Effect of age on anticipatory postural adjustments in unilateral arm movement.

Aging is frequently accompanied by a deterioration in postural control. Accordingly, the elderly adopt postural strategies in order to maintain balance. The purpose of this study was to compare anticipatory postural adjustments in (healthy) 10 young and 10 elderly subjects using electromyography (EMG) and biomechanical parameters.

Vertical torque allows recording of anticipatory postural adjustments associated with slow, arm-raising movements.

Background: When performed in the upright position, voluntary arm-raising movements perturb balance. The maintenance of equilibrium requires postural adjustments, some of which can be anticipatory. It is usually suggested that the role of anticipatory postural adjustments is to stabilise the whole body centre of mass.

[Anticipatory postural adjustments associated with arm flexion: interest of vertical torque].

Objective: To find a biomechanical parameter able to characterize postural adjustments in different movement conditions.

Methods: The arm-raising movement performed during the upright human position imposes a vertical torque (Tz) that can be measured by a force plate-form. This torque was studied in ten healthy young subjects with opto electronic system Vicon 370.

Effects of subthalamic nucleus stimulation and levodopa treatment on gait abnormalities in Parkinson disease.

Background: Stimulation of the subthalamic nucleus is proposed for the treatment of patients presenting with severe Parkinson disease. The effect on gait is not clearly established.

Objectives: To evaluate objectively the influence of bilateral subthalamic nucleus stimulation on gait in Parkinson disease and to compare it with the effects of levodopa treatment.

Basic mechanisms of central rhythms reactivity to preparation and execution of a voluntary movement: a stereoelectroencephalographic study.

Objective: To localize the sources of mu, beta and gamma rhythms and to explore the functional significance of their reactivity.

Methods: We used the method of quantification of event-related desynchronization (ERD) and synchronization (ERS) to analyze the reactivity of intracerebral rhythms recorded in stereoelectroencephalography within the sensorimotor areas during the preparation and the execution of a simple self-paced hand movement. We recorded 3 epileptic subjects who were explored before a surgical treatment.

Ankle dorsiflexion delay can predict falls in the elderly.

The aim of this study was to investigate the kinematic and kinetic characteristics of walking in healthy non-faller elderly in order to develop predictive parameters for falls. A 1-year prospective trial was completed on a walking circuit with two integrated force platforms and an optoelectronic system for three-dimensional movement analysis. Gait was investigated in 54 volunteers who were healthy people over 60 who had not fallen in the previous year.

Influence of pallidal stimulation and levodopa on gait and preparatory postural adjustments in Parkinson's disease.

In order to assess the influence of the bilateral internal globus pallidus (GPi) stimulation on gait and postural instability in Parkinson's disease (PD), we compared gait kinematic parameters and preparatory postural adjustments before and 3 months after stimulation in off- and on-drug conditions for seven patients. Gait kinematic parameters and displacements of centre of pressure (CP) and shoulder computed before a lateral raising task of the leg, were recorded using optoelectric Vicon system. Levodopa (L-dopa) induced a clear benefit for gait velocity (related to an increase of stride length) and also an increase of swing phase duration.