Center Of Pressure Oscillations Research Articles

Dual-Task Effect on Center of Pressure Oscillations and Prefrontal Cortex Activation Between Young and Older Adults

ABSTRACT Purpose: This study aimed to investigate the dual-task effect on conventional center of pressure (CoP) outcomes, CoP oscillations, and prefrontal cortex (PFC) activation between young and older adults. Methods: Fourteen healthy older adults (age: 66.25 ± 3.43 years) and another fourteen gender-matched young adults (age: 19.80 ± 0.75 years) participated in this study. Participants completed single-task and dual-task standing trials in a fixed order. The displacement of CoP and PFC activation were recorded using a Force plate and a functional near-infrared spectroscopy system, respectively. Two-way MANOVAs were used to examine the group and task effects. Additionally, the Pearson correlation analyses were used to investigate the relationship between CoP oscillations and PFC activation. Results: Our results showed a worse balance performance, greater CoP oscillations of 0–0.1 (11.03 ± 8.24 vs. 23.20 ± 12.54 cm2) and 0.1–0.5 (13.62 ± 9.30 vs. 30.00 ± 23.12 cm2) Hz in the medial-lateral direction and higher right (dorsomedial: −0.0003 ± 0.021 vs. 0.021 ± 0.021 & ventrolateral: 0.0087 ± 0.047 vs. 0.025 ± 0.045 mol/ml) and left (dorsomedial: 0.0033 ± 0.024 vs. 0.020 ± 0.025 & ventrolateral: 0.0060 ± 0.037 vs. 0.034 ± 0.037 mol/ml) PFC activation in response to a secondary cognitive task in older adults (p < .05). Older adults also showed significant positive correlations between CoP oscillations in the anterior-posterior direction and PFC activation under the single-task standing. Conclusion: These results suggest that older adults presented a loss of postural automaticity contributing to cognitive dysfunction. Moreover, heightened CoP oscillations at 0–0.5 Hz in response to a secondary cognitive task could provide evidence of a loss of automaticity, which might be associated with a greater reliance on the sensory inputs.

Dual-Task Effect on Center of Pressure Oscillations and Prefrontal Cortex Activation Between Young and Older Adults

ABSTRACT Purpose: This study aimed to investigate the dual-task effect on conventional center of pressure (CoP) outcomes, CoP oscillations, and prefrontal cortex (PFC) activation between young and older adults. Methods: Fourteen healthy older adults (age: 66.25 ± 3.43 years) and another fourteen gender-matched young adults (age: 19.80 ± 0.75 years) participated in this study. Participants completed single-task and dual-task standing trials in a fixed order. The displacement of CoP and PFC activation were recorded using a Force plate and a functional near-infrared spectroscopy system, respectively. Two-way MANOVAs were used to examine the group and task effects. Additionally, the Pearson correlation analyses were used to investigate the relationship between CoP oscillations and PFC activation. Results: Our results showed a worse balance performance, greater CoP oscillations of 0–0.1 (11.03 ± 8.24 vs. 23.20 ± 12.54 cm2) and 0.1–0.5 (13.62 ± 9.30 vs. 30.00 ± 23.12 cm2) Hz in the medial-lateral direction and higher right (dorsomedial: −0.0003 ± 0.021 vs. 0.021 ± 0.021 & ventrolateral: 0.0087 ± 0.047 vs. 0.025 ± 0.045 mol/ml) and left (dorsomedial: 0.0033 ± 0.024 vs. 0.020 ± 0.025 & ventrolateral: 0.0060 ± 0.037 vs. 0.034 ± 0.037 mol/ml) PFC activation in response to a secondary cognitive task in older adults (p < .05). Older adults also showed significant positive correlations between CoP oscillations in the anterior-posterior direction and PFC activation under the single-task standing. Conclusion: These results suggest that older adults presented a loss of postural automaticity contributing to cognitive dysfunction. Moreover, heightened CoP oscillations at 0–0.5 Hz in response to a secondary cognitive task could provide evidence of a loss of automaticity, which might be associated with a greater reliance on the sensory inputs.

Influence of Impaired Upper Extremity Motor Function on Static Balance in People with Chronic Stroke.

