e52 Movement, postural and vestibular disorders / Annals of Physical and Rehabilitation Medicine 60S (2017) e49–e53 CO140 Head and trunk 3D orientation during heading and pointing tasks Alexandra Roren 1,∗ , Marie-Martine Lefèvre-Colau 1 , Sessi Acapo 1 , Agnès Roby-Brami 2 1 CHU Cochin, rééducation et de réadaptation de l’appareil locomoteur et des pathologies du rachis, Paris, France 2 ISIR, Paris, France ∗ Corresponding author. E-mail address: alexandra.roren@aphp.fr (A. Roren) Objective Both heading and pointing tasks may affect head and trunk since head rotation contributes to orient the gaze and trunk rotation participates to arm movement. The aim of the present study is to evaluate head and trunk 3D orientation during heading and pointing tasks. Material/Patients and methods Right arm pointing and head- ing tasks toward eight visual targets placed in a wide frontal workspace were studied in ten healthy, right handed subjects. Three-dimensional orientation of the head and trunk (flexion- extension, lateral bending and axial rotation) and upper arm were measured using an electromagnetic tracking system. Results For both heading and pointing tasks, the orientation of the head in space was closely related to the target with a coupling between rotation and contralateral bending. The trunk was sta- ble during heading but showed large leftward axial rotation during pointing as a function of target direction, coupled with right head rotation relative to the trunk. Discussion/Conclusion Our results suggest that the global rota- tions within the cervical spine compensated for trunk rotation in order to maintain an adapted orientation of the head toward the visual target. In the future, this should be taken into account for the prevention and the rehabilitation of musculoskeletal disorders. Keywords Neck; Trunk; 3D kinematics; Heading; Pointing Disclosure of interest The authors have not supplied their decla- ration of competing interest. http://dx.doi.org/10.1016/j.rehab.2017.07.197 CO141 Influence of vision conditions on postural control in right and left hemispheric lesions Serge Mesure 1,∗ , Sylvie Nadeau 2 , Noémie Duclos 2 1 Institut des Sciences du Mouvement, Réadaptation, Marseille, France 2 École de réadaptation, Université de Montréal, Centre de recherche interdisciplinaire en réadaptation (CRIR), Ville de Québec, Canada ∗ Corresponding author. E-mail address: serge.mesure@univ-amu.fr (S. Mesure) Objective Postural regulation is a prerequisite of executing func- tional activities in various environments. The integration of sensory inputs is weighted differently according to the situation and the required motor strategies. Stroke impairs postural regulation and production of motor strategies, and visual inputs might have dif- ferent influence depending on the side of the lesion. The main objective of this study was to determine whether side of hemi- spheric lesion influences the effects of visual inputs on postural regulation in the medial-lateral and anterior-posterior axes when self-imposed disturbances occur in the seated position. Material/Patients and methods We assessed 22 chronic stroke participants (12 with right and 10 with left side lesions; > 6 months) who had a single hemispheric stroke. Participants were asked to maintain their balance in a sitting position on a seesaw placed on a force platform that recorded at 40 Hz. Four conditions were tested: eyes open and closed; with alteration of the right and left visual field using goggles. The area, length and speed of the Centre of Pres- sion (COP) in the medial-lateral and anterior-posterior axes were analyzed with two-way ANOVAs to assess the effects of vision and group. Results The effects of the occlusion of visual field on postural control differed depending on the side of the lesion. In both the medial-lateral and anterior-posterior axes, the left visual field occlusion perturbed stability in the participants with the right lesion while the right visual field occlusion perturbed stability in the participants with the left lesion. In addition, the visual effect dif- fered for these two groups of patients with greater destabilization on the medial-lateral axis for those having a right side lesion. Discussion/Conclusion Our findings emphasized the dominant role of the right hemisphere on postural control under vision conditions, particularly in the medial-lateral axis where greater instability was observed in people with a right hemispheric lesion. Keywords Hemispheric; Stroke; Vision; Visual field; Posture Disclosure of interest The authors have not supplied their decla- ration of competing interest. http://dx.doi.org/10.1016/j.rehab.2017.07.198 P090 Effect of nocturnal ingestion of melatonin on the static and dynamic balance in the elderly Anis Kamoun 1 , Abdelmoneem Yahia 2,∗ , Houssem Ksentini 2 , Sameh Ghroubi 2 , Mohamed Habib Elleuch 2 1 Unité de Recherche de l’Évaluation des Pathologies de l’Appareil Locomoteur UR12ES18, Médecine Physique, Sfax, Tunisia 2 Hôpital Habib Bourguiba, Médecine Physique, Sfax, Tunisia ∗ Corresponding author. E-mail address: abdelmoneem yahia@yahoo.fr (A. Yahia) Objective Aging is characterized by a musculo-articular fragility, which could impair postural stability and consequently increases the risk of fall. Since stability decreases during aging, several stud- ies have shown that fall prevention is an effective strategy to reduce direct and indirect costs of care. The present study aimed to investi- gate the effect of nocturnal melatonin (10 mg) ingestion on postural static (with double task) and dynamic balance. Material/Patients and methods Twelve sedentary older adults voluntarily participated in this study. The experimental protocol consisted of two evaluation sessions after ingestion of 10 mg of melatonin (MEL) or Placebo (PLA), the night before the tests. For each assessment session, static stability measurements with dou- ble task (counting from 0 to add 3 each time) and dynamic (lateral, antero-posterior) on the SATEL ® force platform were performed in both conditions “open eyes” (OE) and “closed eyes” (CE). Results Age, body mass and height of the participants were 58 ± 5.74 years; 72.7 ± 4.9 kg and 1.69 ± 3.78 m, respectively. In the present study, static (bipedal with double task) and dynamic (lateral, antero-posterior) stability parameters were decreased sig- nificantly during the MEL session compared to the PLA session in the two conditions (EO, CE). For bipedal static balance, the results of this study showed a significant decrease in Long X and Long Y (29% and 30%, respectively) in the YO condition and (31%, and 33%) in the YF condition. Concerning the dynamic parameters stability in the antero-posterior axis, the results showed a decrease in the MEL session of 20% for long X and 14% for long Y in EO, and 32% for long X and 36% for long Y in the CE. For the lateral dynamic stability, the results also showed a decrease for the Long X and Long Y in the two conditions EO and CE. Discussion/Conclusion In the present study, nocturnal ingestion of MEL (10 mg) improves static and dynamic stability parameters. This improvement could be explained by the beneficial effect of MEL, since the decrease of melatonin in the elderly causes cognitive, vestibular and balance disorders. Keywords Aging; Melatonin; Postural static balance; Postural dynamic balance