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Introduction: Plantar cutaneous augmentation is a promising approach in balance rehabilitation by enhancing motion-dependent sensory feedback. The effect of plantar cutaneous augmentation on balance has been mainly investigated in its passive form (e.g., textured insole) or on lower-limb amputees. In this study, we tested the effect of plantar cutaneous augmentation on balance in its active form (i.e., electrical stimulation) for individuals with intact limbs., Methods: Ten healthy subjects participated in the study and were instructed to maintain their balance as long as possible on the balance board, with or without electrotactile feedback evoked on the medial side of the heel, synched with the lateral board sway. Electrotactile feedback was given in two different modes: 1) Discrete-mode E-stim as the stimulation on/off by a predefined threshold of lateral board sway and 2) Proportional-mode E-stim as the stimulation frequency proportional to the amount of lateral board sway. All subjects were distracted from the balancing task by the n-back counting task, to test subjects' balancing capability with minimal cognitive involvement., Results: Proportional-mode E-stim, along with the n-back counting task, increased the balance time from 1.86 ± 0.03 s to 1.98 ± 0.04 s ( p  = 0.010). However, discrete-mode E-stim did not change the balance time ( p  = 0.669). Proportional-mode E-stim also increased the time duration per each swayed state ( p  = 0.035) while discrete-mode E-stim did not ( p  = 0.053)., Discussion: These results suggest that proportional-mode E-stim is more effective than discrete-mode E-stim on improving standing balance. It is perhaps because the proportional electrotactile feedback better mimics the natural tactile sensation of foot pressure than its discrete counterpart., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Raghav Hari Krishna, Kim, Chang, Choe and Park.)

Accessible Summary: Multisensory stimulation improves attention, which can also improve memory and standing balance of people with learning disabilities, even at a high age.Improved standing balance and body awareness may help reduce falls in people with moderate learning disabilities.Therapeutic treatments could be more effective if preceded by multisensory stimulation. Background: The Snoezelen room provides a multisensory environment for people with learning disabilities. Method: Thirty‐five residents were recruited from a convenience sample of people living in a residential centre. A repeated‐measures, within‐subject design was used to evaluate the participants during three conditions: a) Snoezelen room, b) control period and c) watching television. The outcome measures were digit span memory tests and Romberg balance tests. One‐way repeated‐measures ANOVAs and paired‐samples t tests were performed on the data. Results: ANOVA results show that there was a significant effect over time in the amount of digits remembered and in balancing ability between the three conditions (p < .0005). T tests confirmed that the Snoezelen condition was responsible for the significant improvements in memory and balancing ability. Conclusion: Participants performed significantly better with memory tasks and balancing skills after having attended multisensory stimulation in a Snoezelen room. This may be due to improved mindfulness, which is correlated with improvements of concentration, learning ability and motor skills caused by neurophysiologic changes of the brain. [ABSTRACT FROM AUTHOR]

Background: Balance and cognitive decline are impairments in people living with HIV (PLWH). These impairments predispose to fall-related injuries, affecting health-related quality of life (HRQoL). This study assessed standing balance and cognition after a three-month fitness program and its relationship to HRQoL. Methods: Fifty-four PLWH participating in a community-based fitness program participated in this study. Standing balance with eyes open and eyes closed was measured with a pressure mat. Cognition was assessed using the HIV dementia scale (HDS), while the Functional Assessment of HIV Infection (FAHI) was used as a measure of HRQoL. Paired t-tests compared balance values while linear regression explored the association between balance and HDS scores with HRQoL. Results: Balance values with eyes open improved significantly (p=0.04). Linear regression showed a significant association between the three predictors and HRQoL (r = .50; p = .017). Conclusions: Standing balance and mental status play a significant role in HRQoL in PLWH. [ABSTRACT FROM AUTHOR]

In human quiet standing, the relative position between ankle joint centre and line of gravity is neurally regulated within tight limits. The regulation of the knee and hip configuration is unclear and thought to be controlled passively. However, perturbed standing experiments have shown a lower limb multi-joint coordination. Here, measuring the relative alignment between lower limb joints and the line of gravity in quiet standing after walking, we investigated whether the configuration is maintained over time through passive mechanisms or active control. Thirteen healthy adults walked without following a path and then stood quietly for 7.6 s on a force platform (up to four trials). The transition between initiation and steady-state standing (7.6 s) was measured using motion capture. Sagittal lower limb joint centres' position relative to line of gravity (CoGAP) and their time constants were calculated in each trial. Ankle, knee, and hip joint moments were also calculated through inverse dynamics. After walking, the body decelerated (τ = 0.16 s). The ankle and hip joints' position relative to CoGAP measured at two time intervals of quiet standing (Mid = 0.5–0.55 s; End = 7.55–7.6 s) were different (mean ± SEM, CoGAP–Ankle_Mid = 47 ± 4 mm, CoGAP–Ankle_End = 58 ± 5 mm; CoGAP–Hip_Mid = 2 ± 5 mm, CoGAP–Hip_End = −5 ± 5 mm). The ankle, knee, and hip flexion-extension moments significantly changed. Changes in joints position relative to CoGAP and misalignment suggest that joint position is not maintained over 7.6 s, but regulated relative to a standing reference. Higher joint moments at steady-state standing suggest mechanisms other than passive knee and hip regulation are involved in standing. [ABSTRACT FROM AUTHOR]

