ORCID Profile
0000-0002-0139-5388
Current Organisations
German Center for Neurodegenerative Diseases
,
Universidade de Santa Cruz do Sul
,
University College London
,
Otto-von-Guericke-Universität Magdeburg Medizinische Fakultät
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Publisher: Cold Spring Harbor Laboratory
Date: 30-10-2019
DOI: 10.1101/263020
Abstract: Abnormal salience processing has been suggested to contribute to the formation of positive psychotic symptoms in schizophrenia and related conditions. Previous research utilising reward learning or anticipation paradigms has demonstrated cortical and subcortical abnormalities in people with psychosis, specifically in the prefrontal cortex, the dopaminergic midbrain and the striatum. In these paradigms, reward prediction errors attribute motivational salience to stimuli. However, little is known about possible abnormalities across different forms of salience processing in psychosis patients, and whether any such abnormalities involve the dopaminergic midbrain. The aim of our study was, therefore, to investigate possible alterations in psychosis in neural activity in response to various forms of salience: novelty, negative emotion, targetness (task-driven salience) and rareness/deviance. We studied 14 antipsychotic naïve participants with first episode psychosis, and 37 healthy volunteers. During fMRI scanning, participants performed a visual oddball task containing these four forms of salience. Psychosis patients showed abnormally reduced signalling in the substantia nigra/ventral tegmental area (SN/VTA) for novelty, negative emotional salience and targetness reduced striatal and occipital (lingual gyrus) signalling to novelty and negative emotional salience, reduced signalling in the amygdala, anterior cingulate cortex and parahippocamal gyrus to negative emotional salience, and reduced cerebellar signalling to novelty and negative emotional salience. Our results indicate alterations of several forms of salience processing in patients with psychosis in the midbrain SN/VTA, with additional subcortical and cortical regions also showing alterations in salience signalling, the exact pattern of alterations depending on the form of salience in question.
Publisher: Elsevier BV
Date: 2020
Publisher: Research, Society and Development
Date: 02-01-2023
Abstract: Infection control teams collect and produce information on epidemiologic surveillance for prevention of Healthcare Associated Infections (HAIs). Value Stream Mapping (VSM) is a Lean method for developing process through flow efficiency. The aim of the study was to use VSM to identify opportunities for improvement in the infection control department. Flow of information and infection control activities were reviewed using VSM and a questionnaire, where time required for each task was measured. The actual VSM went through multidisciplinary analysis and an ideal VSM was created without considering resource limits. The ideal VSM was reviewed to identify the improvements easily implemented and the ones that would require more time or resources. The actual VSM analysis addressed work overload for Key Performance Indicators (KPI) production, data management (fragmentation, access and redundant work, storage, time between tasks, time typing) and tasks performed retrospectively, when less information is available and with no opportunity to correct protocol deviation. The implementation of the ideal VSM provided a faster and more efficient HAIs analysis, London protocol for HAI cases and surgical prophylaxis evaluation became real time tasks, and all surgical surveillance was improved. A mobile app was proposed as an intervention and became a long-term project. If completely implemented, the ideal VSM would result in 15.7 less work hours/month, having the working time optimized for patient care. VSM is an important tool for epidemiologic surveillance in infection control allowing better data management, continuous workflow, and new information production with potentially fewer work hours.
Publisher: Wiley
Date: 29-01-2020
DOI: 10.1002/MDS.27987
Abstract: Sporadic degenerative ataxia patients fall into 2 major groups: multiple system atrophy with predominant cerebellar ataxia (MSA-C) and sporadic adult-onset ataxia (SAOA). Both groups have cerebellar volume loss, but little is known about the differential involvement of gray and white matter in MSA-C when compared with SAOA. The objective of this study was to identify structural differences of brain gray and white matter between both patient groups. We used magnetic resonance imaging to acquire T1-weighted images and diffusion tensor images from 12 MSA-C patients, 31 SAOA patients, and 55 healthy controls. Magnetic resonance imaging data were analyzed with voxel-based-morphometry, tract-based spatial statistics, and tractography-based regional diffusion tensor images analysis. Whole-brain and cerebellar-focused voxel-based-morphometry analysis showed gray matter volume loss in both patient groups when compared with healthy controls, specifically in the cerebellar areas subserving sensorimotor functions. When compared with controls, the SAOA and MSA-C patients showed white matter loss in the cerebellum, whereas brainstem white matter was reduced only in the MSA-C patients. The tract-based spatial statistics revealed reduced fractional anisotropy within the pons and cerebellum in the MSA-C patients both in comparison with the SAOA patients and healthy controls. In addition, tractography-based regional analysis showed reduced fractional anisotropy along the corticospinal tracts in MSA-C, but not SAOA. Although in our cohort extent and distribution of gray and white matter loss were similar between the MSA-C and SAOA patients, magnetic resonance imaging data showed prominent microstructural white matter involvement in the MSA-C patients that was not present in the SAOA patients. Our findings highlight the significance of microstructural white matter changes in the differentiation between both conditions. © 2020 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.
