Screening for memory disorders, dementia and Alzheimer’s disease

Does the presence of chronic pain affect scores on cognitive screening tests/brief cognitive measures for dementia? A systematic review and meta-analysis

OBJECTIVE

Cognitive screening tests can identify potential dementia by indicating a concerning level of cognitive impairment. The older populations for whom this is most relevant are more likely to experience chronic pain, which also impairs cognitive function, but pain's impact on cognitive screening tests specifically remains unknown.

METHOD

We conducted a systematic review and meta-analysis (SR/MA) following PRISMA guidelines evaluating cognitive screening scores in studies involving participants with chronic pain compared with a pain-free control group. Our question was whether the presence of chronic pain (self-reported or based on diagnosis) was associated with poorer performance on these screens, and to identify the heterogeneity across groups and screens.

RESULTS

The 51 studies identified yielded 62 effect size estimates. The pooled g was 0.76 (95% confidence interval 0.57 to 0.95). Heterogeneity was high for the full model (= 93.16%) with some reductions in sub-analyses. Around half of the studies were identified as being at a low risk of bias. There was no evidence of publication bias.

CONCLUSIONS

As a whole, this analysis suggests medium to large effect sizes on cognitive screen performance when people are living with chronic pain. We suggest that clinicians should consider the effect of chronic pain when cognitive screens are employed to investigate dementia. Further research could clarify the effect pain has on different screen sub-domains to aid their effective use with these populations.

A robust harmonization approach for cognitive data from multiple aging and dementia cohorts

INTRODUCTION

Although many cognitive measures have been developed to assess cognitive decline due to Alzheimer's disease (AD), there is little consensus on optimal measures, leading to varied assessments across research cohorts and clinical trials making it difficult to pool cognitive measures across studies.

METHODS

We used a two-stage approach to harmonize cognitive data across cohorts and derive a cross-cohort score of cognitive impairment due to AD. First, we pool and harmonize cognitive data from international cohorts of varying size and ethnic diversity. Next, we derived cognitive composites that leverage maximal data from the harmonized dataset.

RESULTS

We show that our cognitive composites are robust across cohorts and achieve greater or comparable sensitivity to AD-related cognitive decline compared to the Mini-Mental State Examination and Preclinical Alzheimer Cognitive Composite. Finally, we used an independent cohort validating both our harmonization approach and composite measures.

DISCUSSION

Our easy to implement and readily available pipeline offers an approach for researchers to harmonize their cognitive data with large publicly available cohorts, providing a simple way to pool data for the development or validation of findings related to cognitive decline due to AD.

Assessment-related anxiety among older adults: associations with neuropsychological test performance

Anxiety disrupts test performance across academic/testing contexts; however, the impact of anxiety on neuropsychological testing has been examined less frequently among older adults, despite clinical observations of high anxiety and dementia worry among elderly individuals in assessment contexts. The present study examined the impact of trait, state, and test anxiety on measures of processing speed, working memory, verbal memory, and aspects of executive functioning (i.e., set shifting and inhibition). We hypothesized that anxiety specific to neuropsychological assessment would correlate with test performance more consistently than state or trait anxiety. Ninety-three older adults aged 55 to 89 underwent a three-and-a-half-hour comprehensive assessment battery measuring anxiety and neuropsychological test performance. All participants completed the Feelings About Neuropsychological Testing State (FANT-S) and Test (FANT-T) questionnaires, Generalized Anxiety Disorder-seven item (GAD-7), and neuropsychological tests in the domains of processing speed, working memory, verbal memory, and executive functioning. When test scores were regressed on these anxiety measures, increases in test anxiety predicted decreased performance on measures of executive functioning, specifically inhibitory control. State anxiety demonstrated the opposite relationship to performance and predicted increased performance on one measure. Trait anxiety did not predict cognitive assessment performance. Findings were consistent with previous research indicating measures of test anxiety are more sensitive to changes in test performance than measures of trait or state anxiety. Results demonstrated that older adults, even those not referred for a clinical neuropsychological assessment, can show decreased test performance when self-reported anxiety relevant to the neuropsychological assessment context is high.

Differentiation of Subjective Cognitive Decline, Mild Cognitive Impairment, and Dementia Using qEEG/ERP-Based Cognitive Testing and Volumetric MRI in an Outpatient Specialty Memory Clinic

BACKGROUND

Distinguishing between subjective cognitive decline (SCD), mild cognitive impairment (MCI), and dementia in a scalable, accessible way is important to promote earlier detection and intervention.

OBJECTIVE

We investigated diagnostic categorization using an FDA-cleared quantitative electroencephalographic/event-related potential (qEEG/ERP)-based cognitive testing system (eVox® by Evoke Neuroscience) combined with an automated volumetric magnetic resonance imaging (vMRI) tool (Neuroreader® by Brainreader).

METHODS

Patients who self-presented with memory complaints were assigned to a diagnostic category by dementia specialists based on clinical history, neurologic exam, neuropsychological testing, and laboratory results. In addition, qEEG/ERP (n = 161) and quantitative vMRI (n = 111) data were obtained. A multinomial logistic regression model was used to determine significant predictors of cognitive diagnostic category (SCD, MCI, or dementia) using all available qEEG/ERP features and MRI volumes as the independent variables and controlling for demographic variables. Area under the Receiver Operating Characteristic curve (AUC) was used to evaluate the diagnostic accuracy of the prediction models.

RESULTS

The qEEG/ERP measures of Reaction Time, Commission Errors, and P300b Amplitude were significant predictors (AUC = 0.79) of cognitive category. Diagnostic accuracy increased when volumetric MRI measures, specifically left temporal lobe volume, were added to the model (AUC = 0.87).

CONCLUSION

This study demonstrates the potential of a primarily physiological diagnostic model for differentiating SCD, MCI, and dementia using qEEG/ERP-based cognitive testing, especially when combined with volumetric brain MRI. The accessibility of qEEG/ERP and vMRI means that these tools can be used as adjuncts to clinical assessments to help increase the diagnostic certainty of SCD, MCI, and dementia.

