Study of the optimum level of electrode placement for the evaluation of absolute lung resistivity with the Mk3.5 EIT system

2006 ◽  
Vol 27 (5) ◽  
pp. S129-S137 ◽  
Author(s):  
S Nebuya ◽  
M Noshiro ◽  
A Yonemoto ◽  
S Tateno ◽  
B H Brown ◽  
...  
Keyword(s):  
Electrode Placement ◽  
Optimum Level ◽  
Lung Resistivity

Temporal-Gap Detection by Cochlear Prosthesis Users

1989 ◽  
Vol 32 (4) ◽  
pp. 849-856 ◽  
Author(s):  
John P. Preece ◽  
Richard S. Tyler
Keyword(s):  
Magnitude Estimation ◽  
Stimulus Level ◽  
Electrode Placement ◽  
Frequency Effect ◽  
Gap Detection ◽  
Cochlear Prosthesis ◽  
Sensation Level

Minimum-detectable gaps for sinusoidal stimuli were measured for three users of a multi electrode cochlear prosthesis as functions of stimulus level, frequency, and electrode place within the cochlea. Stimulus level was scaled by sensation level and by growth-of-loudness functions generated for each condition by direct magnitude estimation. Minimum-detectable gaps decreased with increase in either sensation level or loudness, up to a plateau. When compared at equal sensation levels, the minimum-detectable gaps decreased with frequency increases. The frequency effect on minimum-detectable gaps is reduced if the data are considered at equal loudness. Comparison across place of stimulation within the cochlea showed minimum-detectable gaps to be shorter for more basal electrode placement at low stimulus levels. No differences in minimum-detectable gap as a function of place were found at higher stimulus levels.

NON-INVASIVE BCI METHOD: EEG - ELECTROENCEPHALOGRAPHY

2019 ◽  
pp. 139-145
Author(s):  
Selma Büyükgöze
Keyword(s):  
Brain Computer Interface ◽  
Computer Interface ◽  
Electrode Placement ◽  
Eeg Signals ◽  
Non Invasive ◽  
Brain Signals ◽  
Brain States ◽  
The Brain

Brain Computer Interface consists of hardware and software that convert brain signals into action. It changes the nerves, muscles, and movements they produce with electro-physiological signs. The BCI cannot read the brain and decipher the thought in general. The BCI can only identify and classify specific patterns of activity in ongoing brain signals associated with specific tasks or events. EEG is the most commonly used non-invasive BCI method as it can be obtained easily compared to other methods. In this study; It will be given how EEG signals are obtained from the scalp, with which waves these frequencies are named and in which brain states these waves occur. 10-20 electrode placement plan for EEG to be placed on the scalp will be shown.

Accuracy of robot-assisted versus optical frameless navigated stereoelectroencephalography electrode placement in children

2019 ◽  
Vol 23 (3) ◽  
pp. 297-302 ◽  
Author(s):  
Julia D. Sharma ◽  
Kiran K. Seunarine ◽  
Muhammad Zubair Tahir ◽  
Martin M. Tisdall
Keyword(s):  
Soft Tissue ◽  
Entry Point ◽  
Electrode Placement ◽  
Target Point ◽  
Localization Error ◽  
Bone Thickness ◽  
Tissue Thickness ◽  
Robot Assisted ◽  
Soft Tissue Thickness ◽  
Safety Margins

OBJECTIVEThe aim of this study was to compare the accuracy of optical frameless neuronavigation (ON) and robot-assisted (RA) stereoelectroencephalography (SEEG) electrode placement in children, and to identify factors that might increase the risk of misplacement.METHODSThe authors undertook a retrospective review of all children who underwent SEEG at their institution. Twenty children were identified who underwent stereotactic placement of a total of 218 electrodes. Six procedures were performed using ON and 14 were placed using a robotic assistant. Placement error was calculated at cortical entry and at the target by calculating the Euclidean distance between the electrode and the planned cortical entry and target points. The Mann-Whitney U-test was used to compare the results for ON and RA placement accuracy. For each electrode placed using robotic assistance, extracranial soft-tissue thickness, bone thickness, and intracranial length were measured. Entry angle of electrode to bone was calculated using stereotactic coordinates. A stepwise linear regression model was used to test for variables that significantly influenced placement error.RESULTSBetween 8 and 17 electrodes (median 10 electrodes) were placed per patient. Median target point localization error was 4.5 mm (interquartile range [IQR] 2.8–6.1 mm) for ON and 1.07 mm (IQR 0.71–1.59) for RA placement. Median entry point localization error was 5.5 mm (IQR 4.0–6.4) for ON and 0.71 mm (IQR 0.47–1.03) for RA placement. The difference in accuracy between Stealth-guided (ON) and RA placement was highly significant for both cortical entry point and target (p < 0.0001 for both). Increased soft-tissue thickness and intracranial length reduced accuracy at the target. Increased soft-tissue thickness, bone thickness, and younger age reduced accuracy at entry. There were no complications.CONCLUSIONSRA stereotactic electrode placement is highly accurate and is significantly more accurate than ON. Larger safety margins away from vascular structures should be used when placing deep electrodes in young children and for trajectories that pass through thicker soft tissues such as the temporal region.

