CDR 0.5 AUC = 0.90, CDR > 0.5 AUC = 0.97). As expected, statistically optimized linear composite measures showed strong discrimination abilities albeit similar to the LWM composite.

CONCLUSIONS

In older adults, the CBB is effective for discriminating cognitive impairment due to MCI or AD-dementia from unimpaired cognition with the LWM composite providing the strongest sensitivity.

Consideration of different scoring approaches for a verbal incidental learning measure from the WAIS-IV using hippocampal volumes

Objective: While Spencer's verbal incidental learning (IL) task-from Vocabulary and Similarities subtests of the WAIS-has been validated relative to traditional memory measures and Alzheimer's disease (AD) pathology, the effectiveness of the particular scoring method used has not been assessed relative to alternative scoring weightings. The purpose of this study was to compare original and alternative scoring methods of this IL task by using an AD biomarker-benchmark to arrive at an optimal approach. Methods: Fifty-five memory-clinic patients aged 59-87 received neuropsychological assessment, measures of IL, and quantitative brain imaging. Partial correlation coefficients with total hippocampal volume-controlling for age, sex, and intracranial volume-were assessed across several IL scoring methods, and partial correlations with measures of memory were examined to evaluate convergent validity.Results: IL scoring methods maximizing the contribution of paired-associate-recall-performance were significantly correlated with both hippocampal volumes and traditional memory measures, whereas discrimination-emphasized scoring methods were not.Conclusions: IL scoring methods emphasizing memory paired-associate recall appeared to be preferable to those emphasizing memory discrimination. Administration of the IL- Similarities subtest alone, without IL- Vocabulary, may strike a balance between strength of relationships with both hippocampal volumes and standard memory measures, while also limiting administration time.

Reference Data for Attentional, Executive, Linguistic, and Visual Processing Tests Obtained from Cognitively Healthy Individuals with Normal Alzheimer's Disease Cerebrospinal Fluid Biomarker Levels

BACKGROUND

Conventional neuropsychological norms likely include cognitively unimpaired (CU) individuals with preclinical Alzheimer's disease (AD) pathology (amyloid-β, tau, and neurodegeneration) since they are based on cohorts without AD biomarkers data. Due to this limitation, population-based norms would lack sensitivity for detecting subtle cognitive decline due to AD, the transitional stage between healthy cognition and mild cognitive impairment. We have recently published norms for memory tests in individuals with normal cerebrospinal fluid (CSF) AD biomarker levels.

OBJECTIVE

The aim of the present study was to provide further AD biomarker-based cognitive references covering attentional, executive function, linguistic, and visual processing tests.

METHODS

We analyzed 248 CU individuals aged between 50-70 years old with normal CSF Aβ, p-tau, and neurodegeneration (t-tau) biomarker levels. The tests included were the Trail Making Test (TMT), Semantic Fluency Test, Digit and Symbol Span, Coding, Matrix Reasoning, Judgement of Line Orientation and Visual Puzzles. Normative data were developed based on regression models adjusted for age, education, and sex when needed. We present equations to calculate z-scores, the corresponding normative percentile tables, and online calculators.

RESULTS

Age, education, and sex were associated with performance in all tests, except education for the TMT-A, and sex for the TMT-B, Coding, and Semantic Fluency. Cut-offs derived from the current biomarker-based reference data were higher and more sensitive than standard norms.

CONCLUSION

We developed reference data obtained from individuals with evidence of non-pathologic AD biomarker levels that may improve the objective characterization of subtle cognitive decline in preclinical AD.

Loneliness and Cognitive Function in Older Adults Without Dementia: A Systematic Review and Meta-Analysis

BACKGROUND

Loneliness has been highlighted as a risk factor for dementia. However, the nature of the relationship between loneliness and cognitive function prior to onset of dementia is unclear.

OBJECTIVE

The aim of this systematic review and meta-analysis was to examine the relationship between loneliness and cognitive function in samples screened for dementia at study commencement.

METHODS

Five electronic databases (PubMed, PsycNET, Web of Science, EBSCOhost, Scopus) were searched from inception to August 31, 2021. A narrative review and random-effects meta-analysis were conducted on studies meeting search criteria. PROSPERO registration number: CRD42020155539.

RESULTS

The sixteen studies that met inclusion criteria involved 30,267 individuals, with mean age ranging from 63.0 to 84.9 years. Studies varied in dementia screening criteria, measurement of loneliness and cognitive function, and statistical modeling approach. The narrative review indicated that loneliness was associated with poorer global cognition, episodic memory, working memory, visuospatial function, processing speed, and semantic verbal fluency. Results of the meta-analysis indicated that loneliness was negatively associated with global cognitive function (overall r = -0.08; 95% CI = -0.14, -0.02; n = 6). Due to lack of sufficient data and heterogeneity between studies, we were unable to explore associations with other cognitive domains or longitudinal associations.

CONCLUSION

Loneliness is associated with subtle impairment across multiple cognitive domains in older adults who were screened for dementia. Better characterization of this relationship will provide important information about how loneliness contributes to the clinical and pathological sequalae of AD and be informative for risk reduction and early detection strategies.

Reliability, Validity, and User-Experience of Remote Unsupervised Computerized Neuropsychological Assessments in Community-Living 55- to 75-Year-Olds

BACKGROUND

Self-administered computerized neuropsychological assessments (CNAs) provide lower cost, more accessible alternatives to traditional in-person assessments but lack critical information on psychometrics and subjective experience of older adults in remote testing environments.

OBJECTIVE

We used an online brief battery of computerized tasks selected from the Cogstate Brief Battery (CBB) and Cambridge Brain Sciences (CBS) to 1) determine test-retest reliability in an unsupervised setting; 2) examine convergent validity with a comprehensive 'gold standard' paper-and-pencil neuropsychological test battery administered in-person; and 3) explore user-experience of remote computerized testing and individual tests.

METHODS

Fifty-two participants (mean age 65.8±5.7 years) completed CBB and CBS tests on their own computer, unsupervised from home, on three occasions, and visited a research center for an in-person paper-and-pencil assessment. They also completed a user-experience questionnaire.

RESULTS

Test-retest reliabilities varied for individual measures (ICCs = 0.20 to 0.83). Global cognition composites showed excellent reliability (ICCs > 0.8 over 1-month follow-up). A strong relationship between a combination of CNA measures and paper-and-pencil battery was found (canonical correlation R = 0.87, p = 0.04). Most tests were rated as enjoyable with easy-to-understand instructions. Ratings of general experience with online testing were mostly favorable; few had difficulty concentrating (17%) or using the computer for tasks (10%), although over one-third experienced performance anxiety (38%).

