Papers by Bernard Hanseeuw
Alzheimers & Dementia, Dec 1, 2020
Background: A number of biomarkers have shown utility for predicting cognitive decline and conver... more Background: A number of biomarkers have shown utility for predicting cognitive decline and conversion from mild cognitive impairment (MCI) to dementia. However, few studies have investigated the effectiveness of biomarkers combinations and their individual contributions for predicting rate of memory decline. This study evaluated
Acta Neurologica Belgica, Oct 28, 2021
Neurological symptoms depend on the topography of the lesions in the nervous system, hence the im... more Neurological symptoms depend on the topography of the lesions in the nervous system, hence the importance of brain imaging for neurologists. Neurological treatment, however, depends on the biological nature of the lesions. The development of radiotracers specific for the proteinopathies observed in neurodegenerative disorders is, therefore, crucially important for better understanding the relationships between the pathology and the clinical symptoms, as well as the efficacy of therapeutical interventions. The tau protein is involved in several neurodegenerative disorders, that can be distinguished both biologically and clinically as the type of tau isoforms and filaments observed in brain aggregates, and the brain regions affected differ between tauopathies. Over the past few years, several tracers have been developed for imaging tauopathies with positron emission tomography. The present review aims to compare the binding properties of these tracers, with a specific focus on how these properties might be relevant for neurologists using these biomarkers to characterize the pathology of patients presenting with clinical symptoms suspect of a neurodegenerative disorder.
HAL (Le Centre pour la Communication Scientifique Directe), May 11, 2020
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
info:eu-repo/semantics/publishe
ABSTRACT Background: New diagnostic criteria for predemential Alzheimer's disease... more ABSTRACT Background: New diagnostic criteria for predemential Alzheimer's disease (AD) advocate the use of biomarkers. However, the benefit of using biomarkers has not been clearly demonstrated in clinical practice. Objective: To investigate whether a combination of biomarkers may be helpful in classifying a population of non-demented patients attending a Memory Clinic. Methods: Sixty non-demented patients were compared with 31 healthy elderly subjects. All subjects underwent a neuropsychological examination, brain 3T magnetic resonance imaging, and [F18]-fluorodeoxyglucose and [F18]-flutemetamol positron emission tomography. According to their performance on memory, language, executive, and visuo-spatial domains, the patients were classified as mild cognitive impairment (amnestic, non-amnestic, single, or multiple domain) or subjective cognitive impairment. Patients were then classified according to the National Institute on Aging-Alzheimer's Association (NIA-AA) criteria, using the normalized mean hippocampal volume (Freesurfer), [F18]-FDG PALZAD, and [F18]-flutemetamol standard uptake value ratio (SUVr) (cut-off at the 10th percentile of controls). The standard of truth was the clinical status at study entry (patient versus control). Results: The sensitivity/specificity of the clinical classification was 65/84%. The NIA-AA criteria were applicable in 85% of patients and 87% of controls. For biomarkers the best sensitivity (72%) at a fixed specificity of 84% was achieved by a combination of the three biomarkers. The clinical diagnosis was reconsidered in more than one third of the patients (42%) as a result of including the biomarker results. Conclusions: Application of the new NIA-AA AD diagnostic criteria based on biomarkers in an unselected sample of non-demented patients attending a Memory Clinic was useful in allowing for a better classification of the subjects.
Journal of The International Neuropsychological Society, Nov 1, 2016
Objectives: Relatively few studies have investigated relationships between performance on clinica... more Objectives: Relatively few studies have investigated relationships between performance on clinical memory measures and indexes of underlying neuropathology related to Alzheimer's disease (AD). This study investigated predictive relationships between Free and Cued Selective Reminding Test (FCSRT) cue efficiency (CE) and free-recall (FR) measures and brain amyloid levels, hippocampal volume (HV), and regional cortical thickness. Methods: Thirty-one older controls without memory complaints and 60 patients presenting memory complaints underwent the FCSRT, amyloid imaging using [F 18 ]-flutemetamol positron emission tomography, and surface-based morphometry (SBM) using brain magnetic resonance imaging. Three groups were considered: patients with high (Aβ+ P) and low (Aβ− P) amyloid load and controls with low amyloid load (Aβ− C). Results: Aβ+ P showed lower CE than both Aβ− groups, but the Aβ− groups did not differ significantly. In contrast, FR discriminated all groups. SBM analyses revealed that CE indexes were correlated with the cortical thickness of a wider set of left-lateralized temporal and parietal regions than FR. Regression analyses demonstrated that amyloid load and left HV independently predicted FCSRT scores. Moreover, CE indexes were predicted by the cortical thickness of some regions involved in early AD, such as the entorhinal cortex. Conclusions: Compared to FR measures, CE indexes appear to be more specific for differentiating persons on the basis of amyloid load. Both CE and FR performance were predicted independently by brain amyloid load and reduced left HV. However, CE performance was also predicted by the cortical thickness of regions known to be atrophic early in AD.
