| 1. |
- Aguillon, David, et al.
(författare)
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Plasma p-tau217 predicts in vivo brain pathology and cognition in autosomal dominant Alzheimer's disease
- 2023
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 19:6, s. 2585-2594
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Plasma-measured tau phosphorylated at threonine 217 (p-tau217) is a potential non-invasive biomarker of Alzheimer's disease (AD). We investigated whether plasma p-tau217 predicts subsequent cognition and positron emission tomography (PET) markers of pathology in autosomal dominant AD. Methods: We analyzed baseline levels of plasma p-tau217 and its associations with amyloid PET, tau PET, and word list delayed recall measured 7.61 years later in non-demented age- and education-matched presenilin-1 E280A carriers (n = 24) and non-carrier (n = 20) family members. Results: Carriers had higher plasma p-tau217 levels than non-carriers. Baseline plasma p-tau217 was associated with subsequent amyloid and tau PET pathology levels and cognitive function. Discussion: Our findings suggest that plasma p-tau217 predicts subsequent brain pathological burden and memory performance in presenilin-1 E280A carriers. These results provide support for plasma p-tau217 as a minimally invasive diagnostic and prognostic biomarker for AD, with potential utility in clinical practice and trials. Highlights: Non-demented presenilin-1 E280A carriers have higher plasma tau phosphorylated at threonine 217 (p-tau217) than do age-matched non-carriers. Higher baseline p-tau217 is associated with greater future amyloid positron emission tomography (PET) pathology burden. Higher baseline p-tau217 is associated with greater future tau PET pathology burden. Higher baseline p-tau217 is associated with worse future memory performance.
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| 2. |
- Berron, David, et al.
(författare)
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Hippocampal subregional thinning related to tau pathology in early stages of Alzheimer’s disease
- 2022
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 18:S1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Subregions in the medial temporal lobe (MTL) are affected early by Alzheimer’s disease (AD) pathology and subject to grey matter atrophy. Measuring the earliest AD-related atrophy in the hippocampus is challenging as region-of-interest (ROI) analyses of hippocampal subregional volumes collapse across voxels within anatomical subregions. PET imaging studies, however, report accumulation of tau pathology between anatomical subregions in the earliest disease stages (Berron et al., 2021) fitting reports from the neuropathological literature (Lace et al., 2019; Ravikumar et al., 2021). Thus, sensitive in vivo methods of point-wise structural measures are needed in order to detect the earliest hippocampal thinning in AD along the anterior-posterior as well as the medial-lateral hippocampal axis. Method: Here we analyzed data from 76 amyloid-beta negative (Ab-) cognitively normal (CN), 46 Ab+ CN individuals and 25 Ab+ patients with mild cognitive impairment (MCI) from the BioFINDER-2 study, who underwent 7 Tesla T2-weighted structural magnetic resonance imaging, tau positron emission tomography imaging (using 18F-RO-948) and cognitive assessments. First, we segmented hippocampal subfields and extrahippocampal subregions. Second, we calculated point-wise hippocampal thickness estimates (Diers et al.) of hippocampal subfields subiculum, cornu ammonis (CA)1, CA2 and CA3 on the level of the hippocampal body. Thirdly, we extracted local tau-PET SUVR from Area 35 (A35), entorhinal cortex and amygdala. Finally, we assessed relationships between hippocampal local thickness and tau accumulation as well as cognitive performance. Result: Our analyses revealed earliest hippocampal thinning associated with tau accumulation in an area spanning the boundary of subiculum and CA1 at the level of the anterior hippocampal body. Ab+ MCI patients showed more posterior thinning in comparison to Ab- CU participants. Median thickness in an ROI comprising vertices with A35 tau-related thinning (A35-TauThinning-ROI) was significantly lower in MCI Ab+ and tended to be lower in CU Ab+ compared to CU Ab-. Higher median thickness in the hippocampal A35-TauThinning-ROI, but not whole CA1 nor subiculum thickness, was associated with better 10-Word-Delayed-Recall and higher PACC scores. Conclusion: Our results suggest that tau-related thinning of hippocampal subregions can be observed already in early disease stages. Tau-related point-wise thickness measures were more sensitive compared to volumetric measures of anatomical subregions.
