scholarly journals Investigation of ITD Symmetry in Measured HRIRs

2016 ◽  
Author(s):  
Andrea F. Genovese ◽  
Jordan Juras ◽  
Chris Miller ◽  
Agnieszka Roginska
Keyword(s):  
Interaural Time Difference ◽  
Measurement Techniques ◽  
Just Noticeable Difference ◽  
Non Invasive ◽  
3D Sound ◽  
Left And Right ◽  
The Difference ◽  
Public Datasets ◽  
Invasive Techniques ◽  
The Impact

The Interaural Time Difference is one of the primary localiza- tion cues for 3D sound. However, due to differences in head and ear anthropometry across the population, ITDs related to a sound source at a given location around the head will differ from sub- ject to subject. Furthermore, most individuals do not possess sym- metrical traits between the left and right pinnae. This fact may cause an angle-dependent ITD asymmetry between locations mir- rored across the left and right hemispheres. This paper describes an exploratory analysis performed on publicly available databases of individually measured HRIRs. The analysis was first performed separately for each dataset in order to explore the impact of dif- ferent formats and measurement techniques, and then on pooled sets of repositories, in order to obtain statistical information closer to the population values. Asymmetry in ITDs was found to be consistently more prominent in the rear-lateral angles (approxi- mately between 90° and 130° azimuth) across all databases inves- tigated, suggesting the presence of a sensitive region. A signifi- cant difference between the peak asymmetry values and the aver- age asymmetry across all angles was found on three out of four examined datasets. These results were further explored by pooling the datasets together, which revealed an asymmetry peak at 110° that also showed significance. Moreover, it was found that within the region of sensitivity the difference between specular ITDs ex- ceeds the just noticeable difference values for perceptual discrim- ination at all frequency bands. These findings validate the sta- tistical presence of ITD asymmetry in public datasets of individ- ual HRIRs and identify a significant, perceptually-relevant, region of increased asymmetry. Details of these results are of interest for HRIR modeling and personalization techniques, which should consider implementing compensation for asymmetric ITDs when aiming for perceptually accurate binaural displays. This work is part of a larger study aimed at binaural-audio personalization and user-characterization through non-invasive techniques.

scholarly journals Prevalence and Risk Factors of Discordance between Left- and Right-Hip Bone Mineral Density Using DXA

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Aziza Mounach ◽  
Asmaa Rezqi ◽  
Imad Ghozlani ◽  
Lahsen Achemlal ◽  
Ahmed Bezza ◽  
...  
Keyword(s):  
Bone Mineral Density ◽  
Bone Mineral ◽  
Mineral Density ◽  
Detectable Difference ◽  
Smallest Detectable Difference ◽  
Left And Right ◽  
The Difference ◽  
Highly Correlated ◽  
The Impact ◽  
Confounding Parameters

To determine the prevalence of significant left-right differences in hip bone mineral density (BMD), and the impact of this difference on osteoporosis diagnosis, we measured bilateral proximal femora using dual energy X-ray absorptiometry (DXA) in 3481 subjects (608 males, 2873 females). The difference between left and right hip was considered significant if it exceeded the smallest detectable difference (SDD) for any of the three hip subregions. Contralateral femoral BMD was highly correlated at all measuring sites (–0.95). However, significant left-right differences in BMD were common: the difference exceeded the SDD for 54% of patients at total hip, 52.1% at femoral neck, and 57.7% at trochanter. The prevalence of left-right differences was greater in participants >65 years. For 1169 participants with normal spines, 22 (1.9%) had discordant left-right hips in which one hip was osteoporotic; for 1349 patients with osteopenic spines, 94 (7%) had osteoporosis in one hip. Participants with BMI < 20 kg/m2 were more likely to show major T-score discordance (osteoporosis in one hip and normal BMD in the other). Multiple regression analysis showed that the only significant statically parameter that persists after adjusting for all potential confounding parameters were age over 65 years.

scholarly journals Serum pepsinogen level and abomasal ulcerations in experimental abomasal displacement in sheep

