scholarly journals Improving postural stability among people with lower-limb amputations by tactile sensory substitution

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Lijun Chen ◽  
Yanggang Feng ◽  
Baojun Chen ◽  
Qining Wang ◽  
Kunlin Wei
Keyword(s):  
Postural Control ◽  
Lower Limb ◽  
Postural Stability ◽  
Pressure Sensors ◽  
Interaction Force ◽  
The Body ◽  
Sensory Substitution ◽  
Foot Pressure ◽  
Vibration Intensity ◽  
Visual Disturbances

Abstract Background For people with lower-limb amputations, wearing a prosthetic limb helps restore their motor abilities for daily activities. However, the prosthesis's potential benefits are hindered by limited somatosensory feedback from the affected limb and its prosthesis. Previous studies have examined various sensory substitution systems to alleviate this problem; the prominent approach is to convert foot–ground interaction to tactile stimulations. However, positive outcomes for improving their postural stability are still rare. We hypothesized that the sensory substiution system based on surrogated tactile stimulus is capable of improving the standing stability among people with lower-limb amputations. Methods We designed a wearable device consisting of four pressure sensors and two vibrators and tested it among people with unilateral transtibial amputations (n = 7) and non-disabled participants (n = 8). The real-time measurements of foot pressure were fused into a single representation of foot–ground interaction force, which was encoded by varying vibration intensity of the two vibrators attached to the participants’ forearm. The vibration intensity followed a logarithmic function of the force representation, in keeping with principles of tactile psychophysics. The participants were tested with a classical postural stability task in which visual disturbances perturbed their quiet standing. Results With a brief familiarization of the system, the participants exhibited better postural stability against visual disturbances when switching on sensory substitution than without. The body sway was substantially reduced, as shown in head movements and excursions of the center of pressure. The improvement was present for both groups of participants and was particularly pronounced in more challenging conditions with larger visual disturbances. Conclusions Substituting otherwise missing foot pressure feedback with vibrotactile signals can improve postural stability for people with lower-limb amputations. The design of the mapping between the foot–ground interaction force and the tactile signals is essential for the user to utilize the surrogated tactile signals for postural control, especially for situations that their postural control is challenged.

scholarly journals Improving Postural Stability among Amputees by Tactile Sensory Substitution

2021 ◽  
Author(s):  
Lijun Chen ◽  
Yanggang Feng ◽  
Baojun Chen ◽  
Qining Wang ◽  
Kunlin Wei
Keyword(s):  
Postural Control ◽  
Real Time ◽  
Lower Limb ◽  
Postural Stability ◽  
Interaction Force ◽  
Sensory Substitution ◽  
Foot Pressure ◽  
Vibration Intensity ◽  
Lower Limb Amputees ◽  
Visual Disturbances

Abstract BackgroundFor lower-limb amputees, wearing a prosthetic limb helps restore their motor abilities for daily activities. However, the prosthesis's potential benefits are hindered by limited somatosensory feedback from the affected limb and its prosthesis. Previous studies have examined various sensory substitution systems to alleviate this problem; the prominent approach is to convert foot-ground interaction to tactile stimulations. However, positive outcomes for improving amputees' postural stability are still rare. We hypothesize that the intuitive design of tactile signals based on psychophysics shall enhance the feasibility and utility of real-time sensory substitution for lower-limb amputees. MethodsWe designed a wearable device consisting of four pressure sensors and two vibrators and tested it among the unilateral transtibial amputees (n=7) and the able-bodied (n=8). The real-time measurements of foot pressure were fused into a single representation of foot-ground interaction force, which was encoded by varying vibration intensity of the two vibrators attached to the participants’ forearm. The layout of vibrators was spatially congruent with the foot force sensors' placement; the vibration intensity followed a logarithmic function of the force representation, in keeping with principles of tactile psychophysics. The participants were tested with a classical postural stability task in which visual disturbances perturbed their quiet standing. ResultsWith a brief familiarization of the system, the participants exhibited better posture stability against visual disturbances when switching on sensory substitution than without. The body sway was substantially reduced, as shown in head movements and excursions of the center of pressure. The improvement was present for both amputees and able-bodied controls and was particularly pronounced in more challenging conditions with larger visual disturbances. ConclusionsSubstituting otherwise-missing foot pressure feedback with vibrotactile signals can improve postural stability for lower-limb amputees. The intuitive design of the mapping between the foot-ground interaction force and the tactile signals is essential for the user to utilize the surrogated tactile signals for postural control, especially for situations that their postural control is challenged.