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| 3. |
- Binette, Alexa Pichet, et al.
(författare)
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Amyloid-associated increases in soluble tau is a key driver in accumulation of tau aggregates and cognitive decline in early Alzheimer
- 2022
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 18:S1
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Tidskriftsartikel (refereegranskat)abstract
- Background: For optimal design of anti-amyloid-β (Aβ) and anti-tau clinical trials, it is important to understand how Aβ and soluble phosphorylated tau (p-tau) relate to the accumulation of tau aggregates assessed with positron emission tomography (PET) and subsequent cognitive decline across the Alzheimer's disease (AD) continuum. Method: We included 327 participants from the Swedish BioFINDER-2 cohort with cerebrospinal fluid (CSF) p-tau217, Aβ-PET, longitudinal tau-PET, and longitudinal cognition. The main groups of interest were Aβ-positive non-demented participants and AD dementia patients (Table 1 and Figure 1), and analyses were conducted separately in each group. First, we investigated how soluble p-tau217 and regional Aβ-PET were associated with tau-PET rate of change across the 200 brain parcels from the Schaefer atlas. We also tested the mediating effect of p-tau217 between Aβ-PET and tau-PET change. Second, we investigated how soluble p-tau217 and tau-PET change related to change in cognition, and mediation between these variables. Result: In early AD stages (non-demented participants), increased concentration of soluble p-tau217 was the main driver of accumulation of insoluble tau aggregates across the brain (measured as tau-PET rate of change), beyond the effect of regional Aβ-PET and baseline tau-PET (Figure 2A-C). Further, averaged across all regions, soluble p-tau217 mediated 54% of the association between Aβ and tau aggregation (Figure 2D). Higher soluble p-tau217 concentrations were also associated with cognitive decline, which was mediated by faster increase of tau aggregates (Figure 3). Repeating the same analyses in the AD dementia group, results were different. In late stage of AD, when Aβ fibrils and soluble p-tau levels have plateaued, soluble p-tau217 was not associated with accumulation of tau aggregates beyond baseline tau-PET (Figure 4A), and cognitive decline was driven by the accumulation rate of insoluble tau aggregates and not soluble p-tau217 (Figure 4B-C). Conclusion: Soluble p-tau is a main driver of tau aggregation and future cognitive decline in earlier stages of AD, whereas tau aggregation accumulation is more likely an important driver of disease in later stages. Overall, our data suggest that therapeutic approaches reducing soluble p-tau levels might be most favorable in early AD.
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| 4. |
- Boada, Mercè, et al.
(författare)
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Complementary pre-screening strategies to uncover hidden prodromal and mild Alzheimer's disease : Results from the MOPEAD project
- 2022
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 18:6, s. 1119-1127
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The Models of Patient Engagement for Alzheimer's Disease (MOPEAD) project was conceived to explore innovative complementary strategies to uncover hidden prodromal and mild Alzheimer's disease (AD) dementia cases and to raise awareness both in the general public and among health professionals about the importance of early diagnosis. Methods: Four different strategies or RUNs were used: (a) a web-based (WB) prescreening tool, (2) an open house initiative (OHI), (3) a primary care–based protocol for early detection of cognitive decline (PC), and (4) a tertiary care–based pre-screening at diabetologist clinics (DC). Results: A total of 1129 patients at high risk of having prodromal AD or dementia were identified of 2847 pre-screened individuals (39.7%). The corresponding proportion for the different initiatives were 36.8% (WB), 35.6% (OHI), 44.4% (PC), and 58.3% (DC). Conclusion: These four complementary pre-screening strategies were useful for identifying individuals at high risk of having prodromal or mild AD.
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| 5. |
- Chen, Yaohua Sophie, et al.
