Biomedical subjects

Sandhiran Patchay

Publications and source records attributed to Sandhiran Patchay.

3 recordsLinked to original sources

PubMed2003

Effect of asymmetrical limb loading on early postural adjustments associated with gait initiation in young healthy adults.

The aim of this work was to show how postural adjustments are modified in healthy subjects when gait initiation is made more difficult by an increase of the supported body weight under the starting limb. We show that the impulse due to the push of the foot against the ground is enhanced by an increase of the amplitude and duration of the initial vertical force variation. The corresponding lateral excursion of the global center of pressure (CPg) is determined mainly by this force variation, but also by lateral displacements of the centers of pressure under each foot. Rehabilitation methods of patients with gait initiation difficulties may be improved by taking into account the importance of even loading, and of the transient initial push of the starting foot.

Adaptation, Physiological↗

PubMed2003

A cross-modal interference effect in grasping objects.

The aim of the present paper was to investigate how the kinematics of a hand reaching toward a visual target would be influenced by haptic and proprioceptive input from an unseen distractor actively grasped in the other, nonreaching hand. The main results were that the amplitude of maximum grip aperture was smaller and the time to maximum grip aperture was earlier when the distractor was smaller than the target. The interference effect from the distractor was similar for both hands as they reached. Furthermore, results from a vibrating-distractor condition for passive tactile input revealed that the interference effects were evident only when the distractor was actively grasped. We suggest that neural processing of proprioceptive and tactile information relevant to distractor size produced the observed interference effects. We also emphasize the importance of active manipulation of the distractor stimulus in eliciting such interference effects.

Adult↗

PubMed2002

Early postural adjustments associated with gait initiation and age-related walking difficulties.

To better understand the functional role of early postural adjustments associated with gait initiation, we studied ground reaction forces before the first step in a group of 10 young and 18 elderly normal subjects as well as in a group of 11 patients with marche à petits pas, an age-related gait disorder in which difficulties in executing the first step are encountered. Kinematic data and ground reaction forces were recorded synchronously and processed by an ELITE motion analysis system. Start difficulties in the patients might be explained by impaired amplitudes and directions of anteroposterior forces as well as smaller values of vertical forces than in the controls walking with comparable step lengths. Indeed, the abnormalities of anteroposterior forces lead to defective propulsive forces, whereas the smaller upward reaction forces make the elevation of the starting leg more difficult. These perturbations are likely to reflect impairments of muscular synergies of the lower limbs manifested by disturbances in the agonist-antagonist coupling, and lack of coordination between both limbs.

Aged↗