Electroencephalography-based machine learning for cognitive profiling in Parkinson's disease:Preliminary results

Background Cognitive symptoms are common in patients with Parkinson's disease. Characterization of a patient's cognitive profile is an essential step toward the identification of predictors of cognitive worsening. Objective The aim of this study was to investigate the use of the combination of resting-state EEG and data-mining techniques to build characterization models. Methods Dense EEG data from 118 patients with Parkinson's disease, classified into 5 different groups according to the severity of their cognitive impairments, were considered. Spectral power analysis within 7 frequency bands was performed on the EEG signals. The obtained quantitative EEG features of 100 patients were mined using 2 machine-learning algorithms to build and train characterization models, namely, support vector machines and k-nearest neighbors models. The models were then blindly tested on data from 18 patients. Results The overall classification accuracies were 84% and 88% for the support vector machines and k-nearest algorithms, respectively. The worst classifications were observed for patients from groups with small sample sizes, corresponding to patients with the severe cognitive deficits. Whereas for the remaining groups for whom an accurate diagnosis was required to plan the future healthcare, the classification was very accurate. Conclusion These results suggest that EEG features computed from a daily clinical practice exploration modality in-that it is nonexpensive, available anywhere, and requires minimal cooperation from the patient-can be used as a screening method to identify the severity of cognitive impairment in patients with Parkinson's disease. (c) 2018 International Parkinson and Movement Disorder Society</p

Falls in ambulatory non-demented patients with Parkinson's disease

This study aimed at determining the prevalence of falling in PD patients, to assess generic and disease-specific clinical and pharmacological factors, relationship with health-related quality of life (HR-QoL) and changes in falls from OFF to ON in patients with motor fluctuations. Six-hundred and eighty-three PD patients of the COPARK survey were evaluated (11 had missing data and were excluded from the analysis). Patients with falls were identified as those with a UPDRS Item 13 ¡Ý 1 in the ON condition. All patients were assessed in a standardized manner [demographics, treatments, Unified PD Rating Scale (UPDRS), Hospital Anxiety and Depression Scale, Pittsburg questionnaire and HR-QoL scales (SF36, PDQ39)]. Falling was reported by 108/672 (16 %) PD patients during the ON state and prevalence increased according to PD severity, from 5 % in Hoehn and Yahr stage 1-60 % in stage 4. Falling was significantly related to lower HR-QoL. Falling correlated with (1) generic factors such as female gender, age at the end of academic studies and diuretics consumption, (2) motor PD-specific factors including disease severity, frozen gait, difficulties when arising from a chair, dyskinesia and higher levodopa daily equivalent dose and (3) non-motor PD-specific factors such as orthostatic hypotension and hallucinations. Falling was more frequent in OFF than in ON in 48/74 (64 %) patients with motor fluctuations and remained unchanged in 27 patients (36 %). In summary, falling affected a significant proportion of PD patients, especially in advanced stages. It was associated with a variety of generic and PD-specific factors and was related to reduced HR-QoL.Fil: Rascol, Olivier. NS-Park Network; Francia. Université Paul Sabatier; Francia. Inserm; FranciaFil: Pérez Lloret, Santiago. Université Paul Sabatier; Francia. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires". Instituto de Investigaciones Biomédicas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas; ArgentinaFil: Damier, Philippe. Hôpital Laënnec; Francia. NS-Park Network; Francia. Inserm; FranciaFil: Delval, Arnaud. Seul Centre Hospitalier Universitaire; FranciaFil: Derkinderen, Pascal. Hôpital Laënnec; FranciaFil: Destée, Alain. NS-Park Network; Francia. Inserm; Francia. Seul Centre Hospitalier Universitaire; FranciaFil: Meissner, Wassilios G.. Universite de Bordeaux; Francia. Institut des Maladies Neurodégénératives; Francia. Centre Hospitalier Universitaire de Bordeaux; FranciaFil: Tison, Francois. Universite de Bordeaux; Francia. Centre Hospitalier Universitaire de Bordeaux; Francia. Institut des Maladies Neurodégénératives; Francia. NS-Park Network; FranciaFil: Negre Pages, Laurence. Inserm; Francia. NS-Park Network; Franci

Brain metabolic abnormalities during gait with freezing in Parkinson’s disease

International audienc

Brief Communication External globus pallidus stimulation modulates brain connectivity in Huntington&apos;s disease

Positron emission tomography with O-15-labeled water was used to study at rest the neurophysiological effects of bilateral external globus pallidus (GPe) deep brain stimulation in patients with Huntington&apos;s disease (HD). Five patients were compared with a control group in the on and off states of the stimulator. External globus pallidus stimulation decreased neuronal activity and modulated cerebral connectivity within the basal ganglia-thalamocortical circuitry, the sensorimotor, and the default-mode networks. These data indicate that GPe stimulation modulates functional integration in HD patients in accordance with the basal ganglia-thalamocortical circuit model

