Microglial responses partially mediate the effect of Aß on cognition in Alzheimer's disease.

INTRODUCTION: Microglial responses are an integral part of Alzheimer's disease (AD) pathology and are associated with amyloid beta (Aß) deposition. This study aimed to investigate the effects of Aß and microglial responses on global cognitive impairment. METHODS: In this longitudinal study, 28 patients with mild cognitive impairment and 11 healthy controls underwent 11C-PK11195 and 11C-Pittsburgh compound B positron emission tomography (PET), structural magnetic resonance imaging scans, and global cognitive ratings at baseline and 2-year follow-up. Correlations between PET uptake and global cognition were assessed. Additionally, the mediation effect of the microglial response on the association between Aß load and global cognition was assessed. RESULTS: Aß load and the microglial response were both independently detrimental to global cognitive performance at baseline; however, at 2-year follow-up the association between Aß load and global cognitive ratings was partially mediated by the microglial response. DISCUSSION: As AD progresses, the associated microglial response partially mediates the detrimental effect of aggregated Aß on cognition. HIGHLIGHTS: This was a longitudinal study of amyloid beta (Aß), microglial responses, and global cognitive performance. Aß and microglial responses both affect cognition in early Alzheimer's disease. Microglial response partially mediates the effect of Aß on cognition in later stages.

Correlation between dopaminergic and metabolic asymmetry in Lewy body disease - A dual-imaging study.

INTRODUCTION: The a-Synuclein Origin and Connectome (SOC) model of Lewy body diseases postulates that a-syuclein will be asymmetrically distributed in some patients with Lewy body diseases, potentially leading to asymmetric neuronal dysfunction and symptoms. METHODS: We included two patient groups: 19 non-demented Parkinson's disease (nPD) patients with [18F]FDG PET and motor symptoms assessed by UPDRS-III, and 65 Lewy body dementia (LBD) patients with [18F]FDG PET and dopamine radioisotope imaging. Asymmetry indices were calculated for [18F]FDG PET by including the cortex for each hemisphere, for dopamine radioisotope imaging by including the putamen and caudate separately, and for motor symptoms by using the difference between right-left UPDRS-III score. Correlations between these asymmetry indices were explored to test the predictions of the SOC model. To identify cases with a more typical LBD imaging profile, we calculated a Cingulate Island Sign (CIS) index on the [18F]FDG PET image. RESULTS: We found a significant correlation between cortical interhemispheric [18F]FDG asymmetry and motor-symptom asymmetry in nPD patients (r = 0.62, P = 0.004). In patients with LBD, we found a significant correlation between cortical interhemispheric [18F]FDG asymmetry and dopamine transporter asymmetry in the caudate (r = 0.37, P = 0.0019), but not in the putamen (r = 0.15, P = 0.22). We observed that the correlation in the caudate was stronger in LBD subjects with the highest CIS index, i.e., with more typical LBD imaging profiles. CONCLUSION: Our study partly supports the SOC model, but further investigations are needed - ideally of de novo, non-demented PD patients.

Prescription medication use in the 10 years prior to diagnosis of young onset Alzheimer's disease: a nationwide nested case-control study.

