Agnes Flöel's research while affiliated with Deutsches Zentrum für Neurodegenerative Erkrankungen and other places

Publications (384)

Article
Objectives: Telemedicine is frequently used to provide remote neurological expertise for acute stroke workup and was associated with better functional outcomes when combined with a stroke unit system-of-care. We investigated whether such system-of-care yields additional benefits when implemented on top of neurological competence already available...
Article
Introduction: Supplementation with spermidine may support healthy aging, but elevated spermidine tissue levels were shown to be an indicator of Alzheimer’s disease (AD). Methods: Data from 659 participants (age range: 21–81 years) of the population-based Study of Health in Pomerania TREND were included. We investigated the association between sperm...
Article
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Background: Limiting the ability to engage in social interaction, aphasia increases the risk of poststroke depression and may prevent classical forms of psychotherapy. Our parallel-group, blinded-assessment, quasi-randomized controlled trial explores the feasibility and potential efficacy of intensive social interaction as a means to alleviate pos...
Poster
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A 3-step hierarchical Bayes analysis of the frequency of apraxia of speech in patients with chronic post-stroke aphasia. Step 1: meta-analysis of published frequency data; step 2: survey of expert opinions; step 3: secondary auditory-perceptual analysis of speech samples from a representative sample of patients with post-stroke aphasia, > 6 months...
Article
Background: Oscillatory rhythms during sleep, such as slow oscillations (SOs) and spindles and, most importantly, their coupling, are thought to underlie processes of memory consolidation. External slow oscillatory transcranial direct current stimulation (so-tDCS) with a frequency of 0.75 Hz has been shown to improve this coupling and memory conso...
Article
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Background Understanding how SARS-CoV-2 affects respiratory centres in the brainstem may help to preclude assisted ventilation for patients in intensive care setting. Viral invasion appears unlikely, although autoimmunity has been implicated, the responsible antigens remain unknown. We previously predicted the involvement of three epitopes within d...
Preprint
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Gender biases are well documented in science and typically favor male scientists. In this context, a particularly pervasive gender bias is undercitation of publications authored by women, resulting in profound negative effects on academic visibility and career advancement. This bias has been well documented in fields where author gender distributio...
Article
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Introduction Chemotherapy-induced polyneuropathy (CIPN) and post-chemotherapy cognitive impairment (PCCI) are frequent side effects of paclitaxel treatment. CIPN/PCCI are potentially irreversible, reduce quality of life and often lead to treatment limitations, which affect patients’ outcome. We previously demonstrated that paclitaxel enhances an in...
Article
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Background Vector-borne diseases (VBDs) represent an emerging global threat to public health due to the geographical expansion of arthropod vectors. The study aims to assess the seroprevalence of selected vector-borne pathogens (VBPs) in different groups of outdoor workers and the occupational risk factors for exposure to arthropod bites. Methods...
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Metrological methods for word learning list tests can be developed with an information theoretical approach extending earlier simple syntax studies. A classic Brillouin entropy expression is applied to the analysis of the Rey's Auditory Verbal Learning Test RAVLT (immediate recall), where more ordered tasks-with less entropy-are easier to perform....
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The current pandemic has exerted an unprecedented psychological impact on the world population, and its effects on mental health are a growing concern. The present study aims to evaluate psychological well-being (PWB) during the COVID-19 crisis in university workers with one or more diseases likely to increase the risk of severe outcomes in the eve...
Article
Background Trajectories of decline across different socio-cognitive domains in healthy older adults and in pathological aging conditions have not been investigated. This was addressed in the present systematic review and meta-analysis. Methods MEDLINE, Web of Science Core Collection, CENTRAL, and PsycInfo were searched for studies investigating so...
Article
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 i...
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Introduction: With the worldwide increase of life expectancy leading to a higher proportion of older adults experiencing age-associated deterioration of cognitive abilities, the development of effective and widely accessible prevention and therapeutic measures has become a priority and challenge for modern medicine. Combined interventions of cogni...
