Abstract:
:Postural impairment due to neuro-degenerative disorders such as Parkinson's Disease (PD) leads to restricted gait patterns, fall-related injuries, decreased mobility, and loss of functional independence. Though several clinical and posturographic studies have attempted to reveal the complex pathophysiology involved in PD, the diversity of Parkinsonian population makes them unclear and sometimes even contradictory. For instance, studies related to the Center of Pressure (CoP) sway during quiet stance in PD patients highlight both increase and reduction of magnitude in contrast to age-matched healthy individuals. A possible explanation for this contradiction is presented in this article. While the presence of intermittent control has been observed in postural control in human quiet stance, we hypothesize that one of the factors that affects postural instability in PD might be the increase in intermittency in active feedback control. Using a simulation model representing the Anterior-Posterior dynamics of human quiet standing, the intermittent control strategy is first contrasted against continuous control strategy in terms of stability, energy efficiency and settling time, thus establishing the inherent advantages of an intermittent control strategy. Further, the ability of the intermittent control strategy to explain several clinical observations in PD is demonstrated. An experimental pilot study is also conducted to support the simulation study, and several body sway parameters derived from recordings of CoP are presented. The presented results are in close agreement with reported clinical observations and may also prove useful for the assessment of disease progression and future fall risk.
journal_name
J Biomechjournal_title
Journal of biomechanicsauthors
Dash R,Shah VV,Palanthandalam-Madapusi HJdoi
10.1016/j.jbiomech.2020.109791subject
Has Abstractpub_date
2020-05-22 00:00:00pages
109791eissn
0021-9290issn
1873-2380pii
S0021-9290(20)30211-6journal_volume
105pub_type
杂志文章abstract::Spinal stability is related to the recruitment and control of active muscle stiffness. Stochastic system identification techniques were used to calculate the effective stiffness and dynamics of the trunk during active trunk extension exertions. Twenty-one healthy adult subjects (10 males, 11 females) wore a harness wi...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2004.09.014
更新日期:2005-10-01 00:00:00
abstract::Determination of contact areas in diarthrodial joints is necessary for understanding the state of stress within the articular cartilage layers and the supporting bony structures. The present study describes the use of a stereophotogrammetry (SPG) system [Huiskes et al., J. Biomechanics 18, 559-570 (1985) and Ateshian ...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/0021-9290(94)90038-8
更新日期:1994-01-01 00:00:00
abstract::The purpose of this project was to study a noninvasive method of evaluating limbs at risk of compartment syndrome. Untreated limb compartment syndrome may lead to irreversible dysfunction, chronic pain and contracture. An improved means of obtaining quantitative hardness measurements is reported. The handheld noninvas...
journal_title:Journal of biomechanics
pub_type: 临床试验,杂志文章
doi:10.1016/j.jbiomech.2004.07.030
更新日期:2005-08-01 00:00:00
abstract::The anatomy of the distal femur has a predominant influence on the mechanics of both patello- and tibio-femoral joints. Especially, the morphological degeneration of the trochlear region dramatically affects the overall knee biomechanics and, from a clinical point of view, the staging of such a degeneration is fundame...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2019.07.008
更新日期:2019-09-20 00:00:00
abstract::About one-third of older multiparous women are prone to stress urinary incontinence (SUI): unwanted urine loss during activities which suddenly raise intra-abdominal pressure. In this paper we describe and test a method for visualizing and analyzing the function of the urinary continence control system (CCS) under str...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/s0021-9290(97)81291-2
更新日期:1997-01-01 00:00:00
abstract::Electromyography (EMG) biofeedback training affords patients a better sense of the different muscle activation patterns involved in the movement of the shoulder girdle. It is important to address scapular kinematics with labourers who have daily routines involving large amounts of lifting at shoulder level or higher. ...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2016.04.036
更新日期:2016-06-14 00:00:00
abstract::In this study, the effect of dehydration-hydration based sublamellar dimensional change on bone anisotropy was used as a tool to understand sublamellar organization of mineralized collagen fibrils. Bone consists of hydroxyapatite, Type I Collagen, mucopolysaccharides and bone fluid, which associates with bone constitu...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2020.109737