Identification of genetic variants associated with Huntington's disease progression: a genome-wide association study

Background Huntington's disease is caused by a CAG repeat expansion in the huntingtin gene, HTT. Age at onset has been used as a quantitative phenotype in genetic analysis looking for Huntington's disease modifiers, but is hard to define and not always available. Therefore, we aimed to generate a novel measure of disease progression and to identify genetic markers associated with this progression measure. Methods We generated a progression score on the basis of principal component analysis of prospectively acquired longitudinal changes in motor, cognitive, and imaging measures in the 218 indivduals in the TRACK-HD cohort of Huntington's disease gene mutation carriers (data collected 2008–11). We generated a parallel progression score using data from 1773 previously genotyped participants from the European Huntington's Disease Network REGISTRY study of Huntington's disease mutation carriers (data collected 2003–13). We did a genome-wide association analyses in terms of progression for 216 TRACK-HD participants and 1773 REGISTRY participants, then a meta-analysis of these results was undertaken. Findings Longitudinal motor, cognitive, and imaging scores were correlated with each other in TRACK-HD participants, justifying use of a single, cross-domain measure of disease progression in both studies. The TRACK-HD and REGISTRY progression measures were correlated with each other (r=0·674), and with age at onset (TRACK-HD, r=0·315; REGISTRY, r=0·234). The meta-analysis of progression in TRACK-HD and REGISTRY gave a genome-wide significant signal (p=1·12 × 10−10) on chromosome 5 spanning three genes: MSH3, DHFR, and MTRNR2L2. The genes in this locus were associated with progression in TRACK-HD (MSH3 p=2·94 × 10−8 DHFR p=8·37 × 10−7 MTRNR2L2 p=2·15 × 10−9) and to a lesser extent in REGISTRY (MSH3 p=9·36 × 10−4 DHFR p=8·45 × 10−4 MTRNR2L2 p=1·20 × 10−3). The lead single nucleotide polymorphism (SNP) in TRACK-HD (rs557874766) was genome-wide significant in the meta-analysis (p=1·58 × 10−8), and encodes an aminoacid change (Pro67Ala) in MSH3. In TRACK-HD, each copy of the minor allele at this SNP was associated with a 0·4 units per year (95% CI 0·16–0·66) reduction in the rate of change of the Unified Huntington's Disease Rating Scale (UHDRS) Total Motor Score, and a reduction of 0·12 units per year (95% CI 0·06–0·18) in the rate of change of UHDRS Total Functional Capacity score. These associations remained significant after adjusting for age of onset. Interpretation The multidomain progression measure in TRACK-HD was associated with a functional variant that was genome-wide significant in our meta-analysis. The association in only 216 participants implies that the progression measure is a sensitive reflection of disease burden, that the effect size at this locus is large, or both. Knockout of Msh3 reduces somatic expansion in Huntington's disease mouse models, suggesting this mechanism as an area for future therapeutic investigation

Potentiels évoqués nociceptifs par stimulation laser CO2 (valeurs normatives aux membres supérieurs et inférieurs)

