Improving Dual-Task Walking Paradigms to Detect Prodromal Parkinson’s and Alzheimer’s Diseases

International audienceGait 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

Comparaison de l'évaluation qualitative et quantitative de la motricité en période on et off dans la maladie de Parkinson idiopathique

ROUEN-BU Médecine-Pharmacie (765402102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Etude des mécanismes du contrôle de l équilibre au cours de l initiation de la marche chez l homme

Nous proposons un nouveau paramètre biomécanique issu de la vitesse verticale du centre de gravité (CG). Au cours de la phase pendulaire, il existe une chute du CG suivie d un freinage de la chute du CG. La chute du CG peut être stoppée par le pied pendulaire qui vient heurter le sol (mode passif) ou par activation des muscles fléchisseurs de la cheville avant le poser du pied (mode actif). Lors de l initiation de la marche, la chute du CG était freinée avant le poser du pied chez tous les sujets témoins (n=34), grâce à une contraction simultanée du muscle soléaire du pied d appui suggérant qu il s agit d un mécanisme physiologique actif. Le freinage n était pas altéré avec l âge. Le freinage était très altéré chez les patients atteints de paralysie supranucléaire progressive (PSP, n=10) caractérisée par une instabilité posturale majeure. Un tiers des patients parkinsoniens (n=32) sans lévodopa présentaient un freinage anticipé contre la moitié des patients avec la lévodopa, suggérant des lésions non dopaminergiques surajoutées. Les parkinsoniens sans freinage anticipé avaient une surface mésencéphalique plus petite associée à un score clinique de marche et d équilibre plus altéré, par rapport aux parkinsoniens qui freinaient. La stimulation bilatérale de la substantia nigra pars reticulata (SNr) chez les patients parkinsoniens (n=7) améliorait le freinage. Le freinage semble être un paramètre simple d évaluation du contrôle postural au cours de la marche. La SNr pourrait être impliquée dans le mécanisme de freinage probablement par ses projections vers le noyau pédonculopontin qui subit une perte neuronale massive chez les PSP et partielle chez les parkinsoniens.We propose a novel biomechanical parameter derived from vertical velocity of the centre of gravity (CG). During the single support phase, there is a CG fall due to the force of gravity, followed by a braking of the CG fall. The CG fall can be arrested by the swing limb hitting the ground ( passive mode) or by activation of the ankle plantar flexors prior to foot-contact ( active mode). During gait initiation, the CG fall was reversed before foot-contact in all healthy subjects (n=34), related to the stance-leg simultaneous soleus contraction, suggesting that the braking before foot-contact is an active physiological mechanism. Age did not influence the braking. Braking was dramatically decreased in patients with progressive supranuclear palsy (PSP, n=10) characterized by a major postural instability. One third of the patients with Parkinson s disease (PD, n=32) without levodopa, showed a braking before foot-contact versus only a half with levodopa, perhaps as a result of non-dopaminergic lesions. PD patients with normal braking had significantly better gait and balance scores and higher mesencephalic surface areas compared to patients with impaired braking. High frequency substantia nigra pars reticulata (SNr) stimulation in 7 PD patients improved axial, but not distal parkinsonian motor symptoms, with an increase in the braking capacity. The braking of the CG fall is a simple assessment parameter of postural control during gait. Our results imply that the SNr output is involved in the braking mechanism probably as a result of its projection to the pedonculopontine nucleus, which show a massive neuronal loss in PSP patients and a partial loss in PD patients.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Does neuromuscular electrical stimulation training of the lower limb have functional effects on the elderly?: A systematic review

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Loss of gait control assessed by cognitive-motor dual-tasks: pros and cons in detecting people at risk of developing Alzheimer’s and Parkinson’s diseases

International audienceAlzheimer’s and Parkinson’s diseases are age-related progressive neurodegenerative diseases of increasing prevalence worldwide. In the absence of curative therapy, current research is interested in prevention, by identifying subtle signs of early-stage neurodegeneration. Today, the field of behavioral neuroscience has emerged as one of the most promising areas of research on this topic. Recently, it has been shown that the exacerbation of gait disorders under dual-task conditions (i.e., simultaneous performance of cognitive and motor tasks) could be a characteristic feature of Alzheimer’s and Parkinson’s diseases. The cognitive-motor dual-task paradigm during walking allows to assess whether (i) executive attention is abnormally impaired in prodromal Alzheimer’s disease or (ii) compensation strategies are used in order to preserve gait function when the basal ganglia system is altered in prodromal Parkinson’s disease. This review aims at (i) identifying patterns of dual-task-related gait changes that are specific to Alzheimer’s and Parkinson’s diseases, respectively, (ii) demonstrating that these changes could potentially be used as prediagnostic markers for disease onset, (iii) reviewing pros and cons of existing dual-task studies, and (iv) proposing future directions for clinical research

Clinical and electroencephalographic abnormalities during the full duration of a sporadic hemiplegic migraine attack

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Ankle dorsiflexors and plantarflexors neuromuscular electrical stimulation training impacts gait kinematics in older adults: A pilot study

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Plantar Flexor Strength Training With Home-Based Neuromuscular Electrical Stimulation Improves Limits of Postural Stability in Older Adults

International audienceBackground : The study aimed to determine whether improved muscle strength after 12 weeks of neuromuscular electrical stimulation (NMES) of plantar and dorsiflexors could result in better limits of stability in older adults. Methods : Twenty-seven participants were divided into a control group and a neuromuscular home-based training group. The training group performed a 3-month long NMES training of both plantar and dorsiflexors. Ankle flexor strength and limits of stability were measured. A mediation analysis was conducted to determine whether the NMES effect on the limits of stability was mediated by increased strength. Results : The NMES training increased plantar flexor strength (+47%; β = 0.217, P = .02), and this increase predicted the anterior limits of stability improvement (+27%; β = 0.527, P = .02). The effect of the NMES on the limits of stability was fully mediated by the plantar flexor strength increase (indirect effect: β = 0.1146; 95% confidence interval, 0.020–0.240). Conclusion : It seems that NMES improves the limits of stability through its positive effect on muscle strength. NMES may be utilized in fall-prevention programs

Age-related changes in the center of mass velocity control during walking.

International audienceDuring walking, the body center of mass oscillates along the vertical plane. Its displacement is highest at mid-swing and lowest at terminal swing during the transition to double support. Its vertical velocity (CoMv) has been observed to increase as the center of mass falls between mid- and late swing but is reduced just before double support. This suggests that braking of the center of mass is achieved with active neural control. We tested whether this active control deteriorates with aging (Experiment 1) and during a concurrent cognitive task (Experiment 2). At short steps of 0.4m but older subjects did so to a lesser extent. During the cognitive task, young subjects increased CoMv control (i.e. increase in CoMv braking) while maintaining step length and walking speed. Older subjects on the other hand, did not increase CoMv control but rather maintain it by reducing both step length and walking speed. These results suggest that active braking of the CoM during the transition to double support predominates in steps >0.4m. It could be a manifestation of the balance control system, since the braking occurs at late stance where body weight is being shifted to the contralateral side. The active braking mechanism also appears to require some attentional resource. In aging, reducing step length and speed are strategic to maintaining effective center of mass control during the transition to double support. However, the lesser degree of control in older adults indicates a true age-related deficit

Prediagnostic markers of idiopathic Parkinson’s disease: Gait, visuospatial ability and executive function

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