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1.  Neuropsychiatric Features of Frontal Lobe Dysfunction in Autopsy-Confirmed Patients with Lewy Bodies and “Pure” Alzheimer’s Disease 
Objective
To compare patients with autopsy-confirmed Alzheimer’s disease (AD, #14) and Dementia with Lewy bodies (DLB) on the frequency of behaviors related to frontal systems dysfunction and the association of these behaviors with dementia severity.
Design
Cross-sectional survey of longitudinal cohort.
Setting
University Alzheimer’s disease research center.
Participants
Volunteer sample of 19 DLB and 38 AD participants with autopsy-confirmed diagnoses, similar in age (DLB: 77.3, AD: 77.5), education (15.2, 14.7), and Mini-Mental State Examination (MMSE) score (20.6, 20.5), with impairment ranging from mild deficits to moderate dementia.
Measurements
The Frontal Systems Behavior Scale (FrSBe)-Family Rating Form assessing patient apathy, disinhibition, and executive dysfunction by a knowledgeable informant.
Results
A two-way analysis of variance with the FrSBe total as the dependent variable revealed a significant MMSE by diagnosis interaction (F(1,53)=9.34, p=.004). Mean FrSBe total for AD patients showed significant impairment across the range of dementia severity, while it was relatively preserved for DLB patients in early stage of disease. The interaction term showed the same pattern for the executive dysfunction (F(1,53)=7.62, p=.008), disinhibition (F(1,53)=4.90, p=.031), and apathy (F(1,53)=9.77, p=.003) subscales.
Conclusions
While frontal behavioral symptoms in AD patients were present regardless of stage of dementia, DLB patients showed significant frontal dysfunction only in later stages. Results suggest that frontal subcortical circuits associated with behaviors assessed by the FrSBe are affected early in AD but not until later stages in DLB. Assessing specific behaviors related to frontal systems, coupled with stage of cognitive decline, may aid in clinical differentiation of AD and DLB.
doi:10.1016/j.jagp.2012.10.022
PMCID: PMC3664517  PMID: 23567425
Dementia with Lewy bodies; Alzheimer’s disease; Frontal systems; Behavioral symptoms
2.  C9orf72 Hexanucleotide Repeat Expansion and Guam Amyotrophic Lateral Sclerosis–Parkinsonism-Dementia Complex 
JAMA neurology  2013;70(6):742-745.
Importance
High-prevalence foci of amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia complex (PDC) exist in Japanese on the Kii Peninsula of Japan and in the Chamorros of Guam. Clinical and neuropathologic similarities suggest that the disease in these 2 populations may be related. Recent findings showed that some of the Kii Peninsula ALS cases had pathogenic C9orf72 repeat expansions, a genotype that causes ALS in Western populations.
Objectives
To perform genotyping among Guam residents to determine if the C9orf72 expanded repeat allele contributes to ALS-PDC in this population and to evaluate LRRK2 for mutations in the same population.
Design and Setting Case-control series from neurodegenerative disease research programs on Guam that screened residents for ALS, PDC, and dementia.
Participants Study participants included 24 with ALS and 22 with PDC and 43 older control subjects with normal cognition ascertained between 1956 and 2006. All but one participant were Chamorro, the indigenous people of Guam. A single individual of white race/ethnicity with ALS was ascertained on Guam during the study.
Main Outcomes and Measures Participants were screened for C9orf72 hexanucleotide repeat length. Participants with repeat numbers in great excess of 30 were considered to have pathogenic repeat expansions. LRRK2 was screened for point mutations by DNA sequencing.
Results We found a single individual with an expanded pathogenic hexanucleotide repeat. This individual of white race/ethnicity with ALS was living on Guam at the time of ascertainment but had been born in the United States. All Chamorro participants with ALS and PDC and control subjects had normal repeats, ranging from 2 to 17 copies. No pathogenic LRRK2 mutations were found.
Conclusions and Relevance Unlike participants with ALS from the Kii Peninsula, C9orf72 expansions do not cause ALS-PDC in Chamorros. Likewise, LRRK2 mutations do not cause Guam ALS-PDC.
doi:10.1001/jamaneurol.2013.1817
PMCID: PMC3771869  PMID: 23588498
3.  Effect of Knowledge of APOE Genotype on Subjective and Objective Memory Performance in Healthy Older Adults 
The American journal of psychiatry  2014;171(2):201-208.
Objective
The knowledge that one carries the apolipoprotein E (APOE) ε4 allele risk factor for Alzheimer’s disease was recently found to have little short-term psychological risk. The authors investigated the impact of knowledge of carrying the risk allele on subjective ratings of memory and objective memory test performance of older adults.
Method
Using a nested case-control design, the authors administered objective verbal and visual memory tests and self-rating scales of memory function to 144 cognitively normal older adults (ages 52–89) with known APOE genotype who knew (ε4+, N=25; ε4−, N=49) or did not know (ε4+, N=25; ε4−, N=45) their genotype and genetic risk for Alzheimer’s disease prior to neuropsychological evaluation.