更新日期:2020-05-07 00:00:00
abstract::The topographical distributions of the zonal properties of articular cartilage over the medial tibia from an experimental osteoarthritis (OA) model were evaluated as a function of external loading by microscopic Magnetic Resonance Imaging (µMRI). T2 relaxation times and cartilage thicknesses were measured at 17.6 µm r...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2015.08.011
更新日期:2015-10-15 00:00:00
abstract::Cellular mechanics is known to play an important role in many cellular functions including adhesion, migration, proliferation, and differentiation. Human mesenchymal stem cells (hMSCs) demonstrate unique mechanical properties distinct from fully differentiated cells. This observation suggests that the stem cell mechan...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2011.07.024
更新日期:2011-10-13 00:00:00
abstract::The purpose of this study was to predict and explain the pattern of shear force and ligament loading in the ACL-deficient knee during walking, and to compare these results to similar calculations for the healthy knee. Musculoskeletal modeling and computer simulation were combined to calculate ligament forces in the AC...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2003.07.001
更新日期:2004-03-01 00:00:00
abstract::Anterior cruciate ligament (ACL) volume and T2∗ relaxation times from magnetic resonance (MR) images have been previously shown to predict the structural properties of healing ligaments. We investigated whether MR imaging scan resolution and condition (in vivo, in situ, or ex vivo) affected ACL volume and T2∗ relaxati...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2017.03.010
更新日期:2017-05-03 00:00:00
abstract::Three recent studies reveal that the unloaded length of a carotid artery increases significantly and rapidly in response to sustained increases in axial extension. Moreover, such lengthening involves an "unprecedented" increase in the rate of turnover of cells and matrix. Although current data are not sufficient for d...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2004.06.017
更新日期:2005-06-01 00:00:00
abstract::Sustained mechanical loading of skeletal muscle may result in the development of a severe type of pressure ulcer, referred to as deep tissue injury. Recently it was shown that the diffusion of large molecules (10-150kDa) is impaired during deformation of tissue-engineered skeletal muscle, suggesting a role for impaire...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2009.07.043
更新日期:2010-02-10 00:00:00
abstract::Arterial embolism is responsible for the death of lots of people who suffers from heart diseases. The major risk of embolism in upper limbs is that the ruptured particles are brought into the brain, thus stimulating neurological symptoms or causing the stroke. We presented a computational model using fluid-structure i...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2012.01.020
更新日期:2012-04-30 00:00:00
abstract::Experimental tests, such as the confined and unconfined compression and the indentation tests, are traditionally used to determine the poroelastic properties of hydrated soft tissues (HSTs). The purpose of this study was to quantitatively evaluate the reliability of H(A) and K values as identified from experimental co...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2007.02.020
更新日期:2007-01-01 00:00:00
abstract::Tendon curvature plays a key role in mechanical gain (amplifying the joint excursion relative to fiber length change) during joint motion, but the mechanism remains unresolved. A three-dimensional finite element (FE) model was used to investigate the influence of intramuscular fiber orientation upon the curvature patt...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2016.09.014
更新日期:2016-10-03 00:00:00
abstract::Muscle force is modulated by varying the number of active motor units and their firing rates. For the past five decades, the notion that the magnitude of the firing rates is directly related to motor unit size and recruitment threshold has been widely accepted. This construct, here named the After-hyperpolarization sc...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2014.12.003
更新日期:2015-01-21 00:00:00
abstract::This study was mainly performed to investigate the effects of high maxillary expansion forces on the skull with fresh and thiel-fixed human skulls. The maxillary suture was not weakened except in one experiment. This study compares the strain measured on the zygomatic process of the skull with the results of a finite ...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2010.02.002
更新日期:2010-05-07 00:00:00
abstract::Subject-specific musculoskeletal models require accurate values of muscle moment arms. The aim of this study was to compare moment arms of wrist tendons obtained from non-invasive magnetic resonance imaging (MRI) to those obtained from an in vitro experimental approach. MRI was performed on ten upper limb cadaveric sp...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2017.12.024
