scholarly journals Experimental Implementation of Automatic Control of Posture-Dependent Stimulation in an Implanted Standing Neuroprosthesis

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Brooke M. Odle ◽  
Lisa M. Lombardo ◽  
Musa L. Audu ◽  
Ronald J. Triolo
Keyword(s):  
Center Of Pressure ◽  
Quiet Standing ◽  
Average Width ◽  
Sensory Disorders ◽  
Straight Line ◽  
Experimental Implementation ◽  
Cord Injury ◽  
The Mean ◽  
Ellipse Area ◽  
Nominal Position

Knowledge of the upper extremity (UE) effort exerted under real-world conditions is important for understanding how persons with motor or sensory disorders perform the postural shifts necessary to complete many activities of daily living while standing. To this end, a feedback controller, named the “Posture Follower Controller”, was developed to aid in task-dependent posture shifting by individuals with spinal cord injury standing with functional neuromuscular stimulation. In this experimental feasibility study, the controller modulated activation to the paralyzed lower extremity muscles as a function of the position of overall center of pressure (CoP), which was prescribed to move in a straight line in forward and diagonal directions. Posture-dependent control of stimulation enabled leaning movements that translated the CoP up to 48 mm away from the nominal position during quiet standing. The mean 95% prediction ellipse area, a measure of the CoP dispersion in the forward, forward-right, and forward-left directions, was 951.0±341.1 mm2, 1095.9±251.2 mm2, and 1364.5±688.2 mm2, respectively. The average width of the prediction ellipses across the three directions was 15.1 mm, indicating that the CoP deviated from the prescribed path as task-dependent postures were assumed. The average maximal UE effort required to adjust posture across all leaning directions was 24.1% body weight, which is only slightly more than twice of what is required to maintain balance in an erect standing posture. These preliminary findings suggest that stimulation can be modulated to effectively assume user-specified, task-dependent leaning postures characterized by the CoP shifts that deviate away from the nominal position and which require moderate UE effort to execute.

The Effects of Uni- and Bilateral Fatigue on Postural and Power Tasks

2013 ◽  
Vol 29 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Paulo H. Marchetti ◽  
Maria I.V. Orselli ◽  
Marcos Duarte
Keyword(s):  
Lower Limb ◽  
Healthy Subjects ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Lower Limbs ◽  
Quiet Standing ◽  
Ground Reaction Forces ◽  
Before And After ◽  
Reaction Forces ◽  
The Mean

The aim of this study was to investigate the effects of unilateral and bilateral fatigue on both postural and power bipedal tasks. Ten healthy subjects performed two tasks: bipedal quiet standing and a maximal bipedal counter-movement jumping before and after unilateral (with either the dominant or nondominant lower limb) and bilateral (with both lower limbs) fatigue. We employed two force plates (one under each lower limb) to measure the ground reaction forces and center of pressure produced by subjects during the tasks. To quantify the postural sway during quiet standing, we calculated the resultant center of pressure (COP) speed and COP area of sway, as well as the mean weight distribution between lower limbs. To quantify the performance during the countermovement jumping, we calculated the jump height and the peak force of each lower limb. We observed that both unilateral and bilateral fatigue affected the performance of maximal voluntary jumping and standing tasks and that the effects of unilateral and bilateral fatigue were stronger in the dominant limb than in the nondominant limb during bipedal tasks. We conclude that unilateral neuromuscular fatigue affects both postural and power tasks negatively.

scholarly journals KINETIC AND KINEMATIC ANALYSIS OF STANCE WITH AND WITHOUT ARM SUPPORT IN INCOMPLETE SPINAL CORD INJURED SUBJECTS

2010 ◽  
Vol 22 (06) ◽  
pp. 465-474
Author(s):  
Elin Allen Yu ◽  
Pei-Pei Hsu ◽  
Tung-Wu Lu ◽  
Wen-Ling Yeh ◽  
Kwan-Hwa Lin
Keyword(s):  
Spinal Cord ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Control Strategies ◽  
Force Plate ◽  
Trunk Muscles ◽  
Quiet Standing ◽  
Joint Angles ◽  
Cord Injury ◽  
Arm Support

