References of "Cremers, Julien"
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See detailImpaired automatic and unconscious motor processes in Parkinson's disease
D'Ostilio, Kevin ULg; CREMERS, Julien ULg; DELVAUX, Valérie ULg et al

in Scientific Reports (2013)

While it is increasingly recognized that voluntary movements are produced by an interaction between conscious and unconscious processes, the role of the latter in Parkinson’s disease has received little ... [more ▼]

While it is increasingly recognized that voluntary movements are produced by an interaction between conscious and unconscious processes, the role of the latter in Parkinson’s disease has received little attention to date. Here, we administered a subliminal masked prime task to 15 Parkinson’s disease patients and 15 age-matched healthy elderly subjects. Compatibility effects were examined by manipulating the direction of the arrows and the interstimuli interval. Analysis of the positive compatibility effect revealed performance differences between the most and the least affected hand in Parkinson’s disease patients. Additionally, patients did not show the same tendency toward a negative compatibility effect as compared to elderly controls. These novel findings provide evidence supporting the role of basal ganglia circuits in controlling the balance between automatic motor response facilitation and inhibition. [less ▲]

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See detailLes troubles du contrôle des impulsions associés au traitement dopaminergique substitutif antiparkinsonien
DEPIERREUX, Frédérique ULg; CREMERS, Julien ULg; SKAWINIAK, Eva ULg et al

in Revue Médicale de Liège (2013), 68(mai-juin), 221-225

Summary : In some patients, impulse control behaviours can be triggered by dopaminergic replacement therapy, particularly dopamine agonist drugs: hobbyism, punding (stereotyped behaviours), compulsive ... [more ▼]

Summary : In some patients, impulse control behaviours can be triggered by dopaminergic replacement therapy, particularly dopamine agonist drugs: hobbyism, punding (stereotyped behaviours), compulsive buying, binge eating disorder, pathological gamgling, hypersexuality, hedonistic homeostatic dysregulation syndrome ... The pathogenesis of these behaviours is not well understood, but likely involves aberrant changes in the dopaminergic pathways that mediate motivation i.e., a dopaminergic “overdose” in meso-cortico-limbic circuits. An early diagnosis is difficult, but mandatory to prevent the occurrence of devastating familial, marital, professional, socio-economic, medical and medico-legal consequences. Their management is not yet well standardized. Patients and caregivers should be warned about impulse control behaviours before starting dopamine agonists and monitoring for such behaviours while on therapy is requested. [less ▲]

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See detailLocalizing and comparing weight maps generated from linear kernel machine learning models
Schrouff, Jessica ULg; CREMERS, Julien ULg; GARRAUX, Gaëtan ULg et al

in 2013 Third International Workshop on Pattern Recognition in NeuroImaging (PRNI 2013): proceedings (2013)

Recently, machine learning models have been applied to neuroimaging data, allowing to make predictions about a variable of interest based on the pattern of activation or anatomy over a set of voxels ... [more ▼]

Recently, machine learning models have been applied to neuroimaging data, allowing to make predictions about a variable of interest based on the pattern of activation or anatomy over a set of voxels. These pattern recognition based methods present undeniable assets over classical (univariate) techniques, by providing predictions for unseen data, as well as the weights of each voxel in the model. However, the obtained weight map cannot be thresholded to perform regionally specific inference, leading to a difficult localization of the variable of interest. In this work, we provide local averages of the weights according to regions defined by anatomical or functional atlases (e.g. Brodmann atlas). These averages can then be ranked, thereby providing a sorted list of regions that can be (to a certain extent) compared with univariate results. Furthermore, we defined a “ranking distance”, allowing for the quantitative comparison between localized patterns. These concepts are illustrated with two datasets. [less ▲]

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See detailPreserved automatic inhibition effect after 1 Hz repetitive transcranial magnetic stimulation over the supplementary motor area
D'Ostilio, Kevin ULg; CREMERS, Julien ULg; DELVAUX, Valérie ULg et al

Poster (2013)