Publisher: Springer Science and Business Media LLC
Date: 17-04-2017
Publisher: Springer Science and Business Media LLC
Date: 07-02-2018
Publisher: SAGE Publications
Date: 11-05-2016
Abstract: Brain imaging is essential for the diagnosis and characterization of cerebral small vessel disease. Several magnetic resonance imaging markers have therefore emerged, providing new information on the diagnosis, progression, and mechanisms of small vessel disease. Yet, the reproducibility of these small vessel disease markers has received little attention despite being widely used in cross-sectional and longitudinal studies. This review focuses on the main small vessel disease-related markers on magnetic resonance imaging including: white matter hyperintensities, lacunes, dilated perivascular spaces, microbleeds, and brain volume. The aim is to summarize, for each marker, what is currently known about: (1) its reproducibility in studies with a scan–rescan procedure either in single or multicenter settings (2) the acquisition-related sources of variability and, (3) the techniques used to minimize this variability. Based on the results, we discuss technical and other challenges that need to be overcome in order for these markers to be reliably used as outcome measures in future clinical trials. We also highlight the key points that need to be considered when designing multicenter magnetic resonance imaging studies of small vessel disease.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-07-2020
DOI: 10.1212/WNL.0000000000010142
Abstract: To determine the nature and extent of minor neuropsychological deficits in patients with subjective cognitive decline (SCD) and their association with CSF biomarkers of Alzheimer disease (AD). We analyzed data from n = 449 cognitively normal participants (n = 209 healthy controls, n = 240 patients with SCD) from an interim data release of the German Center for Neurodegenerative Diseases Longitudinal Cognitive Impairment and Dementia Study (DELCODE). An extensive neuropsychological test battery was applied at baseline for which we established a latent, 5 cognitive domain factor structure comprising learning and memory, executive functions, language abilities, working memory, and visuospatial functions. We compared groups in terms of global and domain-specific performance and correlated performance with different CSF markers of AD pathology. We observed worse performance (Cohen d = ≈0.25–0.5, adjusted for age, sex differences with analysis of covariance) in global performance, memory, executive functions, and language abilities for the SCD group compared to healthy controls. In addition, worse performance in these domains was moderately ( r = ≈0.3) associated with lower CSF β-amyloid 42/40 and CSF β-amyloid 42 hosphorylated tau181 in the whole s le and specifically in the SCD subgroup. Within the spectrum of clinically unimpaired (i.e., before mild cognitive impairment) cognitive performance, SCD is associated with minor deficits in memory, executive function, and language abilities. The association of these subtle cognitive deficits with AD CSF biomarkers speaks to their validity and potential use for the early detection of underlying preclinical AD.
Publisher: Springer Science and Business Media LLC
Date: 21-03-2019
Publisher: Springer Science and Business Media LLC
Date: 21-09-2018
DOI: 10.1038/S41398-018-0250-3
Abstract: Abnormal salience processing has been suggested to contribute to the formation of positive psychotic symptoms in schizophrenia and related conditions. Previous research utilising reward learning or anticipation paradigms has demonstrated cortical and subcortical abnormalities in people with psychosis, specifically in the prefrontal cortex, the dopaminergic midbrain and the striatum. In these paradigms, reward prediction errors attribute motivational salience to stimuli. However, little is known about possible abnormalities across different forms of salience processing in psychosis patients, and whether any such abnormalities involve the dopaminergic midbrain. The aim of our study was, therefore, to investigate possible alterations in psychosis in neural activity in response to various forms of salience: novelty, negative emotion, targetness (task-driven salience) and rareness/deviance. We studied 14 antipsychotic naïve participants with first episode psychosis, and 37 healthy volunteers. During fMRI scanning, participants performed a visual oddball task containing these four forms of salience. Psychosis patients showed abnormally reduced signalling in the substantia nigra/ventral tegmental area (SN/VTA) for novelty, negative emotional salience and targetness reduced striatal and occipital (lingual gyrus) signalling to novelty and negative emotional salience, reduced signalling in the amygdala, anterior cingulate cortex and parahippocamal gyrus to negative emotional salience, and reduced cerebellar signalling to novelty and negative emotional salience. Our results indicate alterations of several forms of salience processing in patients with psychosis in the midbrain SN/VTA, with additional subcortical and cortical regions also showing alterations in salience signalling, the exact pattern of alterations depending on the form of salience in question.