BACKGROUND: Patients with young onset Alzheimer's disease (YOAD) face long diagnostic delays. Prescription medication use may provide insights into early signs and symptoms, which may help facilitate timely diagnosis. METHODS: In a register-based nested case-control study, we examined medication use for everyone diagnosed with YOAD in a Danish memory clinic during 2016-2020 compared to cognitively healthy controls. Prescription medication use were grouped into 13 overall categories (alimentary tract and metabolism, blood and blood forming organs, cardiovascular system, dermatologicals, genitourinary system and sex hormones, systemic hormonal preparations, antiinfectives for systemic use, antineoplastic and immunomodulating agents, musculo-skeletal system, nervous system, antiparasitic products, respiratory system, and sensory organs). Further stratifications were done for predetermined subcategories with a use-prevalence of at least 5% in the study population. Conditional logistic regression produced odds ratios, which given the use of incidence-density matching is interpretable as incidence rate ratios (IRRs). The association between prescription medication use and subsequent YOAD diagnosis was examined in the entire 10-year study period and in three time-intervals. RESULTS: The study included 1745 YOAD cases and 5235 controls. In the main analysis, several overall categories showed significant associations with YOAD in one or more time-intervals, namely blood and blood forming organs and nervous system. Prescription medication use in the nervous system category was increased for YOAD cases compared to controls already 10->5 years prior to diagnosis (IRR 1.17, 95% CI 1.05-1.31), increasing to 1.57 (95% CI 1.39-1.78) in the year preceding diagnosis. This was largely driven by antidepressant and antipsychotic use, and especially prominent for first-time users. CONCLUSIONS: In this study, medication use in several categories was associated with YOAD. Onset of treatment-requiring psychiatric symptoms such as depression or psychosis in mid-life may serve as potential early indicators of YOAD.

Mapping morbidity 10 years prior to a diagnosis of young onset Alzheimer's disease.

INTRODUCTION: Early symptoms in young onset Alzheimer's disease (YOAD) may be misinterpreted, causing delayed diagnosis. This population-based study aimed to map morbidity prior to YOAD diagnosis. METHODS: In a register-based incidence density matched nested case-control study, we examined hospital-diagnosed morbidity for people diagnosed with YOAD in Danish memory clinics during 2016-2020 compared to controls in a 10-year period. Conditional logistic regression produced incidence rate ratios (IRRs). RESULTS: The study included 1745 cases and 5235 controls. YOAD patients had a higher morbidity burden in the year immediately before dementia diagnosis, for certain disorders up to 10 years before. This was especially evident for psychiatric morbidity with the highest increased IRRs throughout the entire period and IRR 1.43 (95% confidence interval 1.14-1.79) in the 5-10-years before dementia diagnosis. DISCUSSION: YOAD patients display a different pattern of morbidity up to 10 years prior to diagnosis. Awareness of specific alterations in morbidity may improve efforts toward a timely diagnosis. HIGHLIGHTS: Retrospective, nested case-control study of young onset Alzheimer's disease (YOAD). YOAD cases had a higher morbidity burden than controls. YOAD cases had a higher psychiatric morbidity burden up to 10 years before diagnosis. Altered morbidity patterns could serve as an early warning sign of YOAD.

Impaired cholinergic integrity of the colon and pancreas in dementia with Lewy bodies.

Dementia with Lewy bodies is characterized by a high burden of autonomic dysfunction and Lewy pathology in peripheral organs and components of the sympathetic and parasympathetic nervous system. Parasympathetic terminals may be quantified with 18F-fluoroetoxybenzovesamicol, a PET tracer that binds to the vesicular acetylcholine transporter in cholinergic presynaptic terminals. Parasympathetic imaging may be useful for diagnostics, improving our understanding of autonomic dysfunction and for clarifying the spatiotemporal relationship of neuronal degeneration in prodromal disease. Therefore, we aimed to investigate the cholinergic parasympathetic integrity in peripheral organs and central autonomic regions of subjects with dementia with Lewy bodies and its association with subjective and objective measures of autonomic dysfunction. We hypothesized that organs with known parasympathetic innervation, especially the pancreas and colon, would have impaired cholinergic integrity. To achieve these aims, we conducted a cross-sectional comparison study including 23 newly diagnosed non-diabetic subjects with dementia with Lewy bodies (74 ± 6 years, 83% male) and 21 elderly control subjects (74 ± 6 years, 67% male). We obtained whole-body images to quantify PET uptake in peripheral organs and brain images to quantify PET uptake in regions of the brainstem and hypothalamus. Autonomic dysfunction was assessed with questionnaires and measurements of orthostatic blood pressure. Subjects with dementia with Lewy bodies displayed reduced cholinergic tracer uptake in the pancreas (32% reduction, P = 0.0003) and colon (19% reduction, P = 0.0048), but not in organs with little or no parasympathetic innervation. Tracer uptake in a region of the medulla oblongata overlapping the dorsal motor nucleus of the vagus correlated with autonomic symptoms (rs = -0.54, P = 0.0077) and changes in orthostatic blood pressure (rs = 0.76, P < 0.0001). Tracer uptake in the pedunculopontine region correlated with autonomic symptoms (rs = -0.52, P = 0.0104) and a measure of non-motor symptoms (rs = -0.47, P = 0.0230). In conclusion, our findings provide the first imaging-based evidence of impaired cholinergic integrity of the pancreas and colon in dementia with Lewy bodies. The observed changes may reflect parasympathetic denervation, implying that this process is initiated well before the point of diagnosis. The findings also support that cholinergic denervation in the brainstem contributes to dysautonomia.

