Age-related Changes In Postural Control Research Articles

Impact of age on the postural stability measured by a virtual reality tracker-based posturography and a pressure platform system

BackgroundCenter of pressure (CoP) parameters are commonly used to evaluate age-related changes in postural control during standing. However, they mainly reflect ankle strategies and provide limited information about hip strategies, which are essential for postural control among the aged population. Body displacement at the lumbar level (LD) can be used as a proxy for hip strategies.ObjectivesWe set up a virtual reality tracker-based posturography to measure LD and compared the CoP and LD parameters in two age groups to explore the roles of ankle and hip strategies during bipedal stance.MethodsTwenty-seven older healthy participants (63.8 ± 7.1 years old) and 27 younger controls (31.7 ± 9.9 years old) performed four standing tasks with their postural steadiness measured simultaneously with both systems under four stance conditions (combination of eyes-open/eyes-closed and wide-based/narrow-based). Five parameters were calculated from the trajectories of the CoP and LD. The difference in the parameters between two groups was analyzed with the Mann–Whitney U test. The discriminative ability of the parameters from the two systems was computed by the receiver operating characteristic curve analysis and area under the curve (AUC). We also used the intraclass correlation coefficient (ICC) to assess the correlation between two measures.ResultsMost of the parameters obtained from both systems were significantly different between the younger and older groups. Mean velocity in the medial–lateral and anterior–posterior directions could effectively discriminate age-related changes, especially with the LD parameters. The receiver’s operation curve analysis gained the largest AUC (0.85 with both systems) with mean velocity in the medial–lateral direction during narrow-based standing with eyes closed. Meanwhile, we observed a low correlation between parameters obtained from the two methods in velocity measures, with the lowest ICC in the mean velocity in the medial–lateral direction in the older group (ICC = 0.34 ~ 0.41).ConclusionBoth systems could differentiate age-related changes in postural steadiness, but with dissociated information about mean velocity, especially the mean velocity in the medial–lateral direction in the older group. The results support the complimentary role of using tracker-based posturography to understand the effect of age on the mechanisms of postural control.

Age-related changes in postural control in older women: transitional tasks in step initiation

BackgroundAging, being a natural process, involves many functional and structural changes within the body. Identifying the age-related postural changes will provide insight into the role of aging on postural control during locomotion. The aim of this study was to identify age-related postural changes during a transitional task under different conditions.MethodsSixty healthy females divided into three age groups: A (50-60 y/o), B (60-70 y/o), and C (70-80 y/o). The transitional task was measured by two force platforms. The procedure consisted of three phases: quiet standing, transfer onto a second platform, and quiet standing on the second platform. Four different conditions were applied: unperturbed transfer, obstacle crossing, step-up, and step-down. Double-support time, transit time, and stability time before and after the step task were analyzed.ResultsThe transit time was longer by 30% for subjects over 70 y/o. The double-support time was longer by 11% among adults 60-70 y/o, while in people over 70 y/o it was longer by almost 50% compared to the 50-60 y/o subjects. The stability time before the transitional task was longer by 17% among adults over 60 y/o compared to middle-age subjects. The stability times before and after the transitional task were longer for adults in the 50-60 y/o category.ConclusionThe proposed procedure is adequate for assessing age-related changes in postural control while undergoing a transitional task. An analysis of the double-support time and stability time before and after the step task enabled the detection of early signs of balance changes in middle-age adults. Independent of age, the transitional task parameters changed with the increasing difficulty of the tasks.

Age-Related Changes in Postural Control in Physically Inactive Older Women.

