Sway Area Research Articles

Dual-Task Cost Effects on Static Posture Control Parameters and Choice Reaction Time in Individuals With and Without Intellectual Disabilities.

This study aimed to evaluate the effect of age and intellectual disability (ID) on postural balance parameters, dual-task cost (DTC), and choice reaction time (CRT). Fifty-eight individuals with ID and 55 peers without ID performed a postural stance balance task under two conditions: a single task with eyes open and dual task involving an additional cognitive task (light sequence). Four postural balance parameters (total displacement, total sway area, mediolateral, and anteroposterior dispersion), cost of the dual task ([DTC%] = [(single-task performance - dual-task performance)/single-task performance] × 100), and CRT were recorded, calculated, and analyzed. All postural control parameters reflected poorerperformance during the dual-task condition, nevertheless, DTC was significantly higher only in individuals with ID and only for the total sway area, F(1, 111) = 5.039, p = .027, and mediolateral dispersion, F(1, 111) = 6.576, p = .012. CRT was longer in individuals with ID compared with the individuals without ID, F(1, 111) = 94.979, p ≤ .001, while age did not have a significant effect on the DTC nor on the CRT, F(1, 111) = 0.074, p = .786. In conclusion, an additional cognitive task during the postural balance task had a detrimental effect on various postural balance parameters, leading to increased DTC in terms of total sway area, mediolateral dispersion, and prolonged CRT in individuals with ID.

Postural Sway Characteristics in Static Balance Control of Youth Female Soccer Players

Purpose: Balance control, particularly in uni-lateral domain, is essential in soccer. Majority of the existing studies examined dynamic balance via clinical tools, and primarily involved male players. Thus, the purpose here was to examine the nature of Center of Pressure (COP) postural sway in youth female players across bipedal and unipedal conditions Methods: Sixteen pre-adolescent female competitive players (age 12.4±21.40 years) were asked to stand on a force plate in bi-pedal stance with the dominant and non-dominant legs respectively. Three, 10 second trials were carried out for each condition. Results: As expected, across the four COP measures bi-pedal stance resulted in least sway (P= .05). However, the subsequent analysis showed different center of pressure (COP) profiles in the dominant versus non-dominant condition across COP velocity (P= .003), path length (P= .001) and anterior-posterior (AP) sway (P= .003), with sway area revealing no statistical differences (P= .821). In addition, the analysis of stabilograms confirmed that in the non-dominant condition the pronounced COP oscillations were of lower amplitude and frequency as compared to the dominant leg. Conclusions: Overall, postural asymmetry was found as the sway characteristics on both legs differed, with dominant side exhibiting more sway and faster COP oscillations. In line with the inverted pendulum model, this may be due to less than optimal ability to modulate muscle torques generated at the ankle. It is hypothesized that the postural asymmetry between the dominant and non-dominant legs may result from muscular asymmetries that have been often reported in youth soccer players, as a result of their pronounced foot dominance.

TRANSCRANIAL DIRECT CURRENT STIMULATION MODULATES BRAIN ACTIVITY DURING DUAL-TASK STANDING IN OLDER ADULTS

Abstract In older adults, performing an attention-demanding cognitive task while standing comes with a ‘cost’ (i.e., decrement) to postural control. Transcranial direct current stimulation (tDCS) designed to facilitate the excitability of the left dorsal-lateral prefrontal cortex (L-DLPFC) and motor cortex (M1) mitigates this dual-task cost (DTC). The effects of tDCS on underlying brain activity measured by electroencephalography (EEG) during dual-tasking, however, is unknown. We hypothesized that tDCS would decrease the DTC of EEG-measured alpha and gamma power, as these frequencies have been linked to attentional processing and their attenuation is believed to reflect more efficient and/or effective postural control. Thirty participants received 20-minutes of tDCS targeting the L-DLPFC and M1, or sham (i.e., control) stimulation, in random order, on two separate visits. Before and immediately after each stimulation, EEG and postural sway area were recorded as participants completed trials of standing with and without verbalized serial subtractions. EEG alpha and gamma power were derived from channels corresponding to the L-DLPFC and M1 areas. The DTC (absolute change from single to dual-tasking) for both EEG and sway outcomes were calculated. tDCS, compared to sham, decreased the DTC to gamma power (p=0.04) and sway area (p=0.04). No pre-to-post stimulation changes were observed for alpha power (p=0.42). Participants who demonstrated a greater decrease in the DTC to gamma power after tDCS exhibited a greater reduction (improvement) in the DTC to sway area (r=0.66, p=0.002). The results suggest that the tDCS-induced changes in gamma-frequency activity were associated with improved dual-task standing balance in older adults.