Placebo analgesia and nocebo hyperalgesia in patients with Alzheimer disease and healthy participants.

ABSTRACT: The role of placebo analgesia and nocebo hyperalgesia in patients with Alzheimer disease (AD) is largely unknown, with only few studies in the area. Therefore, this study aims to investigate to which extent placebo analgesia and nocebo hyperalgesia effects are present in patients experiencing mild-to-moderate AD. Twenty-one patients with AD (test population) and 26 healthy participants (HP; design validation) were exposed to thermal pain stimulation on 3 test days: Lidocaine condition (open/hidden lidocaine administration), capsaicin condition (open/hidden capsaicin administration), and natural history (no treatment), in a randomized, within-subject design. Open lidocaine and open capsaicin were accompanied by verbal suggestions for pain relief and pain increase, respectively. Expected pain and actual pain intensity were measured on a numerical rating scale (0-10). Placebo and nocebo effects were calculated as pain differences in open-hidden lidocaine and capsaicin, respectively, controlled for no treatment. Healthy participants obtained a placebo effect ( P = 0.01) and a trend for a nocebo effect ( P = 0.07). Patients with AD did not obtain a placebo effect ( P = 0.44) nor a significant nocebo effect ( P = 0.86). Healthy participants expected lower and higher pain with open vs hidden lidocaine and capsaicin, respectively ( P < 0.001). The same expectation effects were seen in patients with AD (open vs hidden lidocaine, P = 0.008; open vs hidden capsaicin, P < 0.001). With a well-controlled experimental setting, this study suggests that patients with AD may not experience placebo analgesia effects. Nocebo hyperalgesia effects in patients with AD needs further research. These findings may have implications for the conduction of clinical trials and the treatment of patients with AD in clinical practice.

Intravenous thrombolysis for acute ischemic stroke is associated with lower risk of post-stroke dementia: A nationwide cohort study.

INTRODUCTION: Dementia after stroke is common and is a great concern for patients and their caregivers. The objective was to investigate if intravenous thrombolysis (IVT) for acute ischemic stroke (AIS) was associated with lower risk of dementia after stroke. PATIENTS AND METHODS: When IVT was introduced in Denmark, not all eligible patients were treated due to restricted access. We conducted a nationwide register-based cohort study of all patients with AIS in Denmark from 2004 to 2011. IVT-treated patients were propensity score-matched with comparable non-treated patients. Cox proportional hazards regression was used to estimate the hazard ratio (HR) for all-cause and vascular dementia 2, 5, and 10 years after stroke. RESULTS: Of the 5919 patients eligible for the study, 2305 IVT-treated patients were propensity score-matched with 2305 non-treated patients. Mean (SD) age was 66.6 (13.3) and 61.2% were male. Rate of all-cause dementia was lower for the IVT-treated 2 years (8.4/1000 person years (PY) vs 13.6/1000 PY, HR 0.63 (0.40-0.99)) and 5 years after stroke (7.3/1000 PY vs 11.4/1000 PY, HR 0.65 (0.46-0.91)). 10 years after stroke, the rates of all-cause dementia remained in favor of IVT (8.0/1000 PY vs 9.8/1000 PY, HR 0.83 (0.64-1.07)). IVT-treated had lower rates of vascular dementia 2 years (2.4/1000 PY vs 7.4/1000 PY, HR 0.33 (0.15-0.71)), 5 years (2.3/1000 PY vs 6.2/1000 PY, HR 0.38 (0.23-0.65)), and 10 years after stroke (3.0/1000 PY vs 5.4/1000 PY, HR 0.56 (0.38-0.81)). CONCLUSION: IVT treatment was associated with lower long-term risk of both vascular and all-cause dementia after AIS.