Publisher: Springer Science and Business Media LLC
Date: 25-08-2017
DOI: 10.1038/S41598-017-08779-0
Abstract: Previous studies have demonstrated increased tau plasma levels in patients with Alzheimer’s disease (AD) and mild cognitive impairment (MCI) due to AD. Much less is known whether increased tau plasma levels can already be detected in the pre-MCI stage of subjective cognitive decline (SCD). In the present study we measured tau plasma levels in 111 SCD patients and 134 age- and gender-matched cognitively healthy controls participating in the DZNE (German Center for Neurodegenerative Diseases) longitudinal study on cognition and dementia (DELCODE). Tau plasma levels were measured using ultra-sensitive, single-molecule array (Simoa) technology. We found no significant different tau plasma levels in SCD (3.4 pg/ml) compared with healthy controls (3.6 pg/ml) after controlling for age, gender, and education (p = 0.137). In addition, tau plasma levels did not correlate with Aβ42 (r = 0.073 p = 0.634), tau (r = −0.179 p = 0.240), and p-tau181 (r = −0.208 p = 0.171) cerebrospinal fluid (CSF) levels in a subgroup of 45 SCD patients with available CSF. In conclusion, plasma tau is not increased in SCD patients. In addition, the lack of correlation between tau in plasma and CSF in the examined cohort suggests that tau levels are affected by different factors in both biofluids.
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.NEUROIMAGE.2016.05.024
Abstract: Quantitative susceptibility mapping (QSM) has recently emerged as a novel magnetic resonance imaging (MRI) method to detect non-haem iron deposition, calcifications, demyelination and vascular lesions in the brain. It has been suggested that QSM is more sensitive than the more conventional quantifiable MRI measure, namely the transverse relaxation rate, R2*. Here, we conducted the first high-resolution, whole-brain, simultaneously acquired, comparative study of the two techniques using 7Tesla MRI. We asked which of the two techniques would be more sensitive to explore global differences in tissue composition in elderly adults relative to young subjects. Both QSM and R2* revealed strong age-related differences in subcortical regions, hippoc us and cortical grey matter, particularly in superior frontal regions, motor remotor cortices, insula and cerebellar regions. Within the basal ganglia system-but also hippoc us and cerebellar dentate nucleus-, QSM was largely in agreement with R2* with the exception of the globus pallidus. QSM, however, provided superior anatomical contrast and revealed age-related differences in the thalamus and in white matter, which were otherwise largely undetected by R2* measurements. In contrast, in occipital cortex, age-related differences were much greater with R2* compared to QSM. The present study, therefore, demonstrated that in vivo QSM using ultra-high field MRI provides a novel means to characterise age-related differences in the human brain, but also combining QSM and R2* using multi-gradient recalled echo imaging can potentially provide a more complete picture of mineralisation, demyelination and/or vascular alterations in aging and disease.
Publisher: Wiley
Date: 08-2016
Publisher: Wiley
Date: 31-07-2019
Publisher: Springer Science and Business Media LLC
Date: 06-04-2020
DOI: 10.1038/S41467-020-15410-W
Abstract: The locus coeruleus (LC), the origin of noradrenergic modulation of cognitive and behavioral function, may play an important role healthy ageing and in neurodegenerative conditions. We investigated the functional significance of age-related differences in mean normalized LC signal intensity values (LC-CR) in magnetization-transfer (MT) images from the Cambridge Centre for Ageing and Neuroscience (Cam-CAN) cohort - an open-access, population-based dataset. Using structural equation modelling, we tested the pre-registered hypothesis that putatively noradrenergic (NA)-dependent functions would be more strongly associated with LC-CR in older versus younger adults. A unidimensional model (within which LC-CR related to a single factor representing all cognitive and behavioral measures) was a better fit with the data than the a priori two-factor model (within which LC-CR related to separate NA-dependent and NA-independent factors). Our findings support the concept that age-related reduction of LC structural integrity is associated with impaired cognitive and behavioral function.
Publisher: Oxford University Press (OUP)
Date: 15-02-2018
DOI: 10.1093/BRAIN/AWY008
Publisher: Wiley
Date: 2018
Location: United Kingdom of Great Britain and Northern Ireland
Location: Germany
No related grants have been discovered for Emrah Duzel.