Stroke is a leading cause of disability, especially due to an increased fall risk and postural instability. The objective of this study was to analyze the impact of motor impairment in the hemiparetic UE on static balance in standing, in subject with chronic stroke. Seventy adults with chronic stroke, capable of independent standing and walking, participated in this cross-sectional study. The exclusion criteria included vestibular, cerebellar, or posterior cord lesions. The participants were classified based on their UE impairment using the Fugl-Meyer Assessment of Motor Recovery after Stroke (FMA-UE). A posturographic evaluation (mCTSIB) was performed in the standing position to analyze the center of pressure (COP) displacement in the mediolateral (ML) and anteroposterior (AP) axes and its mean speed with eyes open (OE) and closed (EC) on stable and unstable surfaces. A strong and significant correlation (r = -0.53; p < 0.001) was observed between the mediolateral (ML) center of pressure (COP) oscillation and the FMA-UE, which was particularly strong with eyes closed [r(EO) = 0.5; r(EC) = 0.54]. The results of the multiple linear regression analysis indicated that the ML oscillation is influenced significantly by the FMA-Motor, and specifically by the sections on UE, wrist, coordination/speed, and sensation. The hemiparetic UE motor capacity is strongly related to the ML COP oscillation during standing in individuals with chronic stroke, with a lower motor capacity associated with a greater instability. Understanding these relationships underpins the interventions to improve balance and reduce falls in people who have had a stroke.

The 'Postural Rhythm' of the Ground Reaction Force during Upright Stance and Its Conversion to Body Sway-The Effect of Vision, Support Surface and Adaptation to Repeated Trials.

The ground reaction force (GRF) recorded by a platform when a person stands upright lies at the interface between the neural networks controlling stance and the body sway deduced from centre of pressure (CoP) displacement. It can be decomposed into vertical (VGRF) and horizontal (HGRF) vectors. Few studies have addressed the modulation of the GRFs by the sensory conditions and their relationship with body sway. We reconsidered the features of the GRFs oscillations in healthy young subjects (n = 24) standing for 90 s, with the aim of characterising the possible effects of vision, support surface and adaptation to repeated trials, and the correspondence between HGRF and CoP time-series. We compared the frequency spectra of these variables with eyes open or closed on solid support surface (EOS, ECS) and on foam (EOF, ECF). All stance trials were repeated in a sequence of eight. Conditions were randomised across different days. The oscillations of the VGRF, HGRF and CoP differed between each other, as per the dominant frequency of their spectra (around 4 Hz, 0.8 Hz and <0.4 Hz, respectively) featuring a low-pass filter effect from VGRF to HGRF to CoP. GRF frequencies hardly changed as a function of the experimental conditions, including adaptation. CoP frequencies diminished to <0.2 Hz when vision was available on hard support surface. Amplitudes of both GRFs and CoP oscillations decreased in the order ECF > EOF > ECS ≈ EOS. Adaptation had no effect except in ECF condition. Specific rhythms of the GRFs do not transfer to the CoP frequency, whereas the magnitude of the forces acting on the ground ultimately determines body sway. The discrepancies in the time-series of the HGRF and CoP oscillations confirm that the body's oscillation mode cannot be dictated by the inverted pendulum model in any experimental conditions. The findings emphasise the robustness of the VGRF "postural rhythm" and its correspondence with the cortical theta rhythm, shed new insight on current principles of balance control and on understanding of upright stance in healthy and elderly people as well as on injury prevention and rehabilitation.

Возрастные особенности регуляции вертикальной позы у юношей-дзюдоистов 7–15 лет

A child’s posture regulation system develops along with the body’s growth and the maturation of the central nervous, sensory, and muscular systems. It is believed that by the age of 12, posture stability reaches an adult level and does not change significantly from then on. The authors suggested that complex coordination sports training would contribute to the development and stabilization of vertical posture regulation at an older age. The aim of this paper was to study age-related features of vertical posture regulation in judokas aged 7–15 years. Materials and methods. The subjects (n = 43) were divided into three age groups: 7–9 years, 10–12 years, and 13–15 years. Vertical posture regulation was studied using stabilometry in a standing position with eyes open and closed, on a foam mat with eyes open and in a visual biofeedback test. Results. The area and velocity of centre of pressure (COP) oscillations in all tests were lower in judokas aged 10–12 and 13–15 years compared to 7–9-year-olds; no differences were found between the athletes aged 10–12 and 13–15 years. However, the power of high-frequency COP oscillations in all tests was the lowest in 13–15-year-old athletes, indicating continuing development of postural regulation. Thus, despite complex coordination training, which has a positive effect on the system of posture regulation, static postural stability in judokas increases up to 12 years of age and then stabilizes. Detailed research is required on posture regulation in athletes in later puberty and in postpuberty.