Verbal Encouragement Provokes Significant Increases in Maximal Volitional Dynamic Postural Sway

Limits of Stability protocols are typically target-oriented, leaving volitional aspects of control unobservable. A novel unconstrained protocol, volitional Limits of Stability (vLOS), shows high test-retest-reliability. We tested if verbal encouragement impacts this protocol. Forty healthy young adults (age 20.1 ± .9 years) performed three trials of vLoS with instructions that were agnostic to strategy or vigor, except trial three included verbal encouragement. Total sway area was used to metric the maximum volitional dynamic sway during each 1-min trial. One-way, repeated-measures ANOVA revealed significant differences (F(2,117) = 41.56, p < 0.0001, η p 2 = 0.52) due to encouragement. Specifically, follow-up paired t-tests showed no difference in sway area between the first two trials (p = 0.61), while trial three was much larger than trials one and two (p < 0.0001). Significant, large increases in sway area with verbal encouragement indicate that top-down mechanisms should be considered in theories of postural control. As well, clinical utilization of novel vLOS should be careful with word selection and delivery of protocol instructions. HIGHLIGHTS Limits of Stability balance tests typically include a goal directed instruction and metrics. Dynamic postural sway should be tested in a task affording participant volitional control. A novel volitional Limits of Stability protocol has been developed. Maximal dynamic postural sway responds to motivating instructions. Psychological factors of postural sway control deserve further investigation.

Exploring the Nexus of lower extremity proprioception and postural stability in older adults with osteoporosis: a cross-sectional investigation.

Osteoporosis, characterized by reduced bone mass and micro-architectural deterioration, poses a significant public health concern due to increased fracture susceptibility. Beyond bone health, this cross-sectional study aimed to assess and compare lower extremity proprioception and postural stability in individuals with and without osteoporosis and to explore their correlation within the osteoporosis group. In this prospective cross-sectional study, 80 participants were divided into two groups: osteoporosis (n = 40) and control (n = 40). The demographic characteristics and clinical parameters of the participants were as follows: Age (years) - Osteoporosis group: 65.04 ± 4.33, Control group: 65.24 ± 4.63; Sex (%) - Osteoporosis group: Male 30%, Female 70%; Control group: Male 30%, Female 70%; Body mass index (kg/m2) - Osteoporosis group: 23.7 ± 3.2, Control group: 24.5 ± 4.6; T-score (Lumbar) - Osteoporosis group: -2.86 ± 1.23, Control group: 0.27 ± 0.58; T-score (hip) - Osteoporosis group: -2.28 ± 0.79, Control group: 0.68 ± 0.86. Joint Position Sense (JPS) at the hip, knee, and ankle was assessed using a digital inclinometer, and postural stability was measured using computerized force platforms. Osteoporosis participants exhibited higher errors in hip (5.63° vs. 2.36°), knee (4.86° vs. 1.98°), and ankle (4.46° vs. 2.02°) JPS compared to controls. Postural stability measures showed increased anterior-posterior sway (10.86 mm vs. 3.98 mm), medial-lateral sway (8.67 mm vs. 2.89 mm), and ellipse area (966.88 mm2 vs. 446.19 mm2) in osteoporosis participants. Furthermore, correlation analyses within the osteoporosis group unveiled significant positive associations between lower extremity proprioception and postural stability. Specifically, hip JPS exhibited a strong positive correlation with anterior-posterior sway (r = 0.493, p = 0.003), medial-lateral sway (r = 0.485, p = 0.003), and ellipse area (r = 0.496, p < 0.001). Knee JPS displayed a moderate positive correlation with anterior-posterior sway (r = 0.397, p = 0.012), medial-lateral sway (r = 0.337, p = 0.032), and ellipse area (r = 0.378, p < 0.001). Similarly, ankle JPS showed a moderate positive correlation with anterior-posterior sway (r = 0.373, p = 0.023), medial-lateral sway (r = 0.308, p = 0.045), and ellipse area (r = 0.368, p = 0.021). These findings underscore the interplay between proprioceptive deficits, compromised postural stability, and osteoporosis, emphasizing the need for targeted interventions to improve fall prevention strategies and enhance the quality of life for individuals with osteoporosis.

