Validity and Reliability of the Turkish SingingVoice Handicap Index-10

To evaluate the validity and reliability of the Turkish version of the Singing Voice Handicap Index-10 (SVHI-10).

from Speech via a.sfakia on Inoreader https://ift.tt/2Uqt59e

Stereophotogrammetric analysis of labial morphology in a young adult Middle-Eastern population

The majority of previous research delineating the morphological characteristics of the orolabial region has been on Caucasian populations, with very minor research on Mediterranean populations, and none on the Lebanese population.

from OroFacial via a.sfakia on Inoreader https://ift.tt/2Svxt4U

Developmental defects of enamel in the deciduous incisors of infants born preterm: prospective cohort

Abstract

Objective

Developmental defects of enamel (DDE) in preterm infants still require clarification and may favour dental caries, lower food intake, and greater difficulty with weight‐height gain. We evaluated factors associated with DDE in preterm infants.

Subjects and Methods

In this prospective cohort study, we monitored 54 prematurely born infants from birth to 24 months of age. Trained and calibrated dentists examined the oral cavity of these children to identify and categorize DDE. Information on perinatal variables was collected from the infants' medical records and interviews with their mothers. The data were analysed using Student's t test, a chi‐squared test, and Pearson's product moment correlation coefficient.

Results

A total of 46.3% of the 54 children presented DDE, which was observed more frequently in the left hemiarch in children born extremely (<28 weeks of gestation) or very preterm (28 to <32 weeks) (RR=2.2; 95% CI 1.3‐3.6), with very low birth weight (<1500 g) (RR=2.0; 95% CI 1.1‐3.5), who were admitted to the neonatal intensive care unit (RR=1.3; 95% CI 1.0‐1.7), and who were intubated (RR=1.6; 95% CI 1.1‐2.2).

Conclusions

The high incidence of incisor enamel defects, particularly on the left side, was related to higher risk prematurity and to local trauma from intubation.

This article is protected by copyright. All rights reserved.

from OroFacial via a.sfakia on Inoreader https://ift.tt/2L3Iat6

Local injection of RANKL facilitates tooth movement and alveolar bone remodeling

Abstract

Objectives

To investigate the effect of local injection of receptor activator of nuclear factor kappa B ligand (RANKL) on experimental tooth movement and subsequent alveolar bone remodeling in mice.

Materials and Methods

Sixty mice were randomised to receive daily local RANKL or phosphate‐buffered saline injections in the buccal premaxillary bone for 14 of 21 days of incisor movement, followed by a 21‐day retention period. Five mice from each group were euthanised on days 0, 3, 7, 14, 21, and 42, and specimens were prepared for haematoxylin and eosin, tartrate‐resistant acid phosphatase, and immunohistochemical staining. Five mice from each group were subjected to serial micro‐computed tomography until day 42 for tooth movement and bone volume quantification.

Results

The experimental group showed significantly greater tooth movement and bone volume reduction on days 14 and 21; an increased osteoclast number on days 3, 7, 14, and 21; and no difference on day 42, Higher RANKL expression was observed on days 7 and 14, with remarkable alkaline phosphatase activity. No significant systemic changes were observed.

Conclusion

Local RANKL injection leads to increased osteoclastic activity and facilitates tooth movement, followed by subsequent alveolar bone formation; this implies a reversible transitional acceleration of bone resorption.

This article is protected by copyright. All rights reserved.

from OroFacial via a.sfakia on Inoreader https://ift.tt/2BZX0Op

Velopharyngeal insufficiency after maxillary advancement in patients with cleft palate − a survey of risk assessment in the United Kingdom and Ireland

Patients with cleft lip and palate may require orthognathic surgery to correct severe impairments in midfacial growth. Maxillary advancement in this group, however, is linked to deterioration in velopharyngeal function (VPF), and it is not clear how cleft teams assess this risk. We therefore surveyed surgeons from 15 cleft units who provide orthognathic treatment, to gain an understanding of current practice in the UK and Ireland. A total of 16/21 surgeons from 14/15 units responded. While 14/16 surgeons agreed that these patients are at risk of a deterioration in VPF after maxillary advancement, two disagreed.

from OroFacial via a.sfakia on Inoreader https://ift.tt/2QoFHiL

Full‐arch implant supported rehabilitations: A prospective study comparing porcelain‐veneered zirconia frameworks to monolithic zirconia

Abstract

Objectives

To evaluate the performance of two types of zirconia frameworks.