CONCLUSION

A combined brief online battery selected from two CNAs demonstrated robust psychometric standards for reliability (global composite), and convergent validity with a gold standard battery, and mostly good usability and acceptability in the remote testing environment.

Demographically-corrected normative data for the RBANS learning ratio in a sample of older adults

BACKGROUND

A novel learning slope score - the Learning Ratio (LR) - has recently been developed that appears to be sensitive to memory performance and AD pathology more optimally than traditional learning slope calculations. While promising, this research to date has been both experimental and based on group differences, and therefore does not aid in the interpretation of individual LR performance for either clinical or research settings. The objective of the current study was to develop demographically-corrected normative data on these LR learning slopes on verbal learning measures from the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS).

METHOD

The current study examined the influence of age and education on LR metrics for the List Learning, Story Memory, and an Aggregated RBANS score in 200 cognitively intact adults aged 65 or older using linear regression.

RESULTS

Age and education correlated with most LR metrics, but no sex differences were observed. Linear regression permitted the prediction of LR values from age and education, which are then compared to observed LR values. The result is demographically-corrected T scores for these LR metrics.

CONCLUSIONS

By comparing observed and predicted LR scores calculated from regression-based prediction equations, this represents the first step towards interpretation of individual performances on this metric for clinical decision making and treatment planning purposes. With future replication in diverse and heterogenous samples, we hope to offer a new clinical tool for the examination of learning slopes in older adults.

Relationship between a novel learning slope metric and Alzheimer's disease biomarkers

The Learning Ratio (LR) is a novel learning score examining the proportion of information learned over successive learning trials relative to information available to be learned. Validation is warranted to understand LR's sensitivity to Alzheimer's disease (AD) pathology. One-hundred twenty-three participants across the AD continuum underwent memory assessment, quantitative brain imaging, and genetic analysis. LR scores were calculated from the HVLT-R, BVMT-R, RBANS List Learning, and RBANS Story Memory, and compared to total hippocampal volumes,18F-Flutemetamol composite SUVR uptake, and APOE ε4 status. Lower LR scores were consistently associated with smaller total hippocampal volumes, greater cerebral β-amyloid deposition, and APOE ε4 positivity. This LR score outperformed a traditional learning slope calculation in all analyses. LR is sensitive to AD pathology along the AD continuum - more so than a traditional raw learning score - and reducing the competition between the first trial and subsequent trials can better depict learning capacity.

Validation of one-year reliable change in the RBANS for community-dwelling older adults with amnestic mild cognitive impairment

Objective: The current study sought to externally validate previously published standardized regression-based (SRB) equations for the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Indexes administered twice over a one-year period. Method: Hammers and colleagues' SRB prediction equations were applied to two independent samples of community-dwelling older adults with amnestic Mild Cognitive Impairment (MCI), including those recruited from the community (n = 64) and those recruited from a memory disorders clinic (n = 58). Results: While Observed Baseline and Observed Follow-up performances were generally comparable for both MCI samples over one year, both samples possessed significantly lower Observed One-Year Follow-up scores than were predicted based on Hammers and colleagues' development sample across many RBANS Indexes. Relatedly, both amnestic MCI samples possessed a greater percentage of participants either "declining" or failing to exhibit a long-term practice effect over one year relative to expectation across most Indexes. Further, the clinic-recruited amnestic MCI sample displayed worse baseline performances, smaller long-term practice effects, and greater proportions of individual participants exhibiting a decline across one year relative to the community amnestic MCI sample. Conclusions: These findings validate Hammers and colleagues' SRB prediction equations by (1) indicating their ability to identify clinically meaningful change across RBANS Indexes in independent samples, and (2) discriminating rates of cognitive change among cognitively nuanced samples.

Validation of and Demographically Adjusted Normative Data for the Learning Ratio Derived from the RAVLT in Robustly Intact Older Adults

BACKGROUND

The learning ratio (LR) is a novel learning slope score that was developed to identify learning more accurately by considering the proportion of information learned after the first trial of a multi-trial learning task. Specifically, LR is the number of items learned after trial one divided by the number of items yet to be learned. Although research on LR has been promising, convergent validation, clinical characterization, and demographic norming of this LR metric are warranted to understand its clinical utility when derived from the Rey Auditory Verbal Learning Test (RAVLT).

METHOD

Data from 674 robustly cognitively intact older participants from the Alzheimer's Disease Neuroimaging Initiative (aged 54- 89) were used to calculate the LR metric. Comparison of LR's relationship with standard memory measures was undertaken relative to other traditional learning slope metrics. In addition, retest reliability at 6, 12, and 24 months was examined, and demographically adjusted normative comparisons were developed.

RESULTS

Lower LR scores were associated with poorer performances on memory measures, and LR scores outperformed traditional learning slope calculations across all analyses. Retest reliability exceeded acceptability thresholds across time, and demographically adjusted normative equations suggested better performance for cognitively intact participants than those with mild cognitive impairment.

CONCLUSIONS

These results suggest that this LR score possesses sound retest reliability and can better reflect learning capacity than traditional learning slope calculations. With the added development and validation of regression-based normative comparisons, these findings support the use of the RAVLT LR as a clinical tool to inform clinical decision-making and treatment.

Validation of HVLT-R, BVMT-R, and RBANS Learning Slope Scores along the Alzheimer's Continuum

BACKGROUND

The learning ratio (LR) is a novel learning slope score that has been developed to reduce the inherent competition between the first trial and subsequent trials in traditional learning slopes. In essence, the LR is the number of items learned after the first trial divided by the number of items yet to be learned. Criterion and convergent validation of this LR score is warranted to understand its sensitivity along the Alzheimer's disease (AD) continuum.

METHOD

The LR metric was calculated for 123 participants from standard measures of memory, including the Hopkins Verbal Learning Test-Revised, Brief Visuospatial Memory Test-Revised, Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) list learning, and RBANS story memory. All participants were categorized as normal cognition, mild cognitive impairment (MCI), or AD. LR performances were compared between groups, among other standard memory measures, and with regards to how well they discriminated cognitively impaired from unimpaired samples-and within diagnostic subgroups.