Alzheimers & Dementia, Dec 1, 2020
BackgroundPatients with mild cognitive impairment (MCI) are at‐risk of progression to Alzheimer’s... more BackgroundPatients with mild cognitive impairment (MCI) are at‐risk of progression to Alzheimer’s dementia (AD), particularly if they have elevated amyloid (Aβ), the hallmark pathology of AD. However, a proportion of Aβ‐negative MCI also progress to dementia in clinical practice. We sought to investigate (1) whether subthreshold Aβ load, brain metabolism, or atrophy could predict progression to dementia in patients with Aβ‐negative MCI, and (2) whether the regional pattern was distinct from patients with Aβ‐positive MCI.MethodSeventy‐nine older adults underwent [18F]‐FDG‐PET to estimate their brain metabolism, [18F]‐Flutemetamol‐PET to assess their Aβ load, and 3D‐T1 MRI. Aβ load was expressed in Centiloids and a threshold of 43 corresponding to visual assessment was used to define Aβ positivity. FDG data were expressed as Standardized Uptake Value ratios (SUVr) scaled on pons with partial volume correction. MRI‐PET co‐registration was performed with PetSurfer. Eight Aβ‐negative MCI progressed to dementia after four years. We compared their FDG and thicknesses maps to 25 Aβ‐negative normal older adults, 31 Aβ‐negative stable MCI, and 15 Aβ‐positive MCI who also progressed to AD dementia after four years. Demographics and follow‐up durations are provided in Table1.ResultSubthreshold Aβ did not predict progression to dementia among Aβ‐negative MCI (p=0.81). Vertex‐wise analyses highlighted temporo‐parietal hypometabolism in the Aβ‐negative MCI who progressed to dementia, compared to stable Aβ‐negative controls (Fig. 1), and to a lesser extent compared to stable Aβ‐negative MCI patients (Fig. 2). However, their cerebral metabolism was similar to the one observed in Aβ‐positive MCI (Fig.3). Finally, the regional pattern of cortical thinning in progressive Aβ‐negative MCI was less typical of AD (Fig.4). Adjusting for age, sex, e4 status, or Aβ did not modify these observations.ConclusionTemporoparietal FDG predicts subsequent dementia in Aβ‐negative MCI patients, suggesting a close association with clinical progression. The FDG regional pattern is however not specific of Aβ pathophysiology.
The Journal of Nuclear Medicine, 2016
OBJECTIVES: Although visual analysis of Amyloid PET has been considered sufficient to discriminat... more OBJECTIVES: Although visual analysis of Amyloid PET has been considered sufficient to discriminate Alzheimer’s patients from healthy elderly subjects, early stage of the degenerative process (MCI stade), exhibiting fewer amyloid deposits, may be more challenging to interpret. In this situation, a robust quantitative analysis may not only be helpful to reinforce the visual analysis but also to allow longitudinal evaluation of the amyloid load in this population. METHODS: As part of a academic study evaluating the impact of biomarkers to stratify MCI patients, 30 healthy controls (70±5.5 y) and 62 (70.8±8.0 y) patients presenting Mild Cognitive Impairement (MCI) were imaged 90 min PI with F18-Flutemetamol scan (GE Healthcare; target ID 185 MBq). SUVr (neocortex/cerebellum) values computed with step-by-step analysis based on several PMOD 3.2 tools (see previously published data) were compared to those obtained with a more recent evolution of the PMOD software (PNEURO 3.5) implementing several useful improvements for clinical translation (semi-automatic workflow, more accurate MRI segmentation for VOI delineation). However, those methodological changes could also potentially influence the results, reason why a front-to-front comparison was performed. RESULTS: PMOD 3.2 and PNEURO 3.5 SUVr (Mean±SD/Median/PC90) of the control group were respectively 1.40±0.23/1.33/1.69 and 1.29±0.16/1.26/1.49, both significantly