(författare)
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COVID-19-related loneliness and social isolation in caregivers of people with brain health challenges : The CLIC-Caregiver Global Survey
- 2021
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Ingår i: Alzheimer's & dementia : the journal of the Alzheimer's Association. - : Wiley. - 1552-5279. ; 17
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Prior to COVID-19, >90% of caregivers of people with brain health challenges (dementia, mental ill health, intellectual disability) experienced high levels of distress, burden, loneliness and social isolation. The COVID-19 pandemic has significantly increased these impacts, particularly since these caregivers are often older and physically vulnerable themselves. The aim of this cross-sectional study is to explore coping and caregiver burden, loneliness and social isolation in caregivers of people with brain health challenges during the COVID-19 pandemic. METHOD: CLIC-Caregiver was a cross-sectional, online, and global survey (June 2nd - November 15th , 2020) using self-administered questionnaires directed at informal caregivers of people with long-term brain health challenges. The study was embedded within a larger survey of loneliness and social isolation for general public ('Comparing Loneliness and Isolation in COVID-19' (CLIC)), including validated loneliness and isolation tools. Translated into ten different languages such as Arabic, French, Romanian, etc, the survey was disseminated over 100 countries. Respondents were included in the CLIC-caregiver sub-study if they answered yes to the question 'Do you provide care and support to a family member or friend with a long-term or life-limiting health problem or disability (including mental health)'. The CLIC project received the initial global ethical approval from Ulster University. The data were fully anonymized. RESULT: From the CLIC main study, 5243 (25%) identified themselves as caregivers. This proportion varied in different countries, from 12 % in Romania to 65% in France. 2323 (44%) had care recipients with dementia, 1761 with physical conditions (disability or long-term illness), 832 with enduring mental health problems, and 404 with intellectual disability. Measures of caregiver burden, loneliness and social isolation will be compared across geographic regions, sociodemographic factors, and risk factors for poor outcomes sought. Findings will be distributed to relevant stakeholders in the form of a project report, with region and country-specific outcomes. This will support recommendations and actions supporting caregivers of people with brain health challenges. CONCLUSION: This represents the largest, most widespread survey on the impact of the COVID-19 pandemic on caregivers of people with long-term conditions to date. It will be an important resource for support agencies and to inform policy.
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| 6. |
- Chen, Yaohua Sophie, et al.
(författare)
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COVID-19-related loneliness, social isolation and burden in informal caregivers worldwide
- 2022
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 18:S8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Informal caregivers may experience high levels burden. Prior to COVID-19, loneliness and social isolation, and especially the discordance between them, were recognized for rapid aging-related cognitive decline. The COVID-19 has significantly increased social isolation and loneliness in caregivers. Thus, we aimed to explore the variables that were associated with higher care burden among all caregivers and only among caregivers for people living with dementia, and whether the increased burden could be associated with a discrepancy between loneliness and social isolation. Method: ‘Comparing Loneliness and Isolation in COVID-19’ was an online global survey of over 20,000 respondents, including 5243 caregivers across 50 countries with enduring brain or/and physical health conditions. We first used a multilevel modelling to identify risk factors associated with higher burden. Then, we defined profiles of discrepancy between loneliness and social isolation, based on the differences between standardized score on a scale of loneliness and of social connectedness and estimated the association between the discrepancy and higher burden. Result: In our sample, 74% of caregivers were female, 44% were caring for people with dementia, and 22% for people with multiple conditions, including dementia. The most prevalent age group was 60-69 years old. Factors significantly associated with higher care burden were being female, having poorer financial situation, worse mental health during the pandemic, caring for people with dementia or intellectual disabilities, caring in the same home, being diagnosed with COVID, and changes of care abilities. 40% of caregivers consistently reported high level of loneliness and social isolation, 38% reported consistent lower levels of both, and two groups reported discordance (low levels of loneliness and high social isolation in 13%; high levels of loneliness and mild social isolation in 12%). The latter group was at the highest risk of self-reported increased and intense care burden. Conclusion: This represents the largest, most widespread survey on the impact of the COVID-19 pandemic on caregivers of people with long-term conditions to date and reflects the importance of capturing the nuances in the relationship between loneliness and social isolation in caregivers. It will be an important resource for support agencies and to inform policy.