Material and Methods

From 2014 to 2016, in a prospective clinical trial 150 patients were rehabilitated with 83 and 110 implant‐supported, screw‐retained, full‐arch ceramic‐veneered zirconia (PVZ) rehabilitations and monolithic zirconia with porcelain veneering limited to buccal (MZ) rehabilitations, respectively. Patients were consecutively enlisted according to pre‐defined inclusion criteria and evaluated on 4 months intervals. A Kaplan Meier estimator was adopted, and the log‐rank test and Wilcoxon test used to test differences in survival and successful function in the two different groups.

Results

The average follow up time (+/‐ SD) and implant success rate was 608.80 ± 172.52 days with 99.53% implant success for the PVZ group and 552.63 ± 197.57 days with 99.83% success for the MZ group. According to the Kaplan Meier estimator, the mean cumulative survival rate at the 2 year follow up for framework fracture, major chipping, minor chipping, or any of the former combined to occur was 0.99, 0.95, 0.93 and 0.85 for the PVZ group (n=18) and 0.99, 0.95, 0.95 and 0.89 for the MZ group (n=15). No significant differences were found between the two groups.

Conclusions

Results suggest zirconia as a suitable material for frameworks in full‐arch implant‐supported rehabilitations. Both groups presented a low incidence of technical complications. When comparing the two different designs the MZ group presented a lower technical complication rate, thus presenting itself as a viable alternative for full arch implant‐supported rehabilitations. Further clinical studies with longer follow‐ups (5 years) should be performed to evaluate the long‐term stability of such rehabilitations.

This article is protected by copyright. All rights reserved.

from OroFacial via a.sfakia on Inoreader https://ift.tt/2QinHXo

Mechanical Behavior of Posterior All‐Ceramic Hybrid‐Abutment‐Crowns Versus Hybrid‐Abutments with Separate Crowns – A Laboratory Study

Abstract

Objective

The purpose of this laboratory study was to evaluate the fatigue resistance, fracture resistance and mode of failure of posterior hybrid‐abutment‐crown versus hybrid‐abutment with separate crown, both bonded to short titanium bases.

Materials and Methods

Thirty‐two titanium implants were embedded perpendicularly in auto‐polymerizing resin. Implant‐supported restorations simulating a maxillary first premolar were designed and milled using a CAD/CAM system and divided into 2 groups according to material (n=16): zirconia (Z) and lithium disilicate (L). Each group was subdivided into 2 subgroups according to design (n=8): hybrid‐abutment‐crown (ZS, LS) and hybrid‐abutment with separate crown (ZC, LC). Each group was subjected to 1.2 million cycles of thermo‐mechanical fatigue loading in a dual‐axis chewing simulator at 120 N load. Surviving specimens were subjected to quasi‐static loading in a universal testing machine. Mode of failure was determined under a low magnification optical microscope.

Results

During chewing simulation, 18.8% of zirconia and 43.8% of lithium disilicate restorations failed. The fracture resistance median values ranged from 3730 N for group ZC, 3400 N for group ZS, 1295 N for group LS to 849 N for group LC. Group ZC had a statistically significant higher fracture resistance than groups LC and LS, however it did not differ significantly from group ZS (P ≤ 0.05). Failures were seen in both titanium bases and ceramic superstructure.

Conclusions

Zirconia and lithium disilicate hybrid implant‐supported restorations with short (3 mm) titanium bases failed in a considerable number already during chewing simulation. Therefore, despite their high fracture strength the use in the posterior region should be considered critically.

