References of "Jaspar, Mathieu"
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See detailEmergency Medical Services: When Fatigue Becomes The Norm.
Berastegui, Pierre ULiege; Jaspar, Mathieu ULiege; GHUYSEN, Alexandre ULiege

Conference (2017, June 27)

BACKROUND: Emergency Medical Services (EMS) routinely work at the very limit of their capacity due to growing emergency rooms visits and residents’ shortage. In this context, EMS workers are regularly ... [more ▼]

BACKROUND: Emergency Medical Services (EMS) routinely work at the very limit of their capacity due to growing emergency rooms visits and residents’ shortage. In this context, EMS workers are regularly asked to work more than 10 hours a day, on varying shifts and with short recuperation breaks. Two approaches can be used to reduce fatigue-related risk: reducing the likelihood a fatigued operator is working (i.e. fatigue reduction), or reducing the likelihood a fatigued operator will make an error (i.e. fatigue proofing). In Emergency Medical Services, formal risk control mainly focuses on reduction strategies such as reducing work hours while proofing strategies develops as an implicit element of the safety system. OBJECTIVE: Our purpose is to identify individual proofing and reduction strategies used by emergency residents and to investigate how they relate to fatigue, performance and patient safety indicators. METHODS: First, we conducted 4 focus-group sessions with a total of 25 EMS residents to elicit perceived consequences of fatigue and strategies used to cope with them. Focus group results were used to design a questionnaire assessing how often EMS residents personally used any of the strategies reported during sessions. Second, we administered the questionnaire to a larger sample and conducted a prospective observational study with a repeated within-subjects component. A total of 45 EMS residents participated in the study for a total of 400 shifts analyzed. We gathered sleep diaries, subjective sleepiness, reaction time, self-reported medical errors and performance ratings at different time point during both day and night shift using an android-based application. Sleep time and activity levels were confirmed using wrist actigraphy. DISCUSSION: We will discuss what can be drawn from our results in terms of individual and collective resilience processes with a focus on the potential for implementation of more formal processes at a system level.  [less ▲]

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See detailRelating pessimistic memory predictions to Alzheimer’s disease brain structure
Genon, Sarah ULiege; Simon, Jessica ULiege; Bahri, Mohamed Ali ULiege et al

Poster (2017, March 23)

Patients with Alzheimer’s disease (AD) show impairment of episodic memory and related metacognitive processes. The present study examined subjective metacognitive judgments preceding objective memory ... [more ▼]

Patients with Alzheimer’s disease (AD) show impairment of episodic memory and related metacognitive processes. The present study examined subjective metacognitive judgments preceding objective memory retrieval and investigated the neural correlates of pessimistic predictions for successfully retrieved memories in AD patients. AD patients and healthy older participants provided predictive judgements on their recognition performance before retrieval of famous (semantic) and recently learned (episodic) names. Correlations between grey matter volume (GMV) in T1 images and behavioural scores were examined with multivariate (PLS) and univariate (GLM) analyses in AD patients. AD patients showed a significant proportion of successful name recognition preceded by pessimistic prediction (Prediction_low_hits) in episodic memory. PLS revealed that behavioural pattern in AD patients was related with a mainly right lateralized pattern of GMV decrease including medial temporal lobe and posterior cingulate cortex, but also right ventrolateral prefrontal cortex (VLPFC). GLM further confirmed that pessimistic prediction negatively correlated with GMV in VLPFC. Thus, impaired monitoring processes (possibly influenced by inaccurate beliefs) allowing inferences about one’s own memory performance are primarily related to decrease GMV in VLPFC in AD patients. [less ▲]

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See detailIMPACT OF IMAGE BRIGHTNESS REDUCTION ON PERCEIVED QUALITY OF 3D EXPERIENCE FOR 3D CINEMA SPECTATORS
Loock, Severin; Grogna, David ULiege; Jaspar, Mathieu ULiege et al

in International Conference on 3D Imaging (IC3D) (2017)

3D movies are calibrated to meet a certain screen bright- ness standard. Therefore, what would be the consequences on the quality of the 3D experience for spectators watching a 3D movie when movie ... [more ▼]

3D movies are calibrated to meet a certain screen bright- ness standard. Therefore, what would be the consequences on the quality of the 3D experience for spectators watching a 3D movie when movie theaters do not respect this standard? First, we attempted to better understand which factors were important for a spectator by conducting an experiment where participants watched a 3D movie and filled out an exploratory questionnaire. Then, we aimed to investigate the link between image brightness loss and the quality of the 3D experience as perceived by the spectator. First results show no perceived difference in the quality of the 3D experience between a nor- mal brightness and a brightness decreased by 10% for four factors, i.e. (1) the appreciation of the movie, (2) the con- tent of the movie, (3) the 3D quality of the movie, and (4) the quality of the 3D experience in general. [less ▲]

