Plasma brain-derived tau is an amyloid-associated neurodegeneration biomarker in Alzheimer's disease.

Staging amyloid-beta (Aß) pathophysiology according to the intensity of neurodegeneration could identify individuals at risk for cognitive decline in Alzheimer's disease (AD). In blood, phosphorylated tau (p-tau) associates with Aß pathophysiology but an AD-type neurodegeneration biomarker has been lacking. In this multicenter study (n = 1076), we show that brain-derived tau (BD-tau) in blood increases according to concomitant Aß ("A") and neurodegeneration ("N") abnormalities (determined using cerebrospinal fluid biomarkers); We used blood-based A/N biomarkers to profile the participants in this study; individuals with blood-based p-tau+/BD-tau+ profiles had the fastest cognitive decline and atrophy rates, irrespective of the baseline cognitive status. Furthermore, BD-tau showed no or much weaker correlations with age, renal function, other comorbidities/risk factors and self-identified race/ethnicity, compared with other blood biomarkers. Here we show that blood-based BD-tau is a biomarker for identifying Aß-positive individuals at risk of short-term cognitive decline and atrophy, with implications for clinical trials and implementation of anti-Aß therapies.

Delirium is frequently underdiagnosed among older hospitalised patients despite available information in hospital medical records.

BACKGROUND: In-hospital delirium is associated with adverse outcomes and is underdiagnosed, limiting research and clinical follow-up. OBJECTIVE: To compare the incidence of in-hospital delirium determined by chart-based review of electronic medical records (D-CBR) with delirium discharge diagnoses (D-DD). Furthermore, to identify differences in symptoms, treatments and delirium triggers between D-CBR and D-DD. METHOD: The community-based cohort included 2,115 participants in the Hordaland Health Study born between 1925 and 1927. Between 2018 and 2022, we retrospectively reviewed hospital electronic medical records from baseline (1997-99) until death prior to 2023. D-DD and D-CBR were validated using The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, criteria for delirium. RESULTS: Of the 2,115 participants, 638 had in-hospital delirium. The incidence rate (IR) of D-CBR was 29.8 [95% confidence interval 28, 32] per 1,000 person-years, whereas the IR by D-DD was 3.4 [2.8, 4.2]. The IR ratio was 9.14 (P < 0.001). Patients who received pharmacological treatment for delirium (n = 121, odds ratio (OR) 3.4, [2.1, 5.4], P < 0.001), who were affected by acute memory impairment (n = 149, OR 2.8, [1.8, 4.5], P < 0.001), or change in perception (n = 137, OR 2.9, [1.8, 4.6] P < 0.001) had higher odds for D-DD. In contrast, post-operative cases (OR 0.2, [0.1, 0.4], P < 0.001) had lower odds for D-DD. CONCLUSION: Underdiagnosis of in-hospital delirium was a major issue in our study, especially in less severe delirium cases. Our findings emphasise the need for integrating systematic delirium diagnostics and documentation into hospital admission and discharge routines.

The ANeED study - ambroxol in new and early dementia with Lewy bodies (DLB): protocol for a phase IIa multicentre, randomised, double-blinded and placebo-controlled trial.

Background: Currently, there are no disease-modifying pharmacological treatment options for dementia with Lewy bodies (DLB). The hallmark of DLB is pathological alpha-synuclein (aS) deposition. There are growing amounts of data suggesting that reduced aS clearance is caused by failure in endolysosomal and authophagic pathways, as well as and glucocerebrosidase (GCase) dysfunction and mutations in the GCase gene (GBA). The population's studies demonstrated that the incidence of GBA mutations is higher among Parkinson's disease (PD) patients, and carriers of such mutations have a higher risk of developing PD. The incidence of GBA mutations is even higher in DLB and a genome-wide association study (GWAS) confirmed the correlation between GBA mutations and DLB. In vivo experiments have shown that ambroxol (ABX) may increase GCase activity and GCase levels and therefore enhance aS autophagy-lysosome degradation pathways. Moreover, there is an emerging hypothesis that ABX may have an effect as a DLB modifying drug. The aims of the study "Ambroxol in new and early Dementia with Lewy Bodies (ANeED) are to investigate the tolerability, safety and effects of ABX in patients with DLB. Methods: This is a multicentre, phase IIa, double-blinded, randomised and placebo-controlled clinical trial, using a parallel arm design for 18 months' follow-up. The allocation ratio is 1:1 (treatment:placebo). Discussion: The ANeED study is an ongoing clinical drug trial with ABX. The unique, but not fully understood mechanism of ABX on the enhancement of lysosomal aS clearance may be promising as a possible modifying treatment in DLB. Trial Registration: The clinical trial is registered in the international trials register - clinicaltrials.com (NCT0458825) and nationally at the Current Research Information System in Norway (CRISTIN 2235504).