Background: It is widely accepted that medial frontal regions are involved in voluntary action control. Indeed, Sumner et al. (2007) have recently suggested that one of the mechanisms through which the ... [more ▼]

Background: It is widely accepted that medial frontal regions are involved in voluntary action control. Indeed, Sumner et al. (2007) have recently suggested that one of the mechanisms through which the supplementary motor area (SMA) contributes to voluntary control is automatic and unconscious motor inhibition. In this study, they administered a visuo-motor subliminal masked prime task (Eimer & Schlaghecken, 2003) to two patients with micro-lesions of the SMA and demonstrated an absence of automatic and unconscious inhibition as evoked by masked prime stimuli. This finding has been supported by neuroimaging data (D'Ostilio et al., 2012). Here, the aim of our research was to corroborate this result by means of a “virtual lesion” approach. Methods: For this purpose, we examined the effects of 1 Hz rTMS (train of 20 min; stimulus intensity 120 % of resting motor threshold) over the SMA of ten healthy volunteers, previously localized by functional magnetic resonance imaging (fMRI), on reaction time (RT) performance in the subliminal masked prime task. The functional localizer experiment consisted of four blocks of sequential finger tapping and 15 s of rest after each block. Imaging data were analyzed with SPM 8 and then were imported into the Brainsight software version 2.1.5. With such system, we were able to navigate across the subjects’ brain. The peak voxel in the SMA for each subject (at a statistical threshold of p < 0.05 uncorrected) was used as a target point for the rTMS session. Results: The mean motor threshold was 50.9 % of maximal stimulator output (SD: ± 4.86 %). Wilcoxon tests showed a significant effect of compatibility on RTs (sham: Z = 2.7, p = 0.007; rTMS: Z = 2.8, p = 0.005) and accuracy rate (sham: Z = 2.5, p = 0.01; rTMS: Z = 2.1, p = 0.03), subjects being slower and making more errors in compatible trials (sham: 391.64 ± 52 ms, 87.3 % of accuracy; rTMS: 396.66 ± 37 ms, 86.3 % of accuracy) in comparison to incompatible trials (sham: 357.45 ± 36 ms, 92.5 % of accuracy; rTMS: 356.25 ± 28 ms, 92.7 % of accuracy), suggesting motor inhibition. However, this NCE was preserved after rTMS over the SMA (RTs: Z = 0.87, p = 0.39; accuracy rate: Z = 0.71, p = 0.47). Conclusions: We conclude that long trains of low intensity 1 Hz rTMS did not affect the modulation of RT by subliminal stimuli, suggesting that the SMA might not be mandatory for the implementation of this automatic process. The limitation of this study is relative to the neural efficacy argument because we are not sure that TMS was strong enough to disturb the redundant organizational processing in the SMA or that other regions were not able to compensate for the virtually lesioned area. [less ▲]

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See detailDiscriminant BOLD Activation Patterns during Mental Imagery in Parkinson’s Disease
Schrouff, Jessica ULg; Cremers, Julien ULg; D'Ostilio, Kevin ULg et al

in Proceedings of MLINI 2012 (2012, December 07)

Using machine learning based models in clinical applications has become current practice and can prove useful to provide information at the subject’s level, such as predicting an (early) diagnosis or ... [more ▼]

Using machine learning based models in clinical applications has become current practice and can prove useful to provide information at the subject’s level, such as predicting an (early) diagnosis or monitoring the evolution of a disease. However, the performance of these models depends on the choice of a biomarker to detect the presence or absence of a disease. Choosing a biomarker is not straightforward, especially in the case of Parkinson’s disease when compared to healthy subjects. In the present work, we investigated the mental imagery of gait as a biomarker of Parkinson’s disease and showed that the signal in the mesencephalic locomotor region during the mental imagery of gait at a comfortable pace can discriminate significantly between idiopathic Parkinson’s disease patients and healthy subjects. Although there is room for improvement, the results of this preliminary study are promising. [less ▲]

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See detailNEURAL CORRELATES OF GAIT HYPOKINESIA IN PARKINSON'S DISEASE: AN FMRI STUDY
Cremers, Julien ULg; Stamatakis, Julien; D'Ostilio, Kevin ULg et al