Correctness and response time distributions in the MemTrax continuous recognition task: Analysis of strategies and a reverse-exponential model

A critical issue in addressing medical conditions is measurement. Memory measurement is difficult, especially episodic memory, which is disrupted by many conditions. On-line computer testing can precisely measure and assess several memory functions. This study analyzed memory performances from a large group of anonymous, on-line participants using a continuous recognition task (CRT) implemented at https://memtrax.com. These analyses estimated ranges of acceptable performance and average response time (RT). For 344,165 presumed unique individuals completing the CRT a total of 602,272 times, data were stored on a server, including each correct response (HIT), Correct Rejection, and RT to the thousandth of a second. Responses were analyzed, distributions and relationships of these parameters were ascertained, and mean RTs were determined for each participant across the population. From 322,996 valid first tests, analysis of correctness showed that 63% of these tests achieved at least 45 correct (90%), 92% scored at or above 40 correct (80%), and 3% scored 35 correct (70%) or less. The distribution of RTs was skewed with 1% faster than 0.62 s, a median at 0.890 s, and 1% slower than 1.57 s. The RT distribution was best explained by a novel model, the reverse-exponential (RevEx) function. Increased RT speed was most closely associated with increased HIT accuracy. The MemTrax on-line memory test readily provides valid and reliable metrics for assessing individual episodic memory function that could have practical clinical utility for precise assessment of memory dysfunction in many conditions, including improvement or deterioration over time.

Now is the Time to Improve Cognitive Screening and Assessment for Clinical and Research Advancement

Alzheimer’s disease (AD) is the only cause of death ranked in the top ten globally without precise early diagnosis or effective means of prevention or treatment. Further, AD was identified as a pandemic [1] well before COVID-19 was dubbed a 21st century pandemic [2]. And now, with the realization of the prominent secondary impacts of pandemics, there is a growing, widespread recognition of the tremendous magnitude of the impending burden from AD in an aging world population in the coming decades [3]. This appreciation has amplified the growing and pressing need for a new, efficacious, and practical platform to detect and track cognitive decline, beginning in the preliminary (prodromal) phases of the disease, sensitively, accurately, effectively, reliably, efficiently, and remotely [4–7]. Moreover, the parallel necessity of clarifying and understanding risk factors, developing successful prevention strategies [8–17], and discovering and monitoring viable and effective treatments could all benefit from accurate and efficient screening and assessment platforms. Modern recognition of AD [18] as a common affliction of the elderly began in 1968 with a paper by Blessed, Tomlinson, & Roth [19] in which two tests, one a brief assessment of cognitive function and the other a measure of daily function, demonstrated impairment which was associated with the postmortem counts of neurofibrillary tangles, composed mainly of microtubule-associated protein-tau (tau), in the brain, though not to senile plaques, composed mainly of amyloid-β (Aβ). Even in more recent analyses, the tangles correspond with the severity of dementia more than the plaques [20, 21]. Since 1960, a plethora of cognitive tests, paper and pencil [22, 23], simple screening models [24], and computerized [25–27], have been developed to assess the dysfunction associated with AD. However, there has been limited application of Modern Test Theory, which includes Item Characteristic Curve Analysis, used in the technological development of such tools [28–31], along with widespread failure to understand the underlying AD pathological process to guide test development [32, 33]. The lack of such development has likely been a major contributor to the failure of the field to develop timely screening approaches for AD [34, 35], inaccurate assessment of the progression of AD [36], and even now, failure to find an effective approach to stopping AD.

Assessment-related anxiety among older adults: development of a measure

Older adults are the largest population seeking neuropsychological assessment services. Anxiety has been shown to impact test scores, yet no anxiety measure currently exists specific to older adult neuropsychological assessment. This study piloted and validated the Feelings About Neuropsychological Testing measure (FANT), a measure of neuropsychological assessment anxiety developed to measure the cognitive, affective, and physiological aspects of test and state anxiety. The measure was validated on 105 community based older adults aged 55 and older. All participants were administered the FANT, the Generalized Anxiety Disorder- seven item (GAD-7), Test Anxiety Inventory- Short Form (TAI-SF), Patient Health Questionnaire- nine item (PHQ-9), Pittsburgh Sleep Quality Index (PSQI), Dementia Worry Scale (DWS), and PROMIS Cognitive Function Short Form- 6a (CFSF). The measure proved feasible to administer, both the State and Test-specific dimensions demonstrated good internal consistency (state: α =.832; test: α =.894), discriminant validity, and external validity (compared to GAD-7, TAI-SF, PHQ-9, DWS, and CFSF). FANT scores may reveal patients for whom anxiety disrupts attention and attentional control, and therefore has promise as a measure that may inform assessment findings and guide possible intervention to maximize performance during testing sessions and to inform data interpretation.

Validity of the MemTrax Memory Test Compared to the Montreal Cognitive Assessment in the Detection of Mild Cognitive Impairment and Dementia due to Alzheimer's Disease in a Chinese Cohort

BACKGROUND

A valid, reliable, accessible, engaging, and affordable digital cognitive screen instrument for clinical use is in urgent demand.

OBJECTIVE

To assess the clinical utility of the MemTrax memory test for early detection of cognitive impairment in a Chinese cohort.

METHODS

The 2.5-minute MemTrax and the Montreal Cognitive Assessment (MoCA) were performed by 50 clinically diagnosed cognitively normal (CON), 50 mild cognitive impairment due to AD (MCI-AD), and 50 Alzheimer's disease (AD) volunteer participants. The percentage of correct responses (MTx-% C), the mean response time (MTx-RT), and the composite scores (MTx-Cp) of MemTrax and the MoCA scores were comparatively analyzed and receiver operating characteristic (ROC) curves generated.

RESULTS

Multivariate linear regression analyses indicated MTx-% C, MTx-Cp, and the MoCA score were significantly lower in MCI-AD versus CON and in AD versus MCI-AD groups (all with p≤0.001). For the differentiation of MCI-AD from CON, an optimized MTx-% C cutoff of 81% had 72% sensitivity and 84% specificity with an area under the curve (AUC) of 0.839, whereas the MoCA score of 23 had 54% sensitivity and 86% specificity with an AUC of 0.740. For the differentiation of AD from MCI-AD, MTx-Cp of 43.0 had 70% sensitivity and 82% specificity with an AUC of 0.799, whereas the MoCA score of 20 had 84% sensitivity and 62% specificity with an AUC of 0.767.

CONCLUSION

MemTrax can effectively detect both clinically diagnosed MCI and AD with better accuracy as compared to the MoCA based on AUCs in a Chinese cohort.

Episodic-Memory Performance in Machine Learning Modeling for Predicting Cognitive Health Status Classification

BACKGROUND

Memory dysfunction is characteristic of aging and often attributed to Alzheimer's disease (AD). An easily administered tool for preliminary assessment of memory function and early AD detection would be integral in improving patient management.

OBJECTIVE

Our primary aim was to utilize machine learning in determining initial viable models to serve as complementary instruments in demonstrating efficacy of the MemTrax online Continuous Recognition Tasks (M-CRT) test for episodic-memory screening and assessing cognitive impairment.