Results
Significant genotype-by-disclosure interaction effects were observed on several memory rating scales and tests of immediate and delayed verbal recall. Older adults who knew their ε4+ genotype judged their memory more harshly and performed worse on an objective verbal memory test than did ε4+ adults who did not know. In contrast, older adults who knew their ε4− genotype judged their memory more positively than did ε4− adults who did not know, but these groups did not differ in objective memory test performance.
Conclusions
Informing older adults that they have an APOE genotype associated with an increased risk of Alzheimer’s disease can have adverse consequences on their perception of their memory abilities and their performance on objective memory tests. The patient’s knowledge of his or her genotype and risk of Alzheimer’s disease should be considered when evaluating cognition in the elderly.
doi:10.1176/appi.ajp.2013.12121590
PMCID: PMC4037144  PMID: 24170170
4.  Interrater reliability of the new criteria for behavioral variant frontotemporal dementia 
Neurology  2013;80(21):1973-1977.
Objective:
To evaluate the interrater reliability of the new International Behavioural Variant FTD Criteria Consortium (FTDC) criteria for behavioral variant frontotemporal dementia (bvFTD).
Methods:
Twenty standardized clinical case modules were developed for patients with a range of neurodegenerative diagnoses, including bvFTD, primary progressive aphasia (nonfluent, semantic, and logopenic variant), Alzheimer disease, and Lewy body dementia. Eighteen blinded raters reviewed the modules and 1) rated the presence or absence of core diagnostic features for the FTDC criteria, and 2) provided an overall diagnostic rating. Interrater reliability was determined by κ statistics for multiple raters with categorical ratings.
Results:
The mean κ value for diagnostic agreement was 0.81 for possible bvFTD and 0.82 for probable bvFTD (“almost perfect agreement”). Interrater reliability for 4 of the 6 core features had “substantial” agreement (behavioral disinhibition, perseverative/compulsive, sympathy/empathy, hyperorality; κ = 0.61–0.80), whereas 2 had “moderate” agreement (apathy/inertia, neuropsychological; κ = 0.41–0.6). Clinician years of experience did not significantly influence rater accuracy.
Conclusions:
The FTDC criteria show promise for improving the diagnostic accuracy and reliability of clinicians and researchers. As disease-altering therapies are developed, accurate differential diagnosis between bvFTD and other neurodegenerative diseases will become increasingly important.
doi:10.1212/WNL.0b013e318293e368
PMCID: PMC3716343  PMID: 23635967
5.  STIMULATED PLATELETS RELEASE AMYLOID β–PROTEIN PRECURSOR 
Human platelets can be stimulated by thrombin or ionomycin to secrete soluble truncated amyloid β–protein precursor and particulate membrane fragments which contain C-terminal and N-terminal immunoreactive amyloid β–protein precursor. This suggests a possible circulating source of β–protein in serum which may play a role in the formation of amyloid deposits. The release of soluble amyloid β-protein precursor could be involved in normal platelet physiology.
PMCID: PMC4019003  PMID: 2115331
6.  GWAS of cerebrospinal fluid tau levels identifies novel risk variants for Alzheimer’s disease 
Neuron  2013;78(2):256-268.
Cerebrospinal fluid (CSF) tau, tau phosphorylated at threonine 181 (ptau) and Aβ42 are established biomarkers for Alzheimer’s Disease (AD), and have been used as quantitative traits for genetic analyses. We performed the largest genome-wide association study for cerebrospinal fluid (CSF) tau/ptau levels published to date (n=1,269), identifying three novel genome-wide significant loci for CSF tau and ptau: rs9877502 (P=4.89×10−9 for tau) located at 3q28 between GEMC1 and OSTN, rs514716 (P=1.07×10−8 and P=3.22×10−9 for tau and ptau respectively), located at 9p24.2 within GLIS3 and rs6922617 (P = 3.58×10−8 for CSF ptau) at 6p21.1 within the TREM gene cluster, a region recently reported to harbor rare variants that increase AD risk. In independent datasets rs9877502 showed a strong association with risk for AD, tangle pathology and global cognitive decline (P=2.67×10−4, 0.039, 4.86×10−5 respectively) illustrating how this endophenotype-based approach can be used to identify new AD risk loci.
doi:10.1016/j.neuron.2013.02.026
PMCID: PMC3664945  PMID: 23562540
7.  PET imaging of amyloid with Florbetapir F 18 and PET imaging of dopamine degeneration with 18F-AV-133 (florbenazine) in patients with Alzheimer’s disease and Lewy body disorders 
BMC Neurology  2014;14:79.
Background
Biomarkers based on the underlying pathology of Alzheimer’s disease (AD) and Dementia with Lewy Bodies (DLB) have the potential to improve diagnosis and understanding of the substrate for cognitive impairment in these disorders. The objective of this study was to compare the patterns of amyloid and dopamine PET imaging in patients with AD, DLB and Parkinson’s disease (PD) using the amyloid imaging agent florbetapir F 18 and 18F-AV-133 (florbenazine), a marker for vesicular monamine type 2 transporters (VMAT2).