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See detailRelating pessimistic memory predictions to Alzheimer’s disease brain structure
Genon, Sarah ULiege; Simon, Jessica ULiege; Bahri, Mohamed Ali ULiege et al

in Cortex : A Journal Devoted to the Study of the Nervous System & Behavior (2016), 85

Patients with Alzheimer’s disease (AD) show impairment of episodic memory and related metacognitive processes. The present study examined subjective metacognitive judgments preceding objective memory ... [more ▼]

Patients with Alzheimer’s disease (AD) show impairment of episodic memory and related metacognitive processes. The present study examined subjective metacognitive judgments preceding objective memory retrieval and investigated the neural correlates of pessimistic predictions for successfully retrieved memories in AD patients. AD patients and healthy older participants provided predictive judgements on their recognition performance before retrieval of famous (semantic) and recently learned (episodic) names. Correlations between grey matter volume (GMV) in T1 images and behavioural scores were examined with multivariate (PLS) and univariate (GLM) analyses in AD patients. AD patients showed a significant proportion of successful name recognition preceded by pessimistic prediction (Prediction_low_hits) in episodic memory. PLS revealed that behavioural pattern in AD patients was related with a mainly right lateralized pattern of GMV decrease including medial temporal lobe and posterior cingulate cortex, but also right ventrolateral prefrontal cortex (VLPFC). GLM further confirmed that pessimistic prediction negatively correlated with GMV in VLPFC. Thus, impaired monitoring processes (possibly influenced by inaccurate beliefs) allowing inferences about one’s own memory performance are primarily related to decrease GMV in VLPFC in AD patients. [less ▲]

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See detailAge-related differences in the dynamics of cortical excitability and cognitive inhibition during prolongedwakefulness
Gaggioni, Giulia ULiege; Chelllappa, S.; Ly, J. et al

Conference (2016, September)

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See detailLocal modulation of human brain responses by circadian rhythmicity and sleep debt
Muto, Vincenzo ULiege; Jaspar, Mathieu ULiege; Meyer, Christelle et al

in Science (2016), 351(6300),

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See detailEffects of aging on task- and stimulus-related cerebral attention networks
Kurth, Sophie ULiege; Majerus, Steve ULiege; Bastin, Christine ULiege et al

in Neurobiology of Aging (2016), 44

Interactions between a dorsal attention (DAN) and a ventral attention cerebral network (VAN) have been reported in young participants during attention or short term memory (STM) tasks. Since it remains an ... [more ▼]

Interactions between a dorsal attention (DAN) and a ventral attention cerebral network (VAN) have been reported in young participants during attention or short term memory (STM) tasks. Since it remains an under-investigated question, age effects on DAN and VAN activity and their functional balance were explored during performance of a STM task. Older and young groups showed similar behavioral patterns of results. At the cerebral level, DAN activation increased as a function of increasing STM load in both groups, suggesting preserved activity in DAN during healthy aging. Age-related over-recruitment in regions of the DAN in the higher task load raised the question of compensation attempt versus less efficient use of neural resources in older adults. Lesser decrease of VAN activation with increasing load and decreased stimulus-driven activation in the VAN, especially in the higher load, in older participants suggested age-related reduced response in the VAN. However, functional connectivity measures showed that VAN was still functionally connected to the DAN in older participants. [less ▲]

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See detailSeasonal variation in human COGNITIVE brain responses
Meyer, Christelle; Muto, Vincenzo ULiege; Jaspar, Mathieu ULiege et al

Poster (2016, June)

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See detailThe impact of dopaminergic genes on inhibitory processes and cognitive control.
Jaspar, Mathieu ULiege; Muto, Vincenzo ULiege; Meyer, Christelle et al

Poster (2016, March 18)

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See detailModulating effect of COMT genotype on brain areas underlying cognitive control processes
Collette, Fabienne ULiege; Jaspar, Mathieu ULiege

Conference (2016, March 18)

Catechol-O-methyltransferase (COMT) is an important enzyme which degrades catecholamines, such dopamine, notably in the prefrontal cortex. A large number of studies reported an effect on executive ... [more ▼]