This article is protected by copyright. All rights reserved.

from OroFacial via a.sfakia on Inoreader https://ift.tt/2RFcg8U

Surface modification of ultrafine‐grained titanium: influence on mechanical properties, cytocompatibility and osseointegration potential

Abstract

Objective

The main objective of this study was to demonstrate that dental implants made from ultrafine‐grain titanium (UFG‐Ti) can be created that replicate state of the art surfaces of standard coarse‐grain titanium (Ti), showing excellent cytocompatibility and osseointegration potential while also providing improved mechanical properties.

Material and methods

UFG‐Ti was prepared by continuous equal channel angular processing (ECAP) and surfaces were treated by sand‐blasting and acid‐etching. Mechanical properties (tensile and fatigue strength), wettability and roughness parameters were evaluated. Human trabecular bone‐derived osteoblast precursor cells (HBCs) were cultured on all samples to examine cytocompatibility and mineralization after 4 and 28 days, respectively. Biomechanical pull‐out measurements were performed in a rabbit in vivo model 4 weeks after implantation.

Results

Both yield and tensile strength as well as fatigue endurance were higher for UFG‐Ti compared to Ti by 40%, 45% and 34%, respectively. Fatigue endurance was slightly reduced following surface treatment. Existing surface treatment protocols could be applied to UFG‐Ti and resulted in similar roughness and wettability as for standard Ti. Cell attachment and spreading was comparable on all samples, but mineralization was higher for the surfaces with hydrophilic treatment with no significant difference between UFG‐Ti and Ti. Pull‐out tests revealed that osseointegration of surface treated UFG‐Ti was found to be similar to that of surface treated Ti.

Conclusion

It could be demonstrated that existing surface treatments for Ti can be translated to UFG‐Ti and furthermore, that dental implants made from surface‐treated UFG‐Ti exhibit superior mechanical properties while maintaining cytocompatibility and osseointegration potential.

This article is protected by copyright. All rights reserved.

from OroFacial via a.sfakia on Inoreader https://ift.tt/2QiW28F

Perceptions and experiences of patients following treatment with single‐implant mandibular overdentures: a qualitative study

Abstract

Objective

This study aimed to explore the perceptions and long‐term experiences of edentulous patients rehabilitated with single‐implant mandibular overdentures (SIMO).

Methods

Thirteen participants, mean age 65.7 years, 69.2% women, who had had their treatment completed for at least 1 year, were invited and included in the study. Focus groups including four to five participants each, were conducted, audio and video recorded and transcribed verbatim. Subsequently, the transcripts were analysed according to the principles of thematic analysis.

Results

Four major themes emerged: before decision to undergo treatment with SIMO, implant surgery experience, perception of treatment outcomes, and impressions about the care received. Lack of information, cost, comorbidities, older age and fear were initial barriers to the decision for treatment. Dissatisfaction with previous treatment and a sense of opportunity motivated the decision. There were ambivalent reports of absence of pain during surgery and discomfort during anaesthesia. Post‐surgical recovery exceeded the pre‐surgical negative expectations in most cases. There was a tendency for a positive impact of SIMO on the patients' quality of life, comprising improved ability to chew and communicate, dietary diversification, greater comfort and safety, increased self‐confidence and social interaction. Few minor inconveniences were reported: insecurity after an episode of denture fracture, and the need to use adhesive paste. Satisfaction with the care received and the trust in the dentist and dental team were evident.

Conclusion

In general, participants presented positive perceptions and rewarding experiences after rehabilitation with SIMO.

This article is protected by copyright. All rights reserved.

from OroFacial via a.sfakia on Inoreader https://ift.tt/2RRrvve

Titanium dioxide and modified titanium dioxide by silver nanoparticles as an anti biofilm filler content for composite resins

Publication date: Available online 7 December 2018

Source: Dental Materials

Author(s): Hércules Bezerra Dias, Maria Inês Basso Bernardi, Taís Maria Bauab, Antônio Carlos Hernandes, Alessandra Nara de Souza Rastelli

Abstract

Objective

The aim of this study was to evaluate the antibacterial activity of a composite resin modified by TiO₂ and TiO₂/Ag nanoparticles and their influence over different properties.