Objective: The present investigation was designed to examine if high-resolution music box audio influences postural stability. Design: A clinical study. Materials and Methods: 21 healthy young adults were instrumented for the measurement of stabilometry (Twin Gravicorder G-5500, Anima Co. Ltd.). They were exposed to high-resolution music box audio. Results: Total locus length of both leg stand with eye open significantly decreased with exposure of high-resolution music box audio (p = 0.034). Total locus length of both leg stand decreased with exposure of high-resolution music box audio than that of high-cut music box audio (p = 0.316). Conclusions: Our study suggests that high-resolution music box audio improved balance ability and that high-resolution music box audio reduces the incidence of falls. [ABSTRACT FROM AUTHOR]

Supplemental Digital Content is Available in the Text. Background and Purpose: Trunk control is important for maintaining balance; hence, deficient trunk control may contribute to balance problems in people with Parkinson disease (PD). Unfortunately, this deficit is poorly managed with pharmacological therapies, emphasizing the need for alternative therapies for these patients. This randomized controlled trial sought to examine the effects of a 12-week trunk-specific exercise-based intervention on balance in people with PD. Methods: Twenty-four people with PD and with a history of falls completed assessments of motor symptom severity, balance confidence, mobility, quality of life, and quiet-standing balance. Participants were then randomized to receive either 12 weeks of exercise or education and reassessed after 12 and 24 weeks. Results: Linear mixed-models analyses showed no significant changes in clinical outcomes following the intervention. However, during quiet standing, sway area on a foam surface without vision was reduced for the exercise group at 12 (−6.9 ± 3.1 cm; 95% confidence interval [CI] = −13.1 to −0.7; P = 0.029; d = 0.66) and 24 weeks (−7.9 ± 3.1 cm; 95% CI = −14.1 to −1.7; P = 0.013; d = 0.76). Furthermore, the exercise group demonstrated reduced sway variability at 12 (−0.2 ± 0.1 cm; 95% CI = −0.4 to 0.0; P = 0.042; d = 0.62) and 24 weeks in the medial-lateral direction (−0.2 ± 0.1 cm; 95% CI = −0.4 to 0.0; P = 0.043; d = 0.62). No changes in quiet standing balance were recorded for the education group. Discussion and Conclusions: The results of this study suggest that exercise-based interventions targeting trunk strength, endurance, and mobility may be effective for improving quiet-standing balance in people with PD. However, additional research is needed to determine whether these improvements are sufficient to reduce falls risk. Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A254). [ABSTRACT FROM AUTHOR]

Background: Assessing traditional neuromuscular fall risk factors (i.e., balance, gait, strength) in the elderly has so far mainly been done independently. Functional and integrative testing approaches are scarce. The present study proposes an agility course for an integrative assessment of neuromuscular and also cardiocirculatory capacity in seniors – and tests its criterion validity and reliability. Methods: Thirty-six seniors (age: 69.0 ± 2.8 years; BMI: 25.4 ± 3.5 kg/m2; sex: 19 males/17 females; weekly physical activity: 9.4 ± 5.5 h) participated. They completed four trials of the Agility Challenge for the Elderly (ACE)-course in two sessions separated by 1 week. The course consists of three segments focusing on different agility aspects. Cardiovascular capacity was assessed by 6-min walk test (6MWT), neuromuscular capacity by static, dynamic and perturbed standing balance tasks, habitual gait speed assessment, and rate of torque development testing. Parameters' predictive strength for the ACE performance was assessed by regression analysis. Reliability was calculated with intraclass correlation coefficients and coefficients of variation. Results: Men completed the course in 43.0 ± 5.7 s and women in 51.9 ± 4.0 s. Overall and split times were explained by 6MWT time ( η p 2 = 0.38–0.44), gait speed ( η p 2 = 0.29–0.43), and to a lesser extent trunk rotation explosive strength ( η p 2 = 0.05–0.12). Static and dynamic balance as well as plantar flexion strength explained the performance in some segments to a very small extent ( η p 2 = 0.06–0.08). Good between- and within-day reliability were observed for total course and split times: The ICC for the between-day comparison was 0.93 (0.88–0.96) and ranged between 0.84 and 0.94 for split times. The within-day ICC was 0.94 (0.91–0.97) for overall time and 0.92–0.97 for split times. Coefficients of variation were smaller than 5.7% for within and between day analyses. Conclusion: The ACE course reflects cardiocirculatory and neuromuscular capacity, with the three ACE segments potentially reflecting slightly different domains of neuromuscular (static and dynamic balance, ankle, and trunk strength) performance, whereas cardiocirculatory fitness and gait speed contribute to all segments. Our test can detect changes in overall performance greater than 5.7% and can thus be useful for documenting changes due to interventions in seniors. [ABSTRACT FROM AUTHOR]

Introduction: Bad posture is a well-known problem in children and adolescents, and it has a negative effect in adulthood. It can be hypothesized that due to bad posture, changes in the body’s position cause changes in standing balance. Objective: The objective of the study is to determine the influence of bad posture on the standing balance of school-aged children based on independent time–distance- and frequency-based foot centre-of-pressure parameters. Subjects and Methods: Subjects included 171 children (113 with neutral posture (70 boys and 73 girls), mean age: 10.7 ± 1.1 years (range: 9–13), and 68 with bad posture (22 boys and 46 girls), mean age: 10.7 ± 1.2 (range: 9–13)). The parameters were derived from the motion of the centre of pressure on a platform equipped with pressure sensors, on which the subjects were standing for 60 s with both feet and open eyes. Results: When comparing the two groups, the load distribution difference between the legs and the medium–high-frequency band power ratio in the mediolateral direction showed a significant difference out of 17 centre-of-pressure parameters. However, the other 15 parameters did not show any significant differences. Conclusion: There is no clearly significant degradation of postural control in children with bad posture, as the effects of altered posture are continuously corrected by the central nervous system. The asymmetric load between the two sides may further degrade muscular imbalance; thus, correcting bad posture is an important task of physiotherapy.