scholarly journals Design of wireless device to measure plantar pressure and gait analysis

2019 ◽  
Vol 2 (1) ◽  
pp. 174-181
Author(s):  
Mahendra Khatri ◽  
Sambardhan Dabadi ◽  
Sandeep Kumar Shrestha ◽  
Saugat Acharya ◽  
Sudip Tamang ◽  
...  
Keyword(s):  
Hip Joint ◽  
Lower Limb ◽  
Plantar Pressure ◽  
Walking Speed ◽  
Pressure Sensors ◽  
The Body ◽  
Joint Movement ◽  
Significant Difference ◽  
Mean Pressure ◽  
The Mean

Foot plantar pressure is the pressure field that acts between the plantar region of the foot and supporting ground. The pressure exerted on the variable region of the foot can be determined using discrete pressure sensors. Information obtained from these sensors is useful in the measurement of gait and posture for diagnosing various problems associated with a lower limb, footwear design, and sports biomechanics. This project is aimed to design a portable in-shoe plantar pressure and gyroscope-based gait angle measurement system. Six Force Sensitive Resistor (FSR) placed in the sole (hallux, 1st, 5th metatarsal, midfoot lateral, midfoot medial and heel respectively) detects the plantar pressure and gyroscope placed at the ankle, knee and hip help measure the orientation and angle of joint movement during various phases of gait. The study among 16 male and 16 female subjects illustrated the significant pressure variation (p<0.0001, t=5.17 with α=95%). Similarly, there was a significant difference in pressure between normal and fast walking speed (p<0.0001, t=5.88) with mean values of 353Kpa and 426Kpa respectively. The mean pressure value for slow walking speed was 423Kpa while there was no significant variation between slow and normal walking speeds (p=0.62, t=1.98). Plantar pressure increased linearly with an increase in the body weight of a person as well. The mean pressure for the 45-50 age group was 313.25Kpa and that for 70-75 was 449Kpa. The study among 10 diabetics and 10 non-diabetic subjects illustrated significantly higher pressure on 1st and 5th metatarsal on diabetic subjects (p=0.0207 and t=2.536). The movement of ankle, knee and hip joint is visualized using the 3D model of a lower limb through processing software. The study illustrated the range of ankle joint movement between -60(dorsiflexion) to 200(plantarflexion), for knee joint was 00 to 300 (flexion) and that for hip joint was -50(extension) to 400(flexion). There was a significant difference in angular values for all three joints while climbing up and down the staircase as compared to walk in a level surface.

scholarly journals The effect of support surface and footwear condition on postural sway and lower limb muscle action of the old people

2019 ◽  
Author(s):  
Meizhen Huang ◽  
Kit-lun Yick ◽  
Sun-pui Ng ◽  
Joanne Yip ◽  
Roy Cheung
Keyword(s):  
Lower Limb ◽  
Postural Stability ◽  
Muscle Activation ◽  
Postural Sway ◽  
The Elderly ◽  
The Body ◽  
Support Surface ◽  
Lower Limb Muscle ◽  
Limb Muscle ◽  
Age Related