Article
Importance: Developing interventions against age-related memory decline and for older adults experiencing neurodegenerative disease is one of the greatest challenges of our generation. Spermidine supplementation has shown beneficial effects on brain and cognitive health in animal models, and there has been preliminary evidence of memory improvemen...
Article
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We analyzed symptoms and comorbidities as predictors of hospitalization in 710 outpatients in North-East Germany with PCR-confirmed SARS-CoV-2 infection. During the first 3 days of infection, commonly reported symptoms were fatigue (71.8%), arthralgia/myalgia (56.8%), headache (55.1%), and dry cough (51.8%). Loss of smell (anosmia), loss of taste (...
Article
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Attempts to enhance human memory and learning ability have a long tradition in science. This topic has recently gained substantial attention because of the increasing percentage of older individuals worldwide and the predicted rise of age-associated cognitive decline in brain functions. Transcranial brain stimulation methods, such as transcranial m...
Article
Ein psychometrisch fundiertes Verfahren zur direkten Erfassung der verbalen Kommunikationsfähigkeit bei Aphasie ist der Amsterdam-Nijmegen Everyday Language Test (ANELT). Angesichts einer zunehmenden Verbreitung des ANELT in Forschung und Klinik ist eine Standardisierung der Auswertung wünschenswert. In der vorliegenden Untersuchung wurden, basiere...
Article
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Subjective cognitive decline (SCD), as expressed by older adults, is associated with negative affect, which, in turn, is a likely risk factor for Alzheimer’s Disease (AD). This study assessed the associations between negative affective burden, cognitive functioning, and functional connectivity in networks vulnerable to AD in the context of SCD. Old...
Preprint
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Introduction Breast cancer is the most common form of cancer in women. A considerable number of women with breast cancer who have been treated with chemotherapy, subsequently develop neurological symptoms such as concentration and memory difficulties (also known as ‘chemobrain’). Currently, there are no validated therapeutic approaches available to...
Article
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Neural mechanisms of behavioral improvement induced by repeated transcranial direct current stimulation (tDCS) combined with cognitive training are yet unclear. Previously, we reported behavioral effects of a 3-day visuospatial memory training with concurrent anodal tDCS over the right temporoparietal cortex in older adults. To investigate interven...
Article
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Introduction A substantial number of patients diagnosed with COVID-19 experience long-term persistent symptoms. First evidence suggests that long-term symptoms develop largely independently of disease severity and include, among others, cognitive impairment. For these symptoms, there are currently no validated therapeutic approaches available. Cogn...
Article
Apraxia of speech is a motor speech disorder that occurs after lesions to the left cerebral hemisphere, most often concomitant with aphasia. It requires specific approaches in the study of its physiological and neuroanatomical basis and special expertise in clinical care. Knowing its prevalence in patients with aphasia after stroke is therefore rel...
Article
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Introduction: Given rapid global population aging, developing interventions against age-associated cognitive decline is an important medical and societal goal. We evaluated a cognitive training protocol combined with transcranial direct current stimulation (tDCS) on trained and non-trained functions in non-demented older adults. Methods: Fifty-s...
Article
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The Virtual Brain (TVB) is now available as open-source services on the cloud research platform EBRAINS. It offers software for constructing, simulating and analysing brain network models including the TVB simulator; magnetic resonance imaging (MRI) processing pipelines to extract structural and functional brain networks; combined simulation of lar...
Article
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During slow-wave sleep, the brain is in a self-organized regime in which slow oscillations (SOs) between up- and down-states travel across the cortex. While an isolated piece of cortex can produce SOs, the brain-wide propagation of these oscillations are thought to be mediated by the long-range axonal connections. We address the mechanism of how SO...
Article
This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To assess the efficacy of different non‐pharmacological interventions for people with primary progressive aphasia (PPA) on global language abilities, word retrieval, functional communication, cognition, depressive symptoms, quality of life, and adverse events....
Article
Construct specification equations (CSEs), providing a comprehensive understanding of the construct purported to be measured and how a collection of items works together causally, are candidate ‘recipes for certified reference materials’ (CRM). Analogous to the role of CRMs in areas such as chemistry and material properties, CSEs appear to provide m...