Stabilometric Correlates of Motor and Motor Imagery Expertise.

Motor Imagery (MI) reproduces cognitive operations associated with the actual motor preparation and execution. Postural recordings during MI reflect somatic motor commands targeting peripheral effectors involved in balance control. However, how these relate to the actual motor expertise and may vary along with the MI modality remains debated. In the present experiment, two groups of expert and non-expert gymnasts underwent stabilometric assessments while performing physically and mentally a balance skill. We implemented psychometric measures of MI ability, while stabilometric variables were calculated from the center of pressure (COP) oscillations. Psychometric evaluations revealed greater MI ability in experts, specifically for the visual modality. Experts exhibited reduced surface COP oscillations in the antero-posterior axis compared to non-experts during the balance skill (14.90%, 95% CI 34.48–4.68, p < 0.05). Experts further exhibited reduced length of COP displacement in the antero-posterior axis and as a function of the displacement area during visual and kinesthetic MI compared to the control condition (20.51%, 95% CI 0.99–40.03 and 21.85%, 95% CI 2.33–41.37, respectively, both p < 0.05). Predictive relationships were found between the stabilometric correlates of visual MI and physical practice of the balance skill, as well as between the stabilometric correlates of kinesthetic MI and the training experience in experts. Present results provide original stabilometric insights into the relationships between MI and expertise level. While data support the incomplete inhibition of postural commands during MI, whether postural responses during MI of various modalities mirror the level of motor expertise remains unclear.

Bilateral symmetry of vertical time to stabilization in postural sway after double-leg landing in elite athletes with unilateral chronic ankle sprain

BackgroundLower limb asymmetry among athlete with unilateral chronic ankle instability (CAI) during bilateral landing can be a potential source of ankle sprain reinjury. The aim of study was to investigate the effect of bilateral symmetry of vertical time to stabilization (vTTS) in postural sway after double-leg landing (DLL) in elite athletes with unilateral CAI.MethodsTwenty professional players with unilateral CAI and ten healthy controls were assigned to three groups (soccer, basketball, and control groups, n = 10 each). The postural balance during DLL tasks was assessed based on center of pressure (CoP) and vTTS. Multiple analysis of variance was conducted to statistically analyse the CoP and vTTS which followed by Bonferroni’s post hoc test (P < 0.05).ResultsThe vTTS of the injured foot was significantly longer in the soccer and basketball players than in the control players (P = 0.006, p < 0.001 respectively). The intragroup comparison showed a significant difference in the vTTS of CAI and uninjured feet among the basketball players (mean difference = 1.3 s). The basketball group exhibited a worse balance in CoP oscillations results between groups.ConclusionsThe findings suggested that symmetry between double-leg vTTS values, may be important as much as the sooner vTTS in reduced CoP oscillations and enhanced balance after DLL. Balancing exercises should achieve sooner vTTS in soccer players and symmetry in the double-leg vTTS of basketball players with unilateral CAI while maintaining static balance during dynamic-to-static postural changes to reduce recurrent ankle sprain.

Stabilometric Analysis of Parkinson's Disease Patients.

Parkinson's disease (PD) is considered a movement disease; it is a progressive and degenerative neurological disorder, causing disabling motor dysfunctions. Investigate the body instability of PD patients through the stabilometry test is the aim of this study. A sample of 40 participants with PD were staged between the stages of the disease using Hoehn and Yahr Modified Scale 1.5 to 3.0 in static posture with eyes open and closed to assess stabilometry in the distance from the center of pressure (CoP), as well as anteroposterior (AP) and mediolateral axis (ML). There were found no differences in the body oscillation variables on the AP and ML axis. There was a difference in CoP displacement and oscillation speed between stage 1.5 to 3.0. It was concluded that participants with PD in stage 3.0 had greater distances from the CoP and greater speed of body sway, and that these instabilities become more evident with the progression of the disease.

Effect of PSSE on postural sway in AIS using center of pressure.