更新日期:2018-02-08 00:00:00
abstract::Age-related changes in bone quality are mainly manifested in the reduced toughness. Since the post-yield deformation of bone is realized through microdamage formation (e.g., microcracking and diffuse damage), it is necessary to understand the mechanism of microdamage formation in bone in order to elucidate underlying ...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2005.01.009
更新日期:2006-01-01 00:00:00
abstract::Human responses are critical to understanding injury biomechanics in blunt ballistic impacts, which are defined as 20-200 g projectiles impacting at 20-250 m/s. 13 human cadavers were exposed to three distinct ballistic impacts of the chest to determine force-time, deflection-time and force-deflection responses. Compa...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/s0021-9290(03)00238-0
更新日期:2004-01-01 00:00:00
abstract::Repeated loading of the fingertips has been postulated to contribute to tendon and nerve disorders at the wrist during activities associated with prolonged fingertip loading such as typing. To fully understand the pathomechanics of these soft tissue disorders, the role of the fingertip pulp in attenuating the applied ...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/s0021-9290(97)00065-1
更新日期:1997-10-01 00:00:00
abstract::The objective of this study was to determine the intervertebral kinematics of the young, healthy cervical spine during dynamic, three-dimensional, functional loading. Intervertebral motion was characterized by the range of motion (ROM) and the helical axis of motion (HAM). Biplane radiographs of the cervical spine wer...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2015.02.049
更新日期:2015-05-01 00:00:00
abstract::In this study we investigated the time course of length and velocity of muscle fascicles and tendinous tissues (TT) during isometric twitch contraction, and examined how their interaction relates to the time course of external torque and muscle fascicle force generation. From seven males, supra-maximal twitch contract...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2007.03.023
更新日期:2007-01-01 00:00:00
abstract::Evaluation of postural control is generally based on the interpretation of the center of pressure (COP) and the center of mass (COM) time series. The purpose of this study is to compare three methods to estimate the COM which are based on different biomechanical considerations. These methods are: (1) the kinematic met...
journal_title:Journal of biomechanics
pub_type: 临床试验,杂志文章
doi:10.1016/S0021-9290(03)00251-3
更新日期:2004-09-01 00:00:00
abstract::Platelet activation under blood flow is thought to be critically dependent on the autologous secretion of soluble platelet agonists (chemical activators) such as ADP and thromboxane. However, recent evidence challenging this model suggests that platelet activation can occur independent of soluble agonist signalling, i...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2011.02.006
更新日期:2011-04-07 00:00:00
abstract::Nerve compression due to intervertebral disc (IVD) bulging is a known mechanism for low back pain and typically occurs in the posterior region of the disc. Most in vitro studies are limited in the ability to quantify the magnitude of bulging on the posterior aspect of the disc due to the boney structures that occlude ...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2020.109713
更新日期:2020-05-07 00:00:00
abstract::A fast (0.1 mm steps within 2 ms), strong (40 N continuously) and accurate (resolution 0.002 N and 1.0 micron) muscle ergometer was developed to test dynamic and static properties of mammalian muscle. Both for twitches and for tetani isometric, isokinetic and isotonic contractions can be measured accurately. Force-vel...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/0021-9290(87)90312-5
更新日期:1987-01-01 00:00:00
abstract::Little information is available on the direction-dependency of shear behavior in mandibular condylar cartilage. Therefore, we tested the hypothesis that such a dependency of the dynamic shear properties is present in mandibular condylar cartilage. From each of 17 condyles, two cartilage-bone plugs were dissected and t...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2007.12.012
更新日期:2008-01-01 00:00:00
abstract::Current clinical practice lacks an accurate predictor for the pathological fracture risk in metastatic bone disease, but biomechanical tools are under development to improve these predictions. In this paper we explain the limitations of currently used clinical guidelines and provide an overview of more objective and q...
journal_title:Journal of biomechanics
pub_type: 杂志文章
doi:10.1016/j.jbiomech.2014.12.017
更新日期:2015-03-18 00:00:00