Postural orientation and equilibrium: what do we need to know about neural control of balance to prevent falls?

Abstract

Postural control is no longer considered simply a summation of static reflexes but, rather, a complex skill based on the interaction of dynamic sensorimotor processes. The two main functional goals of postural behaviour are postural orientation and postural equilibrium. Postural orientation involves the active alignment of the trunk and head with respect to gravity, support surfaces, the visual surround and internal references. Sensory information from somatosensory, vestibular and visual systems is integrated, and the relative weights placed on each of these inputs are dependent on the goals of the movement task and the environmental context. Postural equilibrium involves the coordination of movement strategies to stabilise the centre of body mass during both self-initiated and externally triggered disturbances of stability. The specific response strategy selected depends not only on the characteristics of the external postural displacement but also on the individual's expectations, goals and prior experience. Anticipatory postural adjustments, prior to voluntary limb movement, serve to maintain postural stability by compensating for destabilising forces associated with moving a limb. The amount of cognitive processing required for postural control depends both on the complexity of the postural task and on the capability of the subject's postural control system. The control of posture involves many different underlying physiological systems that can be affected by pathology or sub-clinical constraints. Damage to any of the underlying systems will result in different, context-specific instabilities. The effective rehabilitation of balance to improve mobility and to prevent falls requires a better understanding of the multiple mechanisms underlying postural control.

Relationship between functional vision and balance and mobility performance in community-dwelling older adults

“…These results are consistent with the findings of previous studies in which depression (Iliffe et al 2005) and cognitive decline (Lin et al 2004) were more prevalent among older adults with poor functional vision. Thus, strategies to compensate for the effects of vision impairment were more limited among persons with poor functional vision (Horak 2006). This idea suggests that the role of vision in balance and mobility performance may become even more critical in old age when health problems tend to accumulate.…”

Psychometric properties of Brief‐Balance Evaluation Systems Test (Brief‐BESTest) in evaluating balance performance in individuals with chronic stroke

“…Balance control involves many subsystems (Horak, 2006). However, common clinical balance measures such as the Functional Reach Test and Single Leg Stance, are single‐task measurements which could not assess multiple domains of balance and thus have limited value in directing treatment.…”

Comparison of postural balance between professional tae kwon do athletes and young adults

“…Techniques such as kicks, jumps and quick changes in any directions trainee the sensory and motor systems of these athletes for new adaptations of postural control. Biomechanically speaking, balance is defined as the capacity of an individual to place his/her center of mass of the body, corresponding to the projection of his/her center of gravity, within his/her support base [5][6][7] . This process is complex and based on postural control from stimulus and responses derived of three systems: visual, vestibular, and somatosensory 8 .…”