There is a lack of studies concerning standing stability in subjects with incomplete spinal cord injury (SCI). The aims of this study were to analyze the changes of center of pressure (COP), joint moment, joint angle, and muscle activities in patients with incomplete SCI during quiet stance with and without arm support. Ten cervical–thoracic cord incompletely injured patients (mean age: 47.8 ± 13.4 years old) participated in this study. They performed quiet standing with each leg on separate force plate (AMTI, USA) for 5 s with and without holding the walker to obtain the kinetic data. The kinematic data of joint angles were recorded by Motion Analysis System (Vicon 250, Oxford, UK). The electromyographic activities of trunk muscles and quadriceps were recorded by surface electrodes. The results indicated that the COP sway area and the normalized COP sway area significantly (P < 0.01) increased from 94.9 ± 61.3 mm2 to 254.6 ± 91.8 mm2 and from 0.0013 ± 0.0007 to 0.0037 ± 0.0012, respectively, in patients with incomplete SCI, while standing with arms released from walker. The ankle and knee moments also increased significantly (P < 0.05) during stance without support. However, the joint angles and recorded muscle activities were not significantly different between those with and without support. The conclusion was that the proprioceptive feedback of postural sway, and the motor control strategies of knee–ankle muscles would be important for patients with incomplete SCI during stance without arm support.

Inter-joint coordination between the ankle and hip joints during quiet standing in individuals with motor incomplete spinal cord injury

2021 ◽  
Author(s):  
Jae W Lee ◽  
Katherine Chan ◽  
Janelle Unger ◽  
Jaeeun Yoo ◽  
Kristin E Musselman ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Hip Joint ◽  
Spinal Cord Injuries ◽  
Postural Sway ◽  
Center Of Pressure ◽  
Uncontrolled Manifold ◽  
Quiet Standing ◽  
Hip Joints ◽  
Joint Coordination ◽  
Cord Injury

Individuals with motor incomplete spinal cord injuries (iSCI) often have impaired abilities to maintain upright balance. For able-bodied (AB) individuals, the ankle and hip joint accelerations are in anti-phase to minimize the postural sway during quiet standing. Here we investigated how inter-joint coordination between the ankle and hip joints was affected in individuals with iSCI leading to their larger postural sway during quiet standing. Data from sixteen individuals with iSCI, fourteen age- and sex-matched AB individuals and thirteen young AB individuals were analyzed. The participants performed quiet standing during which kinematic and kinetic data were recorded. Postural sway was quantified using center-of-pressure velocity and center-of-mass acceleration. Individual ankle and hip joint kinematics were quantified, and the inter-joint coordination was assessed using the cancellation index (CI), goal-equivalent variance (GEV), non-goal-equivalent variance (NGEV) and uncontrolled manifold (UCM) ratio. Individuals with iSCI displayed greater postural sway compared to AB individuals. The contribution of ankle angular acceleration towards one's sway was significantly greater for those with iSCI compared to AB groups. CI and the UCM ratio were not statistically different between the groups, while GEV and NGEV were significantly greater for the iSCI group compared to the AB groups. We demonstrated that individuals with iSCI show larger postural sway compared to the AB individuals during quiet standing, primarily due to larger ankle joint acceleration. We also demonstrated that the inter-joint coordination between ankle and hip joint is not affected in individuals with iSCI, which is not successfully able to reduce the large COM acceleration.

scholarly journals Electrical stimulator with mechanomyography-based real-time monitoring, muscle fatigue detection, and safety shut-off: a pilot study

2020 ◽  
Vol 65 (4) ◽  
pp. 461-468
Author(s):  
Jannatul Naeem ◽  
Nur Azah Hamzaid ◽  
Amelia Wong Azman ◽  
Manfred Bijak
Keyword(s):  
Muscle Fatigue ◽  
Real Time ◽  
Isometric Force ◽  
Mean Square ◽  
Clear Indication ◽  
Initial Value ◽  
Cord Injury ◽  
The Mean ◽  
Electrical Stimulator ◽  
Fatigue Detection

