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posterior center of pressure

Elisa Pelosin, Ambra Bisio, Thierry Pozzo, Giovanna Lagravinese, Oscar Crisafulli, Roberta Marchese, Giovanni Abbruzzese, Laura Avanzino
Postural reactions can be influenced by concomitant tasks or different contexts and are modulated by a higher order motor control. Recent studies investigated postural changes determined by motor contagion induced by action observation (chameleon effect) showing that observing a model in postural disequilibrium induces an increase in healthy subjects' body sway. Parkinson's disease (PD) is associated with postural instability and impairments in cognitively controlled balance tasks. However, no studies investigated if viewing postural imbalance might influence postural stability in PD and if patients are able to inhibit a visual postural perturbation...
2018: Frontiers in Neurology
Gaurav Mathur, Narottama Sindhu, Deependra Vikram Singh, Gurpreet Singh Garcha
PURPOSE: To present a unique case of decompression retinochoroidopathy presenting with intraretinal, subretinal and preretinal hemorrhages. METHODS: A 65-year-old hypertensive female presented with diminution of vision in right eye of 1-week duration. She had been a known case of primary open-angle glaucoma and had undergone trabeculectomy with mitomycin C in right eye 1 week back. Her day 1 postoperative intraocular pressure was 6 mmHg. Her left eye had undergone Ahmed glaucoma valve surgery for the same 2 years back...
March 10, 2018: International Ophthalmology
Anat V Lubetzky, Daphna Harel, Eyal Lubetzky
Sample entropy, a measure of time series regularity, has become increasingly popular in postural control research. We are developing a virtual reality assessment of sensory integration for postural control in people with vestibular dysfunction and wished to apply sample entropy as an outcome measure. However, despite the common use of sample entropy to quantify postural sway, we found lack of consistency in the literature regarding center-of-pressure signal manipulations prior to the computation of sample entropy...
2018: PloS One
Haizhen Luo, Xiaoyun Wang, Mengying Fan, Lingyun Deng, Chuyao Jian, Miaoluan Wei, Jie Luo
Visual input could benefit balance control or increase postural sway, and it is far from fully understanding the effect of visual stimuli on postural stability and its underlying mechanism. In this study, the effect of different visual inputs on stability and complexity of postural control was examined by analyzing the mean velocity (MV), SD, and fuzzy approximate entropy (fApEn) of the center of pressure (COP) signal during quiet upright standing. We designed five visual exposure conditions: eyes-closed, eyes-open (EO), and three virtual reality (VR) scenes (VR1-VR3)...
2018: Frontiers in Neurology
Jie Wang, Ergang Du, Jinfei Tang
BACKGROUND: The management of eyes with nanophthalmos is a dilemma for ophthalmologists due to various complications, especial the eye with malignant glaucoma. We report a case of effective treatment for malignant glaucoma in nanophthalmos. CASE PRESENTATION: An 82-year-old man was performed phacoemulsification in the right eye with normal ocular pressure and nanophthalmos. The surgery was uneventful: an intraocular lens (IOL) was placed and centered in the capsular bag...
February 23, 2018: BMC Ophthalmology
Alessandro Mengarelli, Federica Verdini, Stefano Cardarelli, Francesco Di Nardo, Laura Burattini, Sandro Fioretti
Testing balance through squatting exercise is a central part of many rehabilitation programs and sports and plays also an important role in clinical evaluation of residual motor ability. The assessment of center of pressure (CoP) displacement and its parametrization is commonly used to describe and analyze squat movement and the laboratory-grade force plates (FP) are the gold standard for measuring balance performances from a dynamic view-point. However, the Nintendo Wii Balance Board (NWBB) has been recently proposed as an inexpensive and easily available device for measuring ground reaction force and CoP displacement in standing balance tasks...
February 5, 2018: Journal of Biomechanics
Catherine Quatman-Yates, Scott Bonnette, Resmi Gupta, Jason A Hugentobler, Shari L Wade, Tracy A Glauser, Richard F Ittenbach, Mark V Paterno, Michael A Riley
This study aimed to provide insight into the development of postural control abilities in youth. A total of 276 typically developing adolescents (155 males, 121 females) with a mean age of 13.23 years (range of 7.11-18.80) were recruited for participation. Subjects performed two-minute quiet standing trials in bipedal stance on a force plate. Center of pressure (COP) trajectories were quantified using Sample Entropy (SampEn) in the anterior-posterior direction (SampEn-AP), SampEn in the medial-lateral direction (SampEn-ML), and Path Length (PL) measures...