Inflammatory Biomarkers in Newly Diagnosed Patients With Parkinson Disease and Related Neurodegenerative Disorders.

BACKGROUND AND OBJECTIVES: Neuroinflammation contributes to Parkinson disease (PD) pathology, and inflammatory biomarkers may aid in PD diagnosis. Proximity extension assay (PEA) technology is a promising method for multiplex analysis of inflammatory markers. Neuroinflammation also plays a role in related neurodegenerative diseases, such as dementia with Lewy bodies (DLB) and Alzheimer disease (AD). The aim of this work was to assess the value of inflammatory biomarkers in newly diagnosed patients with PD and in patients with DLB and AD. METHODS: Patients from the Norwegian ParkWest and Dementia Study of Western Norway longitudinal cohorts (PD, n = 120; DLB, n = 15; AD, n = 27) and 44 normal controls were included in this study. A PEA inflammation panel of 92 biomarkers was measured in the CSF. Disease-associated biomarkers were identified using elastic net (EN) analysis. We assessed the discriminatory power of disease-associated biomarkers using receiver operating characteristic (ROC) curve analysis and estimated the optimism-adjusted area under the curve (AUC) using the bootstrapping method. RESULTS: EN analysis identified 9 PEA inflammatory biomarkers (ADA, CCL23, CD5, CD8A, CDCP1, FGF-19, IL-18R1, IL-6, and MCP-2) associated with PD. Seven of the 9 biomarkers were included in a diagnostic panel, which was able to discriminate between those with PD and controls (optimism-adjusted AUC 0.82). Our 7-biomarker PD panel was also able to distinguish PD from DLB and from AD. In addition, 4 inflammatory biomarkers were associated with AD and included in a panel, which could distinguish those with AD from controls (optimism-adjusted AUC 0.87). Our 4-biomarker AD panel was also able to distinguish AD from DLB and from PD. DISCUSSION: In our exploratory study, we identified a 7-biomarker panel for PD and a 4-biomarker panel for AD. Our findings indicate potential inflammation-related biomarker candidates that could contribute toward PD-specific and AD-specific diagnostic panels, which should be further explored in other larger cohorts.

Serum Potassium Is Associated with Cognitive Decline in Patients with Lewy Body Dementia.

BACKGROUND: Epidemiological studies link serum potassium (K+) to cognitive performance, but whether cognitive prognosis in dementia is related to K+ levels is unknown. OBJECTIVE: To determine if K+ levels predict cognitive prognosis in dementia and if this varies according to diagnosis or neuropathological findings. METHODS: This longitudinal cohort study recruited 183 patients with mild Alzheimer's disease or Lewy body dementia (LBD). Serum K+ and eGFR were measured at baseline and medications which could affect K+ registered. The Mini-Mental State Examination (MMSE) was measured annually over 5 years, and mortality registered. Association between K+ and √(30 -MMSE) was estimated overall, and according to diagnosis (joint model). Associations between MMSE-decline and K+ were assessed in two subgroups with neuropathological examination (linear regression) or repeated measurements of K+ over 3 years (mixed model). RESULTS: Serum K+ at baseline was associated with more errors on MMSE over time (Estimate 0.18, p = 0.003), more so in LBD (p = 0.048). The overall association and LBD interaction were only significant in the 122 patients not using K+ relevant medication. Repeated K+ measures indicated that the association with MMSE errors over time was due to a between-person effect (p < 0.05, n = 57). The association between the annual MMSE decline was stronger in patients with autopsy confirmed LBD and more α-synuclein pathology (all: p < 0.05, n = 41). CONCLUSION: Higher serum K+ predicts poorer cognitive prognosis in demented patients not using medications which affect K+, likely a between-person effect seen mainly in LBD.