METHODS

We used an existing dataset subset (n = 18,395) of demographic information, general health screening questions (addressing memory, sleep quality, medications, and medical conditions affecting thinking), and test results from a convenience sample of adults who took the M-CRT test. M-CRT performance and participant features were used as independent attributes: true positive/negative, percent responses/correct, response time, age, sex, and recent alcohol consumption. For predictive modeling, we used demographic information and test scores to predict binary classification of the health-related questions (yes/no) and general health status (healthy/unhealthy), based on the screening questions.

RESULTS

ANOVA revealed significant differences among HealthQScore groups for response time true positive (p = 0.000) and true positive (p = 0.020), but none for true negative (p = 0.0551). Both % responses and % correct had significant differences (p = 0.026 and p = 0.037, respectively). Logistic regression was generally the top-performing learner with moderately robust prediction performance (AUC) for HealthQScore (0.648-0.680) and selected general health questions (0.713-0.769).

CONCLUSION

Our novel application of supervised machine learning and predictive modeling helps to demonstrate and validate cross-sectional utility of MemTrax in assessing early-stage cognitive impairment and general screening for AD.

Putative Survival Advantages in Young Apolipoprotein ɛ4 Carriers are Associated with Increased Neural Stress

Inheritance of a single copy of the apolipoprotein E (APOE) ɛ4 allele increases risk of Alzheimer’s disease (AD) by 3-4-fold, with homozygosity associated with a 12-16-fold increase in risk, relative to ɛ3 allele homozygosity. There is a decreased risk associated with the APOE ɛ2 allele. The pathological consequence of APOE genotype has led to intense efforts to understand the mechanistic basis of the interplay between APOE status and loss of synapses. Numerous ɛ4 allele-related associations have been reported with the potential relevance of these associations to the pathogenesis of AD unknown at this time. In primarily young subjects, we have reviewed a representative body of literature on ɛ4 allele-associations related to the following: cardiovascular responses; impacts on reproduction and fetal development; co-morbidities; resistance to infectious disease; responses to head injury; biochemical differences possibly related to neural stress; and brain structure-function differences. In addition, the literature on the association between the ɛ4 allele and cognitive performance has been reviewed comprehensively. The weight-of-the-evidence supports the hypothesis that possession of the ancestral ɛ4 allele in youth is associated with improved fitness during fetal development, infancy, and youth relative to the more recently appearing ɛ3 allele, at the expense of decreased fitness in old age, which is substantially improved by the ɛ3 allele. However, possession of the ɛ4 allele is also associated with higher levels of synaptic macromolecular turnover, which likely stresses basic cellular neuroplasticity mechanisms. Clinical trials of potential AD therapeutics should consider APOE status as an enrollment criterion.

The Epoch Effect on Cognitive Function Requires Regular Updating of Cognitive Screening Tests

BACKGROUND

Over time, improved cognitive abilities in elderly individuals lead to an overall increase in performance on widely used cognitive screening tests (e.g., Mini-Mental State Examination, MMSE) and impact screening efficacy.

OBJECTIVE

We aimed to examine the epoch effect on cognitive function measured using MMSE, in addition to the influence of demographic characteristics on MMSE. We also evaluated the ability of the MMSE in detecting dementia and examined the discrimination ability and measurement precision of the MMSE.

METHODS

In a cross-sectional survey, Chinese veterans aged ≥60 years were interviewed. Multiple linear regression analysis was applied to explore the factors affecting the MMSE. The expected MMSE score was calculated to examine the epoch effect. The diagnostic accuracy of the MMSE was determined via receiver operating characteristic curve analyses. Item response theory methods were implemented using Stata 16.0.

RESULTS

The MMSE score increased with higher education and decreased with advancing age. The observed MMSE score in this study (26.9) was higher than the expected MMSE score (24.9). It demonstrated 78.3% /84.1% /89.9% sensitivity and 85.8% /79.5% /66.8% specificity in detecting dementia using the cut-off score 25/26/27. The MMSE showed reduced discrimination and provided little information for ability level of -1 and above.

CONCLUSION

Improved cognitive ability over time may increase the performance on cognitive screening tests (e.g., MMSE). This impact of epoch in cognitive function emphasizes the importance of regularly updating cognitive screening tests.

The Dichotomy of Alzheimer's Disease Pathology: Amyloid-β and Tau

In this issue, an article by Tiepolt et al. shows that PET scanning using [¹¹C]PiB can demonstrate both cerebral blood flow (CBF) changes and amyloid-β (Aβ) deposition in patients with mild cognitive dysfunction or mild dementia of Alzheimer’s disease (AD). The CBF changes can be determined because the early scan counts (1–9 minutes) reflect the flow of the radiotracer in the blood passing through the brain, while the Aβ levels are measured by later scan counts (40–70 minutes) after the radiotracer has been cleared from regions to which the radiotracer did not bind. Thus, two different diagnostic measures are obtained with a single injection. Unexpectedly, the mild patients with Aβ positivity had scan data with only a weak relationship to memory, while the relationships to executive function and language function were relatively strong. This divergence of findings from studies of severely impaired patients highlights the importance of determining how AD pathology affects the brain. A possibility suggested in this commentary is that Aβ deposits occur early in AD and specifically in critical areas of the neocortex affected only later by the neurofibrillary pathology indicating a different role of the amyloid-β protein precursor (AβPP) in the development of those neocortical regions, and a separate component of AD pathology may selectively impact functions of these neocortical regions. The effects of adverse AβPP metabolism in the medial temporal and brainstem regions occur later possibly because of different developmental issues, and the later, different pathology is clearly more cognitively and socially devastating.

The MemTrax Test Compared to the Montreal Cognitive Assessment Estimation of Mild Cognitive Impairment

Cognitive impairment is a leading cause of dysfunction in the elderly. When mild cognitive impairment (MCI) occurs in elderly, it is frequently a prodromal condition to dementia. The Montreal Cognitive Assessment (MoCA) is a commonly used tool to screen for MCI. However, this test requires a face-to-face administration and is composed of an assortment of questions whose responses are added together by the rater to provide a score whose precise meaning has been controversial. This study was designed to evaluate the performance of a computerized memory test (MemTrax), which is an adaptation of a continuous recognition task, with respect to the MoCA. Two outcome measures are generated from the MemTrax test: MemTrax_speed and MemTrax_correct. Subjects were administered the MoCA and the MemTrax test. Based on the results of the MoCA, subjects were divided in two groups of cognitive status: normal cognition (n = 45) and MCI (n = 37). Mean MemTrax scores were significantly lower in the MCI than in the normal cognition group. All MemTrax outcome variables were positively associated with the MoCA. Two methods, computing the average MTX score and linear regression were used to estimate the cutoff values of the MemTrax test to detect MCI. These methods showed that for the outcome MemTrax_speed a score below the range of 0.87 – 91 s^-1 is an indication of MCI, and for the outcome MemTrax_correct a score below the range of 85 – 90% is an indication for MCI.

