Assessment of immunoprecipitation with subsequent immunoassays for the blood-based diagnosis of Alzheimer's disease.

The Aß42/40 ratio and the concentration of phosphorylated Tau181 in blood plasma represent attractive biomarkers for Alzheimer's disease. As a means for reducing potential matrix effects, which may interfere with plasma immunoassays, we have previously developed a pre-analytical sample workup by semi-automated immunoprecipitation. Here we test the compatibility of pre-analytical immunoprecipitations with automated Aß1-40, Aß1-42 and phosphorylated Tau181 immunoassays on the Lumipulse platform and compare the diagnostic performance of the respective immunoprecipitation immunoassay approaches with direct plasma measurements. 71 participants were dichotomized according to their Aß42/40 ratios in cerebrospinal fluid into the diagnostic groups amyloid-positive (n = 32) and amyloid-negative (n = 39). The plasma Aß1-42/1-40 ratio and phosphorylated Tau181 levels were determined on the Lumipulse G600II platform (Fujirebio) by direct measurements in EDTA-plasma or after Aß- or Tau-immunoprecipitation, respectively. Pre-analytical immunoprecipitation of Aß turned out to be compatible with the Lumipulse Aß assays and resulted in a numerical, yet statistically not significant increase in the area under the ROC curve for plasma Aß1-42/1-40. Additionally, we observed a significant increase in the standardised effect size (Cohen's D). Pre-analytical immunoprecipitation of Tau resulted in increased differences between the diagnostic groups in terms of median and mean phosphorylated Tau 181 levels. Furthermore, we observed a greater Cohen's d (p < 0.001) and a larger area under the ROC curve (p = 0.038) after Tau-IP. Our preliminary findings in a small, preselected sample indicate that pre-analytical immunoprecipitation may have the potential to improve the diagnostic performance of plasma biomarker immunoassays for Aß1-42/1-40 and phosphorylated Tau181 to predict brain amyloid deposition.

Apathy in patients with Alzheimer's disease is a cost-driving factor.

BACKGROUND: Apathy is the most frequent neuropsychiatric symptom in patients with dementia of the Alzheimer's type (DAT). We analyzed the influence of apathy on the resource use of DAT patients and their caregivers. METHODS: Included were baseline data of 107 DAT patients from a randomized clinical trial on apathy treatment. The Resource Utilization in Dementia (RUD) instrument assessed costs over a 1-month period prior to baseline. Cost predictors were determined via a least absolute shrinkage and selection operator (LASSO). RESULTS: On average, total monthly costs were €3070, of which €2711 accounted for caregivers' and €359 for patients' costs. An increase of one point in the Apathy Evaluation Scale resulted in a 4.1% increase in total costs. DISCUSSION: Apathy is a significant cost driving factor for total costs in mild to moderate DAT. Effective treatment of apathy might be associated with reduced overall costs in DAT.

[The Cost of Early Diagnosis of Cognitive Decline in German Memory Clinics]. / Kosten der Diagnostik kognitiver Störungen in deutschen Gedächtnisambulanzen.

Dementias are expensive diseases: the net annual cost in European healthcare is about € 28.000 per case with a strong stage dependency, of which medical care accounts for about 19%. Diagnostic costs, on the other hand, account for only a small proportion of the total costs. With changes in the guidelines, biomarker tests are becoming increasingly important. At present, the concrete economic impact of biomarker-based diagnosis is largely unknown. To determine the actual costs of diagnostic procedures based on guidelines, we conducted a survey among the members of the German Memory Clinic Network (DNG). From 15 expert centres, the staff engagement time for all procedures was collected. Based on the individual engagement times of the different professions, the total of personnel costs for diagnostics was calculated using current gross personnel costs. The total sum of diagnostic costs (personnel plus procedures) was calculated for three different scenarios e. g. € 633,97 for diagnostics without biomarkers, € 1.214,90 for diagnostics with CSF biomarkers and € 4.740,58 € for diagnostics with FDG- plus Amyloid-PET. In addition, the actual diagnostic costs of the current practice in expert memory clinics were estimated, taking into account personnel costs, costs for the different procedures and the frequency of their use across all patients. This results in total average costs of € 1.394,43 per case as the mean across all centres (personnel costs € 351,72, costs for diagnostic procedures € 1.042,71). The results show that state-of-the-art diagnosis of dementia and pre-dementia states, such as mild cognitive impairment (MCI) requires financial resources, which are currently not fully reimbursed in Germany. The need for a biomarker-based etiological diagnosis of dementia and pre-dementia states will increase, due to availability of disease-modifying treatments. Therefore, the current gap of reimbursement must be filled by new models of compensation.