AbstractFunctional electrical stimulation (FES) has been used to produce force-related activities on the paralyzed muscle among spinal cord injury (SCI) individuals. Early muscle fatigue is an issue in all FES applications. If not properly monitored, overstimulation can occur, which can lead to muscle damage. A real-time mechanomyography (MMG)-based FES system was implemented on the quadriceps muscles of three individuals with SCI to generate an isometric force on both legs. Three threshold drop levels of MMG-root mean square (MMG-RMS) feature (thr50, thr60, and thr70; representing 50%, 60%, and 70% drop from initial MMG-RMS values, respectively) were used to terminate the stimulation session. The mean stimulation time increased when the MMG-RMS drop threshold increased (thr50: 22.7 s, thr60: 25.7 s, and thr70: 27.3 s), indicating longer sessions when lower performance drop was allowed. Moreover, at thr70, the torque dropped below 50% from the initial value in 14 trials, more than at thr50 and thr60. This is a clear indication of muscle fatigue detection using the MMG-RMS value. The stimulation time at thr70 was significantly longer (p = 0.013) than that at thr50. The results demonstrated that a real-time MMG-based FES monitoring system has the potential to prevent the onset of critical muscle fatigue in individuals with SCI in prolonged FES sessions.

scholarly journals Weighted statistical binary patterns for facial feature representation

2021 ◽  
Author(s):  
Hung Phuoc Truong ◽  
Thanh Phuong Nguyen ◽  
Yong-Guk Kim
Keyword(s):  
Comprehensive Evaluation ◽  
Facial Feature ◽  
Input Image ◽  
Feature Representation ◽  
Illumination Variation ◽  
Straight Line ◽  
Mean And Variance ◽  
The Mean ◽  
Face Datasets ◽  
Degraded Images

AbstractWe present a novel framework for efficient and robust facial feature representation based upon Local Binary Pattern (LBP), called Weighted Statistical Binary Pattern, wherein the descriptors utilize the straight-line topology along with different directions. The input image is initially divided into mean and variance moments. A new variance moment, which contains distinctive facial features, is prepared by extracting root k-th. Then, when Sign and Magnitude components along four different directions using the mean moment are constructed, a weighting approach according to the new variance is applied to each component. Finally, the weighted histograms of Sign and Magnitude components are concatenated to build a novel histogram of Complementary LBP along with different directions. A comprehensive evaluation using six public face datasets suggests that the present framework outperforms the state-of-the-art methods and achieves 98.51% for ORL, 98.72% for YALE, 98.83% for Caltech, 99.52% for AR, 94.78% for FERET, and 99.07% for KDEF in terms of accuracy, respectively. The influence of color spaces and the issue of degraded images are also analyzed with our descriptors. Such a result with theoretical underpinning confirms that our descriptors are robust against noise, illumination variation, diverse facial expressions, and head poses.

Assessing the Ergonomic Benefits of a New Adjustable Forklift Backrest

2020 ◽  
Vol 64 (1) ◽  
pp. 976-980
Author(s):  
Pranav Madhav Kuber ◽  
Ehsan Rashedi
Keyword(s):  
Comparative Study ◽  
Motion Capture ◽  
Center Of Pressure ◽  
Body Movement ◽  
Pressure Change ◽  
Motion Capture System ◽  
Design Features ◽  
Wide Range ◽  
Body Sizes ◽  
The Mean

A new forklift backrest has been developed by incorporating adjustability concepts into the design to facilitate comfort to a wide range of users. We have conducted a comparative study between the new and original backrests to assess the effectiveness of design features. Using the phenomenon of restlessness, discomfort of the user was associated with the amount of body movement, where we have used a motion- capture system and a force platform to quantify the individuals’ movement for a wide range of body sizes. Meanwhile, subjective comfort and design feedback were collected using a questionnaire. Our results showed a reduction in the mean torso movement and the maximum center of pressure change of location by 300 and 6 mm, respectively, for the new design. Taking advantage of adjustability feature, the new backrest design exhibited enhanced comfort for longer durations and reduced magnitude of discomfort for a wide range of participants’ body sizes.

Retroclival Epidural Hematomas

Neurosurgery ◽  
2010 ◽  
Vol 67 (2) ◽  
pp. 404-407 ◽  
Author(s):  
R. Shane Tubbs ◽  
Christoph J. Griessenauer ◽  
Todd Hankinson ◽  
Curtis Rozzelle ◽  
John C. Wellons ◽  
...  
Keyword(s):  
Glasgow Coma Scale ◽  
Scale Score ◽  
Glasgow Coma Scale Score ◽  
Pediatric Patients ◽  
Motor Vehicle ◽  
Coma Scale ◽  
Presenting Symptoms ◽  
Cord Injury ◽  
The Mean