"Choosing Wisely": Apolipoprotein E Genetic Testing for the Diagnosis of Alzheimer's Disease in Dementia Clinics

BACKGROUND

Apolipoprotein E (APOE) ɛ4 allele carriers have an increased risk of late-onset Alzheimer's disease (AD). However, in the "Choosing Wisely" campaign for avoiding unnecessary medical tests, treatments, and procedures, APOE genetic testing is not recommended as a predictive test for AD.

OBJECTIVE

The aim of this study was to investigate the potential value of APOE genetic testing in a specific clinical context.

METHODS

Subjects with poor performance in the Korean version of the Mini-Mental Status Examination for dementia screening (MMSE-DS) with a Z-score of less than -1.5 were recruited from the public health centers. All participants underwent APOE genetic testing. Family history of dementia (FHx) was confirmed if one or more first-degree relatives had dementia.

RESULTS

Among 349 subjects, 162 (46.4%) were diagnosed with AD. APOEɛ4 allele carriers had a much higher risk of AD in the group with FHx than in the group without FHx (OR = 15.81, 95% CI = 2.74-91.21 versus OR = 1.82, 95% CI = 1.00-3.27, z = 2.293, p = 0.011). The sensitivity, specificity, positive predictive value, and negative predictive value for the APOEɛ4 allele were 47.7%, 90.9%, 91.3%, and 46.5% in the group with FHx.

CONCLUSION

It would be a wise choice to perform the APOE genetic testing for the diagnosis of AD in subjects with poor performance in a screening test and a family history of dementia.

Advances in screening instruments for Alzheimer's disease

At its fundamental basis, Alzheimer's disease (AD) is a pathological process that affects neuroplasticity, leading to a specific disruption of episodic memory. This review will provide a rationale for calls to screen for the early detection of AD, appraise the currently available cognitive instruments for AD detection, and focus on the development of the MemTrax test, which provides a new approach to detect the early manifestations and progression of the dementia associated with AD. MemTrax assesses metrics that reflect the effects of neuroplastic processes on learning, memory, and cognition, which are affected by age and AD, particularly episodic memory functions, which cannot presently be measured with enough precision for meaningful use. Further development of MemTrax would be of great value to the early detection of AD and would provide support for the testing of early interventions.

A Computerized Continuous-Recognition Task for Measurement of Episodic Memory

Based on clinical observations of severe episodic memory (EM) impairment in dementia of Alzheimer’s disease (AD), a brief, computerized EM test was developed for AD patient evaluation. A continuous recognition task (CRT) was chosen because of its extensive use in EM research. Initial experience with this computerized CRT (CCRT) showed patients were very engaged in the test, but AD patients had marked failure in recognizing repeated images. Subsequently, the test was administered to audiences, and then a two-minute online version was implemented (http://www.memtrax.com). The online CCRT shows 50 images, 25 unique and 25 repeats, which subjects respectively either try to remember or indicate recognition as quickly as possible. The pictures contain 5 sets of 5 images of scenes or objects (e.g., mountains, clothing, vehicles, etc.). A French company (HAPPYneuron, SAS) provided the test for 2 years, with these results. Of 18,477 individuals, who indicated sex and age 21–99 years and took the test for the first time, 18,007 individuals performed better than chance. In this group, age explained 1.5% of the variance in incorrect responses and 3.5% of recognition time variance, indicating considerable population variability. However, when averaging for specific year of age, age explained 58% of percent incorrect variance and 78% of recognition time variance, showing substantial population variability but a major age effect. There were no apparent sex effects. Further studies are indicated to determine the value of this CCRT as an AD screening test and validity as a measure of EM impairment in other clinical conditions.

In Vitro Models of Brain Disorders

The brain is the most complex organ of the body, and many pathological processes underlying various brain disorders are poorly understood. Limited accessibility hinders observation of such processes in the in vivo brain, and experimental freedom is often insufficient to enable informative manipulations. In vitro preparations (brain slices or cultures of dissociated neurons) offer much better accessibility and reduced complexity and have yielded valuable new insights into various brain disorders. Both types of preparations have their advantages and limitations with regard to lifespan, preservation of in vivo brain structure, composition of cell types, and the link to behavioral outcome is often unclear in in vitro models. While these limitations hamper general usage of in vitro preparations to study, e.g., brain development, in vitro preparations are very useful to study neuronal and synaptic functioning under pathologic conditions. This chapter addresses several brain disorders, focusing on neuronal and synaptic functioning, as well as network aspects. Recent progress in the fields of brain circulation disorders, excitability disorders, and memory disorders will be discussed, as well as limitations of current in vitro models.

Walking While Talking and Risk of Incident Dementia

INTRODUCTION

Walking while talking (WWT) is a performance-based test of divided attention that examines cognitive-motor interactions. The purpose of this study is to examine the predictive validity of WWT for dementia and dementia subtypes.

METHODS

We prospectively studied the associations of WWT performance at baseline with risk of developing incident dementia in 1,156 older adults (mean age: 78.28 ± 5.27 years, 60.7% female) enrolled in the Einstein Aging Study using Cox proportional hazard models. Associations were reported as hazard ratio (HR) with 95% confidence intervals (CI).

RESULTS

Over a median follow-up of 1.90 years (interquartile range: 4.70 years), 85 participants developed incident dementia (53 Alzheimer dementia [AD] and 26 vascular dementia [VaD]). Three gait domains were derived using principal component analysis. Only variability, which loaded heavily for swing time standard deviation (SD) and step time SD, was associated with an increased risk of incident dementia per 1 point increase (HR: 1.24, 95% CI: 1.02-1.54) and VaD (HR: 1.50, 95% CI: 1.06-2.12) after adjusting for demographics, disease burden, mental status, and normal walking velocity. Among eight individual gait variables, only swing time variability SD was associated with increased risk for both incident dementia (HR: 1.35, 95% CI: 1.03-1.77) and VaD (HR: 1.78, 95% CI: 1.12-2.83). Variability and swing time SD were not significantly associated with risk of incident AD.