Neuron-derived extracellular vesicles in blood reveal effects of exercise in Alzheimer's disease.

BACKGROUND: Neuron-derived extracellular vesicles (NDEVs) in blood may be used to derive biomarkers for the effects of exercise in Alzheimer's disease (AD). For this purpose, we studied changes in neuroprotective proteins proBDNF, BDNF, and humanin in plasma NDEVs from patients with mild to moderate AD participating in the randomized controlled trial (RCT) of exercise ADEX. METHODS: proBDNF, BDNF, and humanin were quantified in NDEVs immunocaptured from the plasma of 95 ADEX participants, randomized into exercise and control groups, and collected at baseline and 16 weeks. Exploratorily, we also quantified NDEV levels of putative exerkines known to respond to exercise in peripheral tissues. RESULTS: NDEV levels of proBDNF, BDNF, and humanin increased in the exercise group, especially in APOE ε4 carriers, but remained unchanged in the control group. Inter-correlations between NDEV biomarkers observed at baseline were maintained after exercise. NDEV levels of putative exerkines remained unchanged. CONCLUSIONS: Findings suggest that the cognitive benefits of exercise could be mediated by the upregulation of neuroprotective factors in NDEVs. Additionally, our results indicate that AD subjects carrying APOE ε4 are more responsive to the neuroprotective effects of physical activity. Unchanged NDEV levels of putative exerkines after physical activity imply that exercise engages different pathways in neurons and peripheral tissues. Future studies should aim to expand upon the effects of exercise duration, intensity, and type in NDEVs from patients with early AD and additional neurodegenerative disorders. TRIAL REGISTRATION: The Effect of Physical Exercise in Alzheimer Patients (ADEX) was registered in ClinicalTrials.gov on April 30, 2012 with the identifier NCT01681602.

Severe cholinergic terminal loss in newly diagnosed dementia with Lewy bodies.

Cholinergic changes play a fundamental role in the natural history of dementia with Lewy bodies and Lewy body disease in general. Despite important achievements in the field of cholinergic research, significant challenges remain. We conducted a study with four main objectives: (i) to examine the integrity of cholinergic terminals in newly diagnosed dementia with Lewy bodies; (ii) to disentangle the cholinergic contribution to dementia by comparing cholinergic changes in Lewy body patients with and without dementia; (iii) to investigate the in vivo relationship between cholinergic terminal loss and atrophy of cholinergic cell clusters in the basal forebrain at different stages of Lewy body disease; and (iv) to test whether any asymmetrical degeneration in cholinergic terminals would correlate with motor dysfunction and hypometabolism. To achieve these objectives, we conducted a comparative cross-sectional study of 25 newly diagnosed dementia with Lewy bodies patients (age 74 ± 5 years, 84% male), 15 healthy control subjects (age 75 ± 6 years, 67% male) and 15 Parkinson's disease patients without dementia (age 70 ± 7 years, 60% male). All participants underwent 18F-fluoroetoxybenzovesamicol PET and high-resolution structural MRI. In addition, we collected clinical 18F-fluorodeoxyglucose PET images. Brain images were normalized to standard space and regional tracer uptake and volumetric indices of basal forebrain degeneration were extracted. Patients with dementia showed spatially distinct reductions in cholinergic terminals across the cerebral cortex, limbic system, thalamus and brainstem. Also, cholinergic terminal binding in cortical and limbic regions correlated quantitatively and spatially with atrophy of the basal forebrain. In contrast, patients without dementia showed decreased cholinergic terminal binding in the cerebral cortex despite preserved basal forebrain volumes. In patients with dementia, cholinergic terminal reductions were most severe in limbic regions and least severe in occipital regions compared to those without dementia. Interhemispheric asymmetry of cholinergic terminals correlated with asymmetry of brain metabolism and lateralized motor function. In conclusion, this study provides robust evidence for severe cholinergic terminal loss in newly diagnosed dementia with Lewy bodies, which correlates with structural imaging measures of cholinergic basal forebrain degeneration. In patients without dementia, our findings suggest that loss of cholinergic terminal function occurs 'before' neuronal cell degeneration. Moreover, the study supports that degeneration of the cholinergic system is important for brain metabolism and may be linked with degeneration in other transmitter systems. Our findings have implications for understanding how cholinergic system pathology contributes to the clinical features of Lewy body disease, changes in brain metabolism and disease progression patterns.