Evolution of psychosocial burden and psychiatric symptoms in patients with psychiatric disorders during the Covid-19 pandemic.

The Covid-19 pandemic highly impacts mental health worldwide. Patients with psychiatric disorders are a vulnerable risk population for worsening of their condition and relapse of symptoms. This study investigates the pandemic-related course of psychosocial burden in patients with pre-existing mental disorders. With the newly developed Goettingen psychosocial Burden and Symptom Inventory (Goe-BSI) psychosocial burden has been traced retrospectively (1) before the pandemic (beginning of 2020), (2) at its beginning under maximum lockdown conditions (March 2020), and (3) for the current state after maximum lockdown conditions (April/May 2020). The Goe-BSI also integrates the Adjustment Disorder New Module (ADNM-20), assesses general psychiatric symptoms, and resilience. A total of 213 patients covering all major psychiatric disorders (ICD-10 F0-F9) were interviewed once in the time range from April, 24th until May 11th, 2020. Across all diagnoses patients exhibited a distinct pattern with an initial rise followed by a decline of psychosocial burden (p < 0.001, partial η2 = 0.09; Bonferroni-corrected pairwise comparisons between all three time-points: p < 0.05 to 0.001). Female gender and high ADNM-20 scores were identified as risk factors for higher levels and an unfavorable course of psychosocial burden over time. Most psychiatric symptoms remained unchanged. Trajectories of psychosocial burden vary in parallel to local lockdown restrictions and seem to reflect an adaptive stress response. For female patients with pre-existing mental disorders and patients with high-stress responses, timely and specific treatment should be scheduled. With the continuation of the pandemic, monitoring of long-term effects is of major importance, especially when long incubation times for the development of mental health issues are considered.

Case Report: The Role of Neuropsychological Assessment and Imaging Biomarkers in the Early Diagnosis of Lewy Body Dementia in a Patient With Major Depression and Prolonged Alcohol and Benzodiazepine Dependence.

Dementia with Lewy bodies (DLB) is the second most common form of dementia and is assumed to be often under- or misdiagnosed, especially in early stages. Here we present a complex case of probable DLB with major depression and alcohol and benzodiazepine dependence in which DLB was ruled out initially. This case highlights the challenging diagnostic workup of DLB patients. Core clinical features can be missing and indicative biomarkers can be negative, especially in early stages of the disease. Initially, Fluorodeoxyglucose positron emission tomography as well as neuropsychological assessment were suspicious for a possible DLB diagnosis in our patient while core clinical criteria were missing and the indicative biomarker 123I-FP-CIT SPECT was negative. Follow up was performed two years later and the patients showed several core and supportive clinical features of DLB and 123I-FP-CIT SPECT showed a pathological pattern. Extensive neuropsychological assessment in combination with PET imaging might provide crucial evidence for DLB even in early stages. If neuropsychology and PET imaging point to an early DLB diagnosis careful follow-up should be performed as core symptoms and indicative biomarkers might appear in later stages of the disease.

Memorability of photographs in subjective cognitive decline and mild cognitive impairment: Implications for cognitive assessment.