Poster (2012, May 05)

Introduction: Brisk walking (BW) is an efficient tool to study gait hypokinesia whose pathogenesis remains poorly understood in Parkinson's disease (PD). Aims: Assuming that brain regions recruited during ... [more ▼]

Introduction: Brisk walking (BW) is an efficient tool to study gait hypokinesia whose pathogenesis remains poorly understood in Parkinson's disease (PD). Aims: Assuming that brain regions recruited during imagined gait strongly overlap with those recruited during real gait, we used mental imagery of BW as a paradigm to study the neural correlates of gait hypokinesia in PD with BOLD fMRI. Methods: 15 'on-drugs' PD patients and 15 controls matched for age and gender were instructed to imagine themselves in two situations: comfortable walking (CW) and BW on a 25 meter-path. Imagined speed reserve (ISR), defined as the difference between imagined BW and CW speeds, was measured as a control of behavioral performance. The first-level individual contrast images representing the comparison between BW and CW were entered into second-level analyses with the corresponding ISRs as correlation regressors. Results: ISRs and their real counterparts measured offline were significantly decreased in patients relatively to controls. They strongly positively correlated in patients (Pearson's r = 0.88) and controls (Pearson's r = 0.59). Between-group comparison of individual contrasts BW minus CW in correlation with their corresponding ISRs showed that increasing imagined gait speed was strongly associated with increased activity of the left posterior parietal cortex (PPC) in controls and with decreased activity of this region in the patients. Conclusions: Our findings suggest that gait hypokinesia is related to an impaired function of the left PPC in PD. The left PPC may represent a target for therapeutic interventions aimed at alleviating gait disturbances in PD. [less ▲]

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See detailEtude IRM par tenseur de diffusion (DTI) des anomalies microstructurelles de la matière blanche dans la maladie de Parkinson
Coolen, Tim; Cremers, Julien ULg; André, Elodie ULg et al

Poster (2012, March 21)

Introduction L’imagerie par résonance magnétique (IRM) conventionnelle du cerveau est réputée normale dans la maladie de Parkinson (MP), mais l’essor récent de techniques avancées offre de nouvelles ... [more ▼]

Introduction L’imagerie par résonance magnétique (IRM) conventionnelle du cerveau est réputée normale dans la maladie de Parkinson (MP), mais l’essor récent de techniques avancées offre de nouvelles perspectives, notamment l’IRM par tenseur de diffusion (DTI). Les études précédentes en la matière, hétérogènes dans leurs méthodes, montrent des résultats discordants. Ici, nous avons utilisé la DTI pour rechercher, sans hypothèse a priori, la présence d’anomalies microstructurelles au sein des principaux tracti de matière blanche dans la MP. Méthodes Soixante et un volumes en pondération de diffusion ont été acquis avec un système Allegra 3T (Siemens, Erlangen, Allemagne) au moyen d’une séquence DTI doublement refocalisée (1) chez 27 patients parkinsoniens non déments (durée moyenne d’évolution après le diagnostic : 5 ± 4.2 ans) et 25 contrôles d’âge (MP: 68,7±8,4; C: 65,1±8,8) et de genre similaires. Pour chaque sujet, les valeurs d’anisotropie fractionnelle (FA) et de diffusivité moyenne (MD) ont été extraites à partir d’un modèle du tenseur obtenu au moyen du logiciel ExploreDTI (2) faisant appel à la méthode RESTORE (3). Nous avons ensuite utilisé le module TBSS (v1.2) du logiciel FSL (4) pour conformer les images des scalaires dans un espace tridimensionnel commun puis rechercher, voxel-par-voxel, des différences entre les 2 groupes au sein du squelette de la matière blanche. Les résultats obtenus à l’issue d’un test par permutations (N=10000) ont été corrigés pour des comparaisons multiples. Résultats L’analyse des cartes de FA montre des valeurs significativement (P<0.05) plus élevées chez les patients dans plusieurs régions (5): fibres sous-corticales péri-rolandiques droites, parties du faisceau arqué droit, fibres du faisceau longitudinal inférieur et /ou fronto-occipital inférieur droit, fibres sous-corticales préfrontales gauches, partie postérieure du genou corps calleux. La comparaison inverse ne révèle aucun résultat significatif ni l’analyse des cartes de MD. Conclusions Ces résultats sont en accord avec les modèles physiopathologiques selon lesquels le primum movens dans la MP se situe dans une dysfonction synaptique et axonale (6,7). Une augmentation des valeurs de FA de la matière blanche dans la MP est en contradiction avec la plupart mais pas toutes (8,9) les études précédentes. L’hypothèse d’une diminution relative des fibres de croisement dans ces régions chez les patients mérite d’être testée au moyen de méthodes d’acquisition et d’analyse plus élaborées. Références 1. Nagy Z, et al. Magn Reson Med 2008; 60(5):1256-1260. 2. Leemans A, et al. Proc Intl Soc Mag Reson Med 17 2009;3537. (Abstract). 3. Chang LC, et al. Magn Reson Med 2005;3(5):1088-1095. 4. Smith SM et al. Neuroimage 2006; 31(4):1487-1505. 5. Catani M, et al. Cortex 2008; 44(8):1105-1132. 6. Schulz-Schaeffer WJ. Acta Neuropathol 2010; 120(2):131-143. 7. Cheng HC, et al. Ann Neurol 2010; 67(6):715-725. 8. Tessa C, et al. AJNR 2008; 29(4):674-680. 9. Wang JJ et al. Radiology 2011; 261(1):210-217. Remerciements Ce travail est financé par le Fonds de la Recherche Scientifique (FNRS-FRS) de la Communauté Française de Belgique. [less ▲]

