Postural sway in normal subjects aged 20-70 years

Sex-Related Differences in Shoulder Complex Joint Dynamics Variability During Pediatric Manual Wheelchair Propulsion

More than 80% of adult manual wheelchair users with spinal cord injuries will experience shoulder pain. Females and those with decreased shoulder dynamics variability are more likely to experience pain in adulthood. Sex-related differences in shoulder dynamics variability during pediatric manual wheelchair propulsion may influence the lifetime risk of pain. We evaluated the influence of sex on 3-dimensional shoulder complex joint dynamics variability in 25 (12 females and 13 males) pediatric manual wheelchair users with spinal cord injury. Within-subject variability was quantified using the coefficient of variation. Permutation tests evaluated sex-related differences in variability using an adjusted critical alpha of P = .001. No sex-related differences in sternoclavicular or acromioclavicular joint kinematics or glenohumeral joint dynamics variability were observed (all P ≥ .042). Variability in motion, forces, and moments are considered important components of healthy joint function, as reduced variability may increase the likelihood of repetitive strain injury and pain. While further work is needed to generalize our results to other manual wheelchair user populations across the life span, our findings suggest that sex does not influence joint dynamics variability in pediatric manual wheelchair users with spinal cord injury.

Differing postural control patterns in individuals with bilateral and unilateral hearing loss

OBJECTIVES

Hearing loss (HL) is associated with imbalance and increased fall risk. The mechanism underlying this relationship and differences across types of hearing loss remains unclear. Head mounted displays (HMD) can shed light on postural control mechanisms via an analysis of head sway.

PURPOSE

The purpose of this study was to evaluate head sway in response to sensory perturbations in individuals with bilateral (BHL) or unilateral hearing loss (UHL) and compare them to controls.

MATERIALS AND METHODS

We recruited 36 controls, 23 individuals with UHL and 14 with BHL. An HMD (HTC Vive) measured head sway while participants stood on the floor, hips-width apart. Stimuli included two levels of visuals and sound. Root Mean Square Velocity (RMSV) and Power Spectral Density (PSD) were used to quantify head sway.

RESULTS

Adjusting for age, individuals with BHL had significantly higher anterior-posterior and medio-lateral RMSV than controls and individuals with UHL. Individuals with UHL demonstrated significantly lower response to visual perturbations in RMSV AP and in all 3 frequency segments of PSD compared to controls. Individuals with UHL showed significantly lower movements at high frequencies compared to controls. Sounds or severity of HL did not impact head sway.

CONCLUSIONS

Individuals with BHL demonstrated increased sway with visual perturbations and should be clinically assessed for balance performance and fall risk. Individuals with UHL exhibited reduced responses to visual stimuli compared with controls, which may reflect conscious movement processing. Additional studies are needed to further understand the mechanistic relationship between hearing loss and imbalance.

Test-Retest reliability and preliminary reliable change estimates for Sway Balance tests administered remotely in community-dwelling adults

OBJECTIVE

Impaired balance and postural stability can occur with advanced age, following traumatic brain injury, in association with neurological disorders and diseases, and as the result of acute or chronic orthopedic problems. The remote assessment of balance and postural stability could be of value in clinical practice and research. We examined the test-retest reliability and reliable change estimates for Sway Balance Mobile Application tests (Sway Medical, Tulsa OK, USA) administered remotely from the participant's home.

METHOD

Primarily young, healthy community-dwelling adults completed Sway Balance Mobile Application tests remotely on their personal mobile devices once per week for three consecutive weeks while being supervised with a video-based virtual connection. Sway Balance tests include five stances (i.e., feet together, tandem right foot forward, tandem left foot forward, single leg right foot, single leg left foot), which are averaged to compute a Sway Balance composite score from 0 to 100, with higher scores indicating better postural stability. We examined test-retest reliability (measured with intraclass correlation coefficients, ICCs) and preliminary reliable change estimates for 70%, 80%, and 90% confidence intervals.

RESULTS

Participants included 55 healthy adults (ages = 26.7 ± 9.9 years, interquartile range = 20-30, range = 18-58; 38 [69%] women). Test-retest reliability for the Sway Balance composite score across three weeks was.88. Test-retest reliability for individual stances ranged from 62 to 83 (all ps < 0.001). At the 80% confidence interval, preliminary reliable changes estimates were 9 points for the Sway Balance composite score.

CONCLUSIONS

For a remote administration, test-retest reliability was moderate-to-good for all Sway Balance stances, as well as for the Sway Balance composite score. Reliable change estimates may allow clinicians to determine whether an improvement or decline in performance is greater than the expected improvement or decline due to measurement error in young adults.

Sensory system-specific associations between brain structure and balance

Nearly 75% of older adults in the US report balance problems. Although it is known that aging results in widespread brain atrophy, less is known about how brain structure relates to balance in aging. We collected T1- and diffusion-weighted MRI scans and measured postural sway of 36 young (18-34 years) and 22 older (66-84 years) adults during eyes open, eyes closed, eyes open-foam, and eyes closed-foam conditions. We calculated summary measures indicating visual, proprioceptive, and vestibular contributions to balance. Across both age groups, thinner cortex in multisensory integration regions was associated with greater reliance on visual inputs for balance. Greater gyrification within sensorimotor and parietal cortices was associated with greater reliance on proprioceptive inputs. Poorer vestibular function was correlated with thinner vestibular cortex, greater gyrification within sensorimotor, parietal, and frontal cortices, and lower free water-corrected axial diffusivity across the corona radiata and corpus callosum. These results expand scientific understanding of how individual differences in brain structure relate to balance and have implications for developing brain stimulation interventions to improve balance.

Postural Balance and Gait Parameters of Independent Older Adults: A Sex Difference Analysis

Postural balance and gait are important factors in the functional status of older people; however, few studies have addressed differences by sex. The objective of this study was to analyze the postural balance and temporal−spatial parameters of gait in independent older adults by sex. A cross-sectional study was conducted. Thirty-eight independent older women (69 ± 5 years), and 33 men (71 ± 5 years) were evaluated. The postural balance test with open and closed eyes was performed on two surfaces (hard/soft) on a force platform. Gait was recorded with cameras to analyze cycle duration and speed, step length, stride length, and foot clearance. The area of postural balance was greater in men in all tests (p < 0.001). Foot clearance height and cycle duration were lower in women (p < 0.05). Men showed a negative correlation between the area of balance and gait parameters. In women, a positive correlation was observed between foot clearance and balance with eyes closed. The postural balance and gait suggest discrepancies by sex, showing that older men behave differently according to the requirement of the motor task compared to women. These findings suggest being corroborated in more complex studies in the future.

Effects of age, sex and task on postural sway during quiet stance

BACKGROUND

Postural sway during quiet standing has been shown as a useful task to assess risk of falling in older adults. While the risk of falling is consistently reported to be higher in older females than males, the sex-related differences in postural sway are not consistent across the studies.

RESEARCH QUESTION

What are the effects of age and sex on postural sway during quiet standing during different stance conditions?