CONCLUSIONS

Complex walking as assessed by the WWT task is a simple and pragmatic tool for assessing risk of developing dementia, especially VaD, in older adults.

[Validation of the German version of the 6‑item screener : Brief cognitive test with broad application possibilities]

BACKGROUND

Especially during admission the detection of cognitive deficits relevant to everyday life should burden patient and examiner as little as possible. The 6‑item screener (SIS) takes approximately 1 min, is easy to learn, does not require any material and is independent of the patient's visual and fine motor skills. The test was first published in 2002 by Callahan who approved the present German translation.

OBJECTIVE

We checked the convergent and discriminant validity, reliability and sensitivity to change of the German translation among geriatric patients.

MATERIAL AND METHODS

A total of 165 patients in an acute geriatric department performed the SIS (4 times), the mini mental state examination (MMSE, 2 times), clock-drawing test according to Shulman (2 times), the Regensburg verbal fluency test (2 times) and the Montgomery-Åsberg depression rating scale within a period of 16 days. The overall judgment of a physician blinded to the test results served as the reference standard.

RESULTS

The SIS closely correlated with the medical judgment (-0.729). The retest reliability was 0.705 and the internal consistency 0.821 (Cronbach's alpha). The sensitivity to detect cognitive deficits relevant to activities of daily living was 100% if a threshold of 5 points was chosen. The achievement of maximum points largely rules out even mild cognitive impairment.

CONCLUSION

The SIS is a valid, reliable short cognitive test. Using a threshold of 5 points the SIS detects cognitive deficits relevant to daily living with a higher sensitivity than the MMSE with a threshold of 25. When the maximum score is achieved there are no medical indications for further cognitive assessment of clinically unremarkable geriatric patients. The brevity and simple application of the SIS also enable its application outside geriatric wards.

Preoperative Cognitive Performance Dominates Risk for Delirium Among Older Adults

BACKGROUND

Cognitive impairment is a well-recognized risk factor for delirium. Our goal was to determine whether the level of cognitive performance across the nondemented cognitive ability spectrum is correlated with delirium risk and to gauge the importance of cognition relative to other known risk factors for delirium.

METHODS

The Successful Aging after Elective Surgery study enrolled 566 adults aged ≥70 years scheduled for major surgery. Patients were assessed preoperatively and daily during hospitalization for the occurrence of delirium using the Confusion Assessment Method. Cognitive function was assessed preoperatively with an 11-test neuropsychological battery combined into a composite score for general cognitive performance (GCP). We examined the risk for delirium attributable to GCP, as well as demographic factors, vocabulary ability, and informant-rated cognitive decline, and compared the strength of association with risk factors identified in a previously published delirium prediction rule for delirium.

RESULTS

Delirium occurred in 135 (24%) patients. Lower GCP score was strongly and linearly predictive of delirium risk (relative risk = 2.0 per each half standard deviation difference in GCP score, 95% confidence interval, 1.5-2.5). This effect was not attenuated by statistical adjustment for demographics, vocabulary ability, and informant-rated cognitive decline. The effect was stronger than, and largely independent from, both standard delirium risk factors and comorbidity.

CONCLUSION

Risk of delirium is linearly and strongly related to presurgical cognitive performance level even at levels above the population median, which would be considered unimpaired.

Performance-Based Cognitive Screening Instruments: An Extended Analysis of the Time versus Accuracy Trade-off

Early and accurate diagnosis of dementia is key to appropriate treatment and management. Clinical assessment, including the use of cognitive screening instruments, remains integral to the diagnostic process. Many cognitive screening instruments have been described, varying in length and hence administration time, but it is not known whether longer tests offer greater diagnostic accuracy than shorter tests. Data from several pragmatic diagnostic test accuracy studies examining various cognitive screening instruments in a secondary care setting were analysed to correlate measures of test diagnostic accuracy and test duration, building on the findings of a preliminary study. High correlations which were statistically significant were found between one measure of diagnostic accuracy, area under the receiver operating characteristic curve, and surrogate measures of test duration, namely total test score and total number of test items/questions. Longer cognitive screening instruments may offer greater accuracy for the diagnosis of dementia, an observation which has possible implications for the optimal organisation of dedicated cognitive disorders clinics.

Management of cognitive determinants in senile dementia of Alzheimer's type: therapeutic potential of a novel polyherbal drug product

BACKGROUND AND OBJECTIVE

The enigmatic etiology of neurodegenerative diseases poses a challenge for the development of novel and efficient drugs. The objective of the present study was to evaluate the efficacy of a polyherbal (test) formulation on cognitive functions, inflammatory markers and oxidative stress in healthy elderly as well as senile dementia of Alzheimer's type (SDAT) patients.

METHOD

A randomized double-blind placebo- and active-controlled clinical trial was performed in healthy elderly subjects and SDAT patients with an age range of 60-75 years. The polyherbal test formulation along with a placebo was given to healthy elderly subjects while the SDAT patients received either the test formulation containing extracts of Bacopa monnieri (whole plant), Hippophae rhamnoides (leaves and fruits) and Dioscorea bulbifera (bulbils) at a dose of 500 mg or donepezil drug (Aricept) at a dose of 10 mg, twice daily, for a period of 12 months. After every three months, cognitive functions were assessed by determining the mini mental state examination (MMSE) score, digital symbol substitution (DSS; subtest of the Wechsler Adult Intelligence Scale-Revised), immediate and delayed word recall (digital memory apparatus-Medicaid systems, Chandigarh, India), attention span (Attention Span Apparatus-Medicaid systems, Chandigarh, India), functional activity questionnaire (FAQ) and depression (geriatric depression scale) scores. Further inflammatory markers and level of oxidative stress were analyzed using standard biochemical tests.

