The effect of advanced age and stool modification on reaching distance in sitting.

[Purpose] Reaching is an important functional ability. We investigated the effect of advanced age and stool modification on sitting reach distance. [Participants and Methods] Twenty-four participants (twelve older adults 70 ± 4 years and twelve young adults 29 ± 4 years) reached forward and laterally while sitting on an adjustable stool with 0°, 10° forward, 10° backward, 10° right or 10° left inclination of the seat, with and without footrest and front, back or side leg support.

Single session of direction-specific training using auditory cues improves anticipatory postural adjustments to lateral perturbations.

When exposed to a predictable external perturbation, humans typically generate anticipatory postural adjustments (APAs) to minimize potential body disturbance. After a single session of training, individuals demonstrated the ability to rely solely on an auditory cue to elicit appropriate APAs in response to an external postural perturbation. However, whether the generation of APAs requires directional specific training remains unclear.

The effect of a contralateral foot touch on stability of one-leg stance in young adults: an exploratory study.

Purpose: Previous studies demonstrated that providing light finger touch to a stationary object leads to reduced body sway. The focus of the current exploratory study was on the investigation of postural sway during one-leg stance when light touch is provided by the contralateral foot.

Methods: Eleven healthy young adults participated in the study.

The Effect of Additional Leg Supports in Control of Posture in Sitting.

The objective of the study was to investigate the effect of leg supports on the anticipatory and compensatory postural adjustments of sitting subjects exposed to external perturbations in the anterior-posterior direction. Ten young participants received perturbations applied to the upper body while sitting on a stool with an anterior or posterior leg support and when using a footrest. Electromyographic activities of the trunk and leg muscles and center of pressure displacements were recorded and analyzed during the anticipatory and compensatory phases of postural control.

The feasibility of using an auditory cue to elicit anticipatory postural adjustments for a posterior perturbation.

When humans are exposed to a predictable external perturbation, they usually generate anticipatory postural adjustments (APAs), which reduce the effect of potential body disturbance. However, when an external perturbation comes from behind and as such unpredicted, no APAs are generated, which challenges postural control. The aim of this study was to examine whether humans exposed to unpredictable perturbations could generate APAs using an auditory cue.

Older adults utilize less efficient postural adaptations when they are uncertain about the magnitude of a perturbation.

People frequently experience perturbations while standing or walking in crowded areas or when interacting with external objects. Balance maintenance in response to a perturbation is affected by the predictability of the magnitude of a body disturbance. The aim of this quasi-experimental study was to investigate the role of aging in maintenance of standing balance in response to perturbations of varying magnitudes.

The effect of the predictability of perturbation magnitudes in older adults with mild cognitive impairment.

Balance impairment is common in older adults with mild cognitive impairment (MCI). The ability to predict the magnitude of the body disturbance is essential to balance maintenance. The purpose of the study was to investigate the effect of the predictability of the perturbation magnitudes on anticipatory (APAs) and compensatory (CPAs) postural adjustments in older adults with MCI and healthy older adults.

Older adults can rely on an auditory cue to generate anticipatory postural adjustments prior to an external perturbation.

To minimize the potential postural disturbance induced by predictable external perturbations, humans generate anticipatory postural adjustments (APAs) using visual information about a perturbation. However, it is unknown whether older adults can generate APAs relying on auditory information. Ten older adults received external perturbations (a) with visual information but no auditory information available, (b) without neither visual nor auditory information, (c) with both visual and auditory information available, and (d) participated in training with only auditory information available.

Perturbation-based training enhances anticipatory postural control in individuals with chronic stroke: a pilot study.

Individuals with stroke commonly have impaired balance control. The aim of this study was to investigate the effect of targeted intervention on anticipatory postural adjustments (APAs) and postural control in people with stroke. Six participants with unilateral hemiparesis due to a stroke (5.

The Effect of Predictability of the Perturbation Magnitude on Anticipatory and Compensatory Postural Adjustments during a Bimanual Load-Lifting Task.

To minimize the potential postural disturbance induced by external or self-initiated perturbations, humans generate anticipatory postural adjustments based on their perceived consequences of the body disturbance. Lifting is a common activity that induces a self-initiated perturbation that can compromise balance control. To assess anticipatory (APAs) and compensatory (CPAs) postural adjustments generated in response to a self-initiated perturbation induced by lifting objects of uncertain mass.

Reaching in sitting: The effect of seat design and body manipulations.

Background: Sitting is a common and familiar position used daily as a platform for many motor activities in the workplace, at school, or at home.

Objective: To investigate how difference in the chair design and selected sitting manipulations contribute to reach distance in sitting.

Methods: Ten healthy subjects were required to reach forward as far as possible while sitting in an adjustable chair with 0°, 10° forward or 10° backward inclination of the seat, with and without footrest and leg support, with legs crossed, and when holding the edge of the seat with the contralateral arm.

The Role of Predictability of Perturbation in Control of Posture: A Scoping Review.

Efficient maintenance of posture depends on the ability of humans to predict consequences of a perturbation applied to their body. The purpose of this scoping review was to map the literature on the role of predictability of a body perturbation in control of posture. A comprehensive search of MEDLINE, EMBASE, and CINAHL databases was conducted.