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| 7. |
- Collij, Lyduine E., et al.
(författare)
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Quantification of [18F]florbetaben amyloid-PET imaging in a mixed memory clinic population : The ABIDE project
- 2023
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 19:6, s. 2397-2407
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: We investigated amyloid-burden quantification in a mixed memory clinic population. Methods: [18F]Florbetaben amyloid-PET (positron emission tomography) scans of 348 patients were visually read and quantified using the Centiloid (CL) method. General linear models were used to assess CL differences across syndromic and etiological diagnosis. Linear mixed models were fitted to assess the predictive value of visual read (VR) and CL on longitudinal Mini-Mental Status Examination (MMSE). Results: CL was associated with syndromic (F = 4.42, p = 0.014) and etiological diagnosis (F = -12.66, p < 0.001), with Alzheimer's disease (AD) patients showing the highest amyloid burden (62.9 ± 27.5), followed by dementia with Lewy bodies (DLB) (25.3 ± 35.5) and cardiovascular disease (CVD) (16.7 ± 24.5), and finally frontotemporal lobe degeneration (FTLD) (5.0 ± 17.22, t = –12.66, p < 0.001). CL remained predictive of etiological diagnosis (t = –2.41, p = 0.017) within the VR+ population (N = 157). VR was not a significant predictor of MMSE (t = –1.53, p = 0.13) for the SCD population (N = 90), whereas CL was (t = -3.30, p = 0.001). Discussion: The extent of amyloid pathology through quantification holds clinical value, potentially in the context of differential diagnosis as well as prognosis.
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| 8. |
- Cullen, Nicholas C., et al.
(författare)
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Test-retest variability of plasma biomarkers in Alzheimer's disease and its effects on clinical prediction models
- 2023
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Ingår i: Alzheimers & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 19:3, s. 797-806
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION The effect of random error on the performance of blood-based biomarkers for Alzheimer's disease (AD) must be determined before clinical implementation. METHODS We measured test-retest variability of plasma amyloid beta (A beta)42/A beta 40, neurofilament light (NfL), glial fibrillary acidic protein (GFAP), and phosphorylated tau (p-tau)217 and simulated effects of this variability on biomarker performance when predicting either cerebrospinal fluid (CSF) A beta status or conversion to AD dementia in 399 non-demented participants with cognitive symptoms. RESULTS Clinical performance was highest when combining all biomarkers. Among single-biomarkers, p-tau217 performed best. Test-retest variability ranged from 4.1% (A beta 42/A beta 40) to 25% (GFAP). This variability reduced the performance of the biomarkers (approximate to Delta AUC [area under the curve] -1% to -4%) with the least effects on models with p-tau217. The percent of individuals with unstable predicted outcomes was lowest for the multi-biomarker combination (14%). DISCUSSION Clinical prediction models combining plasma biomarkers-particularly p-tau217-exhibit high performance and are less effected by random error. Individuals with unstable predicted outcomes ("gray zone") should be recommended for further tests.
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| 9. |
- Dore, Vincent, et al.