RESULTS

The trial was performed in 109 healthy subjects and 123 SDAT patients of whom 97 healthy subjects and 104 SDAT patients completed the study. Administration of the test formulation for a period of 12 months was effective in improving cognitive functions in the SDAT patients, when compared to the donepezil-treated group, as determined by the DSS (38.984 ± 3.016 vs 35.852 ± 4.906, P = 0.0001), word recall immediate (3.594 ± 1.003 vs 2.794 ± 0.593, P < 0.0001) and attention span (4.918 ± 1.239 vs 4.396 ± 0.913, P = 0.0208) scores. A significant improvement in the FAQ (11.873 ± 2.751 vs 9.801 ± 1.458, P < 0.0001) and depression (16.387 ± 2.116 vs 21.006 ± 2.778, P < 0.0001) scores was also observed, whereas no significant differences were observed in the MMSE and word recall delayed scores. The level of inflammation and oxidative stress was markedly reduced in the SDAT patients treated with the test formulation when compared to the donepezil-treated group indicating a likely mechanism of action of the test formulation (homocysteine 30.22 ± 3.87 vs 44.73 ± 7.11 nmol/L, P < 0.0001; C-reactive protein [CRP] 4.751 ± 1.149 vs 5.887 ± 1.049 mg/L, P < 0.0001; tumour necrosis factor alpha [TNF-α] 1139.45 ± 198.87 vs 1598.77 ± 298.52 pg/ml, P < 0.0001; superoxide dismutase [SOD] 1145.92 ± 228.75 vs 1296 ± 225.72 U/g Hb, P = 0.0013; glutathione peroxidase [GPx] 20.78 ± 3.14 vs 25.99 ± 4.11 U/g Hb, P < 0.0001; glutathione [GSH] 9.358 ± 2.139 vs 6.831 ± 1.139 U/g Hb, P < 0.0001; thiobarbituric acid reactive substances [TBARS] 131.62 ± 29.68 vs 176.40 ± 68.11 nmol/g Hb, P < 0.0001). Similarly, when healthy elderly subjects treated with the test formulation for 12 months were compared to the placebo group, a significant (P < 0.001) improvement in cognitive measures (MMSE, DSS, word recall delayed but not immediate, attention span, FAQ and depression scores) and a reduction in inflammation (reduction in homocysteine, CRP, IL-6 and TNF-α levels) and oxidative stress levels (reduction in SOD, GPx and TBARS and increase in GSH) was observed. This indicated a protective effect of the test formulation in managing cognitive decline associated with the ageing process.

CONCLUSION

The results of this study demonstrate the therapeutic potential of this novel polyherbal formulation for the management and treatment of SDAT.

Findings from the National Memory Screening Day program

OBJECTIVES

To report experience with a large, nation-wide public memory screening program.

DESIGN

Descriptive study of community-dwelling elderly adults.

SETTING

Local community sites (48 sites agreed to provide data) throughout the United States participating in National Memory Screening Day in November 2010.

PARTICIPANTS

Of 4,369 reported participants, 3,064 had complete data records and are included in this report.

MEASUREMENTS

Participants completed a questionnaire that included basic demographic information and a question about subjective memory concerns. Each site selected one of seven validated cognitive screening tests: Mini-Cog, General Practitioner assessment of Cognition, Memory Impairment Screen, Kokmen Short Test of Mental Status, Mini-Mental State Examination, Montreal Cognitive Assessment, Saint Louis University Mental Status Examination.

RESULTS

Overall, 11.7% failed one of the seven screening tests. As expected, failure rates were higher in older and less-educated participants (P's < .05). Subjective memory concerns were associated with a 40% greater failure rate for persons of similar age and education but no memory concerns (odds ratio = 1.4, 95% confidence interval = 1.07-1.78), although only 11.9% of those who reported memory concerns (75% of all participants) had detectible memory problems.

CONCLUSION

Screening for cognitive impairment in community settings yielded results consistent with expected effects of age and education. The event attracted a large proportion of individuals with memory concerns; 88.1% were told that they did not have memory problems detectible with the tests used. Further studies are needed to assess how participants respond to and use screening information, whether this information ultimately influences decision-making or outcomes, and whether memory screening programs outside healthcare settings have public health value.

Measuring cognition: the Chicago Cognitive Function Measure in the National Social Life, Health and Aging Project, Wave 2

OBJECTIVES

To describe the development of a multidimensional test of cognition for the National Social life, Health and Aging Project (NSHAP), the Chicago Cognitive Function Measure (CCFM).

METHOD

CCFM development included 3 steps: (a) A pilot test of the Montreal Cognitive Assessment (MoCA) to create a standard protocol, choose specific items, reorder items, and improve clarity; (b) integration into a CAPI-based format; and (c) evaluation of the performance of the CCFM in the field. The CCFM was subsequently incorporated into NSHAP, Wave 2 (n = 3,377).

RESULTS

The pre-test (n = 120) mean age was 71.35 (SD 8.40); 53% were female, 69% white, and 70% with college or greater education. The MoCA took an average of 15.6min; the time for the CCFM was 12.0 min. CCFM scores (0-20) can be used as a continuous outcome or to adjust for cognition in a multivariable analysis. CCFM scores were highly correlated with MoCA scores (r = .973). Modeling projects MoCA scores from CCFM scores using the equation: MoCA = (1.14 × CCFM) + 6.83. In Wave 2, the overall weighted mean CCFM score was 13.9 (SE 0.13).

DISCUSSION

A survey-based adaptation of the MoCA was successfully integrated into a nationally representative sample of older adults, NSHAP Wave 2.

Cognitive screening for dementia in primary care: a systematic review

BACKGROUND

Identifying dementia in primary care could minimize the impact of a late intervention; however, it shows high rates of misdiagnosis. One of the reasons seems to be the lack of knowledge of adequate cognitive screening instruments. This is a systematic review of the available instruments for the primary care context.

METHOD

For this systematic review, articles were collected according to the following combined key terms: "cognitive screening" and "dementia" and "primary care" and "review". Studies should be reviews focusing on cognitive screening instruments best used in primary care setting.

RESULTS

Thirteen reviews were selected. In total, it was considered 34 cognitive screening instruments. Half of the instruments can be applied in an adequate time-limit for primary care context. Memory is the most commonly assessed cognitive function (91%). Almost half of the tests are mentioned to have influence of education or cultural factors (44%).

CONCLUSION

Tests such as 6CIT, AMT, GPCOG, Mini-Cog, MIS, MoCA, and STMS seem to be good alternatives to the use of the Mini-Mental State Examination when considering factors such as application time, sensitivity, specificity, and number of studies. However, there is a wide range of tests with different characteristics, therefore it is recommended that the professional gets some expertise in a few number of instruments in order to be able to choose which to use, or use in combination, depending on the setting and the profile of the patient.

The Extension of the German CERAD Neuropsychological Assessment Battery with Tests Assessing Subcortical, Executive and Frontal Functions Improves Accuracy in Dementia Diagnosis

BACKGROUND/AIMS

Alzheimer's disease (AD) is the most common form of dementia. Neuropsychological assessment of individuals with AD primarily focuses on tests of cortical functioning. However, in clinical practice, the underlying pathologies of dementia are unknown, and a focus on cortical functioning may neglect other domains of cognition, including subcortical and executive functioning. The current study aimed to improve the diagnostic discrimination ability of the Consortium to Establish a Registry for Alzheimer's Disease - Neuropsychological Assessment Battery (CERAD-NAB) by adding three tests of executive functioning and mental speed (Trail Making Tests A and B, S-Words).