Methods
Patients with DLB and AD, Parkinson’s disease (PD) and healthy controls (HC) were recruited for this study. On separate days, subjects received intravenous injections of florbetapir, and florbenazine. Amyloid burden and VMAT2 density were assessed quantitatively and by binary clinical interpretation. Imaging results for both tracers were compared across the four individual diagnostic groups and for combined groups based on underlying pathology (AD/DLB vs. PD/HC for amyloid burden and PD/DLB vs. AD/HC for VMAT binding) and correlated with measures of cognition and parkinsonism.
Results
11 DLB, 10 AD, 5 PD, and 5 controls participated in the study. Amyloid binding was significantly higher in the combined AD/DLB patient group (n = 21) compared to the PD/HC groups (n = 10, mean SUVr: 1.42 vs. 1.07; p = 0.0006). VMAT2 density was significantly lower in the PD/DLB group (n = 16) compared to the AD/ HC group (n = 15; 1.83 vs. 2.97; p < 0.0001). Within the DLB group, there was a significant correlation between cognitive performance and striatal florbenazine binding (r = 0.73; p = 0.011).
Conclusions
The results of this study show significant differences in both florbetapir and florbenazine imaging that are consistent with expected pathology. In addition, VMAT density correlated significantly with cognitive impairment in DLB patients (ClinicalTrials.gov identifier: NCT00857506, registered March 5, 2009).
doi:10.1186/1471-2377-14-79
PMCID: PMC4027995  PMID: 24716655
PET imaging; Alzheimer’s disease; Parkinson’s disease; Biomarkers
8.  Effect of TTP488 in patients with mild to moderate Alzheimer’s disease 
BMC Neurology  2014;14:12.
Background
TTP488, an antagonist at the Receptor for Advanced Glycation End products, was evaluated as a potential treatment for patients with mild-to-moderate Alzheimer’s disease (AD). A previous report describes decreased decline in ADAS-cog (delta = 3.1, p = 0.008 at 18 months, ANCOVA with multiple imputation), relative to placebo, following a 5 mg/day dose of TTP488. Acute, reversible cognitive worsening was seen with a 20 mg/day dose. The present study further evaluates the efficacy of TTP488 by subgroup analyses based on disease severity and concentration effect analysis.
Methods
399 patients were randomized to one of two oral TTP488 doses (60 mg for 6 days followed by 20 mg/day; 15 mg for 6 days followed by 5 mg/day) or placebo for 18 months. Pre-specified primary analysis, using an ITT population, was on the ADAS-cog11. Secondary analyses included as a key secondary variable the Clinical Dementia Rating-Sum of Boxes (CDR-SB), and another secondary variable of the ADCS-ADL.
Results
On-treatment analysis demonstrated numerical differences favoring 5 mg/day over placebo, with nominal significance at Month 18 (delta = 2.7, p = 0.03). Patients with mild AD, whether defined by MMSE or ADAS-cog, demonstrated significant differences favoring 5 mg/day on ADAS-cog and trends on CDR-sb and ADCS-ADL at Month 18. TTP488 plasma concentrations of 7.6-16.8 ng/mL were associated with a decreased decline in ADAS-cog over time compared to placebo. Worsening on the ADAS-cog relative to placebo was evident at 46.8-167.0 ng/mL.
Conclusions
Results of these analyses support further investigation of 5 mg/day in future Phase 3 trials in patients with mild AD.
doi:10.1186/1471-2377-14-12
PMCID: PMC4021072  PMID: 24423155
9.  Effects of Baseline CSF α-Synuclein on Regional Brain Atrophy Rates in Healthy Elders, Mild Cognitive Impairment and Alzheimer’s Disease 
PLoS ONE  2013;8(12):e85443.
Background
Cerebrospinal fluid (CSF) α-synuclein is reduced in synucleinopathies, including dementia with Lewy bodies, and some studies have found increased CSF α-synuclein in Alzheimer’s disease (AD). No study has explored effects of CSF α-synuclein on brain atrophy. Here we tested if baseline CSF α-synuclein affects brain atrophy rates and if these effects vary across brain regions, and across the cognitive spectrum from healthy elders (NL), to patients with mild cognitive impairment (MCI) and AD.
Methods
Baseline CSF α-synuclein measurements and longitudinal structural brain magnetic resonance imaging was performed in 74 NL, 118 MCI patients and 55 AD patients. Effects of baseline CSF α-synuclein on regional atrophy rates were tested in 1) four pre-hoc defined regions possibly associated with Lewy body and/or AD pathology (amygdala, caudate, hippocampus, brainstem), and 2) all available regions of interest. Differences across diagnoses were tested by assessing the interaction of CSF α-synuclein and diagnosis (testing NL versus MCI, and NL versus AD).