The maintenance of postural control is influenced by the complexity of a given task. Tasks that require greater attention and cognitive involvement increase the risk of falls among older adults. The aim of the present study was to evaluate the adaptation of the postural control system to different levels of task complexity in physically inactive young and older women. A cross-sectional study was conducted with adult women classified as physically inactive based on the results of the International Physical Activity Questionnaire. The participants were 27 young (20-30 years of age) and 27 older (60-80 years of age) women. Sway velocity of the center of pressure in the anterior-posterior and medial-lateral directions was calculated using a force plate under 6 conditions: standing directly on the force plate or on a foam placed over the force plate, eyes open or closed, and dual-task complexity with and without the foam. A 2-way analysis of variance revealed that sway velocity increased in both groups when the task conditions were altered. The older women exhibited significantly greater sway velocity compared with the young women on all tasks. However, the patterns of postural control adaptation to the different levels of complexity were similar among all participants. In this study, the adaption of the postural control system to different levels of task complexity did not differ between physically inactive young and physically inactive older women. However, the physically inactive older women exhibited greater sway velocity compared with the young women.

Subjective stability perception is related to postural anxiety in older subjects

BackgroundUnder static conditions, the objective and subjective measures of postural stability correlate well. However, age-related changes in postural control and task-related anxiety may modify the relationship between these subjective and objective measures. Ultimately, patients’ symptoms represent subjective reports, thus understanding this relationship has clinical implications. AimsThis study investigates the relationship between subjective-objective measures of postural stability in dynamic conditions and whether this relationship is influenced by age or task-related anxiety. Methods50 healthy participants (aged 18–83 years) stood on a platform oscillating at variable amplitudes, with-without a fall-preventing harness to modulate task-related anxiety. Trunk sway path, hip velocity and foot lifts (objective measures) and subjective scores of instability and task-related anxiety were recorded. ResultsThe subjective perception of stability accurately matched objective body sway, following a logarithmic function profile (r2 = 0.72, p < 0.001). This function did not change significantly with age, harness or task presentation order. A strong relationship was observed between subjective measures of stability and task-related anxiety for all subjects (r = 0.81, p < 0.001). Task repetition reduced anxiety in the young, uncoupling anxiety changes from subjective instability, but not in the elderly who retained higher anxiety levels in line with subjective unsteadiness. DiscussionSubjects accurately rate their own instability during dynamic postural challenges, irrespective of age and actual fall risk. However, anxiety may selectively modulate the perception of instability in older subjects. The perception of stability relies upon the integration of sensory afferents but also recruits emotional-cognitive processes, particularly in older individuals. The use of a safety harness has no influence on subjective or objective postural stability.

Age-related changes in postural control for wearing shoes using different process of leg-raising processes in the sitting position: a pilot study.

[Purpose] Wearing shoes can be difficult for people who experience movement difficulties. This study aimed to compare young adults and senior adults while wearing shoes in order to quantify kinematic, physiological, and ergonomic points of variance. [Participants and Methods] Nine young adults (mean age, 21 years) and nine senior adults (mean age, 70 years) were included in the study. We investigated four postural combination of using hand and crossing legs used while wearing shoes: 1) time required to wear shoes, 2) the center of pressure point, 3) muscle activation within the right sartorius, the left rectus femoris, the gluteus maximus, and the internal oblique, and 4) the perceived ease of task performance via a numerical rating scale. [Results] The activities of the internal oblique and the gluteus maximus were significantly higher in senior adults than in young adults. Wearing shoes without using hands was associated with the highest value for the ease of performance among the four patterns for both groups. [Conclusion] Our results suggested that the muscles analyzed in this study were important for safety and postural maintenance while performing activities of daily living tasks in leg-raising processes in the sitting position, with lower level of muscle activity.

