The Alzheimer variant of Lewy body disease: A pathologically confirmed case-control study

The objective of the study was to identify clinical features that distinguish patients with dementia with Lewy bodies (DLB), who were classified as Alzheimer's disease ( AD) patients, from patients with AD. We examined a group of 27 patients from our memory clinic, originally diagnosed with AD, of whom 6 were postmortem found to have DLB. For the present study, we compared cognitive, noncognitive and neurological symptoms between the two groups. We found that there were no differences on ratings of dementia and scales for activities of daily living. Patients with DLB performed better on the MMSE and the memory subtest of the CAMCOG, but there was no difference in any other cognitive domain. Furthermore, genetic risk factors, including family history of dementia or allele frequency of the apolipoprotein epsilon 4, did not discriminate between the two groups, and there were no differences on CCT scans. Taken together, our findings suggest that Lewy body pathology may be present in patients who do not show the typical clinical features which distinguish DLB from AD. Copyright (C) 2005 S. Karger AG, Basel

Paramnestic reduplication of Charles Bonnet and Theophile Bonet

An elderly woman developed the delusion that she was dead (‘Cotard's delusion’) and that she was in another place (‘reduplicative paramnesia’). Charles Bonnet reported this unique combination of symptoms a century before Cotard's influential description of the nihilistic delusions and of Pick's description of ‘reduplicative paramnesia’

Why Is It So Difficult to Evaluate Nursing Interventions in Dementia?

Two recent health technology assessment (HTA) reports published in Germany focused on non-pharmacological interventions for patients with dementia. One of the major results was the poor methodological quality of the studies in this field. This paper concisely presents the main quantitative and qualitative findings of the HTA report published by the German Agency for HTA at the Institute of Medical Information and Documentation (dahta@DIMDI), followed by a detailed discussion of the major methodological problems observed for the inclusion criteria, interventions, the setting, number of patients included, duration of observation, comparators, clinical endpoints, health economics, and, most obvious, the impossibility of blinding and eliminating placebo effects for future clinical studies. We conclude with several suggestions addressing these challenges for future research in this field

Age-correction of test scores reduces the validity of mild cognitive impairment in predicting progression to dementia

Objectives: A phase of mild cognitive impairment (MCI) precedes most forms of neurodegenerative dementia. Many definitions of MCI recommend the use of test norms to diagnose cognitive impairment. It is, however, unclear whether the use of norms actually improves the detection of individuals at risk of dementia. Therefore, the effects of age- and education-norms on the validity of test scores in predicting progression to dementia were investigated. Methods: Baseline cognitive test scores (Syndrome Short Test) of dementia-free participants aged >= 65 were used to predict progression to dementia within three years. Participants were comprehensively examined one, two, and three years after baseline. Test scores were calculated with correction for (1) age and education, (2) education only, (3) age only and (4) without correction. Predictive validity was estimated with Cox proportional hazard regressions. Areas under the curve (AUCs) were calculated for the one-, two-, and three- year intervals. Results: 82 (15.3%) of initially 537 participants, developed dementia. Model coefficients, hazard ratios, and AUCs of all scores were significant (p<0.001). Predictive validity was the lowest with age-corrected scores (-2 log likelihood = 840.90, model fit chi(2) (1) = 144.27, HR = 1.33, AUCs between 0.73 and 0.87) and the highest with education-corrected scores (-2 log likelihood = 815.80, model fit chi(2) (1) = 171.16, HR = 1.34, AUCs between 0.85 and 0.88). Conclusion: The predictive validity of test scores is markedly reduced by age-correction. Therefore, definitions of MCI should not recommend the use of age-norms in order to improve the detection of individuals at risk of dementia

Predicting dementia in primary care patients with a cardiovascular health metric: a prospective population-based study

Background: Improving cardiovascular health possibly decreases the risk of dementia. Primary care practices offer a suitable setting for monitoring and controlling cardiovascular risk factors in the older population. The purpose of the study is to examine the association of a cardiovascular health metric including six behaviors and blood parameters with the risk of dementia in primary care patients. Methods: Participants (N = 3547) were insurants aged >= 55 of the largest German statutory health insurance company, who were enrolled in a six-year prospective population-based study. Smoking, physical activity, body mass index, blood pressure, total cholesterol, and fasting glucose were assessed by general practitioners at routine examinations. Using recommended cut-offs for each factor, the patients' cardiovascular health was classified as ideal, moderate, or poor. Behaviors and blood parameters sub-scores, as well as a total score, were calculated. Dementia diagnoses were retrieved from health insurance claims data. Results are presented as hazard ratios (HRs) and 95 % confidence intervals (95 % CIs). Results: Over the course of the study 296 new cases of dementia occurred. Adjusted for age, sex, and education, current smoking (HR = 1.77, 95 % CI 1.09-2.85), moderate (1.38, 1.05-1.81) or poor (1.81, 1.32-2.47) levels of physical activity, and poor fasting glucose levels (1.43, 1.02-2.02) were associated with an increased risk of dementia. Body mass index, blood pressure, and cholesterol were not associated with dementia. Separate summary scores for behaviors and blood values, as well as a total score showed no association with dementia. Sensitivity analyses with differently defined endpoints led to similar results. Conclusions: Due to complex relationships of body-mass index and blood pressure with dementia individual components cancelled each other out and rendered the sum-scores meaningless for the prediction of dementia

