[show abstract][hide abstract] ABSTRACT: Neuropathologic heterogeneity is often present among Alzheimer disease (AD) patients. We sought to determine whether amyloid imaging measures of AD are affected by concurrent pathologies. Thirty-eight clinically and pathologically defined AD and 17 nondemented patients with quantitative florbetapir F-18 (F-AV-45) positron emission tomography (PET) imaging during life and postmortem histological β-amyloid quantification and neuropathologic examination were assessed. AD patients were divided on the basis of concurrent pathologies, including those with Lewy bodies (LBs) (n = 21), white matter rarefaction (n = 27), severe cerebral amyloid angiopathy (n = 11), argyrophilic grains (n = 5), and TAR DNA binding protein-43 inclusions (n = 18). Many patients exhibited more than 1 type of concurrent pathology. The ratio of cortical to cerebellar amyloid imaging signal (SUVr) and immunohistochemical β-amyloid load were analyzed in 6 cortical regions of interest. All AD subgroups had strong and significant correlations between SUVr and histological β-amyloid measures (p < 0.001). All AD subgroups had significantly greater amyloid measures versus nondemented patients, and mean amyloid measures did not significantly differ between AD subgroups. When comparing AD cases with and without each pathology, AD cases with LBs had significantly lower SUVr measures versus AD cases without LBs (p = 0.002); there were no other paired comparison differences. These findings indicate that florbetapir-PET imaging is not confounded by neuropathological heterogeneity within AD.
Journal of neuropathology and experimental neurology. 12/2013;
[show abstract][hide abstract] ABSTRACT: Treatment strategies for patients with depression and cognitive impairment (DEP-CI), who are at high risk to develop a clinical diagnosis of dementia, are not established. This issue is addressed in the donepezil treatment of cognitive impairment and depression (DOTCODE) pilot clinical trial. The DOTCODE study is the first long-term treatment trial that assesses differences in conversion to dementia and cognitive change in DEP-CI patients using a study design of open antidepressant medication plus add-on randomized, double-blind, placebo-controlled treatment with the acetylcholinesterase inhibitor donepezil. In Phase 1, DEP-CI patients receive optimized antidepressant treatment for 16weeks. In Phase 2, antidepressant treatment is continued with the addition of randomized, double-blind treatment with donepezil or placebo. The total study duration for each patient is 78weeks (18months). Eighty DEP-CI outpatients (age 55 to 95years) are recruited: 40 at New York State Psychiatric Institute/Columbia University and 40 at Duke University Medical Center. The primary outcome is conversion to a clinical diagnosis of dementia. The secondary outcomes are cognitive change scores in Selective Reminding Test (SRT) total recall and the modified Alzheimer's Disease Assessment Scale (ADAS-cog). Other key assessments include the 24-item Hamilton Depression Rating Scale and antidepressant response; Clinical Global Impression (CGI) for depression, cognition, and global status; neuropsychological test battery for diagnosis; informant report of functional abilities (Pfeffer FAQ); Treatment Emergent Symptom Scale (TESS) for somatic side effects. Apolipoprotein E ε4 status, odor identification deficits, and MRI entorhinal/hippocampal cortex atrophy at baseline are evaluated as neurobiological moderators of donepezil treatment effects.
[show abstract][hide abstract] ABSTRACT: Case reports suggest a relationship between cholinesterase inhibitors (ChEIs) and Pisa syndrome (PS), also known as pleurothotonus, a form of dystonia, but this relationship has not been systematically examined. Our objective was to estimate the adjusted reporting ratios of PS with donepezil, rivastigmine, and galantamine in the United States Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) database.
Retrospective analysis of adverse event reports in the FAERS database.
Patients with drug-related adverse events in the FAERS database.
The Gamma Poisson Shrinker algorithm was used to estimate the empirical Bayes geometric mean (EBGM) along with the lower and upper 90% confidence interval (CI) limits (EB05 and EB95, respectively), as measures of the adjusted reporting ratio of PS in patients taking ChEIs. EB05 > 2.0 was used as the cutoff for significance for the signals. The EBGM (EB05) was 37.9 (30) for all ChEIs, 25.6 (17.6) for donepezil, 76.4 (50.3) for galantamine, and 33.7 (21.2) for rivastigmine. All adverse event signals were strongly significant based on the a priori set EB05 cutoff. The female:male ratio in the reported cases was 2:1. No significant signals were found between ChEIs and other dystonias. About half of the ChEI users were also taking concomitant antipsychotics.