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

Purpose Previous studies demonstrated that providing light finger touch to a stationary object leads to reduced body sway. The focus of the current exploratory study was on the investigation of postural sway during one-leg stance when light touch is provided by the contralateral foot. Methods Eleven healthy young adults participated in the study. They stood on the top of the force platform with eyes open and on their dominant leg with no touch and with a touch from the contralateral foot applied to the stance leg. Medial arch, heel, and big toe of the contralateral foot were used to touch the medial malleolus or mid shank of the stance leg. The excursion, velocity, and sway area of the centre of pressure were obtained and analysed. Results Standing with light touch from the contralateral foot to the medial malleolus resulted in significantly smaller postural sway as compared to standing with no touch (p < 0.05). There was no difference in the study outcomes between conditions of standing with a touch applied by the medial arch, heel, or big toe to the stance leg. Conclusions The results of the study suggest that the application of light touch provided by a contralateral foot could be an effective strategy for enhancing body stability when no external support is available. The study outcome provides a foundation for future studies exploring ways to enhance balance control during one-leg stance.

Evaluation of postural stability under single and dual task conditions in individuals with and without intellectual disability

Background: The aim was to investigate how varying levels of intellectual disability (ID) impact postural stability parameters and response reaction time (RRT). Method: Fifty-nine individuals with low and moderate levels of ID and 55 sex- and age-matched peers without ID performed a bipedal standing postural control task while having their (I) eyes open [OE], (II) eyes closed [CE], and (III) while performing a secondary cognitive task- pressing a trigger button while maintaining still stance (dual task, DT). Seven postural control parameters (total, mediolateral and anteroposterior displacement, sway area, sway mean velocity, mediolateral dispersion, and anteroposterior dispersion) during each experimental condition as well as the RRT during the DT were recorded. Results: The results revealed that (I) CE and DT partially affected postural control parameters when compared to OE condition (in 13 and in 3 out of 21 pairwise comparisons, respectively), (II) individuals with ID had poorer postural control than peers without ID during the OE and DT conditions (p ≤ 0.05), but not during the CE condition (except for the larger total displacement observed in participants with moderate disability compared to participants without ID, p ≤ 0.05), (III) RRT was longer in individuals with ID compared to the group without ID (p ≤ 0.001), and (IV) no postural control parameter (p ≥ 0.05) nor RRT (p = 0.138) revealed differences between the participants with low and moderate levels of ID. Conclusions: These findings suggest that individuals with ID present reduced performance in the postural control parameters especially when they need to respond to DT compared to individuals without ID.

Controlling posture to see the world: The integration of visual task demands and postural sway in sitting and standing infants

Our ability to integrate posture with visually demanding tasks is a critical aspect of motor behavior flexibility. When looking at a small object, excessive body movements impair an individual’s ability to visually attend to the object. To overcome this problem, we adjust our postural sway to successfully focus on the object. The goal of the current study was to assess whether infants also adjust postural sway when engaged in a challenging visual task. The participants, 19 independently sitting infants (Sitters) and 21 newly independently standing infants (Standers), sat or stood on a force plate while viewing differently sized images displayed on a monitor (smaller images: 8 × 6.5 cm or 3 × 3 cm; larger images: 13 × 16 cm or 13 × 13 cm). Regardless of image size, Standers were less stable than Sitters with larger sway areas and faster sway velocities. Both Sitters and Standers adjusted sway area but not sway velocity, based on image size. Sitters and Standers differed in how they controlled sway dynamics. Standers but not Sitters altered sway dynamics based on image size. Overall, infants used posture-specific adaptive control strategies to make fine-grained adjustments based on image size. The development of the ability to integrate posture with a visually demanding task further emphasizes the capability of advanced complex motor behaviors during infancy, enabling infants to flexibly attend to important aspects of their environment at different postural positions.