Utility of depth electrode placement in the neurosurgical management of bottom-of-sulcus lesions: technical note

2019 ◽  
Vol 24 (3) ◽  
pp. 284-292
Author(s):  
Eisha A. Christian ◽  
Elysa Widjaja ◽  
Ayako Ochi ◽  
Hiroshi Otsubo ◽  
Stephanie Holowka ◽  
...  
Keyword(s):  
Pediatric Patients ◽  
Focal Cortical Dysplasia ◽  
Target Identification ◽  
Cortical Dysplasia ◽  
Technical Note ◽  
Electrode Placement ◽  
Electrode Implantation ◽  
Depth Electrodes ◽  
Intracranial Electrode ◽  
The Brain

OBJECTIVESmall lesions at the depth of the sulcus, such as with bottom-of-sulcus focal cortical dysplasia, are not visible from the surface of the brain and can therefore be technically challenging to resect. In this technical note, the authors describe their method of using depth electrodes as landmarks for the subsequent resection of these exacting lesions.METHODSA retrospective review was performed on pediatric patients who had undergone invasive electroencephalography with depth electrodes that were subsequently used as guides for resection in the period between July 2015 and June 2017.RESULTSTen patients (3–15 years old) met the criteria for this study. At the same time as invasive subdural grid and/or strip insertion, between 2 and 4 depth electrodes were placed using a hand-held frameless neuronavigation technique. Of the total 28 depth electrodes inserted, all were found within the targeted locations on postoperative imaging. There was 1 patient in whom an asymptomatic subarachnoid hemorrhage was demonstrated on postprocedural imaging. Depth electrodes aided in target identification in all 10 cases.CONCLUSIONSDepth electrodes placed at the time of invasive intracranial electrode implantation can be used to help localize, target, and resect primary zones of epileptogenesis caused by bottom-of-sulcus lesions.

The Role of Entrepreneurship in Local Economic Growth: Example of Gaziantep

2012 ◽  
Author(s):  
Mehmet Vahit Eren ◽  
Erdinç Tutar ◽  
Filiz Tutar ◽  
Çisil Erkan
Keyword(s):  
Swot Analysis ◽  
Vital Role ◽  
Local Economy ◽  
Government Policies ◽  
Optimum Level ◽  
Economic Sectors ◽  
Local Economies ◽  
The Status ◽  
Financial Growth

In order to avoid social inequality of opportunity and improvement of local economies have become government policies in Turkey, as it is in other countries around the world. Incentives, regional development agencies, techno parks and also local entrepreneurs play crucial role in the improvement process of local economies. The increasing rivalry and globalization concept necessitate entrepreneurs to take more risks, to reach innovations to seize opportunities in optimum level. Entrepreneurship is a motor vessel in financial growth and in development, and entrepreneurship is also the source of innovation and creativity. In this regard, the more entrepreneurship develops in a country, the higher level of welfare possesses the chance to advance. The purpose of this report, in which it has been aimed to reveal vital role of entrepreneurship in the progress of local economies, is emphasizing the status of entrepreneurship that transformed Gaziantep’s socio-economic level of development into its present position. Thus with this aim a SWOT analysis, in terms of Gaziantep’s economic entrepreneurship has been carried out. Positive contributions of Gaziantep’s immensely developed industry, facilitation of local innovative entrepreneurs’ involvement in various local economic sectors and in accordance channeling immigration into deployment in local economy have been observed in this study. Significantly it has been observed that plenitude of “opportunist entrepreneurship” or in other words “the entrepreneurs with strategic growth plans” in this region contributed local economy positively.

scholarly journals Of pride and prejudice: agent learning under sticky and persistent stereotype