Article
To ensure reliable diagnosis and treatment consistently throughout healthcare, metrological quality assurance is essential. There are, however, many observations in the social sciences and healthcare, such as the memory tests studied here, which have been ‘claimed’ to be measurements but in fact have not been fully metrologically legitimated. We ha...
Article
The extent to which existing legacy memory tests are accurate and sensitive in detecting early cognitive decline is questionable. This reflects the wider picture in neurodegenerative conditions where clinical rating scales have not been developed for early‐stage disease. Item banks delivered through computer adaptive tests can help. But, in order t...
Article
Subjective Cognitive Decline (SCD) may represent an early, pre‐clinical manifestation of Alzheimer’s disease (Jessen et al., 2014), possibly accompanied by detrimental changes in white matter (WM) microstructure (Brueggen et al., 2019). Neuroprotective effects of increased external supply of spermidine were demonstrated in aged animal models (Madeo...
Article
The NeuroMET project aims are to develop: 1) a “NeuroMET memory metric” metrologically validated with clinical laboratory data that will be implemented into a app for delivery of cognitive tests 2) 7T magnetic resonance imaging and spectroscopy protocols and measurement uncertainty frameworks to be implemented into clinic and applied to larger stud...
Article
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Background: This randomized controlled trial investigated if uni- and bihemispheric transcranial direct current stimulation (tDCS) of the motor cortex can enhance the effects of visuo-motor grip force tracking task training and transfer to clinical assessments of upper extremity motor function. Methods: In a randomized, double-blind, sham-controlle...
Article
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Objective: Extracellular vesicles (EV) are sub-1 μm bilayer lipid coated particles and have been shown play a role in long-term cardiovascular outcome after ischemic stroke. However, the dynamic change of EV after stroke and their implications for functional outcome have not yet been elucidated. Methods: Serial blood samples from 110 subacute ische...
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Citation: Wortha, S.M.; Wüsten, K.A.; Witte, V.A.; Bössel, N.; Keßler, W.; Vogelgesang, A.; Flöel, A. Gastrointestinal Hormones in Healthy Adults: Reliability of Repeated Assessments and Interrelations with Eating Habits and Physical Activity. Nutrients 2021, 13, 3809. https://doi.org/10.3390/
Article
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Background and Purpose: In the setting of acute ischemic stroke, increased blood-brain barrier permeability (BBBP) as a sign of injury is believed to be associated with increased risk of poor outcome. Pre-clinical studies show that selected serum biomarkers including C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNFα)...
Preprint
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Certain neurophysiological characteristics of sleep, in particular slow oscillations (SO), sleep spindles, and their temporal coupling, have been well characterized and associated with human memory formation. Delta waves, which are somewhat higher in frequency and lower in amplitude compared to SO, have only recently been found to play a critical r...
Article
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Obesity imposes serious health risks and involves alterations in resting-state functional connectivity of brain networks involved in eating behavior. Bariatric surgery is an effective treatment, but its effects on functional connectivity are still under debate. In this pre-registered study, we aimed to determine the effects of bariatric surgery on...
Article
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Background: Inflammatory markers, such as C-reactive Protein (CRP), Interleukin-6 (IL-6), tumor necrosis factor (TNF)-alpha and fibrinogen, are upregulated following acute stroke. Studies have shown associations of these biomarkers with increased mortality, recurrent vascular risk, and poor functional outcome. It is suggested that physical fitness...
Article
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Subjective cognitive decline (SCD) is considered an early risk stage for dementia due to Alzheimer's disease (AD) and the development of pathological brain changes, such as the aggregation of amyloid-beta (amyloid-β) plaques. This study evaluates the association between specific features of SCD and cerebral amyloid-β load measured by positron emiss...
Article
Vaccine-induced immune thrombotic thrombocytopenia (VITT) is a severe adverse effect of ChAdOx1 nCoV-19 COVID-19 vaccine (Vaxzevria) and COVID-19 vaccine Janssen (Ad26.COV2.S), and associated with unusual thrombosis. VITT is caused by anti-platelet factor 4 (PF4) antibodies activating platelets through their FcgRIIa receptors. Antibodies activating...