THE EFFECTIVENESS OF DIFFERENT HANDSTAND PLACEMENT TECHNIQUES IN HANDSTAND BALANCE CONTROL AND GENDER DIFFERENCESDSTAND BALANCE CONTROL AND GENDER DIFFERENCES

The purpose of the study was twofold: (a) to examine the impact of various finger placements and utilization on the quality, control, and overall efficiency of handstand performance, and (b) to investigate potential gender differences in relation to these factors. Thirty-one young competitive gymnasts (15 males; age: 12.60 ± 2.08, and 16 females; age: 13.31 ± 2.21) participated in this study. A portable posturographic digital platform was used to record hand area (cm²), maximal pressure (kPa), CoP (center of hand pressure) sway area (mm²), CoP linear distance displacement (mm) and CoP velocity. Derived data were analyzed in an integrated software module (Foot Checker, version 4.0). The intra-class correlation coefficient and the coefficient of variation supported the reliability of the measurements. One-way MANOVA showed better balance control for all gymnasts for the handstand with flat palms and joined and fully stretched fingers, followed by that of flat palms and wide open and fully stretched fingers, and wide flat palms and open and flexed fingers. Results from one-way MANOVA indicated no differences between males and females in age, training age, body mass, height, and body mass index. With control for the effects of age, training age, personal characteristics and hand area of support in place, females had better balance control compared to males based on differences in CoP sway area, CoP linear distance displacement, and CoP velocity. Despite the study's limitations, the findings contribute to the existing literature on balance control techniques in handstands in relation to gender differences. The study provides recommendations for more effective training for coaches and suggests avenues for future research.

Static posturography analysis for postural instability in patients with Parkinson’s disease

Background Parkinson’s disease (PD) is initially characterized by a rigid-akinetic syndrome and later by the development of postural instability. This condition often leads to balance impairments, potentially resulting in postural deformities and foot asymmetry. This study aimed to assess balance changes in PD patients. Methods We evaluated 56 PD patients and 30 controls using static posturography. The variables examined included foot type, the primary region of body weight distribution on the plantar surface, statokinesigram (center of pressure [COP]), and stabilogram (COP in the X- and Y-axes). Results PD patients exhibited a high prevalence of pes cavus (92.8%) (p < 0.001) and greater weight distribution toward the hindfoot. In all assessments, COP sway areas were significantly larger in PD patients (p < 0.001). The total COP area increased in the non-fall group during the foot parallel assessment and in the X-axis in the fall group with eyes open (p = 0.046) and closed (p = 0.023). Significant correlations between body weight discharge on the plantar area and COP sway were observed, particularly in the non-postural instability group in the COP X-axis with feet parallel and eyes open on the more rigid limb and in the postural instability group in the Y-axis with feet parallel and eyes open on the more rigid limb and with eyes closed bilaterally. Conclusion Progressive rigidity may disrupt compensatory mechanisms, altering foot morphology, shifting body weight discharge posteriorly, and increasing COP sway. This cascade of events results in impaired balance and an elevated risk of falls.

Wearable sensors-based postural analysis and fall risk assessment among patients with diabetic foot neuropathy

