References of "GARRAUX, Gaëtan"
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See detailA Novel Accelerometer-Based Method for Stride Length Estimation
Boutaayamou, Mohamed ULiege; Schwartz, Cédric ULiege; Denoël, Vincent ULiege et al

Poster (2017, July 14)

We demonstrate the feasibility of accurately and precisely estimating the left/right average stride length from measured heel/toe accelerations in the gait of healthy, old adults. Our approach relies on ... [more ▼]

We demonstrate the feasibility of accurately and precisely estimating the left/right average stride length from measured heel/toe accelerations in the gait of healthy, old adults. Our approach relies on (1) a novel method that uses only accelerometer data without the need of additional data from, e.g., gyroscopes and/or magnetometers, and on (2) the validation of the results using reference 3D optoelectronic system data. [less ▲]

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See detailMean and variance of Dynamic Functional Connectivity in Parkinson’s Disease
Baquero Duarte, Katherine Andrea ULiege; Guldenmund, Pieter; Rouillard, Maud ULiege et al

Poster (2017, June 29)

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See detailComparative assessment of 6-[18F]fluoro-L-m-tyrosine and 6-[18F]fluoro-L-dopa to evaluate dopaminergic presynaptic integrity in a Parkinson’s disease rat model.
Becker, Guillaume ULiege; Bahri, Mohamed Ali ULiege; Michel, Anne et al

in Journal of Neurochemistry (2017), 141

Because of the progressive loss of nigro-striatal dopaminergic terminals in Parkinson’s disease (PD), in vivo quantitative imaging of dopamine (DA) containing neurons in animal models of PD is of critical ... [more ▼]

Because of the progressive loss of nigro-striatal dopaminergic terminals in Parkinson’s disease (PD), in vivo quantitative imaging of dopamine (DA) containing neurons in animal models of PD is of critical importance in the pre-clinical evaluation of highly awaited disease-modifying therapies. Among existing methods, the high sensitivity of positron emission tomography (PET) is attractive to achieve that goal. The aim of this study was to perform a quantitative comparison of brain images obtained in 6-hydroxydopamine (6-OHDA) lesioned rats using two dopaminergic PET radiotracers, namely [18F]fluoro-3,4-dihydroxyphenyl-L-alanine ([18F]FDOPA) and 6-[18F]fluoro-L-m-tyrosine ([18F]FMT). Because the imaging signal is theoretically less contaminated by metabolites, we hypothesized that the latter would show stronger relationship with behavioural and post-mortem measures of striatal dopaminergic deficiency. We used a within-subject design to measure striatal [18F]FMT and [18F]FDOPA uptake in eight partially lesioned, eight fully lesioned and ten sham-treated rats. Animals were pretreated with an L-aromatic amino acid decarboxylase (AADC) inhibitor. A catechol-O-methyl transferase inhibitor was also given before [18F]FDOPA PET. Quantitative estimates of striatal uptake were computed using conventional graphical Patlak method. Striatal dopaminergic deficiencies were measured with apomorphine-induced rotations and post-mortem striatal DA content. We observed a strong relationship between [18F]FMT and [18F]FDOPA estimates of decreased uptake in the denervated striatum using the tissue-derived uptake rate constant Kc. However, only [18F]FMT Kc succeeded to discriminate between the partial and the full 6-OHDA lesion and correlated well with the post-mortem striatal DA content. This study indicates that the [18F]FMT could be more sensitive, with respect of [18F]FDOPA, to investigate DA terminals loss in 6-OHDA rats, and open the way to in vivo AADC activity targeting in future investigations on progressive PD models. [less ▲]

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See detailAmbulatory System for Gait Analysis
Boutaayamou, Mohamed ULiege; Bruls, Olivier ULiege; Croisier, Jean-Louis ULiege et al

Conference (2017, April 29)

We describe the principle and use of a wireless, 3-axis accelerometer-based ambulatory system that records acceleration signals and automatically analyses them to characterize normal and pathological gait ... [more ▼]

We describe the principle and use of a wireless, 3-axis accelerometer-based ambulatory system that records acceleration signals and automatically analyses them to characterize normal and pathological gait. The associated algorithm is versatile enough to detect, on a stride-by-stride basis, refined gait parameters that quantify subtle gait disturbances in, e.g., in Parkinson’s disease in a rater-independent way. The experimental results show the potential of the developed accelerometer-based technique to be used in neurology (e.g., characterization of Parkinsonian gait: slowness, shuffling, short steps, freezing of gait, asymmetries in gait), rehabilitation, geriatrics (ex. monitoring activity parameters in the elderly), orthopedics and sport. [less ▲]

