The Alzheimer’s Disease Neuroimaging Initiative (ADNI) is an ongoing, longitudinal, multicenter study designed to develop clinical, imaging, genetic and biochemical biomarkers for the early detection and tracking of Alzheimer’s disease (AD). The study aimed to enroll 400 subjects with early mild cognitive impairment (MCI), 200 subjects with early AD and 200 normal controls and $67 million funding was provided by both the public and private sectors including the National Institutes on Aging, thirteen pharmaceutical companies and two Foundations that provided support through the Foundation for NIH (FNIH). This article reviews all papers published since the inception of the initiative and summarizes the results as of February, 2011. The major accomplishments of ADNI have been 1) the development of standardized methods for clinical, magnetic resonance imaging (MRI) and positron emission tomography (PET) and cerebrospinal fluid (CSF) biomarkers in a multi-center setting; 2) elucidation of the patterns and rates of change of imaging and CSF biomarker measurements in control, MCI and AD patients. CSF biomarkers are consistent with disease trajectories predicted by β amyloid (Aβ) cascade  and tau mediated neurodegeneration hypotheses for AD while brain atrophy and hypometabolism levels show predicted patterns but exhibit differing rates of change depending on region and disease severity; 3) the assessment of alternative methods of diagnostic categorization. Currently, the best classifiers combine optimum features from multiple modalities including MRI, FDG-PET, CSF biomarkers and clinical tests; 4) the development of methods for the early detection of AD. CSF biomarkers, Aβ42 and tau as well as amyloid PET may reflect the earliest steps in AD pathology in mildly or even non-symptomatic subjects and are leading candidates for the detection of AD in its preclinical stages; 5) the improvement of clinical trial efficiency through the identification of subjects most likely to undergo imminent future clinical decline and the use of more sensitive outcome measures to reduce sample sizes. Baseline cognitive and/or MRI measures generally predicted future decline better than other modalities whereas MRI measures of change were shown to be the most efficient outcome measures; 6) the confirmation of the AD risk loci CLU, CR1 and PICALM and the identification of novel candidate risk loci; 7) worldwide impact through the establishment of ADNI-like programs in Europe, Asia and Australia; 8) understanding the biology and pathobiology of normal aging, MCI and AD through integration of ADNI biomarker data with clinical data from ADNI to stimulate research that will resolve controversies about competing hypotheses on the etiopathogenesis of AD thereby advancing efforts to find disease modifying drugs for AD; and 9) the establishment of infrastructure to allow sharing of all raw and processed data without embargo to interested scientific investigators throughout the world. The ADNI study was extended by a two year Grand Opportunities grant in 2009 and a renewal of ADNI (ADNI2) in October, 2010 through to 2016, with enrollment of an additional 550 participants.
Background: The increased availability of genetic tests for common, complex diseases, such as Alzheimer's disease (AD), raises questions about what people are willing to pay for these services. Methods: We studied willingness-to-pay for genetic testing in a study of AD risk assessment that included APOE genotype disclosure among 276 first-degree relatives of persons with AD. Results: Seventy-one percent reported that they would ask for such testing from their doctor if it were covered by health insurance, and 60% would ask for it even if it required self-pay. Forty-one percent were willing to pay more than $100 for testing, and more than half would have been willing to pay for the test out of pocket. Participants who learned that they were APOE ɛ4 positive and those who had higher education were less likely to want testing if covered by insurance, possibly to avoid discrimination. Conclusion: This is the first report to examine willingness to pay for susceptibility genetic testing in a sample of participants who had actually undergone such testing. These findings reveal that some participants find valuable personal utility in genetic risk information even when such information does not have proven clinical utility.