2010 ◽  
Vol 55 (No. 7) ◽  
pp. 311-317 ◽  
Author(s):  
A. Hajimohammadi ◽  
K. Badiei ◽  
K. Mostaghni ◽  
M. Pourjafar
Keyword(s):  
Mucous Membrane ◽  
Surgical Stress ◽  
Serum Pepsinogen ◽  
Blood Samples ◽  
Non Invasive ◽  
Mucosal Change ◽  
Left And Right ◽  
The Right ◽  
Invasive Techniques ◽  
Abomasal Displacement

It is believed that serum pepsinogen levels could be useful for diagnosis of abomasal changes in cattle. Diagnosis of abomasal displacement (AD) is made via invasive and non-invasive techniques. None of the extant methods is a reliable indication of mucosal change. The applicability of serum pepsinogen levels for the diagnosis of changes in the mucous membrane of the abomasum in experimentally induced left and right AD in sheep was investigated in fourteen rams. Abomasal fluid samples were taken and the pH was recorded. Twelve sheep underwent induced left and right AD (six for each group). Two sheep underwent exploratory laparatomy alone to assess the effect of surgical stress on the abomasum. Blood samples were taken before surgery, at the 1<sup>st</sup>, 3<sup>rd</sup>, 5<sup>th</sup>, 7<sup>th</sup>, 9<sup>th</sup> and 11<sup>th</sup> days after surgery and at the time of necropsy and serum pepsinogen levels were measured. After two weeks the animals were slaughtered and abomasal fluid pH and types of abomasal ulcers were recorded. Significant changes in pepsinogen levels in the left displaced abomasums (LDA) group were seen on days 11 and 14 after surgery (P &lt; 0.05). Significant changes in pepsinogen levels in the right displaced abomasum (RDA) group were seen on Days 9, 11 and 14 after surgery (P &lt; 0.05). There was no association among the types of ulcers and the serum pepsinogen levels in AD cases. The pH increased significantly (P &lt; 0.05) after induced AD in both groups. There were no significant changes in serum pepsinogen levels on different days after surgery among ulcerated and non ulcerated cases in both LDA and RDA groups (P &lt; 0.05). Serum pepsinogen levels were significantly higher in AD groups. There was no association between the types of ulcers and serum pepsinogen levels in AD cases. It seems that the increase in concentration of serum pepsinogen is a good reflection of the damage to the abomasal mucousa due to AD, as was shown by the earlier increase in levels in the course of displacement in the RDA group.

scholarly journals Non-Spatial Impairments Affect False-Positive Neglect Diagnosis Based on Cancellation Tasks

2020 ◽  
Vol 26 (7) ◽  
pp. 668-678 ◽  
Author(s):  
Hanne Huygelier ◽  
Margaret Jane Moore ◽  
Nele Demeyere ◽  
Céline R. Gillebert
Keyword(s):  
Test Performance ◽  
False Positive ◽  
Standard Procedure ◽  
Model Performance ◽  
False Positives ◽  
Spatial Bias ◽  
Multiple Tests ◽  
Left And Right ◽  
The Difference ◽  
The Impact

AbstractObjective:To diagnose egocentric neglect after stroke, the spatial bias of performance on cancellation tasks is typically compared to a single cutoff. This standard procedure relies on the assumption that the measurement error of cancellation performance does not depend on non-spatial impairments affecting the total number of cancelled targets. Here we assessed the impact of this assumption on false-positive diagnoses.Method:We estimated false positives by simulating cancellation data using a binomial model. Performance was summarised by the difference in left and right cancelled targets (R-L) and the Centre of Cancellation (CoC). Diagnosis was based on a fixed cutoff versus cutoffs adjusted for the total number of cancelled targets and on single test performance versus unanimous or proportional agreement across multiple tests. Finally, we compared the simulation findings to empirical cancellation data acquired from 651 stroke patients.Results:Using a fixed cutoff, the rate of false positives depended on the total number of cancelled targets and ranged from 10% to 30% for R-L scores and from 10% to 90% for CoC scores. The rate of false positives increased even further when diagnosis was based on proportional agreement across multiple tests. Adjusted cutoffs and unanimous agreement across multiple tests were effective at controlling false positives. For empirical data, fixed versus adjusted cutoffs differ in estimation of neglect prevalence by 13%, and this difference was largest for patients with non-spatial impairments.Conclusions:Our findings demonstrate the importance of considering non-spatial impairments when diagnosing neglect based on cancellation performance.