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See detailMultivariate analysis of 18F-DMFP PET data to assist the diagnosis of parkinsonism
Segovia, Fermin; Gorriz, Juan M.; Ramirez, Javier et al

in Frontiers in Neuroinformatics (2017)

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See detailAlgorithm for Temporal Gait Analysis Using Wireless Foot-Mounted Accelerometers
Boutaayamou, Mohamed ULiege; Denoël, Vincent ULiege; Bruls, Olivier ULiege et al

Book published by Springer (2017)

We present a new signal processing algorithm that extracts five gait events: heel strike, toe strike, heel-off, toe-off, and heel clearance from only two accelerometers attached on the heels of the ... [more ▼]

We present a new signal processing algorithm that extracts five gait events: heel strike, toe strike, heel-off, toe-off, and heel clearance from only two accelerometers attached on the heels of the subjects usual shoes. This algorithm first uses a continuous wavelet-based segmentation that parses the signal of consecutive strides into motionless periods defining relevant local acceleration signals. Then, the algorithm uses versatile techniques to accurately extract the five gait events from these local acceleration signals. We validated, on a stride-by-stride basis, the extraction of these gait events by comparing the results with reference data provided by a kinematic 3D analysis system and a video camera. The accuracy and precision achieved by the extraction algorithm for healthy subjects, the reduced number of accelerometer units required, and the validation results obtained, encourage us to further study this system in pathological conditions. [less ▲]

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See detailGait pattern of healthy old people for fast walking condition
GILLAIN, Sophie ULiege; Boutaayamou, Mohamed ULiege; Schwartz, Cédric ULiege et al

in Gerontechnology (2016, September)

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See detailGait pattern of healthy old people for dual task walking condition
GILLAIN, Sophie ULiege; Boutaayamou, Mohamed ULiege; Schwartz, Cédric ULiege et al

in Gerontechnology (2016, September)

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See detailIn vivo quantification of dopaminergic terminals loss in Parkinson’s Disease rat model: comparison between [18F]FMT and [18F]FDOPA.
Becker, Guillaume ULiege; Bahri, Mohamed Ali ULiege; Michel, Anne et al

in Molecular Imaging & Biology (2016, July), 18(S1), 1744

Objectives: Rat models of Parkinson’s disease (PD), such as unilaterally lesioned rats with 6-hydroxydopamine (6-OHDA), are useful to evaluate novel antiparkinsonian therapies. MicroPET imaging, using L-3 ... [more ▼]

Objectives: Rat models of Parkinson’s disease (PD), such as unilaterally lesioned rats with 6-hydroxydopamine (6-OHDA), are useful to evaluate novel antiparkinsonian therapies. MicroPET imaging, using L-3,4-dihydroxy-6-[18F]-fluoro-phenylalanine ([18F]FDOPA) allows longitudinal evaluations of DA terminals loss. However, chemical structure of [18F]FDOPA leads to suboptimal PET imaging. 18F-fluoro-m-tyrosine ([18F]FMT) is an effective PET tracer to evaluate DA terminals integrity and L-aromatic amino acid decarboxylase (AAAD) metabolic pathway. So far, there are no available quantitative PET studies comparing the two methods in hemiparkinsonian rats. In this study, we compare imaging data provided by [18F]FMT PET and [18F]FDOPA PET in 6-OHDA-lesioned rats. Methods: 10 µg of 6-OHDA were injected into the right medial forebrain bundle (MFB) of male Sprague-Dawley rats (n=8). As control, sham-treated rats (n=8) were injected with vehicle only but otherwise treated identically. Striatal DA presynaptic activity was assessed by dynamic PET with both [18F]FMT and [18F]FDOPA. Structural T2-weighted brain images were acquired on a 9.4T MRI and were used for co-registration. After normalization on a MRI template, kinetic analysis was performed by “Patlak Reference” model, using PMOD software. Six days after the last PET scan, rats were sacrificed, and striatum were rapidly removed for striatal DA and metabolites quantification. Results: Striatal accumulation was observed for both tracers. However, while the administration of [18F]FDOPA required two peripheral inhibitors (benserazide and entacapone), only benserazide is needed with [18F]FMT. As consequence of the 6-OHDA-lesion, significant decrease of both [18F]FMT and [18F]DOPA accumulation was recorded in the striatum ipsilateral to the lesion. Lesioned rats had dramatically reduced uptake constant Ki in the ipsilateral striatum compared to the contralateral striatum (p<0.001 for [18F]FMT and p<0.05 for [18F]DOPA) and to the ipsilateral striatum of sham-treated rats (p<0.001 for both tracers). The DA content in the ipsilateral striatum was significantly lower (p<0.001) than in the contralateral striatum in the 6-OHDA-injected group, whereas such difference was not measured with the sham group. This indicate that [18F]FMT PET is as effective as [18F]DOPA PET to quantify loss of DA presynaptic function in unilaterally 6-OHDA lesioned rats. Conclusions: Our results are in agreement with data reporting correlation between these two tracers in a Non-human primate model of PD. The sensitivity of the data quantification obtained in this study, confirms the interest to pursue longitudinal investigations with [18F]FMT to monitor dopaminergic dysfunction in a more progressive preclinical model of PD. [less ▲]