Susceptibility testing for common, complex adult-onset diseases is projected to become more commonplace as the rapid pace of genomic discoveries continues, and evidence regarding the potential benefits and harms of such testing is needed to inform medical practice and health policy. Apolipoprotein E (APOE) testing for risk of Alzheimer’s disease (AD) provides a paradigm in which to examine the process and impact of disclosing genetic susceptibility for a prevalent, severe and incurable neurological condition. This review summarizes findings from a series of multi-site randomized clinical trials examining psychological and behavioral responses to various methods of genetic risk assessment for AD using APOE disclosure. We discuss challenges involved in disease risk estimation and communication and the extent to which participants comprehend and perceive utility in their genetic risk information. Findings on the psychological impact of test results are presented (e.g., distress), along with data on participants’ health behavior and insurance purchasing responses (e.g., long term care). Finally, we report comparisons of the safety and efficacy of intensive genetic counseling approaches to briefer models that emphasize streamlined processes and educational materials. The implications of these findings for the emerging field of personal genomics are discussed, with directions identified for future research.
Progression of Alzheimer’s dementia (AD) is highly variable. Most estimates derive from convenience samples from dementia clinics or research centers where there is substantial potential for survival bias and other distortions. In a population-based sample of incident AD cases, we examined progression of impairment in cognition, function, and neuropsychiatric symptoms, and the influence of selected variables on these domains.
Longitudinal, prospective cohort study
Cache County (Utah)
328 persons diagnosed with Possible/Probable AD
Mini-Mental State Exam (MMSE), Clinical Dementia Rating sum-of-boxes (CDR-sb), and Neuropsychiatric Inventory (NPI).
Over a mean follow-up of 3.80 (range 0.07–12.90) years, the mean (S.D.) annual rates of change were −1.53 (2.69) on the MMSE, 1.44 (1.82) on the CDR-sb, and 2.55 (5.37) scale points on the NPI. Among surviving participants, 30–58% progressed less than one point/year on these measures, even 5–7 years after dementia onset. Rates of change were correlated between MMSE and CDR-sb (r=−0.62, df=201, p<0.001) and between the CDR-sb and NPI (r=0.20, df=206, p<0.004). Females (LR χ2=8.7, df=2, p=0.013) and those with younger onset (LR χ2=5.7, df=2, p=0.058) declined faster on the MMSE. Although one or more APOE ε4 alleles and ever-use of FDA-approved anti-dementia medications were associated with initial MMSE scores, neither was related to the rate of progression in any domain.
A significant proportion of persons with AD progresses slowly. The results underscore differences between population- vs. clinic-based samples and suggest ongoing need to identify factors that may slow the progression of AD.
Alzheimer’s disease; dementia; cognition; neuropsychiatric symptoms; progression; decline
To evaluate the association of genetic variation with late-onset Alzheimer disease (AD) in African Americans, including genes implicated in recent genome-wide association studies of whites.
We analyzed a genome-wide set of 2.5 million imputed markers to evaluate the genetic basis of AD in an African American population.
Five hundred thirteen well-characterized African American AD cases and 496 cognitively normal African American control subjects.
Data were collected from multiple sites as part of the Multi-Institutional Research on Alzheimer Genetic Epidemiology (MIRAGE) Study and the Henry Ford Health System as part of the Genetic and Environmental Risk Factors for Alzheimer Disease Among African Americans (GenerAAtions) Study.
Several significant single-nucleotide polymorphisms (SNPs) were observed in the region of the apolipoprotein E gene (APOE). After adjusting for the confounding effects of APOE genotype, one of these SNPs, rs6859 in PVRL2, remained significantly associated with AD (P=.0087). Association was also observed with SNPs in CLU, PICALM, BIN1, EPHA1, MS4A, ABCA7, and CD33, although the effect direction for some SNPs and the most significant SNPs differed from findings in data sets consisting of whites. Finally, using the African American genome-wide association study data set as a discovery sample, we obtained suggestive evidence of association with SNPs for several novel candidate genes.
Some genes contribute to AD pathogenesis in both white and African American cohorts, although it is unclear whether the causal variants are the same. A larger African American sample will be needed to confirm novel gene associations, which may be population specific.