METHODS

We examined the effects of age (40 young and 34 older adults), sex (37 males and 37 females), and their interaction on the postural sway during different stance conditions. We compared the center of pressure (CoP) velocity, amplitude and frequency during parallel (eyes open and eyes closed) and semi-tandem (eyes open) stances.

RESULTS

Our results suggest that postural sway is similar between sexes in young participants, while older males exhibit larger postural sway than older female participants (10/21 outcomes). Older female participants exhibited lower CoP amplitude (but larger total and anterior-posterior CoP velocity) compared to young female participants. We also found that the increase in the postural sway with increasing task difficulty is more pronounced in older vs. young adults.

SIGNIFICANCE

This study shows that ageing-related changes in postural sway are sex- and task-specific. Researchers and clinicians need to be aware of these effects when comparing groups or monitoring changes in time.

Bariatric surgery and exercise: A pilot study on postural stability in obese individuals

This study aimed to analyze the changes in postural stability of individuals with obesity after bariatric surgery, and the effect of three months of regular exercise on the static postural stability. Twenty-two subjects (7 females and 15 males) aged 31 to 68 years (Body mass index 35-55 kg.m-2) completed the study. Participants were divided into two groups: one group participated in an exercise program after the bariatric surgery (n = 10; age 48.9 ± 7.5 years; Body mass index 42 ± 5.6 kg.m-2) while the second group did not exercise at all after bariatric surgery (n = 12; age 44.7 ± 13.6 years, Body mass index 42.6 ± 6.0 kg.m-2). Static postural stability was measured using a Tekscan MobileMat pressure plate before and 4 months after the bariatric surgery. The exercise program included exercising three times a week including: one hour of strengthening, one hour of aerobic group exercise and at least one session of individual exercise at home. There were no significant differences in Center of force sway, Center of force ranges and average speed before and 4 months after bariatric surgery. Also, no effect of exercise was found. Post-pre differences of some parameters were negatively related to age (r from-0.46 to-0.72). Further studies are needed to explore this topic in depth.

The effect of age, sex and a firm-textured surface on postural control

In previous studies, the influence of plantar sensation has been examined using various textured surfaces with different stiffness materials to assess static balance. This study investigated the effects of a Firm Textured Surface (FTS) along with age and sex-related influences on postural control under different visual conditions. Forty subjects (20 elderly, 10 males, mean age 68.30, 10 females, mean age 68.00, and 20 young people, 10 males, mean age 25.45, 10 females, mean age 27.30) participated in this study maintained a quiet standing on FTS, foam and firm surfaces with eyes open and closed. The center of pressure displacement (CoP_DISP), CoP velocity (CoP_VEL), and sway velocity of the CoP in anteroposterior (AP) and mediolateral (ML) direction (V_A/P and V_M/L) were measured. FTS was associated with lower postural sway measures in both the groups with eyes open and closed. However, the foam surface showed the worst results in all postural parameters under all experimental conditions. Separate four-way ANOVAs were applied to each dependent variable. The main effects of surface (p < 0.0001), vision (p < 0.0001) and age (p < 0.0001 for CoP_DISP, CoP_VEL and V_A/P; p = 0.0003 for V_M/L) were significant in each of the four fitted models. Sex was never significant, either as a main effect or an interaction with other experimental factors. Eyes open were able to reduce the negative effects of the foam surfaces but without vision the proprioceptive sensory system cues of the body state become more important for maintaining balance. A good stimulation with rigid texture should be considered as relief to reduce the physiological-related decline of afferent information with age.

Differences in the Effect of Sleep Deprivation on the Postural Stability among Men and Women

Objective: Sleepiness caused by sleep deprivation may increase the risk of injuries and damages during physical activity. Individual data so far indicate a generally better static postural stability of women regardless of sleeping conditions. The main aim of this study was to assess the impact of sleep deprivation on postural stability according to gender after 24 h of sleep deprivation. Methods: Participants included 83 students (36 men and 47 women). Postural stability was measured with eyes open and closed eyes before and after sleep deprivation. Data from posturographic platform were used to assess postural stability objectively. Results: The type of test determined the size of observed changes in postural stability. The data suggest that women are better able to cope with the effects of sleep deprivation than men. Conclusion: Postural control system is very important in sport and in physically active people. The results show that men are more sensitive to sleep deprivation than women because they had higher COP (center of pressure) values in tests. Less postural stability of the body due to sleep deprivation indicates a higher risk of injury during physical activity.

Concurrent and discriminant validity of Nintendo Wii Fit exergame for the assessment of postural sway

[Purpose] The purpose of this study was to determine the concurrent validity of Wii Fit center-of-pressure parameters with Clinical Test of Sensory Integration for Balance and to evaluate the discriminant validity of the Wii Fit center-of-pressure parameters for adults and the elderly for the assessment of postural sway. [Participants and Methods] This study used an observational cross-sectional correlational design. All 70 participants were required to complete a questionnaire for eligibility screening, followed by a center-of-pressure assessment using three Wii Fit balance activities (snowboard slalom, ski slalom, and balance bubble) and Clinical Test of Sensory Integration for Balance using a force platform. [Results] For center-of-pressure assessment, our results showed there was concurrent validity of Wii Fit ski slalom and balance bubble with Clinical Test of Sensory Integration for Balance conditions 6 and 4, respectively. Our results also demonstrated that the three Wii Fit balance activities selected in this study could be used to discriminate between adults and the elderly. [Conclusion] Our results suggest that Wii Fit is a viable and affordable alternative method for center-of-pressure assessment.

Which features of postural sway are effective in distinguishing Parkinson's disease from controls? A systematic review

BACKGROUND

Postural sway may be useful as an objective measure of Parkinson's disease (PD). Existing studies have analyzed many different features of sway using different experimental paradigms. We aimed to determine what features have been used to measure sway and then to assess which feature(s) best differentiate PD patients from controls. We also aimed to determine whether any refinements might improve discriminative power and so assist in standardizing experimental conditions and analysis of data.

METHODS

In this systematic review of the literature, effect size (ES) was calculated for every feature reported by each article and then collapsed across articles where appropriate. The influence of clinical medication status, visual state, and sampling rate on ES was also assessed.

RESULTS

Four hundred and forty-three papers were retrieved. 25 contained enough information for further analysis. The most commonly used features were not the most effective (e.g., PathLength, used 14 times, had ES of 0.47, while TotalEnergy, used only once, had ES of 1.78). Increased sampling rate was associated with increased ES (PathLength ES increased to 1.12 at 100 Hz from 0.40 at 10 Hz). Measurement during "OFF" clinical status was associated with increased ES (PathLength ES was 0.83 OFF compared to 0.21 ON).

CONCLUSIONS

This review identified promising features for analysis of postural sway in PD, recommending a sampling rate of 100 Hz and studying patients when OFF to maximize ES. ES complements statistical significance as it is clinically relevant and is easily compared across experiments. We suggest that machine learning is a promising tool for the future analysis of postural sway in PD.

Standard reference values of weight and maximum pressure distribution in healthy adults aged 18-65 years in Germany

Background

The aim of this study was to collect standard reference values of the weight and the maximum pressure distribution in healthy adults aged 18–65 years and to investigate the influence of constitutional parameters on it.