Perceptual distortion in virtual reality and its impact on dynamic postural control.

Background: Voluntary movement such as lifting a foot in preparation to stepping acts as a self-initiated perturbation that disturbs postural equilibrium. To maintain and restore equilibrium, humans utilize early, anticipatory, and compensatory postural adjustments. Despite technological progress in accessible virtual reality (VR) devices, little is known on the usage of VR in control and maintenance of balance while standing.

Role of angular position of the seat in control of posture in response to external perturbation.

Ability of the human body to regain balance after being externally perturbed is important in the maintenance of vertical posture. The goal of this study was to investigate trunk and leg muscle response to external perturbation while sitting on a stool with varying seat inclinations. Ten healthy subjects were required to receive a perturbation applied to the upper body while sitting on an adjustable stool with 0°, 10° forward or 10° backward inclination of the seat and without footrest and leg support.

The role of predictability of the magnitude of a perturbation in control of vertical posture when catching an object.

The predictability of perturbation magnitude plays an important role in control of standing posture. The aim of the study was to examine anticipatory (APAs) and compensatory (CPAs) postural adjustments in response to catching objects of uncertain mass. Twenty adults caught the same object with either light or heavy weight placed in it.

Enhancement of balance, and mobility in individuals with multiple sclerosis using visual cue guided multidirectional step training - A pilot study.

Background: Individuals with multiple sclerosis (MS) often experience limitations in mobility due to impairment of gait and balance. Rehabilitation approaches to improve balance and mobility in individuals with MS are limited. We have developed a novel visual cue guided multi-direction step (MDS) training method to improve balance and mobility in individuals with MS.

The effect of a textured insole on anticipatory postural adjustments.

Purpose: To obtain preliminary data on the effect of a textured insole on postural control.

Methods: Nine healthy subjects were exposed to external perturbations applied to their shoulders while standing with or without a single textured insole. Body weight distribution and bilateral electromyographic activity (EMG) of trunk and leg muscles were recorded.

Effect of predictability of the magnitude of a perturbation on anticipatory and compensatory postural adjustments.

Balance maintenance in response to a perturbation could be affected by the predictability of the magnitude of the body disturbance. We investigated anticipatory (APAs) and compensatory (CPAs) postural adjustments in response to perturbations of predictable and unpredictable magnitudes. Twenty young adults received series of perturbations of small or large magnitudes the order of which was varied.

Effect of Light Finger Touch, a Cognitive Task, and Vision on Standing Balance in Stroke.

The aim of the exploratory study was to investigate the individual and combined effects of light finger touch, a cognitive task, and vision on postural sway in individuals with stroke. Nine older adults with stroke stood on the force platform with eyes open and eyes closed, with and without a light finger touch contact with the stationary frame, and when counting backward from a randomly chosen three-digit number or without it. The center of pressure (COP) excursion, velocity, range and sway area was calculated.

The role of an auditory cue in generating anticipatory postural adjustments in response to an external perturbation.

Anticipatory postural adjustments (APAs) are usually generated to minimize the potential postural disturbance induced by predictable external perturbations. Visual information about a perturbation is important for the generation of APAs, but whether people can rely on auditory information to generate APAs is unknown. The aim of this study was to investigate the role of an auditory cue in generating APAs when visual information is not available.

Individuals with stroke improve anticipatory postural adjustments after a single session of targeted exercises.

Impairment of anticipatory postural adjustments (APAs) is an important source of postural instability in older adults and individuals with neurological disorders. The aim of the study was to investigate whether APAs could be improved in people with stroke as a result of targeted exercise involving their unaffected upper extremity. Nine individuals with stroke and five healthy control individuals participated in the laboratory tests before and after a single session of practice consisting of pushing a medicine ball attached to the ceiling and stopping the ball with their palm when it returns.

Effects of Ankle Angular Position and Standing Surface on Postural Control of Upright Stance.

The purpose of the study was to investigate the effects of ankle angular position and standing surface type on static upright balance. Ten young adults stood on a force platform or on a firm wedge that induced 15° of either dorsiflexion or plantarflexion. In addition, a piece of foam was placed on top of the force platform and on the wedge.

Role of a single session of ball throwing exercise on postural control in older adults with mild cognitive impairment.

Purpose: The purpose of the study was to investigate the role of training in improvement of balance control in older adults with mild cognitive impairment.

Methods: Older adults (mean age 78) with mild cognitive impairment (MCI) and cognitively intact older adults (mean age 72) were exposed to self-initiated perturbations while performing bilateral shoulder flexion task before and after a single training session consisting of throwing a medicine ball. EMG activity of six trunk and lower limb muscles was recorded.

Characteristics of medial-lateral postural control while exposed to the external perturbation in step initiation.

Controllability of posture in the medial-lateral direction is critical for balance maintenance, particularly in step initiation. The objective of the current study was to examine  the effects of external perturbation and landing orientation on medial-lateral control stability in step initiation. Eleven young healthy participants stood on the force platform and waited for the instruction of taking a step while experiencing a pendulum perturbation applied at the lateral side of the right shoulder.