Wyniki wyszukiwania - BazTech

1

EEG based cortical investigation for the limit of stability analysis in transfemoral amputees: A comparison with able-bodied individuals

Khajuria Aayushi, Joshi Deepak

Biocybernetics and Biomedical Engineering

|

2022

|

Vol. 42, no. 1

362--374

EN

Background: The evidences for demonstrating the contributions of the cerebral cortex in human postural control is increasing. However, there remain little insights about the cortical correlates of balance control in lower-limb amputees. The present study aimed to investigate the cortical activity and balance performance of transfemoral amputees in comparison to healthy individuals during a continuous balance task (CBT). Methods: The postural stability of the participants was defined with limit of stability parameter. Electroencephalography (EEG) data were recorded in synchronization with the center of pressure (CoP) data from eighteen individuals (including eight unilateral transfemoral amputees). We anticipated that, due to the limb loss, the postural demand of transfemoral amputees increases which significantly modulates the spectral power of intrinsic cortical oscillations. Findings: Using the independent components from the sensorimotor areas and supplementary motor area (SMA), our results present a well-pronounced drop of alpha spectral power at sensorimotor area contralateral to sound limb of amputees in comparison to SMA and the sensorimotor area contralateral to prosthetic limb. Following this, we found significantly higher (p < 0.05) limit of stability (LOS) at their sound limb than at the prosthetic limb. Healthy individuals have similar contribution from both the limbs and the EEG alpha spectral power was similar across the three regions of the cortex during the balance control task as expected. Overall, a decent correlation was found between the LOS and alpha spectral power in both amputee and healthy individuals (Pearson’s correlation coefficient > 0.5). Interpretation: By externally stimulating the highlighted cortical regions, neuroplasticity might be promoted which helps to reduce the training time for the efficient rehabilitation of amputees. Additionally, this new knowledge might benefit in the designing and development of innovative interventions to prevent falls due to lower limb amputation.

2

The stock market indexes in research on human balance

Wodarski Piotr, Chmura Marta, Gruszka Grzegorz, Romanek Justyna, Jurkojć Jacek

Acta of Bioengineering and Biomechanics

|

2022

|

Vol. 24, no. 2

163--176

EN

The aim of the study was to demonstrate the possibility of using stock exchange indices to assess the ability to maintain balance as a supplement to analyzes using values determined in the time and frequency domains. Methods: 83 healthy people (56 females, 27 males, age years 21 SD = 1.3 years) participated in the research. Measurements were performed with open and closed eyes and in the virtual environment with two sceneries oscillating at four frequencies. The results determined in the time and frequency domains were analyzed in relation to the results calculated with the use of stock exchange indicators for which the Trend Change Index was formulated. Performed measurements made it possible to determine the average COP speed, the average COP speed and range of movement towards AP, power spectral density PSD and stock exchange indices. Results: In the case of PSD values for the ranges above and below 0.5 Hz, statistically significant differences occurred for most measurements. Obtained values of TCI coefficient were similar and no statistically significant differences were observed. The maximum values of the PSD medians were obtained in trials with the oscillating scenery. Conclusions: Conducted analyzes showed that use of stock exchange indicators broadens the interpretative possibilities of COP measurements by determining the number of consecutive skips (changes in the direction) of the COP and prioritizing according to the times between them. The applied stock market analysis methods also filtered out changes in the position resulting from noises that could not be removed with the use of standard low-pass filters.

3

Influence of the base of support widths on postural control and feet loading symmetry during squat – preliminary study

Kędziorek Justyna, Błażkiewicz Michalina

Acta of Bioengineering and Biomechanics

|

2022

|

Vol. 24, no. 2

55--63

EN

The symmetry of feet loading and adequate postural control are crucial aspects of proper squat performance. The study aimed to evaluate the effect of various stance widths during squat on postural control and symmetry of feet loading. Methods: Thirty healthy individuals participated in this study. Each participant performed one type of squat with a narrow stance (NS), hip stance (HS) and wide stance (WS). Results: A significantly higher value of CoP path length, the velocity of sways and Area95 were obtained for the WS squat compared to NS and HS. In addition, the wide feet setting significantly affected not only the feet loading symmetry but also the strategy (high LyE), the amount of irregularities (high SampEn) and the CoP time-series roughness complexity (high FD). It has been shown that as the base of support grew, the asymmetry index grew. Conclusions: The wide squat is less stable, requiring more complex postural control behavior and more flexibility. Performing this squat significantly shifts the pressure to the dominant limb.

4

Platform posturographic system using polymer sensors

Dziadak Bogdan, Dudnyk Valentyna, Jurczak Marcin, Wiszniewski Przemysław, Wojtas Kamil

Przegląd Elektrotechniczny

|

2021

|

R. 97, nr 6

81--85

EN

The aim of presented research is a system that can monitor human posture. The project is based on scaled platform and polymer ForceSensitive Resistor (FSR) to detect pressure on predetermined points of examined person’s feet and to measure change of Center of Pressure COP. The data is collected by an Arduino UNO and sent to PC via UART for further analysis and results display (stabilogram and histogram of COP) using Python. The system can be used to support the diagnosis of locomotor and balance system.