Background: While standing upright, the brain must accurately accommodate for delays between sensory feedback and self-generated motor commands. Natural aging may limit adaptation to sensorimotor delays due to age-related decline in sensory acuity, neuromuscular capacity and cognitive function. This study examined balance learning in young and older adults as they stood with robot-induced sensorimotor delays., Methods: A cohort of community dwelling young (mean = 23.6 years, N  = 20) and older adults (mean = 70.1 years, N  = 20) participated in this balance learning study. Participants stood on a robotic balance simulator which was used to artificially impose a 250 ms delay into their control of standing. Young and older adults practiced to balance with the imposed delay either with or without visual feedback (i.e., eyes open or closed), resulting in four training groups. We assessed their balance behavior and performance (i.e., variability in postural sway and ability to maintain upright posture) before, during and after training. We further evaluated whether training benefits gained in one visual condition transferred to the untrained condition., Results: All participants, regardless of age or visual training condition, improved their balance performance through training to stand with the imposed delay. Compared to young adults, however, older adults had larger postural oscillations at all stages of the experiments, exhibited less relative learning to balance with the delay and had slower rates of balance improvement. Visual feedback was not required to learn to stand with the imposed delay, but it had a modest effect on the amount of time participants could remain upright. For all groups, balance improvements gained from training in one visual condition transferred to the untrained visual condition., Conclusion: Our study reveals that while advanced age partially impairs balance learning, the older nervous system maintains the ability to recalibrate motor control to stand with initially destabilizing sensorimotor delays under differing visual feedback conditions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Rasman, van der Zalm and Forbes.)

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Copyright of Rigakuryoho Kagaku is the property of International Press Editing Center Incorporation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Maintaining standing balance involves multisensory processing and integration to produce dynamic motor responses. Electrical vestibular stimulation (EVS) delivered over the mastoid processes can be used to explore the vestibular control of balance. The purpose of this study was to determine whether intrinsic foot muscles exhibit vestibular-evoked balance responses and to characterize the traits associated with these responses. Electromyography (EMG) of the abductor hallucis (AH), abductor digiti minimi (ADM) and medial gastrocnemius (MG) and anterior–posterior (AP) forces were sampled while quietly standing participants were subjected to a random continuous EVS signal (peak-to-peak amplitude = ±3 mA). The relationship between EVS input and motor output was characterized in both the frequency (coherence) and time (cumulant density) domains. When head orientation was rotated in yaw from left to right, the biphasic cumulant density function was inverted for all muscle (EVS–EMG) and whole-body (EVS–AP forces) balance responses. When vision was occluded, the EVS–EMG and EVS–AP forces coherence function amplitude increased at low frequencies (<2 Hz) and was accompanied by a heightened medium-latency peak amplitude for all muscles as well as the whole-body balance response (AP forces) compared to when static visual cues were present. The enhanced coherence amplitudes at lower frequencies may highlight a mechanism for the increase in postural sway from vision to occluded vision. The current findings indicate that the vestibular control of standing balance can be represented by the intrinsic foot muscles and implicate a postural role for these muscles in modulating quiet standing. [ABSTRACT FROM AUTHOR]

Human maintain their body balance by sensorimotor controls mainly based on information gathered from vision, proprioception and vestibular systems. When there is a lack of information, caused by pathologies, diseases or aging, the subject may fall. In this context, we developed a system to augment information gathering, providing the subject with warning audio-feedback signals related to his/her equilibrium. The system comprises an inertial measurement unit (IMU), a data processing unit, a headphone audio device and a software application. The IMU is a low-weight, small-size wireless instrument that, body-back located between the L2 and L5 lumbar vertebrae, measures the subject's trunk kinematics. The application drives the data processing unit to feeding the headphone with electric signals related to the kinematic measures. Consequently, the user is audio-alerted, via headphone, of his/her own equilibrium, hearing a pleasant sound when in a stable equilibrium, or an increasing bothering sound when in an increasing unstable condition. Tests were conducted on a group of six older subjects (59y-61y, SD = 2.09y) and a group of four young subjects (21y-26y, SD = 2.88y) to underline difference in effectiveness of the system, if any, related to the age of the users. For each subject, standing balance tests were performed in normal or altered conditions, such as, open or closed eyes, and on a solid or foam surface. The system was evaluated in terms of usability, reliability, and effectiveness in improving the subject's balance in all conditions. As a result, the system successfully helped the subjects in reducing the body swaying within 10.65%-65.90%, differences depending on subjects’ age and test conditions. [ABSTRACT FROM AUTHOR]

