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International audience; Hypermobile Ehlers–Danlos syndrome (hEDS) is a connective tissue disorder characterized by proprioceptive impairments. Previously, it has been shown that hEDS patients have altered gait patterns; however,no study has investigated how hEDS patients spontaneously allocate attention during dual-task walking under varying cognitive demand. A low cognitive demand would allow patients to allocate sufficient attention to both tasks; conversely, a high cognitive demand would require them to prioritize gait control over the cognitive task performance.12 hEDS patients and 12 controls walked on a self-paced treadmill for 2 minutes during single-task and dual-task (while performing an auditory 0-back or 2-back task) in a virtual environment. Separates ANOVAs were conducted for cognitive (d-prime, reaction time) and gait (mean and standard deviation of spatio-temporal parameters, statistical persistence/anti-persistence in step speed time series) dependent variables.Patients showed lower cognitive and gait performance compared to controls. Cognitive performance further declined with a concurrent walking task in patients only. However, dual-task-related changes in gait were similar in both groups, revealing beneficial and detrimental effects under low and high cognitive demand, respectively.Gait relies more on cognitive control mechanisms in patients so that, as the demand increases, hEDS patients are more likely to prioritize gait control at the expense of cognitive performance.

International audience; BackgroundWhile most fractures are caused by falls, not all falls result in fractures. Risk factors for falls are well established, but only weak associations have been demonstrated for risk factors for fractures. Conflicting results on the implication of bone mineral density (BMD) suggest that other risk factors should be studied, such as gait and balance disorders.AimsGait and postural stability in challenging conditions were, therefore, compared between fallers with and without fracture.MethodsWe enrolled 80 adults aged 55 and older who fell in the previous year. We compared gait and posture after obstacle crossing between fallers with an upper-limb fracture (n = 38), and fallers without fracture (n = 42). Data on BMD, body mass index, handgrip strength, fear of falling, number of comorbidities, number of falls, global cognition, executive functioning and education level were collected.ResultsCompared to fallers without fracture, fallers with fracture had significant lower gait velocity (Likelihood-Ratio = 4.93; P = 0.03) and lower postural stability during stabilization after obstacle crossing (Likelihood-Ratio = 10.99; P

International audience; Gait control is a complex movement, relying on spinal, subcortical, and cortical structures. The presence of deficits in one or more of these structures will result in changes in gait automaticity and control, as is the case in several neurodegenerative diseases, such as Alzheimer’s disease (AD) and Parkinson’s disease (PD). By reviewing recent findings in this field of research, current studies have shown that gait performance assessment under dual-task conditions could contribute to predict both of these diseases. Such suggestions are relevant mainly for people at putatively high risk of developing AD (i.e., older adults with mild cognitive impairment subtypes) or PD (i.e., older adults with either Mild Parkinsonian signs or LRRK2 G2019S mutation). Despite the major importance of these results, the type of cognitive task that should be used as a concurrent secondary task has to be selected among the plurality of tasks proposed in the literature. Furthermore, the key aspects of gait control that represent sensitive and specific “gait signatures” for prodromal AD or PD need to be determined. In the present perspective article, we suggest the use of a Stroop interference task requiring inhibitory attentional control and a set-shifting task requiring reactive flexibility as being particularly relevant secondary tasks for challenging gait in prodromal AD and PD, respectively. Investigating how inhibition and cognitive flexibility interfere with gait control is a promising avenue for future research aimed at enhancing early detection of AD and PD, respectively.

The aim of the present study was to assess the consequences of a simplification of the electrophysiological procedure on the post-operative clinical outcome after subthalamic nucleus implantation in Parkinson disease.Microelectrode recordings were performed on 5 parallel trajectories in group 1 and less than 5 trajectories in group 2. Clinical evaluations were performed 1 month before and 6 months after surgery.After surgery, the UPDRS III score in the off-drug/on-stimulation and on-drug/on-stimulation conditions significantly improved by 66,9% and 82%, respectively in group 1, and by 65.8% and 82.3% in group 2 (P0.05). Meanwhile, the total number of words (P0.05) significantly decreased for fluency tasks in both groups. Motor disability improvement and medication reduction were similar in both groups.Our results suggest that the electrophysiological procedure should be simplified as the team's experience increases.

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International audience; BACKGROUND: In our stereotactic procedure, intraoperative radiological documentation of electrode localization is performed using the Stereoplan. The aim of the study was to evaluate its accuracy. PATIENTS AND METHODS: Data of 20 consecutive patients, treated for Parkinson's disease by implantation of deep brain stimulators into the subthalamic nucleus, were collected prospectively. During surgery, Stereoplan coordinates of the tip of the central macroelectrodes were compared with intended coordinates along the central trajectory at 4 levels: (1) 10 mm above the anatomical target, (2) in the target, (3) in the substantia nigra pars reticulata, and (4) at the depth of contact 1. Before the frame's removal, Stereoplan coordinates of the contacts of the definitive electrode were compared with postoperative MRI coordinates. The mean of the differences was calculated in the x-, y-, and z-axis. Clinical results at 6 months were recorded. RESULTS: The mean of the differences between Stereoplan coordinates and intended coordinates for the macroelectrodes was lower than 1 mm. A submillimeter difference was also found for the definitive contacts. At 6 months, the Unified Parkinson's Disease Rating Scale III score improved by 70.6% compared with the baseline score. Dyskinesia and motor fluctuations decreased by 85.7 and 87%, respectively (p < 0.0001). CONCLUSION: Stereoplan could be considered an accurate intraoperative radiological system which assures the correct position of the electrode in the anatomical target.