Accuracy of Clinical Diagnosis of Dementia with Lewy Bodies versus Neuropathology.

BACKGROUND: The first consensus criteria for dementia with Lewy bodies (DLB) published in 1996 were revised in 2005, partly because the original clinical criteria had suboptimal sensitivity. Few studies have assessed the accuracy of the 2005 criteria applied prospectively in newly diagnosed patients who have been followed longitudinally. OBJECTIVE: To explore the correlation between clinical and pathological diagnoses in patients with DLB and Parkinson's disease with dementia (PDD). METHODS: From a prospective referral cohort study with enriched recruitment of patients with DLB and PDD, we included the first 56 patients coming to autopsy. Patients had mild dementia at inclusion and were followed annually until death with standardized clinical assessments. Pathological assessment was performed blind to clinical information according to standardized protocols and consensus criteria for DLB. RESULTS: 20 patients received a pathological diagnosis of Lewy body disease; the corresponding clinical diagnoses were probable DLB (n = 11), PDD (n = 5), probable (n = 2) or possible (n = 2) Alzheimer's disease (AD). Of 14 patients with a clinical diagnosis of probable DLB, 11 had DLB/PDD and 3 had AD at pathology. One patient with clinically possible DLB fulfilled criteria for pathological AD. Sensitivity, specificity, positive predictive value, and negative predictive values for probable DLB were 73%, 93%, 79%, and 90%. CONCLUSION: Our findings suggest that the international clinical consensus criteria for DLB perform reasonably well. However, false positive and false negative diagnoses still occur, indicating that the criteria need to be improved, that biomarkers may be needed, and that neuropathological feedback is vital to improve accuracy.

Cognitive decline in dementia with Lewy bodies: a 5-year prospective cohort study.

OBJECTIVES: We report the cognitive decline in persons diagnosed with mild dementia with Lewy bodies (DLB) and mild Alzheimer's disease (AD) during 5 years of annual follow-ups. METHODS: Patients were recruited into the study from geriatric, psychiatric and neurology clinics in Western Norway during 2005-2013. They were diagnosed according to clinical consensus criteria, based on standardised clinical rating scales. Autopsy-based diagnoses were available for 20 cases. Cognitive decline for up to 5 years was assessed using the Clinical Dementia Rating (CDR) scale and the Mini-Mental State Examination (MMSE). Survival analysis including Cox regression (time to reach severe dementia) and linear mixed-effects (lme) modelling were used to model the decline on MMSE. RESULTS: At least one follow-up assessment was available for 67 patients with DLB and 107 patients with AD, with a median follow-up time of 4.3 years. The time to reach severe dementia was significantly shorter in DLB (median 1793 days) compared with AD (1947 days; p=0.033), and the difference remained significant in the multiple Cox regression analysis (HR=2.0, p<0.02). In the adjusted lme model, MMSE decline was faster in DLB (annual decline 4.4 points) compared with AD (3.2 points; p<0.008). CONCLUSIONS: Our findings show that from the mild dementia stage, patients with DLB have a more rapid cognitive decline than in AD. Such prognostic information is vital for patients and families and crucial for planning clinical trials and enabling health economic modelling.

Associations between Cerebrospinal Fluid Biomarkers and Cognition in Early Untreated Parkinson's Disease.