Hippocampal sclerosis is a relatively common neuropathological finding (∼10% of individuals over the age of 85 years) characterized by cell loss and gliosis in the hippocampus that is not explained by Alzheimer’s disease. Hippocampal sclerosis pathology can be associated with different underlying causes, and we refer to hippocampal sclerosis in the aged brain as hippocampal sclerosis associated with ageing. Much remains unknown about hippocampal sclerosis associated with ageing. We combined three different large autopsy cohorts: University of Kentucky Alzheimer’s Disease Centre, the Nun Study and the Georgia Centenarian Study to obtain a pool of 1110 patients, all of whom were evaluated neuropathologically at the University of Kentucky. We focused on the subset of cases with neuropathology-confirmed hippocampal sclerosis (n = 106). For individuals aged ≥95 years at death (n = 179 in our sample), each year of life beyond the age of 95 years correlated with increased prevalence of hippocampal sclerosis pathology and decreased prevalence of ‘definite’ Alzheimer’s disease pathology. Aberrant TAR DNA protein 43 immunohistochemistry was seen in 89.9% of hippocampal sclerosis positive patients compared with 9.7% of hippocampal sclerosis negative patients. TAR DNA protein 43 immunohistochemistry can be used to demonstrate that the disease is usually bilateral even when hippocampal sclerosis pathology is not obvious by haematoxylin and eosin stains. TAR DNA protein 43 immunohistochemistry was negative on brain sections from younger individuals (n = 10) after hippocampectomy due to seizures, who had pathologically confirmed hippocampal sclerosis. There was no association between cases with hippocampal sclerosis associated with ageing and apolipoprotein E genotype. Age of death and clinical features of hippocampal sclerosis associated with ageing (with or without aberrant TAR DNA protein 43) were distinct from previously published cases of frontotemporal lobar degeneration TAR DNA protein 43. To help sharpen our ability to discriminate patients with hippocampal sclerosis associated with ageing clinically, the longitudinal cognitive profile of 43 patients with hippocampal sclerosis associated with ageing was compared with the profiles of 75 controls matched for age, gender, education level and apolipoprotein E genotype. These individuals were followed from intake assessment, with 8.2 (average) longitudinal cognitive assessments. A neuropsychological profile with relatively high-verbal fluency but low word list recall distinguished the hippocampal sclerosis associated with ageing group at intake (P < 0.015) and also 5.5–6.5 years before death (P < 0.005). This may provide a first step in clinical differentiation of hippocampal sclerosis associated with ageing versus pure Alzheimer’s disease in their earliest stages. In summary, in the largest series of autopsy-verified patients with hippocampal sclerosis to date, we characterized the clinical and pathological features associated with hippocampal sclerosis associated with ageing.
biomarkers; PGRN; epilepsy; FTLD; cerebrovascular; stroke
In vitro and animal model studies suggest that transthyretin (TTR) inhibits the production of the amyloid β protein, a major contributor to Alzheimer disease (AD) pathogenesis. We evaluated the association of 16 TTR single nucleotide polymorphisms (SNPs) with AD risk in 158 African American and 469 Caucasian discordant sibships from the MIRAGE Study. There was no evidence for association of TTR with AD in either population sample. To examine the possibility that TTR SNPs affect specific components of the AD process, we tested association of these SNPs with four measures of neurodegeneration and cerebrovascular disease defined by magnetic resonance imaging (MRI) in a subset of 48 African American and 265 Caucasian sibships. Five of seven common SNPs and several haplotypes were significantly associated with hippocampal atrophy in the Caucasian sample. Two of these SNPs also showed marginal evidence for association in the African American sample. Results for the other MRI traits were unremarkable. This study highlights the potential value of neuroimaging endophenotypes as a tool for finding genes influencing AD pathogenesis.
