Simulations to study spatial extent of stimulation and effect of electrode-tissue gap in subretinal implants.

Abstract:

:We present a finite element based simulation and analysis method to describe the spatial extent of stimulation and the effects of electrode-tissue interactions in subretinal prostheses. In particular, we estimate the threshold stimulation current needed to depolarise and evoke action potentials in the ganglion cells to be stimulated at a particular distance from the electrode. This is achieved through the application of a threshold electric field to a spherical neuronal soma model of a retinal ganglion cell under consideration. Threshold stimulation currents and the lateral extent of the stimulation zone were computed for disc microelectrodes in subretinal stimulation mode. Recent evidence indicates a decrease in threshold charge with time following subretinal implantation. Consequently, to explain the variation in threshold stimulation currents, we propose a hypothesis based on an electrode-tissue gap. Threshold stimulation currents and impedances for different electrode-tissue gaps were computed. We validate the hypothesis with our simulation results that the changes in impedance observed with time in vivo can be mainly attributed to the varying distance of the ganglion cells from electrodes due to changes in electrode-tissue gap. Our simulation framework proposes a convenient and practical method applicable for studying different electrode geometries used for retinal stimulation.

journal_name

Med Eng Phys

authors

Kasi H,Bertsch A,Guyomard JL,Kolomiets B,Picaud S,Pelizzone M,Renaud P

doi

10.1016/j.medengphy.2011.01.015

subject

Has Abstract

pub_date

2011-07-01 00:00:00

pages

755-63

issue

6

eissn

1350-4533

issn

1873-4030

pii

S1350-4533(11)00019-1

journal_volume

33

pub_type

杂志文章
  • Biomechanical design using in-vitro finite element modeling of distal femur fracture plates made from semi-rigid materials versus traditional metals for post-operative toe-touch weight-bearing.

    abstract::This proof-of-concept study designs distal femur fracture plates from semi-rigid materials vs. traditional metals for toe-touch weight-bearing recommended to patients immediately after surgery. The two-fold goal was to (a) reduce stress shielding (SS) by increasing cortical bone stress thereby reducing the risk of bon...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2020.11.015

    authors: Gee A,Bougherara H,Schemitsch EH,Zdero R

    更新日期:2021-01-01 00:00:00

  • Magnetic resonance-based thermometry during laser ablation on ex-vivo swine pancreas and liver.

    abstract::Laser Ablation (LA) is a minimally-invasive procedure for tumor treatment. LA outcomes depend on the heat distribution inside tissues and require accurate temperature measurement during the procedure. Magnetic resonance imaging (MRI) allows a non-invasive and three-dimensional thermometry of the organ undergoing LA. I...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2015.04.001

    authors: Allegretti G,Saccomandi P,Giurazza F,Caponero MA,Frauenfelder G,Di Matteo FM,Beomonte Zobel B,Silvestri S,Schena E

    更新日期:2015-07-01 00:00:00

  • Relationship between architectural parameters and sample volume of human cancellous bone in micro-CT scanning.

    abstract::Truly representative architectural parameters of trabeculea can be extremely difficult to achieve based on scanning images because of variable porosity and distribution of trabeculae within the specific overall scanned volume of bone. Accordingly, in present study different selective volume of interests, measured from...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2011.01.014

    authors: Yan YB,Qi W,Wang J,Liu LF,Teo EC,Tianxia Q,Ba JJ,Lei W

    更新日期:2011-07-01 00:00:00

  • Determination of the position and orientation of artificial knee implants using markers embedded in a bone: preliminary in vitro experiments.

    abstract::This study describes the method of determination of the position and orientation of artificial knee implants using a single-plane radiograph. To simplify the 3D/2D matching problem, we proposed to use small markers embedded in a bone. From the image coordinates of markers, it is possible to estimate the position and o...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/s1350-4533(03)00037-7

    authors: Imai S,Higashijima K,Ishida A,Fukuoka Y,Hoshino A,Minamitani H

    更新日期:2003-06-01 00:00:00

  • Mechanical characterization of bone anchors used with a bone-attached, parallel robot for skull surgery.

    abstract::Bone-attached robots and microstereotactic frames, intended for deep brain stimulation and minimally invasive cochlear implantation, typically attach to a patient's skull via bone anchors. A rigid and reliable link between such devices and the skull is mandatory in order to fulfill the high accuracy demands of minimal...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2015.02.012

    authors: Kobler JP,Prielozny L,Lexow GJ,Rau TS,Majdani O,Ortmaier T

    更新日期:2015-05-01 00:00:00

  • On the secondary stability of coated cementless hip replacement: parameters that affected interface strength.