Dopaminergic Dysfunction Is More Symmetric in Dementia with Lewy Bodies Compared to Parkinson's Disease.

BACKGROUND: The α-syn Origin site and Connectome model (SOC) proposes that α-synucleinopathies can be divided into two categories: the asymmetrical brain-first, and more symmetrical body-first Lewy body disease. We have hypothesized that most patients with dementia with Lewy bodies (DLB) belong to the body-first subtype, whereas patients with Parkinson's disease (PD) more often belong to the brain-first subtype. OBJECTIVE: To compare asymmetry of striatal dopaminergic dysfunction in DLB and PD patients using [18F]-FE-PE2I positron emission tomography (PET). METHODS: We analyzed [18F]-FE-PE2I PET data from 29 DLB patients and 76 PD patients who were identified retrospectively during a 5-year period at Dept. of Neurology, Aarhus University Hospital. Additionally, imaging data from 34 healthy controls was used for age-correction and visual comparison. RESULTS: PD patients showed significantly more asymmetry in specific binding ratios between the most and least affected putamen (p < 0.0001) and caudate (p = 0.003) compared to DLB patients. PD patients also had more severe degeneration in the putamen compared to the caudate in comparison to DLB patients (p < 0.0001) who had a more universal pattern of striatal degeneration. CONCLUSION: Patients with DLB show significantly more symmetric striatal degeneration on average compared to PD patients. These results support the hypothesis that DLB patients may be more likely to conform to the body-first subtype characterized by a symmetrical spread of pathology, whereas PD patients may be more likely to conform to the brain-first subtype with more lateralized initial propagation of pathology.

Synaptic Density and Glucose Consumption in Patients with Lewy Body Diseases: An [11 C]UCB-J and [18 F]FDG PET Study.

BACKGROUND: Patients with Lewy body diseases exhibit variable degrees of cortical and subcortical hypometabolism. However, the underlying causes behind this progressive hypometabolism remain unresolved. Generalized synaptic degeneration may be one key contributor. OBJECTIVE: The objective of this study was to investigate whether local cortical synaptic loss is proportionally linked to the magnitude of hypometabolism in Lewy body disease. METHOD: Using in vivo positron emission tomography (PET) we investigated cerebral glucose metabolism and quantified the density of cerebral synapses, as measured with [18 F]fluorodeoxyglucose ([18 F]FDG) PET and [11 C]UCB-J, respectively. Volumes-of-interest were defined on magnetic resonance T1 scans and regional standard uptake value ratios-1 values were obtained for 14 pre-selected brain regions. Between-group comparisons were conducted at voxel-level. RESULTS: We observed regional differences in both synaptic density and cerebral glucose consumption in our cohorts of non-demented and demented patients with Parkinson's disease or dementia with Lewy bodies compared to healthy subjects. Additionally, voxel-wise comparisons showed a clear difference in cortical regions between demented patients and controls for both tracers. Importantly, our findings strongly suggested that the magnitude of reduced glucose uptake exceeded the magnitude of reduced cortical synaptic density. CONCLUSION: Here, we investigated the relationship between in vivo glucose uptake and the magnitude of synaptic density as measured using [18 F]FDG PET and [11 C]UCB-J PET in Lewy body patients. The magnitude of reduced [18 F]FDG uptake was greater than the corresponding decline in [11 C]UCB-J binding. Therefore, the progressive hypometabolism seen in Lewy body disorders cannot be fully explained by generalized synaptic degeneration. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Aerobic exercise does not affect serum neurofilament light in patients with mild Alzheimer's disease.