Although FAERS data cannot establish causality due to reporting biases, our findings support a potential dopaminergic-cholinergic imbalance as an underlying mechanism for PS and may help increase clinician awareness, early identification, and treatment of ChEI-related dystonias.
[show abstract][hide abstract] ABSTRACT: All antipsychotic medications carry warnings of increased mortality for older adults, but little is known about comparative mortality risks between individual agents.
To estimate the comparative mortality risks of commonly prescribed antipsychotic agents in older people living in the community.
A retrospective, claims-based cohort study was conducted of people over 65 years old living in the community who had been newly prescribed risperidone, olanzapine, quetiapine, haloperidol, aripiprazole or ziprasidone (n = 136 393). Propensity score-adjusted Cox proportional hazards models assessed the 180-day mortality risk of each antipsychotic compared with risperidone.
Risperidone, olanzapine and haloperidol showed a dose-response relation in mortality risk. After controlling for propensity score and dose, mortality risk was found to be increased for haloperidol (hazard ratio (HR) = 1.18, 95% CI 1.06-1.33) and decreased for quetiapine (HR = 0.81, 95% CI 0.73-0.89) and olanzapine (HR = 0.82, 95% CI 0.74-0.90).
Significant variation in mortality risk across commonly prescribed antipsychotics suggests that antipsychotic selection and dosing may affect survival of older people living in the community.
The British journal of psychiatry: the journal of mental science 08/2013; · 6.62 Impact Factor
[show abstract][hide abstract] ABSTRACT: Background
A critical and as-yet unmet need in Alzheimer disease (AD) research is the development of novel markers that can identify individuals at risk for cognitive decline due to AD. This would aid intervention trials designed to slow the progression of AD by increasing diagnostic certainty, and provide new pathophysiologic clues and potential drug targets.
We used two metabolomics platforms (gas chromatography-time of flight mass spectrometry [GC-TOF] and liquid chromatography LC-ECA array [LC-ECA]) to measure a number of metabolites in cerebrospinal fluid (CSF) from patients with AD dementia and from cognitively normal controls. We used stepwise logistic regression models with cross-validation to assess the ability of metabolite markers to discriminate between clinically diagnosed AD participants and cognitively normal controls and we compared these data with traditional CSF Luminex immunoassay amyloid-β and tau biomarkers. Aβ and tau biomarkers had high accuracy to discriminate cases and controls (testing area under the curve: 0.92). The accuracy of GC-TOF metabolites and LC-ECA metabolites by themselves to discriminate clinical AD participants from controls was high (testing area under the curve: 0.70 and 0.96, respectively).
Our study identified several CSF small-molecule metabolites that discriminated especially well between clinically diagnosed AD and control groups. They appear to be suitable for further confirmatory and validation studies, and show the potential to provide predictive performance for AD.
[show abstract][hide abstract] ABSTRACT: OBJECTIVE: To compare differences in gray matter volumes, white matter and subcortical gray matter hyperintensities, neuropsychological factors, and treatment outcome between early- and late-onset late-life depressed (LLD) subjects. METHODS: We conducted a prospective, nonrandomized, controlled trial at the outpatient clinics at Washington University and Duke University on 126 subjects, aged 60 years or older, who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for major depression, scored 20 or more on the Montgomery-Asberg Depression Rating Scale (MADRS), and received neuropsychological testing and magnetic resonance imaging. Subjects were excluded for cognitive impairment or severe medical disorders. After 12 weeks of sertraline treatment, subjects' MADRS scores over time and neuropsychological factors were studied. RESULTS: Left anterior cingulate thickness was significantly smaller in the late-onset depressed group than in the early-onset LLD subjects. The late-onset group also had more hyperintensities than the early-onset LLD subjects. No differences were found in neuropsychological factor scores or treatment outcome between early-onset and late-onset LLD subjects. CONCLUSION: Age at onset of depressive symptoms in LLD subjects are associated with differences in cortical thickness and white matter and subcortical gray matter hyperintensities, but age at onset did not affect neuropsychological factors or treatment outcome.