Methods

A total of 416 healthy subjects (208 male / 208 female) aged between 18 and 65 years (Ø 38.3 ± 14.1 years) participated in this study, conducted 2015–2019 in Heidelberg. The age-specific evaluation is based on 4 age groups (G1, 18–30 years; G2, 31–40 years; G3, 41–50 years; G4, 51–65 years). A pressure measuring plate FDM-S (Zebris/Isny/Germany) was used to collect body weight distribution and maximum pressure distribution of the right and left foot and left and right forefoot/rearfoot, respectively.

Results

Body weight distribution of the left (50.07%) and right (50.12%) foot was balanced. There was higher load on the rearfoot (left 54.14%; right 55.09%) than on the forefoot (left 45.49%; right 44.26%). The pressure in the rearfoot was higher than in the forefoot (rearfoot left 9.60 N/cm², rearfoot right 9.51 N/cm²/forefoot left 8.23 N/cm², forefoot right 8.59 N/cm²). With increasing age, the load in the left foot shifted from the rearfoot to the forefoot as well as the maximum pressure (p ≤ 0.02 and 0.03; poor effect size). With increasing BMI, the body weight shifted to the left and right rearfoot (p ≤ 0.001, poor effect size). As BMI increased, so did the maximum pressure in all areas (p ≤ 0.001 and 0.03, weak to moderate effect size). There were significant differences in weight and maximum pressure distribution in the forefoot and rearfoot in the different age groups, especially between younger (18–40 years) and older (41–65 years) subjects.

Discussion

Healthy individuals aged from 18 to 65 years were found to have a balanced weight distribution in an aspect ratio, with a 20% greater load of the rearfoot. Age and BMI were found to be influencing factors of the weight and maximum pressure distribution, especially between younger and elder subjects. The collected standard reference values allow comparisons with other studies and can serve as a guideline in clinical practice and scientific studies.

Effect of head roll-tilt on the subjective visual vertical in healthy participants: Towards better clinical measurement of gravity perception

OBJECTIVE

Gravity perception is an essential function for spatial orientation and postural stability; however, its assessment is not easy. We evaluated the head-tilt perception gain (HTPG, that is, mean perceptual gain [perceived/actual tilt angle] during left or right head roll-tilt conditions) and head-upright subjective visual vertical (SVV) using a simple method developed by us to investigate the characteristics of gravity perception in healthy participants.

METHODS

We measured the SVV and head roll-tilt angle during head roll-tilt within ±30° of vertical in the sitting and standing positions while the participant maintained an upright trunk (sitting, 434 participants; standing, 263 participants). We evaluated the head-upright SVV, HTPG, and laterality of the HTPG.

RESULTS

We determined the reference ranges of the absolute head-upright SVV (<2.5°), HTPG (0.80-1.25), and HTPG laterality (<10%) for the sitting position. The head-upright SVV and HTPG laterality were not influenced by sex or age. However, the HTPG was significantly greater in women than in men and in middle-aged (30-64 years) and elderly (65-88 years) participants than in young participants (18-29 years). The HTPG, but not the head-upright SVV or HTPG laterality, was significantly higher in the standing vs sitting position.

CONCLUSION

The HTPG is a novel parameter of gravity perception involving functions of the peripheral otolith and neck somatosensory systems to the central nervous system. The HTPG in healthy participants is influenced by age and sex in the sitting position and immediately increases after standing to reinforce the righting reflex for unstable posture, which was not seen in the head-upright SVV, previously considered the only parameter.

LEVEL OF EVIDENCE

4.

Comparison of Postural Sway, Plantar Cutaneous Sensation According to Saccadic Eye Movement Frequency in Young Adults

The crossover trial study aimed to identify the saccadic eye movement (SEM) frequency to improve postural sway (PS) and plantar cutaneous sensation (PUS) in young adults. The 17 participants randomly performed 0.5-, 2-, and 3-Hz SEM. The SEM frequency was determined to allow the target to appear once per 2 s (0.5 Hz), twice per second (2 Hz), or thrice per second (3 Hz). SEM performance time was 3 min with a washout period of 5 min. PS and PUS were measured at baseline and during 0.5-Hz, 2-Hz, and 3-Hz SEMs using a Zebris FDM 1.5 force plate. PS was determined by measuring the sway area, path length, and speed of center of pressure (COP) displacement, and PUS was determined via the plantar surface area (PSA). In PS parameters, there was a significant difference among the SEM frequencies in the COP_{sway area} PSA_{left foot} and PSA_{right foot}. Compared to that at baseline, COP_{sway area} decreased at 0.5 Hz and 2 Hz, while PSA_{left foot} and PSA_{right foot} increased at 2 Hz. These results suggest that 2 Hz SEM may improve PS and PSA.

The Postural Stability Measures Most Related to Aging, Physical Performance, and Cognitive Function in Healthy Adults

Background

Different measures have been used to quantify body balance; some of which use technology to measure postural sway, others are physical performance or self-reported. However, there is little information on the best postural sway measures associated with aging, physical performance, and cognitive function measures.

Objective

To evaluate the relationship between postural sway measures and aging, physical performance, and cognitive function measures.

Methods

A total of 51 subjects (53% female, mean age 53.2 ± 21 years) participated in this cross-sectional study. The participants completed the Activities-specific Balance Confidence (ABC) Scale questionnaire, the Functional Gait Assessment (FGA), the Montreal Cognitive Assessment (MoCA) test, and gait speed. Afterward, the participants performed 8 balance exercises, and their postural sway was measured using a force plate. Spearman's rank correlation coefficient was used to examine the relationship between the study variables.

Results

Age was negatively associated with cognitive function, gait speed, ABC scores, and FGA scores. In addition, cognitive ability was associated positively with ABC scores (r = 0.38, p ≤ 0.01). Age, FGA scores, and gait speed were significantly associated with the postural sway of the AP direction in some exercises and in all exercises in the ML directions (p < 0.05). The cognitive function and ABC scores were significantly associated with only postural sway measures in the ML direction (p < 0.05).

Conclusion

The postural sway measures in the lateral direction had more and stronger associations with age, physical performance, and cognitive function measures compared to those in the AP direction.

Locomotive syndrome and the power spectral characteristics of body sway

AIM

In Japan, nursing care is advised for patients with locomotive syndrome (LS) because of musculoskeletal disorders. Balance tests have indicated an association between LS risk and sway size related to center of pressure (COP) movement. Here, the power spectrum represents the energy contained in each frequency of COP sway. Although balance tests are often performed during health checkups, no studies have investigated the relationship between the power spectrum and LS. This study investigated this relationship.

METHODS

In total, 605 recipients of health checkups were evaluated for LS using the 25-item Geriatric Locomotive Function Scale. Power spectrums were calculated by applying fast Fourier transform to COP sway time-series data. These were classified into three sections (0.02-0.2 Hz [low-frequency band; LFB], 0.2-2 Hz [mid-frequency band], and 2-10 Hz [high-frequency band; HFB]). Power spectrums were evaluated in left-right and front-back directions.