Introduction: Aerobic exercise has been shown to modify Alzheimer pathology in animal models, and in patients with multiple sclerosis to reduce neurofilament light (NfL), a biomarker of neurodegeneration. Objective: To investigate whether a 16-week aerobic exercise program was able to reduce serum NfL in patients with mild Alzheimer's disease (AD). Methods: This is a secondary analysis of data from the multi-center Preserving Cognition, Quality of Life, Physical Health, and Functional Ability in Alzheimer's disease: The Effect of Physical Exercise (ADEX) study. Participants were randomized to 16 weeks of moderate intensity aerobic exercise or usual care. Clinical assessment and measurement of serum NfL was done at baseline and after the intervention. Results: A total of 136 participants were included in the analysis. Groups were comparable at baseline except for APOEε4 carriership which was higher in the usual care group (75.3 versus 60.2%; p = 0.04). There was no effect of the intervention on serum NfL [intervention: baseline NfL (pg/mL) 25.76, change from baseline 0.87; usual care: baseline 27.09, change from baseline -1.16, p = 0.09]. Conclusion: The findings do not support an effect of the exercise intervention on a single measure of neurodegeneration in AD. Further studies are needed using other types and durations of exercise and other measures of neurodegeneration. Clinical trial registration: clinicaltrials.gov, identifier NCT01681602.

Distribution of cholinergic nerve terminals in the aged human brain measured with [18F]FEOBV PET and its correlation with histological data.

INTRODUCTION: [18F]fluoroetoxybenzovesamicol ([18F]FEOBV) is a positron emission topography (PET) tracer for the vesicular acetylcholine transporter (VAChT), a protein located predominantly in synaptic vesicles in cholinergic nerve terminals. We aimed to use [18F]FEOBV PET to study the cholinergic topography of the healthy human brain. MATERIALS AND METHODS: [18F]FEOBV PET brain data volumes of healthy elderly humans were normalized to standard space and intensity-normalized to the white matter. Stereotactic atlases of regions of interest were superimposed to describe and quantify tracer distribution. The spatial distribution of [18F]FEOBV PET uptake was compared with histological and gene expression data. RESULTS: Twenty participants of both sexes and a mean age of 73.9 ± 6.0 years, age-range [64; 86], were recruited. Highest tracer binding was present in the striatum, some thalamic nuclei, and the basal forebrain. Intermediate binding was found in most nuclei of the brainstem, thalamus, and hypothalamus; the vermis and flocculonodular lobe; and the hippocampus, amygdala, insula, cingulate, olfactory cortex, and Heschl's gyrus. Lowest binding was present in most areas of the cerebral cortex, and in the cerebellar nuclei and hemispheres. The spatial distribution of tracer correlated with immunohistochemical post-mortem data, as well as with regional expression levels of SLC18A3, the VAChT coding gene. DISCUSSION: Our in vivo findings confirm the regional cholinergic distribution in specific brain structures as described post-mortem. A positive spatial correlation between tracer distribution and regional gene expression levels further corroborates [18F]FEOBV PET as a validated tool for in vivo cholinergic imaging. The study represents an advancement in the continued efforts to delineate the spatial topography of the human cholinergic system in vivo.

Capillary dysfunction correlates with cortical amyloid load in early Alzheimer's disease.