INTRODUCTION: Impaired long-term memory is a defining feature of mild cognitive impairment (MCI). We tested whether this impairment is item specific, limited to some memoranda, whereas some remain consistently memorable. METHODS: We conducted item-based analyses of long-term visual recognition memory. Three hundred ninety-four participants (healthy controls, subjective cognitive decline [SCD], and MCI) in the multicentric DZNE-Longitudinal Cognitive Impairment and Dementia Study (DELCODE) were tested with images from a pool of 835 photographs. RESULTS: We observed consistent memorability for images in healthy controls, SCD, and MCI, predictable by a neural network trained on another healthy sample. Looking at memorability differences between groups, we identified images that could successfully categorize group membership with higher success and a substantial image reduction than the original image set. DISCUSSION: Individuals with SCD and MCI show consistent memorability for specific items, while other items show significant diagnosticity. Certain stimulus features could optimize diagnostic assessment, while others could support memory.

A two-step immunoassay for the simultaneous assessment of Aß38, Aß40 and Aß42 in human blood plasma supports the Aß42/Aß40 ratio as a promising biomarker candidate of Alzheimer's disease.

BACKGROUND: The quantification of amyloid-beta (Aß) peptides in blood plasma as potential biomarkers of Alzheimer's disease (AD) is hampered by very low Aß concentrations and the presence of matrix components that may interfere with the measurements. METHODS: We developed a two-step immunoassay for the simultaneous measurement of the relative levels of Aß38, Aß40 and Aß42 in human EDTA plasma. The assay was employed for the study of 23 patients with dementia of the Alzheimer's type (AD-D) and 17 patients with dementia due to other reasons (OD). We examined relationships with the clinical diagnosis, cerebral Aß load as quantified by amyloid-positron emission tomography, apolipoprotein E genotype, Aß levels and Tau protein in cerebrospinal fluid. RESULTS: Preconcentration of plasma Aß peptides by immunoprecipitation substantially facilitated their immunological measurements. The Aß42/Aß40 and Aß42/Aß38 ratios were statistically significantly lower in the AD-D patients than in the OD group. The areas under the receiver operating characteristic curves reached 0.87 for the Aß42/Aß40 ratio and 0.80 for the Aß42/Aß38 ratio. CONCLUSIONS: The measurement of plasma Aß peptides with an immunological assay can be improved by preconcentration via immunoprecipitation with an antibody against the Aß amino-terminus and elution of the captured peptides by heating in a mild detergent-containing buffer. Our findings support the Aß42/Aß40 ratio in blood plasma as a promising AD biomarker candidate which correlates significantly with the validated core biomarkers of AD. Further studies will be needed for technical advancement of the assay and validation of the biomarker findings.

Cardiovascular and metabolic comorbidities in patients with Alzheimer's disease and vascular dementia compared to a psychiatric control cohort.

BACKGROUND: Multimorbidity in dementia is associated with an increased risk of complications and a higher need for care. Having knowledge of cardiovascular and metabolic comorbidities is crucial when making decisions about diagnostic procedures and therapies. We compared the prevalence of comorbidities in hospitalized patients with Alzheimer's disease (AD), vascular dementia, and psychiatric diseases other than dementia. Additionally, we compared clinically relevant health-care indicators (length of hospital stay, rate of re-hospitalization) between these groups. METHODS: We used information from a database of treatment-relevant indicators from psychiatric and psychosomatic hospitals throughout Germany. This database contains routinely recorded data collected from 85 German hospitals from 2011 to 2015. In total, 14 411 AD cases, 7156 vascular dementia cases, and 34 534 cases involving non-demented psychiatric patients (used as controls) were included. To analyze comorbidities and health-care indicators, χ2 tests and t-tests were used. RESULTS: Diabetes mellitus, lipoprotein disorders, coronary artery diseases, cardiac arrhythmia and insufficiency, and atherosclerosis were significantly more prevalent in patients with vascular dementia than in those with AD and psychiatric controls. Hypertension and coronary artery diseases were less frequently associated with AD than with non-demented psychiatric controls (P < 0.001). Additionally, dementia patients with cardiovascular or metabolic diseases exhibited longer hospital stays (+ 1.4 days, P < 0.001) and were more often re-hospitalized within 3 weeks (P < 0.001) and 1 year (P < 0.001) compared to dementia patients without these comorbidities. CONCLUSIONS: Awareness of somatic comorbidities in patients with dementia is crucial to avoid complications during inpatient treatment. The occurrence of comorbid disorders was associated with longer and more frequent hospital stays, which potentially lead to higher health-care costs. Further studies should evaluate the causative association between somatic comorbidities and inpatient costs in dementia patients.