The purpose of the study was to investigate the individual and combined effects of applying light finger touch and performing a cognitive task on postural sway. Fourteen healthy young individuals stood on the force platform with light finger touch contact applied to an external stable structure and without finger touch. Both tasks were performed with and without a cognitive task (counting backward from a randomly chosen three-digit number). The center of pressure excursion and velocity as well as sway area were calculated. Participants demonstrated significantly smaller postural sway in the presence of a finger touch contact (p < 0.05), while postural sway was increased during the performance of the cognitive task (p < 0.05). When two tasks were performed simultaneously, body sway increased as compared to standing with light touch only (p < 0.05) and decreased when compared to standing and performing the cognitive task only (p < 0.05). This suggests that a positive effect of finger touch on body sway could be diminished by the simultaneous performance of a cognitive task. The outcome provides a foundation for future studies of the individual and combined effects of light finger touch and cognitive tasks on postural control. [ABSTRACT FROM AUTHOR]

This study systematically explored the potential of applying feedback control of functional neuromuscular stimulation (FNS) for stabilizing various erect and leaning standing postures after spinal cord injury (SCI). Perturbations ranging from 2 to 6% body weight were applied to two subjects with motor complete thoracic level SCI who were proficient at standing with implanted multichannel neural stimulators to activate the ankle, knee, hip and trunk muscles. The subjects stood with four different postures: erect, forward, forward-right and forward-left. Repeatable and controlled perturbations were applied in the forward, backward, rightward and leftward directions by linear actuators pulling on ropes attached to the subjects via a belt worn just above the waist. Upper extremity (UE) forces exerted on a stationary walker were measured with load cells attached to the handles. A feedback controller based on center of pressure (CoP) varied the stimulation levels to the otherwise paralyzed muscles so as to resist the effects of the perturbations. The effect of the feedback controller was compared to the case where only open-loop baseline stimulation was applied. This was done in terms of: (a) maximum resultant UE force exerted by the subjects on the walker, (b) maximum resultant CoP overshoot and (c) CoP root-mean-square deviation (RMSD). Feedback control resulted in significant reductions in the mean values of the majority of outcome values compared to baseline open-loop stimulation. Maximum resultant UE force was reduced by as much as 50% in one of the postures for one of the subjects. RMSD and maximum CoPs were reduced by as much as 75 and 70%, respectively, with feedback control. These results indicate that feedback control can be used to reject destabilizing disturbances in individuals with SCI using FNS not only for erect postures but also for leaning postures typically adopted during reaching while attempting various activities of daily living. [ABSTRACT FROM AUTHOR]

Background: Orthostatic hypotension (OH), a blood pressure drop after postural change, is associated with impaired standing balance and falls in older adults. This study aimed to assess the association between blood pressure (BP) and a measure of quality of standing balance, i.e. Center of Pressure (CoP) movement, after postural change from supine to standing position in geriatric outpatients, and to compare CoP movement between patients with and without OH.Methods: In a random subgroup of 75 consecutive patients who were referred to a geriatric outpatient clinic, intermittent BP measurements were obtained simultaneously with CoP measurements in mediolateral and anterior-posterior direction directly after postural change during 3 min of quiet stance with eyes open on a force plate. Additional measurements of continuous BP were available in n = 38 patients. Associations between BP change during postural change and CoP movement were analyzed using Spearman correlation. Mann-Whitney-U tests were used to compare CoP movement between patients with OH and without OH, in which OH was defined as a BP drop exceeding 20 mmHg of systolic BP (SBP) and/or 10 mmHg of diastolic BP (DBP) within 3 min after postural change.Results: OH measured intermittently was found in 8 out of 75 (11%) and OH measured continuously in 22 out of 38 patients (57.9%). BP change did not associate with CoP movement. CoP movement did not differ significantly between patients with and without OH.Conclusions: Results do not underpin the added value of CoP movement measurements in diagnosing OH in a clinical setting. Neither could we identify the role of CoP measurements in the understanding of the relation between OH and impaired standing balance. [ABSTRACT FROM AUTHOR]

Haptic cues are important for balance. Knowledge of the temporal features of their effect may be crucial for the design of neural prostheses. Touching a stable surface with a fingertip reduces body sway in standing subjects eyes closed (EC), and removal of haptic cue reinstates a large sway pattern. Changes in sway occur rapidly on changing haptic conditions. Here, we describe the effects and time-course of stabilization produced by a haptic cue derived from a walking cane. We intended to confirm that cane use reduces body sway, to evaluate the effect of vision on stabilization by a cane, and to estimate the delay of the changes in body sway after addition and withdrawal of haptic input. Seventeen healthy young subjects stood in tandem position on a force platform, with eyes closed or open (EO). They gently lowered the cane onto and lifted it from a second force platform. Sixty trials per direction of haptic shift (Touch → NoTouch, T-NT; NoTouch → Touch, NT-T) and visual condition (EC-EO) were acquired. Traces of Center of foot Pressure (CoP) and the force exerted by cane were filtered, rectified, and averaged. The position in space of a reflective marker positioned on the cane tip was also acquired by an optoelectronic device. Cross-correlation (CC) analysis was performed between traces of cane tip and CoP displacement. Latencies of changes in CoP oscillation in the frontal plane EC following the T-NT and NT-T haptic shift were statistically estimated. The CoP oscillations were larger in EC than EO under both T and NT (p < 0.001) and larger during NT than T conditions (p < 0.001). Haptic-induced effect under EC (Romberg quotient NT/T ~ 1.2) was less effective than that of vision under NT condition (EC/EO ~ 1.5) (p < 0.001). With EO cane had little effect. Cane displacement lagged CoP displacement under both EC and EO. Latencies to changes in CoP oscillations were longer after addition (NT-T, about 1.6 s) than withdrawal (T-NT, about 0.9 s) of haptic input (p < 0.001). These latencies were similar to those occurring on fingertip touch, as previously shown. Overall, data speak in favor of substantial equivalence of the haptic information derived from both “direct” fingertip contact and “indirect” contact with the floor mediated by the cane. Cane, finger and visual inputs would be similarly integrated in the same neural centers for balance control. Haptic input from a walking aid and its processing time should be considered when designing prostheses for locomotion.