different from the MCI group analysis (1.67±0.39/1.57(P=0.002) and 1.55±0.35/1.42 (p<0.0001)). Despite a good correlation (r2: 0.95), pooled SUVr PNEURO 3.5 values were significantly lower than the previously computed PMOD 3.2 values (P< 0.0001; bias(d): -0.12, SD of bias: 0.09; 95% limits of agreement: from -0.29 to 0.06). The SUVmean of the cerebellar region of reference (Mean±SD/Median) was not statistically different between controls and MCI: 0.59±0.15/0.59 vs 0.63±0.15/0.61 (P=0.28) for PMOD 3.2 and 0.63±0.14/0.64 vs 0.67±0.14/0.65 (P=0.42) for PNEURO 3.5. However, a significant difference was observed (P<0.0001) between the two methods of analysis, with slightly higher cerebellar SUVmean values using PNEURO 3.5 (bias: 0.04; SD of bias: 0.04; 95% limits of agreement: from -0.03 to 0.12). PC90 SUVr of the control group used as discriminating cutoff to separate positive from negative amyloid scans, perfectly correlates with the binary visual analysis scans in all cases, whatever the method used. Finally, SUVr workflow reproducibility using PNEURO 3.5 was also tested between two independent observers for n=24 scans selected ad random, with excellent results (bias: 0.002; SD of bias:0.012; 95% limits of Agreement, from -0.021 to 0.026 (-1.22 to 1.53%)). CONCLUSION: SUVr computation based of PNEURO 3.5 seems a easy way to quantify the neocortical amyloid load in MCI patients, providing similar results than the visual scan reading but with the advantage to be independent of the physician’s degree of expertise
Alzheimers & Dementia, Dec 1, 2022
Alzheimer's & Dementia
BackgroundBrain function can be assessed using both resting‐state functional magnetic resonance i... more BackgroundBrain function can be assessed using both resting‐state functional magnetic resonance imaging (rs‐fMRI) and Fluorodeoxyglucose (FDG) PET imaging. The associations between these biomarkers and their evolution with Alzheimer’s disease (AD) are unclear. We aimed to evaluate the associations between the default mode network (DMN) connectivity and glucose metabolism in mild cognitive impairment (MCI) patients with (Aβ+) and without (Aβ‐) AD pathology.MethodForty MCI patients (19 Aβ‐/21 Aβ+) performed between 2 to 4 rs‐fMRI acquisitions with an average follow‐up duration of 15 months. At baseline, DMN metabolism was estimated using [18F]‐FDG‐PET SUVr of the isthmus cingulate region‐of‐interest extracted from the Desikan‐Killiany atlas; and Aβ was measured using [18F]‐Flutemetamol‐PET. We used a Centiloid‐threshold>26 to define Aβ+. Multiple regressions were used to assess the FDG‐fMRI associations in the DMN, comparing the two subgroups using FDG‐Aβ interaction models. Table ...
Alzheimer's & Dementia, 2020
BackgroundDetecting Alzheimer’s disease (AD) before the onset of symptoms is crucial for the deve... more BackgroundDetecting Alzheimer’s disease (AD) before the onset of symptoms is crucial for the development of effective treatment (1). As biomarkers are costly and/or invasive, there is a need for cost‐efficient and non‐invasive methods that can indicate which individuals need further examination. We present a running project that aims at developing a screening tool applicable to the general population by automatically analyzing the history of electronic messages such as WhatsApp and e‐mails over a period of several years prior to the analysis.MethodIn the first phase of the project (model construction), 30 prodromal or mildly demented AD patients (with biomarkers‐confirmed diagnosis) and 30 clinically normal elderly volunteers are recruited to donate their electronic message histories. Data is gathered and processed according to the General Data Protection Regulation and only sent messages are considered, which are codified to hide personal information. Automatic linguistic analyses ...