    abstract::Unlike primary stability of coated cementless implants, their secondary stability has been poorly studied. This paper considers some theoretical aspects of the secondary stability of a coated cementless hip implant in a human femur. The bone is separated from the implant by a thin layer of microscopic peaks and trough...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/s1350-4533(03)00099-7

    authors: Orlik J,Zhurov A,Middleton J

    更新日期:2003-12-01 00:00:00

  • A multi-sample denaturation temperature tester for collagenous biomaterials.

    abstract::The temperature at which collagen denatures from a triple helix to a random coil structure is a useful measure of the degree of crosslinking. A new multi-sample denaturation temperature tester (DTT) has been constructed for rapid determination of the collagen denaturation temperature of natural tissues and collagenous...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/1350-4533(95)91882-h

    authors: Lee JM,Pereira CA,Abdulla D,Naimark WA,Crawford I

    更新日期:1995-03-01 00:00:00

  • Shape-memory-alloy-based smart knee spacer for total knee arthroplasty: 3D CAD modelling and a computational study.

    abstract::This study introduced a shape memory alloy (SMA)-based smart knee spacer for total knee arthroplasty (TKA). Subsequently, a 3D CAD model of a smart tibial component of TKA was designed in Solidworks software, and verified using a finite element analysis in ANSYS Workbench. The two major properties of the SMA (NiTi), t...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2018.03.001

    authors: Gautam A,Callejas MA,Acharyya A,Acharyya SG

    更新日期:2018-05-01 00:00:00

  • Sonomyography: monitoring morphological changes of forearm muscles in actions with the feasibility for the control of powered prosthesis.

    abstract::Electromyography (EMG) has been widely used for the assessment of musculoskeletal functions and the control of electrical prostheses, which make use of the EMG signal generated by the contraction of the residual muscles. In spite of the successful applications of EMG in different fields, it has some inherent limitatio...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2005.07.012

    authors: Zheng YP,Chan MM,Shi J,Chen X,Huang QH

    更新日期:2006-06-01 00:00:00

  • Intramedullary femoral nails: one or two lag screws? A preliminary study.

    abstract::Failures of proximal femoral nails that treat unstable femoral fractures have been reported. In this communication, a finite element model to include a proximal femoral nail within a fractured femur was used to carry out preliminary investigations into configurations of single or double lag screws. The effects of the ...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/s1350-4533(00)00081-3

    authors: Wang CJ,Brown CJ,Yettram AL,Procter P

    更新日期:2000-11-01 00:00:00

  • Reconstruction of proximal humeral fractures with a reduced number of screws and a reinforced bone substitute.

    abstract::Multi-fragmented fractures of the proximal humerus are difficult to treat, especially in the case of osteoporotic bone. Intra-operative risks include cartilage damage when inserting multiple screws. A common post-operative complication is distal-varus collapse of the head. The aim of this study was to investigate if a...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2020.06.002

    authors: Cristofolini L,Morellato K,Cavallo M,Guerra E

    更新日期:2020-08-01 00:00:00

  • Sensitivity analysis of the position of the intervertebral centres of reaction in upright standing--a musculoskeletal model investigation of the lumbar spine.

    abstract::The loads between adjacent vertebrae can be generalised as a single spatial force acting at the intervertebral centre of reaction. The exact position in vivo is unknown. However, in rigid body musculoskeletal models that simulate upright standing, the position is generally assumed to be located at the discs' centres o...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2015.12.003

    authors: Zander T,Dreischarf M,Schmidt H

    更新日期:2016-03-01 00:00:00

  • Comparison of isotropic and orthotropic material property assignments on femoral finite element models under two loading conditions.

    abstract::CT data has been widely used in the finite element modeling of bone. It can provide useful information on the geometrical topology and material properties of bone. Based on CT data, the assignment of bone material properties to finite element meshes is a fundamental step in the model generation. Most work done in this...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2005.06.003

    authors: Peng L,Bai J,Zeng X,Zhou Y

    更新日期:2006-04-01 00:00:00

  • Protocol development for synchrotron contrast-enhanced CT of human hip cartilage.