We haven't known whether the center of pressure (COP) could be considered as a better indicator in the evaluation of posture and balance change after the physiotherapeutic scoliosis specific exercise (PSSE) during level walking. The objective of this study was: 1) to determine changes in COP displacement in anterior-posterior (COP-AP) and medial-lateral (COP-ML) for AIS following the PSSE; 2) to find out COP oscillation(COP-OS) from the midline for the left and right foot; 3) to investigate max pressure at the forefoot, midfoot and hindfoot bilaterally. AIS patients with three reflective markers on their back walked on the pressure sensors embedded treadmill at 2 km/h and their trunks were also registered by DIERS Formetric 4D system. Each child received the PSSE for 12 weeks by the same physical therapist and had a dynamic pressure analysis before and after the PSSE. Six AIS children at a mean age of 13 years and with averaged major Cobb angle of 26°were enrolled. There was an increase in COP-AP (15%) and a decrease in the COP-ML (-25%) following the PSSE. COP-OS on the left foot shifted farther away from the midline (about 16%) as the right side moved closer (-1%), which becomes more symmetrical (Pre-PSSE: 0.86mm & Post-PSSE: 0.32mm). There were increased pressures on the left (35%) and right (26%) hallux after PSSE. Pressure metrics, especially including COP-ML, COP-AP, COP-OS, and peak pressures on the forefoot, may be opted as optimal predictors to posture improvements by the means of PSSE.

Initial experience of balance assessment introduces 'first trial' effects on emotional state and postural control.

Anxiety and arousal have been shown to influence balance control and, therefore, have the potential to confound balance assessment. It has been suggested that the 'first-trial' effect, where performance on the first trial of a balance task differs from subsequent trials, may be a result of participants being more anxious during their first experience of having their balance assessed. However, this remains speculative since limited work has simultaneously examined emotional state and balance control during repeated assessment of the same balance task. Determine how emotional state and standing balance control change over the course of repeated assessment. Seventy-five healthy young adults completed five 120-s quiet standing trials. Psychological state was probed at each trial using self-report measures that assessed confidence, anxiety, and attention focus. Arousal was estimated from electrodermal activity and balance control was assessed from centre of pressure (COP) measures derived from forceplate data. Repeated measures ANOVAs were conducted to determine how each of these estimates changed with repeated testing. There were significant changes in emotional state with repeated testing; self-report and autonomic measures indicated that participants were most anxious and physiologically aroused during the first trial. This emotional response diminished with repeated testing, although the greatest changes occurred from the first to second trial. Despite these changes in emotional state, only some COP outcomes significantly changed. Individuals leaned further forward during only the first trial and demonstrated higher frequency and velocity mediolateral COP oscillations during the first two trials. When balance is assessed for the first time in an unfamiliar laboratory setting, there is a transient emotional response which appears sufficient to influence some aspects of balance control. It is critical to control for these confounds when designing experiments or interventions involving balance assessment.

Stabilometric analysis as a cognitive function predictor in adults over the age of 50: A cross-sectional study conducted in a Memory Clinic

BackgroundThe aging process reduces adaptive balance responses. Two-thirds of older adults with cognitive problems suffer at least one fall every year, a rate three times higher than that observed in older adults without dementia. This cross-sectional study aims to analyze the relationship between balance and cognitive status in adults older than 50 years. MethodsIndividuals over the age of 50, who attended a Memory Clinic, were evaluated for balance changes using stabilometry, with analysis of the center of pressure (CoP). The following CoP parameters were assessed using an S-Plate pressure platform: 1) sway length, 2) sway area, and 3) anteroposterior and laterolateral sway (width, mean deviation, and speed). The individuals were evaluated with eyes open and closed for 30 s in each test. The Montreal Cognitive Assessment (MoCA) was used to assess cognitive status. ResultsEighty-seven subjects participated in the study. The average age was 67.8 years, 81.4% were female, and the average MoCA score was 19.8 points. Greater CoP oscillation was observed in the eyes closed condition, demonstrating greater postural imbalance. We found a significant and direct effect of MoCA score on the CoP area in the eyes open condition. Conclusion: The results suggest that stabilometric analysis may be a predictor of cognitive function.

