Peer reviewed article authored by (Kubicki A, Bonnetblanc F, Petrement G, Ballay Y, Mourey F). Read article or submit your manuscript for publishing.

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. 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. 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. 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.

OBJECTIVES: Motor deficiency is associated with cognitive frailty in patients with Mild Cognitive Impairments (MCI). In this study we aimed to test the integrity of the muscle synergy involved in an arm-pointing movement in MCI patients, non-impaired functionally. Thus, we were able to test the hypothesis that early motor indicators exist in this population at a preclinical level. METHODS: The electromyographic signals were collected for 11 muscles in 3 groups: Young Adults (YA), Aged Adults (AA), and MCI patients. The AA and MCI groups presented the same functional status. Each subject performed twenty arm-pointing movements from a standing position. RESULTS: The main differences were (1) delayed activation of the right Biceps Femoris and the right Erector Spinae at L3 in MCI patients and AA compared with YA groups ; (2) earlier activation of the left Obliquus internus in MCI compared with AA group and (3) concerning the left Erector spinae at L3, a delay for the AA compared with YA but an earlier activation for the MCI compared with both AA and YA. These temporal differences in muscle synergies were linked with executive functions of MCI patients. INTERPRETATION: The motor program changes highlighted in our patient (MCI) group suggest that discrete modifications of the motor command seem to exist even in the absence of functional impairment. Instead of showing an indication of delayed muscle activation in the MCI patients, our results highlight some early activation of several trunk muscles, probably used in a more cautious motor behavior.

Kinematic analysis of motor strategies in frail aged adults during the Timed Up and Go: how to spot the motor frailty? Asma Hassani,1 Alexandre Kubicki,2,3 Vincent Brost,1 France Mourey,2,4 Fan Yang1 1Laboratoire LE2I CNRS 6306, Université de Bourgogne, Dijon, France; 2Institut National de la Santé et de la Recherche Médicale (INSERM), Cognition Action et Plasticité Sensori-Motrice, Campus Universitaire, Université de Bourgogne, Dijon, France; 3Centre Hospitalier Universitaire de Dijon, Hôpital de Champmaillot, Dijon, France; 4Faculté de Médecine, Université de Bourgogne, Dijon, France Objective: The purpose of this work was to analyze and compare the movement kinematics of sit-to-stand (STS) and back-to-sit (BTS) transfers between frail aged adults and young subjects, as well as to determine the relationship between kinematic changes and functional capacities. Methods: We analyzed the Timed Up and Go (TUG) movements by using a 3D movement analysis system for real-time balance assessment in frail elderly. Ten frail aged adults (frail group [FG]) and ten young subjects (young group [YG]) performed the TUG. Seven spatiotemporal parameters were extracted and compared between the two groups. Moreover, these parameters were plotted with TUG test duration. Results: The experiments revealed that there were significant differences between FG and YG in trunk angle during both STS and BTS, and in TUG duration. The trunk angle of the young subjects was more than two times higher than that of the FG. As expected, the TUG duration was higher in the FG than in YG. Trunk angles during both transfers were the most different parameters between the groups. However, the BTS trunk angle and STS ratio were more linked to functional capacities. Conclusion: There was a relationship between kinematic changes, representing the motor planning strategies, and physical frailty in these aged adults. These changes should be taken into account in clinical practice. Keywords: aging, Timed Up and Go test, kinematics, frailty effects