This study evaluates the extent to which psychological adaptation (validated measures of depressive symptoms, anxiety, and test-specific distress) after genetic susceptibility testing is influenced by changes in beliefs about Alzheimer's disease (AD) and sharing of test results with others. Adult children of AD patients (N=269) from a randomized clinical trial involving genetic testing for apolipoprotein E (APOE) provided information before, as well as 6 weeks and 12 months after results disclosure. The levels of adaptation varied highly among participants at 12-month assessment. Participants who learned that they were ɛ4 negative (lower risk) had a reduction in perceived risk and concern about developing AD compared with those who learned that they were ɛ4 positive. Those who received results through an extended educational protocol (three in-person visits) had a larger decline in AD concern than those in a condensed protocol (educational brochure and two in-person visits). Increase in AD concern 6 weeks after disclosure was associated with increase in depression scores (b=0.20, P<0.01) and anxiety levels (b=0.20, P<0.01), and higher distress associated with AD genetic testing (b=0.18, P=0.02) 1 year after testing. Increase in perceived risk (b=0.16, P=0.04) was also associated with higher AD genetic testing distress. Sharing the test results with health professionals and friends (but not family) was associated with decrease in depression (b = −0.11, P = 0.05) and anxiety levels (b=−0.16, P<0.01), respectively after a year. Enhancing discussion with regard to risks and concerns about AD during pretesting counseling and obtaining support through sharing the results after testing may help facilitate test recipients' long-term psychological adaptation.
susceptibility genetic testing; AD; APOE; results disclosure; communication; risk perceptions
Background: Direct-to-consumer genetic testing (DTC-GT) provides personalized genetic risk information directly to consumers. Little is known about how and why consumers then communicate the results of this testing to health-care professionals. Aim: To query specialists in clinical genetics about their experience with individuals who consulted them after DTC-GT. Methods: Invitations to participate in a questionnaire were sent to three different groups of genetic professionals, totaling 4047 invitations, asking questions about individuals who consulted them after DTC-GT. For each case reported, respondents were asked to describe how the case was referred to them, the patient's rationale for DTC-GT, and the type of DTC-GT performed. Respondents were also queried about the consequences of the consultations in terms of additional testing ordered. The costs associated with each consultation were estimated. A clinical case series was compiled based upon clinician responses. Results: The invitation resulted in 133 responses describing 22 cases of clinical interactions following DTC-GT. Most consultations (59.1%) were self-referred to genetics professionals, but 31.8% were physician referred. Among respondents, 52.3% deemed the DTC-GT to be “clinically useful.” BRCA1/2 testing was considered clinically useful in 85.7% of cases; 35.7% of other tests were considered clinically useful. Subsequent referrals from genetics professionals to specialists and/or additional diagnostic testing were common, generating individual downstream costs estimated to range from $40 to $20,600. Conclusions: This clinical case series suggests that approximately half of clinical geneticists who saw patients after DTC-GT judged that testing was clinically useful, especially the BRCA1/2 testing. Further studies are needed in larger and more diverse populations to better understand the interactions between DTC-GT and the health-care system.
Biobanks and archived datasets collecting samples and data have become crucial engines of genetic and genomic research. Unresolved, however, is what responsibilities biobanks should shoulder to manage incidental findings (IFs) and individual research results (IRRs) of potential health, reproductive, or personal importance to individual contributors (using “biobank” here to refer to both collections of samples and collections of data). This paper reports recommendations from a 2-year, NIH-funded project. The authors analyze responsibilities to manage return of IFs and IRRs in a biobank research system (primary research or collection sites, the biobank itself, and secondary research sites). They suggest that biobanks shoulder significant responsibility for seeing that the biobank research system addresses the return question explicitly. When re-identification of individual contributors is possible, the biobank should work to enable the biobank research system to discharge four core responsibilities: to (1) clarify the criteria for evaluating findings and roster of returnable findings, (2) analyze a particular finding in relation to this, (3) re-identify the individual contributor, and (4) recontact the contributor to offer the finding. The authors suggest that findings that are analytically valid, reveal an established and substantial risk of a serious health condition, and that are clinically actionable should generally be offered to consenting contributors. The paper specifies 10 concrete recommendations, addressing new biobanks and biobanks already in existence.
incidental findings; return of results; biobanks; research ethics; bioethics; genetics; genomics
Perceptions about the pros and cons of genetic susceptibility testing are among the best predictors of test utilization. How actual testing changes such perceptions has yet to be examined.