BACKGROUND: Mild cognitive impairment and dementia are common, clinically important features of Parkinson's disease (PD). The underlying disease pathology is heterogeneous and not yet well characterized. Biomarkers for cognitive impairment in PD could aid in diagnostic and prognostic evaluation and in the development of new cognitive enhancing treatments. OBJECTIVE: To examine the relationship between CSF markers and cognition in a large, multicenter, cohort study of early, untreated PD, and compare marker concentrations between PD patients with and without MCI and healthy, age-matched controls. METHODS: 414 early, untreated PD (34% with mild cognitive impairment) and 189 healthy, cognitively intact controls with baseline neuropsychological testing and CSF abeta42, t-tau, p-tau181 and α-synuclein results were included. Multiple linear regression models were constructed with a composite cognition factor, or memory-, or visuospatial- or executive-attention domains as dependent variables, and CSF markers, demographic characteristics and MDS-UPDRS III score as predictors. RESULTS: Lower α-synuclein was associated with reduced performance on the executive-attention domain and the composite cognition factor in the whole PD-group. Abeta42 was significantly decreased in PD with mild cognitive impairment compared with controls after adjusting for covariates, while values in PD without MCI were identical to healthy controls. CONCLUSIONS: The association between reduced CSF α-synuclein concentrations and cognition suggests that α-synuclein pathology contributes to early cognitive impairment in PD, in particular to executive-attentional dysfunction. Longitudinal analyses are needed to determine if this and other CSF biomarkers in early Parkinson's disease are associated with the risk of future cognitive decline and dementia.

[Biomarkers in spinal fluid of patients with dementia]. / Biomarkører i spinalvæske ved demens.

BACKGROUND: We wanted to assess whether biomarkers abeta42, tau and p-tau could differentiate between Alzheimer's disease and other dementia illnesses. MATERIAL AND METHODS: Following systematic Pubmed searches, 25 articles which reported sensitivity and specificity for Alzheimer's disease and other dementias were included. RESULTS: Most studies showed significant differences for all three markers between Alzheimer's disease and other dementia illnesses, except abeta42 which did not differ between Alzheimer's disease and dementia with Lewy bodies. Alzheimer's disease was distinguished from vascular dementia with sensitivities and specificities 77 % - 87 % and 62-80 % (abeta42); 79-100 % and 14-100 % (tau); and 78-80 % and 63-96 % (p-tau181). Alzheimer's disease and dementia with Lewy bodies were differentiated by tau and p-tau181 with sensitivities and specificities of 72-94 % and 53-92 %, and of 68-85 % and 61-85 %. Markers separated Alzheimer's disease from frontal lobe dementia with sensitivities and specificities of 37-91 % and 59-92 % (abeta42), 58-88 % and 68-92 % (tau) and 44-91 % and 79-100 % (p-tau181). INTERPRETATION: Methodological weaknesses impede the interpretation. CSF markers are not yet sufficient to differentiate between Alzheimer's disease and other forms of dementia.

Cerebrospinal Fluid Levels of sAPPα and sAPPß in Lewy Body and Alzheimer's Disease: Clinical and Neurochemical Correlates.

We measured cerebrospinal fluid (CSF) levels of the soluble isoforms of amyloid precursor protein (APP; sAPPα sAPPß) and other CSF biomarkers in 107 patients with Alzheimer's disease (AD), dementia with Lewy body dementia (DLB), Parkinson's disease dementia (PDD), and normal controls (NC) using commercial kits. DLB and PDD were combined in a Lewy body dementia group (LBD). No differences were observed in sAPPα and sAPPß levels between the groups. Significant correlations were observed between sAPPα and sAPPß and between sAPPß and Mini-Mental State Examination scores in the total group analysis as well as when LBD and AD groups were analyzed separately. sAPPα and sAPPß levels correlated with Aß38, Aß40, Aß42, and Tau in the LBD group. In AD, sAPPα correlated with p-Tau and sAPPß with Aß40. The differential association between sAPPα and sAPPß with Aß and Tau species between LBD and AD groups suggests a possible relationship with the underlying pathologies in LBD and AD.

CSF amyloid ß38 as a novel diagnostic marker for dementia with Lewy bodies.