Sway regularity and sway activity in older adults’ upright stance are differentially affected by dual task

Age-related changes in postural control are attributed to visual, vestibular and proprioceptive dysfunctions, muscle weakness, and reduced availability of neural resources required for efficient balance control. Concurrent performance of complex cognitive tasks while standing or walking is expected to increase balance instability due to under-recruitment of brain resources and insufficient allocation of attention to the postural task. Both balance instability and attentional control of movements can, nonetheless, be determined from the center of pressure (CoP) measurements by examining the effects of dual-task on the amount of sway activity (as measured by CoP velocity − Vcop) and the statistical regularity of the CoP trajectory (the wavelet entropy of the signal − WEcop). The abovementioned characteristics were examined in the present study in a group of 13 healthy older adults. The task involved maintaining Romberg stance for 25 s with or without performing an attention demanding cognitive tasks (word memorization or mathematical counting). A linear mixed-model study was designed to analyze the extent to which sway activity can predict sway regularity. Findings from the present study showed that, on average, Vcop and WEcop were positively correlated (p = 0.014), suggesting that older individuals who exhibited greater amounts of sway (i.e., higher Vcop) also increased sway irregularity of the posturogram – as evidenced by a higher level of wavelet entropy of the CoP trajectory. Nevertheless, results of the linear mixed model showed that significant positive associations between Vcop and WEcop were found only in dual task (R ≥ 0.67, p ≤ 0.012). Furthermore, dual-task effects (% change in performance) on both sway characteristics were not significant (p > 0.1), suggesting that none of the attention demanding cognitive tasks used in the present study was sufficient to divert a critical amount of attentional resources from the postural task. Finally, performance of the mathematical counting (but not the word memorization) task was deteriorated from sitting to standing, however this effect was marginal (p = 0.075). Taken together, we proposed that while dual task could hinder balance control, postural stability may still be maintained by allocating more attentional resources to the postural task and reducing automatized control.

Age-related changes in postural control to the demands of a precision task

Optimal sensorimotor integration is needed to maintain the precision of a visuomotor postural task. Furthermore, cognitive resources have been suggested to be involved in maintaining balance, especially in older adults. This study investigated how older and younger adults differed in employing sensorimotor strategies in a dual-task situation. Older (age 65–84years) and younger adults (age 19–30years) performed a visually-based, postural tracking task in different body orientations (from 0° to 45°), which necessitated slightly different task goals. On some trials, participants performed a concurrent silent arithmetic task with the visuomotor tracking task. The results demonstrated that sensorimotor control declined with age. Older adults showed greater medial–lateral center of pressure variability compared to younger adults in the precision task. Younger adults displayed a trend to decrease anterior–posterior variability, but older adults exhibited an opposite trend when the body orientation changed from 0° to 45°. The addition of a dual-task situation decreased overall postural variability in both age groups. Age-related changes in postural control may degrade the flexible coordination of the sensory feedback and motor execution. This study suggested that medial–lateral stability may be more sensitive to this age-related decline and may be closely associated with postural instability and falls.

Elderly Use Proprioception Rather than Visual and Vestibular Cues for Postural Motor Control.

Multiple factors have been proposed to contribute to the deficits of postural control in the elderly. They were summarized as sensory, motor, and higher-level adaptation deficits. Using a model-based approach, we aimed to identify which of these deficits mainly determine age-related changes in postural control. We analyzed postural control of 20 healthy elderly people with a mean age of 74 years. The findings were compared to data from 19 healthy young volunteers (mean age 28 years) and 16 healthy middle-aged volunteers (mean age 48 years). Postural control was characterized by spontaneous sway measures and measures of perturbed stance. Perturbations were induced by pseudorandom anterior–posterior tilts of the body support surface. We found that spontaneous sway amplitude and velocity were significantly larger, and sway frequencies were higher in elderly compared to young people. Body excursions as a function of tilt stimuli were clearly different in elderly compared to young people. Based on simple feedback model simulations, we found that elderly favor proprioceptive over visual and vestibular cues, other than younger subjects do. Moreover, we identified an increase in overall time delay challenging the feedback systems stability, and a decline in the amplitude of the motor feedback, probably representing weakness of the motor system. In general, these parameter differences between young and old may result from both deficits and compensation strategies in the elderly. Our model-based findings correlate well with deficits measured with clinical balance scores, which are widely used in clinical practice.