Abstract BACKGROUND Retroclival epidural hematomas (REDHs) are infrequently reported. To our knowledge, only 19 case reports exist in the literature. OBJECTIVE This study was performed to better elucidate this pathology. METHODS We prospectively collected data for all pediatric patients diagnosed with REDH from July 2006 through June 2009. Data included mechanism of injury, Glasgow Coma Scale score, neurological examination, treatment modality, and outcome. Magnetic resonance imaging was used to measure REDH dimensions. RESULTS Eight children were diagnosed with REDH, and the hematomas were secondary to motor vehicle–related trauma in all cases. The mean age of patients was 12 years (range 4–17 years). The mean REDH height (craniocaudal) was 4.0 cm, and the mean thickness (dorsoventral) was 1.0 cm. At presentation, the mean Glasgow Coma Scale score was 8 (range 3–14), and there was no correlation between hematoma size and presenting symptoms. Two patients died soon after injury, and 2 additional patients had atlanto-occipital dislocation that required surgical intervention. No patient underwent surgical evacuation of the REDH. The mean follow-up was 14 months. At most recent follow-up, 4 patients are neurologically intact, 1 patient has a complete spinal cord injury, and 1 patient has mild bilateral abducens nerve palsy. CONCLUSION To our knowledge, this study of 8 pediatric patients is the largest series of patients with REDH thus far reported. Based on our study, we found that REDH is likely to be underdiagnosed, atlanto-occipital dislocation should be considered in all cases of REDH, and many patients with REDH will have minimal long-term neurological injury.

Surface height effects on postural control: A hypothesis for a stiffness strategy for stance*

1999 ◽  
Vol 9 (4) ◽  
pp. 277-286 ◽  
Author(s):  
Mark G. Carpenter ◽  
James S. Frank ◽  
Cathy P. Silcher
Keyword(s):  
Postural Control ◽  
Center Of Pressure ◽  
High Surface ◽  
Quiet Standing ◽  
Vestibular Input ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Balance Confidence ◽  
Eyes Closed ◽  
Ankle Stiffness

One possible factor influencing the control of upright stance is the perceived threat to one's personal safety, i.e. balance confidence. We explored this factor by examining the control of stationary stance when standing on an elevated platform under various conditions of reduced visual and vestibular inputs. Twenty-eight adults (14 male and 14 female, mean age = 23.5 years) participated in the experiment. Postural control was examined by recording the amplitude variability (RMS) and mean power frequency (MPF) of center of pressure excursions (COP) over a 2-minute interval while participants stood in a normal stance on a low (0.19 m) and a high (0.81 m) platform with toes positioned either at or away from the edge of the platform. Vision was manipulated through eyes open and eyes closed trials. Vestibular input was reduced by tilting the head into extension [1]. Anterior-posterior RMS and MPF of COP were significantly influenced by an interaction between surface height and vision. When vision was available, a significant decrease in RMS was observed during quiet standing on a high surface compared to a low surface independent of step restriction. When vision was available MPF increased when subjects were raised from a low to a high surface. The mean position of the COP was significantly influenced by an interaction between height and step restriction. Differences in RMS and MPF responses to height manipulation were observed between genders in eyes closed conditions. Vestibular input influenced postural control at both low and high levels with significant increases in RMS when vestibular input was reduced. The reciprocal changes observed in RMS and MPF suggest modifications to postural control through changes in ankle stiffness. Vision appears to play a role in increasing ankle stiffness when balance confidence is compromised.

scholarly journals Subcutaneous granulocyte colony-stimulating factor administration for subacute traumatic spinal cord injuries, report of neurological and functional outcomes: a double-blind randomized controlled clinical trial

2019 ◽  
Vol 30 (1) ◽  
pp. 19-30 ◽  
Author(s):  
Nazi Derakhshanrad ◽  
Hooshang Saberi ◽  
Mir Saeed Yekaninejad ◽  
Mohammad Taghi Joghataei
Keyword(s):  
Clinical Trial ◽  
Spinal Cord ◽  
Placebo Group ◽  
Spinal Cord Injuries ◽  
Functional Improvement ◽  
Granulocyte Colony Stimulating Factor ◽  
Double Blind ◽  
Cord Injury ◽  
The Mean ◽  
Stimulating Factor