2021 ◽  
Vol 16 (2) ◽  
pp. 381-410
Author(s):  
Georg D. Blind ◽  
Stefania Lottanti von Mandach
Keyword(s):  
Maximum Likelihood ◽  
Private Equity ◽  
Optimum Level ◽  
Pride And Prejudice ◽  
Anglo Saxon ◽  
Agent Learning ◽  
Economic Interaction ◽  
Level Of Effort ◽  
Group Agents ◽  
A Share

AbstractStereotypes matter for economic interaction if counterparty utility is informed by factors other than price. Stereotyped agents may engage in efforts to counter stereotype by adapting to in-group standards. We present a model informing the optimal extent of these efforts depending on an agent’s (a) share of total transactions between out- and in-group agents; and (b) share of repeated transaction pairings with in-group counterparties. Low values of (a) suppress the effect of adaptation efforts on the stereotype itself (persistence). In turn, low values of (b) mean that out-group agents cannot dissociate from stereotype (stickiness). Significantly, the model implies that the optimum level of effort may require adaptation beyond in-group standards, and that such over-adaptation attains maximum likelihood in cases where stereotype is sticky and persistent at the same time. We test our model with data on private equity buyout investments conducted in Japan between 1998 and 2015 by domestic Japanese and Anglo-Saxon funds. We document that the latter not only adapt, but eventually over-adapt. In addition, we show that their efforts are effective in reducing a premium initially asked by domestic counterparties.

Surgical considerations during cochlear implantation: the utility of temporal bone computed tomography

2021 ◽  
pp. 1-8
Author(s):  
Beomcho Jun ◽  
Sunwha Song
Keyword(s):  
Computed Tomography ◽  
Temporal Bone ◽  
Cochlear Implantation ◽  
Round Window ◽  
Three Dimensional ◽  
Electrode Placement ◽  
Posterior Tympanotomy ◽  
Electrode Insertion ◽  
Window Approach ◽  
Bone Structures

Abstract Objective This paper describes the construction of portals for electrode placement during cochlear implantation and emphasises the utility of pre-operative temporal bone three-dimensional computed tomography. Methods Temporal bone three-dimensional computed tomography was used to plan portal creation for electrode insertion. Results Pre-operative temporal bone three-dimensional computed tomography can be used to determine the orientation of temporal bone structures, which is important for mastoidectomy, posterior tympanotomy and cochleostomy, and when using the round window approach. Conclusion It is essential to create appropriate portals (from the mastoid cortex to the cochlea) in a step-by-step manner, to ensure the safe insertion of electrodes into the scala tympani. Pre-operative three-dimensional temporal bone computed tomography is invaluable in this respect.

Quantifying the effects of electrode placement and montage on measures of cVEMP amplitude and muscle contraction

2020 ◽  
pp. 1-13
Author(s):  
Sendhil Govender ◽  
Sally M. Rosengren
Keyword(s):  
Muscle Contraction ◽  
Normal Subjects ◽  
Electrode Placement ◽  
Electrode Position ◽  
Test Results ◽  
Vestibular Evoked Myogenic Potential ◽  
Active Electrode ◽  
Myogenic Potential ◽  
Position Errors ◽  
Test Outcomes

BACKGROUND: The cervical vestibular evoked myogenic potential (cVEMP) can be affected by the recording parameters used to quantify the response. OBJECTIVE: We investigated the effects of electrode placement and montage on the variability and symmetry of sternocleidomastoid (SCM) contraction strength and cVEMP amplitude. METHODS: We used inter-side asymmetries in electrode placement to mimic small clinical errors in twenty normal subjects. cVEMPs were recorded at three active electrode sites and referred to the distal SCM tendon (referential montages: upper, conventional and lower). Additional bipolar montages were constructed offline to measure SCM contraction strength using closely-spaced electrode pairs (bipolar montages: superior, lower and outer). RESULTS: The conventional montage generally produced the largest cVEMP amplitudes (P <  0.001). SCM contraction strength was larger for referential montages than bipolar ones (P <  0.001). Inter-side electrode position errors produced large variations in cVEMP and SCM contraction strength asymmetries in some subjects, producing erroneous abnormal test results. CONCLUSION: Recording locations affect cVEMP amplitude and SCM contraction strength. In most cases, small changes in electrode position had only minor effects but, in a minority of subjects, the different montages produced large changes in cVEMP and contraction amplitudes and asymmetry, potentially affecting test outcomes.

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