February 10, 2018: Human Movement Science
Kaushik Annam, Allison J Chen, Irene M Lee, Alfred A Paul, Jorge J Rivera, Paul B Greenberg
Introduction: Cataract surgery is the most frequently performed surgery in the Veterans Health Administration (VHA). A well-known complication is a transient but potentially harmful elevation in intraocular pressure (IOP) within the 24-h postoperative period. The purpose of this study is to investigate the risk factors for IOP elevation 1 d after cataract surgery in a cohort of United States (US) veterans. Materials and Methods: The study included 784 patients who underwent cataract surgery between April 2013 and April 2016 at a single Veterans Affairs medical center in Providence, RI...
February 7, 2018: Military Medicine
Massimiliano Pau, Bruno Leban, Giuseppina Pilloni, Micaela Porta, Fabio Cubeddu, Claudio Secci, Veronica Piras, Marco Monticone
OBJECTIVE: The purpose of this study was to assess the influence of trunk rotation (TR) on postural sway and spatial-temporal parameters of gait in children and early adolescents screened at school for the presence of scoliosis. METHODS: Two hundred and fifty-five individuals aged 9-14 (141 boys, 114 girls) underwent trunk rotation (TR) assessment by means of angle of trunk rotation (ATR) measurements performed with Bunnell's scoliometer. Participants with ATR ≥ 5° formed the TR group whose data were compared with those of a control group (CON) composed of individuals with ATR < 5° matched for age and anthropometric features...
January 31, 2018: Gait & Posture
Xinyao Hu, Jun Zhao, Dongsheng Peng, Zhenglong Sun, Xingda Qu
Postural control is a complex skill based on the interaction of dynamic sensorimotor processes, and can be challenging for people with deficits in sensory functions. The foot plantar center of pressure (COP) has often been used for quantitative assessment of postural control. Previously, the foot plantar COP was mainly measured by force plates or complicated and expensive insole-based measurement systems. Although some low-cost instrumented insoles have been developed, their ability to accurately estimate the foot plantar COP trajectory was not robust...
February 1, 2018: Sensors
Yawen Yu, Richard T Lauer, Carole A Tucker, Elizabeth D Thompson, Emily A Keshner
The current study aimed to explore the impact of visual dependence on sensorimotor coupling of postural sway and visual motion in adults and teens with spastic cerebral palsy (CP). We hypothesized that individuals with CP would exhibit greater magnitudes of sway than healthy individuals, and the presence of visual dependence (VD) would produce instability in the direction of visual motion. Participants stood in a virtual environment in which the visual scene remained static or continuously rotated 30 degree/second in pitch-up or pitch-down...
January 17, 2018: Developmental Neurorehabilitation
Sjoerd T Timmermans, Esmee M Reijnierse, Jantsje H Pasma, Marijke C Trappenburg, Gerard J Blauw, Andrea B Maier, Carel G M Meskers
BACKGROUND: Orthostatic hypotension (OH), a blood pressure drop after postural change, is associated with impaired standing balance and falls in older adults. This study aimed to assess the association between blood pressure (BP) and a measure of quality of standing balance, i.e. Center of Pressure (CoP) movement, after postural change from supine to standing position in geriatric outpatients, and to compare CoP movement between patients with and without OH. METHODS: In a random subgroup of 75 consecutive patients who were referred to a geriatric outpatient clinic, intermittent BP measurements were obtained simultaneously with CoP measurements in mediolateral and anterior-posterior direction directly after postural change during 3 min of quiet stance with eyes open on a force plate...
January 15, 2018: BMC Geriatrics
Bing Chen, Yun-Ju Lee, Alexander S Aruin
Postural control is compromised in the presence of body instability. We studied anticipatory and compensatory postural adjustments people use to maintain balance while standing on an unstable surface and performing voluntary arm movements. Nine healthy participants stood on a sliding board (that was either locked and as such motionless or unlocked and as such free to move in the anterior-posterior direction) and performed fast bilateral arms flexion. Arm acceleration, bilateral electromyographic activity (EMG) of the trunk and lower extremity muscles and center of pressure (COP) displacements were recorded and analyzed within the intervals typical for the anticipatory (APAs) and compensatory (CPAs) postural adjustments...