Alterations in cerebral perfusion is increasingly considered to play a crucial role in Alzheimer's disease (AD) and together with accumulated amyloid-ß, deficiencies in the brain microvascular circulation may result in local hypoxia. Here, we studied alterations in cerebral circulation and the correlation between amyloid-ß load and cerebral perfusion in prodromal AD (pAD). Using dynamic susceptibility contrast MRI and PET, we evaluated cerebral perfusion and amyloid-ß levels in 19 individuals with mild cognitive impairment (MCI) and high amyloid-ß load (pAD-MCI), 13 MCI individuals without AD pathology and 21 healthy controls. The pAD-MCI group showed significantly lower microvascular blood flow and significantly higher heterogeneity of microvascular blood transit times (p < 0.01) compared with the other 2 groups. Additionally, in the pAD-MCI group raised amyloid-ß levels correlated with decreased microvascular blood flow and increased heterogeneity of microvascular blood flow in frontal and temporal areas (p < 0.01). These results indicate a close connection between levels of amyloid-ß deposition and brain microvascular perfusion in pAD. A vicious cycle may be established where amyloid-ß load and deficiencies in brain perfusion may reinforce each other.

Validity of the Brief Assessment of Impaired Cognition case-finding instrument for identification of dementia subgroups and staging of dementia.

BACKGROUND AND PURPOSE: The aims of this study were to examine the psychometric properties of the Brief Assessment of Impaired Cognition (BASIC) case-finding instrument in clinical settings focusing on (i) test-retest reliability, (ii) the discriminative validity of BASIC and its components for identification of Alzheimer disease (AD) dementia and non-AD dementia, and (iii) the association of expert clinical rating of cognitive status with BASIC performance. METHODS: The test-retest reliability analysis was based on a sample of general practice patients (n = 59) retested with a mean interval of 19 days. Discriminative validity analyses and analysis of the association of cognitive status with BASIC performance were based on data from the primary validation study of BASIC in memory clinics. RESULTS: The test-retest reliability of BASIC was high (r = 0.861). No significant difference in discriminative validity was found for identification of AD dementia (sensitivity = 0.99, specificity = 0.98) and non-AD dementia (sensitivity = 0.90, specificity = 0.98). All components of BASIC contributed to the high discriminative validity of both AD and non-AD dementia. BASIC performance was significantly correlated with expert clinical rating of the cognitive status of patients. A crude staging model for cognitive status using BASIC score intervals had superior classification accuracy (70%) compared to a Mini-Mental State Examination (MMSE) score range-based model (58% accuracy). CONCLUSIONS: BASIC is a reliable and valid case-finding instrument for AD dementia and non-AD dementia in clinical settings. BASIC performance is significantly associated with the degree of cognitive impairment, and BASIC seems to be superior to MMSE for staging of impairment.

Diagnostic Cut-offs for CSF ß-amyloid and tau proteins in a Danish dementia clinic.

BACKGROUND: Analysis of beta-amyloid 1-42 (Aß42), total tau (t-tau) and phosphorylated-tau 181 (p-tau) in the cerebrospinal fluid (CSF) is often performed as a part of the diagnostic work-up in case of suspected Alzheimer's dementia (AD). Unfortunately, studies on optimal CSF biomarker cut-offs in a real-world clinical setting are scarce. METHODS: We retrospectively evaluated the biomarker levels of 264 consecutive patients referred to our dementia clinic. The biomarkers were analysed with the Elecsys(R) assays. Diagnoses were based on all available clinical information, including FDG-PET scans. RESULTS: In total, we identified 233 patients diagnosed with dementia. The median MMSE score was 22 (IQR 18-25). AD pathophysiology was suspected in 156 patients, and the corresponding cut-offs based on the Youden index were: Aß42: 903 ng/L (ROC-AUC 0.78); t-tau: 272 ng/L (ROC-AUC 0.78); p-tau: 24 ng/L (ROC-AUC 0.85); t-tau/Aß42 ratio: 0.34 (ROC-AUC 0.91); p-tau/Aß42 ratio: 0.029 (ROC-AUC 0.92). CONCLUSIONS: We found the tau/Aß42 ratios to possess the best diagnostic performance, but our estimated cut-off values for the ratios were somewhat higher than previously reported. Consequently, if the CSF analyses are used to support a diagnosis of AD in a heterogeneous high-prevalence cohort, adjustment of the cut-offs may be warranted.