Alzheimer's & Dementia, 2021
BackgroundMK‐6240 is a promising second‐generation tau‐positron emission tomography (PET) tracer ... more BackgroundMK‐6240 is a promising second‐generation tau‐positron emission tomography (PET) tracer for evaluation of cerebral tauopathy in patients with and without cognitive impairment. To further validate the use of MK‐6240 in Memory Clinics, we aimed to evaluate the association between MK‐6240 PET results and well‐validated cerebrospinal fluid (CSF) tau and amyloid protein quantifications.MethodWe acquired MK‐6240 tau‐PET and 3D‐T1 MRI in 44 patients attending our Memory Clinic who accepted lumbar puncture. PET data were processed using PMOD 4.1 Neuro tool: we created three clusters of brain segments based on Braak pathological stages (1‐2; 3‐4 and 5‐6). Standardized uptake value ratio (SUVr) measures were calculated without partial volume correction for these three regions, using cerebellar grey matter as region of reference. SUVr measures in the three regions were correlated to CSF measures of total tau, phospho‐tau 181 (P‐tau) and amyloid (Aβ42) proteins. Linear regressions were...
Alzheimer's & Dementia, 2021
The integrity of face identity recognition (FIR) in prodromal Alzheimer’s disease (prAD) is incon... more The integrity of face identity recognition (FIR) in prodromal Alzheimer’s disease (prAD) is inconsistent in the literature, and the cognitive processes underpinning a potential impairment remain elusive. The concepts of pattern separation (PS) and pattern completion (PC) offer an interesting insight in this respect, since efficient FIR implies that facial identities are stored in at least partly distinct representations (corresponding to a PS process) and to fill‐in the currently perceived facial pattern based on these mnemonic representations (corresponding to the PC process). The goal of our study was therefore to investigate FIR in prAD patients with a PC and PS paradigm. In addition, we aimed to verify that prAD patients were able to individuate faces in a task that does not involve any long‐term memory component.
The Journal of Nuclear Medicine, 2016
Objectives: Although visual analysis of amyloid PET has been considered sufficient to discriminat... more Objectives: Although visual analysis of amyloid PET has been considered sufficient to discriminate Alzheimer patients from healthy elderly subjects, early stages of Alzheimer degenerative process, ongoing years before the clinical stage, may exhibit fewer amyloid deposits. The level of amyloid load in MCI patients due to AD should therefore be more challenging to detect reason why cortical sub-region analysis could theoretically be considered to detect focal amyloid deposits, not yet spread to the whole cerebral cortex. Methods: In this study, the result of global neocortical index SUVr computed with PNEURO 3.5 was compared to 10 different cortical sub-regions, known to visually show high discriminant F18-Flutemetamol uptake in AD patients compared to healthy elderly controls. 30 healthy controls and 62 MCI were reviewed for the analysis. The ten regions, regrouping left and right structures (to limit the analysis), were designed as such: 1_NC: whole neocortex 2_NC+SP: neocortex + specific regions (described hereunder) 3_SP: sum of specific regions: orbitofrontal cortex, striatum (caudate nucleus & putamen), superior parietal cortex and posterior cingulate cortex. 4_PSCP: superior parietal cortex and posterior cingulate cortex. 5_PC: parietal cortex. 6_FC: frontal cortex. 7_OFC: orbitofrontal cortex. 8_OC: occipital cortex. 9_TC: temporal cortex. 10_ST: striatum (caudate nucleus & putamen). The gold-standard method to characterize positive or negative amyloid scan stayed the visual reading as recommended. Global and regional cut-off values were arbitrary defined at the PC-90 value of the control group to consider a positive amyloid load. Results: The regional statistics and comparison between the control and MCI groups for each sub-region are given below: (Table1) In comparison to the gold standard visual analysis, the percentage of positivity in global and sub-regional cortical volumes of interest was calculated, based on previously defined PC90 cut-off values. Results are summarized in the table below: (Table2) Conclusion: Even if each sub-region showed a significant difference between control and MCI groups, the last results demonstrated no particular interest to perform additional sub-regional amyloid quantification beside the global neocortex quantification, due to the high consistency of positive or negative pattern in nearly all regions of interest
The main objective of this report is to test the hypothesis that the adoption of an active inform... more The main objective of this report is to test the hypothesis that the adoption of an active information-seeking practice related to the health crisis on social networks can be understood as a risk practice in the Covid-19 infodemic. A second objective is to identify the existence of different vulnerability profiles in the infodemic and to understand the information practices associated with these different profiles at risk of misinformation. The approach adopted is therefore firstly a comparative approach between different types of profile. It is not a question of carrying out a longitudinal study representative of the evolution of the French-speaking Belgian population's experience of the crisis. The CoviCom survey is a four-wave questionnaire survey that was conducted in French-speaking Belgium between 30 March 2020 (i.e. 12 days after the entry into force of the first containment in Belgium) and 29 March 2021. In total, the survey collected 10,148 responses to the four waves o...