December 28, 2017: Journal of Electromyography and Kinesiology
Seung-Hyun Hyun, Che-Cheong Ryew
The aim of this study is to compare and analyze the components of ground reaction force (GRF) relative to the foothold heights during downward step of 16-t truck. Adult males (n= 10) jumped downward from each 1st, 2nd, 3rd foothold step and driver's seat orderly using hand rail. Sampling rate of force components of 3 axis (medial-lateral [ML] GRF, anterior-posterior [AP] GRF, peak vertical force [PVF]), variables (COPx, COPy, COP area) of center of pressure (COP), loading rate, and stability index (ML, AP, vertical, and dynamic postural stability index [DPSI]) processed from GRF system was cut off at 1,000 Hz...
December 2017: Journal of Exercise Rehabilitation
Dary D Fiorentino
STRUCTURED ABSTRACT Background: Two of the three standardized field sobriety tests that US law enforcement uses at roadside checks have a postural equilibrium component to them. Those tests have been validated to detect impairment caused by blood alcohol concentrations (BACs) of .08 g/dL or above. Many medical and traffic safety associations support a lower limit, and one state, Utah, has passed a law to lower the limit to .05 g/dL. Many studies have examined the effects of alcohol on postural control (of which postural equilibrium is a component), with a consensus emerging that impairment is usually found at BACs greater than ...
January 11, 2018: Traffic Injury Prevention
Yun-Ju Lee, Bing Chen, Jing-Nong Liang, Alexander S Aruin
Voluntary pushing or translation perturbation of the support surface each induces a body perturbation that affects postural control. The objective of the study was to investigate anticipatory (APA) and compensatory (CPA) postural adjustments when pushing an object (that induces self-initiated perturbation) and standing on a sliding board (that induces translational perturbation). Thirteen healthy young participants were instructed to push a handle with both hands while standing on a sliding board that was either free to move in the anterior-posterior direction or stationary...
January 5, 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Yahiko Takeuchi
PURPOSE: The objective of this study was to determine the positional relationship between the center of mass (COM) and the center of pressure (COP) at the time of step landing, and to examine their relationship with the joint moments exerted by the supporting limb, with regard to factors of the successful backward step response. METHODS: The study population comprised 8 community-dwelling elderly people that were observed to take successive multi steps after the landing of a backward stepping...
2018: PloS One
Juliana Teles Tavares, Daniela Aparecida Biasotto-Gonzalez, Nárlon Cássio Boa Sorte Silva, Frank Shiguemitsu Suzuki, Paulo Roberto Garcia Lucareli, Fabiano Politti
BACKGROUND AND PURPOSE: The maintenance of postural control is influenced by the complexity of a given task. Tasks that require greater attention and cognitive involvement increase the risk of falls among older adults. The aim of the present study was to evaluate the adaptation of the postural control system to different levels of task complexity in physically inactive young and older women. METHODS: A cross-sectional study was conducted with adult women classified as physically inactive based on the results of the International Physical Activity Questionnaire...
December 28, 2017: Journal of Geriatric Physical Therapy
Antara Gokhale, Atheel Kimona, Sandeep Kantor, S Prakash, Yogesh Manhas
Introduction: Posterior reversible encephalopathy syndrome (PRES) is characterized by a range of clinico neuro radiological manifestation along with hypertension due to varied etiology. Contrary to its name, a small number of patients have residual neurological deficits. Patients with severe manifestation of PRES may get admitted to the Intensive Care Unit (ICU) due to coma or status epilepticus. Small case series and large multicenter studies have been reported. Materials and Methods: We report a single center series of ten cases admitted to ICU over a 5 year period in a tertiary care centre...
November 2017: Indian Journal of Critical Care Medicine
David C Kingston, Stacey M Acker
In high knee flexion, contact between the posterior thigh and calf is expected to decrease forces on tibiofemoral contact surfaces, therefore, thigh-calf contact needs to be thoroughly characterized to model its effect. This study measured knee angles and intersegmental contact parameters in fifty-eight young healthy participants for six common high flexion postures using motion tracking and a pressure sensor attached to the right thigh. Additionally, we introduced and assessed the reliability of a method for reducing noise in pressure sensor output...
November 28, 2017: Journal of Biomechanics
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