Abstract Background: Diminished somatosensory function and lower plantar cutaneous sensitivity have been identified as a critical age-related change, which is related to postural instability in the older population. Footwear is suggested that can modulate the postural stability by altering the interface between the foot sole and the ground. However, it is unclear whether this footwear effect could also influence lower limb muscle activation for the elderly. This study aimed to investigate the footwear insole texture and supporting surface condition on static postural stability and lower limb muscle activation for healthy older people. Methods: This is a single-session study with repeated measurements. Twenty-three healthy older female stood on the firm (i.e., concrete floor) and foam surfaces with their eyes open in the three footwear conditions, namely barefoot, plain shoes and nodulous insole shoes, for 30 seconds. Static postural sway and muscle activation of biceps femoris (BF), vastus lateralis (VL), tibialis anterior (TA), and lateral gastrocnemius (LG) of the dominant leg were measured during each testing condition. Results: compared to firm surface, standing on the foam could significantly increase the body sway and lower limb muscle activation (p<0.05); compared to barefoot, when standing on the foam, wearing footwear significantly decreased the VL and TA muscle activation and minimize the postural sway in ML and AP direction, while the influence is larger for the nodulous shoes compared to the plain shoes. A positive correlation was observed between the lower limb muscle activation and AP (r=0.327-0.389, p<0.001) and total sway path length (r=0.317-0.427, p<0.001). Conclusions: footwear could improve the postural stability and decease the fall risk comparing to barefoot when the somatosensory input is in disturbance, while the improvement is larger when wearing nodulous insole footwear for the elderly.

Control of sway using vibrotactile feedback of body tilt in patients with moderate and severe postural control deficits

2005 ◽  
Vol 15 (5-6) ◽  
pp. 313-325
Author(s):  
C. Wall ◽  
E. Kentala
Keyword(s):  
Postural Control ◽  
Postural Stability ◽  
Body Motion ◽  
Body Tilt ◽  
Joint Movement ◽  
Foot Pressure ◽  
Eyes Closed ◽  
The Subject ◽  
Anterior Posterior ◽  
Vibrotactile Display

We evaluated the effect of the vibrotactile display of body tilt upon the postural stability of vestibulopathic subjects during standing. Two groups were studied: those with moderate and with severe deficits as defined by postural stability test scores. They were studied under conditions of distorted sensory input, and during anterior-posterior perturbations. Seventeen subjects, with uni- or bilateral vestibular deficits, as determined by electronystagmography and vertical axis rotation, were tested using Equitest® computerized dynamic posturography (CDP). Based on their performance on the CDP they were divided into two groups having either moderate (nine subjects) or severe (eight subjects) postural control deficits. Their anterior-posterior (A/P) body motion at the waist was measured with a micromechanical rate gyroscope and a linear accelerometer. The resulting tilt estimate was displayed by a vibrotactile array attached to the torso. The vibration served as a tilt feedback to the subject. The subject's performance was evaluated using the root-mean-square (RMS) of both the A/P body motion and center-of-pressure (CoP) estimates. Sensory distortions were introduced using the Equitest® Sensory Organization Tests (SOT). These tests are designed to distort A/P sensory inputs while standing. The SOT 5 distorts proprioceptive information about ankle joint movement, while the subject stands eyes-closed on a moving support platform that measures foot pressure. The SOT 6 adds distorted visual information about body movement instead of testing with eyes closed. Perturbations were introduced using the Equitest® Motor Control Tests (MCT). These move the support platform forward or backward with small, medium and large displacements in the horizontal plane while measuring subjects' foot pressure responses. We used the medium and large backward tests. Vibrotactile display of body tilt reduced the subjects' A/P sway and improved their balance. The finding was more evident for those subjects with severe deficits than those moderate ones. This trend was found for both SOT 5 and 6, as well as the medium and large MCT. Additionally, during the MCT, the peak deflection and mean recovery time also decreased significantly.