Methods

TiO₂ and TiO₂/Ag NPs were synthesized by polymeric precursor and microwave-assisted hydrothermal methods and then, characterized by different techniques. Direct contact test was performed using Filtek™ Z350XT blended with 0.5; 1 and 2% (wt.) of NPs against Streptococcus mutans to determine the best concentration to the other tests. After that, the modified composite resin was tested against S. mutans 7-day biofilm (CFU/mL). Also, compressive and diametral tensile strength (n = 40), degree of conversion (n = 25) and surface roughness (n = 50) was performed. The data were analyzed by ANOVA and Tukey's test for multiple comparison at 5% significance level.

Results

The direct contact test demonstrates that by increasing the nanoparticle content, the bacterial growth is significantly reduceed (p < 0.05). The inclusion of 2% of TiO₂/Ag NPs significantly decreased (p < 0.05) the biofilm accumulation of S. mutans on the composite resin surface compared to the control Group. The TiO₂ NPs treated with an organosilane increased compressive strength of composite resin (p < 0.05). Degree of conversion remained unchanged (p > 0.05) and the surface roughness increased with the NPs (p < 0.05), except for the TiO₂ by polymeric precursor Group (p > 0.05).

Significance

The development of an antibacterial dental restorative material that hinder S. mutans biofilm without sacrificing the mechanical and physical properties is desirable in dental material science.

from OroFacial via a.sfakia on Inoreader https://ift.tt/2PqAoKk

Polymerization shrinkage of bulk fill composite through optical coherence tomography

Publication date: Available online 8 December 2018

Source: Dental Materials

Author(s):

from OroFacial via a.sfakia on Inoreader https://ift.tt/2zMmHAE

Miniature specimens for fracture toughness evaluation of dental resin composites

Publication date: Available online 7 December 2018

Source: Dental Materials

Author(s): Herzl Chai, Xiaohong Wang, Jirun Sun

Abstract

Objective

Millimeter-scale ("miniature") specimens enable in-situ evaluation of mechanical properties of engineering materials at reduced cost. Here three such specimens for measuring fracture toughness (K_C) are developed and implemented to new dental materials. The latter include concurrent methacrylate-based and new ether-based resin composites designed to reduce polymerization stress and enhance service life in restored teeth.

Methods

Fracture toughness of four experimental and one commercial dental resin composites are evaluated using three-point bending (3PB), wedge double-cantilever-beam (WDCD) and edge chipping miniature test specimens. The values of K_C were compared with those obtained following ISO standard method ISO6872: 2014. The stress intensity factor (K) for the 3PB and WDCB specimens was determined using linear fracture mechanics analyses made in conjunction with the Finite Element technique, with due consideration given to the finite width of pre-crack.

Results

Analytic expressions for predicting K_C were developed for all three miniature specimens. The width of pre-crack, generally neglected for conventional specimens, significantly affect K. Measured K_C conclusively agree with those of commercial or well-studied materials as obtained using conventional specimens, with error bounded by 5–10 percent.

Significance

The edge chipping test was successfully applied for the first time to non-brittle materials like dental resin composites. The miniature specimens developed will expedite the evaluation of fracture toughness of dental resin composites by saving materials and provide needed in-situ assessment capability. The chipping test which requires no introduction of initial crack and involves no use of elastic constants is especially suitable to functionally graded materials and in-situ study of restored teeth. The WDCB specimen enables stable crack growth, a useful trait in fatigue studies.