In a clinical trial, first-degree relatives of patients with Alzheimer disease received genetic risk assessments for Alzheimer disease including APOE disclosure. Participants rated 11 possible benefits associated with genetic testing (pros) and 10 risks or limitations (cons) before genetic risk disclosure and again 12 months afterward.
Pros were rated higher than cons at baseline (3.53 vs. 1.83, P < 0.001) and at 12 months after risk disclosure (3.33 vs. 1.88, P < 0.001). Ratings of pros decreased during the 12-month period (3.33 vs. 3.53, P < 0.001). Ratings of cons did not change (1.88 vs. 1.83, P = 0.199) except for a three-item discrimination subscale which increased (2.07 vs. 1.92, P = 0.012). Among specific pros and cons, three items related to prevention and treatment changed the most.
The process of APOE genetic risk assessment for Alzheimer disease sensitizes some to its limitations and the risks of discrimination; however, 1-year after disclosure, test recipients still consider the pros to strongly outweigh the cons.
Alzheimer; pros; cons; benefits; discrimination; genetics; risk; APOE; susceptibility testing; education
Vascular factors have been shown to affect the rate of AD progression. However, the effect of the APOE ε4 allele on rate of progression has been ambiguous. Little research to date has examined an interaction between vascular factors and the APOE ε4 allele in predicting decline among AD patients. 216 participants with incident AD from a population of elderly persons in Cache County, Utah, were followed for a mean of 3.3 years and 4.2 follow-up visits. A history of vascular risk factors and conditions and anti-hypertensive use was assessed at the diagnostic visit. Linear mixed effects models tested interactions between the vascular factors, APOE ε4, and time as predictors of clinical progression on the Mini-Mental State Exam (MMSE) and Clinical Dementia Rating-Sum of Boxes (CDR-SB). Multiple comparisons were corrected using the Holm-Bonferroni method. There was a 3-way interaction between stroke, APOE ε4 and time in predicting MMSE decline (LR χ2 = 10.32, 2 df, p = 0.006). For the CDR-SB, there were 3-way interactions between the APOE ε4, time and either myocardial infarction (LR χ2 = 17.83, 2 df, p = 0.0001) or stroke (LR χ2 = 11.48, 2 df, p = 0.003. Results suggest a complex relationship between the APOE ε4 and vascular factors in predicting cognitive and functional progression. Among individuals with a history of stroke or MI at baseline, progression of AD is influenced by APOE ε4 carrier status and varies by time after AD diagnosis.
Alzheimer’s disease; population-based; disease progression; APOE; vascular factors; stroke; myocardial infarction
This study explored the extent to which recipients of genetic susceptibility testing for Alzheimer’s disease (AD) communicated their results to others. It also examined demographic characteristics, along with beliefs about AD, associated with such communication. Participants (N = 271) in a randomized clinical trial involving genetic testing for Apolipoprotein E (APOE) gene variants among first-degree relatives of AD patients reported their communication behaviors 6 weeks after the results disclosure. Information on beliefs about AD and genetic testing was collected at baseline. Eighty-two percent of participants receiving APOE genotype information shared their results with someone. Specifically, 64% shared with family members, 51% with spouse or significant others, 35% with friends, and 12% with health care professionals. Greater AD treatment optimism was associated with communicating results to family (OR=1.43), spouse (OR=1.62), friends (OR =1.81), and health care professionals (OR=2.20). Lower perceived risk (OR=0.98) and higher perceived importance of genetics in the development of AD (OR=1.93) were associated with results communication in general. Lower perceived drawbacks of AD genetic testing was associated with results communication to friends (OR=0.65). Beliefs about AD risks and causes, genetic testing, and development of treatments may partly determine the interpersonal communication patterns of genetic susceptibility test results.