AGE-RELATED CHANGES IN POSTURAL RE-BALANCED ABILITY DURING A CONTINUOUS AND UNEXPECTED PERTURBATION INTEGRATED WITH VIRTUAL REALITY SCENES

2016 ◽  
Vol 28 (03) ◽  
pp. 1650020
Author(s):  
Chun-Ju Chang ◽  
Jen-Suh Chern ◽  
Tsui-Fen Yang ◽  
Sai-Wei Yang
Keyword(s):  
Virtual Reality ◽  
Postural Control ◽  
Postural Stability ◽  
Center Of Pressure ◽  
Random Sequence ◽  
Weight Bearing ◽  
The Body ◽  
Assessment Protocol ◽  
Healthy Elderly ◽  
Age Related

The degeneration of sensory and motor systems due to aging could affect the elderly’s posture and increase the risk of falling. The strategies applied to maintain postural stability might be different between ages, especially in the condition requiring both proprioception and vision sensorimotor coupling. This study proposed a novel sensorimotor assessment protocol to evaluate the postural control ability across the aging process, by using the computerized dynamic posturography and the virtual reality (VR) system. Ten young and 20 elderly healthy adults without fall experience were recruited, and were assessed on a continuous-perturbed platform with or without the VR-based visual interference in a random sequence. Measured variables of the center of pressure as well as the weight-bearing ratio were analyzed and compared. Results showed that the postural sway was significantly larger in all subjects under the VR condition, but the young subjects could rapidly adjust the body to regain postural stability in a rhythmic and symmetric manner; whereas, the elderly adults performed less effectively in postural response. We suggested that the application of the multiple sensation disturbances with VR could effectively evaluate the postural control ability among the healthy elderly. The proposed assessing protocol is also recommended for training the sensorimotor integration to improve the dynamic postural control ability.

scholarly journals Effect of Balance Training on Postural Analysis of Patients suffering from Balance Disorders: A Preliminary Report

2017 ◽  
Vol 51 (4) ◽  
pp. 170-174
Author(s):  
Swapnil Bari ◽  
Kashif Sherwani ◽  
Neelesh Kumar
Keyword(s):  
Postural Stability ◽  
Preliminary Report ◽  
Balance Training ◽  
The Body ◽  
Centre Of Pressure ◽  
Foot Pressure ◽  
Balance Disorders ◽  
Quantitative Score ◽  
Postural Analysis ◽  
Postural Performance

ABSTRACT Introduction Postural stability assessment is an important task that has found widespread medical and therapeutic applications. Typically, balance measurement systems are used for this purpose. The quantitative score of postural balance is very important in determining improvement of the patients suffering from balance disorder. Postural stability of humans is highly dependent on the position of centre of pressure of the body. The analysis of sway of a human body can be successfully done by studying oscillations of its centre of pressure. The distribution of foot pressure over different regions namely medial—lateral and anterior— posterior, governs the balance of the posture in both directions. Objective The aim of this study is to assess quantitative changes in the postural stability of patients suffering from balance disorders after providing them biofeedback based balance training. Materials and methods We used Force Sensing Resistors (FSRs) to sense the magnitude of forces acting at various points of both the feet. The centre of pressure is determined using the positions of various force points and magnitude of the force acting on them. The higher capability of the body to remain at that position implies higher postural stability and a lower power of sway. The force sensors produce signal proportional to the magnitude of the foot pressure. This signal after being collected by the Data Acquisition Board is fed to the system for calculating the centre of pressure and drawing a real time graph. Different algorithms are used to determine its mean position and compare the stability. The repeated analysis shows the amount of change in patient's postural behaviour, before and after the training. Results Until the publication of this research work, analysis of the data of 4 patients was performed. Post intervention trials resulted in higher scores of their postural performance. Hence, favourable results were obtained showing improvement in postural stability of the patients. Conclusion Wider variety of ataxia patients can be chosen to perform this assessment. The system is capable of determining a quantitative score of improvement of the postural stability and thus can be used to assess the postural performance of patients suffering from different postural disorders. How to cite this article Bari S, Saxena S, Sherwani K, Kumar N, Dhillon MS. Effect of Balance Training on Postural Analysis of Patients suffering from Balance Disorders: A Preliminary Report. J Postgrad Med Edu Res 2017;51(4):170-174.

