Age-related differences in postural reaction time and coordination during voluntary sway movements

Comparação da oscilação postural estática na posição sentada entre jovens e idosos saudáveis

“…Combined with the inability to select the relevant sensory information, the reduction in the efficiency of the sensory systems could be responsible for an increase in body sway in the standing posture and for the postural unbalance in older adults 23,27 . Recently, Tucker et al 20 compared the reaction times and the pattern of temporal coordination of the CP of young and older adults and found a more rigid pattern associated with advanced age during the maintenance of postural control in the standing position. According to the authors, older subjects adopt more rigid movements to maintain body stability in challenging conditions, which may be related to the joints' musculoskeletal and ligament changes or to a strategy of active postural response 20 .…”

“…These studies indicated that older adults do not reduce body sway effectively during the stair-to-floor transition and that they are more careful when submitted to a faster gait due to the fear of losing their balance. Other studies have investigated reaction and recovery times after an external disturbance 20 and static balance in the standing position 21 using the force platform to compare the postural sway of young and older adults. It has been already demonstrated that older adults have slower reaction times for both static and dynamic reactions.…”

Visual field dependence is associated with reduced postural sway, dizziness and falls in older people attending a falls clinic

“…walking and stair climbing) [18] and under different experimental conditions in response to a postural threat, including platform movements [19,20], reaching or bending forward [21,22], voluntary rotations in the lateral or yaw plane [22,23] and during gait [24]. Increased muscle co-activation in older adults has often been described as a compensatory mechanism to increase joint stiffness to enhance 10 joint and postural stability [25,26,27]. This response has been associated with physiological arousal [16] and fear of falling [28,29,30] with the rationale that people who are afraid to fall co-contract in anticipation of postural perturbations [31,29].…”

“…It has been shown that excessive muscle co-activation increases postural rigidity and reduces the degrees of freedom in the postural control system [27,34]. This may compromise the ability to perform voluntary responses or adjust to unexpected perturbations [35,36] and hence increase the risk of falling [18].…”

Le coût attentionnel associé aux fonctions exécutives impliquées dans le contrôle postural

“…En effet de nombreusesétudes ont montré, dans des conditions de double tâche, une dégradation de la performance dans la tâche secondaire chez des personnesâgées non observée chez de jeunes adultes (Brown, Sleik, & Winder, 2002 ;Mahboobina, Loughlin, & Redfern, 2007 ;Maylor & Wing, 1996 ;Tucker, Kavanagh, Barrett, & Morrison, 2008 ;Gage, Sleik, Polych, McKenzie, & Brown, 2003 ;Teasdale & Simoneau, 2001 ;Marsh & Geel, 2000). Une dégradation aégalementété mesurée pour une population de personnesâgées entre une posture simple (par exemple assise) et une posture plus complexe (Teasdale & Simoneau, 2001 ;Lajoie & Gallagher, 2004 ;Lajoie et al, 1996), ou encore entre la phase de simple et de double appui au cours de la marche (Lajoie, Teasdale, Bard, & Fleury, 1993).…”