Leisure sports and postural control: Can a black belt protect your balance from aging?

To determine potential benefits of intensive leisure sports for age-related changes in postural control, we tested 3 activity groups comprising 70 young (M = 21.67 years, SD = 2.80) and 73 older (M = 62.60 years, SD = 5.19) men. Activity groups were martial artists, who held at least 1st Dan (black belt), sportive individuals exercising sports without explicit balance components, and nonsportive controls. Martial artists had an advantage over sportive individuals in dynamic posture tasks (upright stance on a sway-referenced platform), and these 2 active groups showed better postural control than nonsportive participants. Age-related differences in postural control were larger in nonsportive men compared with the 2 active groups, who were similar in this respect. In contrast, negative age differences in other sensorimotor and cognitive functions did not differ between activity groups. We concluded that individuals engaging in intensive recreational sports have long-term advantages in postural control. However, even in older martial artists with years of practice in their sports, we observed considerable differences favoring the young.

Intra-session reliability of traditional and nonlinear time-series posturographic measures in a semi-tandem stance: A reference to age

The purpose of this study was to evaluate the intra-session reliability of traditional and nonlinear time-series center of pressure (CoP) based measures of postural sway during upright semi-tandem quiet stance in young vs. older subjects. Seventy-four healthy volunteers (40 young individuals, mean age: 27±6yrs; 34 older individuals, mean age: 79±8yrs) performed three 30-s trials of semi-tandem quiet stance on a force plate with their eyes open. Traditional posturography analysis and 4 nonlinear time-series analyses (sway density plots, diffusion plots, recurrence quantification, sample entropy analyses) were applied to the recorded CoP time series, based on which 13 traditional and 32 nonlinear time-series CoP-based measures were calculated. Significant trial-to-trial improvements (particularly between the first and second trial) were observed in the calculated CoP measures in only 2 and 4 cases in the young and older individuals respectively. Regarding the traditional CoP measures, the highest intraclass correlation coefficients (ICCaverage, i.e. ICC2,k) (0.75–0.96) and the lowest coefficients of variation (CV) (8.2–27.3%) in both age groups were observed in the mean frequency of CoP local extrema, the mean amplitude of CoP excursion, and the time-normalized CoP area, although for some of the measures we recommend an additional familiarization trial due to systematic bias. Regarding the structural mechanics CoP measures, the highest ICCa (0.70–0.94) and the lowest CVs (1.2–8.4%) in both age groups were observed in those derived from recurrence quantification and sample entropy analyses, respectively. These CoP measures could be recommended for further use in basic and clinical studies, particularly those on age-related changes in postural control during the semi-tandem quiet stance.

Age-Related Changes in Postural Control: Rambling and Trembling Trajectories

This study identified and quantified rambling and trembling properties of the postural control system of children 4-12 years of age. Forty five children of varying ages (4-, 8-, and 12-years) and 15 adults stood upright on a force plate and performed 5 trials with and 5 trials without vision with each trial lasting 30 s. Center of pressure, rambling, trembling, mean sway amplitude, and predominant frequency were obtained. Results revealed that the displacement of the center of pressure and overall rambling trajectories were age-related with younger children swaying more than older children and adults. Similarly, overall trembling trajectories for younger children were larger compared with older children and adults. These results suggested that a younger child's larger body sway mostly results from difficulties using sensory information when estimating overall body position and velocity in an upright stance and is less a result from the noise in the postural control system.