Susceptibility genetic testing; Alzheimer’s disease; APOE communication; disclosure
This study evaluates the extent to which psychological adaptation (validated measures of depressive symptoms, anxiety, and test-specific distress) after genetic susceptibility testing is influenced by changes in beliefs about Alzheimer's disease (AD) and sharing of test results with others. Adult children of AD patients (N=269) from a randomized clinical trial involving genetic testing for apolipoprotein E (APOE) provided information before, as well as 6 weeks and 12 months after results disclosure. The levels of adaptation varied highly among participants at 12-month assessment. Participants who learned that they were ε4 negative (lower risk) had a reduction in perceived risk and concern about developing AD compared with those who learned that they were ε4 positive. Those who received results through an extended educational protocol (three in-person visits) had a larger decline in AD concern than those in a condensed protocol (educational brochure and two in-person visits). Increase in AD concern 6 weeks after disclosure was associated with increase in depression scores (b=0.20, P<0.01) and anxiety levels (b=0.20, P<0.01), and higher distress associated with AD genetic testing (b=0.18, P=0.02) 1 year after testing. Increase in perceived risk (b=0.16, P=0.04) was also associated with higher AD genetic testing distress. Sharing the test results with health professionals and friends (but not family) was associated with decrease in depression (b= −0.11, P=0.05) and anxiety levels (b= −0.16, P<0.01), respectively after a year. Enhancing discussion with regard to risks and concerns about AD during pretesting counseling and obtaining support through sharing the results after testing may help facilitate test recipients' long-term psychological adaptation.
susceptibility genetic testing; AD; APOE; results disclosure; communication; risk perceptions
The authors aim to study subjective ratings of clock drawing test by clinicians and determine interrater reliability and diagnostic accuracy. The clock drawing test has been advocated over the Mini-Mental State Examination as an office screening test for dementia, but use of the clock drawing test by neurologists and dementia specialist clinicians has not been validated. The authors conducted a study of clock drawing test scoring by dementia specialists. The authors randomly assigned 25 clocks from each of six predetermined groups based on consensus diagnosis (cognitive comparison subjects, subjects with a memory complaint but with normal neuropsychological testing, subjects with probable and possible mild cognitive impairment, and subjects with possible and probable Alzheimer’s disease) to dementia specialists for blinded scoring using a binary yes/no impairment system and a 0–10 scale as subjectively determined by each individual clinician rater. The authors collapsed the six groups into three (comparison subjects, mild cognitive impairment patients, and Alzheimer’s disease patients) and analyzed interrater reliability, sensitivity, and specificity for consensus diagnosis of mild cognitive impairment, and Alzheimer’s disease. The authors found excellent interrater reliability, sensitivity, and specificity for predicting consensus diagnosis. The 0–10 clock drawing test rating scale was more predictive of consensus diagnosis than the binary impairment scale. Based on the five clinicians’ average dichotomous rating, the clinicians differentiated comparison and Alzheimer’s disease participants with a sensitivity of 0.75 and a specificity of 0.81. For three of the four comparisons, a cutoff score of two or greater resulted in the maximization of sensitivity and specificity for differentiating diagnostic groups. A cutoff score of four or greater maximized sensitivity (0.54) and specificity (0.74) for differentiating Alzheimer’s disease from mild cognitive impairment. Based on rating systems, clock drawing test scoring by dementia clinicians had excellent interrater reliability and sensitivity for differentiating the mild Alzheimer’s disease subjects from comparison subjects. When utilizing a binary rating scale for the clock drawing test in the absence of clinical information, dementia specialist clinicians at the Boston Medical Center were moderately sensitive and highly specific in separating mild cognitive impairment from healthy comparison subjects. These dementia clinicians were also highly sensitive and less specific in differentiating mild cognitive impairment from Alzheimer’s disease.