Catechol-O-methyltransferase (COMT) is an important enzyme which degrades catecholamines, such dopamine, notably in the prefrontal cortex. A large number of studies reported an effect on executive functioning of COMT genotype, each genotype being associated with a different COMT enzymatic activity. In this talk, I will present some of our studies that explored the neural substrates of inhibitory processes according to COMT genotype. These studies showed that COMT genotype modulates the brain-level implementation of proactive and reactive inhibitory control processes. We will discuss how individual differences related to DA-mediated signaling can differently influence inhibition in function of the form of cognitive control required by the task, but also regarding the specific inhibitory mechanism induced by the task. [less ▲]

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See detailSeasonality in human cognitive brain responses
Meyer, Christelle ULiege; Muto, Vincenzo ULiege; Jaspar, Mathieu ULiege et al

in Proceedings of the National Academy of Sciences of the United States of America (2016)

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See detailAutomatic artifacts and arousals detection in whole-night sleep EEG recordings
Coppieters't Wallant, Dorothe ULiege; Muto, Vincenzo ULiege; Gaggioni, Giulia ULiege et al

in Journal of Neuroscience Methods (2016), 258

In sleep electroencephalographic (EEG) signals, artifacts and arousals marking are usually part of the processing. This visual inspection by a human expert has two main drawbacks: it is very time ... [more ▼]

In sleep electroencephalographic (EEG) signals, artifacts and arousals marking are usually part of the processing. This visual inspection by a human expert has two main drawbacks: it is very time consuming and subjective. To detect artifacts and arousals in a reliable, systematic and reproducible automatic way, we developed an automatic detection based on time and frequency analysis with adapted thresholds derived from data themselves. The automatic detection performance is assessed using 5 statistic parameters, on 60 whole night sleep recordings coming from 35 healthy volunteers (male and female) aged between 19 and 26. The proposed approach proves its robustness against inter- and intra-, subjects and raters’ scorings, variability. The agreement with human raters is rated overall from substantial to excellent and provides a significantly more reliable method than between human raters. Existing methods detect only specific artifacts or only arousals, and/or these methods are validated on short episodes of sleep recordings, making it difficult to compare with our whole night results. The method works on a whole night recording and is fully automatic, reproducible, and reliable. Furthermore the implementation of the method will be made available online as open source code. [less ▲]

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See detailCircadian and homeostatic sleep pressure modulate fMRI correlates of vigilant attention
Muto, Vincenzo ULiege; Jaspar, Mathieu ULiege; Meyer, C et al

in Journal of Sleep Research (2016), 25(s1),

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See detailInfluence of COMT Genotype on Antero-Posterior Cortical Functional Connectivity Underlying Interference Resolution
Jaspar, Mathieu ULiege; Manard, Marine ULiege; DIDEBERG, Vinciane ULiege et al

in Cerebral Cortex (2016), 26

Genetic variability related to the catechol-O-methyltransferase (COMT) gene (Val158Met) has received increasing attention as a possible modulator of executive functioning and its neural correlates ... [more ▼]

Genetic variability related to the catechol-O-methyltransferase (COMT) gene (Val158Met) has received increasing attention as a possible modulator of executive functioning and its neural correlates. However, this attention has generally centred on the prefrontal cortices because of the well-known direct impact of COMT enzyme on these cerebral regions. In this study, we were interested in the modulating effect of COMT genotype on anterior and posterior brain areas underlying interference resolution during a Stroop task. More specifically, we were interested in the functional connectivity between the right inferior frontal operculum (IFop), an area frequently associated with inhibitory efficiency, and posterior brain regions involved in reading/naming processes (the two main non-executive determinants of the Stroop effect). The Stroop task was administered during fMRI scanning to three groups of 15 young adults divided according to their COMT Val158Met genotype [Val/Val (VV), Val/Met (VM) and Met/Met (MM)]. Results indicate greater activity in the right IFop and the left middle temporal gyrus (MTG) in homozygous VV individuals than in Met allele carriers. In addition, the VV group exhibited stronger positive functional connectivity between these two brain regions and stronger negative connectivity between the right IFop and left lingual gyrus. These results confirm the impact of COMT genotype on frontal function. They also strongly suggest that differences in frontal activity influence posterior brain regions related to a non-executive component of the task. Especially, changes in functional connectivity between anterior and posterior brain areas might correspond to compensatory processes for performing the task efficiently when the available dopamine level is low. [less ▲]

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See detailSeasonality in human cognitive brain responses.
Meyer, Christelle ULiege; Muto, Vincenzo ULiege; Jaspar, Mathieu ULiege et al

Poster (2015, September 04)