RESULTS

LS was associated with significantly lower ratios for both the HFB (P = 0.001) in the left-right direction and LFB (P = 0.007) in the front-back direction. In addition, men had significantly lower HFB ratios in the left-right direction (P = 0.032) and LFB ratios in the front-back (P = 0.013), whereas women had significantly lower HFB ratios in the left-right direction (P = 0.007).

CONCLUSIONS

LS was associated with significantly lower ratios for both the HFB in the left-right direction and LFB in the front-back direction. This understanding of the power spectral characteristics of LS may be useful in the context of pathology and therapeutic intervention. Geriatr Gerontol Int ••; ••: ••-•• Geriatr Gerontol Int 2020; ••: ••-••.

Differences in postural sway among healthy adults are associated with the ability to perform steady contractions with leg muscles

Upright standing involves small displacements of the center of mass about the base of support. These displacements are often quantified by measuring various kinematic features of the center-of-pressure trajectory. The plantar flexors have often been identified as the key muscles for the control of these displacements; however, studies have suggested that the hip abductor and adductors may also be important. The purpose of our study was to determine the association between the force capabilities of selected leg muscles and sway-area rate across four balance conditions in young (25 ± 4 years; 12/19 women) and older adults (71 ± 5 years; 5/19 women). Due to the marked overlap in sway-area rate between the two age groups, the data were collapsed, and individuals were assigned to groups of low- and high-sway area rates based on a k-medoid cluster analysis. The number of participants assigned to each group varied across balance conditions and a subset of older adults was always included in the low-sway group for each balance condition. The most consistent explanatory variable for the variance in sway-area rate was force control of the hip abductors and ankle dorsiflexors as indicated by the magnitude of the normalized force fluctuations (force steadiness) during a submaximal isometric contraction. The explanatory power of the regression models varied across conditions, thereby identifying specific balance conditions that should be examined further in future studies of postural control.

Postural control in healthy adults: Determinants of trunk sway assessed with a chest-worn accelerometer in 12 quiet standing tasks

Many diseases and conditions decrease the ability to control balance. In clinical settings, there is therefore a major interest in the assessment of postural control. Trunk accelerometry is an easy, low-cost method used for balance testing and constitutes an alternative method to the posturography using force platforms. The objective was to assess the responsiveness of accelerometry in a battery of 12 quiet standing tasks. We evaluated the balance of 100 healthy adults with an accelerometer fixed onto the sternum. We used the average amplitude of acceleration as an indirect measure of postural sways. The tasks of increased difficulty were realized with or without vision. The battery of tasks was repeated four times on two different days to assess reliability. We analyzed the extent to which the task difficulty and the absence of vision affected the trunk sway. The influence of individual characteristics (age, height, mass, sex, and physical activity level) was also assessed. The reliability analysis revealed that four repetitions of the battery of tasks are needed to reach a high accuracy level (mean ICC = 0.85). The results showed that task difficulty had a very large effect on trunk sways and that the removal of vision further increased sways. Concerning the effects of individual characteristics, we observed that women tended to oscillate more than men did in tasks of low difficulty. Age and physical activity level also had significant effects, whereas height and mass did not. In conclusion, age, sex, and physical fitness are confounders that should be considered when assessing patients’ balance. A battery of simple postural tasks measured by upper-trunk accelerometry can be a useful method for simple balance evaluation in clinical settings.

Inter-gender differences of balance indicators in persons 60-90 years of age

Introduction

Precision of movements responsible for maintaining balance deteriorates with age due to natural involutionary processes, thus prompting a research question whether the values of gender-related stability indicators might differ significantly among the study subjects over 60 years of age.

Methods

The study group comprised 136 seniors (89 women, 47 men; aged 60–90 years). The CQ-Stab 2P 2-platform posturograph was used as the main research device, whereas the Mann–Whitney U-test was used to evaluate the gender-related differences in the average level of variables.

Results

In the open-eye test, significant gender-related differences were observed with regard to the statokinesiogram’s path length in the mediolateral (ML) direction in the subjects aged 60–69 years (p=0.004), mean frequency of center of pressure (COP) displacement and number of COP displacements in the ML direction in the subjects aged 70–79 years (p=0.028, p=0.019), and mean COP displacement in the anteroposterior (AP) direction in the subjects aged 80–90 years (p=0.026). When the subjects were deprived of visual control, gender-related differences were observed with regard to the mean frequency of COP displacement, number of COP displacements in the ML direction in the subjects aged 60–69 years (p=0.045, p=0.049), and the statokinesiogram’s path length in the AP direction in the subjects aged 70–79 years (p=0.015). In the oldest age group, the differences were noted in the statokinesiogram’s path length in the AP direction (p=0.001), a sway area delimited by the COP point (p=0.003), range of AP stability (p<0.001), and range of ML stability (p=0.048).

Conclusion

Gender-related differences affecting postural stability were found in the elderly. Men were characterized by a lower level of postural stability when compared with women. This highlights the need to have the gender-related differences taken into account, when developing various preventive and therapeutic programs specifically aimed at compensating certain involution-dependent deficits.

Postural sway, working years and BMI in healthy truck drivers: an observational study

OBJECTIVES

The following study analyses the influence of risk factors among the occupational group of truck drivers on postural control and body mass index (BMI).

DESIGN

Observational study.

SETTING

One motorway station close to several highways in Germany.

PARTICIPANTS

180 truck drivers (177 male/3 female), aged 21-65 years old, took part in this study.

OUTCOME MEASURES

Postural control was examined using a pressure plate. In order to examine the influence of body weight (BMI) and working years on postural control, subjects were divided into samples of five and three groups, respectively. Furthermore, it was evaluated whether the subjects suffered from back pain. For data analysis, the Kruskal-Wallis test was used as the data were not normally distributed. Once the p value of the Kruskal-Wallis test was p≤0.05, the Conover-Iman comparison and afterwards the Bonferroni-Holm correction were used. The significance level was set at α ≤0.05.

RESULTS

Regarding the number of working years, a significant increase of frontal (p≤0.04) and sagittal (p≤0.001) sway were observed. The correlation of the five BMI groups with the number of working years demonstrates that an increase of the working years leads to an increase of BMI (p≤0.03). Furthermore, the majority of truck drivers participating in this study suffered from back pain (61.7%).

CONCLUSIONS

BMI and musculoskeletal impairment are indicators of health risk factors. In this study, it is shown that an increasing number of working years and an increasing BMI lead to a decrease in frontal and sagittal postural sway. In addition, the number of working years correlates with body weight and back pain.

Spinal and corticospinal pathways are differently modulated when standing at the bottom and the top of a three-step staircase in young and older adults

PURPOSE

This study investigated the modulation of spinal (group Ia afferents) and corticospinal pathways when young (22.7 ± 1.3 years) and older adults (72.2 ± 7.9 years) stood at the bottom and at the top of a three-step staircase equipped with force platforms.

