Delayed postural control during self-generated perturbations in the frail older adults

International audiencePurpose: The aim of this study was to investigate the coordination between posture and movement in pathological aging (frailty) in comparison with normal aging, with the hypothesis that in pathological aging, postural control evolves towards a more reactive mode for which the perturbation induced by the movement is not anticipated and leads to delayed and late postural adjustments. Methods: Elderly subjects performed rapid focal arm-raising movements towards a target, from an upright standing position in two stimuli conditions: simple reaction time and choice reaction time (CRT). Hand and center of pressure (CoP) kinematics were compared between a control group and a frail group of the same age. Results: In frail individuals, the entire movement was impaired and slowed down. In addition, postural adjustments that classically precede and accompany the focal arm movement were delayed and reduced, especially in the CRT condition in which the motor prediction is more limited. Finally, a correlation between the time to CoP maximal velocity and the timed up-and-go score was observed. Conclusion: In these patients, it was concluded that the control of the CoP displacement evolved from a proactive mode in which the perturbation associated with the arm movement is anticipated toward a more reactive mode in which the perturbation is compensated by late and delayed adjustments

Low-cost motion analysis device: Accuracy of velocity measurements during arm movements in comparison with laboratory system - A pilot study

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Practice-Related Improvements in Postural Control During Rapid Arm Movement in Older Adults: A Preliminary Study

International audienceBackground. Postural control associated with self-paced movement is critical for balance in older adults. The present study aimed to investigate the effects of a virtual reality based program on the postural control associated with rapid arm movement in this population. Methods. From an upright standing position, participants performed rapid arm raising movements toward a target. Practice-related changes were assessed by pre- and posttest comparisons of hand kinematics and center of pressure displacement parameters measured in a training group (mean age: 71.50 +/- 2.67 years, n = 8) and a control group (mean age: 72.87 +/- 3.09 years, n = 8). Training group participants took part in six sessions (35-40 minutes per session, three sessions per week). During the two test sessions, arm raising was analyzed under two conditions of stimuli: choice reaction time and simple reaction time. Results. We observed improvements in the arm movement after training under both conditions of stimuli. The initial phase of the center of pressure displacement, especially the anticipatory postural adjustments, was improved in the choice reaction time condition. Conclusions. Our short training program resulted in motor optimization of the postural control associated with rapid arm movements, and this implies central changes in motor programming