(författare)
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CenTauRz : A standardized quantification of tau PET scans
- 2022
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 18:S1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Over the past decade, several PET tracers were developed to visualise and quantify tau pathology in vivo. However, all these tracers have distinct off-target binding, different dynamic ranges and likely different levels of non-specific binding resulting in large variability in semiquantification. We propose to standardise the sampling and the quantification across all available tau tracers. Method: 549 participants underwent tau scans with either 18F-FTP (Cognitively Unimpaired (CU)=54/AD=14), 18F-MK6240 (CU=186/AD=89), 18F-PI2620 (CU=17/AD=21), 18F-PM-PBB3 (CU=30/AD=28), 18F-GTP1 (CU=7/AD=38) or 18F-RO948 (CU=35/AD=30). All CU individuals were Aβ- and all AD were Aβ+. The tau scans were spatially normalized using CapAIBL and the cerebellar cortex was used as reference region. We constructed a “universal” tau mask from the intersection of all the specific tau tracer masks, after subtracting AD from CU. All tau PET studies were sampled with a Mesial Temporal (MTL) and a Meta Temporal (MetaT) composites constrained by the universal mask. For each tracer and in composite, the mean and standard deviation of the Aβ- CU SUVR for each tau tracer were used to generate z-scores (CenTauRz). Result: Using a threshold of 2 CenTauRz in the MetaT regions, all tracers highly discriminated Aβ+ AD from Aβ- CU (ACC=[0.94-1], sens=[0.84-1], spec=[0.96-1]) with mean CenTauRz for the different AD cohorts ranging from 8 to 14. Lower accuracy was observed in the MTL (ACC=[0.78-1]) due to lower sensitivity in some cohorts [0.65-1] however, the specificity was similar to that in the MetaT composite (spec=[0.94,1]). Conclusion: All tracers exhibited comparably high discriminative power to separate Aβ+ AD from Aβ- CU, where AD Aβ+ displayed a consistent range of CenTauRz across tracers. However, there were some differences between cohorts. For example, different PET scanners, with different sensitivities were used. For some cohorts, scans were selected as extreme representative cases, while for others the scans were more representative of clinical settings, with AD patients at early stages (with low or negative tau scans) or with suspected hippocampal sparing subtype that likely explains the lower accuracy in the MTL for some cohorts. Further studies with larger cohorts to validate the universal mask and CenTauRz scale are ongoing.
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| 10. |
- Eikelboom, Willem S., et al.
(författare)
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Evaluating the DICE method to improve early recognition and treatment of neuropsychiatric symptoms in early Alzheimer’s disease
- 2022
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 18:S8
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Tidskriftsartikel (refereegranskat)abstract
- Background: While neuropsychiatric symptoms (NPS) are common in early Alzheimer’s disease (AD), they are currently underdiagnosed and undertreated in the memory clinic. Therefore, we evaluated the effectiveness of the Describe, Investigate, Create, Evaluate (DICE™) approach to structure and standardize the care for NPS in AD in the memory clinic. Method: A total of 60 community-dwelling patients with MCI, AD dementia, or AD/VaD dementia were enrolled with their caregivers in two waves (Table-1). The first wave (n = 36) received care as usual and served as a control group, while the second wave of patients (n = 24, of which n = 20 have currently completed the study) underwent the DICE method. We applied the DICE method during two visits in which NPS were assessed, underlying causes were examined, and patients and caregivers were instructed on management strategies to deal with NPS, which were evaluated after one month. Outcomes were assessed after three and six months. Primary outcomes were quality of life of patients (QoL-AD) and caregivers (Carerqol-7D). Secondary outcomes included caregiver burden (Perseverance time), NPS prevalence and severity (NPI-Q & BEHAVE-AD), NPS-related distress (NPI-Q), competence managing NPS (additional NPI-Q item), and psychotropic drug use. We used linear mixed models to examine differences in outcomes at group-level and reliable change index to examine which participants in the intervention group showed reliable improvement in the primary outcomes. Result: We found no significant differences between the two groups in change in quality of life or any of the secondary outcomes (all p>0.05, Table-2). A proportion of the intervention group showed reliable improvement in quality of life of patients (n = 6/20) and caregivers (n = 7/20). At baseline, these patients tended to show higher NPS burden and their caregivers reported more NPS-related distress and lower feelings of competence while managing NPS compared to participants that did no show reliable improvement. Conclusion: This Stage 2 efficacy study shows no benefits of the DICE method on in early AD at group-level, but suggest that particular participants might benefit from this approach. Data will be re-analyzed when all intervention group participants have completed the study and will be extended with qualitative data investigating NPS-related knowledge and management styles of participants.
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