It is well established that somatosensory inputs to the cortex undergo an early and a later stage of processing. The later has been shown to be enhanced when the earlier transmission decreased. In this framework, mechanical factors such as the mechanical stress to which sensors are subjected when wearing a loaded vest are associated with a decrease in sensory transmission. This decrease is in turn associated with an increase in the late sensory processes originating from cortical areas. We hypothesized that unweighting the plantar sole should lead to a facilitation of the sensory transmission. To test this hypothesis, we recorded cortical somatosensory evoked potentials (SEPs) of individuals following cutaneous stimulation (by mean of an electrical stimulation of the foot sole) in different conditions of unweighting when standing still with eyes closed. To this end, the effective bodyweight (BW) was reduced from 100% BW to 40% BW. Contrary to what was expected, we found an attenuation of sensory information when the BW was unweighted to 41% which was not compensated by an increase of the late SEP component. Overall these results suggested that the attenuation of sensory transmission observed in 40 BW condition was not solely due to the absence of forces acting on the sole of the feet but rather to the current relevance of the afferent signals related to the balance constraints of the task.

Tzu-Hsuan Chen,1,* Li-Wei Chou,2,3,* Mei-Wun Tsai,4 Ming-Jor Lo,5 Mu-Jung Kao4,5 1Department of Rehabilitation, Mackay Memorial Hospital, Hsinchu, Taiwan; 2Department of Physical Medicine and Rehabilitation, China Medical University Hospital, Taichung, Taiwan; 3School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung, Taiwan; 4Department of Physical Therapy and Assistive Technology, National Yang-Ming University, Taipei, Taiwan; 5Department of Rehabilitation, Yangming Branch, Taipei City Hospital, Taipei, Taiwan *These authors contributed equally to this paper Background: The use of insoles may enhance postural stability and prevent falls. The aim of this study was to design a new insole and to explore the effectiveness of the insole on the standing balance of the healthy elderly. Methods: The study was conducted at a community hospital. Patients older than 65 years at an outpatient clinic without abnormal gait patterns, lower limb deformities, or foot pain were enrolled. The participants were assigned to good- and poor-stability groups on the basis of the stability index (SI), using the Biodex® Balance System. A heel cup with an arch support insole was provided. Participants wore the insole for 8 weeks for a minimum of 4 hours/day. A static balance test for SI was performed at the initial meeting and 8 weeks after the assigned insoles were worn for each participant. Results: Five participants (10.0%) of 50 total did not finish the study. There were 25 patients in the good-stability group and 20 in the poor-stability group. The SI, before and after intervention, was significantly different for all 45 participants (3.244±0.688 versus 3.064±0.671; P

Haptic cues are important for balance. Knowledge of the temporal features of their effect may be crucial for the design of neural prostheses. Touching a stable surface with a fingertip reduces body sway in standing subjects eyes closed (EC), and removal of haptic cue reinstates a large sway pattern. Changes in sway occur rapidly on changing haptic conditions. Here, we describe the effects and time-course of stabilization produced by a haptic cue derived from a walking cane. We intended to confirm that cane use reduces body sway, to evaluate the effect of vision on stabilization by a cane, and to estimate the delay of the changes in body sway after addition and withdrawal of haptic input. Seventeen healthy young subjects stood in tandem position on a force platform, with eyes closed or open (EO). They gently lowered the cane onto and lifted it from a second force platform. Sixty trials per direction of haptic shift (Touch! NoTouch, T-NT; NoTouch ! Touch, NT-T) and visual condition (EC-EO) were acquired. Traces of Center of foot Pressure (CoP) and the force exerted by cane were filtered, rectified, and averaged. The position in space of a reflective marker positioned on the cane tip was also acquired by an optoelectronic device. Cross-correlation (CC) analysis was performed between traces of cane tip and CoP displacement. Latencies of changes in CoP oscillation in the frontal plane EC following the T-NT and NT-T haptic shift were statistically estimated. The CoP oscillations were larger in EC than EO under both T and NT (p < 0.001) and larger during NT than T conditions (p < 0.001). Haptic-induced effect under EC (Romberg quotient NT/T ↑ 1.2) was less effective than that of vision under NT condition (EC/EO ↑ 1.5) (p < 0.001). With EO cane had little effect. Cane displacement lagged CoP displacement under both EC and EO. Latencies to changes in CoP oscillations were longer after addition (NT-T, about 1.6 s) than withdrawal (T-NT, about 0.9 s) of haptic input (p < 0.001). These latencies were similar to those occurring on fingertip touch, as previously shown. Overall, data speak in favor of substantial equivalence of the haptic information derived from both "direct" fingertip contact and "indirect" contact with the floor mediated by the cane. Cane, finger and visual inputs would be similarly integrated in the same neural centers for balance control. Haptic input from a walking aid and its processing time should be considered when designing prostheses for locomotion. [ABSTRACT FROM AUTHOR]