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See detailAnalysis of temporal gait features extracted from accelerometer-based signals during ambulatory walking in Parkinson’s disease
Boutaayamou, Mohamed ULiege; Demonceau, Marie ULiege; Bruls, Olivier ULiege et al

Poster (2016, June 21)

Objective: To perform a proof-of-concept study showing the utility of versatile algorithms aimed at objectively quantifying the duration of refined gait features during ambulatory walking in a patient ... [more ▼]

Objective: To perform a proof-of-concept study showing the utility of versatile algorithms aimed at objectively quantifying the duration of refined gait features during ambulatory walking in a patient with Parkinson’s disease (PD) in ON and OFF medication states as compared with an age-matched control subject. [less ▲]

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See detailIn vivo quantification of dopaminergic terminals loss in Parkinson’s Disease rat with AAV-induced overexpression of alpha-synuclein: a [18F]FMT microPET study.
Becker, Guillaume ULiege; Bahri, Mohamed Ali ULiege; Michel, Anne et al

Poster (2016, March 08)

Objectives: Rat models of Parkinson’s disease (PD), such as progressive neurodegeneration induced by adeno-associated virus (AAV)-mediated over-expression of human -synuclein (A53T) in midbrain dopamine ... [more ▼]

Objectives: Rat models of Parkinson’s disease (PD), such as progressive neurodegeneration induced by adeno-associated virus (AAV)-mediated over-expression of human -synuclein (A53T) in midbrain dopamine neurons, are useful to evaluate novel antiparkinsonian therapies [1]. In vivo quantitative imaging of dopamine neurotransmission allows longitudinal evaluation of such PD’s rat model [2]. In this study, we investigate DA presynaptic function, with [18F]FMT PET (radiotracer of the L-aromatic amino acid decarboxylase enzyme), in the AAV A53T PD’s rat model, and correlate the results with behavioral measurements. Methods: All animals were injected with 2 µL A53T -synuclein (n=6) or GFP (n=2) AAV2/9 in the right substantia nigra. Striatal DA presynaptic activity was assessed by dynamic PET with [18F]FMT [3] at 18 weeks post-lesion. Kinetic analysis was performed by “Patlak Reference” model, using PMOD software. Rats were monitored for motor behavior and assessed before the lesion, and at 4, 12 and 18 weeks post-lesion. Results: As consequence of AAV-mediated A53T overexpression, significant decrease of [18F]FMT accumulation was recorded in the striatum ipsilateral to the lesion. Lesioned rats had dramatically reduced uptake constant Ki in the ipsilateral striatum compared to the contralateral striatum (p<0.001 for [18F]FMT) and to the ipsilateral striatum of sham-treated rats (p<0.001). Significant deficit in stepping adjustment was observed with the contralateral forepaw at 4, 12 and 18 weeks. Significant reduction of the time spent on the rotarod was also measured at 12 and 18 weeks. Conclusions: Our results report good correlations between [18F]FMT PET outcomes and behavioral results. The sensitivity of the data quantification obtained in this study, confirms the interest to pursue longitudinal investigations with [18F]FMT to monitor dopaminergic dysfunction in this progressive preclinical model of PD. [less ▲]

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See detailComment on: Hemidystonia caused by frontal cortical infarction.
Garraux, Gaëtan ULiege

in Acta Neurologica Belgica (2016), 116

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See detailContribution of four lifelong factors of cognitive reserve on late cognition in normal aging and Parkinson’s disease
Rouillard, Maud; Audiffren, Michel; Albinet, Cédric et al

in Journal of Clinical and Experimental Neuropsychology (2016)

Introduction. Cognitive reserve (CR) was proposed to explain how individual differences in brain function help to cope with the effects of normal aging and neurodegenerative diseases. Education ... [more ▼]