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See detailBrain activation pattern related to gait disturbances in Parkinson's disease.
Cremers, Julien ULg; D'Ostilio, Kevin ULg; Stamatakis, Julien et al

in Movement Disorders : Official Journal of the Movement Disorder Society (2012), 27(12), 1498-505

Gait disturbances represent a therapeutic challenge in Parkinson's disease (PD). To further investigate their underlying pathophysiological mechanisms, we compared brain activation related to mental ... [more ▼]

Gait disturbances represent a therapeutic challenge in Parkinson's disease (PD). To further investigate their underlying pathophysiological mechanisms, we compared brain activation related to mental imagery of gait between 15 PD patients and 15 age-matched controls using a block-design functional MRI experiment. On average, patients showed altered locomotion relatively to controls, as assessed with a standardized gait test that evaluated the severity of PD-related gait disturbances on a 25-m path. The experiment was conducted in the subjects as they rehearsed themselves walking on the same path with a gait pattern similar as that during locomotor evaluation. Imagined walking times were measured on a trial-by-trial basis as a control of behavioral performance. In both groups, mean imagined walking time was not significantly different from that measured during real gait on the path used for evaluation. The between-group comparison of the mental gait activation pattern with reference to mental imagery of standing showed hypoactivations within parieto-occipital regions, along with the left hippocampus, midline/lateral cerebellum, and presumed pedunculopontine nucleus/mesencephalic locomotor area, in patients. More specifically, the activation level of the right posterior parietal cortex located within the impaired gait-related cognitive network decreased proportionally with the severity of gait disturbances scored on the path used for gait evaluation and mental imagery. These novel findings suggest that the right posterior parietal cortex dysfunction is strongly related to the severity of gait disturbances in PD. This region may represent a target for the development of therapeutic interventions for PD-related gait disturbances. (c) 2012 Movement Disorder Society. [less ▲]

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See detailNeural correlates of hypokinetic gait in Parkinson’s disease: An fMRI study
Cremers, Julien ULg; Stamatakis, Julien; D'Ostilio, Kevin ULg et al

Poster (2012)

Objective: To investigate the neural correlates of hypokinetic gait in Parkinson’s disease (PD) using functional magnetic resonance imaging (fMRI). Background: Although hypokinetic gait is frequent and ... [more ▼]