Results
The effects of CSF α-synuclein on longitudinal atrophy rates were not significant after correction for multiple comparisons. There were tendencies for effects in AD in caudate (higher atrophy rates in subjects with higher CSF α-synuclein, P=0.046) and brainstem (higher atrophy rates in subjects with lower CSF α-synuclein, P=0.063). CSF α-synuclein had significantly different effects on atrophy rates in NL and AD in brainstem (P=0.037) and caudate (P=0.006).
Discussion: With the possible exception of caudate and brainstem, the overall weak effects of CSF α-synuclein on atrophy rates in NL, MCI and AD argues against CSF α-synuclein as a biomarker related to longitudinal brain atrophy in these diagnostic groups. Any effects of CSF α-synuclein may be attenuated by possible simultaneous occurrence of AD-related neuronal injury and concomitant Lewy body pathology, which may elevate and reduce CSF α-synuclein levels, respectively.
doi:10.1371/journal.pone.0085443
PMCID: PMC3877372  PMID: 24392009
11.  Higher Education is Not Associated with Greater Cortical Thickness in Brain Areas Related to Literacy or Intelligence in Normal Aging or Mild Cognitive Impairment 
Education may reduce risk of dementia through passive reserve, by increasing neural substrate. We tested the hypotheses that education is associated with thicker cortex and reduced rates of atrophy in brain regions related to literacy and intellectual ability. Healthy older adults and those with mild cognitive impairment were categorized into High (≥18 yrs) and Low (≤13 yrs) education groups. Higher education was associated with thinner cortices in several areas, but one-year atrophy rates in these areas did not differ by education group. These results do not support a passive reserve model in which early life education protects against dementia by increasing cortical thickness. Connectivity and synaptic efficiency, or other lifestyle factors may more directly reflect cognitive reserve.
doi:10.1080/13803395.2012.702733
PMCID: PMC3488147  PMID: 22905705
Brain reserve; cortical thickness; education; hippocampal volume; literacy; Mild Cognitive Impairment (MCI); aging
12.  Biomarkers for Alzheimer's disease in plasma, serum and blood - conceptual and practical problems 
Substances produced throughout the body are detectable in the blood, which is the most common biological fluid used in clinical testing. Biomarkers for Alzheimer's disease (AD) have long been sought in the blood, but none has become an established or validated diagnostic test. Companion reviews in Alzheimer's Research & Therapy will review specific types of biomarkers or applications; in this overview, we cover key concepts related to AD blood biomarker studies in general. Reasons for the difficulty of detecting markers of a brain-specific disorder, such as AD, in the blood are outlined; these pose conceptual challenges for blood biomarker discovery and development. Applications of blood tests in AD go beyond screening and diagnostic testing; other potential uses are risk assessment, prognostication, and evaluation of treatment target engagement, toxicity, and outcome. Opportunities and questions that may surround these different uses are discussed. A systematic approach to biomarker discovery, detection, assay development and quality control, sample collection, handling and storage, and design and analysis of clinical studies needs to be implemented at every step of discovery and translation to identify an interpretable and useful biomarker.
doi:10.1186/alzrt164
PMCID: PMC3706797  PMID: 23470193
13.  Early Visuospatial Deficits Predict the Occurrence of Visual Hallucinations in Autopsy-Confirmed Dementia with Lewy Bodies 
Objectives
The current study explored the value of visuospatial findings for predicting the occurrence of visual hallucinations (VH) in a sample of patients with Dementia with Lewy bodies (DLB) compared to patients with Alzheimer’s disease (AD).
Participants/Measurements
Retrospective analysis of 55 autopsy-confirmed DLB and 55 demographically-similar, autopsy-confirmed AD cases determined whether severe initial visuospatial deficits on the WISC-R Block Design subtest predicted the development of VH. Visuospatial deficits were considered severe if Block Design z-scores were 2.5 or more standard deviations below the mean of a well-characterized normal control group (Severe-VIS; DLB: n=35, AD: n=26) and otherwise were considered mild (Mild-VIS; DLB: n=20, AD: n=29).
Results
Forty percent of the Severe-VIS DLB group had baseline VH compared to 0% of Mild-VIS DLB patients. Only 8% of the Severe-VIS and 3% Mild-VIS AD patients had baseline VH. During the follow-up period (mean=5.0 years), an additional 61% of the Severe-VIS but only 11% of the Mild-VIS DLB patients developed VH. In that period, 38% of the Severe-VIS and 20% of the Mild-VIS AD patients developed VH. After considering initial MMSE score and rate of decline, logistic regression analyses found that performance on Block Design significantly predicted the presence of VH in the DLB group but not the AD group.
Conclusions
The presence of early, severe deficits on neuropsychological tests of visuospatial skill increases the likelihood that patients with suspected DLB will develop the prototypical DLB syndrome. The presence of such deficits may identify those DLB patients whose syndrome is driven by alpha-synuclein pathology rather than AD pathology and may inform treatment plans as well as future research.
doi:10.1097/JGP.0b013e31823033bc
PMCID: PMC3260388  PMID: 21997600
Lewy body disease; Hallucinations, visual; Alzheimer’s disease; Visuospatial cognition
14.  Potential Use of γ-Secretase Modulators in the Treatment of Alzheimer Disease 
Archives of neurology  2012;69(10):1255-1258.