RESULTS

Lower LR scores were observed for the MCI and AD groups than the normal cognition group, with the AD group performing worse than the MCI group for several slope calculations. Lower LR scores were also consistently associated with poorer performances on traditional memory measures. LR scores further displayed excellent receiver operator characteristics when differentiating those with and without cognitive impairment-and MCI from normal cognition. Overall, LR scores consistently outperformed traditional learning slope calculations across all analyses.

CONCLUSIONS

This LR score is sensitive to memory dysfunction along the AD continuum, and results offer criterion and convergent validity for use of the LR metric to understand learning capacity.

A Paradox in Digital Memory Assessment: Increased Sensitivity With Reduced Difficulty

The One Card Learning Test (OCL80) from the Cogstate Brief Battery-a digital cognitive test used both in-person and remotely in clinical trials and in healthcare contexts to inform health decisions-has shown high sensitivity to changes in memory in early Alzheimer's disease (AD). However, recent studies suggest that OCL sensitivity to memory impairment in symptomatic AD is not as strong as that for other standardized assessments of memory. This study aimed to improve the sensitivity of the OCL80 to AD-related memory impairment by reducing the test difficultly (i.e., OCL48). Experiment 1 showed performance in healthy adults improved on the OCL48 while the pattern separation operations that constrain performance on the OCL80 were retained. Experiment 2 showed repeated administration of the OCL48 at short retest intervals did not induce ceiling or practice effects. Experiment 3 showed that the sensitivity of the OCL48 to AD-related memory impairment (Glass's Δ = 3.11) was much greater than the sensitivity of the OCL80 (Glass's Δ = 1.94). Experiment 4 used data from a large group of cognitively normal older adults to calibrate performance scores between the OCL80 and OCL48 using equipercentile equating. Together these results showed the OCL48 to be a valid and reliable test of learning with greater sensitivity to memory impairment in AD than the OCL80.

Regression-Based Normative Data for Independent and Cognitively Active Spanish Older Adults: Digit Span, Letters and Numbers, Trail Making Test and Symbol Digit Modalities Test

In this work, we developed normative data for the neuropsychological assessment of independent and cognitively active Spanish older adults over 55 years of age.

METHOD

Regression-based normative data were calculated from a sample of 103 non-depressed independent community-dwelling adults aged 55 or older (67% women). Raw data for Digit Span (DS), Letters and Numbers (LN), the Trail Making Test (TMT), and the Symbol Digit Modalities Test (SDMT) were regressed on age, sex, and education. The model predicting TMT-B scores also included TMT-A scores. Z-scores for the discrepancy between observed and predicted scores were used to identify low scores. The base rate of low scores for SABIEX normative data was compared to the base rate of low scores using published normative data obtained from the general population.

RESULTS

The effects of age, sex, and education varied across neuropsychological measures. Although the proportion of low scores was similar between normative datasets, there was no agreement in the identification of cognitively impaired individuals.

CONCLUSIONS

Normative data obtained from the general population might not be sensitive to identify low scores in cognitively active older adults, incorrectly classifying them as cognitively normal compared to the less-active population. We provide a friendly calculator for use in neuropsychological assessment in cognitively active Spanish people aged 55 or older.

Preliminary Validation of the Learning Ratio for the HVLT-R and BVMT-R in Older Adults

BACKGROUND

The learning slope is typically represented as the raw difference between the final score and the score of the first learning trial. A new method for calculating the learning slope, the learning ratio (LR), was recently developed; it is typically represented as the number of items that are learned after the first trial divided by the number of items that are yet to be learned.

OBJECTIVE

To evaluate the convergent and criterion validity of the LR in order to understand its sensitivity to Alzheimer disease (AD) pathology.

METHOD

Fifty-six patients from a memory clinic underwent standard neuropsychological assessment and quantitative brain imaging. LR scores were calculated from the Hopkins Verbal Learning Test-Revised and the Brief Visuospatial Memory Test-Revised and were compared with both standard memory measures and total hippocampal volumes, as well as between individuals with AD and those with mild cognitive impairment.

RESULTS

Lower LR scores were consistently associated with poorer performances on standard memory measures and smaller total hippocampal volumes, generally more so than traditional learning slope scores. The LR scores of the AD group were smaller than those of the group with mild cognitive impairment. Furthermore, the aggregation of LR scores into a single metric was partially supported.

CONCLUSION

The LR is sensitive to AD pathology along the AD continuum. This result supports previous claims that the LR score can reflect learning capacity better than traditional learning calculations can by considering the amount of information that is learned at trial 1.

Validation and Norms for a Recognition Task for the Spanish Version of the Free and Cued Selective Reminding Test

OBJECTIVE

The aim of the present work was to develop and validate a recognition task to be used with the Spanish version of the 16 items Free and Cued Selective Reminding Test (FCSRT).

METHOD

A total of 96 (67.7% women) cognitively healthy, functionally independent community-dwelling participants aged 55 years or older underwent a comprehensive neuropsychological assessment. A recognition task for the FCSRT was developed that included the original 16 items, 16 semantically related items, and eight unrelated foils. Indices of discriminability (d') and response bias (C), as well as 95% confidence intervals for chance-level responding were calculated.

RESULTS

On average, our sample was 65.71 years old (SD = 6.68, range: 55-87), had 11.39 years of formal education (SD = 3.37, range: 3-19), and a Mini-Mental State Examination score = 28.42 (SD = 1.49, range: 25-30). Recognition scores did not differ statistically between sexes, nor did they correlate with demographics. Participants scored at ceiling levels (mean number of Hits = 15.52, SD = 0.906, mean number of False Alarms = 0.27, SD = 0.589). All the participants scored above chance levels.

CONCLUSIONS

Normative data from a novel recognition task for the Spanish version of the FCSRT are provided for use in clinical and research settings. Including a recognition task in the assessment of memory functioning might help uncover the pattern of memory impairments in older adults, and can help improve the memory profile of people with amnestic Mild Cognitive Impairment. Future research is warranted to validate and expand the recognition task.

An Auditory Stroop Test to Implement in Cognitive Hearing Sciences: Development and Normative Data

Objective:

This study developed and gained insight in an auditory Stroop test, implementable in cognitive hearing sciences.

Methods:

An auditory Stroop test was developed and performed in 178 participants, aged between 18 and 69 years. This Auditory Stroop test consisted of two tests: Stroop-tones and Stroop-words whereby the pitch of pure-tones and spoken words (i.e., the words high and low) had to be identified by high or low, respectively. An interference score was calculated as a measure of verbal executive functioning. Regression models were conducted to examine the effect of age, sex, education, awakeness, hearing, as well as visual and verbal working memory, and processing speed on the auditory Stroop scores. Normative data were obtained per age decade.