Article
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Background: Subjective cognitive decline (SCD) is considered a risk factor for Alzheimer's disease (AD), highlighting the need for identifying and ranking effective interventions. This was addressed in a systematic review and network meta-analysis (NMA) of pharmacological and non-pharmacological interventions for SCD. Methods: MEDLINE, Web of Sc...
Article
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Background Head and brain anatomy have been related to e-field strengths induced by transcranial electrical stimulation (tES). Individualization based on anatomic factors require high-quality structural magnetic resonance images, which are not always available. Head circumference (HC) can serve as an alternative means, but its linkage to electric f...
Article
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Introduction Stroke is the leading neurological cause of adult long-term disability in Europe. Even though functional consequences directly related to neurological impairment are well studied, post-stroke trajectories of functional health according to the International Classification of Functioning, Disability and Health are poorly understood. Part...
Article
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Introduction Many clinical studies reporting accelerometry data use sum score measures such as percentage of time spent in moderate to vigorous activity which do not provide insight into differences in activity patterns over 24 hours, and thus do not adequately depict circadian activity patterns. Here, we present an improved functional data analysi...
Article
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MRI-based vessel size imaging (VSI) allows for in-vivo assessment of cerebral microvasculature and perfusion. This exploratory analysis of vessel size (VS) and density (Q; both assessed via VSI) in the subacute phase of ischemic stroke involved sixty-two patients from the BAPTISe cohort (‘Biomarkers And Perfusion--Training-Induced changes after Str...
Preprint
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Background: Some recipients of ChAdOx1 nCoV-19 COVID-19 Vaccine AstraZeneca develop antibody-mediated vaccine-induced thrombotic thrombocytopenia (VITT), associated with cerebral venous and other unusual thrombosis resembling autoimmune heparin-induced thrombocytopenia. A prothrombotic predisposition is also observed in Covid-19. We explored whethe...
Preprint
Full-text available
Obesity imposes serious health risks and involves alterations in resting-state functional connectivity of brain networks involved in eating behavior. Bariatric surgery is an effective treatment, but its effects on functional connectivity are still under debate. In this pre-registered study, we aimed to determine the effects of bariatric surgery on...
Article
Background Previous studies suggest that genetic polymorphisms and aging modulate inter-individual variability in brain stimulation-induced plasticity. However, the relationship between genetic polymorphisms and behavioral modulation through transcranial direct current stimulation (tDCS) in older adults remains poorly understood. Objective Link in...
Preprint
Full-text available
The Virtual Brain (TVB) is now available as open-source cloud ecosystem on EBRAINS, a shared digital research platform for brain science. It offers services for constructing, simulating and analysing brain network models (BNMs) including the TVB network simulator; magnetic resonance imaging (MRI) processing pipelines to extract structural and funct...
Preprint
Full-text available
Background: Transcranial direct current stimulation (tDCS) may improve motor recovery after stroke. This study investigated if uni- and bihemispheric tDCS of the motor cortex can enhances fine motor training outcome and transfer to clinical assessments of upper motor function. Methods: In a randomized, double-blinded, sham-controlled trial, forty c...
Article
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Study Objectives Aging is associated with detrimental changes in sleep physiology, a process accelerated in Alzheimer's disease (AD). Fine-tuned temporal interactions of NREM slow oscillations (SO) and spindles were shown to be particularly important for memory consolidation, and to deteriorate in healthy older adults. Whether this oscillatory inte...
Article
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Variations in head and brain anatomy determine the strength and distribution of electrical fields in humans and may account for inconsistent behavioral and neurophysiological results in transcranial electrical stimulation (tES) studies. However, it is insufficiently understood which anatomical features contribute to the variability of the modelled...
Conference Paper
Subjective cognitive decline (SCD) is considered an early risk stage for the development of Alzheimer's disease (AD) and pathological brain alterations, including the aggregation of amyloid‐β plaques (Jessen et al., Alzheimer's & Dementia 2014). This prospective study evaluates the association between specific features of SCD, including severity of...