Although significant progress has occurred in the past 20 years regarding our understanding of Alzheimer disease pathogenesis, we have yet to identify disease-modifying therapeutics capable of substantially altering the clinical course of this prevalent neurodegenerative disease. In this short review, we discuss 2 approaches that are currently being tested clinically (γ-secretase inhibition and γ-secretase modulation) and emphasize the significant differences between these 2 therapeutic approaches. We also discuss certain genetic- and biomarker-based translational and clinical trial paradigms that may assist in developing a useful therapeutic agent.
doi:10.1001/archneurol.2012.540
PMCID: PMC3747667  PMID: 22801784
15.  Temporal Sequence Learning in Healthy Aging and Amnestic Mild Cognitive Impairment 
Experimental aging research  2013;39(4):371-381.
Background/Study Context
Temporal sequence learning is a critical aspect of episodic memory that may be dependent on the temporal and frontal lobes. Since amnestic mild cognitive impairment (aMCI) and normal aging may result in changes within the temporal and frontal lobes, the present study investigated temporal sequence learning in patients with aMCI, cognitively normal older adults, and young adults.
Methods
On each trial of a temporal sequence task, circles appeared one at a time at the end of each arm of a computerized radial 8-arm maze. Participants were asked to reproduce the temporal sequence by placing numbered circles (1-8) on the arms of the 8-arm maze. Participants were presented with the same fixed sequence on each trial until the sequence was replicated without any errors, or until 15 trials were presented.
Results
Individuals with aMCI required significantly more trials to learn the temporal sequence compared to older adults (p <. 05). Older adults required significantly more trials to learn the sequence than young adults (p <. 05). Older adults and individuals with aMCI committed significantly more Trial 1 errors (p <. 05) than young adults; however, there were no significant differences between the aMCI and older adult groups on Trial 1.
Conclusion
The results suggest that temporal sequence learning deficits are detectable in aMCI. These deficits may disrupt a number of cognitive processes, such as episodic memory, that are important for the execution of daily activities. The results suggest that although temporal sequence learning declines with normal aging, this decline is greater in individuals who have a diagnosis of aMCI and are at higher risk for developing AD.
doi:10.1080/0361073X.2013.808122
PMCID: PMC3736698  PMID: 23875836
16.  Distinctive patterns of DNA methylation associated with Parkinson disease 
Epigenetics  2013;8(10):1030-1038.
Parkinson disease (PD) is a multifactorial neurodegenerative disorder with high incidence in the elderly, where environmental and genetic factors are involved in etiology. In addition, epigenetic mechanisms, including deregulation of DNA methylation have been recently associated to PD. As accurate diagnosis cannot be achieved pre-mortem, identification of early pathological changes is crucial to enable therapeutic interventions before major neuropathological damage occurs. Here we investigated genome-wide DNA methylation in brain and blood samples from PD patients and observed a distinctive pattern of methylation involving many genes previously associated to PD, therefore supporting the role of epigenetic alterations as a molecular mechanism in neurodegeneration. Importantly, we identified concordant methylation alterations in brain and blood, suggesting that blood might hold promise as a surrogate for brain tissue to detect DNA methylation in PD and as a source for biomarker discovery.
doi:10.4161/epi.25865
PMCID: PMC3891683  PMID: 23907097
DNA methylation; Parkinson disease; brain; peripheral blood leukocytes; epigenetics; neurodegeneration; genome-wide methylation
17.  The Alzheimer’s Association external quality control program for cerebrospinal fluid biomarkers 
Mattsson, Niklas | Andreasson, Ulf | Persson, Staffan | Arai, Hiroyuki | Batish, Sat Dev | Bernardini, Sergio | Bocchio-Chiavetto, Luisella | Blankenstein, Marinus A. | Carrillo, Maria C. | Chalbot, Sonia | Coart, Els | Chiasserini, Davide | Cutler, Neal | Dahlfors, Gunilla | Duller, Stefan | Fagan, Anne M. | Forlenza, Orestes | Frisoni, Giovanni B. | Galasko, Douglas | Galimberti, Daniela | Hampel, Harald | Handberg, Aase | Heneka, Michael T. | Herskovits, Adrianna Z. | Herukka, Sanna-Kaisa | Holtzman, David M. | Humpel, Christian | Hyman, Bradley T. | Iqbal, Khalid | Jucker, Mathias | Kaeser, Stephan A. | Kaiser, Elmar | Kapaki, Elisabeth | Kidd, Daniel | Klivenyi, Peter | Knudsen, Cindy S. | Kummer, Markus P. | Lui, James | Lladó, Albert | Lewczuk, Piotr | Li, Qiao-Xin | Martins, Ralph | Masters, Colin | McAuliffe, John | Mercken, Marc | Moghekar, Abhay | Molinuevo, José Luis | Montine, Thomas J. | Nowatzke, William | O’Brien, Richard | Otto, Markus | Paraskevas, George P. | Parnetti, Lucilla | Petersen, Ronald C. | Prvulovic, David | de Reus, Herman P. M. | Rissman, Robert A. | Scarpini, Elio | Stefani, Alessandro | Soininen, Hilkka | Schröder, Johannes | Shaw, Leslie M. | Skinningsrud, Anders | Skrogstad, Brith | Spreer, Annette | Talib, Leda | Teunissen, Charlotte | Trojanowski, John Q. | Tumani, Hayrettin | Umek, Robert M. | Van Broeck, Bianca | Vanderstichele, Hugo | Vecsei, Laszlo | Verbeek, Marcel M. | Windisch, Manfred | Zhang, Jing | Zetterberg, Henrik | Blennow, Kaj
Background
The cerebrospinal fluid (CSF) biomarkers amyloid β (Aβ)-42, total-tau (T-tau), and phosphorylated-tau (P-tau) demonstrate good diagnostic accuracy for Alzheimer’s disease (AD). However, there are large variations in biomarker measurements between studies, and between and within laboratories. The Alzheimer’s Association has initiated a global quality control program to estimate and monitor variability of measurements, quantify batch-to-batch assay variations, and identify sources of variability. In this article, we present the results from the first two rounds of the program.