Results:

Compared to the visual counterparts, the auditory Stroop outcomes were better predicted by verbal working memory and processing speed. A trend was observed showing a decrease in performances with increasing age. No other participant-related variables had a significant relationship with the auditory Stroop test.

Conclusion:

This auditory Stroop test was considered a good test for measuring executive functioning using auditory stimuli. Implementing this auditory Stroop test within cognitive hearing sciences will contribute to unravel the auditory-cognitive perspective of speech understanding.

Physical fitness mediates the association between age and cognition in healthy adults

BACKGROUND

Physical fitness is an important contributor to healthy aging that improves cognition. Older adults who engage in cardiorespiratory fitness activities show less cognitive decline.

AIMS

To examine whether physical fitness acts as a potential protective mechanism shielding against the negative associations between age and cognition. Specifically, we examined whether physical fitness mediates the relationship between age and processing speed.

METHODS

114 (M = 63.80, SD = 10.63) senior executives completed a computerized cognitive battery composed of four processing speed tasks. Level of physical fitness was assessed on a treadmill stress test and reported in metabolic equivalents (METs).

RESULTS

Older age was associated with slower processing speed (r = 0.25, p = 0.007), whereas greater physical fitness was associated with faster processing speed (r = -0.30, p = 0.001). Path analysis indicated that the association between age and processing speed was fully mediated by the level of physical fitness (Indirect effect: β = 0.10, p = 0.008; Direct effect: β = 0.16, p = 0.20).

CONCLUSIONS AND DISCUSSION

The findings indicate that physical fitness is a strong mediator of the relationship between age and processing speed and imply that physical fitness makes a major contribution to cognitive reserve during the aging process. The results may suggest that the decrease in physical fitness during aging may partially account for slower cognitive processing.

Validation of one-week reliable change methods in cognitively intact community-dwelling older adults

OBJECTIVE

Reliable change methods can assist the determination of whether observed changes in performance are meaningful. The current study sought to validate previously published standardized regression-based (SRB) equations for commonly administered cognitive tests using a cognitively intact sample of older adults, and extend findings by including relevant demographic and test-related variables known to predict cognitive performance. Method: This study applied previously published SRB prediction equations to 107 cognitively intact older adults assessed twice over one week. Prediction equations were also updated by pooling the current validation sample with 93 cognitively intact participants from original development sample to create a combined development sample. Results: Significant improvements were seen between observed baseline and follow-up scores on most measures. However, few differences were seen between observed follow-up scores and those predicted from these SRB algorithms, and the level of practice effects observed based on these equations were consistent with expectations. When SRBs were re-calculated from this combined development sample, predicted follow-up scores were mostly comparable with these equations, but standard errors of the estimate were consistently smaller. Conclusions: These results help support the validity of of these SRB equations to predict cognitive performance on these measures when repeated administration is necessary over short intervals. Findings also highlight the utility of expanding SRB models when predicting follow-up performance serially to provide more accurate assessment of reliable change at the level of the individual. As short-term practice effects are shown to predict cognitive performance annually, they possess the potential to inform clinical decision-making about individuals along the Alzheimer's continuum.

Is heart failure with preserved ejection fraction a 'dementia' of the heart?

Heart failure with preserved ejection fraction (HFpEF) remains an elusive entity, due to its heterogeneous clinical profile and an arbitrarily defined nosology. Several pathophysiological mechanisms recognized as central for the development of HFpEF appear to be in common with the process of physiological aging of the heart. Both conditions are characterized by progressive impairment in cardiac function, accompanied by left ventricular hypertrophy, diastolic dysfunction, sarcomeric, and metabolic abnormalities. The neurological paradigm of dementia-intended as a progressive, multifactorial organ damage with decline of functional reserve, eventually leading to irreversible dysfunction-is well suited to represent HFpEF. In such perspective, certain phenotypes of HFpEF may be viewed as a maladaptive response to environmental modifiers, causing premature and pathological aging of the heart. We here propose that the 'HFpEF syndrome' may reflect the interplay of adverse structural remodelling and erosion of functional reserve, mirroring the processes leading to dementia in the brain. The resulting conceptual framework may help advance our understanding of HFpEF and unravel potential therapeutical targets.

Demographically-corrected normative data for the HVLT-R, BVMT-R, and Aggregated Learning Ratio values in a sample of older adults

Background: The Learning Ratio (LR) is a novel learning slope score that has been developed to reduce the inherent competition between the first trial and subsequent trials in traditional learning slopes. Recent findings suggest that LR is sensitive to AD pathology along the AD continuum - more so than the traditional learning calculations that employ raw changes across trials. However, research is still experimental and not yet directly applicable to clinical settings. Consequently, the objective of the current study was to develop demographically-corrected normative data on these LR learning slopes.Method: The current study examined the influence of age and education on LR scores for the HVLT-R, BVMT-R, and an Aggregated HVLT-R/BVMT-R in 200 cognitively intact adults aged 65 years and older using linear regression.Results: Age negatively correlated with all LR metrics, and education positively correlated with most. No sex differences were identified. LR values were predicted from age and education, which can be compared to observed LR values and converted into demographically-corrected T scores.Conclusions: By comparing observed and predicted LR scores calculated from regression-based prediction equations, interpretations are permitted that aid in clinical decision making and treatment planning. Co-norming of the HVLT-R and BVMT-R also allows for comparisons between verbal and visual learning slope scores in individual patients. We hope normative data for LR enhances its utility as a clinical tool for examining learning slopes in older adults administered the HVLT-R and/or BVMT-R.

The Effect of Cognition on the Aided Benefit in Terms of Speech Understanding and Listening Effort Obtained With Digital Hearing Aids: A Systematic Review

Purpose Hearing aids are the primary rehabilitation devices used to compensate for presbycusis, though large intersubject variability in hearing aid benefit has been reported. This systematic review aimed to investigate how intersubject differences in cognition could influence the aided benefit for speech understanding and listening effort with bilateral digital hearing aids. Method Articles were selected through systematic searches in MEDLINE, Embase, Central, and reference lists. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. Results The initial search resulted in 1,092 unique hits, of which 16 were included. The effect of cognition on the aided benefit in terms of speech understanding and listening effort was examined in 12 and four studies, respectively. The aided speech and listening effort benefit obtained from hearing aid use in general or from a specific digital feature (i.e., microphone directionality, noise reduction, amplitude compression, and frequency compression) was associated with four cognitive functions (i.e., working memory, processing speed, selective attention, and executive functions). Conclusions Hearing aid users with poorer cognitive functioning derived more aided benefit in terms of speech understanding from hearing aid settings facilitating the matching process between the incoming auditory signal and representations stored in long-term memory. However, since the number of included studies was limited, this trend should be interpreted with caution. Supplemental Material https://doi.org/10.23641/asha.13626509.