The American journal of geriatric psychiatry: official journal of the American Association for Geriatric Psychiatry 06/2013; · 3.35 Impact Factor
[show abstract][hide abstract] ABSTRACT: (18)F-florbetapir positron emission tomography (PET) imaging of the brain is now approved by the Food and Drug Administration (FDA) approved for estimation of β-amyloid neuritic plaque density when evaluating patients with cognitive impairment. However, its impact on clinical decision-making is not known. We present 11 cases (age range 67-84) of cognitively impaired subjects in whom clinician surveys were done before and after PET scanning to document the theoretical impact of amyloid imaging on the diagnosis and treatment plan of cognitively impaired subjects. Subjects have been clinically followed for about 5 months after the PET scan. Negative scans occurred in five cases, leading to a change in diagnosis for four patients and a change in treatment plan for two of these cases. Positive scans occurred in six cases, leading to a change in diagnosis for four patients and a change in treatment plan for three of these cases. Following the scan, only one case had indeterminate diagnosis. Our series suggests that both positive and negative florbetapir PET scans may enhance diagnostic certainty and impact clinical decision-making. Controlled longitudinal studies are needed to confirm our data and determine best practices.
[show abstract][hide abstract] ABSTRACT: Connectomics, the comprehensive mapping of all neural connections in the brain, is an emerging field with great promise.(1-6) Connectomics has its origin in graph theory, a branch of mathematics developed in the 18th century by the Swiss mathematical genius Leonhard Euler to solve the problem known as the Seven Bridges of Königsberg.(4-6) Königsberg, Prussia, was a city on the Pregel River with 2 islands linked to each other and the mainland by 7 bridges.(4) The challenge, to find a continuous path that crosses each bridge exactly once and returns to the starting point,(4) was solved by Euler, who determined, using graph theory, that it was mathematically impossible. In more recent times, scientists have used graph theory to probe the weaknesses of the New York City electrical power grid, the social network of the Screen Actors Guild, and the spread of happiness in the Framingham study cohort.(4-6) The successful reconstruction of all neural and synaptic connections in Caenorhabditis elegans, followed by partial reconstructions of a mouse visual cortex, has naturally led to great interest in the human brain connectome.(1,5.)
[show abstract][hide abstract] ABSTRACT: Alzheimer's disease is a progressive neurodegenerative disorder that causes severe cognitive decline, functional disability, and eventually death. Although there is no cure for this illness, early diagnosis and treatment can reduce or delay cognitive and functional decline, allow patients to avoid medications that worsen cognition, and give patients a greater opportunity to actively participate in their treatment and plan for the future. In this Webcast, experts discuss the presentation and course of Alzheimer's disease, an evidence-based screening tool that can aid in identifying early signs of cognitive impairment in at-risk patients, and imaging and other biomarker measurement tools that can be used to differentiate between diagnoses or to measure disease progress.
The Journal of Clinical Psychiatry 03/2013; 74(3):e06. · 5.81 Impact Factor
[show abstract][hide abstract] ABSTRACT: OBJECTIVE: To evaluate the performance characteristics of florbetapir F18 positron emission tomography (PET) in patients with Alzheimer's disease (AD), mild cognitive impairment (MCI), and healthy control subjects (HCs). METHODS: Florbetapir PET was acquired in 184 subjects (45 AD patients, 60 MCI patients, and 79 HCs) within a multicenter phase 2 study. Amyloid burden was assessed visually and quantitatively, and was classified as positive or negative. RESULTS: Florbetapir PET was rated visually amyloid positive in 76% of AD patients, 38% of MCI patients, and 14% of HCs. Eighty-four percent of AD patients, 45% of MCI patients, and 23% of HCs were classified as amyloid positive using a quantitative threshold. Amyloid positivity and mean cortical amyloid burden were associated with age and apolipoprotein E ε4 carrier status. CONCLUSIONS:: The data are consistent with expected rates of amyloid positivity among individuals with clinical diagnoses of AD and MCI, and indicate the potential value of florbetapir F18 PET as an adjunct to clinical diagnosis.