Methods
The program is open for laboratories using commercially available kits for Aβ, T-tau, or P-tau. CSF samples (aliquots of pooled CSF) are sent for analysis several times a year from the Clinical Neurochemistry Laboratory at the Molndal campus of the University of Gothenburg, Sweden. Each round consists of three quality control samples.
Results
Forty laboratories participated. Twenty-six used INNOTESTenzyme-linked immunosorbent assay kits, 14 used Luminex xMAP with the INNO-BIA AlzBio3 kit (both measure Aβ-(1-42), P-tau(181P), and T-tau), and 5 used Meso Scale Discovery with the Aβ triplex (AβN-42, AβN-40, and AβN-38) or T-tau kits. The total coefficients of variation between the laboratories were 13% to 36%. Five laboratories analyzed the samples six times on different occasions. Within-laboratory precisions differed considerably between biomarkers within individual laboratories.
Conclusions
Measurements of CSF AD biomarkers show large between-laboratory variability, likely caused by factors related to analytical procedures and the analytical kits. Standardization of laboratory procedures and efforts by kit vendors to increase kit performance might lower variability, and will likely increase the usefulness of CSF AD biomarkers.
doi:10.1016/j.jalz.2011.05.2243
PMCID: PMC3710290  PMID: 21784349
Alzheimer’s disease; Cerebrospinal fluid; Biomarkers; External assurance; External control; Proficiency testing
18.  The Influence of Chronic Stress on Dementia-Related Diagnostic Change in Older Adults 
Increased susceptibility of the aging brain to both chronic stress and incipient dementia-related neuropathology may accelerate cognitive decline. We investigated associations between chronic stress and diagnostic change in 62 individuals (mean age=78.7) participating in an Alzheimer’s disease research center longitudinal study. Subjects, diagnosed at baseline as cognitively normal (CN) or Mild Cognitive Impairment (MCI) were followed an average of 2.5 years. Senior neurologists, blind to detailed measures of stress and cognition, assigned diagnoses annually. Logistic regression analyses assessed accuracy with which measures of stress (event-based ratings, cortisol levels) predicted conversion to MCI and dementia. Eleven individuals with MCI at baseline received a dementia diagnosis during follow-up. Sixteen converted from CN to MCI. Prolonged, highly stressful experiences were associated with conversion from MCI to dementia. The cortisol awakening response, with age and education, was associated with diagnostic change to MCI. Cortisol measures were not associated with progression from MCI to dementia, and there was no association between stressful experiences and change to MCI. Mechanisms associated with the transition from normal cognition to MCI may differ from those associated with diagnostic change to dementia. These findings could facilitate identification of interventional strategies to reduce risk of decline at different stages of susceptibility.
doi:10.1097/WAD.0b013e3182389a9c
PMCID: PMC3290680  PMID: 22037597
chronic stress; aging; Alzheimer’s disease; mild cognitive impairment; dementia; diurnal rhythm; cortisol awakening response
19.  Antioxidants for Alzheimer Disease 
Archives of neurology  2012;69(7):836-841.
Objective
To evaluate whether antioxidant supplements presumed to target specific cellular compartments affected cerebrospinal fluid (CSF) biomarkers.
Design
Double-blind, placebo-controlled clinical trial.
Setting
Academic medical centers.
Participants
Subjects with mild to moderate Alzheimer disease.
Intervention
Random assignment to treatment for 16 weeks with 800 IU/d of vitamin E (α-tocopherol) plus 500 mg/d of vitamin C plus 900 mg/d of α-lipoic acid (E/C/ALA); 400 mg of coenzyme Q 3 times/d; or placebo.
Main Outcome Measures
Changes from baseline to 16 weeks in CSF biomarkers related to Alzheimer disease and oxidative stress, cognition (Mini-Mental State Examination), and function (Alzheimer’s Disease Cooperative Study Activities of Daily Living Scale).