Normative Data for the ELSA-Brasil Neuropsychological Assessment and Operationalized Criterion for Cognitive Impairment for Middle-Aged and Older Adults

OBJECTIVES

Normative data should consider sociodemographic diversity for the accurate diagnosis of cognitive impairment. This study aims to provide normative data for a brief neuropsychological battery and present diagnostic criteria for cognitive impairment that could be used in primary care settings.

METHODS

We selected 9618 Brazilian middle-aged and older adults after detailed exclusion criteria to avoid subtle cognitive impairment. We analyzed age, sex, and education influence on cognitive performance. To verify the evidence of criterion validity, we compared the cognitive performance of subjects with and without a depressive episode. Additionally, we verified the percentage of spurious scores under three different cutoffs.

RESULTS

Age and education had the greatest impact on cognition. Normative scores were provided according to age and education groups. Participants with a depressive episode performed poorer than control subjects. The clinical cutoff of at least two scores below the 7th percentile revealed the adequate percentage of spurious and possible clinical performance.

CONCLUSIONS

The Longitudinal Study on Adult Health (ELSA-Brasil) provided normative data based on a unique selected set of cognitively normal subjects. Normative groups were selected based on age and education, and the battery was sensitive to the presence of a depressive episode. We suggested clinical cutoffs for the tests in this battery that could be used in primary care settings to improve the accurate diagnosis of cognitive impairment.

Superior Memory Reduces 8-year Risk of Mild Cognitive Impairment and Dementia But Not Amyloid β-Associated Cognitive Decline in Older Adults

OBJECTIVE

To prospectively examine 8-year risk of clinical disease progression to mild cognitive impairment (MCI)/dementia in older adults ≥60 with superior episodic memory (SuperAgers) compared to those cognitively normal for their age (CNFA). Additionally, to determine the extent to which SuperAgers were resilient to the negative effects of elevated amyloid-beta (Aβ+) on cognition.

METHOD

Participants were classified as SuperAgers based on episodic memory performance consistent with younger adults aged 30-44 and no impairment on non-memory tests (n = 179), and were matched with CNFA on age, sex, education, and follow-up time (n = 179). Subdistribution hazard models examined risk of clinical progression to MCI/dementia. Linear mixed models assessed the effect of Aβ on cognition over time.

RESULTS

Prevalence of Aβ+ and APOE ε4 was equivalent between SuperAgers and CNFA. SuperAgers had 69%-73% reduced risk of clinical progression to MCI/dementia compared to CNFA (HR: 0.27-0.31, 95% CI: 0.11-0.73, p < .001). Aβ+ was associated with cognitive decline in verbal memory and executive function, regardless of SuperAger/CNFA classification. In the absence of Aβ+, equivalent age-related changes in cognition were observed between SuperAgers and CNFA.

CONCLUSIONS

SuperAgers displayed resilience against clinical progression to MCI/dementia compared to CNFA despite equivalent risk for Alzheimer's disease (AD); however, SuperAgers had no greater protection from Aβ+ than CNFA. The deleterious effects of Aβ on cognition persist regardless of baseline cognitive ability. Thus, superior cognitive performance does not reflect resistance against the neuropathological processes associated with AD, and the observed resilience for SuperAgers may instead reflect neuropsychological criteria for cognitive impairment.

Normative Data for Derived Measures and Discrepancy Scores for the Uniform Data Set 3.0 Neuropsychological Battery

OBJECTIVE

The Uniform Data Set 3.0 (UDS 3.0) neuropsychological battery is a recently published battery intended for clinical research with older adult populations. While normative data for the core measures has been published, several additional discrepancy and derived scores can also be calculated. We present normative data for Trail Making Test (TMT) A & B discrepancy and ratio scores, semantic and phonemic fluency discrepancy scores, Craft Story percent retention score, Benson Figure percent retention score, difference between verbal and visual percent retention, and an error index.

METHOD

Cross-Sectional data from 1803 English speaking, cognitively normal control participants were obtained from the NACC central data repository.

RESULTS

Descriptive information for derived indices is presented. Demographic variables, most commonly age, demonstrated small but significant associations with the measures. Regression values were used to create a normative calculator, made available in a downloadable supplement. Statistically abnormal values (i.e., raw scores corresponding to the 5th, 10th, 90th, and 95th percentiles) were calculated to assist in practical application of normative findings to individual cases. Preliminary validity of the indices are demonstrated by a case study and group comparisons between a sample of individuals with Alzheimer's (N = 81) and Dementia with Lewy Bodies (DLB; N = 100).

CONCLUSIONS

Clinically useful normative data of such derived indices from the UDS 3.0 neuropsychological battery are presented to help researchers and clinicians interpret these scores, accounting for demographic factors. Preliminary validity data is presented as well along with limitations and future directions.

Generalizability of reliable change equations for the RBANS over one year in community-dwelling older adults

Objective: Reliable change methods can assist neuropsychologists in determining whether observed changes in a patient's performance are clinically meaningful. The current study sought to validate previously published standardized regression-based (SRB) equations for the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) Indexes and subtests.Methods: Duff and colleagues's SRB prediction equations, developed from 223 cognitively intact primary care patients, were applied to an independent sample of robustly cognitively intact (n = 129) community-dwelling older adults assessed with the RBANS twice over a one-year period.Results: Results suggest that the cognitively intact participants in the current validation sample possessed significantly better Observed Follow-up scores than was predicted based on Duff's developmental sample across most RBANS Indexes and many RBANS subtests, though significantly lower Observed Follow-up scores were observed for the Visuospatial/Constructional Index than was predicted. As a result of these findings, the current study calculated updated prediction algorithms for the RBANS Index and subtest scores from the sample of 129 cognitively intact participants.Conclusions: Duff's 2004 and 2005 SRB prediction equations for the RBANS Index and subtest scores failed to generalize to a sample of cognitively intact community-dwelling participants recruited from senior living centers and independent assisted living facilities. These updated SRB prediction equations - being developed from a more medically "clean" sample of cognitively intact older adults who remained stable over 12 months - have the potential to provide a more accurate assessment of reliable change in an individual patient.