scholarly journals Prevalence of floating toe and its relationship with static postural stability in children: The Yamanashi adjunct study of the Japan Environment and Children’s Study (JECS-Y)

2021 ◽  
Author(s):  
Taro Fujimaki ◽  
Masanori Wako ◽  
Kensuke Koyama ◽  
Naoto Furuya ◽  
Ryoji Shinohara ◽  
...  
Keyword(s):  
Postural Stability ◽  
Center Of Pressure ◽  
The Body ◽  
Ground Contact ◽  
Foot Pressure ◽  
Eyes Closed ◽  
Stability Measurement ◽  
Eyes Open ◽  
The Relationship ◽  
Very High

AbstractFloating toe (FT) is a frequently seen condition in which a toe is inadequately in contact with the ground. Although toes play an important role in stabilizing standing posture and walking, many aspects of the effects of FT on the body remain unclear. To our knowledge, there have been no reports about the relationship between FT and postural stability, especially in children. This study aimed to clarify the prevalence of FT and its relationship with static postural stability in children. Of the 400 children aged 8 years who participated in our cohort study, 396, who were examined for static postural stability, were included in this study. Postural stability and FT were assessed using a foot pressure plate. The sway path length of the center of pressure and the area of the ellipse defined as the size of the area marked by the center of pressure were measured as an evaluation of static postural stability. We calculated the “floating toe score (FT score: small FT score indicates insufficient ground contact of the toes)” using the image of the plantar footprint obtained at the postural stability measurement. The FT rate was very high at more than 90%, and the FT score in the eyes-closed condition was significantly higher than that in the eyes-open condition in both sexes. The FT score significantly correlated with the center of pressure path and area. Our results suggest that ground contact of the toes is not directly related to static postural stability in children, but it may function to stabilize the body when the condition becomes unstable, such as when the eyes are closed.

Monopodal Postural Stability Assessment by Wireless Inertial Measurement Units Through the Fast Fourier Transform

2020 ◽  
Vol 29 (6) ◽  
pp. 738-747
Author(s):  
José Pino-Ortega ◽  
Alejandro Hernández-Belmonte ◽  
Carlos D. Gómez-Carmona ◽  
Alejandro Bastida-Castillo ◽  
Javier García-Rubio ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Lumbar Spine ◽  
Fast Fourier Transform ◽  
Lower Limb ◽  
Postural Stability ◽  
National Level ◽  
The Body ◽  
Stability Assessment ◽  
Body Segment ◽  
Body Segments

Objectives: (1) To describe the fast Fourier transform (FFT) multijoint as monopodal postural stability measurement in well-trained athletes, (2) to compare the within-subject FFT between laterality, joints, and body segments, and (3) to establish the within- and between-subject relationship between joints. Methods: Twelve national-level basketball players participated voluntarily in this investigation. The participants performed two 60-second repetitions of a monopodal stability test (1 repetition with each lower limb), separated by 3 minutes of active recovery. All tests were recorded by 4 WIMU PRO™ inertial devices located on the ankle, knee, lumbar spine, and thoracic spine. The main variable was total acceleration, where the FFT was applied. Results: The higher instability results were found in the ankle and in the nondominant lower limb (dominant = 1.131 [0.122] a.u. (arbitrary units); nondominant = 1.141 [0.172] a.u). In the body segment analysis, the greater percentage of differences (%diff) were shown between lumbar spine and knee in the dominant (%diff = −2.989%; d = 0.87) and nondominant (%diff = −3.243%; d = 0.90) lower limb. Finally, very large between-subjects variability was found in all joints and body segments. Conclusions: The described protocol is proposed for monopodal postural stability assessment, being useful to provide information about the stability of joints and the body segment between joints. Besides, a within-subject analysis is recommended, and the FFT calculation will enable a linear analysis of each test.

scholarly journals Prevalence of floating toe and its relationship with static postural stability in children: The Yamanashi adjunct study of the Japan Environment and Children’s Study (JECS-Y)