Article
Research on non‐invasive methods of modulating age‐associated cognitive decline has yielded promising results. Current evidence shows that transcranial direct current stimulation (tDCS), if administered with concurrent cognitive training, may successfully modulate cognitive performance. In the TrainStim‐Cog trial, we investigated in healthy older a...
Article
The combination of transcranial direct current stimulation (tDCS) with memory training has gained attention as a means for cognitive enhancement in the older population. Neuroimaging studies have identified changes in local brain activity and functional network connectivity as potential underlying mechanisms of tDCS‐induced performance improvement....
Article
Subjective Cognitive Decline (SCD) may represent the earliest clinical manifestation of Alzheimer’s disease (AD) (Jessen et al. 2014). In individuals with SCD and mild cognitive impairment (MCI), changes in white matter (WM) microstructure have been shown using diffusion weighted (DW) imaging (Brueggen et al. 2019). However, it is unknown to which...
Article
Individuals with subjective cognitive decline (SCD) are at high risk of developing Alzheimer's disease (AD) (Jessen et al., 2014). Changes in cerebral perfusion, particularly cerebral blood flow (CBF), are a feature of AD and has also been shown in pre‐dementia stages (Binnewijzend et al., 2016). This study investigates regional CBF and its associa...
Preprint
Full-text available
During slow-wave sleep, the brain is in a self-organized regime in which slow oscillations (SOs) between up- and down-states propagate across the cortex. We address the mechanism of how SOs emerge and can recruit large parts of the brain using a whole-brain model based on empirical connectivity data. Individual brain areas generate SOs that are ind...
Article
Full-text available
Background Given the growing older population worldwide, and the associated increase in age-related diseases, such as Alzheimer’s disease (AD), investigating non-invasive methods to ameliorate or even prevent cognitive decline in prodromal AD is highly relevant. Previous studies suggest transcranial direct current stimulation (tDCS) to be an effect...
Article
Full-text available
Non-invasive transcranial stimulation of cerebellum and primary motor cortex (M1) has been shown to enhance motor learning. However, the mechanisms by which stimulation improves learning remain largely unknown. Here, we sought to shed light on the neural correlates of transcranial direct current stimulation (tDCS) during motor learning by simultane...
Article
Full-text available
Ageing involves significant neurophysiological changes that are both systematic while at the same time exhibiting divergent trajectories across individuals. These changes underlie cognitive impairments in elderly while also affecting the response of aged brains to interventions like transcranial direct current stimulation (tDCS). While the cognitiv...
Article
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Introduction: Outcome measures are key to tailor rehabilitation goals to the stroke patient's individual needs and to monitor poststroke recovery. The large number of available outcome measures leads to high variability in clinical use. Currently, an internationally agreed core set of motor outcome measures for clinical application is lacking. Ther...
Article
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Background: Both diagnosis and treatment of neurological emergencies require neurological expertise and are time-sensitive. The lack of fast neurological expertise in regions with underserved infrastructure poses a major barrier for state-of-the-art care of patients with acute neurological diseases and leads to disparity in provision of health car...
Preprint
Full-text available
Non-invasive transcranial stimulation of cerebellum and primary motor cortex (M1) has been shown to enhance motor learning. However, the mechanisms by which stimulation improves learning remain largely unknown. Here, we sought to shed light on the neural correlates of transcranial direct current stimulation (tDCS) during motor learning by simultane...
Article
Full-text available
Severe acute respiratory syndrome-related coronavirus 2 infection has been associated with Guillain-Barré syndrome. We investigated here the potential mechanism underlying the virus-induced damage of the peripheral nervous systems by searching the viral amino acid sequence for peptides common to human autoantigens associated with immune-mediated po...
Article
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Background The natural polyamine spermidine, known to be important for cellular function, decreases during aging. Previous research has demonstrated beneficial impact of spermidine intake on memory functions in both animal models and humans, suggesting that spermidine may be a preventive approach to delay age-related cognitive decline and possibly...
Article
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The global increase in neurodegenerative disorders is one of the most crucial public health issues. Oral polyamine intake was shown to improve memory performance which is thought to be mediated at least in part via increased autophagy induced in brain cells. In Alzheimer's Disease, T-cells were identified as important mediators of disease pathology...