Alzheimer's & dementia: the journal of the Alzheimer's Association 01/2013; · 14.48 Impact Factor
[show abstract][hide abstract] ABSTRACT: To investigate whether there is a specific dose-dependent effect of the Apolipoprotein E (APOE) ε4 and ε2 alleles on hippocampal volume, across the cognitive spectrum, from normal aging to Alzheimer's Disease (AD).
We analyzed MR and genetic data on 662 patients from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database-198 cognitively normal controls (CN), 321 mild-cognitive impairment (MCI) subjects, and 143 AD subjects-looking for dose-dependent effects of the ε4 and ε2 alleles on hippocampal volumes. Volumes were measured using a fully-automated algorithm applied to high resolution T1-weighted MR images. Statistical analysis consisted of a multivariate regression with repeated-measures model.
There was a dose-dependent effect of the ε4 allele on hippocampal volume in AD (p = 0.04) and MCI (p = 0.02)-in both cases, each allele accounted for loss of >150 mm(3) (approximately 4%) of hippocampal volume below the mean volume for AD and MCI subjects with no such alleles (Cohen's d = -0.16 and -0.19 for AD and MCI, respectively). There was also a dose-dependent, main effect of the ε2 allele (p<0.0001), suggestive of a moderate protective effect on hippocampal volume-an approximately 20% per allele volume increase as compared to CN with no ε2 alleles (Cohen's d = 0.23).
Though no effect of ε4 was seen in CN subjects, our findings confirm and extend prior data on the opposing effects of the APOE ε4 and ε2 alleles on hippocampal morphology across the spectrum of cognitive aging.
PLoS ONE 01/2013; 8(2):e54483. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: The pathogenic mechanisms of Alzheimer's disease (AD) remain largely unknown and clinical trials have not demonstrated significant benefit. Biochemical characterization of AD and its prodromal phase may provide new diagnostic and therapeutic insights. We used targeted metabolomics platform to profile cerebrospinal fluid (CSF) from AD (n=40), mild cognitive impairment (MCI, n=36) and control (n=38) subjects; univariate and multivariate analyses to define between-group differences; and partial least square-discriminant analysis models to classify diagnostic groups using CSF metabolomic profiles. A partial correlation network was built to link metabolic markers, protein markers and disease severity. AD subjects had elevated methionine (MET), 5-hydroxyindoleacetic acid (5-HIAA), vanillylmandelic acid, xanthosine and glutathione versus controls. MCI subjects had elevated 5-HIAA, MET, hypoxanthine and other metabolites versus controls. Metabolite ratios revealed changes within tryptophan, MET and purine pathways. Initial pathway analyses identified steps in several pathways that appear altered in AD and MCI. A partial correlation network showed total tau most directly related to norepinephrine and purine pathways; amyloid-beta (Ab42) was related directly to an unidentified metabolite and indirectly to 5-HIAA and MET. These findings indicate that MCI and AD are associated with an overlapping pattern of perturbations in tryptophan, tyrosine, MET and purine pathways, and suggest that profound biochemical alterations are linked to abnormal Ab42 and tau metabolism. Metabolomics provides powerful tools to map interlinked biochemical pathway perturbations and study AD as a disease of network failure.
[show abstract][hide abstract] ABSTRACT: Neurological and neurocognitive dysfunction occurs frequently in the large number of increasingly elderly patients undergoing cardiac surgery every year. Perioperative cognitive deficits have been shown to persist after discharge and up to several years after surgery. More importantly, perioperative cognitive decline is predictive of long-term cognitive dysfunction, reduced quality of life and increased mortality. The proposed mechanisms to explain the cognitive decline associated with cardiac surgery include the neurotoxic accumulation of β-amyloid. This study will be the first to provide molecular imaging to assess the relationship between neocortical β-amyloid deposition and postoperative cognitive dysfunction.