Graphical abstract

from OroFacial via a.sfakia on Inoreader https://ift.tt/2Pr31Hx

In memoriam of Professor Michael Braden: 6th September 1928–22nd November 2017

Publication date: Available online 7 December 2018

Source: Dental Materials

Author(s): Mangala P. Patel, Sandra Parker

from OroFacial via a.sfakia on Inoreader https://ift.tt/2zMmAVK

Synergistic effects of VE-TPGS and riboflavin in crosslinking of dentine

Publication date: Available online 7 December 2018

Source: Dental Materials

Author(s): U. Daood, J.P. Matinlinna, A.S. Fawzy

Abstract

Objective

Effect of d-alpha-tocopheryl poly(ethyleneglycol)-1000-succinate (VE-TPGS) with riboflavin-5′-phosphate solution on crosslinking of dentine collagen was investigated to analyze collagen's structural integrity.

Methods

VE-TPGS was added to RF-solution, at RF/VE-TPGS (w/w) ratios of 0.125/0.250 and 0.125/0.500. Demineralized dentine beams were used (10 wt.% phosphoric acid), rinsed using deionized-water and analysed using ELISA (Human MMP2 ELISA; Human CTSK/Cathepsin-K for MMP2 and Cathepsin K analysis). AFM of dentine collagen-fibrils structure was done before and after dentine specimens' placement in mineralization solution and tested after 14 days in artificial saliva/collagenase (AS/Co) solution. The specimens were tested after 24 h in mineralization solution for surface/bulk elastic modulus. Nano-indentation was carried out for each specimen on intertubular-dentine with lateral spacing of 400 nm. Reduced elastic-modulus and nano-hardness were calculated and collagen content was determined using hydroxyproline-assay. Micro-Raman were performed. TEM was carried out to study structural variations of dentine-collagen in artificial-saliva (collagenase). Data were presented as mean ± standard deviation and analyzed by SPSS v.15, by analysis of variance.

Results

Synergetic effect of VE-TPGS was observed with RF through higher structural integrity of dentine collagen-fibrils shown by TEM/AFM. Superior surface/bulk mechanical stability was shown by nano-indentation/mechanical testing. Improvement in collagenase degradation resistance for hydroxyproline release was observed and lower endogenous-protease release of MMP-2/Cathepsin-K. Raman-analysis analysed chemical interactions between RF and collagen confirming structural-integrity of collagen fibrils after crosslinking. After 24 h mineralization, AFM showed mineral depositions in close association with dentine-collagen fibrils with RF/VE-TPGS formulations.

Significance

Potential synergetic effect of RF/VE-TPGS was observed by reflection of higher structural integrity and conformational-stability of dentine-collagen fibrils.

from OroFacial via a.sfakia on Inoreader https://ift.tt/2zQaKKh

Validity and Reliability of the Turkish SingingVoice Handicap Index-10

Publication date: Available online 8 December 2018

Source: Journal of Voice

Author(s): Fatma Esen Aydinli, Sevtap Akbulut, Esra Özcebe, Oğuz Kuşçu, Taner Yilmaz, Clark A. Rosen, Jackie Gardner-Schmidt

Summary

Objective

To evaluate the validity and reliability of the Turkish version of the Singing Voice Handicap Index-10 (SVHI-10).

Study Design

Cross-sectional study.

Methods

Two hundred singers consisting of a control group (n = 136) without voice complaints and a study group (n = 64) diagnosed with a voice disorder served as participants. To detect test-retest reliability, 97 participants (representing a portion of both the control and study group participants) completed the index twice with a minimum of a one-week interval between each completion. Internal consistency was confirmed using Cronbach's alpha coefficient. To complete a clinical validity assessment, scores from the control group participants were compared with scores from the study group participants. To determine content validity, the correlation between the SVHI-10 and the participants' perceptions of singing voice complaints was researched. The sensitivity and specificity of the SVHI-10/Turkish version were calculated using a receiver operating characteristic curve analysis.