METHODS

Logistic regression analyses of 594 normal controls (NC), 326 patients with mild AD and 224 patients with other types of dementia (OD) were carried out, and the area under the curve values were compared to those of CERAD-NAB alone.

RESULTS

All comparisons except AD-OD (65.5%) showed excellent classification rates (NC-AD: 92.7%; NC-OD: 89.0%; NC-all patients: 91.0%) and a superior diagnostic accuracy of the extended version.

CONCLUSION

Our findings suggest that these three tests provide a sensible addition to the CERAD-NAB and can improve neuropsychological diagnosis of dementia.

Epidemiology of neurodegenerative diseases in sub-Saharan Africa: a systematic review

BACKGROUND

Sub-Saharan African (SSA) countries are experiencing rapid transitions with increased life expectancy. As a result the burden of age-related conditions such as neurodegenerative diseases might be increasing. We conducted a systematic review of published studies on common neurodegenerative diseases, and HIV-related neurocognitive impairment in SSA, in order to identify research gaps and inform prevention and control solutions.

METHODS

We searched MEDLINE via PubMed, 'Banque de Données de Santé Publique' and the database of the 'Institut d'Epidemiologie Neurologique et de Neurologie Tropicale' from inception to February 2013 for published original studies from SSA on neurodegenerative diseases and HIV-related neurocognitive impairment. Screening and data extraction were conducted by two investigators. Bibliographies and citations of eligible studies were investigated.

RESULTS

In all 144 publications reporting on dementia (n = 49 publications, mainly Alzheimer disease), Parkinsonism (PD, n = 20), HIV-related neurocognitive impairment (n = 47), Huntington disease (HD, n = 19), amyotrophic lateral sclerosis (ALS, n = 15), cerebellar degeneration (n = 4) and Lewy body dementia (n = 1). Of these studies, largely based on prevalent cases from retrospective data on urban populations, half originated from Nigeria and South Africa. The prevalence of dementia (Alzheimer disease) varied between <1% and 10.1% (0.7% and 5.6%) in population-based studies and from <1% to 47.8% in hospital-based studies. Incidence of dementia (Alzheimer disease) ranged from 8.7 to 21.8/1000/year (9.5 to 11.1), and major risk factors were advanced age and female sex. HIV-related neurocognitive impairment's prevalence (all from hospital-based studies) ranged from <1% to 80%. Population-based prevalence of PD and ALS varied from 10 to 235/100,000, and from 5 to 15/100,000 respectively while that for Huntington disease was 3.5/100,000. Equivalent figures for hospital based studies were the following: PD (0.41 to 7.2%), ALS (0.2 to 8.0/1000), and HD (0.2/100,000 to 46.0/100,000).

CONCLUSIONS

The body of literature on neurodegenerative disorders in SSA is large with regard to dementia and HIV-related neurocognitive disorders but limited for other neurodegenerative disorders. Shortcomings include few population-based studies, heterogeneous diagnostic criteria and uneven representation of countries on the continent. There are important knowledge gaps that need urgent action, in order to prepare the sub-continent for the anticipated local surge in neurodegenerative diseases.

Clinical evaluation of early cognitive symptoms

The etiology of cognitive impairment in older adults is almost always a clinical diagnosis without definitive biomarkers. The clinical evaluation, therefore, is indispensable. Evaluating cognitive symptoms requires a deliberate approach to define the onset, course, and nature of symptoms. An informant who knows the patient well is essential. The physician must have a working knowledge of the basics of cognitive function. The neurologic examination also is fundamental to defining the origin of cognitive impairment. Extraocular movements, speech, and gait are examples of high-yield examination findings that can be observed and tested quickly, adding to the clinical impression.

The sensitivity and specificity of subjective memory complaints and the subjective memory rating scale, deterioration cognitive observee, mini-mental state examination, six-item screener and clock drawing test in dementia screening

BACKGROUND

The effectiveness of dementia screening depends on the availability of suitable screening tools with good sensitivity and specificity to confidently distinguish normal age-related cognitive decline from dementia. The aim of this study was to evaluate the discriminant validity of 7 screening measures for dementia.

METHODS

A sample of 140 participants aged ≥60 years living in a residential facility for the aged were assessed clinically and assigned caseness for dementia using the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revised diagnostic criteria. Sensitivity and specificity of a selection of the following screening measures were tested using receiver operating characteristic (ROC) analysis for individual and combined tests: the Mini-Mental State Examination (MMSE), Six-Item Screener (SIS), Subjective Memory Complaint, Subjective Memory Complaint Clinical (SMCC), Subjective Memory Rating Scale (SMRS), Deterioration Cognitive Observee (DECO) and the Clock Drawing Test (CDT).

RESULTS

Using ROC analyses, the SMCC, MMSE and CDT were found to be 'moderately accurate' in screening for dementia with an area under the curve (AUC) >0.70. The AUCs for the SIS (0.526), SMRS (0.661) and DECO (0.687) classified these measures as being 'less accurate'. At recommended cutoff scores, the SMCC had a sensitivity of 90.9% and specificity of 45.7%; the MMSE had a sensitivity of 63.6% and a specificity of 76.0%, and the CDT had a sensitivity of 44.4% and a specificity of 88.9%. Combining the SMCC and MMSE did not improve their predictive power except for a modest increase when using the sequential rule.

CONCLUSION

The SMCC is composed of valid screening questions that have high sensitivity, are simple to administer and ideal for administration at the community or primary health care level as a first level of 'rule-out' screening. The MMSE can be included at a second stage of screening at the general hospital level and the CDT in specialist clinical settings. Sequential use of the SMCC and MMSE will improve the specificity of the former and the sensitivity of the latter.

Should the mini-mental state examination be retired?

INTRODUCTION

Short cognitive tests are routinely used in clinical practice to detect and screen for cognitive impairment and dementia. These cognitive tests should meet minimum criteria for both applicability and psychometric qualities.

DEVELOPMENT

The Mini-Mental State Examination (MMSE) is the most frequently applied short cognitive test, and the article introducing it remains a milestone in the history of medicine. Its main advantages are its widespread use and the extensive empirical evidence that supports it. However, the MMSE has important shortcomings, including lack of standardisation, its lack of suitability for illiterate subjects, the considerable effect of socio-educational variables on results, and its limited effectiveness for detecting cognitive impairment. Lastly, since the test is copyright-protected, using it is necessarily either costly or fraudulent. Newer available instruments do not share these shortcomings and have demonstrated greater diagnostic accuracy for detecting cognitive impairment and dementia, as well as being more cost-effective than the MMSE CONCLUSION: It is time to acknowledge the MMSE's important role in the history of medicine and grant it a deserved and honourable retirement. Its place will be taken by more effective instruments that require less time, are user-friendly and free of charge, can be applied to all individuals, and yield more equitable outcomes.