40 patients providing informed consent for participation in this Institutional Review Board-approved study and undergoing cardiac (coronary artery bypass graft (CABG), valve or CABG+valve) surgery with cardiopulmonary bypass will be enrolled based on defined inclusion and exclusion criteria. At 6 weeks after surgery, participants will undergo (18)F-florbetapir positron emission tomography imaging to assess neocortical β-amyloid burden along with a standard neurocognitive battery and blood testing for apolipoprotein E ε-4 genotype.
The results will be compared to those of 40 elderly controls and 40 elderly patients with mild cognitive impairment who have previously completed (18)F-florbetapir imaging.
This study has been approved by the Duke University Institutional Review Board. The results will provide novel mechanistic insights into postoperative cognitive dysfunction that will inform future studies into potential treatments or preventative therapies of long-term cognitive decline after cardiac surgery.
BMJ Open 01/2013; 3(9):e003669. · 1.58 Impact Factor
[show abstract][hide abstract] ABSTRACT: Background
Risk factors for cardiovascular disease (CVD) not only increase the risk for clinical CVD events, but also are associated with a cascade of neurophysiologic and neuroanatomic changes that increase the risk of cognitive impairment and dementia. Although epidemiological studies have shown that exercise and diet are associated with lower CVD risk and reduced incidence of dementia, no randomized controlled trial (RCT) has examined the independent effects of exercise and diet on neurocognitive function among individuals at risk for dementia. The ENLIGHTEN trial is a RCT of patients with CVD risk factors who also are characterized by subjective cognitive complaints and objective evidence of neurocognitive impairment without dementia (CIND)Study designA 2 by 2 design will examine the independent and combined effects of diet and exercise on neurocognition. 160 participants diagnosed with CIND will be randomly assigned to 6 months of aerobic exercise, the DASH diet, or a combination of both exercise and diet; a (control) group will receive health education but otherwise will maintain their usual dietary and activity habits. Participants will complete comprehensive assessments of neurocognitive functioning along with biomarkers of CVD risk including measures of blood pressure, glucose, endothelial function, and arterial stiffness.Conclusion
The ENLIGHTEN trial will (a) evaluate the effectiveness of aerobic exercise and the DASH diet in improving neurocognitive functioning in CIND patients with CVD risk factors; (b) examine possible mechanisms by which exercise and diet improve neurocognition; and (c) consider potential moderators of treatment, including subclinical CVD.
[show abstract][hide abstract] ABSTRACT: Neuropsychiatric disorders such as schizophrenia, bipolar disorder and Alzheimer's disease are major public health problems. However, despite decades of research, we currently have no validated prognostic or diagnostic tests that can be applied at an individual patient level. Many neuropsychiatric diseases are due to a combination of alterations that occur in a human brain rather than the result of localized lesions. While there is hope that newer imaging technologies such as functional and anatomic connectivity MRI or molecular imaging may offer breakthroughs, the single biomarkers that are discovered using these datasets are limited by their inability to capture the heterogeneity and complexity of most multifactorial brain disorders. Recently, complex biomarkers have been explored to address this limitation using neuroimaging data. In this manuscript we consider the nature of complex biomarkers being investigated in the recent literature and present techniques to find such biomarkers that have been developed in related areas of data mining, statistics, machine learning and bioinformatics.
[show abstract][hide abstract] ABSTRACT: Psychiatric disorders are a leading cause of disability worldwide and despite significant pharmacologic advances, often remain difficult to diagnose correctly and treat fully. Factors which contribute to these difficulties include imprecise understanding of etiology, syndromal nature of many disorders and overlap in diagnostic criteria between conditions, medical and psychiatric comorbidity and high rates of noncompliance to treatment either due to lack of efficacy or adverse effects. In addition to genetics and known biological factors, the severity and presentation of many psychiatric conditions may be influenced by psychosocial factors, which in turn can affect treatment outcomes. Currently, the selection of medications for a given patient in psychiatry is primarily based on a trial and error process; thus, there is an urgent need to identify biomarkers that can improve diagnostic homogeneity and provide useful prognostic information. Pharmacogenetics has the potential, in combination with other approaches, to enhance both care at an individual level as well as in drug development by improving efficacy and minimizing drug-induced side effects.
Expert Opinion on Drug Metabolism & Toxicology 11/2012; · 2.94 Impact Factor