Age-related effects of a memorizing spatial task in the adults and elderly postural control

The aim of this study was to evaluate the age-related changes in postural control during a simple quiet standing task and a dual-task paradigm (applying a memory-spatial task and quiet standing).Thirty-five subjects were divided in two age-related groups: both younger (Y: 20–26 years) and older (O: 60–77 years) groups performed a simple postural task (quiet standing) and a dual-task (a visual memory task combined with quiet standing). Measures of the center of pressure (CoP) were recorded and its two components, the center of gravity (CG) and the differential CoP–CG, were evaluated.An age-related effect was observed in static postural performance during dual-tasking. Postural stability led to improved performance in younger subjects during the dual-task and but not in the elderly.Of the results suggest there is a “cognition first” principle for the younger adults, that is, the mirror image of the “posture first” principle observed in older adults under dual-tasking situations.

Study of age-related changes in postural control during quiet standing through Linear Discriminant Analysis

BackgroundThe human body adopts a number of strategies to maintain an upright position. The analysis of the human balance allows for the understanding and identification of such strategies. The displacement of the centre of pressure (COP) is a measure that has been successfully employed in studies regarding the postural control. Most of these investigations are related to the analysis of individuals suffering from neuromuscular disorders. Recent studies have shown that the elderly population is growing very fast in many countries all over the world, and therefore, researches that try to understand changes in this group are required. In this context, this study proposes the analysis of the postural control, measured by the displacement of the COP, in groups of young and elderly adults.MethodsIn total 59 subjects participated of this study. They were divided into seven groups according to their age. The displacement of the COP was collected for each subject standing on a force plate. Two experimental conditions, of 30 seconds each, were investigated: opened eyes and closed eyes. Traditional and recent digital signal processing tools were employed for feature computation from the displacement of the COP. Statistical analyses were carried out in order to identify significant differences between the features computed from the distinct groups that could allow for their discrimination.ResultsOur results showed that Linear Discrimination Analysis (LDA), which is one of the most popular feature extraction and classifier design techniques, could be successfully employed as a linear transformation, based on the linear combination of standard features for COP analysis, capable of estimating a unique feature, so-called LDA-value, from which it was possible to discriminate the investigated groups and show a high correlation between this feature and age.ConclusionThese results show that the analysis of features computed from the displacement of the COP are of great importance in studies trying to understand the ageing process. In particular, the LDA-value showed to be an adequate feature for assessment of changes in the postural control which can be related to functional changes that occur over the ageing.

An overview of age-related changes in postural control during quiet standing tasks using classical and modern stabilometric descriptors

Age-related changes in postural control during quiet standing likely result from underlying pathological conditions or from the low specificity of classical stabilometric parameters, which are vulnerable to base of support configurations and anthropometric differences. This study focuses on the identification of changes in postural control with natural aging by using conventional and recent stabilometric analysis, and on the interpretation of the stabilometric parameters according to a recently proposed framework of postural control. Quiet standing stabilometric tests were applied to 57 subjects equally divided into young, middle-aged and aged groups (19–29, 38–51 and 65–73 years, respectively) with eyes open and closed conditions. In addition to estimation of classical descriptors, center of pressure time series were approached according to a diffusion-like process and the recently proposed sway density curve. Two out of 10 estimated descriptors identified between-group differences. Aged subjects exhibited higher sway frequencies, possibly resulting from the increase of torque bursts produced by the plantar flexors, and stronger negative correlation between consecutive center of pressure displacements observed for long time intervals, likely due to higher amplitude of plantar flexors torque. Aging itself does not result in major changes of postural stability, but reflects a small increase in plantar flexion torque amplitude and frequency of torque adjustments, probably to compensate for the lower stiffness of calf muscle tendon in aged subjects.