Research on balance and mobility in older adults has been conducted primarily in lab-based settings in individuals who live in the community. Although they are at greater risk of falls, residents of long-term care facilities, specifically residential care communities (RCCs), have been investigated much less frequently. We sought to determine the feasibility of using portable technology-based measures of balance and muscle strength (i.e., an accelerometer and a load cell) that can be used in any RCC facility. Twenty-nine subjects (age 87 ± 6 years) living in RCCs participated. An accelerometer placed on the back of the subjects measured body sway during different standing conditions. Sway in antero-posterior and mediolateral directions was calculated. Lower extremity strength was measured with a portable load cell and the within-visit reliability was determined. Assessments of grip strength, gait speed, frailty, and comorbidity were also examined. A significant increase in postural sway in both the AP and ML directions occurred as the balance conditions became more difficult due to alteration of sensory feedback ( p < 0.001) or reducing the base of support ( p < 0.001). There was an association between increased sway and increased frailty, more comorbidities and slower gait speed. All strength measurements were highly reliable (ICC = 0.93-0.99). An increase in lower extremity strength was associated with increased grip strength and gait speed. The portable instruments provide inexpensive ways for measuring balance and strength in the understudied RCC population, but additional studies are needed to examine their relationship with functional outcomes. [ABSTRACT FROM AUTHOR]

Introduction: The Sensory Organization Test (SOT) and the Paediatric Clinical Test of Sensory Interaction for Balance (PCTSIB) quantify the ability to maintain balance in the presence of sensory conflicts. The purposes of this study were to evaluate the comparability of these two assessment tools and to explore their distribution characteristics in adolescent rhythmic gymnasts. Methods: Fifteen female rhythmic gymnasts (15.0±1.8 yr.) who had received professional training for at least nine months were assessed in a single session. There were corresponding six sensory conditions in the SOT and PCTSIB tests. The SOT equipment automatically outputs computer-generated equilibrium scores based on the participant’s sway angle, whereas the PCTSIB involves manual timing (holding time), which can be combined with observation of sway angle to generate the performance score (summary score). Results: The equilibrium scores of the SOT Conditions 1 to 6 of the rhythmic gymnasts were 95.5 ± 1.4, 93.0 ± 2.1, 93.8 ± 1.6, 89.7 ± 4.0, 62.9 ± 9.7, and 74.0 ± 8.8%, respectively. Rhythmic gymnasts’ performance in SOT Conditions 1 to 3, with firm support, revealed narrow distributions of performance and ceiling effects. Notable ceiling effects were also evident in the holding time of PCTSIB Conditions 1, 2, 3, 4 and 6, as well as in the summary score of PCTISB Conditions 1 and 4 with eyes open. Only Condition 5 of the PCTSIB (holding time) was related to the corresponding SOT condition: eyes closed with altered support (Rho = 0.61). Conclusion: Although the PCTSIB and SOT tests have similar designs, their results are not comparable, which might be due to the notable ceiling effects when the tests are applied to rhythmic gymnasts. We recommend using SOT Conditions 4 to 6 in the laboratory or PCTSIB Condition 5 (holding time) in the field to evaluate sensory organization ability in adolescent rhythmic gymnasts. [ABSTRACT FROM AUTHOR]

Objective: This study sought to evaluate the effects of a Nintendo Wii Balance Board (NWBB) intervention on ankle spasticity and static standing balance in young people with spastic cerebral palsy (SCP). Methods: Ten children and adolescents (aged 72–204 months) with SCP participated in an exercise program with NWBB. The intervention lasted 6 weeks, 3 sessions per week, 25 minutes for each session. Ankle spasticity was assessed using the Modified Modified Ashworth Scale (MMAS), and static standing balance was quantified using posturographic measures (center-of-pressure [CoP] measures). Pre- and post-intervention measures were compared. Results: Significant decreases of spasticity in the ankle plantar flexor muscles (p < 0.01). There was also a significant reduction in the CoP sway area (p = 0.04), CoP mediolateral velocity (p =0.03), and CoP anterior–posterior velocity (p = 0.03). Conclusion: A 6-session NWBB program reduces the spasticity at the ankle plantar flexors and improves the static standing balance in young people with SCP. [ABSTRACT FROM AUTHOR]

Rhythmic gymnasts specialise in dynamic balance under sensory conditions of numerous somatosensory, visual, and vestibular stimulations. This study investigated whether adolescent rhythmic gymnasts are superior to peers in Sensory Organisation test (SOT) performance, which quantifies the ability to maintain standing balance in six sensory conditions, and explored whether they plateaued faster during familiarisation with the SOT. Three and six sessions of SOTs were administered to 15 female rhythmic gymnasts (15.0 ± 1.8 years) and matched peers (15.1 ± 2.1 years), respectively. The gymnasts were superior to their peers in terms of fitness measures, and their performance was better in the SOT equilibrium score when visual information was unreliable. The SOT learning effects were shown in more challenging sensory conditions between Sessions 1 and 2 and were equivalent in both groups; however, over time, the gymnasts gained marginally significant better visual ability and relied less on visual sense when unreliable. In conclusion, adolescent rhythmic gymnasts have generally the same sensory organisation ability and learning rates as their peers. However, when visual information is unreliable, they have superior sensory organisation ability and learn faster to rely less on visual sense. [ABSTRACT FROM AUTHOR]