METHOD

Changes in submaximal H-reflex amplitude (H ₅₀) and slope of the H-reflex input-output relation (spinal pathway), and in amplitude of motor-evoked potentials (MEP) triggered by transcranial magnetic stimulation (corticospinal pathway) at two intensities (1.1× and 1.2× motor threshold) were recorded in soleus when subjects stood as steady as possible downstairs and upstairs. The centre of pressure (CoP) excursion was analyzed in the time and frequency domains in both conditions.

RESULTS

Regardless of age, the mean CoP velocity was greater when standing upstairs (11.1 ± 3.5 mm s^-1) than downstairs (9.0 ± 2.3 mm s^-1; p = 0.002). The CoP power spectral density (PSD) in the 0-0.5 Hz band was greater upstairs than downstairs (+18.4%; p = 0.03) whereas PSD in the 2-20Hz frequency band was lesser (-41%) upstairs than downstairs (p < 0.001), regardless of age. In both groups, the H ₅₀ amplitude (-30.6%; p < 0.001) and slope of H-reflex input-output relation (-10.2%; p = 0.002) were lesser when standing upstairs than downstairs, whereas no significant difference was observed in MEP amplitude and silent period between balance conditions (p > 0.05).

CONCLUSION

These results indicate a lower dependence on spinal pathway to control soleus motor neurones when standing upstairs than downstairs accompanied by a change in postural control. This suggests that healthy older adults preserved their ability to adjust postural control to environmental demands.

Characteristics of hand tremor and postural sway in patients with fetal-type Minamata disease

About forty certified patients aged around 50 years old existed as living witnesses to fetal-type Minamata disease (methylmercury poisoning due to in utero exposure) in Minamata, Japan in 2006. Computerized hand tremor and postural sway tests with spectral analysis were conducted for 24 of them and in matched control subjects to examine the pathophysiological feature of neuromotor function. The tremor intensities of the patients with fetal-type Minamata disease were significantly larger than those of the 67 controls at every frequency band for both hands. In the patients, proportions for intensity at 1-6 Hz of both hands were larger, but those of the intensity at 6-10 Hz were smaller compared with the controls. The center frequency of a tremor was significantly lower in the patients than in the controls. Only eight males of the 24 patients were examined to evaluate postural sway because of extremely low scores in activities of daily living in the remaining. Most of the postural sway parameters obtained with eyes open and closed were significantly larger in the patients than in the male controls. Likewise, Romberg quotients of postural sway in anterior-posterior direction were significantly higher in the patients. In conclusion, the patients with fetal-type Minamata disease of our study showed a larger tremor of low frequency at less than 6 Hz and postural instability. Spectral analyses of computerized hand tremor and postural sway are suggested to be useful for assessing the pathophysiological change, related to a lesion of the cerebellum, resulting from prenatal methylmercury exposure.

Core Training and Rehabilitation in Horses

The central body axis or core is a key component in controlling body posture and providing a stable platform for limb movements and generation of locomotor forces. Persistent dysfunction of the deep stabilizing muscles seems to be common in horses indicating a need for core training exercises to restore normal function. Core training should be performed throughout the horse's athletic career to maintain a healthy back and used therapeutically when back pain is identified. This article reviews the structure and function of the equine thoracolumbar spine with special reference to function, dysfunction, conditioning, and rehabilitation of the core musculature.

Quantifying effects of age on balance and gait with inertial sensors in community-dwelling healthy adults

Although balance and gait deteriorate as a person ages, it is unknown if all balance and gait measures change similarly across the adult age span. We developed the Instrumented Stand and Walk test (ISAW) to provide a quick quantification of key components of balance and walking: postural sway, anticipatory postural adjustments during step initiation, gait, and turning using body-worn, inertial sensors. Our aims were to characterize how different balance and gait measures change with age and to identify key age-related measures of mobility, in a wide age range of healthy, community-dwelling adults. A total of 135 healthy, community-dwelling subjects of age range 21-89years with no history of falls were enrolled. Subjects wore inertial sensors on the wrists, ankles, sternum and lumbar area; 37 reliable and valid measures of postural sway, step initiation, gait and turning were computed. Univariate and multivariate regression analyses were performed to examine how the measures changed with age. Several distinct correlation patterns between age and ISAW measures were observed: linear deterioration, deterioration after plateau, and subtle, or no, worsening. Spatial, but not temporal, measures of gait were age-related. The strongest age correlation was found for centroidal frequency of mediolateral postural sway (r=-0.50, p≤0.001). A hierarchical regression model revealed that age was the most important predictor of mediolateral centroidal frequency, with lower sway frequencies associated with older age, independent of gender, weight, and height. Our results showed that balance and gait represent independent control systems for mobility and not all balance and gait measures deteriorate the same way with age. Postural sway during stance was more strongly related to age than any gait, gait initiation or turning measure.

The Association between Different Levels of Alcohol Use and Gait under Single and Dual Task in Community-Dwelling Older Persons Aged 65 to 70 Years

Objectives. This study aimed to describe the cross-sectional and longitudinal association between alcohol intake and gait parameters in older persons. Methods. Community-dwelling persons aged 65–70 years (N = 807). Information on health, functional status, and alcohol use was self-reported at baseline and at 3-year follow-up, whereas gait speed and stride-to-stride variability were measured while walking only (single task) and under dual tasking (counting backwards). Results. Compared to light-to-moderate drinking, heavy drinking was associated with slower gait speed in single task (adj. coeff.: −.040, 95% CI: −.0.78 to −.002, p = .035). No significant association was observed between heavy drinking and gait speed variability. Nondrinkers walked significantly slower than light-to-moderate drinkers in dual task and had significantly higher gait speed variability in both single and dual task, but these associations disappeared after adjustment for comorbidity. At follow-up, 35.2% and 34.1% of the participants walked significantly slower in single and dual task, respectively. This proportion varied a little across drinking categories. Conclusion. At baseline, heavy alcohol consumption was significantly associated with slower gait speed in single task. Selective survival of the fittest heavy drinkers probably explains why this association faded in longitudinal analyses. The trend of poorer gait performance in nondrinkers disappeared after adjustment for comorbidity, suggesting confounding by a worse health status.

Does a mineral wristband affect balance? A randomized, controlled, double-blind study

Background

Having good balance is a facilitating factor in the performance of everyday activities. Good balance is also essential in various sport activities in order to both get results and prevent injury. A common measure of balance is postural sway, which can be measured both antero-posteriorly and medio-laterally. There are several companies marketing wristbands whose intended function is to improve balance, strength and flexibility. Randomized controlled trials have shown that wristbands with holograms have no effect on balance but studies on wristbands with minerals seem to be lacking.

Objective

The aim of this study was to investigate if the mineral wristband had any effect on postural sway in a group of healthy individuals.

Study design

Randomized, controlled, double-blind study.

Material/Methods

The study group consisted of 40 healthy persons. Postural sway was measured antero-posteriorly and medio-laterally on a force plate, to compare: the mineral wristband, a placebo wristband, and without any wristband. The measurements were performed for 30 s, in four situations: with open eyes and closed eyes, standing on a firm surface and on foam. Analyses were made with multilevel technique.