The age-related effect on cognitive performance in cognitively healthy elderly is mainly caused by underlying AD pathology or cerebrovascular lesions: implications for cutoffs regarding cognitive impairment

Background

As research in treatments for neurocognitive diseases progresses, there is an increasing need to identify cognitive decline in the earliest stages of disease for initiation of treatment in addition to determining the efficacy of treatment. For early identification, accurate cognitive tests cutoff values for cognitive impairment are essential.

Methods

We conducted a study on 297 cognitively healthy elderly people from the BioFINDER study and created subgroups excluding people with signs of underlying neuropathology, i.e., abnormal cerebrospinal fluid [CSF] β-amyloid or phosphorylated tau, CSF neurofilament light (neurodegeneration), or cerebrovascular pathology. We compared cognitive test results between groups and examined the age effect on cognitive test results.

Results

In our subcohort without any measurable pathology (n = 120), participants achieved better test scores and significantly stricter cutoffs for cognitive impairment for almost all the examined tests. The age effect in this subcohort disappeared for all cognitive tests, apart from some attention/executive tests, predominantly explained by the exclusion of cerebrovascular pathology.

Conclusion

Our study illustrates a new approach to establish normative data that could be useful to identify earlier cognitive changes in preclinical dementias. Future studies need to investigate if there is a genuine effect of healthy aging on cognitive tests or if this age effect is a proxy for higher prevalence of preclinical neurodegenerative diseases.

Suppementary informationl

Supplementary information accompanies this paper at 10.1186/s13195-020-00592-8.

Age-Related Decreases in Interhemispheric Resting-State Functional Connectivity and Their Relationship With Executive Function

Age-related alterations of functional brain networks contribute to cognitive decline. Current theories indicate that age-related intrinsic brain functional reorganization may be a critical marker of cognitive aging. Yet, little is known about how intrinsic interhemispheric functional connectivity changes with age in adults, and how this relates to critical executive functions. To address this, we examined voxel-mirrored homotopic connectivity (VMHC), a metric that quantifies interhemispheric communication, in 93 healthy volunteers (age range: 19-85) with executive function assessment using the Delis-Kaplan Executive Function System (D-KEFS) scales. Resting functional MRI data were analyzed to assess VMHC, and then a multiple linear regression model was employed to evaluate the relationship between age and the whole-brain VMHC. We observed age-related reductions in VMHC of ventromedial prefrontal cortex (vmPFC) and hippocampus in the medial temporal lobe subsystem, dorsal anterior cingulate cortex and insula in salience network, and inferior parietal lobule in frontoparietal control network. Performance on the color-word inhibition task was associated with VMHC of vmPFC and insula, and VMHC of vmPFC mediated the relationship between age and CWIT inhibition reaction times. The percent ratio of correct design scores in design fluency test correlated positively with VMHC of the inferior parietal lobule. The current study suggests that brain interhemispheric functional alterations may be a promising new avenue for understanding age-related cognitive decline.

Plasma amyloid is associated with the rate of cognitive decline in cognitively normal elderly: the SCIENCe project

Plasma biomarkers are promising prognostic tools in individuals with subjective cognitive decline (SCD). We aimed to investigate the relationships of baseline plasma amyloid beta (Aβ)42/Aβ40 and total Tau (tTau) with rate of cognitive decline, in comparison to relationships of baseline cerebrospinal fluid (CSF) Aβ42, tTau, and phosphorylated tau181 (pTau181) with rate of cognitive decline. We included 241 subjects with SCD (age = 61 ± 9, 40% female, Mini-Mental State Examination = 28 ± 2) with follow-up (average: 2 ± 2 years, median visits: 3 [range: 1-11]) for re-evaluation of neuropsychological test performance (attention, memory, language, and executive functioning domains). Using age, gender and education-adjusted linear mixed models, we found that lower plasma Aβ42/Aβ40 was associated with steeper rate of decline on tests for attention, memory, and executive functioning, but not language. Lower CSF Aβ42 was associated with steeper decline on tests covering all domains. Associations for plasma amyloid and cognitive decline mirror those of CSF amyloid. Plasma tTau was not associated with rate of cognitive decline, whereas CSF tTau and pTau181 were on multiple tests covering all domains.

Rates of age- and amyloid β-associated cortical atrophy in older adults with superior memory performance

INTRODUCTION

Superior cognitive performance in older adults may reflect underlying resistance to age-associated neurodegeneration. While elevated amyloid β (Aβ) deposition (Aβ+) has been associated with increased cortical atrophy, it remains unknown whether "SuperAgers" may be protected from Aβ-associated neurodegeneration.

METHODS

Neuropsychologically defined SuperAgers (n = 172) and cognitively normal for age (n = 172) older adults from the Australian Imaging, Biomarkers and Lifestyle study were case matched. Rates of cortical atrophy over 8 years were examined by SuperAger classification and Aβ status.

RESULTS

Of the case-matched SuperAgers and cognitively normal for age older adults, 40.7% and 40.1%, respectively, were Aβ+. Rates of age- and Aβ-associated atrophy did not differ between the groups on any measure. Aβ- individuals displayed the slowest rates of atrophy.

DISCUSSION

Maintenance of superior memory in late life does not reflect resistance to age- or Aβ-associated atrophy. However, those individuals who reached old age without cognitive impairment nor elevated Aβ deposition (i.e. Aβ-) displayed reduced rates of cortical atrophy.

Cognitive Deficits in Older Adults With Psychotic Depression: A Meta-Analysis

A major depressive disorder with psychotic features, that is, psychotic depression (PD), is often accompanied by cognitive deficits, particularly in older patients. We aimed to assess to what extent various cognitive domains are affected in older patients with PD compared to those with nonpsychotic depression (NPD). Therefore, a systematic search was conducted in Medline, Embase, Web of Science, the Cumulative Index to Nursing and Allied Literature (CINAHL), Google Scholar, and Cochrane for all relevant studies. Hereafter, we conducted a meta-analysis of seven studies on cognitive deficits in older adults (55+ years), comparing patients with PD and patients with NPD. Compared to patients with NPD, those with PD not only showed a significantly poorer performance on overall cognitive function, with a Hedges' g effect size of -0.34 (95% confidence interval: -0.56; -0.12; p = 0.003), but also on nearly all separate cognitive domains, with Hedges' g effect sizes ranging from -0.26 to -0.64 (all p's <0.003), of which attention was most adversely affected. Verbal fluency showed no significant effect, although this analysis may have been underpowered. The funnel plot suggested no significant publication bias (Egger test intercept: -2.47; 95% confidence interval: -5.50; 0.55; p = 0.09). We conclude that older patients with PD show more cognitive deficits on all cognitive domains, except for verbal fluency, compared to patients with NPD. It is crucial that clinicians and researchers take cognitive deficits into consideration in older adults with PD.