Capillary function progressively deteriorates in prodromal Alzheimer's disease: A longitudinal MRI perfusion study.

Cardiovascular risk factors are associated with the development of Alzheimer's disease (AD), and increasing evidence suggests that cerebral microvascular dysfunction plays a vital role in the disease progression. Using magnetic resonance imaging, we investigated the two-year changes of the cerebral microvascular blood flow in 11 mild cognitively impaired (MCI) patients with prodromal AD compared to 12 MCI patients without evidence of AD and 10 cognitively intact age-matched controls. The pAD-MCI patients displayed widespread deterioration in microvascular cerebral perfusion associated with capillary dysfunction. No such changes were observed in the other two groups, suggesting that the dysfunction in capillary perfusion is linked to the AD pathophysiology. The observed capillary dysfunction may limit local oxygenation in AD leading to downstream ß-amyloid aggregation, tau hyperphosphorylation, neuroinflammation and neuronal dysfunction. The findings are in agreement with the capillary dysfunction hypothesis of AD, suggesting that increasing heterogeneity of capillary blood flow is a primary pathological event in AD.

Observing Pain in Individuals with Cognitive Impairment: A Pilot Comparison Attempt across Countries and across Different Types of Cognitive Impairment.

Facial expression is a key aspect in observational scales developed to improve pain assessment in individuals with cognitive impairments. Although these scales are used internationally in individuals with different types of cognitive impairments, it is not known whether observing facial expressions of pain might differ between regions or between different types of cognitive impairments. In a pilot study, facial responses to standardized experimental pressure pain were assessed among individuals with different types of cognitive impairments (dementia, mild cognitive impairment, Huntington's disease, and intellectual disability) from different countries (Denmark, Germany, Italy, Israel, and Spain) and were analyzed using facial descriptors from the PAIC scale (Pain Assessment in Impaired Cognition). We found high inter-rater reliability between observers from different countries. Moreover, facial responses to pain did not differ between individuals with dementia from different countries (Denmark, Germany, and Spain). However, the type of cognitive impairment had a significant impact; with individuals with intellectual disability (all being from Israel) showing the strongest facial responses. Our pilot data suggest that the country of origin does not strongly affect how pain is facially expressed or how facial responses are being scored. However, the type of cognitive impairment showed a clear effect in our pilot study, with elevated facial responses in individuals with intellectual disability.

Does Certainty of Genuine Treatment Increase the Drug Response in Alzheimer's Disease Patients: A Meta-Analysis and Critical Discussion.

BACKGROUND: Non-specific treatment effects, such as expectations, contribute to the effectiveness of pharmacological treatments across diseases. However, the contribution of expectancy, i.e., certainty of receiving treatment, in patients with Alzheimer's disease (AD) is unknown. OBJECTIVE: The aim is to investigate whether certainty of receiving a genuine treatment influences the response to active treatment in AD patients. METHODS: The efficacy of active treatments in open-label trials, where patients are certain of receiving treatment (100%certainty), was compared to the same active treatments in randomized controlled trials (RCT), where patients are uncertain of receiving treatment or placebo (50%certainty). RESULTS: In the seven open-label trials, there was no significant difference between post- and pre-treatment scores (difference in means = 0.14, 95%CI [-0.51; 0.81], p = 0.66). In the eight RCT trials, there was a significant difference between post- and pre-treatment (difference in means = -0.91, 95%CI [-1.43; -0.41], p < 0.001). There was a statistically significant difference between open-label and RCT trials (difference = 1.06, 95%CI [0.23; 1.90], p = 0.001). CONCLUSION: Patients with AD did not benefit from certainty of receiving genuine treatment. This could be due to the nature/progression of the disease, but it could also be related to an order effect in the practice of running AD trials, where RCTs are conducted prior to open label. These findings have implications for the understanding of non-specific treatment effects in AD patients as well as for the design of clinical trials that test pharmacological treatments in AD.