AimsTo investigate the cross-sectional association between deep and superficial diabetic neuropathy, postural impairment assessed by wearable inertial sensors, and the risk of fall among patients with diabetic foot. MethodsDiabetic patients attending a University Podiatric Clinic were evaluated for the presence of deep and superficial peripheral neuropathy in sensory tests. Postural impairment was assessed using a wearable inertial sensor, and the evaluation of balance/gait and risk of fall was determined by the Tinetti Scale and Downton Index, respectively. Glycemic control was measured by glycated haemoglobin concentration and fasting glycaemia.The postural parameters measured were the anteroposterior and medio-lateral sway of the center of mass (CoM) and the sway area (area traveled by the CoM per second). The results were analyzed through a logistic regression model to assess those posture variables mostly significantly associated with neuropathy and risk of fall scales. ResultsA total of 85 patients were evaluated. Spearman's rank correlation coefficients showed a strong and significant relationship (p < 0.05) between deep diabetic neuropathy assessed by Semmes-Weinstein monofilament, diapason and biothensiometer and postural alterations, whereas no significant correlations between superficial (painful sensitivity) neuropathy and the postural parameters. The sway path of the displacement along the anterior-posterior axis recorded during tests performed with eyes open and feet close together were significantly (p < 0.05) correlated with a poor glycemic (glycated haemoglobin concentration) control and each other with all diabetic neuropathy tests, fall risk scales, muscular weakness, ankle joint limitation and history of ulcers. ConclusionsThe results support the existence of a strong association between alterations of the deep somato-sensitive pathway (although depending on the tool used to measure peripheral neuropathy), glycemic control and balance impairments assessed using a wearable sensors. Wearable-based postural analysis might be part of the clinical assessment that enables the detection of balance impairments and the risk of fall in diabetic patients with diabetic peripheral neuropathy.

Modern smartphone usage can negatively impact postural balance while standing on dynamically challenging grounds

BackgroundWhile several studies have explored the impacts of smartphone usage on postural balance, their tasks are limited to texting or calling, and the studies were performed on rigid ground. Research questions1.How does modern smartphone usage, specifically taking selfies or posting statuses on social media, affect balance?2.How does their interaction with challenging ground conditions affect balance? MethodsSixteen healthy young adults were recruited to perform two smartphone tasks: taking selfies and posting statuses on social media; participants were standing on four different grounds: rigid, foam-based compliant, robot-simulated compliant, and robot-simulated oscillatory grounds. The center-of-pressure (CoP) under each foot was recorded via force plates and the net CoP was calculated. Temporal, spatial, and control aspects of postural balance were analyzed by virtual time-to-contact (VTC), CoP path length (PL) and sway area (SA), and switching rate (SR), respectively. Two-way repeated measures analysis of variance (ANOVA) tests were performed for each dependent variable to compare the mean differences between smartphone tasks and ground conditions and their interaction effect. Paired t-tests with Bonferroni correction were used to determine significant differences in post-hoc analyses. ResultsVTC decreased significantly whereas CoP PL and SA increased significantly during smartphone usage (all p-values <0.001). Interaction effects between task and ground condition (all p-values <0.001) were observed in all measures but SR, implying that the effect of smartphone usage on postural balance can significantly change depending on the ground condition. SignificanceThese results highlight the potential fall risks due to the impact of modern smartphone usage on standing balance. Understanding the effect of smartphone usage on standing balance and the interaction effect with various ground conditions opens the door for potential balance assistive devices and mobile phone applications to minimize falls.

Comparison of Pre- and Postoperative Motor-proprioceptive Abilities in Patients with Gonarthrosis.

Both surgeons and patients want to achieve a high level of satisfaction and the best possible functional results within a short time after knee TEP surgery. By using a tool that digitally records various measurement parameters of balance and motor function preoperatively and postoperatively on a mobile basis and with little time expenditure, progressive results can be compared. Individual factors can thus be determined and these can influence the progress in regeneration and training progress perioperatively.In a prospective study, 100 patients before and 66 patients after installation of a cement-retained knee TEP were evaluated for the following parameters: balance, maximum strength, and power. All measurements were performed with the KMP measurement platform from MotoSana. The second measurements were performed in each case after a standardised follow-up treatment.It was shown that there are significant relationships between personal factors such as age, height, body weight and with baseline values and performance measures: maximum strength and power. Furthermore, it was shown that postoperative improvement could be achieved for the most part around balance support. All patients who previously had to hold on with one hand or both hands no longer needed support after surgery to maintain the single-leg stance for the specified time of 15s. For a more detailed analysis of the balance parameters, the samples were adjusted and only the patients who did not hold on for support pre- and postoperatively were counted. In patients with low and medium initial stance, the sway area increased at the second measurement session, and in patients with large sway areas, it decreased, and the stance became more stable. In the area of maximum strength and power, patients with high baseline values still had higher values after AHB compared with the other patients, but lower values compared with their own baseline values.Patients who already had very good motor skills before surgery were able to achieve a greater increase in motor skills compared to the weaker group. However, all patients failed to reach their preoperative baseline values after completion of the AHB. Deficits in balance were still detectable in all groups. By using the presented force plate, measurement-based coordinated rehabilitation procedures are possible during and after completion of the AHB. Rehabilitation with individualised improvement of balance and motor function could be expected to prevent dissatisfaction after knee arthroplasty, e.g. due to muscular imbalance in femoropatellar pain syndromes.