Background: Implanted motor system neuroprostheses can be effective at increasing personal mobility of persons paralyzed by spinal cord injuries. However, currently available neural stimulation systems for standing employ patterns of constant activation and are unreactive to changing postural demands.Methods: In this work, we developed a closed-loop controller for detecting forward-directed body disturbances and initiating a stabilizing step in a person with spinal cord injury. Forward-directed pulls at the waist were detected with three body-mounted triaxial accelerometers. A finite state machine was designed and tested to trigger a postural response and apply stimulation to appropriate muscles so as to produce a protective step when the simplified jerk signal exceeded predetermined thresholds.Results: The controller effectively initiated steps for all perturbations with magnitude between 10 and 17.5 s body weight, and initiated a postural response with occasional steps at 5% body weight. For perturbations at 15 and 17.5% body weight, the dynamic responses of the subject exhibited very similar component time periods when compared with able-bodied subjects undergoing similar postural perturbations. Additionally, the reactive step occurred faster for stronger perturbations than for weaker ones (p < .005, unequal varience t-test.) CONCLUSIONS: This research marks progress towards a controller which can improve the safety and independence of persons with spinal cord injury using implanted neuroprostheses for standing. [ABSTRACT FROM AUTHOR]

Background:The purpose of this review paper is to draw together the large body of literature on steady-state balance and the changes that occur as age increases to enable clinicians to access and interpret this literature and to integrate the findings into their daily practice. Objectives:As there is increasing use of force plate technology in the clinical setting for both assessment and treatment of steady-state stance in people with balance problems, clinicians need a clear understanding of not only the relationship between centre of gravity and base of support (BOS) but also the impact of age and different test conditions. Major findings:This review presents basic balance concepts relating to both the sway characteristics and location of the centre of gravity within BOS and the changes that occur as age increases. The impact of changes in the BOS, such as size and compliance, are also addressed in the context of the ageing client. It is possible that the location of COG within BOS in conjunction with sway characteristics may be more critical in older age groups than in the young as all body systems (sensory, central and musculoskeletal) show declines with increasing age. Conclusions:This paper will assist clinicians to understand characteristics of sway in quiet stance and changes associated with altered test conditions with particular reference to the effects of ageing. [ABSTRACT FROM AUTHOR]

Human beings stand upright with the chain of balance beginning at the feet, progressing to the lower limbs (ankles, knees, hip joints, pelvis), each of the spinal segments, and then ending at the cranium to achieve horizontal gaze and balance using minimum muscle activity. The details of the alignment and balance of the chain, however, are not clearly understood, due to the lack of information regarding the three-dimensional (3D) orientation of all bony elements in relation to the gravity line ( GL). We performed a clinical study to clarify the standing sagittal alignment of whole axial skeletons in reference to the GL using the EOS slot-scanning 3D X-ray imaging system with simultaneous force plate measurement in a healthy human population. The GL was defined as a vertical line drawn through the centre of vertical pressure measured by the force plate. The present study yielded a complete set of physiological alignment measurements of the standing axial skeleton from the database of 136 healthy subjects (a mean age of 39.7 years, 20-69 years; men: 40, women: 96). The mean offset of centre of the acoustic meati from the GL was 0.0 cm. The offset of the cervical and thoracic vertebrae was posterior to the GL with the apex of thoracic kyphosis at T7, 5.0 cm posterior to the GL. The sagittal alignment changed to lordosis at the level of L2. The apex of the lumbar lordosis was L4, 0.6 cm anterior to the GL, and the centre of the base of the sacrum ( CBS) was just posterior to the GL. The hip axis (HA) was 1.4 cm anterior to the GL. The knee joint was 2.4 cm posterior and the ankle joint was 4.8 cm posterior to the GL. L4-, L5- and the CBS-offset in subjects in the age decades of 40s, 50s and 60s were significantly posterior to those of subjects in their 20s. The L5- and CBS-offset in subjects in their 50s and 60s were also significantly posterior to those in subjects in their 30s. HA was never posterior to the GL. In the global alignment, there was a positive correlation between offset of C7 vertebra from the sagittal vertical axis (a vertical line drawn through the posterior superior corner of the sacrum in the sagittal plane) and age, but no correlation was detected between the centre of the acoustic meati- GL offset and age. Cervical lordosis ( CL), pelvic tilt ( PT), pelvic incidence, hip extension, knee flexion and ankle dorsiflexion increased significantly with age. Our results revealed that aging induces trunk stooping, but the global alignment is compensated for by an increase in the CL, PT and knee flexion, with the main function of CL and PT to maintain a horizontal gaze in a healthy population. [ABSTRACT FROM AUTHOR]