PL

Celem prezentowanych badań jest system posturograficzny bazujący na sensorach polimerowych. System bazuje na wyskalowanej platformie z rozlokowanymi sensorami rezystancyjnymi FSR. Sensory wykrywają zmianę nacisku w określonych punktach stóp badanej osoby co umożliwia pomiar Center of Pressure COP. Akwizycja danych odbywa się za pomocą Arduino. Wizualizacja wyników którym są stabilogram i histogram trajektorii COP, przedstawiana jest w autorskiej aplikacji napisanej przy użyciu języka Python. System może być wykorzystany do wspomagania diagnostyki układu ruchowego i równowagi.

5

Muscle co-contraction of ankle joint in young adults in functional reach test at different distances

Iwamoto Yoshitaka, Kawakami Wataru, Miyoshi Fumiya, Takeuchi Ryosuke, Takeuchi Yasutaka, Motohiro Yusuke, Wen Lin, Takahashi Makoto

Acta of Bioengineering and Biomechanics

|

2021

|

Vol. 23, no. 2

55--61

EN

Purpose: It has been reported that young people may be able to modulate simultaneous contraction depending on the task. The functional reach test (FRT) is widely used as a method to assess dynamic balance. Although there are several reports on the center of pressure (COP), there are few reports on muscle activity and no studies focus on muscle co-contraction during FRT at different distances. We aimed to clarify how the differences in reach distance affect the activity of the lower limb muscles by measuring COP and muscle activity during FRT at different distances. Methods: Eighteen healthy young adults performed FRT at different distances (maximum, 75%, and 50%) and measured COP and muscle activity of tibialis anterior (TA) and soleus (SOL). Postural control variables were calculated from the COP, and mean muscle activity and muscle co-contraction index (CI) were calculated from muscle activity. Each variable was compared between the reach distance conditions and the correlation between the variable was examined. Results: Most COP variables were significantly higher as the reach distance increased. A significant increase in muscle activity and CI was similarly observed with increasing distance. There was no consistent correlation between COP variables and CI, but there was a positive correlation between TA muscle activity and CI. Conclusions: The results of the present study showed that the young people used task-specific strategies by modulating lower limb muscle contraction and varying the degree of simultaneous muscle contraction during reaching movements at different distances.

6

Gender differences of the improvement in balance control based on the real-time visual feedback system with smart wearable devices

Wang I-Lin, Wang Li-I, Xue Shi-Jie, Hu Rui, Jian Rong-Jiun, Ho Chun-Sheng

Acta of Bioengineering and Biomechanics

|

2021

|

Vol. 23, no. 1

163--171

EN

Purpose: The body maintains stability by integrating inputs from the central nervous system of vision, hearing, proprioception, and multiple senses. With the development of smart wearable devices, smart wearable devices can provide real-time center of pressure position-assisted balance control, which is beneficial to maintain physical balance. Methods: Forty healthy college students (20 male, 20 female) participated in this study, and the posture balance actions of left-leg stance non-visual feedback, left-leg stance visual feedback, right-leg stance non-visual feedback, and right-leg stance visual feedback were performed. Visual feedback provided smart insoles matching Podoon APP on a tablet computer with the COP position displayed by a dot as real-time visual feedback. Results: The experimental results show that the displacement, velocity, radius, and area of the COP decreased significantly in the left-leg stance visual feedback/right-leg stance visual feedback, the test compared the parameters in the left-leg stance non-visual feedback/right-leg stance nonvisual feedback (P < 0.05). Providing visual feedback through intelligent insoles can reduce the movement of the center of mass and maintain physical stability for healthy young people of different genders. In the one leg visual/non-visual in standing, the COP maximum anteroposterior displacement, COP anteroposterior velocity, COP radius, and COP area in women are significantly smaller than in men (P < 0.05). Women have better real-time balance control ability than men with smart insoles. Conclusions: The simple intelligent wearable assisted devices can immediately increase the control ability in static stance of men and women, and women have better real-time balance control ability than men.