Quadriceps Strength, Postural Stability, and Pain Mediation in Bilateral Knee Osteoarthritis: A Comparative Analysis with Healthy Controls.

Bilateral knee osteoarthritis (OA) poses significant challenges to individuals' functional abilities, including quadriceps strength, postural stability, and pain perception. Understanding the complex relationships among these factors is crucial for enhancing knee OA management strategies. The primary objective of this research is to evaluate and draw comparisons between the strength of the quadriceps and the level of postural stability in two distinct groups: individuals afflicted with bilateral knee OA and those who are healthy. Furthermore, the study seeks to examine the potential correlation between the strength of the quadriceps and the level of postural stability in individuals with knee OA. In addition to this, an investigation into the potential mediating effect of pain on the relationship between these physiological factors will also be conducted. A total of 95 participants with bilateral knee OA and 95 healthy controls were recruited. Quadriceps strength was assessed using dynamometry and postural stability was evaluated through anterior-posterior and medial-lateral sway measurements along with the ellipse area using a force plate. Pain levels were measured using the Visual Analog Scale (VAS). Mediation analysis was employed to explore the role of pain in mediating the relationship between quadriceps strength and postural stability. Statistical analyses included t-tests, Pearson correlation coefficients, and mediation analysis. Knee OA participants exhibited significantly lower quadriceps strength (1.08 Nm/kg ± 0.54) compared to controls (1.54 Nm/kg ± 0.57, p < 0.001). They also demonstrated compromised postural stability with increased anterior-posterior sway (9.86 mm ± 3.017 vs. 2.98 mm ± 1.12, p < 0.001), medial-lateral sway (7.87 mm ± 2.23 vs. 3.12 mm ± 1.34, p < 0.001), and larger ellipse area (935.75 mm2 ± 172.56 vs. 436.19 mm2 ± 135.48, p < 0.001). Negative correlations were observed between quadriceps strength and postural stability variables (r = from -0.43 to -0.51, p < 0.001). Pain significantly mediated the relationship between quadriceps strength and postural stability variables (p < 0.05). This study highlights the associations between quadriceps strength, postural stability, and pain mediation in individuals with bilateral knee OA. Our findings emphasize the need for targeted interventions addressing quadriceps weakness and compromised postural stability. Additionally, the mediation effect of pain underscores the complexity of these relationships, offering insights for more effective management strategies.

A cross-sectional study of sensory-motor neuropsychological function among sewage plant and sewage net workers exposed to hydrogen sulphide when handling wastewater.