More Consistently Altered Connectivity Patterns for Cerebellum and Medial Temporal Lobes than for Amygdala and Striatum in Schizophrenia

Background: Brain architecture can be divided into a cortico-thalamic system and modulatory "subcortical-cerebellar" systems containing key structures such as striatum, medial temporal lobes (MTLs), amygdala, and cerebellum. Subcortical-cerebellar systems are known to be altered in schizophrenia. In particular, intrinsic functional brain connectivity (iFC) between these systems has been consistently demonstrated in patients. While altered connectivity is known for each subcortical-cerebellar system separately, it is unknown whether subcortical-cerebellar systems' connectivity patterns with the cortico-thalamic system are comparably altered across systems, i.e., if separate subcortical-cerebellar systems' connectivity patterns are consistent across patients. Methods: To investigate this question, 18 patients with schizophrenia (3 unmedicated, 15 medicated with atypical antipsychotics) and 18 healthy controls were assessed by resting-state functional magnetic resonance imaging (fMRI). Independent component analysis of fMRI data revealed cortical intrinsic brain networks (NWs) with time courses representing proxies for cortico-thalamic system activity. Subcortical-cerebellar systems' activity was represented by fMRI-based time courses of selected regions-of interest (ROls;i.e., striatum, MTL, amygdala, cerebellum). Correlation analysis among ROI- and NWs time courses yielded individual connectivity matrices [i.e., connectivity between NW and ROls (alIROls-NW, separateROI-NW), only NWs (NWs-NWs), and only ROls (alIROls-alIROls)] as main outcome measures, which were classified by support-vector-machine-based (SVM) leave-one-out cross-validation. Differences in classification accuracy were statistically evaluated for consistency across subjects and systems. Results: Correlation matrices based on aIIROls-NWs yielded 91% classification accuracy, which was significantly superior to alIROls-alIROls and NWs-NWs (56 and 74%, respectively). Considering separate subcortical-cerebellar systems, cerebellum NWs and MTL-NWs reached highest accuracy values with 91 and 85%, respectively, while those of striatum-NW and amygdala-NW were significantly lower with about 65% classification accuracy. Conclusion: Results provide initial evidence for differential consistency of altered intrinsic connectivity patterns between subcortical-cerebellar systems and the corticothalamic system. Data suggest that differential dysconnectivity patterns between subcortical-cerebellar and cortical systems might reflect different disease states or patient subgroups

Cerebrospinal Fluid BACE1 Activity and Brain Amyloid Load in Alzheimer's Disease

The secretase BACE1 is fundamentally involved in the development of cerebral amyloid pathology in Alzheimer's disease (AD). It has not been studied so far to what extent BACE1 activity in cerebrospinal fluid (CSF) mirrors in vivo amyloid load in AD. We explored associations between CSF BACE1 activity and fibrillar amyloid pathology as measured by carbon-11-labelled Pittsburgh Compound B positron emission tomography ([11C]PIB PET). [11C]PIB and CSF studies were performed in 31 patients with AD. Voxel-based linear regression analysis revealed significant associations between CSF BACE1 activity and [11C]PIB tracer uptake in the bilateral parahippocampal region, the thalamus, and the pons. Our study provides evidence for a brain region-specific correlation between CSF BACE1 activity and in-vivo fibrillar amyloid pathology in AD. Associations were found in areas close to the brain ventricles, which may have important implications for the use of BACE1 in CSF as a marker for AD pathology and for antiamyloid treatment monitoring

Therapeutic drug monitoring of rivastigmine and donepezil under consideration of CYP2D6 genotype-dependent metabolism of donepezil

Background: The efficacy of acetylcholinesterase inhibitors (AChE-I) might depend on blood concentration. While rivastigmine metabolism is independent of the cytochrome P450 system, its isoenzymes, especially CYP2D6, metabolize donepezil. CYP2D6 polymorphisms can cause altered enzyme activity resulting in lower or higher than expected drug concentrations of donepezil. Objective: We investigated correlations between clinical efficacy and serum concentrations of rivastigmine and donepezil under special consideration of CYP2D6 genotype or gene dose-dependent metabolism of donepezil. Methods: Serum concentrations of donepezil and rivastigmine were measured by liquid chromatography - tandem mass spectrometry (LC-MS/MS). Real-time quantitative polymerase chain reaction (PCR) and allele-specific PCR were performed to assess CYP2D6 genotype and gene dose. Results: Patients treated with rivastigmine (n=28) or donepezil (n=48) were included in the study. Both gene dose and metabolism type significantly predicted the level of donepezil serum concentration (p=0.019 and p=0.013, respectively). In the rivastigmine group, changes of the word list delayed recall subtest before treatment and under stable medication were significantly associated with rivastigmine serum levels (beta=0.465;p=0.018). Drug serum concentrations were outside the recommended range in a substantial percentage of participants, which might have contributed to poor correlations between changes in cognitive measures and drug concentrations. Donepezil serum concentrations significantly depended on CYP2D6 gene dose. Conclusion: Testing AChE-I serum concentration should be considered in patients without clinical response to treatment or those with severe side effects. Patients with donepezil drug levels outside the recommended range might additionally profit from CYP2D6 genotyping or treatment with an AChE-I independent of CYP metabolism