Introduction. Cognitive reserve (CR) was proposed to explain how individual differences in brain function help to cope with the effects of normal aging and neurodegenerative diseases. Education, professional solicitations, engagement in leisure and physical activities across the lifetime are considered as major determinants of this reserve. Method. Using multiple linear regression analyses, we tested separately in healthy elderly and Parkinson's disease (PD) populations to what extent cognitive performance in several domains was explained by (1) any of these four environmental lifespan variables ; (2) demographic and clinical variables (age, gender, depression score and, for the PD group, duration of disease and dopaminergic drugs). We also tested for an interaction, if any, between these lifespan variables and brain pathology indexed by global atrophy measured from high-resolution anatomical magnetic resonance imaging. Results. Age was negatively associated with cognitive performance in the PD group. In healthy elderly participants, we observed significant positive associations between cognitive performance and 1) education, 2) leisure activities, 3) professional solicitation (decisional latitude). Furthermore, participants with greater brain atrophy benefited more from CR. In PD patients, education and professional solicitations contributed to cognitive performance but to a lesser extent than in controls. CR factors modulated the relationship between cognition and brain atrophy only in patients with a slight or moderate brain atrophy. Conclusions. Education is the CR factor that contributed the most to late cognitive functioning in both groups, closely followed by leisure activity in normal aging and professional solicitations in PD. Our results also provide evidence suggesting that the effects of CR does not express similarly in normal aging and PD. From a broader perspective, these results seem to indicate that CR factors the most consistently practiced across lifespan (education and professional solicitation) are those that are the more strongly associated to late cognitive efficiency. [less ▲]

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See detailEffects of 10Hz and 20Hz transcranial alternating current stimulation on automatic motor control
Cappon, Davide; D'Ostilio, Kevin ULiege; Garraux, Gaëtan ULiege et al

in Brain Stimulation (2016)

Background: Automatic motor inhibition is an important and adaptive process through which an activated motor plan is suppressed if the movement is not intended to be executed. Neuronal networks are ... [more ▼]

Background: Automatic motor inhibition is an important and adaptive process through which an activated motor plan is suppressed if the movement is not intended to be executed. Neuronal networks are characterized by oscillatory activity. In the brain, a large variety of rhythms have been described that differ in their frequency, origin and reactivity to changes in task demands. Recent studies have demonstrated that active cortical networks are susceptible to weak sinusoidal perturbations of exogenous electric fields. Objective/Hypothesis: The aim of this study was to investigate the frequency-specific effect of transcranial alternate current stimulation (tACS) over the automatic control of movement in healthy volunteers. We hypothesized that applying two different tACS frequencies during a visuo-motor task would result in different behavioural effects and in diverse modulation of cortical excitability. Methods: In this study we used tACS to interact non-invasively with the ongoing task-related oscillatory activity. Stimulation was delivered at alpha (10 Hz) and beta (20 Hz) frequency over the supplementary motor area and the primary motor cortex (SMA-M1) connections, which are part of the BG-cortical motor loop, during the execution of the subliminal masked prime task. We measured the effects on task performance and on motor cortex corticospinal excitability by means of motor evoked potentials (MEPs) evoked by transcranial magnetic stimulation (TMS). Results: Results indicate a specific effect of 10 and 20-Hz tACS on functional inhibition in the SMA-M1 circuit. Behaviorally there is an interference in task-related automatic inhibition: 10 Hz tACS reduced the automatic inhibition. In contrast 20 Hz tACS increased the automatic inhibition. At a neurophysiological level there is a modulation in excitability of M1: 20 Hz tACS reduced MEP amplitudes, whereas there was no change after 10 Hz tACS. Conclusion(s): The current study provides novel evidence that automatic mechanisms of motor behaviour can be modulated by imposing synchronized electrical oscillatory activity upon motor cortical regions. Our study has important implications for cognitive neuroscience studies suggesting that the use tACS might offer the possibility to demonstrate a causal link between endogenous brain oscillations, specific exogenous alternate current frequencies and specific cognitive processes. [less ▲]

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See detailThe network model of depression as a basis for new therapeutic strategies for treating major depressive disorder in Parkinson’s disease
D'Ostilio, Kevin ULiege; Garraux, Gaëtan ULiege

in Frontiers in Human Neuroscience (2016), 10(161),

The high prevalence of major depressive disorder in people with Parkinson's disease, its negative impact on health-related quality of life and the low response rate to conventional pharmacological ... [more ▼]

The high prevalence of major depressive disorder in people with Parkinson's disease, its negative impact on health-related quality of life and the low response rate to conventional pharmacological therapies call to seek innovative treatments. Here, we review the new approaches for treating major depressive disorder in patients with Parkinson's disease within the framework of the network model of depression. According to this model, major depressive disorder reflects maladaptive neuronal plasticity. Non-invasive brain stimulation using high frequency repetitive transcranial magnetic stimulation over the prefrontal cortex has been proposed as a feasible and effective strategy with minimal risk. The neurobiological basis of its therapeutic effect may involve neuroplastic modifications in limbic and cognitive networks. However, the way this networks reorganize might be strongly influenced by the environment. To address this issue, we propose a combined strategy that includes non-invasive brain stimulation together with cognitive and behavioral interventions. [less ▲]

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