Workers at sewage treatment plants are exposed to a complex mixture of toxins, including hydrogen sulphide (H2S). An issue of concern among sewage workers, is possible negative nervous system effects from low-level H2S exposure. Empirical neuropsychological evidence indicates both that low-dose exposure to H2S exposure affects the nervous system, and the contrary, that such exposure may facilitate nervous system function, since H2S is an endogenously produced central nervous system (CNS) gasotransmitter. The aim of this study is to describe a possible association between the H2S component of the total exposure and long-term effects on neuropsychological motor function among wastewater workers. Workers (N = 138) treating wastewater in 6 sewage-treatment plants, or in the sewer net system participated in a cross-sectional study. H2S exposure was expressed in a dichotomous exposure variable defining currently H2S-exposed (N = 112) and unexposed referent workers (N = 26), and a variable defining a job-exposure matrix for long-term total typical workplace H2S exposure. The participants went through neuropsychological tests for hand coordination, reaction time (SRT), and balance, and completed questionnaires. Pearson chi-square test or independent samples t-test was used when comparing the currently H2S-exposed workers with the unexposed control group. Multiple linear regression was used to assess associations between the independent variables age, smoking and exposure variables, and the neuropsychological tests. The analyses indicate increased SRT in the currently H2S-exposed group compared to controls (mean [SD] = 225.8 [29.9] versus 210.7 [26.3] ms, P = 0.019), and an association between increased SRT and current H2S-exposure in the total study sample (β = 14.7, P = 0.026, R2 = 0.06, P = 0.050). Blindfolded balance testing indicates a nonsignificant trend in the total study sample, of reduced balance in the highest versus lowest H2S total long-term exposure-index group (Sway area [mean {SD}, mm2: 702 [410] versus 581 [278]), and a significant association between total long-term H2S exposure and reduced balance among smokers (Sway area, mm2 [β = 38.7, P = 0.039], mean sway, mm [β = 0.3, P = 0.015]). The observed trends and associations may be due to exposure peaks in certain work operations and pinpoint the importance of minimizing and avoiding exposure peaks, also when H2S time-weighted average measurements do not exceed an occupational exposure limit of 5 ppm.

Cohort study of postural sway and low back pain: the Copenhagen City Heart Study

PurposeLow back pain is a significant health problem with a high prevalence. Studies of smaller cohorts of low back pain patients have indicated increased body sway. The present paper tests the hypothesis of an association between low back pain and postural sway in a large randomly selected population.MethodsThe current study used the fifth examination (2011–2015) of The Copenhagen City Heart Study where 4543 participated. The participants answered a self-administered questionnaire regarding pain, physical activity, smoking, alcohol consumption, education, and other lifestyle factors. Measurement of postural body sway was performed using the CATSYS system.ResultsTotally 1134 participants (25%) reported to have low back pain. Subjects with low back pain had higher sway area and sway velocity than subjects without.ConclusionWhen using multivariate statistical analysis, confounding factors such as male gender, higher age, larger body height, low education level, smoking, and low activity level explained the association between low back pain and postural sway.

Influence of age on static postural control in adults with type 2 diabetes mellitus: a cross-sectional study.

It was the aim of this study to assess static postural control characteristics in people with type 2 diabetes mellitus (T2D) of different ages using a force platform. A relationship was also established between static postural control parameters and age in this study. A total of 706 participants with T2D were included in this study. The participants were stratified into three age groups: Group 1 (<60 years old), Group 2 (60-70 years old), and Group 3 (>70 years old). Static postural control assessment during two-leg stance was performed on a force platform by all participants. The center of pressure (CoP)-related parameters were measured under two stance conditions (eyes open and closed). Kruskal-Wallis tests were applied to explore the difference among the different age groups. Multivariate regression analysis was performed to determine the relation between age and static postural control parameters. Group 1 (<60 years old) had significantly less CoP total tracking length (TTL), sway area (SA), and CoP velocity along the Y direction (V-Y) under both eyes-open and eyes-closed conditions compared with Group 2 (60-70 years old) and Group 3 (>70 years old). Group 1 (<60 years old) had significantly less CoP maximum sway length along the X direction (MSL_X) and longer tracking length each area unit (TTL/SA) under the eyes-open condition compared with Group 2 (60-70 years old) and Group 3 (>70 years old). There was a significantly positive correlation between age and the most static postural parameters such as CoP TTL, SA, MSL-X, MSL-Y, and V-Y. There was a significantly negative correlation between age and TTL/SA. This study suggested that older T2D participants had worse static postural control ability than younger ones. Most static postural parameters presented a significant correlation with age; the higher the age, the worse the static postural control.

Short-Term Cast Immobilization of a Unilateral Lower Extremity and Physical Inactivity Induce Postural Instability during Standing in Healthy Young Men.

