Haptic anchoring and human postural control.

Abstract

Several studies have emphasized the contribution of haptic input that results from the use of rigid and non-rigid tools to the postural control system. Experimental protocols such as the light touch and the anchor system are based on individuals' haptic exploration of the environment through direct tactile-kinesthetic contact, or indirectly through rigid or flexible tools that are attached to the body. In this article, we introduce the main findings of humans' haptic use of non-rigid tools during postural control tasks. We illustrate the effects of an anchor system paradigm on the maintenance of stability via haptic information. Haptic anchoring includes the handling of flexible cables that are attached to loads that are in contact with a surface. We include results of studies about haptic information gathered during the holding of a walking dog's leash. Studies that used the anchor system demonstrated its effectiveness in reducing body sway in several groups, including young adults, children, older individuals, and intellectually disabled individuals. We discuss several experimental designs and intervention protocols in order to illustrate how haptic anchoring could prompt functional plasticity.

Task difficulty has no effect on haptic anchoring during tandem walking in young and older adults

“…During proper use of the anchors, the cable should be kept taut and the mass should touch the ground at all times. In balancing tasks, the dynamic interplay between the cables' varying tensions and the continuous hand-pulling adjustments and body oscillations is the source of the haptic input that the postural system integrates in order to reduce body sway [10]. The anchors provide information about spatial orientation of the body relative to the ground, which helps to maintain the trunk in the upright position [7,10].…”

“…In balancing tasks, the dynamic interplay between the cables' varying tensions and the continuous hand-pulling adjustments and body oscillations is the source of the haptic input that the postural system integrates in order to reduce body sway [10]. The anchors provide information about spatial orientation of the body relative to the ground, which helps to maintain the trunk in the upright position [7,10]. Information, in this case, is understood as a pattern of a continuous flow of energy that specifies the environment's constraints to the individual [10].…”

“…The anchors provide information about spatial orientation of the body relative to the ground, which helps to maintain the trunk in the upright position [7,10]. Information, in this case, is understood as a pattern of a continuous flow of energy that specifies the environment's constraints to the individual [10].…”

“…In that study, we suggested that this limitation in transfer effect could be the result of the walking task's low level of difficulty. Benefits of the anchors are less evident during the practice of simple postural tasks (e.g., standing with feet apart) as compared to tasks that challenged balance control (e.g., standing with one foot, with feet together, or with eyes closed) [10,17]. Our previous study [7] showed that tandem walking in a straight line on level ground was not challenging enough for the participants to exploit the additional haptic input provided by the anchors, although this task caused destabilization of their posture.…”

A contribuição do sistema âncora em diferentes segmentos corporais para o controle da postura em idosos

“…Older adults have an increased body sway when they stand upright 4 , especially when the body support base is reduced 3 . Body sway in older adults may be reduced by adding sensory information 5,6 . Adding haptic information by fingertip light touch (<1N) of a hard or non-hard surface decreases body sway in young and older adults [7][8][9] .…”