BACKGROUND: The clinical distinction between Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) is sometimes difficult, particularly in mild cases. Although CSF markers such as amyloid ß42 (Aß42) and P-tau can distinguish between AD and normal controls, their ability to distinguish between AD and DLB is not adequate. OBJECTIVE: This study aims to investigate whether CSF markers, in particular levels of Aß38, can differentiate between mild AD and DLB. METHODS: 85 individuals were included after standardised diagnostic procedures: 30 diagnosed as probable AD, 23 probable DLB, 20 probable Parkinson's disease dementia and 12 non-demented control subjects. CSF levels of Aß38, Aß40 and Aß42 were determined using commercially available ultra-sensitive multi-array kit assay (MSD) for human Aß peptides. Total tau (T-tau) and phosphorylated tau (P-tau) were analysed using ELISA (Innotest). In addition, combinations (Aß42/Aß38, Aß42/Aß40, Aß42/P-tau and Aß42/Aß38/P-tau) were assessed. RESULTS: Significant between group differences were found for all CSF measures, and all except Aß40, Aß42 and Aß42/P-tau differed between AD and DLB. The Aß42/Aß38 ratio was the measure that best discriminated between AD and DLB (AUC 0.765; p<0.005), with a sensitivity of 78% and a specificity of 67%. CONCLUSION: This study suggests that the level of Aß38 can potentially contribute in the diagnostic distinction between AD and DLB when combined with Aß42. Single measures had low diagnostic accuracy, suggesting that developing a panel of markers is the most promising strategy. Studies with independent and larger samples and a priori cut-offs are needed to test this hypothesis.

Frequency and case identification of dementia with Lewy bodies using the revised consensus criteria.

OBJECTIVE: To find the proportion of dementia with Lewy bodies (DLB) in a referral cohort of patients with a first-time diagnosis of mild dementia. BACKGROUND: The proportion of DLB among the dementia sufferers is not known and the clinical consensus criteria have low sensitivity. We employed the revised DLB criteria to study the proportion with DLB in a community sample of patients with mild dementia. METHODS: From March 2005 to March 2007, we included 196 patients from referrals to all geriatric medicine, old age psychiatry and neurology outpatient clinics in Rogaland and Hordaland counties in Western Norway. Standardized clinical instruments and diagnostic criteria were employed. RESULTS: 65% had Alzheimer dementia, 20% DLB (16% probable DLB), 5.6% vascular dementia, 5.6% Parkinson disease with dementia, 2.0% frontotemporal dementia and 1.5% alcoholic dementia. There were no significant differences in the proportion with DLB according to age bands and dementia severity groups. The revised criteria for a clinical diagnosis of DLB increased the proportion of probable DLB by 25% compared to the previous criteria. CONCLUSION: DLB is common in patients with mild dementia, and is the second most common type of dementia. The introduction of new clinical criteria for DLB leads to an increase in the proportion diagnosed with probable DLB.

Neuropsychiatric correlates of cerebrospinal fluid biomarkers in Alzheimer's disease.

BACKGROUND: The aim of this study was to explore the relationship between cerebrospinal fluid biomarkers and neuropsychiatric symptoms in people with Alzheimer's disease. Psychosis, agitation, apathy and depression were assessed using standardised measures in 32 patients with mild Alzheimer's disease. METHODS: The levels of the 42-amino-acid form of beta-amyloid (A beta(1-42)), tau and p-tau (phosphorylated at threonine 181) were quantified using the conventional enzyme-linked immunosorbent assay method. RESULTS: Our result shows that apathy is significantly correlated with tau and p-tau but not with A beta(1-42). There were no significant correlations between indices of psychosis/agitation,or depression and cerebrospinal fluid A beta(1-42), tau or p-tau concentrations. CONCLUSION: Our finding suggests that apathy is associated with the level of neurofibrillary tangles in people with mild Alzheimer's disease. In contrast, the overall levels of neurofibrillary tangles or amyloid plaques do not seem to be associated with depression or psychosis, indicating that other brain changes contribute to these symptoms.