Induced stabilization of center of mass decreases variability of center of pressure regardless of visual or tactile information

Traditional theories claim that center of pressure (COP) is oscillating to minimize the center of mass (COM) movements, contrary to exploratory theories which propose that COP oscillates to increase sensory information flow from the environment. The aim of this work was to better understand the underlying postural control mechanisms, specifically the interplay of COP oscillations and sensory information flow on keeping the COM stable. Eighteen volunteers took part of the experiment divided into three parts based on sensory conditions: eyes opened, eyes closed and eyes closed with lightly touching a fixed object with one finger. Throughout each part the participants had to quietly stand for 335 s. In the middle of each part, we stabilized their COM for 105 s using a robotized waist-pull system. We recorded whole-body kinematics, COP oscillations, electromyographic activity of soleus and tibialis anterior muscles and the force applied by the finger during light touch conditions. The variability of COP significantly decreased when the COM was stabilized in all sensory conditions. The interaction between sensory condition and stabilization was also significant with different decline of COP variability between quiet standing and stabilization part in all three different sensory conditions. Ankle and knee angle variability decreased significantly while the hip angle variability did not. Our findings suggest that COP is not moving to explore the environment, but to attenuate oscillations of the COM. However, possible functional aspect of movement variability to keep the COM stable still remains.

Age-associated increase in postural variability relate to greater low-frequency center of pressure oscillations

BackgroundPostural control is impaired in older adults, as evidenced from greater variability of the center of pressure (COP) during postural tasks. Although COP variability associates with low-frequency COP oscillations (<1 Hz) in young adults, it remains unknown if the age-associated increase in COP variability relates to greater low-frequency COP oscillations. Research questionDo low-frequency oscillations contribute to greater postural sway (center of pressure (COP) variability) in older adults when attempting to voluntarily maintain posture in a forward leaning position compared to young adults? MethodsSeven young (25.7 ± 4.8) and seven older (71.0 ± 7.0) adults performed a postural lean forward task and attempted to match a COP target in the anterior-posterior direction as steady as possible. We quantified the COP variability as the standard deviation (SD) of COP displacements in the anterior-posterior and medial-lateral directions and quantified the frequency modulation of COP as the power in COP displacement spectra from 0-1 Hz. ResultsWe found that older adults had significantly greater anterior-posterior SD of COP (p = 0.027) and power below 0.5 Hz (p = 0.048) than young adults, but power from 0.5-1 Hz was similar (p = 0.083). In contrast, the medial-lateral SD of COP (p = 0.5) and power from 0-1 Hz (p = 0.228) was similar for the two age groups. For both the anterior-posterior and medial-lateral direction, the SD of COP was related to low frequency oscillations below 0.5 Hz. SignificanceFor the first time, we show that the age-associated increase in postural variability relates to greater COP oscillations below 0.5 Hz.

Inspiratory muscles contributions to postural control in healthy older women

It was hypothesized that induced inspiratory muscles effort, by an acute inspiratory resistance load (IRL) use, increases the postural sway and the neuromuscular activity of postural muscles in older adults. Fifteen older women breathed spontaneously, controlled (15 cycles/minute), and with acute IRL (15 cycles/minute and target load of 30 % of maximal inspiratory pressure) in random order. The breathing tasks were performed in an orthostatic position (eyes closed) during one minute on a baropodometer plate to acquire center-of-pressure (COP) oscillations and with electromyography (EMG) recording. The root mean square (RMS) of EMG was calculated. COP oscillations were higher with IRL use than spontaneous and controlled breathing tasks, but not between spontaneous and controlled conditions. EMG activity of Tibialis anterior and Soleus muscles were higher with IRL use in comparison to spontaneous and controlled breathing conditions. In conclusion, IRL use influenced the postural control through increased postural sway and neuromuscular compensation of the lower limbs in older women.

서기 자세 유지를 위한 압력중심 이동의 특징 분석

We analyzed variables of center of pressure(COP) movement during each unipedal and bipedal stance. It was not studied yet that specific quantitative comparison of dominant feet for unipedal and bipedal stance. Healthy dextropedal adult men(n=20, age: 22.9±1.89) participated this study. COP variables of Each right foot from unipedal and bipedal stance was computed for comparison and correlation (interaction) analysis. COP variables consisted of maxima, minima, displacement, velocity, and distance. Significance level for statistics was set to .05. It was found that left and right foot during bipedal stance showed no significant difference in COP variables. Furthermore, it occurred greater perturbation at unipedal stance than bipedal stance that approx two times in mediolateral(ML) and approx 50% movement in anteroposterior(AP). More remarkably, distance of AP and ML increased along with displacement and velocity of AP in bipedal stance. And specific characteristics in which displacement and velocity are decreased along decreased sway of AP in unipedal stance were shown. Consequently, separate characteristics were shown over interactions of variables in COP oscillation from unipedal and bipedal stance.