Previous studies have reported an increased postural sway after short-term unilateral lower limb movement restriction, even in healthy subjects. However, the associations of motion limitation have not been fully established. The question of whether short-term lower limb physical inactivity and movement restriction affect postural control in the upright position remains. One lower limb of each participant was fixed with a soft bandage and medical splint for 10 h while the participant sat on a manual wheelchair. The participants were instructed to stand still for 60 s under eyes-open (EO) and eyes-closed (EC) conditions. Using a single force plate signal, we measured the center of pressure (COP) signal in the horizontal plane and calculated the total, anterior-posterior (A-P), and medial-lateral (M-L) path lengths, sway area, and mean COP displacements in A-P and M-L directions. The COP sway increased and the COP position during the upright stance shifted from the fixed to the non-fixed side after cast removal, compared to before the cast application, under both EO and EC conditions. These findings indicated that 10 h of unilateral lower limb movement restriction induced postural instability and postural control asymmetry, suggesting the acute adverse effects of cast immobilization.

Does vibration frequency and location influence the effect of neck muscle vibration on postural sway? A cross-sectional study in asymptomatic participants.

Postural control is of utmost importance for human functioning. Cervical proprioception is crucial for balance control. Therefore, any change to it can lead to balance problems. Previous studies used neck vibration to change cervical proprioception and showed changes in postural control, but it remains unknown which vibration frequency or location causes the most significant effect. Therefore, this study aimed to investigate the effect of different vibration frequencies and locations on postural sway and to serve as future research protocol guidance. Seventeen healthy young participants were included in the study. We compared postural sway without vibration to postural sway with six different combinations of vibration frequency (80, 100, and 150Hz) and location (dorsal neck muscles and sternocleidomastoid). Postural sway was evaluated using a force platform. The mean center of pressure (CoP) displacement, the root mean square (RMS), and the mean velocity in the anteroposterior and mediolateral direction were calculated, as well as the sway area. The aligned rank transform tool and a three-way repeated measures ANOVA were used to identify significant differences in postural sway variables. Neck vibration caused a significant increase in all postural sway variables (p < 0.001). Neither the vibration frequency (p > 0.34) nor location (p > 0.29) nor the interaction of both (p > 0.30) influenced the magnitude of the change in postural sway measured during vibration. Neck muscle vibration significantly changes CoP displacement, mean velocity, RMS, and area. However, we investigated and found that there were no significant differences between the different combinations of vibration frequency and location.

Standard versus innovative robotic balance assessment for people with multiple sclerosis: a correlational study

IntroductionBalance disorders are common in people with Multiple Sclerosis (PwMS) and, together with other impairments and disabilities, often prevent PwMS from performing their daily living activities. Besides clinical scales and performance tests, robotic platforms can provide more sensitive, specific, and objective monitoring. Validated technologies have been adopted as gold standard, but innovative robotic solutions would represent an opportunity to detect balance impairment in PwMS.AimStudy’s aim was to compare postural assessment of 46 PwMS with a relapsing–remitting form during static tasks performed with the novel robotic platform hunova® and the gold standard EquiTest®,MethodsPearson’s r was run on Center of Pressure (COP)-related parameters and global static balance measures computed from hunova® and EquiTest® in eyes-open (EO) and eyes-closed (EC) conditions. In addition, agreeableness level toward the use of both devices was tested through numeric rating scale.ResultsConsidering COP-related parameters, correlations were significant for all measures (p < .001). Interestingly, in EO, a strong correlation was shown for sway area (r = .770), while Medio-Lateral (ML) and Anterior–Posterior (AP) oscillation range, path length, ML and AP speed, ML and AP root mean square distance had a relatively strong association (.454 ≤ r ≤ .576). In EC, except for ML oscillation range showing a relatively strong correlation (r = .532), other parameters were strongly associated (.603 ≤ r ≤ .782). Correlations between global balance indexes of hunova® and EquiTest® revealed a relatively strong association between the Somatosensory Score in EquiTest® and the Somatosensory Index in hunova® (r = − .488). While in EO Static Balance Index from hunova® was highly correlated with Equilibrium score of EquiTest® (r = .416), Static Balance Index had a relatively strong association with both the Equilibrium (r = .482) and Strategy Score (r = .583) of EquiTest® in EC. Results from agreeableness rating scale revealed that hunova® was highly appreciated compared to EquiTest® (p = .044).Conclusionshunova® represents an innovative adjunct to standard robotic balance evaluation for PwMS. This confirms that combining traditional and robotic assessments can more accurately detect balance impairments in MS.