    abstract::Understanding hip osteoarthritis requires new investigational tools for quantitative studies of biophysical and biomechanical properties as well as for determination of structure. Three new protocols to study pathological changes in cartilage and to measure cartilage thickness in intact human hips are described using ...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2019.08.003

    authors: Zhang H,Belev G,Stewart RC,Grinstaff MW,Snyder BD,Wilson DR

    更新日期:2019-11-01 00:00:00

  • A new MR-compatible loading device to study in vivo muscle damage development in rats due to compressive loading.

    abstract::To study the aetiology of pressure ulcers an MR-compatible loading device was developed. Magnetic resonance imaging provides the possibility of non-invasive evaluation of muscle tissue after compressive loading. Pressure was applied to the tibialis anterior region of rats by means of an indenter. The developed MR-comp...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2005.07.005

    authors: Stekelenburg A,Oomens CW,Strijkers GJ,de Graaf L,Bader DL,Nicolay K

    更新日期:2006-05-01 00:00:00

  • A method for the extraction of an object from a noisy background.

    abstract::The removal of the background from a noisy image to leave the object of interest, with well defined edges, is a difficult task. Images obtained using radioisotopes have low signal-to-noise ratios due to scattered photons, as well as emitted radiation from the background. Moreover, noise is, also, a consequence of the ...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/1350-4533(95)00043-7

    authors: Livieratos GN,Chappell PH

    更新日期:1996-03-01 00:00:00

  • Combining ultrasonic and computed tomography scanning to characterize mechanical properties of cancellous bone in necrotic human femoral heads.

    abstract::Image-based finite element modelling has been commonly used to determine the biomechanical behaviours of human femora, particularly for the diagnosis of femoral head necrosis. One of the fundamental aspects of biomechanical modelling is the relationship between bone density, which is obtained from images, and elastic ...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2019.02.002

    authors: Yue Y,Yang H,Li Y,Zhong H,Tang Q,Wang J,Wang R,He H,Chen W,Chen D

    更新日期:2019-04-01 00:00:00

  • Clinical workflow for personalized foot pressure ulcer prevention.

    abstract::Foot pressure ulcers are a common complication of diabetes because of patient's lack of sensitivity due to neuropathy. Deep pressure ulcers appear internally when pressures applied on the foot create high internal strains nearby bony structures. Monitoring tissue strains in persons with diabetes is therefore important...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2016.04.017

    authors: Bucki M,Luboz V,Perrier A,Champion E,Diot B,Vuillerme N,Payan Y

    更新日期:2016-09-01 00:00:00

  • Enabling variable-stiffness hand rehabilitation orthoses with dielectric elastomer transducers.

    abstract::Patients affected by motor disorders of the hand and having residual voluntary movements of fingers or wrist can benefit from self-rehabilitation exercises performed with so-called dynamic hand splints. These systems consist of orthoses equipped with elastic cords or springs, which either provide a sustained stretch o...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2013.10.015

    authors: Carpi F,Frediani G,Gerboni C,Gemignani J,De Rossi D

    更新日期:2014-02-01 00:00:00

  • Data dependent random forest applied to screening for laryngeal disorders through analysis of sustained phonation: acoustic versus contact microphone.

    abstract::Comprehensive evaluation of results obtained using acoustic and contact microphones in screening for laryngeal disorders through analysis of sustained phonation is the main objective of this study. Aiming to obtain a versatile characterization of voice samples recorded using microphones of both types, 14 different set...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2014.12.005

    authors: Verikas A,Gelzinis A,Vaiciukynas E,Bacauskiene M,Minelga J,Hållander M,Uloza V,Padervinskis E

    更新日期:2015-02-01 00:00:00

  • Dielectric elastomers as actuators for upper limb prosthetics: challenges and opportunities.

    abstract::Recent research has indicated that consumers of upper limb prostheses desire lighter-weight, anthropomorphic devices. The potential of dielectric elastomer (DE) actuators to better meet the design priorities of prosthesis users is explored. Current challenges are critically reviewed with respect to (1) durability, (2)...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章,评审

    doi:10.1016/j.medengphy.2007.05.011

    authors: Biddiss E,Chau T

    更新日期:2008-05-01 00:00:00

  • TETRA mobile radios interfere with electroencephalography recording equipment.

    abstract::We observed an anomaly in the human electroencephalogram (EEG) associated with exposure to terrestrial trunked radio (TETRA) Radiofrequency Fields (RF). Here, we characterize the time and frequency components of the anomaly and demonstrate that it is an artefact caused by TETRA RF interfering with the EEG recording eq...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2013.04.009

    authors: Fouquet NC,Hawken MB,Elliott P,Burgess AP

    更新日期:2013-11-01 00:00:00

  • Comparing passive angle-torque curves recorded simultaneously with a load cell versus an isokinetic dynamometer during dorsiflexion stretch tolerance assessments.