Results

The use of wristband with or without minerals did not alter postural sway. Closed eyes and standing on foam both prolonged the dependent measurement, irrespective if it was medio-lateral or antero-posterior. Wearing any wristband (mineral or placebo) gave a small (0,22-0,36 mm/s) but not statistically significant reduction of postural sway compared to not wearing wristband.

Conclusion

This study showed no effect on postural sway by using the mineral wristband, compared with a placebo wristband or no wristband. Wearing any wristband at all (mineral or placebo) gave a small but not statistically significant reduction in postural sway, probably caused by sensory input.

The D+R Balance application: a novel method of assessing postural sway

Background:

Postural sway can be assessed clinically using the Romberg test, or quantified using dynamic posturography. We assessed the potential use of a novel iPhone application as a method of quantifying sway.

Methods:

Fifty healthy volunteers performed the Romberg and tandem Romberg tests on a hard floor and on foam in soundproofed and normal clinic rooms. Postural sway was recorded using the D+R Balance application and data were compared using pairedt-tests.

Results:

Significantly more postural sway was noted in participants when standing with their eyes closed and feet in the ‘tandem’ positionvsfeet together; standing with their eyes closed on foamvson the floor; and standing with their eyes closed on foam with feet in the tandem positionvson the floor with feet together.

Conclusion:

This feasibility study suggests that the iPhone D+R Balance application deserves further investigation as a means of assessing postural sway and may provide an alternative to current dynamic posturography systems.

The effect of cervical spine manipulation on postural sway in patients with nonspecific neck pain

OBJECTIVE

This crossover study aimed to determine whether a single high-velocity, low-amplitude manipulation of the cervical spine would affect postural sway in adults with nonspecific neck pain.

METHODS

Ten participants received, in random order, 7 days apart, a high-velocity, low-amplitude manipulation applied to a dysfunctional spinal segment and a passive head-movement control. Four parameters of postural sway were measured before, immediately after, and at 5 and 10 minutes after each procedure.

RESULTS

Results showed no differences between interventions in change in any of the parameters. When changes before and immediately after each procedure were analyzed separately, only the control showed a significant change in the length of center of pressure path (an increase from median, 118 mm; interquartlie range, 93-137 mm to an increase to 132 mm; 112-147; P = .02).

CONCLUSION

This study failed to show evidence that single manipulation of the cervical spine influenced postural sway. Given the ability of the postural control system to reweight the hierarchy of sensory information to compensate for inadequacies in any 1 component, it is possible that any improvements in the mechanisms controlling postural sway elicited by the manipulative intervention may have been concealed.

Influence of gender and physical exercise on balance of healthy young adults

Objective To verify the effects of gender and physical activity on postural sway. Method A cross-sectional study was conducted to analyze upright balance of young men and women between the ages of 20-30, both active and sedentary. Study participants were 60 individuals, who were divided into: active women (n = 15), sedentary women (n = 15), active men (n = 15) and sedentary men (n = 15). The International Physical Activity Questionnaire (IPAQ) short form, was used to evaluate each participant’s level of physical activity. According to the questionnaire, active individuals are those who carry out moderate activity, with an energy expenditure between 3.5 and 6 METs (1 MET: 3.5 ml/kg/min), or vigorous activity, with an energy expenditure above 6 METs, at least three days a week for 20 minutes. To assess control of postural sway, we measured the amplitude and velocity of anteroposterior (AP) and mediolateral (ML) sway in standing position, with their eyes open and closed, with and without foam, on a force platform. Results Comparison between genders revealed that, when compared to sedentary women, sedentary men displayed poorer performance in velocity and amplitude of AP postural control sway with their eyes closed, with and without foam. There were no differences in the amplitude and velocity of ML sway, both with open and closed eyes among groups (p < 0.05). There were no differences when comparing physically active men and women either. Conclusion Sedentary men seem to rely more on vision for maintaining postural control in quiet standing situations with respect to women.

Effects of age and gender on dynamic stability during stair descent

OBJECTIVE

To determine the effects of age and sex and their interaction effects on dynamic postural stability during stair descent.

DESIGN

Cross sectional.

SETTING

Laboratory.

PARTICIPANTS

Healthy younger adults (N=28) and healthy older adults (N=21).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Spatiotemporal gait parameters, displacement of center of mass (COM), instantaneous velocity of the COM, divergence between vertical projection of the COM, and center of pressure (COP).

RESULTS

Interaction effects of age and sex were found in stride duration, COM displacement, and instantaneous velocity of the COM in the mediolateral direction. Older adults demonstrated longer stride duration with shorter double-limb stance and longer single-limb stance during stair descent. Women have significantly longer stride duration than men. The effects of sex and age were significant in the data normalized by height. Older adults and women demonstrated larger peak-to-peak COM displacement, peak instantaneous velocity of the COM, and COM-COP divergence than the younger individuals and men, respectively. Peak instantaneous velocity of the COM was significant different in most pairwise comparisons, but the COM-COP divergence was significantly different in several comparisons.

CONCLUSIONS

This study examined the COM and COP parameters to quantify dynamic stability during stair descent across sex and age. Although older women descended stairs successfully, they demonstrated differences in control of instantaneous velocity of the COM compared with the other participants. Dynamic instability could be detected by examining the control of instantaneous velocity of the COM. In developing a better understanding of the balance control of stair descent in healthy older adults, aging patients with various pathologies can be better assessed, appropriately treated, and provided with proper assistive devices.

The influence of peripheral neuropathy, gender, and obesity on the postural stability of patients with type 2 diabetes mellitus

AIM

To assess the influence of peripheral neuropathy, gender, and obesity on the postural stability of patients with type 2 diabetes mellitus.

METHODS

151 patients with no history of otology, neurology, or orthopaedic or balance disorders accepted to participate in the study. After a clinical interview and neuropathy assessment, postural stability was evaluated by static posturography (eyes open/closed on hard/soft surface) and the "Up & Go" test.

RESULTS

During static posturography, on hard surface, the length of sway was related to peripheral neuropathy, gender, age, and obesity; on soft surface, the length of sway was related to peripheral neuropathy, gender, and age, the influence of neuropathy was larger in males than in females, and closing the eyes increased further the difference between genders. The mean time to perform the "Up & Go" test was 11.6 ± 2.2 sec, with influence of peripheral neuropathy, gender, and age.

CONCLUSION

In order to preserve the control of static upright posture during conditions with deficient sensory input, male patients with type 2 diabetes mellitus with no history of balance disorders may be more vulnerable than females, and obesity may decrease the static postural control in both males and females.

