Maladaptive One-Leg Balance Control in Parkinson’s Disease

Balance disorders are very frequent in Parkinson’s disease (PD). One-leg stance performance is a predictor of fall risk. We investigated one-leg stance strategies in people with PD. We hypothesized that patients would choose, and better perform on, the leg on the least affected body side. Fifty participants with 2 to 19 years of PD duration stood on one leg while ON medication. The leg spontaneously chosen was recorded. Performance was compared between the spontaneously chosen vs. contralateral, and most vs. least stable legs. Influence of disease duration, severity, age, cognition, and motor fluctuations was analyzed. Twenty-eight patients spontaneously stood on the leg of the least affected body side, which was not always the most stable one. The chosen standing leg was influenced by disease duration with a switch between the least vs. most affected body side after seven years of disease duration. Fourteen patients (28%) spontaneously stood on their least stable leg. Thus, some patients with PD choose the least stable leg when asked to perform one-leg stance. It is important to identify these patients since they may be at greater risk of falls and/or gait difficulties. Specific rehabilitation may help prevent such maladaptive strategy

Pedunculopontine nucleus area oscillations during stance, stepping and freezing in Parkinson's disease.

International audienceThe pedunculopontine area (PPNa) including the pedunculopontine and cuneiform nuclei, belongs to the mesencephalic locomotor region. Little is known about the oscillatory mechanisms underlying the function of this region in postural and gait control. We examined the modulations of the oscillatory activity of the PPNa and cortex during stepping, a surrogate of gait, and stance in seven Parkinson's disease patients who received bilateral PPNa implantation for disabling freezing of gait (FOG). In the days following the surgery, we recorded behavioural data together with the local field potentials of the PPNa during sitting, standing and stepping-in-place, under two dopaminergic medication conditions (OFF and ON levodopa). Our results showed that OFF levodopa, all subjects had FOG during step-in-place trials, while ON levodopa, stepping was effective (mean duration of FOG decreasing from 61.7±36.1% to 7.3±10.1% of trial duration). ON levodopa, there was an increase in PPNa alpha (5-12 Hz) oscillatory activity and a decrease in beta (13-35 Hz) and gamma (65-90 Hz) bands activity. PPNa activity was not modulated during quiet standing and sitting. Our results confirm the role of the PPNa in the regulation of gait and suggest that, in Parkinson disease, gait difficulties could be related to an imbalance between low and higher frequencies

Efficacité de la démonstration explicitée ou silencieuse pour l'apprentissage de la course de haies chez l'enfant de 7 à 10 ans

Efficacité des procédures d'apprentissage par observation (modélisation) pour l'acquisition et la rétention d'une habileté sportive, ici un éducatif de course de haies, chez l'enfant débutant dans l'activité

Mémoire de travail et mémoire implicite : influence de l'expertise en situation de prise de décision en football

Debû Bettina, Zoudji Bachir, Thon Bernard. Mémoire de travail et mémoire implicite : influence de l'expertise en situation de prise de décision en football. In: Les Cahiers de l'INSEP, n°34, 2003. Expertise et sport de haut niveau. pp. 229-233

Developmental changes in unimanual and bimanual aiming movements.

International audienceThe aim of this study was twofold: (a) analyze the development of reaction time (RT) and movement time (MT) for bimanual and unimanual movements and (b) investigate the interaction of age and sex on the changes in RT and MT. Participants (5-, 8-, and 11-year-olds) were asked to aim at target buttons under three conditions of movement: unimanual, bimanual symmetrical, and bimanual nonsymmetrical. As expected, RTs for bimanual symmetrical movements were shorter than RTs for unimanual and bimanual nonsymmetrical movements in the 5-year-olds. By the age of 8, bimanual nonsymmetrical movements still yielded longer RTs than unimanual and bimanual symmetrical movements, which no longer differed from each other. Regarding MT, in the 2 younger groups there was an advantage of unimanual over bimanual symmetrical movements. The latter were executed faster than nonsymmetrical movements at all ages. These results suggest that the evolution of RT and MT with age reflects development of interhemispheric transfer of information. It appears that the functional improvement of such transfer, which depends on the corpus callosum, progressively enables contralateral motor inhibition and the coordination of complex bilateral movements. The exchange of movement feedback information could mature more slowly than that of feed-forward information, explaining the extended time course of MT evolution

Assessment of Static Postural Control in Teenagers with Down Syndrome

International audienceThis study evaluated stance control in 24 teenagers with and without Down syndrome (DS) by (a) assessing center of foot pressure variables under different conditions of availability of visual and somatosensory inputs and (b) analyzing postural perturbation and adaptation following abrupt changes in visual information. Results showed no gender-related differences in either group. Group comparison revealed similar strategies in adolescents with and without DS, although quantitative differences may exist in the ability to integrate sensory inputs to control stance. Adaptation to changing environmental conditions varied greatly from one individual to another in the two groups. Finally, comparison of the two experiments suggests that the increased postural oscillations reported for the sample with DS on long lasting recordings could be related to insufficient allocation of cognitive resources in stable environments

Se décider bien... et vite !

Tous les sportifs experts ont engrangé de nombreuses situations de jeu de façon automatique et non consciente dans leur mémoire implicite. Il sont ainsi capables de réagir correctement face à un adversaire. Etude du phénomène

Imaging gait disorders in parkinsonism: a review

Gait difficulties--including freezing of gait--are frequent and disabling symptoms of advanced Parkinson's disease and other parkinsonian syndromes. They respond poorly to current medical and surgical treatments, making patient management very difficult. The underlying pathophysiology remains largely unknown. The late onset of levodopa resistance of Parkinson's disease gait abnormalities has been suggested to result from the progressive extension of the degenerative process to non-dopaminergic structures involved in locomotion, such as cortico-frontal and brainstem networks. Deficiencies in other neurotransmission systems, involving acetylcholine, serotonin or norepinephrine, have also been evoked. Neuroimaging tools appear well suited to decipher the cerebral substrates of parkinsonian gait disorders and their modulation by dopaminergic medication or deep brain stimulation. Here the main functional and metabolic neuroimaging studies aimed at identifying these cerebral networks are reviewed, in both healthy subjects and parkinsonian patients. After a brief overview of the physiology and pathophysiology of gait control, the methodology, main results and limits of the studies published to date are examined. The most promising methods to examine gait difficulties and their response to currently available treatments are then discussed

Influence du type d'action et de latéralisation sur la prise de décision chez les experts et novices en situation de jeu de football simulée

Zoudji Bachir, Debû Bettina, Thon Bernard. Influence du type d'action et de latéralisation sur la prise de décision chez les experts et novices en situation de jeu de football simulée. In: Les Cahiers de l'INSEP, n°34, 2003. Expertise et sport de haut niveau. pp. 353-357