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0246010
Author(s):  
Taro Fujimaki ◽  
Masanori Wako ◽  
Kensuke Koyama ◽  
Naoto Furuya ◽  
Ryoji Shinohara ◽  
...  
Keyword(s):  
Postural Stability ◽  
Center Of Pressure ◽  
The Body ◽  
Ground Contact ◽  
Standing Posture ◽  
Foot Pressure ◽  
Eyes Closed ◽  
Stability Measurement ◽  
Eyes Open ◽  
The Relationship

Floating toe (FT) is a frequently seen condition in which a toe is inadequately in contact with the ground. Although toes play an important role in stabilizing standing posture and walking, many aspects of the effects of FT on the body remain unclear. To our knowledge, there have been no reports about the relationship between FT and postural stability, especially in children. This study aimed to clarify the prevalence of FT and its relationship with static postural stability in children. Of the 400 children aged 8 years who participated in our cohort study, 396, who were examined for static postural stability, were included in this study. Postural stability and FT were assessed using a foot pressure plate. The sway path length of the center of pressure and the area of the ellipse defined as the size of the area marked by the center of pressure, were measured as an evaluation of static postural stability. We calculated the “floating toe score (FT score: small FT score indicates insufficient ground contact of the toes)” using the image of the plantar footprint obtained at the postural stability measurement. The rate of FT was elevated at more than 90%, and the FT score in the eyes-closed condition was significantly higher than that in the eyes-open condition in both sexes. The FT score significantly correlated with the center of pressure path and area. Our results suggest that ground contact of the toes is not directly related to static postural stability in children, but it may function to stabilize the body when the condition becomes unstable, such as when the eyes are closed.

scholarly journals The Effect of a Lower-Limb Sensory Prosthesis on Balance and Gait in People With Peripheral Neuropathy

2017 ◽  
Author(s):  
Sara R. Koehler-McNicholas ◽  
Lori Danzl ◽  
Lars Oddsson
Keyword(s):  
Peripheral Neuropathy ◽  
Lower Limb ◽  
Balance Control ◽  
Cost Effective ◽  
Epidemiological Studies ◽  
Lower Limbs ◽  
Sensory Substitution ◽  
Foot Pressure ◽  
Increased Risk ◽  
Foot Pad

Peripheral neuropathy (PN), commonly caused by diabetes mellitus, is a debilitating condition that currently affects approximately 20 million Americans. Chronic symptoms of PN often involve pain and weakness of the lower limbs, with eventual sensation loss on the plantar surfaces of the feet. According to epidemiological studies, reduced foot sole sensation has been linked to decreased standing stability [1] and an increased risk of falling [2]. Consequently, cost-effective interventions are needed to improve balance and mobility in this population. A growing body of research suggests that vibrotactile cues delivered to sensate areas of the lower limb may be an effective way to provide information about foot sole pressure to PN patients who experience poor balance control. Indeed, sensory substitution devices that provide vibrotactile feedback have been shown to aid in balance and improve postural control in various patient populations [3–7]. However, none of these technologies have been based on measurements of foot pressure nor have they been used as a balance prosthesis. The goal of this study was to investigate the effect of a new external lower-limb sensory prosthesis, the Walkasins™, on the balance and gait of individuals with PN who experience balance problems [8]. Walkasins™ consist of two parts: a leg unit and a foot pad (Figure 1). The leg unit wraps around the lower leg of the user and contains electronics for reading foot pad pressure signals, a microprocessor, and four vibrating motors that provide gentle tactile sensory cues to the front, back, medial, and lateral surfaces of the user’s leg. These cues reflect real-time foot pressure information at a location above the ankle where skin sensation is still present. The leg unit has a power button, two status LEDs, and a reset button (not shown in Figure 1). Power is supplied by a rechargeable internal battery. The foot pad is a thin consumable sole insert that can be cut to size and fit into a regular shoe. The foot pad connects to the leg unit through a physical cable. In this study, subjects performed gait and balance assessments with and without the Walkasins™ turned on in order to determine its short-term effects.

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