Applying Rusbult's investment model of dyadic relationships, we examined the effect of caregiver–care recipient relationship closeness (RC) on cognitive and functional decline in Alzheimer's disease. After diagnosis, 167 participants completed up to six visits, observed over an average of 20 months. Participants were 64% women, had a mean age of 86 years, and mean dementia duration of 4 years. Caregiver-rated closeness was measured using a six-item scale. In mixed models adjusted for dementia severity, dyads with higher levels of closeness (p < .05) and with spouse caregivers (p = .01) had slower cognitive decline. Effect of higher RC on functional decline was greater with spouse caregivers (p = .007). These findings of attenuated Alzheimer's dementia (AD) decline with closer relationships, particularly with spouse caregivers, are consistent with investment theory. Future interventions designed to enhance the caregiving dyadic relationship may help slow decline in AD.
Alzheimer's disease; Caregiving; Interpersonal relations
This paper explores whether and how the behavioral impact of genotype disclosure can be disentangled from the impact of numerical risk estimates generated by genetic tests. Secondary data analyses are presented from a randomized controlled trial of 162 first-degree relatives of Alzheimer’s disease (AD) patients. Each participant received a lifetime risk estimate of AD. Control group estimates were based on age, gender, family history, and assumed ε4-negative apolipoprotein E (APOE) genotype; intervention group estimates were based upon the first three variables plus true APOE genotype, which was also disclosed. AD-specific self-reported behavior change (diet, exercise, and medication use) was assessed at 12 months. Behavior change was significantly more likely with increasing risk estimates, and also more likely, but not significantly so, in ε4-positive intervention group participants (53% changed behavior) than in control group participants (31%). Intervention group participants receiving ε4-negative genotype feedback (24% changed behavior) and control group participants had similar rates of behavior change and risk estimates, the latter allowing assessment of the independent effects of genotype disclosure. However, collinearity between risk estimates and ε4-positive genotypes, which engender high-risk estimates, prevented assessment of the independent effect of the disclosure of an ε4 genotype. Novel study designs are proposed to determine whether genotype disclosure has an impact upon behavior beyond that of numerical risk estimates.
This study evaluates the Alzheimer disease risk perceptions of individuals who accurately recall their genetics-based Alzheimer disease risk assessment.
Two hundred forty-six unaffected first-degree relatives of patients with Alzheimer disease were enrolled in a multisite randomized controlled trial examining the effects of communicating APOE genotype and lifetime Alzheimer disease risk information.
Among the 158 participants who accurately recalled their Alzheimer disease risk assessment 6 weeks after risk disclosure, 75 (47.5%) believed their Alzheimer disease risk was more than 5% points different from the Alzheimer disease risk estimate they were given. Within this subgroup, 69.3% believed that their Alzheimer disease risk was higher than what they were told (discordant high), whereas 30.7% believed that their Alzheimer disease risk was lower (discordant low). Participants with a higher baseline risk perception were more likely to have a discordant-high risk perception (P < 0.05). Participants in the discordant-low group were more likely to be APOE ε4 positive (P < 0.05) and to score higher on an Alzheimer disease controllability scale (P < 0.05).
Our results indicate that even among individuals who accurately recall their Alzheimer disease risk assessment, many people do not take communicated risk estimates at face value. Further exploration of this clinically relevant response to risk information is warranted.