Results

Cronbach's alpha coefficient, which was equal to 0.91, proved to have excellent internal consistency. Item-total correlations were found in the range of 0.55 to 0.76. The mean SVHI-10/Turkish score for the control group was 8.14 ± 5.4, whereas this value was significantly higher in the study group (20.54 ± 6.9, P < 0.001). The Pearson product-moment correlation test indicated that the Turkish SVHI-10 is a reliable tool (r = 0.90, n = 97, P < 0.001). The area under curve of the Turkish SVHI-10 was 0.95. The optimal cut-off point was found to be 11.5, with a sensitivity of 95.8% and a specificity of 83.2%.

Conclusions

The Turkish version of the SVHI-10 has proven to be a reliable and valid instrument for evaluating the self-perception of a singer in relation to voice problems. It can also be used as a quick screening tool because a score on the SVHI-10 higher than 11.5 is indicative of an abnormal singer's perceived voice handicap.

from Speech via a.sfakia on Inoreader https://ift.tt/2ElyWYx

Comparison of Maximum Oxygen Uptake and Rating Perceived Exertion in Woman's Kabaddi Athletes (Without Breathy Voice to Severe Breathy Voice)

Publication date: Available online 7 December 2018

Source: Journal of Voice

Author(s): Samaneh Ebrahimi, Mandana Gholami

Summary

Objective

There is limited research on voice problems of athletes, especially Kabaddi athletes who use their voice during Kabaddi exercises and may damage their vocal folds and impair their voice quality. The present study aimed to compare maximum oxygen uptake (VO₂max) and rating perceived exertion (RPE) in Woman's Kabaddi athletes without breathy voice (BV) to severe BV.

Materials and Methods

Seventy woman's Kabaddi athletes (mean age of 20.5 ± 2.7 years, height of 163 ± 3.6 cm, weight of 61.4 ± 5.4 kg) at the club and national team level (without BV to severe BV) were compared in this study. Data were collected by imaging the larynx by a stroboscopic device (there is gap and asymmetry between vocal folds, presence of mass on vocal folds, muscle tension dysphonia, hoarseness, and harshness), evaluating the voice parameters by Vocal Assessment software (mean F₀ (Hz), F₀SD (Hz), jitter (%), shimmer (%), Normal Noise Energy (NNE) (dB)), and calculating VO₂max by Bruce treadmill test. RPE was calculated by a 15-point (6–20) Borg test.

Results

The results showed that 39 (55.17%) subjects had moderate and high BV symptoms and 31 (44.28%) had no symptoms of BV and low BV. The mean fundamental frequency in the group with moderate and severe BV was equal to 2.59 Hz opposite the mean fundamental frequency in the group without BV and low BV was equal to 0.65 Hz, and in contrast, the jitter (0.47%) opposite (0.19%) and the shimmer was equal to (6.64%) opposite (0.67%) and the NNE was equal to (−3.08 dB) In front of (−11.95 dB). There was no significant difference between VO2max in two groups of Woman's Kabaddi athletes as well as RPE in two groups of Woman's Kabaddi athletes at significant level of P ≤ 0.05.

Conclusions

Severe BV is affected by voice abuse. Voice abuse during Kabaddi is negatively affecting the quality of voice. After Kabaddi sport, athletes are complained from obstruction, hoarseness, and harshness due to disturbances in vocal folds and throat dryness. According to the data obtained from this study, abuse has a negative effect on vocal folds, which is followed by BV in various degrees in Kabaddi athletes.

from Speech via a.sfakia on Inoreader https://ift.tt/2E7MTsh

Transcutaneous Electrical Nerve Stimulation Combined With Voice Therapy in Women With Muscle Tension Dysphonia

Publication date: Available online 7 December 2018

Source: Journal of Voice

Author(s): Banafshe Mansuri, Farhad Torabinejhad, Ali Ashraf Jamshidi, Payman Dabirmoghaddam, Behnoosh Vasaghi-Gharamaleki, Leila Ghelichi

Summary

Objectives

The purpose of the present study was to investigate the effect of Voice Therapy (VT) with and without Transcutaneous Electrical Nerve Stimulation (TENS) in women with Muscle Tension Dysphonia (MTD).