OBJECTIVEGranulocyte-colony stimulating factor (G-CSF) is a major cytokine that has already been clinically verified for chronic traumatic spinal cord injuries (TSCIs). In this study, the authors set out to determine the safety and efficacy of G-CSF administration for neurological and functional improvement in subacute, incomplete TSCI.METHODSThis phase II/III, prospective, double-blind, placebo-controlled, parallel randomized clinical trial was performed in 60 eligible patients (30 treatment, 30 placebo). Patients with incomplete subacute TSCIs with American Spinal Injury Association Impairment Scale (AIS) grades B, C, and D were enrolled. Patients were assessed using the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) scale, Spinal Cord Independence Measure (SCIM-III) and International Association of Neurorestoratology Spinal Cord Injury Functional Rating Scale (IANR-SCIFRS), just before intervention and at 1, 3, and 6 months, after 7 daily subcutaneous administrations of 300 μg/day of G-CSF in the treatment group and placebo in the control group.RESULTSAmong 60 participants, 28 patients (93.3%) in the G-CSF group and 26 patients (86.6%) in the placebo group completed the study protocol. After 6 months of follow-up, the AIS grade remained unchanged in the placebo group, while in the G-CSF group 5 patients (45.5%) improved from AIS grade B to C, 5 (45.5%) improved from AIS grade C to grade D, and 1 patient (16.7%) improved from AIS grade D to E. The mean ± SEM change in ISNCSCI motor score in the G-CSF group was 14.9 ± 2.6 points, which was significantly greater than in the placebo group (1.4 ± 0.34 points, p < 0.001). The mean ± SEM light-touch and pinprick sensory scores improved by 8.8 ± 1.9 and 10.7 ± 2.6 points in the G-CSF group, while those in the placebo group improved by 2.5 ± 0.60 and 1.2 ± 0.40 points, (p = 0.005 and 0.002, respectively). Evaluation of functional improvement according to the IANR-SCIFRS instrument revealed significantly more functional improvement in the G-CSF group (10.3 ± 1.3 points than in the placebo group (3.0 ± 0.81 points; p < 0.001). A significant difference was also observed between the 2 groups as measured by the SCIM-III instrument (29.6 ± 4.1 vs 10.3 ± 2.2, p < 0.001).CONCLUSIONSIncomplete subacute TSCI is associated with significant motor, sensory, and functional improvement after administration of G-CSF.Clinical trial registration no.: IRCT201407177441N3 (www.irct.ir)

scholarly journals Maximum Movement and Cumulative Movement (Travel) to Inform our Understanding of Secondary Spinal Cord Injury and its Application to Collar use in Self-extrication

2021 ◽  
Author(s):  
Tim Nutbeam ◽  
Rob Fenwick ◽  
Barbara May ◽  
Willem Stassen ◽  
Jason Smith ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Healthy Volunteers ◽  
Motor Vehicle ◽  
Cervical Collar ◽  
Spinal Movement ◽  
Cord Injury ◽  
Total Movement ◽  
The Mean ◽  
Secondary Spinal Cord Injury

Abstract Background:Motor vehicle collisions remain a common cause of spinal cord injury. Biomechanical studies of spinal movement often lack “real world” context and applicability. Additional data may enhance our understanding of the potential for secondary spinal cord injury. We propose the metric ‘travel’ (total movement) and suggest that our understanding of movement related risk of injury could be improved if travel was routinely reported. We report maximal movement and travel for collar application in vehicle and subsequent self-extrication.Methods:Biomechanical data on application of cervical collar with the volunteer sat in a vehicle were collected using Inertial Measurement Units on 6 healthy volunteers. Maximal movement and travel are reported. These data and a re-analysis of previously published work is used to demonstrate the utility of travel and maximal movement in the context of self-extrication.Results:Data from a total of 60 in-vehicle collar applications across three female and three male volunteers was successfully collected for analysis. The mean age across participants was 50.3 years (range 28–68) and the BMI was 27.7 (range 21.5–34.6). The mean maximal anterior-posterior movement associated with collar application was 2.3mm with a total AP travel of 4.9mm. Travel (total movement) for in-car application of collar and self-extrication was 9.5mm compared to 9.4mm travel for self-extrication without a collar. Conclusion:We have demonstrated the application of ‘travel’ in the context of self-extrication. Total travel is similar across self-extricating healthy volunteers with and without a collar.We suggest that where possible ‘travel’ is collected and reported in future biomechanical studies in this and related areas of research. It remains appropriate to apply a cervical collar to self-extricating casualties when the clinical target is that of movement minimisation.

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