Objective: To investigate the neural correlates of hypokinetic gait in Parkinson’s disease (PD) using functional magnetic resonance imaging (fMRI). Background: Although hypokinetic gait is frequent and has a negative impact on quality of life in PD, its underlying mechanisms remain poorly understood. Assuming that the brain regions recruited during real and imagined gait strongly overlap, mental imagery of brisk gait may be a successful approach to study hypokinetic gait in PD. Methods: Fifteen ‘‘on-drugs’’ PD patients (8 males; mean age 5 65.1 6 9.4 years) and fifteen controls matched for age, gender and mental imagery skills were trained to perform video-taped trials of comfortable and brisk gait on a 25 meter-path. The study was organ- ized as a block-design fMRI experiment where subjects were instructed to rehearse themselves performing comfortable and brisk gait and to press a key to indicate when they completed each 25 meter-imagined gait trial. The imagined speed reserve (ISR) defined as the difference between imagined brisk and comfortable gait speeds was measured as a control of behavioral performance. Imaging data processing and analyses were performed using SPM8. The first-level individual contrast images representing the comparison between brisk and comfortable gait were entered as two separate groups (controls vs patients) in an ANOVA with the corresponding ISRs as correlation regressors. Results: Compared with controls, patients showed hypokinetic gait during real gait training as their increase in speed during brisk relatively to comfortable gait was related to an increase in step ca- dence (r50.87; p<0.001) but not in step length (r50.11). ISRs meas- ured during fMRI and their real counterparts measured offline strongly correlated in patients (r50.88; p<0.001) and controls (r50.59; p50.02). Between-group comparison (p<0.001, uncorrected) of fMRI data showed that increasing imagined gait speed was strongly associated with increased activity of the left posterior parietal cortex in controls and with decreased activity of this region in patients. Conclusions: Our findings suggest that hypokinetic gait in PD is related to the impaired functioning of the left posterior parietal cortex. This area may represent a target for therapeutic interventions aimed at alleviating gait disturbances in PD. [less ▲]

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See detailConstruction and validation of the Dynamic Parkinson Gait Scale (DYPAGS).
Cremers, Julien ULg; PHAN BA, Remy ULg; DELVAUX, Valérie ULg et al

in Parkinsonism & Related Disorders (2012)

The dynamic evaluation of Parkinson's disease (PD)-related episodic gait disturbances in routine is challenging. Therefore, the aim of our study was to assess the reliability/validity of the Dynamic ... [more ▼]

The dynamic evaluation of Parkinson's disease (PD)-related episodic gait disturbances in routine is challenging. Therefore, the aim of our study was to assess the reliability/validity of the Dynamic Parkinson Gait Scale (DYPAGS) composed of eight relevant items for the objective quantification of PD gait features: walking forwards/backwards/with dual-task, turning to both sides, imaginary obstacle avoidance with both legs and passing through narrow spaces. The scale was validated on thirty-five patients with mild to severe parkinsonism in their habitual "on-state". A shorter 6 item-version was designed on the basis of a principal component analysis. No significant floor/ceiling effect was detected. The internal consistency was excellent. The levels of interrater agreement, precision and minimal detectable change were adequate. The criterion-related validity was demonstrated by strong correlations with the DYPAGS scores and those at the gait subscales of the Tinetti Mobility Test and MDS-UPDRS. The construct validity was assessed by moderate-strong correlations with the Freezing of Gait Questionnaire, mobility index of the PD Questionnaire (PDQ-39), disease duration and levodopa equivalent daily doses. Statistical analyses using the coefficient of determination showed that both DYPGAS versions were superior to the other instruments to identify patients with gait disturbances with poorer response to dopaminergic treatment. Full and short DYPAGS are reliable instruments for the quantification of "on" PD-related episodic gait disturbances. The full version is sensitive to detect subtle disturbances in mild parkinsonism. The shorter one is easily administered and reliably quantifies gait disturbances in moderate to severe parkinsonism. We recommend their use for research and clinical practice. [less ▲]