Age-Related Changes in Postural Control Associated with Location of the Center of Gravity and Foot Pressure

The purpose of this study was to assess the limitations of the head and lumbar movements in relation to the center of gravity which is needed to maintain standing balance with aging. The subjects of the study were 22 healthy volunteers. The subjects were divided into two age categories, the young group (mean 21.7 ± 2.9 years, 7 males and 6 females); and the elderly group (mean 71.3 ± 2.6 years, 3 males and 4 females). The instruments for measuring lumbar and head movements and the center of pressure (COP) were a three-dimensional motion analysis system and a force plate. In addition, the peak foot pressure was measured during standing using the F-Scan system. The subjects were first asked to stand relaxed for 10 s. They then shifted from the starting position to the four directions (sways); anterior, posterior, right, and left. They tried to maintain standing balance at the maximal possible distance position for each sway for 10 seconds. Analyzing parameters were performed by measuring the average maximal linear displacement (cm) of the head and lumbar markers, the COP (cm), and the peak foot pressure (percent of body weight per squared centimeters; BW%/cm2) in each subject. The data of the young group for lumbar maximal displacement were greater than those of the elderly group in the anterior, posterior, and lateral sways. A significant difference between the young and elderly data was found in the posterior sway. According to the data of the head's maximal displacement, the elderly group was greater than the young group in all sways except for the anterior side. For the data of peak foot pressure in the posterior sway, the elderly group's data was greater than the young group's data. The forefoot area data of the young group was significantly greater than that of the elderly group and the heel area data of the elderly was significantly greater than that of the young group in the right sway. The results suggest that evaluating the maximal displacement of head and lumbar positions and toe's activity in the forefoot are all important factors associated with the center of gravity in healthy adults.

Age-Related Changes in Postural Control Associated with Location of the Center of Gravity and Foot Pressure

The purpose of this study was to assess the limitations of the head and lumbar movements in relation to the center of gravity which is needed to maintain standing balance with aging. The subjects of the study were 22 healthy volunteers. The subjects were divided into two age categories, the young group (mean 21.7 ± 2.9 years, 7 males and 6 females); and the elderly group (mean 71.3 ± 2.6 years, 3 males and 4 females). The instruments for measuring lumbar and head movements and the center of pressure (COP) were a three-dimensional motion analysis system and a force plate. In addition, the peak foot pressure was measured during standing using the F-Scan system. The subjects were first asked to stand relaxed for 10 s. They then shifted from the starting position to the four directions (sways); anterior, posterior, right, and left. They tried to maintain standing balance at the maximal possible distance position for each sway for 10 seconds. Analyzing parameters were performed by measuring the average maximal linear displacement (cm) of the head and lumbar markers, the COP (cm), and the peak foot pressure (percent of body weight per squared centimeters; BW%/cm2) in each subject. The data of the young group for lumbar maximal displacement were greater than those of the elderly group in the anterior, posterior, and lateral sways. A significant difference between the young and elderly data was found in the posterior sway. According to the data of the head's maximal displacement, the elderly group was greater than the young group in all sways except for the anterior side. For the data of peak foot pressure in the posterior sway, the elderly group's data was greater than the young group's data. The forefoot area data of the young group was significantly greater than that of the elderly group and the heel area data of the elderly was significantly greater than that of the young group in the right sway. The results suggest that evaluating the maximal displacement of head and lumbar positions and toe's activity in the forefoot are all important factors associated with the center of gravity in healthy adults.

Age-related changes in postural control and locomotion.

Age-related changes in both postural control and locomotion were investigated. Postural control was evaluated by magnitude of body sway for 131 healthy persons aged 21 to 84 years. Locomotion was evaluated by walking velocity for 217 healthy persons aged 21 to 88 years. Analysis showed that both abilities deteriorated for older persons and particularly age-related changes were more remarkable in locomotion.

Postural steadiness and ankle joint compliance in the elderly

Research in progress to identify and model age-related changes in postural steadiness is reviewed. In particular, research evaluating measures of postural steadiness to identify those that can be used to characterize an individual's postural steadiness based on a single eyes-open/eyes-closed test pair is discussed. The validity of a measure is determined by its intergroup sensitivity and intrasubject reliability. Efforts to evaluate the relative sensitivity of postural steadiness measures to age-related changes in postural control, the relative intrasubject reliability of postural steadiness measures, and the relation between ankle joint compliance and measures of postural steadiness in the elderly is described. >