Review of non-invasive intracranial pressure measurement techniques for ophthalmology applications

2019 ◽  
Vol 104 (7) ◽  
pp. 887-892
Author(s):  
David Andrew Price ◽  
Andrzej Grzybowski ◽  
Jennifer Eikenberry ◽  
Ingrida Januleviciene ◽  
Alice Chandra Verticchio Vercellin ◽  
...  
Keyword(s):  
Intracranial Pressure ◽  
Measurement Techniques ◽  
Optic Nerve Sheath Diameter ◽  
Transcranial Ultrasound ◽  
Invasive Technique ◽  
Non Invasive ◽  
Nerve Sheath ◽  
Assessment And Monitoring ◽  
Invasive Techniques ◽  
The Relationship

Assessment and monitoring of intracranial pressure (ICP) are important in the management of traumatic brain injury and other cerebral pathologies. In the eye, ICP elevation and depression both correlate with optic neuropathies, the former because of papilledema and the latter related to glaucoma. While the relationship between ICP elevation and papilledema is well established, the relationship between low ICP and glaucoma is still poorly understood. So far, ICP monitoring is performed invasively, but this entails risks including infection, spurring the study of non-invasive alternatives. We review 11 methods of non-invasive estimation of ICP including correlation to optic nerve sheath diameter, intraocular pressure, ophthalmodynamometry and two-depth transcranial Doppler of the ophthalmic artery. While none of these methods can fully replace invasive techniques, certain measures show great potential for specific applications. Although only used in small studies to date, a MRI based method known as MR-ICP, appears to be the best non-invasive technique for estimating ICP, with two-depth transcranial ultrasound and ophthalmodynamometry showing potential as well.

scholarly journals Effect of ocular demodicosis on the stability of the tear film and the tear break up time

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aleksandra Sędzikowska ◽  
Witold Tarkowski ◽  
Joanna Moneta-Wielgoś ◽  
Krzysztof Grzyliński ◽  
Grzegorz Tarkowski ◽  
...  
Keyword(s):  
Tear Film ◽  
Hair Follicles ◽  
Film Stability ◽  
Mean Values ◽  
Non Invasive ◽  
Tear Film Stability ◽  
Break Up ◽  
The Difference ◽  
The Stability ◽  
The Impact

AbstractThe aim of the study was to analyze the correlation between the presence of Demodex mites in the hair follicles of patients' eyelashes and the stability and break up time of the tear film assessed with the Non-Invasive Tear Break Up Times (NIBUT) method. 319 patients were included in the study (195 women, 124 men). The patients were divided into two groups: those with Demodex infestation and without visible symptoms of eyelid or eye surface diseases, and asymptomatic non-infested patients. The NIBUT analysis was performed with a 5 M keratograph (oculus). Non-invasive tests were performed to identify the first and mean values of the tear break up time. The first and mean tear break up time in the Demodex-infested group was lower than in the non-infested subjects. The difference was a highly statistically significant. There was a significant correlation with the age of the patients for the first break up time. The first break up time in both eyes decreased with the age of the Demodex-infested and non-infested patients. The NIBUT analyses indicate the impact of Demodex mites on the tear film stability. This may suggest possible association of demodicosis with dry eye syndrome.

The Impact of Advances in Dental Sciences on Primary Dental Care

2000 ◽  
Vol os7 (1) ◽  
pp. 19-22 ◽  
Author(s):  
Crispian Scully
Keyword(s):  
Patient Empowerment ◽  
Diagnostic Procedures ◽  
Therapeutic Agents ◽  
Oral Disease ◽  
Information Revolution ◽  
Record Keeping ◽  
Non Invasive ◽  
Risk Of Disease ◽  
Invasive Techniques ◽  
The Impact