Continuity of treatment with benzodiazepines in dementia patients: an analysis of German health insurance claims data.

Long-term treatment with benzodiazepines (BZD) should be avoided in dementia patients because of an increased risk of adverse events. We evaluated how continuously dementia patients were prescribed BZD over 12 months. For this observational study, we used claims data from a large German public sickness fund for 2014 and 2015, including patients with an incident diagnosis of dementia in 2014. The aim was to evaluate the continuity of treatment, the frequency of BZD prescriptions and defined daily doses were evaluated. In total, 1298 (5.6%) patients received 4.7±5.2 BZD prescriptions in 2015 on average. Thereof, lorazepam (47.5%), oxazepam (18.6%), diazepam (14.5%), and bromazepam (12.2%) were most often prescribed. 30.7% of the patients received at least one BZD prescription in each quarter of 2015. Although the total number of patients receiving BZD decreased in 2015, defined daily doses for single substances remained mainly unchanged. The incident diagnosis of dementia was not associated with modifications of prescription behavior. The treatment with BZD was not discontinued in a large proportion of dementia patients, increasing the risk of adverse events. Physicians' awareness of avoiding BZD should be improved and further evidence for the appropriate treatment of psychiatric symptoms in dementia (e.g. sleep disturbances, anxiety) is required.

Direct analytical sample quality assessment for biomarker investigation: qualifying cerebrospinal fluid samples.

Measurement of biochemical markers represents an important aid to clinicians in the early diagnosis and prognosis of neurological diseases. Many factors can contribute to increase the chances that a biomarker study becomes successful. In a cerebrospinal fluid analysis (CSF), more than 84% of laboratory errors can be attributed to several preanalytical variables that include CSF collection, storage, and freeze thawing cycles. In this concept paper, we focus on some critical issues arising from basic proteomics investigation in order to highlight some key elements of CSF quality control. Furthermore, we propose a direct assessment of sample quality (DASQ) by applying a fast MALDI-TOF-MS methodology to evaluate molecular features of sample degradation and oxidation. We propose DASQ as a fast and simple initial step to be included in large-scale projects for neurological biomarker studies. In fact, such a procedure will improved the development of standardized protocols in order to have well-characterized CSF biobanks.

Quantification of the electroencephalographic theta/alpha ratio for the assessment of portal-systemic encephalopathy following implantation of transjugular intrahepatic portosystemic stent shunt (TIPSS).

The aim of the study was the quantification of metabolically caused electroencephalographic changes of portal-systemic encephalopathy, a prototype of hepatic encephalopathy. We examined 12 patients with liver cirrhosis before and after implantation of a transjugular intrahepatic portosystemic stent shunt (TIPSS) by means of quantitative digital electroencephalography (EEG). One month after TIPSS implantation, all patients showed an increase in the power of the theta frequency band as well as a decrease in the power of the alpha frequency band. To reduce the error variance, we formed the quotient of the relative power of the theta and alpha frequency band. Theta/alpha quotient values over 0.7 indicate a general change of the EEG with a sensitivity of 93% and a specificity of 87%. The results we have to hand indicate a correlation between the albumin concentration and the theta/alpha quotient 1 and 3 months after TIPSS. No significant correlation was revealed with regard to the Child-Pugh score or the liver function parameters cholinesterase, bilirubin, and prothrombin time. Neither the arterial ammonia concentration nor the performance in the psychometric test showed significance in relation to the theta/alpha quotient. Substances with a high albumin bond and potential neurotoxicity may--in the case of lower albumin levels--be absorbed with increased frequency in the CNS and may be responsible for the observed EEG change.