A longitudinal study of polychlorinated biphenyls and neuropsychological function among older adults from New York State

BACKGROUND

Cross-sectional studies have linked greater polychlorinated biphenyl (PCB) exposure to adverse neuropsychological effects in older adults, including learning, memory, and depressive symptoms. However, no studies among older adults have evaluated the association over time.

OBJECTIVES

To assess the effect of serum PCB levels on neuropsychological function over a 14-year period in a cohort of older men and women from a PCB-contaminated area of New York State.

METHODS

In 2000-2002, we assessed serum PCB levels and neuropsychological function (including the California Verbal Learning Test Trial 1 (CVLTT1) for verbal memory and learning, and the Beck Depression Index (BDI) for depressive symptoms) in 253 men and women, ages 55-74 years. A total of 116 (46%) persons repeated the PCB and neuropsychological assessment 14 years later. To assess the association over time, we used generalized estimating equations with clustering variables time, total PCB (∑PCB), and ∑PCB × time, and adjusted for baseline age, sex, smoking, and total serum-lipids. For statistically significant ∑PCB × time interactions, we evaluated the association between PCBs and either verbal memory and learning or depressive symptoms while holding ∑PCB constant at the 10th and 90th percentiles to clarify the direction of the interaction.

RESULTS

Over the study period, serum ∑PCB levels (wet-weight) declined by 22%, and were associated with different patterns of change over time for memory (∑PCB × Time β = 0.08 p = 0.009) and depressive symptoms (∑PCB × Time β = -0.16 p = 0.013). Specifically, verbal memory and learning decreased (β = -0.08 p = 0.008) and depressive symptoms increased (β = 0.17 p = 0.008) among persons with low exposure (∑PCB levels at the 10th percentile), while persons with high exposure (90th percentile) showed non-significant improvements.

DISCUSSION

In this cohort, declining ∑PCB levels were likely due at least in part to low rates of local fish consumption in recent decades, given the ban since 1976. The decreased verbal memory and learning and increased depressive symptoms over time among persons with low serum ∑PCB levels is consistent with studies of normative aging. However, the small improvements in those outcomes among those with high serum ∑PCB levels was unexpected. Healthy survivor selection bias or uncontrolled confounding may explain this result. It may also indicate that the neurotoxic impacts of PCBs in older adults are not permanent, but future studies are needed to confirm this possibility.

Relationship Between Amyloid-β Positivity and Progression to Mild Cognitive Impairment or Dementia over 8 Years in Cognitively Normal Older Adults

BACKGROUND

Preclinical Alzheimer's disease (AD) is defined by cerebral amyloid-β positivity (Aβ+) in cognitively normal (CN) older adults.

OBJECTIVE

To estimate the risk of progression to the symptomatic stages of AD due to PET Aβ+ and the extent that progression was influenced by other demographic, genetic, and clinical characteristics in a large prospective study.

METHODS

Fine-Gray subdistribution modeling was used to examine the risk of progression from CN to MCI/dementia due to Aβ+, APOEɛ4 carriage, and their interaction in the Australian Imaging, Biomarkers and Lifestyle (AIBL) flagship study of aging CN cohort (n = 599) over 8 years.

RESULTS

17.7% Aβ+ and 8.1% Aβ-progressed over 8 years (OR: 2.43). Risk of progression for Aβ+ was 65-104% greater than Aβ-. Aβ+ APOEɛ4 carriers were at 348% greater risk than all other participants. Significant risk factors of progression in Aβ+ were age (HR: 1.05), PET SUVR (HR: 2.49) and APOE ɛ4 carriage (HR: 2.63); only age was a significant risk factor in Aβ-(HR: 1.09). Aβ-progressors were not near the threshold for Aβ+. These relationships were not moderated by hypertension, diabetes, obesity, or stroke/TIA.

CONCLUSION

Aβ+ is an important prognostic marker for progression from CN to MCI/dementia in older adults and APOEɛ4 carriage provides further predictive value in the presence of Aβ+. These data suggest that Aβ-associated clinical progression is consistent with clinical-pathological models of AD, whereas progression in the absence of elevated Aβ deposition may be the result of neuropathological processes other than AD that accumulate with age.

Robust normative standards for the California Verbal Learning Test (CVLT) ages 60-89: A tool for early detection of memory impairment

Objective: To detect cognitive "impairment," neuropsychologists rely on normative data to compare patient performance to "normal" peers. However, the true normality of normative samples may be called into question given the high prevalence of preclinical proteinopathies amongst clinically normal older adults. Given its common use in memory clinics, we aimed to develop a robust California Verbal Learning Test (CVLT) normative standard reflecting only the most cognitively stable sample of older adults available.Method: Two hundred and twenty-eight older adults (mean age = 69.9, range = 60-89, 91% White, mean education = 17.6 years) who were clinically normal at baseline and demonstrated clinical stability on longitudinal assessment completed the CVLT at baseline. We applied a standardized algorithm to convert raw scores into normalized scaled scores and then regressed on age, sex, and education using fractional polynomial modeling.Results: There were significant main effects of age and sex across CVLT metrics, but not education. Means and standard deviations were higher and less variable in our robust normative data than the data used to create the CVLT-II and CVLT-3 normative standards.Conclusions: These norms set a higher standard for what should be considered "normal" in the spectrum of age-related memory changes and may help clinicians identify patients with memory and potential neurodegenerative changes in the earliest stages, further optimizing clinical management and clinical trial stratification. As with any standard, these robust norms are only appropriately utilized with patients that closely match the demographic profile of the individuals represented in the sample used for this study.