Screening for Alzheimer’s Disease

Screening rates for Alzheimer’s disease (AD) and memory impairment are low. There is misinformation, fear, and stigma associated with memory loss and aging. Physicians are slow or reluctant to screen for memory impairment in older adults. The challenges to effective screening for AD are not unique. Thirty years ago, screening for breast cancer also suffered from low participation, fear, stigma, and misinformation. Targeted public health strategies increased disease awareness and early detection for breast cancer, and today, breast cancer screening is generally accepted by health care providers and the public. Strategies used to increase breast cancer screening can serve as examples for the promotion of screening and early detection for AD.

Cognitive approaches to early Alzheimer's disease diagnosis

In this article, cognitive measures in the screening of individuals at risk for Alzheimer disease (AD) are reviewed. Use of cognitive tasks in identifying clinical cases of AD is considered, as well as methods for detecting those in the prodromal stages of the disease, including cognitive screening instruments. Traditional assessments, such as the mini-mental state examination, as well as contemporary computerized screening instruments, are examined. Areas of cognition for investigation in the detection of prodromal AD are recommended. The prospects for general cognitive screening are reviewed, and more engaging technologies to tests individuals at risk for developing AD are recommended.

A Critical Review of the Use of Telephone Tests to Identify Cognitive Impairment in Epidemiology and Clinical Research

We reviewed the use of telephone tests to identify cognitive impairment. We searched PubMed for epidemiological studies and clinical trials reporting the use of telephone tests to identify cognitive impairment. Validation studies and papers published more than 10 years ago were excluded. A total of 132 abstracts were identified, from which 19 epidemiological studies and four clinical trials were selected. Telephone tests were found to reduce selection bias in epidemiology by including people over large areas and facilitating follow-up in longitudinal studies. The most widely used tests were the Telephone Interview for Cognitive Status (TICS) and its modified version, the TICSm. Interviewing a proxy was included in most of the studies to compensate for the unavailability of some participants because of deafness, disease or death. In the epidemiological studies, results of telephone tests were seldom confirmed by a medical examination. Telephone screening for cognitive impairment to identify individuals eligible for clinical trials is impeded by low efficiency and lack of sensitivity for separating early pathological cognitive impairment from dementia and normal ageing.

Improving dementia care: the role of screening and detection of cognitive impairment

The value of screening for cognitive impairment, including dementia and Alzheimer's disease, has been debated for decades. Recent research on causes of and treatments for cognitive impairment has converged to challenge previous thinking about screening for cognitive impairment. Consequently, changes have occurred in health care policies and priorities, including the establishment of the annual wellness visit, which requires detection of any cognitive impairment for Medicare enrollees. In response to these changes, the Alzheimer's Foundation of America and the Alzheimer's Drug Discovery Foundation convened a workgroup to review evidence for screening implementation and to evaluate the implications of routine dementia detection for health care redesign. The primary domains reviewed were consideration of the benefits, harms, and impact of cognitive screening on health care quality. In conference, the workgroup developed 10 recommendations for realizing the national policy goals of early detection as the first step in improving clinical care and ensuring proactive, patient-centered management of dementia.

CERAD-neuropsychological battery in screening mild Alzheimer's disease

OBJECTIVES

The Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery (nb) is used as an evaluation tool for dementia. In Finland, CERAD-nb was introduced in 1999 and has been proposed to be used in primary health care. However, some of its parts need reassessment and focusing. The goal of this study was to examine the sensitivity and specificity of the subtests and their cut-off points most appropriate for identifying mild Alzheimer's disease (AD).

MATERIALS AND METHODS

The study population consisted of 171 patients with mild AD and 315 cognitively normal elderly. Both groups underwent CERAD-nb investigation as a part of a wider examination procedure.

RESULTS

The most efficient subtests to discriminate patients with mild AD from the normal elderly were Wordlist delayed recall and savings, Wordlist learning and Wordlist recognition and a new variable of Total recall. Optimal cut-off points for each subtest are suggested. The sensitivities of the verbal memory subtests varied between 0.75 and 0.94, the specificities between 0.80 and 0.93 and the areas under the receiver operating characteristics curve between 0.89 and 0.96.

CONCLUSIONS

The CERAD-nb is capable of differentiating cases with mild AD from normal elderly individuals particularly with its verbal memory subtests. New cut-off scores for CERAD's subtests validated in the study further enhance the differentiating power, and with these clarifications, CERAD-nb is considered appropriate to be used as a screening tool for AD even in primary health care.

Estimating and disclosing the risk of developing Alzheimer's disease: challenges, controversies and future directions

With Alzheimer's disease increasing in prevalence and public awareness, more people are becoming interested in learning their chances of developing this condition. Disclosing Alzheimer's disease risk has been discouraged because of the limited predictive value of available tests, lack of prevention and treatment options, and concerns regarding potential psychological and social harms. However, challenges to this status quo include the availability of direct-to-consumer health risk information (e.g., genetic susceptibility tests), as well as a growing literature suggesting that people seeking risk information for Alzheimer's disease through formal education and counseling protocols generally find it useful and do not experience adverse effects. This paper reviews current and potential methods of risk assessment for Alzheimer's disease, discusses the process and impact of disclosing risk to interested patients and consumers, and considers the practical and ethical challenges in this emerging area. Anticipated future directions are addressed.

Memory loss in Alzheimer's disease: implications for development of therapeutics

Alzheimer's disease (AD) is a progressive neurodegenerative disease marked by a constellation of cognitive disturbances, the earliest and most prominent being impaired episodic memory. Episodic memory refers to the memory system that allows an individual to consciously retrieve a previously experienced item or episode of life. Many recent studies have focused on characterizing how AD pathology impacts particular aspects of episodic memory and underlying mental and neural processes. This review summarizes the findings of those studies and discusses the effects of current and promising treatments for AD on episodic memory. The goal of this review is to raise awareness of the strides that cognitive neuroscientists have made in understanding intact and dysfunctional memory. Knowledge of the specific memorial processes that are impaired in AD may be of great value to basic scientists developing novel therapies and to clinical researchers assessing the efficacy of those therapies.