Age Related Decline in Postural Control Mechanisms

Abstract

In order to study voluntary and reflexive mechanisms of postural control, young and elderly persons were given large-fast and small-slow ankle-rotation postural disturbances while standing on a movable platform capable of measuring ground reaction forces. Large-fast rotations were employed to activate long-loop reflexes, and small-slow rotations were employed to tap the higher level sensory integration aspects of postural control. Overall, the elderly persons exhibited more perturbation induced sway and showed a slowing in voluntary, as opposed to reflexive mechanisms of correcting postural disturbance. For both age groups, reflexive mechanisms were found to be relatively intact. When small perturbations were given, the elderly persons swayed more than young participants and produced sporadic reflexive activity. Moreover, elderly persons did not adapt to the small perturbations and exhibited increased postural sway to repetitive presentation of the perturbation, whereas young participants substantially decreased their postural sway. These data demonstrate that elderly persons are at some disadvantage when posture is under the control of slower, higher level sensory integrative mechanisms.

Postural Control Adaptability to Floor Oscillation in the Elderly

“…It has been reported that postural control adaptability under unusual conditions of sensory stimulation is markedly decreased in elderly subjects Woollacott et al, 1986;Stelmach et al, 1989;Allison et al, 2006). Moreover, the literature also suggests that the cerebellum and basal ganglia are closely involved in postural control adaptability (Traub et al, 1980;Chong et al, 1999;Earhart et al, 2002;Rocchi et al, 2002).…”

“…From the perspective of equilibrium training to prevent falls, evaluating postural control adaptability in the elderly is extremely important. Although it has been reported that adaptability of postural control to new environmental contexts is impaired in the elderly Woollacott et al, 1986;Stelmach et al, 1989;Allison et al, 2006), the relationship of this deterioration to increasing age and to gender has not been investigated systematically. Nashner (1976) observed an adaptive adjustment, involving the gradual reduction of response in the stretched triceps surae, in standing subjects exposed to repeated toe-up floor inclinations.…”

Deficient limb support is a major contributor to age differences in falling

“…Increased fall risk in older adults has been attributed to a variety of sensory, motor, cognitive, environmental, and medical factors (Moreland et al, 2003;Myers et al, 1996;Northridge et al, 1995). In particular, many aging-related changes in the postural responses used to maintain and regain balance have been identified McIlroy and Maki, 1996;Mille et al, 2003;Stelmach et al, 1989). However, the mechanisms whereby older adults actually fall following a loss of balance have been little investigated (Lockhart et al, 2003;Pavol et al, 2001;Pijnappels et al, 2005).…”

Association between sensorimotor function and functional and reactive balance control in the elderly

“…This aspect of balance control can be tested by inducing body sway in standing subjects by sudden support surface translation [10,11]. Changes in postural responses following support surface translation were found to occur with ageing and could possibly lead to delayed, insufficient or inappropriate attempts at balance recovery [12][13][14][15][16]. However, in addition to older adults, altered reactive postural responses have also been observed in healthy young adults who were experimentally deprived of normal somatosensory function, and in patients with vestibular dysfunction or peripheral neuropathy [14,15,17,18].…”