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See detailEffects of light deprivation on visual evoked potentials in migraine without aura.
Coppola, Gianluca; Cremers, Julien ULg; GERARD, Pascale ULg et al

in BMC Neurology (2011), 11

BACKGROUND: The mechanisms underlying the interictal habituation deficit of cortical visual evoked potentials (VEP) in migraine are not well understood. Abnormal long-term functional plasticity of the ... [more ▼]

BACKGROUND: The mechanisms underlying the interictal habituation deficit of cortical visual evoked potentials (VEP) in migraine are not well understood. Abnormal long-term functional plasticity of the visual cortex may play a role and it can be assessed experimentally by light deprivation (LD). METHODS: We have compared the effects of LD on VEP in migraine patients without aura between attacks (MO, n = 17) and in healthy volunteers (HV, n = 17). Six sequential blocks of 100 averaged VEP at 3.1 Hz were recorded before and after 1 hour of LD. We measured VEP P100 amplitude of the 1st block of 100 sweeps and its change over 5 sequential blocks of 100 responses. RESULTS: In HV, the consequence of LD was a reduction of 1st block VEP amplitude and of the normal habituation pattern. By contrast, in MO patients, the interictal habituation deficit was not significantly modified, although 1st block VEP amplitude, already lower than in HV before LD, further decreased after LD. CONCLUSIONS: Light deprivation is thought to decrease both excitatory and subsequent inhibitory processes in visual cortex, which is in line with our findings in healthy volunteers. The VEP results in migraine patients suggest that early excitation was adequately suppressed, but not the inhibitory mechanisms occurring during long term stimulation and habituation. Accordingly, deficient intracortical inhibition is unlikely to be a primary factor in migraine pathophysiology and the habituation deficit. [less ▲]

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See detailGait feature extraction in Parkinson's disease using low-cost accelerometers
Stamatakis, Julien; Cremers, Julien ULg; Maquet, Didier ULg et al

Poster (2011)

The clinical hallmarks of Parkinson’s disease (PD) are movement poverty and slowness (i.e. bradykinesia), muscle rigidity, limb tremor or gait disturbances. Parkinson’s gait include slowness, shuffling ... [more ▼]

The clinical hallmarks of Parkinson’s disease (PD) are movement poverty and slowness (i.e. bradykinesia), muscle rigidity, limb tremor or gait disturbances. Parkinson’s gait include slowness, shuffling, short steps, freezing of gait (FoG) and/or asymmetries in gait. There are currently no validated clinical instruments or device that allow a full characterization of gait disturbances in PD. As a step towards this goal, a four accelerometer-based system is proposed to increase the number of parameters that can be extracted to characterize parkinsonian gait disturbances such as FoG or gait asymmetries. After developing the hardware, an algorithm has been developed, that automatically epoched the signals on a stride-by-stride basis and quantified, among others, the gait velocity, the stride time,the stance and swing phases, the single and double support phases or the maximum acceleration at toe-off, as validated by visual inspection of video recordings during the task. The results obtained in a PD patient and an healthy volunteer are presented. The FoG detection will be improved using time-frequency analysis and the system is about to be validated with a state-of-the-art 3D movement analysis system. [less ▲]

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See detailHemispheric specialization during mental imagery of brisk walking.
Cremers, Julien ULg; Dessoullieres, Aurélie; Garraux, Gaëtan ULg

in Human Brain Mapping (2011)

OBJECTIVES: Brisk walking, a sensitive test to evaluate gait capacity in normal and pathological aging such as parkinsonism, is used as an alternative to classical fitness program for motor rehabilitation ... [more ▼]