Managing the health crisis we are facing goes far beyond managing the coronavirus epidemic. The l... more Managing the health crisis we are facing goes far beyond managing the coronavirus epidemic. The lockdown measures implemented in response to the virus propagation have resulted in broad medical and societal impacts. In addition to the epidemic, an “infodemic” has been generated and is now spreading. For most individuals, this enormous and incessant flow of true and false information is difficult to manage. Moreover, academic physicians now occupy the media space, a situation they are not familiar with. In an academic effort to draw the attention of the Belgian government and experts to the central role of social sciences and humanities in getting out of the crisis, a neurologist has partnered with media sociologists as well as a psychologist specialized in anxiety disorders to better understand the impact of (mis-)information on people’s behavior, with a particular focus on the differences that exist between the general public and health professionals.
Since the WHO declared the COVID-19 pandemic on March 11, 2020, the novel coronavirus, SARS-CoV-2... more Since the WHO declared the COVID-19 pandemic on March 11, 2020, the novel coronavirus, SARS-CoV-2, has profoundly impacted public health and the economy worldwide. But there are not the only ones to be hit. The COVID-19 pandemic has also substantially altered mental health, with anxiety symptoms being one of the most frequently reported problems. Especially, the number of people reporting anxiety symptoms increased significantly during the first lockdown-phase compared to similar data collected before the pandemic. Yet, most of these studies relied on a unitary approach to anxiety, wherein its different constitutive features (i.e., symptoms) were tallied into one sum-score, thus ignoring any possibility of interactions between them. Therefore, in this study, we seek to map the associations between the core features of anxiety during the first weeks of the first Belgian COVID-19 lockdown-phase (n = 2,829). To do so, we implemented, in a preregistered fashion, two distinct computation...
![Research paper thumbnail of Defining a Centiloid scale threshold predicting long-term progression to dementia in patients attending the memory clinic: an [18F] flutemetamol amyloid PET study](https://attachments.academia-assets.com/110858821/thumbnails/1.jpg)
European Journal of Nuclear Medicine and Molecular Imaging, 2020
Purpose To evaluate cerebral amyloid-β(Aβ) pathology in older adults with cognitive complaints, v... more Purpose To evaluate cerebral amyloid-β(Aβ) pathology in older adults with cognitive complaints, visual assessment of PET images is approved as the routine method for image interpretation. In research studies however, Aβ-PET semi-quantitative measures are associated with greater risk of progression to dementia; but until recently, these measures lacked standardization. Therefore, the Centiloid scale, providing standardized Aβ-PET semi-quantitation, was recently validated. We aimed to determine the predictive values of visual assessments and Centiloids in non-demented patients, using long-term progression to dementia as our standard of truth. Methods One hundred sixty non-demented participants (age, 54–86) were enrolled in a monocentric [18F] flutemetamol Aβ-PET study. Flutemetamol images were interpreted visually following the manufacturers recommendations. SUVr values were converted to the Centiloid scale using the GAAIN guidelines. Ninety-eight persons were followed until dementia ...
Selon l'OMS, l'épidémie de Covid-19 est accompagnée d'une « infodémie », c’est-à-dire... more Selon l'OMS, l'épidémie de Covid-19 est accompagnée d'une « infodémie », c’est-à-dire un flux énorme et incessant d'informations, vraies et fausses, difficiles à gérer pour les individus. Cette infodémie est un problème car elle peut générer une incompréhension du virus ainsi que de l'anxiété et empêcher l'adoption de pratiques efficaces de lutte contre la pandémie. Cette étude, réalisée entre le 30 mars et le 10 avril auprès de 1.817 Belges francophones par l'Observatoire de Recherche sur les Médias et le Journalisme (ORM – UCLouvain), mesure l'ampleur de l'infodémie en Belgique francophone.
Médecine Nucléaire, 2020
Resume L’objective de ce travail est d’etablir la valeur de la tomographie par emissions de posit... more Resume L’objective de ce travail est d’etablir la valeur de la tomographie par emissions de positons avec traceur de la plaque amyloide pour predire l’evolution a long terme vers la demence de patients non dements consultant a la Clinique de la Memoire.
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Papers by Bernard Hanseeuw