7

Nonlinear measures in posturography compared to linear measures based on yoga poses performance

Błażkiewicz MIchalina

Acta of Bioengineering and Biomechanics

|

2020

|

Vol. 22, no. 4

15--21

EN

Yoga is known as a type of exercise that combines physical, mental and spiritual aspects. There has not been much research on the postural control in various yoga poses. The aim of this study was to examine CoP regularity in both yoga instructors and novices during the performance of four yoga poses, and to verify the sensitivity of linear and nonlinear methods for assessing postural stability. Methods: The dynamic characteristics of CoP fluctuations were examined using linear and nonlinear methods on a group of 22 yoga instructors (Y) and 18 age-matched non-practitioners of yoga (NY). The study involved maintaining a balance for 20 seconds while performing four yoga poses. Results: Conventional analysis of CoP trajectories showed that NY and Y exhibited similar control of postural sway, as indicated by similar CoP path-length and area values observed in both groups. These results suggest that the special balance yoga training received by Y may not have an impact on less challenging balance conditions, such as the poses used in this experiment. Interestingly, nonlinear dynamical analysis of CoP showed that Y exhibited less CoP regularity and more complex signal than NY, as evidenced by higher values of sample entropy and fractal dimension. Conclusions: The results shed light on the surplus values of CoP trajectories in the nonlinear dynamical analysis to gain further insight into the mechanisms involved in posture control.

8

Center of plantar pressure during gait in pregnancy-related pelvic girdle pain and the effect of pelvic belts

Bertuit J., Leyh C., Feipel V.

Acta of Bioengineering and Biomechanics

|

2018

|

Vol. 20, no. 3

69--76

EN

Many pregnant women suffer from pelvic girdle pain (PGP) during pregnancy. Etiologies are multifactorial and affect the joint stability of the sacroiliac joint. Pelvic belts could restore stability and reduce pain during gait. The center of pressure (COP) is a reliable parameter to assess gait and balance. The objectives of this study were to analyze the COP during gait in pregnant women with PGP, to evaluate the effect of pelvic belts and to compare two types of belts on COP parameters. Materials and Methods: 46 pregnant women with PGP, 58 healthy pregnant women and 23 non-pregnant women participated in the study. The motor task consisted of three gait trials at different velocities on an electronic walkway. Two pelvic belts for pregnant women were used. An analysis of variance was performed to determine the effects of the progression of the pregnancy, gait speed, presence of pregnancy and occurrence of pain on the COP parameters. Results: Compared to the control group, pregnant women with PGP had a higher stance time, but COP displacement and velocity were lower. The COP parameters varied between pregnant women with and without pelvic girdle pain, the use of a belt during pregnancy decreased the walking velocity. No difference was found according to the type of belt. Conclusions: Differences in COP parameters during gait between pregnant women with or without PGP were minimal. Pelvic girdle pain did not affect the center of pressure. Wearing a belt during pregnancy modified the center of pressure velocity during gait in pregnant women with PGP.

9

Influence of changing frequency and various sceneries on stabilometric parameters and on the effect of adaptation in an immersive 3D virtual environment

Jurkojc J., Wodarski P., Bieniek A., Gzik M., Michnik R.

Acta of Bioengineering and Biomechanics

|

2017

|

Vol. 19, no. 3

129--137

EN

Purpose: The aim of the study was to examine the influence of different types of virtual sceneries and frequencies of movement of visual disturbances on stabilometric values as well as whether individual sceneries and changing frequency can minimize effect of adaptation of tested person to applied disturbances. Methods: There were 23 healthy participants. A person has been standing on a Zebris stabilometric platform. Virtual 3D environment was displayed by means of HMD Oculus Rift system. An open (a meadow) and closed (a room) sceneries were used. The sceneries moved along the sagittal axis and rotated around horizontal axis. The measurement lasted 30 seconds and in the middle of it frequency of translational movement was changed from 0.7 Hz to 1.4 Hz or from 1.4 Hz to 0.7 Hz. Results: The data were reported as medians of COP velocity and ellipse area. Visual disturbances caused the increase of these values in comparison with the tests conducted with open eyes. Results divided into periods (the first and the second 15 seconds) showed that in the first half of the test values were higher compared to the second half. The comparison of values obtained for open and closed scenery showed that higher values were recorded for open scenery. Conclusions: The comparison of both types of sceneries on the basis of COP velocity and ellipse area showed that open scenery had a greater impact on the measured stabilometric values. It was found out as well that people got accustomed to the applied disturbances, but this effect was lower in the open scenery.

10

Effects of Diabetic Neuropathy on Body Sway and Slip Perturbation Detection in Older Population

Kim B. J., Robinson C. J.

International Journal of Occupational Safety and Ergonomics

|

2006

|

Vol. 12, No. 3

241--254

EN

Postural control is a common mechanism to compensate for unexpected displacements of the body. In the older population, a slip or fall due to a failure of postural control is a common cause of morbidity and mortality. The ability of postural control decreases with aging or neuropathy. In this study, 2 groups, diabetics and non-diabetics in the older population, were compared to determine how patterns of postural sway during quiet standing were related to the detection of perturbation. The SLIP-FALLS system was applied to the measurement of sway and detection of perturbation. In phase 1 of the development of the predictive model, neural network algorithms were applied to find determinant variables for perturbation detection. In phase 2, a fuzzy logic inference system was developed to investigate the relationship between sway and perturbation detection. Results of this study may be applied to the design of floor mats or shoe insoles for preventing fatigue in workplaces.