Study of the theory of mind in normal aging: focus on the deception detection and its links with other cognitive functions

Detection of deception is crucial to avoid negative circumstances (financial frauds, social tricks) in daily living. Considering that this cognitive function is especially supported by the prefrontal cortex of the human brain and that these cerebral regions change with advanced age, deception detection may also change with aging. Our purpose is to study this complex ability and its potential links with other cognitive functions, such as the executive control, in normal aging. Thirty-five young adults (YA) aged from 20 to 40, thirty-five old adults (OA) aged from 65 to 79 and thirty very old adults (VOA) aged from 80 to 95 were involved in this study. We propose a novel neuropsychological test (inspired by Theory of Mind Picture Story task) assessing the ability to understand deceptive and cooperative interactions, and tasks involving executive processes (monitoring, task setting, flexibility) to all participants. Between-group analyses show that older participants performed worse than YA on deceptive, cooperative and mixed situations (involving deception and reciprocity) of our task. Significant correlations exist between the deception-cooperation detection and the executive functions. Our results show that these frontal abilities decline after 65 years, even more after 80 years, and they are involved on the deceptive-cooperative situations. The verbal IQ is also linked with the deception-cooperation detection. This suggests that mixed cognitive trainings would allow older adults to detect more easily bad intentions of others, to adjust their behavior to context and to achieve their goals with less risk.

A novel cognitive disease progression model for clinical trials in autosomal-dominant Alzheimer's disease

Clinical trial outcomes for Alzheimer's disease are typically analyzed by using the mixed model for repeated measures (MMRM) or similar models that compare an efficacy scale change from baseline between treatment arms with or without participants' disease stage as a covariate. The MMRM focuses on a single-point fixed follow-up duration regardless of the exposure for each participant. In contrast to these typical models, we have developed a novel semiparametric cognitive disease progression model (DPM) for autosomal dominant Alzheimer's disease based on the Dominantly Inherited Alzheimer Network (DIAN) observational study. This model includes 3 novel features, in which the DPM (1) aligns and compares participants by disease stage, (2) uses a proportional treatment effect similar to the concept of the Cox proportional hazard ratio, and (3) incorporates extended follow-up data from participants with different follow-up durations using all data until last participant visit. We present the DPM model developed by using the DIAN observational study data and demonstrate through simulation that the cognitive DPM used in hypothetical intervention clinical trials produces substantial gains in power compared with the MMRM.

Normative data for the Digit Symbol Substitution Test in a population-based sample aged 65-79 years: Results from the German Health Interview and Examination Survey for Adults (DEGS1)

OBJECTIVE

To provide normative data for the Digit Symbol Substitution Test (DSST) of the Wechsler Adult Intelligence Scale, 3rd edition (WAIS-III) in a population-based sample of community-dwelling older adults in Germany according to age, sex, and level of education.

METHOD

The sample comprised 1385 participants aged 65-79 years from the nationwide representative 'German Health Interview and Examination Survey for Adults' (DEGS1, 2008-2011). Participants with known cognitive impairment or dementia, other medical conditions affecting cognition, or currently using psychotropic drugs were excluded. Educational level was categorized as low, medium, and high according to the Comparative Analyses of Social Mobility in Industrial Nations (CASMIN) scale. Normative values for the DSST according to age, sex, and level of education were estimated by multiple linear regression using population weights.

RESULTS

Mean age was 71.1 years, 48.6% were men and low, medium, and high education levels were 62.8, 24.6, and 12.6%, respectively. Younger age, female sex, and higher level of education were significantly associated with higher DSST scores. Regression-based normative data for the DSST is provided according to age, sex, and level of education. In addition, a normative score calculator is provided.

CONCLUSIONS

These are the first age-, sex-, and education-specific normative data for older individuals for the DSST of the WAIS-III in Germany. These normative data will enable future population-level analyses on impaired cognitive function according to DSST.

Estimates of age-related memory decline are inflated by unrecognized Alzheimer's disease

Cognitive decline is considered an inevitable consequence of aging; however, estimates of cognitive aging may be influenced negatively by undetected preclinical Alzheimer's disease (AD). This study aimed to determine the extent to which estimates of cognitive aging were biased by preclinical AD. Cognitively normal older adults (n = 494) with amyloid-β status determined from positron emission tomography neuroimaging underwent serial neuropsychological assessment at 18-month intervals over 72 months. Estimates of the effects of age on verbal memory, working memory, executive function, and processing speed were derived using linear mixed models. The presence of preclinical AD and clinical progression to mild cognitive impairment or dementia during the study were then added to these models as covariates. Initially, age was associated with decline across all 4 cognitive domains. With the effects of elevated amyloid-β and clinical progression controlled, age was no longer associated with decline in verbal or working memory. However, the magnitude of decline was reduced only slightly for executive function and was unchanged for processing speed. Thus, considered together, the results of the study indicate that undetected preclinical AD negatively biases estimates of age-related cognitive decline for verbal and working memory.

Measuring cognition and function in the preclinical stage of Alzheimer's disease

The Alzheimer's Association's Research Roundtable met in November 2016 to explore how best to measure changes in cognition and function in the preclinical stage of Alzheimer's disease. This review will cover the tools and instruments currently available to identify populations for prevention trials, and measure subtle disease progression in the earliest stages of Alzheimer's disease, and will include discussions of suitable cognitive, behavioral, functional, composite, and biological endpoints for prevention trials. Current prevention trials are reviewed including TOMMOROW, Alzheimer's Prevention Initiative Autosomal Dominant Alzheimer's Disease Trial, the Alzheimer's Prevention Initiative Generation Study, and the Anti-Amyloid Treatment in Asymptomatic Alzheimer's to compare current approaches and tools that are being developed.

Amyloid β-associated cognitive decline in the absence of clinical disease progression and systemic illness

Introduction

High levels of amyloid β (Aβ) are associated with cognitive decline in cognitively normal (CN) older adults. This study investigated the nature of cognitive decline in healthy individuals who did not progress to mild cognitive impairment or dementia.

Method

Cognition was measured over 72 months and compared between low (Aβ−) and high (Aβ+) CN older adults (n = 335) who did not progress to mild cognitive impairment or dementia and who remained free of severe or uncontrolled systemic illness.

Results

Compared to the Aβ− group, the Aβ+ group showed no cognitive impairment at baseline but showed substantial decline in verbal learning, episodic memory, and attention over 72 months.

Discussion

Moderate cognitive decline, particularly for learning and memory, was associated with Aβ+ in CN older adults in the absence of clinical disease progression and uncontrolled or serious comorbid illness.