OBJECTIVES: Brisk walking, a sensitive test to evaluate gait capacity in normal and pathological aging such as parkinsonism, is used as an alternative to classical fitness program for motor rehabilitation and may help to decrease the risk of cognitive deterioration observed with aging. In this study, we aimed to identify brain areas normally involved in its control. METHODS: We conducted a block-design blood oxygen level dependent function magnetic resonance imaging (BOLD fMRI) experiment in 18 young healthy individuals trained to imagine themselves in three main situations: brisk walking in a 25-m-long corridor, standing or lying. Imagined walking time (IWT) was measured as a control of behavioral performance during fMRI. RESULTS: The group mean IWT was not significantly different from the actual walking time measured during a training session prior to the fMRI study. Compared with other experimental conditions, mental imagery (MI) of brisk walking was associated with stronger activity in frontal and parietal regions mainly on the right, and cerebellar hemispheres, mainly on the left. Presumed imagined walking speed (2.3 +/- 0.4 m/s) was positively correlated with activity levels in the right dorsolateral prefrontal cortex and posterior parietal lobule along with the vermis and the left cerebellar hemisphere. INTERPRETATIONS: A new finding in this study is that MI of brisk walking in young healthy individuals strongly involves processes lateralized in right fronto-parietal regions along with left cerebellum. These results show that brisk walking might be a non automatic locomotor activity requiring a high-level supraspinal control. Hum Brain Mapp, 2011. (c) 2011 Wiley-Liss, Inc. [less ▲]

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See detailFinger Tapping feature extraction in Parkinson's disease using low-cost accelerometers
Stamatakis, Julien; Cremers, Julien ULg; Macq, Benoït et al

in Proceedings 10th IEEE International Conference on Information Technology and Applications in Biomedicine (ITAB 2010) (2010)

The clinical hallmarks of Parkinson's disease (PD) are movement poverty and slowness (i.e. bradykinesia), muscle rigidity and limb tremor. The physicians usually quantify these motor disturbances by ... [more ▼]

The clinical hallmarks of Parkinson's disease (PD) are movement poverty and slowness (i.e. bradykinesia), muscle rigidity and limb tremor. The physicians usually quantify these motor disturbances by assigning a severity score according to validated but time-consuming clinical scales such as the Unified Parkinson's Disease Rating Scale (UPDRS) - part III. These clinical ratings are however prone to subjectivity and inter-rater variability. The PD medical community is therefore looking for a faster and more objective rating method. As a first step towards this goal, a tri-axial accelerometer-based system is proposed as patients are engaged in a repetitive finger tapping task, which is classically used to assess bradykinesia in the UPDRS-III. After developing the hardware, an algorithm has been developed, that automatically epoched the signal on a trial-by-trial basis and quantified, among others, movement speed, amplitude, hesitations or halts as validated by visual inspection of video recordings during the task. The results obtained in a PD patient and an healthy volunteer are presented. Preliminary results show that PD patients and healthy volunteers have different features profiles, so that a classifier could be set up to predict objective UPDRS-III scores. [less ▲]

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See detailUnified Freezing of Gait Rating Scale (UFOGS)
Cremers, Julien ULg; Garraux, Gaëtan ULg

in Movement Disorders : Official Journal of the Movement Disorder Society (2009), 24(Suppl. 1), 432-433

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See detailEvidence for increased upper brain stem activity following STN-DBS in Parkinson's disease: An (18)FDG-PET study
Desoullieres, Aurélie; KASCHTEN, Bruno ULg; CREMERS, Julien ULg et al

in Movement Disorders : Official Journal of the Movement Disorder Society (2009), 24(Suppl. 1), 186-187

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See detailLe cas clinique du mois. Le syndrome lissencephalique de Miller-Dieker.
Cremers, Julien ULg; Scholsem, Martin; Scholtes, Félix ULg et al

in Revue Médicale de Liège (2007), 62(3), 139-43

We present the case of a 10-year-old boy who presents with a severe epilepsy resistant to medical treatment in the context of a Miller-Dieker syndrome. This patient underwent the implantation of a ... [more ▼]

We present the case of a 10-year-old boy who presents with a severe epilepsy resistant to medical treatment in the context of a Miller-Dieker syndrome. This patient underwent the implantation of a pneumogastric nerve stimulator. We describe the patient's clinical history and the main characteristics of lissencephaly syndrome. [less ▲]

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See detailMigraine with Urticaria
Fumal, Arnaud ULg; Cremers, Julien ULg; Ambrosini, A. et al

in Neurology (2006), 67(4), 682

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