Effect of blindfolding on centre of pressure variables in healthy horses during quiet standing

In a standing horse the centre of pressure (COP), measured as the resultant vertical ground reaction force (GRF) of all supporting limbs, is adjusted in response to visual, vestibular and proprioceptive information. Stabilographic analysis measures balance by tracking COP movements in the horizontal plane. Loss of visual input affects stability of balance in people and has clinical implications in that instability inherent in some neurological diseases increases with the eyes closed. The objectives of this study were to evaluate the visual contribution to postural stability in horses. The hypothesis was that the magnitude and variability of postural sway variables increases when visual input is removed. Vertical GRFs were measured using two synchronized force plates and COP movements were tracked in 20 horses as they stood without visible movements of the hooves, head or neck. Three trials of 60 s duration were recorded under sighted and blindfolded conditions. Stabilographic variables (craniocaudal and mediolateral COP amplitudes, velocities and mean power frequencies and their within-trial variabilities) were calculated and compared using univariate analysis of variance. Compared with the sighted condition, blindfolding increased the magnitude and the within-trial variability of craniocaudal and mediolateral COP amplitudes and mediolateral COP velocity. The findings indicated that loss of visual input had more effect on the measured COP variables in the time domain (amplitudes, velocities) than in the frequency domain (mean power frequency). The effects of blindfolding on postural stability should be further investigated as part of a diagnostic approach to the evaluation of balance in horses with neurological impairment.

Comparação das inclinações lateral e anteroposterior no equilíbrio estático entre jovens, adultos e idosos

INTRODUÇÃO: Com o aumento da população idosa, fica evidente a importância de compreender e explorar o processo de envelhecimento humano, o qual acarreta transformações morfológicas e funcionais. OBJETIVOS: Avaliar e comparar as inclinações anteroposterior e lateral do centro de gravidade por faixas etárias. MÉTODOS: Estudo transversal e exploratório. Fizeram parte da pesquisa 135 sujeitos, separados em faixas etárias: Grupo 1: 20-29 anos (n=26), Grupo 2: 30-39 anos (n=26), Grupo 3: 40-49 (n=25), Grupo 4: 50-59 anos (n=30) e Grupo 5: >60 anos (n=28). Esses sujeitos foram selecionados de acordo com o escore do Miniexame de Estado Mental e pela capacidade de permanecer em pé por, pelo menos, 90 segundos. As posturas foram avaliadas por meio do software de avaliação postural (SAPO). As comparações entre os valores de inclinações dados pelo SAPO foram feitas pelo teste de Mann-Whitney (comparação par-a-par), sendo aceito um valor de p<0,05 como significante. RESULTADOS: Na comparação da média da assimetria frontal entre as faixas etárias, observa-se maior lateralização com o avançar da idade, com valores significativos nos grupos 50-59 e >60 anos. Na comparação da média da assimetria sagital entre as faixas etárias, valores são significativos no grupo dos >60 anos. CONCLUSÕES: Após avaliar e comparar as assimetrias sagitais e frontais, pode-se apontar que na medida em que a idade avança, há tendência ao aumento de suas projeções anteriores e laterais comparadas ao centro de gravidade.

Validity and reliability of wii fit balance board for the assessment of balance of healthy young adults and the elderly

[Purpose] Balance is an integral part of human ability. The smart balance master system (SBM) is a balance test instrument with good reliability and validity, but it is expensive. Therefore, we modified a Wii Fit balance board, which is a convenient balance assessment tool, and analyzed its reliability and validity. [Subjects and Methods] We recruited 20 healthy young adults and 20 elderly people, and administered 3 balance tests. The correlation coefficient and intraclass correlation of both instruments were analyzed. [Results] There were no statistically significant differences in the 3 tests between the Wii Fit balance board and the SBM. The Wii Fit balance board had a good intraclass correlation (0.86–0.99) for the elderly people and positive correlations (r = 0.58–0.86) with the SBM. [Conclusions] The Wii Fit balance board is a balance assessment tool with good reliability and high validity for elderly people, and we recommend it as an alternative tool for assessing balance ability.

Measuring regularity of human postural sway using approximate entropy and sample entropy in patients with Ehlers-Danlos syndrome hypermobility type

Ligament laxity in Ehlers-Danlos syndrome hypermobility type (EDS-HT) patients can influence the intrinsic information about posture and movement and can have a negative effect on the appropriateness of postural reactions. Several measures have been proposed in literature to describe the planar migration of CoP over the base of support, and the most used in clinical field are the CoP excursions in antero-posterior and medio-lateral direction. In recent years a growing number of studies have been designed to explore the complexity of the COP trajectories during quiet standing. We assessed 13 adults with EDS-HT (EDSG) and 20 healthy adults (CG) during static posture, evaluating the CoP using time and frequency domain analysis and entropy analysis (SampEn and ApEn parameters). Higher values of CoP displacements in medio-lateral and anterior-posterior directions for EDSG than CG were found; no differences were observed in CoP frequency. The entropy analysis showed lower value for EDSG than CG, pointing out the needing of EDSG to concentrate more attention on postural control, loosing complexity and reflecting a less automatized postural control.

Dynamic Balance Differences as Measured by the Star Excursion Balance Test Between Adult-aged and Middle-aged Women

Background:

Middle-aged women have less postural control than younger women. The Star Excursion Balance Test is a functional and inexpensive postural control measurement tool that is sensitive to age-related changes in balance.

Hypothesis:

The middle-aged females will experience lower excursion scores compared with the younger women.

Methodology:

Fifty-three healthy, recreationally active women were divided into 2 groups: adult-aged (n = 29; age range, 23-39 years) and middle-aged (n = 24; age range, 40-54 years). Each participant performed 3 reaches for 3 trials (anteromedial, medial, posteromedial) in a randomized order. The 3 reach trials were converted to a normalized value (percentage of participant’s height) and assessed as an overall mean for the 1-way analysis of variance. Intraclass correlation coefficients and 95% confidence intervals were calculated.

Results:

No differences were found for body mass index and height; however, age was different between groups (P < 0.01). Intraclass correlation coefficient^2,3 values for the 3 directions ranged from 0.72 to 0.97. The adult-aged women were able to reach farther in all 3 directions when tested with the Star Excursion Balance Test (6.8-7.6 cm, P < 0.05).

Conclusion:

Lower postural control scores based on the Star Excursion Balance Test were found for the older women. The younger women were able to reach approximately 7 cm farther during the anterior, anteromedial, and posteromedial excursions.

Can a simple balance task be used to assess fitness for duty?

Human fatigue, caused by sleep loss, extended wakefulness, and/or circadian misalignment, is a major cause of workplace errors, incidents and accidents. In some industries, employees are required to undertake fitness for duty testing at the start of a shift to identify instances where their fatigue risk is elevated, so that minimisation and/or mitigation strategies can be implemented. Postural balance has been proposed as a fitness for duty test for fatigue, but it is largely untested. Therefore, the purpose of this study was to examine the impact of sleep loss, extended wakefulness and circadian phase on postural balance. Fourteen male participants spent 10 consecutive days in a sleep laboratory, including three adaptation days and eight simulated shiftwork days. To simulate a quickly rotating roster, shiftwork days were scheduled to begin 4h later each day, and consisted of a 23.3-h wake episode and a 4.7-h sleep opportunity. Every 2.5h during wake, balance was measured while standing as still as possible on a force platform with eyes open for one minute, and eyes closed for one minute. Subjective sleepiness was assessed using the Karolinska Sleepiness Scale. Core body temperature, continuously recorded with rectal thermistors, was used to determine circadian phase. For measures of postural balance and subjective sleepiness, data were analysed using three separate repeated measures ANOVA with two within-subjects factors: circadian phase (six phases) and prior wake (nine levels). For subjective sleepiness, there was a significant effect of prior wake and circadian phase. In particular, sleepiness increased as prior wake increased, and was higher during biological night-time than biological daytime. For the eyes open balance task, there was no effect of prior wake or circadian phase. For the eyes closed balance task, there was a significant effect of circadian phase such that balance was poorer during the biological night-time than biological daytime, but there was no effect of prior wake. These results indicate that postural balance may be a viable tool for assessing fatigue associated with time of day, but may not be useful for assessing fatigue associated with extended hours of wake.