Key points We tested perceived head-on-feet orientation and the direction of vestibular-evoked balance responses in passively and actively held head-turned postures., The direction of vestibular-evoked balance responses was not aligned with perceived head-on-feet orientation while maintaining prolonged passively held head-turned postures. Furthermore, static visual cues of head-on-feet orientation did not update the estimate of head posture for the balance controller., A prolonged actively held head-turned posture did not elicit a rotation in the direction of the vestibular-evoked balance response despite a significant rotation in perceived angular head posture., It is proposed that conscious perception of head posture and the transformation of vestibular signals for standing balance relying on this head posture are not dependent on the same internal representation. Rather, the balance system may operate under its own sensorimotor principles, which are partly independent from perception., Abstract Vestibular signals used for balance control must be integrated with other sensorimotor cues to allow transformation of descending signals according to an internal representation of body configuration. We explored two alternative models of sensorimotor integration that propose (1) a single internal representation of head-on-feet orientation is responsible for perceived postural orientation and standing balance or (2) conscious perception and balance control are driven by separate internal representations. During three experiments, participants stood quietly while passively or actively maintaining a prolonged head-turned posture (>10 min). Throughout the trials, participants intermittently reported their perceived head angular position, and subsequently electrical vestibular stimuli were delivered to elicit whole-body balance responses. Visual recalibration of head-on-feet posture was used to determine whether static visual cues are used to update the internal representation of body configuration for perceived orientation and standing balance. All three experiments involved situations in which the vestibular-evoked balance response was not orthogonal to perceived head-on-feet orientation, regardless of the visual information provided. For prolonged head-turned postures, balance responses consistent with actual head-on-feet posture occurred only during the active condition. Our results indicate that conscious perception of head-on-feet posture and vestibular control of balance do not rely on the same internal representation, but instead treat sensorimotor cues in parallel and may arrive at different conclusions regarding head-on-feet posture. The balance system appears to bypass static visual cues of postural orientation and mainly use other sensorimotor signals of head-on-feet position to transform vestibular signals of head motion, a mechanism appropriate for most daily activities. [ABSTRACT FROM AUTHOR]

The present study investigated the effect of haptic input via light touch on standing balance of individuals with incomplete spinal cord injury (iSCI). Centre of pressure (COP) measures during standing were assessed in 16 participants with iSCI (13 males; 61.1 ± 19.9 years; C1-L4; AIS C and D) and 13 able-bodied (AB) participants (10 males; 59.4 ± 19.7 years). The effects of light touch (touch/no touch), vision (eyes open/closed), and group (iSCI/AB) on COP measures were assessed using a two-way mixed design MANOVA. Correlations were examined between changes in COP measures with touch (ΔCOP), and clinical measures of cutaneous pressure and proprioception in the upper (UE) and lower (LE) extremities in participants with iSCI. Significant main effects for touch ( p < 0.001), vision ( p < 0.001), and group ( p = 0.01) for all COP measures were found. There was a significant interaction between vision and group ( p = 0.01) for a subset of COP measures. With eyes closed, ΔCOP was positively correlated with UE cutaneous pressure sensation and negatively correlated with LE proprioception. Compared with AB adults, individuals with iSCI show a greater increase in postural sway when standing with eyes closed than with eyes open. Individuals with iSCI can use light touch to reduce postural sway, and the effect is greater in those with more intact UE cutaneous pressure sensation and more impaired LE proprioception. [ABSTRACT FROM AUTHOR]

Objective: Little is known about how static standing balance changes post total knee arthroplasty (TKA). The primary aim of this study was to examine the sensitivity to change and redundancy of center of pressure (COP) variables post-TKA. The secondary aim was to compare the sensitivity of these measures to standard clinical assessments of one repetition maximum knee extension strength and fast pace gait speed.Design: 466 participants performed instrumented double-limb standing balance tests with eyes open at 4 and 12 weeks post-TKA. Measures of COP standard deviation, amplitude, root mean square (RMS), path length, detrended fluctuation analysis (DFA) and signal frequency content for the medial-lateral (ML) and anterior-posterior (AP) axes were examined.Results: Significant decreases in total path length, ML variables related to sway velocity and AP signal complexity and frequency were observed. Inter-session Cohen's d effect size (ES) revealed the strongest effect was for high velocity ML path length, with a 12% decrease in this rapid sway. This variable, along with AP mean instantaneous frequency and AP DFA, were the only ones significantly different with effect sizes >0.20 and non-redundant (Spearman's rho <0.75). The ES of COP-derived variables (maximum = 0.45) were lower than gait speed (1.40) and knee extensor strength (1.54).Conclusion: Increased high velocity ML sway is present at four compared to 12 weeks post-TKA. This augmented rapid sway may provide increased challenges to the postural control system at a time coinciding with reduced strength levels, which could have implications for physical function during activities of daily living. [ABSTRACT FROM AUTHOR]

Background: The anti-saccadic (AS) error-rate is used to diagnose neurological disorders. The natural aging process could generate difficulty in carrying out parallel neural processes of conscious motor inhibition and eye movement. Therefore, if balance control is imposed on an elderly person in biped positions during an AS movement, an increase in the AS error-rate is expected., Objective: To study the effects of postural control on the AS error-rate in older people., Methods: An intra and intergroup comparison was made of AS error-rate in an experimental group of older people (PM) and another control group of young people (PJ). For this, blocks of AS and pro-saccadic movements (control) were used randomly in four different postures: (1)sitting (SENT), (2)standing normally (NORMAL), (3)feet together (REDUC), and (4)feet in line (TANDEM)., Results: The PM group, compared to the PJ group, showed a progressive increase in the AS error-rate from the sitting position to all standing positions, with the maximum AS error-rate in more complex vertical postures. In contrast, the PJ group did not present significative variability of this AS error-rate in all positions., Conclusions: It is confirmed that the aging process is associated with an increase in the AS error-rate. This study reveals for the first time a significant increase in the AS error-rate when control of body balance is required for PM, implying a decrease in the multiple processing capacity in PM for the execution of complex and parallel tasks., (Copyright © 2023 SEGG. Publicado por Elsevier España, S.L.U. All rights reserved.)