Pulmonary Rehabilitation is Improved by In-Shoe Foot Orthosis Intervention

Some studies have found that patients with asthma have bilateral foot dorsal flexion limitations, contributing to impaired quality of life. The authors hypothesised that foot misalignments could also occur in patients with chronic obstructive pulmonary disease (COPD), and that foot orthoses could increase the motor benefits of their pulmonary rehabilitation (PR). Presented herein are the results from a nonrandomised controlled study in 40 patients with COPD. Twenty patients had foot misalignment (Group 1) and wore foot orthoses for a 1-month PR period. Their data were compared to those obtained in 20 other patients with COPD who had no foot misalignment and did not wear foot orthoses (Group 2). Bodily fatigue, 6-minute walk test (6MWT) distance, peak plantar flexion force (PFF), and oscillations of the centre of pressure (CoP) were measured. Measurements were performed prior to and following completion of PR (Groups 1 and 2), immediately after wearing the foot orthosis (Group 1), and after completion of PR plus foot orthoses (Group 1). In Group 2, PR increased the 6MWT distance, but did not increase PFF nor reduce CoP oscillations and fatigue scale. Wearing the foot orthosis for the first time significantly increased the 6MWT distance (+98+12 m). Following PR with foot orthoses (Group 1), a further increase in 6MWT distance occurred (+120+13 m), bodily fatigue was reduced, PFF increased, and CoP oscillations decreased. In patients with COPD and foot misalignment, foot orthoses enhanced the functional capacity and improved the postural control.

POSTURAL ADJUSTMENTS OF ACTIVE YOUTHS IN PERTURBATION AND DUAL-TASK CONDITIONS

ABSTRACT Introduction Cognitive components are necessary to maintain posture during external perturbations. However, few studies have investigated postural control when external perturbations are associated with a concomitant cognitive task (DT). Objectives To analyze the behavior of reactive adjustments after perturbation with different intensities and displacements in active young adults; and to analyze the influence of DT on predictive and reactive adjustments in different perturbation conditions. Methods Twenty-eight physically active young adults stood on an item of equipment that produced displacements of the base. Four experimental conditions were introduced in a single task (ST) and DT (cognitive-report how many times a pre-established number appeared in the audio): 1 (5 cm and 10 cm/s); 2 (5 cm and 25 cm/s); 3 (12 cm and 10 cm/s) and 4 (12 cm and 25 cm/s). Three attempts were carried out for each condition (total=24). Center of pressure (CoP) parameters were analyzed considering the following windows: predictive (-250 to +50 ms), reactive 1 (+50 to +200 ms) and reactive 2 (+200 to +700 ms), in comparison to the start of the CoP activity. One-way ANOVAs were performed to analyze predictive adjustments, while two-way ANOVAs with factor for task (STxDT) and condition (1x2x3x4), with repeated measurements, were performed for the reactive adjustments. Results One-way ANOVA (predictive) indicated that the subjects had higher CoP parameters in ST vs DT. In reactive adjustments 1 and 2, ANOVA indicated greater CoP parameters in condition 2 and 4 when compared to 1 and 3, and in the ST vs DT. The subjects took longer to recover stable position in conditions 1 and 3 than in conditions 2 and 4. Conclusion Perturbation intensity has a greater influence on postural adjustments to maintain balance than on magnitude. Moreover, the association of cognitive tasks with external perturbation decreases CoP oscillation. Therefore, cognitive resources play an important role in postural control after perturbation. Level of evidence III; Study of nonconsecutive patients, with no “gold” standard applied uniformly.