Results
Seventy-eight subjects were randomized; 66 provided serial CSF specimens adequate for biochemical analyses. Study drugs were well tolerated, but accelerated decline in Mini-Mental State Examination scores occurred in the E/C/ALA group, a potential safety concern. Changes in CSF Aβ42, tau, and P-tau181 levels did not differ between the 3 groups. Cerebrospinal fluid F2-isoprostane levels, an oxidative stress biomarker, decreased on average by 19% from baseline to week 16 in the E/C/ALA group but were unchanged in the other groups.
Conclusions
Antioxidants did not influence CSF biomarkers related to amyloid or tau pathology. Lowering of CSF F2-isoprostane levels in the E/C/ALA group suggests reduction of oxidative stress in the brain. However, this treatment raised the caution of faster cognitive decline, which would need careful assessment if longer-term clinical trials are conducted.
Trial Registration
clinicaltrials.gov Identifier: NCT00117403
PMCID: PMC3661272  PMID: 22431837
20.  Incidence of New-Onset Seizures in Mild to Moderate Alzheimer Disease 
Archives of neurology  2012;69(3):368-372.
Objective
To estimate the incidence rate and predictors of seizures in patients with mild to moderate Alzheimer disease (AD).
Design
Cohort study of patients with mild to moderate AD in clinical trials. Risk factors for potential seizures were evaluated by stratified descriptive statistics and univariable and multivariable Cox proportional hazards regressions.
Setting
Pooled patient-level data from 10 Alzheimer Disease Cooperative Study clinical trials in mild to moderate AD from 1995 to 2010.
Patients
Three thousand seventy-eight subjects randomized to the treatment or placebo arms of 10 AD clinical trials. Screening Mini-Mental State Examination scores ranged between 10 and 28.
Results
Eighteen seizures were reported in 3078 randomized subjects, with an incidence rate of 484 per 100 000 person-years (95% CI, 287–764). Statistically significant independent risk factors for seizure were younger age (adjusted hazard ratio, 0.80; 95% CI, 0.69–0.93 per every 5 years of age), greater cognitive impairment at baseline (adjusted hazard ratio, 2.79; 95% CI, 1.06–7.33 for Mini-Mental State Examination scores <18 compared with Mini-Mental State Examination scores ≥18), and antipsychotic use at baseline (adjusted hazard ratio, 3.47; 95% CI, 1.33–9.08).
Conclusions
Seizure rates in patients with mild to moderate AD in clinical trials are similar to rates observed in longer observational cohort studies, but they are greater than expected in the general elderly population. Younger age, greater degree of cognitive impairment, and history of antipsychotic use were independent risk factors for new-onset seizures in AD.
doi:10.1001/archneurol.2011.830
PMCID: PMC3622046  PMID: 22410444
21.  Comparison of the Memory Performance Index With Standard Neuropsychological Measures of Cognition 
The Mild Cognitive Impairment Screen (MCIS) is a computer-based cognitive assessment designed for clinical and research use in detecting amnestic mild cognitive impairment (aMCI). Performance on the MCIS is reported as the Memory Performance Index (MPI). However, the comparability between the MPI and traditional neuropsychological tests in detecting aMCI, and in differentiating it from Alzheimer’s disease (AD) and normal aging has not been examined. A cross-sectional study was conducted to assess the validity of the MPI relative to standard neuropsychological measures. Participants included 12 individuals diagnosed with aMCI, 49 with mild AD, and 25 healthy elderly. The MCIS significantly discriminated among aMCI, AD, and healthy elderly controls. The MCIS is effective in detecting aMCI, and in discriminating it from cognitive changes observed in AD and normal aging. The MCIS may be a valuable tool in the identification of elderly at high risk for dementia due to its ease-of-use and brief administration time.
doi:10.1177/1533317511402316
PMCID: PMC3568924  PMID: 21406427
Mild Cognitive Impairment; Dementia; Alzheimer’s Disease; Screening; Memory
22.  TARDBP mutations in amyotrophic lateral sclerosis with TDP-43 neuropathology: a genetic and histopathological analysis 
Lancet neurology  2008;7(5):409-416.
SUMMARY
BACKGROUND
TDP-43 is a major component of the ubiquitinated inclusions that characterise amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) with ubiquitin inclusions (FTLD-U). TDP-43 is an RNA-binding and DNA-binding protein that has many functions and is encoded by the TAR DNA-binding protein gene (TARDBP) on chromosome 1. Our aim was to investigate whether TARDBP is a candidate disease gene for familial ALS that is not associated with mutations in superoxide dismutase 1 (SOD1).
METHODS
TARDBP was sequenced in 259 patients with ALS, FTLD, or both. We used TaqMan-based SNP genotyping to screen for the identifi ed variants in control groups matched to two kindreds of patients for age and ethnic origin. Additional clinical, genetic, and pathological assessments were made in these two families.