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See detailModulating effect of COMT Val158Met polymorphism on interference resolution during a working memory task
Jaspar, Mathieu ULiege; DIDEBERG, Vinciane ULiege; Bours, Vincent ULiege et al

in Brain & Cognition (2015), 95

Genetic variability related to the catechol-O-methyltransferase (COMT) gene has received increasing attention in the last 15 years, in particular as a potential modulator of the neural substrates ... [more ▼]

Genetic variability related to the catechol-O-methyltransferase (COMT) gene has received increasing attention in the last 15 years, in particular as a potential modulator of the neural substrates underlying inhibitory processes and updating in working memory (WM). In an event-related functional magnetic resonance imaging (fMRI) study, we administered a modified version of the Sternberg probe recency task (Sternberg, 1966) to 43 young healthy volunteers, varying the level of interference across successive items. The task was divided into two parts (high vs. low interference) to induce either proactive or reactive control processes. The participants were separated into three groups according to their COMT Val158Met genotype [Val/Val (VV); Val/Met (VM); Met/Met (MM)]. The general aim of the study was to determine whether COMT polymorphism has a modulating effect on the neural substrates of interference resolution during WM processing. Results indicate that interfering trials were associated with greater involvement of frontal cortices (bilateral medial frontal gyrus, left precentral and superior frontal gyri, right inferior frontal gyrus) in VV homozygous subjects (by comparison to Met allele carriers) only in the proactive condition of the task. In addition, analysis of peristimulus haemodynamic responses (PSTH) revealed that the genotype-related difference observed in the left SFG was specifically driven by a larger increase in activity from the storage to the recognition phase of the interfering trials in VV homozygous subjects. These results confirm the impact of COMT genotype on inhibitory processes during a WM task, with an advantage for Met allele carriers. Interestingly, this impact on frontal areas is present only when the level of interference is high, and especially during the transition from storage to recognition in the left superior frontal gyrus. [less ▲]

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See detailAutomatic artifact detection for whole-night polysomnographic sleep recordings
Coppieters't Wallant, Dorothe ULiege; Chellappa, Sarah Laxhmi ULiege; Gaggioni, Giulia ULiege et al

Poster (2014, September 17)

Detecting of bad channels and artifacts for whole-night polysomnographic recordings is very time consuming and tedious. We therefore developed an automatic procedure to automatize this job.

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See detailAutomatic biorythms description from actigraphic data
González y Viagas, Miguel ULiege; Ly, Julien ULiege; Gaggioni, Giulia ULiege et al

Poster (2014, September)

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See detailInfluence of noise correction on intra- and inter-subject variability of quantitative metrics in diffusion kurtosis imaging
André, Elodie ULiege; Grinberg, Farida; Farrher, Ezequiel et al

in PLoS ONE (2014)

Diffusion kurtosis imaging (DKI) is a promising extension of diffusion tensor imaging, giving new insights into the white matter microstructure and providing new biomarkers. Given the rapidly increasing ... [more ▼]

Diffusion kurtosis imaging (DKI) is a promising extension of diffusion tensor imaging, giving new insights into the white matter microstructure and providing new biomarkers. Given the rapidly increasing number of studies, DKI has a potential to establish itself as a valuable tool in brain diagnostics. However, to become a routine procedure, DKI still needs to be improved in terms of robustness, reliability, and reproducibility. As it requires acquisitions at higher diffusion31 weightings, results are more affected by noise than in diffusion tensor imaging. The lack of standard procedures for post-processing, especially for noise correction, might become a significant obstacle for the use of DKI in clinical routine limiting its application. We considered two noise correction schemes accounting for the noise properties of multichannel phased-array coils, in order to improve the data quality at signal-to-noise ratio (SNR) typical for DKI. The SNR dependence of estimated DKI metrics such as mean kurtosis (MK), mean diffusivity (MD) and fractional anisotropy (FA) is investigated for these noise correction approaches in Monte Carlo simulations and in in vivo human studies. The intra-subject reproducibility is investigated in a single subject study by varying the SNR level and SNR spatial distribution. Then the impact of the noise correction on inter-subject variability is evaluated in a homogeneous sample of 25 healthy volunteers. Results show a strong impact of noise correction on the MK estimate, while the estimation of FA and MD was affected to a lesser extent. Both intra- and inter-subject SNR related variability of the MK estimate is considerably reduced after correction for the noise bias, providing more accurate and reproducible measures. In this work, we have proposed a straightforward method that improves accuracy of DKI metrics. This should contribute to standardization of DKI applications in clinical studies and making valuable inferences in group analysis and longitudinal studies. [less ▲]

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