The next century will see phenomenal changes especially and, most importantly, in patient empowerment, in the improvement of health in the disadvantaged, and in the harmonisation of standards of healthcare throughout the world. Advances in the dental sciences will facilitate these improvements but the major changes surely will be largely stimulated and motivated by the information revolution and the advances in molecular and materials sciences. The identification, and protection against disease, of patients who, because of a genetic predisposition, are at particular risk of disease is likely to become possible. Simple, sensitive, effective, non-invasive and safe diagnostic procedures will become available, as will chairside diagnostic test kits that would identify specific microorganisms causal of oral disease. The advances in digital imaging will be taken further and linked to record-keeping. Specific safe agents targeted at responsible microorganisms will be devised, and systems to deliver therapeutic agents effectively and prevent tissue damage simply will be perfected. Painless, minimally-invasive techniques for the removal of diseased oral tissues will become available, as will biocompatible materials for replacement of lost oral tissues.

scholarly journals A Non-Invasive Continuous Blood Pressure Estimation Approach Based on Machine Learning

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2585 ◽  
Author(s):  
Shuo Chen ◽  
Zhong Ji ◽  
Haiyan Wu ◽  
Yingchao Xu
Keyword(s):  
Machine Learning ◽  
Blood Pressure ◽  
Measurement Techniques ◽  
Pulse Transit Time ◽  
Estimation Errors ◽  
British Hypertension Society ◽  
Non Invasive ◽  
Blood Pressure Estimation ◽  
The Impact ◽  
Estimation Models

Considering the existing issues of traditional blood pressure (BP) measurement methods and non-invasive continuous BP measurement techniques, this study aims to establish the systolic BP and diastolic BP estimation models based on machine learning using pulse transit time and characteristics of pulse waveform. In the process of model construction, the mean impact value method was introduced to investigate the impact of each feature on the models and the genetic algorithm was introduced to implement parameter optimization. The experimental results showed that the proposed models could effectively describe the nonlinear relationship between the features and BP and had higher accuracy than the traditional methods with the error of 3.27 ± 5.52 mmHg for systolic BP and 1.16 ± 1.97 mmHg for diastolic BP. Moreover, the estimation errors met the requirements of the Advancement of Medical Instrumentation and British Hypertension Society criteria. In conclusion, this study was helpful in promoting the practical application of methods for non-invasive continuous BP estimation models.

Front–End Design Of An Ultrasonic Tomography Measurement System

2012 ◽  
Author(s):  
Hudabiyah Arshad Amari ◽  
Ruzairi Abdul Rahim ◽  
Mohd Hafiz Fazalul Rahiman ◽  
Jaysuman Pusppanathan
Keyword(s):  
Multiphase Flow ◽  
System Development ◽  
Measurement Techniques ◽  
Ultrasonic Tomography ◽  
Peak Detector ◽  
Non Invasive ◽  
Tomography System ◽  
Sensor Arrangement ◽  
Front End ◽  
Invasive Techniques

Kertas kerja ini menerangkan tentang perancangan bahagian permulaan di dalam sistem tomografi ultrasonik. Dalam kertas kerja ini, teknik perlaksanaan tomografi ultrasonik secara luaran iaitu tidak menggangu aliran dalaman paip diaplikasikan menggunakan 16 sensor gabungan pemancar dan penerima untuk mengesan fasa–fasa aliran di dalam paip. Fasa tersebut termasuk pepejal,gas dan cecair. Kebaikan menggunakan pengesan jenis gabungan berbanding pengesan berasingan dibincangkan di dalam kertas kerja ini. Cara penyusunan pengesan, teknik pengukuran dan penyediaan perkakasan juga dibincangkan. Butir–butir rekaan litar termasuk litar pemancar, penerima, dan litar pengesan puncak juga disertakan. Kertas kerja ini boleh membantu untuk pembinaan sistem tomografi ultrasonik yang lebih jauh. Kata kunci: Tomografi ultrasonic; aliran pelbagai fasa; ultrasonik This paper explains the front–end system design of an ultrasonic tomography. In this paper, the ultrasonic tomography techniques implements a non–invasive techniques which using 16 transceivers to investigate the multiphase flow of the pipelines. The flows include solid, gas and liquid phase in 100 mm pipelines. The advantages of using transceiver rather than separate transmitter receiver are discussed in this paper. The sensor arrangement, measurement techniques and hardware preparation are also discussed in this paper. The circuit design details, including the transmitter, receiver and peak detector are also presented and explained. This paper will be useful for the use of further ultrasonic tomography system development. Key words: Ultrasonic tomography; multiphase flow; non–invasive ultrasonic; transceivers; peak detector

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