Contexte : L étude des neuropathies sensitives à petites fibres sollicite des techniques spécifiques. Les potentiels évoqués nociceptifs par stimulation laser (PEL) constituent un examen de choix dans l analyse de la voie thermoalgique en activant sélectivement les fibres A et C. L objectif de cette étude a été d établir des valeurs normatives des potentiels évoqués tardifs et ultra-tardifs aux membres supérieurs et inférieurs. Méthode : A l aide d un laser CO2, nous avons enregistré les potentiels évoqués nociceptifs de 30 sujets témoins par stimulation de la face dorsale des mains et des pieds. Nous avons mesuré les seuils de stimulation des fibres A et C, les latences des composantes N2 et P2 au niveau cortical et les amplitudes des PEL. Nous avons également étudié l influence de l âge, du sexe, de la taille et du site stimulé sur les valeurs des différentes composantes. Résultats : Les seuils douloureux (médiane (quartiles 1-3)) étaient pour les PEL tardifs (fibres A ) de 46C (48-50) aux membres supérieurs et de 49C (47-52) aux membres inférieurs. Les latences des composantes N2 et P2 étaient de 255 ms (230-279) et 388 ms (298-415) aux membres supérieurs, et l amplitude de 22,7 V (18,9-31,3). Aux membres inférieurs, les latences étaient de 293 ms (265-320) et 452 ms (414-489), et l amplitude de 25,2 V (20,9-35,9). Les seuils étaient plus bas chez les femmes. Les latences étaient plus courtes aux membres supérieurs. L amplitude de P2 augmentait avec la taille. L amplitude des complexes N2P2 diminuait avec l âge. Les seuils douloureux pour les PEL ultra tardifs (fibres C) étaient de 40,5C (40-41) aux membres supérieurs et 41C (40-42) aux membres inférieurs. Les PEL ultra tardifs étaient plus difficiles à obtenir, et ont été enregistré chez 20 sujets. Les latences des composantes N2 et P2 étaient de 813 ms (754-877) et 979 ms (919-1061) aux membres supérieurs, et l amplitude de 14,1 V (11,2-19). Aux membres inférieurs, les latences étaient de 1302 ms (1247-1374) et 1518 ms (1432-1598), et l amplitude de 14,9 V (12,5-17,9). Les latences étaient plus courtes aux membres supérieurs. Il n y avait pas de variation de seuil ou d amplitude selon le sexe ou l âge. Conclusion : Cette étude a pu établir les valeurs normatives des seuils douloureux et PEL tardifs et ultra-tardifs par stimulation au laser CO2 des fibres A et C aux membres supérieurs et inférieurs, en soulignant les différences physiologiques liées au sexe, à l âge, à la taille et au site de stimulation. Les résultats concernant les fibres A étaient similaires à ceux des études précédentes. Peu de données de littérature concernent les fibres C ; la technique que nous avons utilisée a permis une stimulation spécifique de ces fibres chez 20 sujets sur 30.LILLE2-BU Santé-Recherche (593502101) / SudocSudocFranceF

Activation corticale liée au mouvement dans les formes familiales de maladie de Parkinson par analyse des désynchronisations et synchronisations des rythmes EEG

LILLE2-BU Santé-Recherche (593502101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Contribution of transcranial magnetic stimulation in assessing parietofrontal connectivity during gesture production in healthy individuals and brain-injured patients

International audienceParietofrontal (PF) networks link the posterior parietal cortex to premotor and prefrontal areas, and are involved in the control of many motor and cognitive behaviors in healthy humans. In recent years, electrophysiological experiments have provided a better understanding of the functional specificity and temporal involvement of the PF networks’ different components during the planning of visually guided upper limb movements. In particular, transcranial magnetic stimulation has been used to temporarily inactivate a cortical area (virtual lesions) or to assess connectivity using paired-pulse protocols)). This approach has shed new light on the neural mechanisms that underlie the planning stages of the reaching and grasping phases of transitive movements. Reaching and grasping were often presented as two distinct processes; in fact, the respective involvement of dorsolateral and dorsomedial networks may depend on the movement's complexity and the need for precise coordination between the two phases. The dorsolateral parietofrontal network (linking the anterior part of the intraparietal sulcus to the ventral premotor cortex) is involved in the grasping phase (i.e. hand shape and grip force scaling), whereas the dorsomedial part (from the posterior part of the intraparietal sulcus and the superior parieto-occipital cortex to the dorsal premotor cortex) appears to be involved not only in the reaching phase but also in more complex visually guided grasping movements. Changes in parietofrontal connectivity following brain injury might explain the impairments in visually guided upper limb movements observed in patients (such as optic ataxia and the motor component of spatial neglect). Lastly, parietofrontal changes may reflect neuronal plasticity in motor function recovery

Parkinson's Disease-Related Impairments in Body Movement, Coordination and Postural Control Mechanisms When Performing 80° Lateral Gaze Shifts.

We investigated early signs of Parkinson's disease-related impairment in mediolateral postural control. Thirty-six participants (18 Hoehn & Yahr stage 2 patients in the off-drug condition and 18 healthy controls) were studied in a stationary gaze condition and when performing 80° lateral gaze shifts at 0.125 and 0.25 Hz. Body sway, coordination and postural control mechanisms were analyzed. All participants performed the visual tasks adequately. The patients were not unstable in the stationary gaze condition. In both groups, mediolateral ankle- and hip-based postural control mechanisms were significantly more active under gaze shift conditions than under the stationary gaze condition. As expected, the patients exhibited significantly greater angular movements of the lower back and significantly lower angular movements of the head (relative to controls) when performing gaze shifts. When considering linear displacements (rather than angular movements), the patients exhibited significantly greater displacements of the lower back and lower, slower displacements of the head than controls under gaze shift conditions. Relative to controls, the patients performed "en block" body movements. Overall, our results show that the patients' ankle- and hip-based mediolateral postural control mechanisms did not adapt to the difficulty of the visual task being performed