FINDINGS
We identified two variants, p.Gly290Ala and p.Gly298Ser, in TARDBP in two familial ALS kindreds and we observed TDP-43 neuropathology in the CNS tissue available from one family. The variants are considered pathogenic mutations because they co-segregate with disease in both families, are absent in ethnically-matched controls, and are associated with TDP-43 neuropathology in several family members.
INTERPRETATION
The p.Gly290Ala and p.Gly298Ser mutations are located in the glycine-rich domain that regulates gene expression and mediates protein-protein interactions; in particular TDP-43 binds to heterogeneous ribonucleoproteins (hnRNPs) via this domain. We postulate that due to the varied and important cellular functions of TDP-43, these mutations may cause neurodegeneration through both gains and losses of function. The finding of TARDBP mutations implicates TDP-43 as an active mediator of neurodegeneration in a novel class of disorders, TDP-43 proteinopathies, a class of disorder that includes ALS and FTLD-U.
doi:10.1016/S1474-4422(08)70071-1
PMCID: PMC3546119  PMID: 18396105
23.  Degree of Bilingualism Predicts Age of Diagnosis of Alzheimer’s Disease in Low-Education but not in Highly-Educated Hispanics 
Neuropsychologia  2011;49(14):3826-3830.
The current study investigated the relationship between bilingual language proficiency and onset of probable Alzheimer’s disease (AD) in 44 Spanish-English bilinguals at the UCSD Alzheimer’s Disease Research Center. Degree of bilingualism along a continuum was measured using Boston Naming Test (BNT) scores in each language. Higher degrees of bilingualism were associated with increasingly later age-of-diagnosis (and age of onset of symptoms), but this effect was driven by participants with low education level (a significant interaction between years of education and bilingualism) most of whom (73%) were also Spanish-dominant. Additionally, only objective measures (i.e., BNT scores), not self-reported degree of bilingualism, predicted age-of-diagnosis even though objective and self-reported measures were significantly correlated. These findings establish a specific connection between knowledge of two languages and delay of AD onset, and demonstrate that bilingual effects can be obscured by interactions between education and bilingualism, and by failure to obtain objective measures of bilingualism. More generally, these data support analogies between the effects of bilingualism and “cognitive reserve” and suggest an upper limit on the extent to which reserve can function to delay dementia.
doi:10.1016/j.neuropsychologia.2011.09.041
PMCID: PMC3223277  PMID: 22001315
24.  Recent Alzheimer's disease research highlights 
doi:10.1186/alzrt117
PMCID: PMC3506929  PMID: 22594696
25.  Sensitivity of revised diagnostic criteria for the behavioural variant of frontotemporal dementia 
Brain  2011;134(9):2456-2477.
Based on the recent literature and collective experience, an international consortium developed revised guidelines for the diagnosis of behavioural variant frontotemporal dementia. The validation process retrospectively reviewed clinical records and compared the sensitivity of proposed and earlier criteria in a multi-site sample of patients with pathologically verified frontotemporal lobar degeneration. According to the revised criteria, ‘possible’ behavioural variant frontotemporal dementia requires three of six clinically discriminating features (disinhibition, apathy/inertia, loss of sympathy/empathy, perseverative/compulsive behaviours, hyperorality and dysexecutive neuropsychological profile). ‘Probable’ behavioural variant frontotemporal dementia adds functional disability and characteristic neuroimaging, while behavioural variant frontotemporal dementia ‘with definite frontotemporal lobar degeneration’ requires histopathological confirmation or a pathogenic mutation. Sixteen brain banks contributed cases meeting histopathological criteria for frontotemporal lobar degeneration and a clinical diagnosis of behavioural variant frontotemporal dementia, Alzheimer’s disease, dementia with Lewy bodies or vascular dementia at presentation. Cases with predominant primary progressive aphasia or extra-pyramidal syndromes were excluded. In these autopsy-confirmed cases, an experienced neurologist or psychiatrist ascertained clinical features necessary for making a diagnosis according to previous and proposed criteria at presentation. Of 137 cases where features were available for both proposed and previously established criteria, 118 (86%) met ‘possible’ criteria, and 104 (76%) met criteria for ‘probable’ behavioural variant frontotemporal dementia. In contrast, 72 cases (53%) met previously established criteria for the syndrome (P < 0.001 for comparison with ‘possible’ and ‘probable’ criteria). Patients who failed to meet revised criteria were significantly older and most had atypical presentations with marked memory impairment. In conclusion, the revised criteria for behavioural variant frontotemporal dementia improve diagnostic accuracy compared with previously established criteria in a sample with known frontotemporal lobar degeneration. Greater sensitivity of the proposed criteria may reflect the optimized diagnostic features, less restrictive exclusion features and a flexible structure that accommodates different initial clinical presentations. Future studies will be needed to establish the reliability and specificity of these revised diagnostic guidelines.
doi:10.1093/brain/awr179
PMCID: PMC3170532  PMID: 21810890
behavioural variant frontotemporal dementia; diagnostic criteria; frontotemporal lobar degeneration; FTD; pathology

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