Adaptation of emotional state and standing balance parameters following repeated exposure to height-induced postural threat

Height-induced postural threat influences standing balance control. However, it is unknown if minimizing individuals’ emotional response to threat moderates this relationship. This study repeatedly exposed individuals to height-induced postural threat to determine if reducing the emotional response to threat influences standing balance control. Sixty-eight young adults completed a series of standing trials at LOW (0.8 m above ground, away from edge) and HIGH (3.2 m above ground, at edge) postural threat conditions. Emotional state was assessed using self-report and electrodermal measures. Standing balance was assessed through analysis of centre of pressure (COP) movement and lower leg electromyographic activity. Individuals’ emotional response to threat was attenuated following repeated threat exposure. However, threat-induced changes in standing balance were largely preserved. When initially threatened, individuals leaned backward and demonstrated smaller amplitude and higher frequency of COP adjustments; these balance outcomes did not change following repeated threat exposure. Only high frequency COP oscillations (>1.8 Hz) and ankle muscle co-contraction showed any adaptation; regression analyses showed that these behavioural adaptations were accounted for by a combination of emotional and cognitive state changes. This suggests that some threat-induced standing balance changes are more closely linked with the emotional response to threat than others, and are therefore amendable to intervention.

Motor-cognitive dual-task performance of older women evaluated using Wii Balance Board.

Single- and dual-tasks are influenced by age-related impaired postural balance. Aim of this study was to analyze the Center of Pressure (CoP) oscillation during static balance in the presence or absence of cognitive task on older women. Thirty-one healthy older women were assessed in a stand quiet position with open/closed eyes (single-task, OE and CE) and with cognitive task (dual-task, DT) through Wii Balance Board. Sway area, total displacement and CoP oscillation (CO) based on the number of times that CoP traveled through anteroposterior and mediolateral directions. Friedman test was used to compare OE, CE and DT. Dual-task interference percentage was used to quantify the cognitive load on balance whereas Spearman correlation coefficient was used to assess the association of cognitive domains and CO. The CO was significantly higher in DT than in single-tasks and participants were unable to maintain their limits of stability in mediolateral direction. The cost of DT interference was 30.5%, which is partially explained by the deviation of attention from postural control to spatial and temporal orientation. Our findings show that cognitive load during DT impairs balance in mediolateral direction, thus indicating the use of WBB to assess cognitive interference on postural control.

Changes in Spine Alignment and Postural Balance After Breast Cancer Surgery: A Rehabilitative Point of View.

Breast cancer is the most common malignant tumor in female patients in developed countries. Recent articles indicate that one-sided mastectomy or minor breast surgery to treat breast cancer can have deleterious effects on posture and the musculoskeletal system. The purpose of this study was to investigate the alterations post-breast cancer surgery of the spine alignment associated to the balance not reported by the noninvasive instrumentation. We enrolled 30 women who had undergone treatment for breast cancer (BG) and were on a waiting-list for rehabilitation treatment and a control group of 30 healthy volunteer women (CG), matched by age and body mass index. The stabilometry was performed using a force platform (Kistler Instruments, Winterthur, Switzerland) test during quiet standing with closed-eyes (EC) and open-eyes (EO), recording the position of the center of pressure (CoP) for 51.2 sec. The stabilogram or the time plot of the two coordinates, X and Y, of the CoP was obtained, which represent anteroposterior and midlateral balance. Spinal posture was measured using the Formetric-4D rasterstereographic system (DIERS, International GmbH, Schlangenbad, Germany), and thoracic kyphotic angle, lumbar lordotic angle, and surface trunk rotation were evaluated. Sixty participants were analyzed (CG:30; BG:30). For the spine rasterstereography a statistically significant difference was shown with regard to anterior–posterior flexion of the trunk major in BG; pelvic inclination and twist of half-pelvis decreased in BG; normalized lumbosacral inversion point decreased in BG; surface rotation major in BG; and lateral deviation major in BG. Compared with the values for the stabilometry test with EO and EC, a statistically significant difference was observed, respectively, for ellipse length (mm; p = 0.04) and ellipse area (mm2; p = 0.04) with EO and in ellipse area (mm2) with EC (p = 0.05), increased in BG for both conditions. No difference was shown for CoP velocity and oscillations between the groups. Breast cancer survivors after prostheses or tissue expanders for mastectomy showed a spine's misalignment present both on the sagittal plane, both on the coronal and frontal plane, increased in BG regard to anterior–posterior flexion of the trunk, surface rotation, and lateral deviation. It is associated with greater energy expenditure for the postural balance control increased in BG with a major ellipse area in EO and EC conditions and major ellipse length in EC condition.