risk recall; risk perception; Alzheimer disease; genetic susceptibility testing
To validate the Neuropsychological Assessment Battery (NAB) List Learning test as a predictor of future multi-domain cognitive decline and conversion to Alzheimer's disease (AD), participants from a longitudinal research registry at a national AD Center were, at baseline, assigned to one of three groups (control, mild cognitive impairment [MCI], or AD), based solely on a diagnostic algorithm for the NAB List Learning test (Gavett et al., 2009), and followed for 1–3 years. Rate of change on common neuropsychological tests and time to convert to a consensus diagnosis of AD were evaluated to test the hypothesis that these outcomes would differ between groups (AD>MCI>control). Hypotheses were tested using linear regression models (n = 251) and Cox proportional hazards models (n = 265). The AD group declined significantly more rapidly than controls on Mini-Mental Status Examination (MMSE), animal fluency, and Digit Symbol; and more rapidly than the MCI group on MMSE and Hooper Visual Organization Test. The MCI group declined more rapidly than controls on animal fluency and CERAD Trial 3. The MCI and AD groups had significantly shorter time to conversion to a consensus diagnosis of AD than controls. The predictive validity of the NAB List Learning algorithm makes it a clinically useful tool for the assessment of older adults.
Memory; Dementia; Differential diagnosis; Aging; Neuropsychology; Neuropsychological tests
Amyloid-β peptide (Aβ42) has been implicated in the pathogenesis of Alzheimer disease (AD). Tarenflurbil, a selective Aβ42-lowering agent, demonstrated encouraging results on cognitive and functional outcomes among mildly affected patients in an earlier phase 2 trial.
To determine the efficacy, safety, and tolerability of tarenflurbil.
Design, Setting, and Patients
A multicenter, randomized, double-blind, placebo-controlled trial enrolling patients with mild AD was conducted at 133 trial sites in the United States between February 21, 2005, and April 30, 2008. Concomitant treatment with cholinesterase inhibitors or memantine was permitted.
Tarenflurbil, 800 mg, or placebo, administered twice a day.
Main Outcome Measures
Co-primary efficacy end points were the change from baseline to month 18 in total score on the subscale of the Alzheimer Disease Assessment Scale–Cognitive Subscale (ADAS-Cog, 80-point version) and Alzheimer Disease Cooperative Studies–activities of daily living (ADCS-ADL) scale. Additional prespecified slope analyses explored the possibility of disease modification.
Of the 1684 participants randomized, 1649 were included in the analysis, and 1046 completed the trial. Tarenflurbil had no beneficial effect on the co-primary outcomes (difference in change from baseline to month 18 vs placebo, based on least squares means: 0.1 for ADAS-Cog; 95% CI, −0.9 to 1.1; P=.86 and −0.5 for ADCS-ADL; 95% CI, −1.9 to 0.9; P=.48) using an intent-to-treat analysis. No significant differences occurred in the secondary outcomes. The ADAS-Cog score decreased by 7.1 points over 18 months. The tarenflurbil group had a small increase in frequency of dizziness, anemia, and infections.
Tarenflurbil did not slow cognitive decline or the loss of activities of daily living in patients with mild AD.
Functional imaging and neuropathological studies suggest that individuals with higher education have better cognitive performance at the same level of brain pathology than less educated subjects. No in vivo studies are available that directly test how education modifies the effect of structural pathology on cognition in Alzheimer’s disease (AD). The present study therefore aimed to measure this effect using data from a large multi-center study. 270 patients with AD underwent cognitive testing using the Mini Mental State Examination (MMSE), apolipoprotein E (APOE) genotyping, and cerebral magnetic resonance imaging. A linear regression analysis was used to examine the relation of medial temporal lobe atrophy (MTA), as a proxy of AD pathology, to MMSE score, adjusting for age, gender, APOE, cerebrovascular disease, ethnicity, education, and disease duration. An interaction term for MTA and education was introduced to test the hypothesis that education modifies the effect of MTA on cognition. There was a significant inverse association between MTA and cognition. Most interestingly, the interaction term between education and MTA was significant suggesting that education modifies the relation of MTA to cognition. At any level of pathology, cognition remained higher for better educated individuals.
Alzheimer’s disease; cognition; cognitive reserve; dementia; education; hippocampus; magnetic resonance imaging; medial temporal lobe atrophy