    abstract::The purpose of the present study was to compare the passive angle-torque curves and the passive stiffness (PS, N m °(-)(1)) values recorded simultaneously from a load cell versus an isokinetic dynamometer during dorsiflexion stretch tolerance assessments in vivo. Nine healthy men (mean ± SD age = 21.4 ± 1.6 years) com...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2015.02.010

    authors: Buckner SL,Jenkins ND,Costa PB,Ryan ED,Herda TJ,Cramer JT

    更新日期:2015-05-01 00:00:00

  • Evaluation of four blood pump geometries: fluorescent particle flow visualisation technique.

    abstract::Artificial blood pumps play an increasingly important role in the treatment of end-stage cardiac failure. The fluid dynamics of blood flow through such devices crucially affects their clinical effectiveness. Specifically, if the flow of blood stagnates or slowly re-circulates thrombus formation can occur and the avoid...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/s1350-4533(00)00023-0

    authors: Rose ML,Mackay TG,Wheatley DJ

    更新日期:2000-04-01 00:00:00

  • Analysis of the effects of surface stiffness on the contact interaction between a finger and a cylindrical handle using a three-dimensional hybrid model.

    abstract::Contact interactions between the hand and handle, such as the contact surface softness and contact surface curvature, will affect both physical effort and musculoskeletal fatigue, thereby the comfort and safety of power tool operations. Previous models of hand gripping can be categorized into two groups: multi-body dy...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2014.03.007

    authors: Wu JZ,Dong RG,Warren CM,Welcome DE,McDowell TW

    更新日期:2014-07-01 00:00:00

  • Application of time-varying analysis to diagnostic needle electromyography.

    abstract::Quantification in clinical, diagnostic electromyography (EMG) currently includes motor unit action potential (MUAP) analysis and interference pattern analysis. Early efforts to examine the frequency/power spectra of the interference pattern showed modest value but the technique was not developed further. This paper re...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2011.07.017

    authors: Sheean GL

    更新日期:2012-03-01 00:00:00

  • Functional evaluation of natural sensory feedback incorporated in a hand grasp neuroprosthesis.

    abstract::We investigated whether automatic control of a hand grasp neuroprosthesis by means of signals from natural sensors in the skin of the index finger can mimic the natural control of grasp force in an important task of daily living, namely eating. We designed a simulated eating task with the same ratio of rest and activi...

    journal_title:Medical engineering & physics

    pub_type: 临床试验,杂志文章

    doi:10.1016/j.medengphy.2004.03.002

    authors: Inmann A,Haugland M

    更新日期:2004-07-01 00:00:00

  • Motion quality evaluation of upper limb target-reaching movements.

    abstract::Fitts' Law was extended in the polar coordinate system, and a set of indices for human motion evaluation is proposed. In this paper, the index of difficulty and the index of performance are introduced as the general indices for the quality measure of plane target-to-target movement. As an example, the target-reaching ...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/s1350-4533(01)00121-7

    authors: Yang N,Zhang M,Huang C,Jin D

    更新日期:2002-03-01 00:00:00

  • Improving the detection of evoked responses to periodic stimulation by using bivariate local spectral F-test - Application to EEG during photic stimulation.

    abstract::The spectral local F-test has been applied for detecting evoked responses to rhythmic stimulation that are embedded in the ongoing electroencephalogram (EEG). Based on the sampling distribution of a flat spectrum at the neighbourhood of the stimulation frequency, spectral peaks in an EEG signal that are due to the sti...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/j.medengphy.2017.06.032

    authors: Felix LB,Rocha PF,Mendes EMAM,Miranda de Sá AMFL

    更新日期:2017-10-01 00:00:00

  • Quantitative CT in the measurement of bone quantity and bone quality for assessing osteoporosis.

    abstract::The biomechanical strength of the skeleton, and hence the risk of future fractures, depends on both the bone quantity (assessed in terms of bone mineral density) and bone quality (assessed in terms of the integrity of its internal architecture). Precise methods of measuring the calcium-equivalent density of both the t...

    journal_title:Medical engineering & physics

    pub_type: 杂志文章

    doi:10.1016/1350-4533(96)00011-2

    authors: Dougherty G

    更新日期:1996-10-01 00:00:00