Factors affecting test results and standardized method in quiet standing balance evaluation

Objective

To identify factors affecting test results of the quiet standing balance evaluation conducted by posturography and to investigate the standardized method by comparing results according to feet width.

Method

The study cohort consisted of 100 healthy individuals. We assessed the quiet standing balance of subjects by using 3 different methods: standing on a force plate with feet width the same as shoulder width (test 1); with feet width the same as half the shoulder width (test 2); with feet width determined by the subject's comfort (test 3). Subjects underwent each test with their eyes open and closed for 30 seconds each time. Parameters for measuring standing balance included the mean mediolateral and anteroposterior extent, speed, and the velocity moment of center of pressure (COP) movement.

Results

All parameters showed better results when the subject's eyes were open rather than closed, and the mean AP extent and speed increased as the age of the subjects increased (p<0.01). However, there was no significant correlation between height and the study parameters, and no differences between men and women. Mean mediolateral extent and speed were significantly longer and faster in test 1 compared with tests 2 and 3 (p<0.01). The results of test 2 were better than the results of test 3, but the difference was not statistically significant.

Conclusion

COP movements increased with age and when subjects closed their eyes in an evaluation of quiet standing balance conducted by posturography. Gender and height did not affect results of the test. We suggest that an appropriate method for conducting posturography is to have the subject stand on a force plate with their feet width the same as half the shoulder width, because this posture provided relatively accurate balance capacity.

Comparison of the body-sway characteristics of young adults compared to healthy elderly and elderly with equilibrium disorder

The study compared body-sway characteristics of 380 young adults, 342 generally healthy elderly without disequilibrium disorders, and a group of 33 elderly with disequilibrium disorders. Center of foot pressure (COP) was measured for 1 min. using an Anima's stabilometer G5500 with a data sampling frequency of 20 Hz. Four high reliability measures were used to evaluate body sway (unit time sway, front-back sway, and a left-right sway, and high frequency band power). Unit time sway, left-right sway, and high frequency band power were significantly larger for the group of elderly with disequilibrium disorders, and smaller for the healthy elderly people and young adults, in that order. Front-back sway was significantly larger in the elderly with disequilibrium disorders and healthy elderly than in young adults. The elderly with disequilibrium disorders had a larger and faster sway than young adults as well as the healthy elderly, particularly in the left-right direction. It appears aging was specifically associated with larger influence on the front-back sway.

Redução do limite de estabilidade direção-específica em indivíduos leve a moderadamente afetados pela doença de Parkinson

A instabilidade postural na doença de Parkinson (DP) tem sido associada a uma diminuição do limite de estabilidade (LE) na direção ântero-posterior (AP). Entretanto, ainda que possíveis alterações do LE na direção látero-lateral (LL) tenham sido sugeridas, tal direção não tem sido avaliada nos estudos com DP, principalmente quando o teste de limite de estabilidade (TLE) envolve movimentos intencionais que deslocam o centro de massa corporal (CMC). O objetivo do presente estudo foi investigar o LE na postura de pé durante movimentos voluntários que promovem deslocamento do CMC nas direções AP e LL de indivíduos com e sem a DP. Doze indivíduos com DP (Hoehn & Yahr=II, III) e 12 sem a doença realizaram o TLE nos sentidos anterior, posterior, direito e esquerdo. A velocidade de movimento (VM), excursão máxima (EM) e o controle direcional (CD) do CMC foram avaliados em cada sentido. Os indivíduos com DP foram significativamente mais lentos em todos os sentidos de deslocamento do CMC (p<0,05). Não houve diferença significativa na EM e CD no sentido anterior entre os grupos (p>0,05). Por outro lado, a EM e CD do CMC foram menores para o grupo DP no sentido posterior (P) e na direção LL (p<0,05). Indivíduos leves a moderadamente afetados pela DP apresentaram redução do LE no sentido P e na direção LL quando comparados ao grupo controle. Os resultados sugerem que tal direção e sentido devam ser treinados em ortostatismo, com movimentos que deslocam voluntariamente o CMC, desde fases iniciais da DP.

Physical aspects of healthy aging: assessments of three measures of balance for studies in middle-aged and older adults

Objectives. To investigate the reliability and correlations with age of the balance components of the EPESE, NHANES, and the Good Balance Platform System (GBPS) in a normal population of adults. Design. Cross-sectional. Setting. Urban Medical Center in the Pacific. Participants. A random sample of 203 healthy offspring of Honolulu Heart Program participants, ages 38–71. Measurements. Subjects were examined twice at visits one week apart using the balance components of the EPESE, NHANES, and the good balance system tests. Results. The EPESE and NHANES batteries of tests were not sufficiently challenging to allow successful discrimination among subjects in good health, even older subjects. The GBPS allowed objective quantitative measurements, but the test-retest correlations generally were not high. The GBPS variables correlated with age only when subjects stood on a foam pad; they also were correlated with anthropometric variables. Conclusion. Both EPESE and NHANES balance tests were too easy for healthy subjects. The GBPS had generally low reliability coefficients except for the most difficult testing condition (foam pad, eyes closed). Both height and body fat were associated with GBPS scores, necessitating adjusting for these variables if using balance as a predictor of future health.

Postural analysis in time and frequency domains in patients with Ehlers-Danlos syndrome

The goal of this work is to analyze postural control in Ehlers-Danlos syndrome (EDS) participants in time and frequency domain. This study considered a pathological group composed by 22 EDS participants performing a postural test consisting in maintaining standing position over a force platform for 30s in two conditions: open eyes (OE) and closed eyes (CE). In order to compare pathological group we acquired in the same conditions a control group composed by 20 healthy participants. The obtained center of pressure (COP) signal was analyzed in time and frequency domain using an AR model. Results revealed differences between pathological and control group: EDS participants pointed out difficulties in controlling COP displacements trying to keep it inside the BOS in AP direction and for this reason increased the use of ML mechanism in order to avoid the risk of fall. Also in CE conditions they demonstrated more difficulties in maintaining posture revealing the proprioceptive system is impaired, due to ligament laxity that characterized EDS participants. Frequency domain analysis showed no differences between the two groups, affirming that the changes in time domain reflected really the impairment to the postural control mechanism and not a different strategy assumed by EDS participants. These data could help in decision-making process to establish a correct rehabilitation approach, based on the reinforcing of muscle tone to supply the ligament laxity in order to prevent risks of falls and its consequences.