Methods

A total of 20 women with MTD participated in the study. Participants underwent evaluation of auditory-perceptual assessment, acoustic voice analysis, Vocal Tract Discomfort (VTD), and musculoskeletal pain before and after the treatment. The participants were divided into two groups: (1) TENS + VT group (10 participants) and (2) VT group (10 participants). Both groups received 10 sessions of treatment, twice a week, each lasting 50 minutes. The statistical analysis was performed using Wilcoxon signed ranked and Mann-Whitney U tests (P < 0.05).

Results

After VT, significant improvements were observed in all auditory-perceptual parameters and all VTD items except for the tickling frequency and severity. The VT caused significant reduction in the frequency of pain in anterior neck, posterior neck, and the larynx. Also, VT resulted in a significant reduction in pain intensity only in the larynx. After VT + TENS, significant improvements were observed in all auditory-perceptual parameters, shimmer, and all VTD items. Moreover, the VT + TENS led to a significant decrease in the frequency and intensity of pain in anterior neck, posterior neck, the larynx, masseters, shoulders, and upper back. The findings of between-group comparison after treatment showed significantly more reduction in the frequency (dry and pain items) and severity (tight and pain items) of the VTD in VT + TENS group compared with VT group. Regarding the musculoskeletal pain, significantly more reduction in the frequency and intensity of pain in anterior neck and the larynx was observed in VT + TENS group compared with VT group.

Conclusions

The VT and VT + TENS could lead to positive outcomes in auditory perceptual assessment, acoustic voice analysis, the VTD, and assessment of musculoskeletal pain. In some items of frequency and severity of VTD scale and assessment of musculoskeletal pain, VT + TENS also produced better results compared with VT. As a result, TENS was recommended as a complementary therapy for patients with MTD, especially when these patients had more complaints about VTD and musculoskeletal pain.

from Speech via a.sfakia on Inoreader https://ift.tt/2Emr613

Pharmacogenetics of angiotensin converting enzyme inhibitor ‐ induced angioedema

Abstract

Angioedema is a rare adverse effect of the commonly used angiotensin converting enzyme inhibitors (ACEi) and is reported to occur with a prevalence of 0.1 – 0.7%. Although most ACEi‐induced angioedema (ACEi‐A) cases are mild, severe cases requiring intensive care and even resulting in death have been reported in the literature. The mechanisms underlying ACEi–A are not yet fully understood, but bradykinin and/or substance P accumulation resulting from inhibition of ACE, is believed to play a crucial role. ACEi‐A occurs at variable frequencies across different racial groups, suggesting a genetic association to the development of ACEi‐A. To date, one genome wide association study and several candidate gene studies have been published on the association of genetic variation with ACEi‐A. Genetic associations reported have been attributed to several distinct mechanisms: (1) genes coding for alternative enzymes responsible for the degradation of bradykinin and/or substance P in the diminution of ACE activity (2) ACE gene function, (3) bradykinin receptor genes, (4) genes implicated in immune and inflammation regulation, and (5) genes in the fibrinolytic and coagulation pathway. Despite several plausible genetic associations, there are currently no genetic variants with sufficient effect to be clinically useful. The low incidence of ACEi‐A suggests that a combination of genomic approaches with the capability to detect potentially important variants might be required to shed light on the mechanism of this adverse reaction. Additionally, many non‐genetic risk factors associated with ACEi‐A suggest the potential contribution of epigenetic dysregulation.

This article is protected by copyright. All rights reserved.

from Allergy and Immunology via a.sfakia on Inoreader https://ift.tt/2EchZii

A Deep Learning Framework for Unsupervised Affine and Deformable Image Registration

Publication date: Available online 8 December 2018

Source: Medical Image Analysis

Author(s): Bob D. de Vos, Floris F. Berendsen, Max A. Viergever, Hessam Sokooti, Marius Staring, Ivana Išgum

Abstract

Image registration, the process of aligning two or more images, is the core technique of many (semi-)automatic medical image analysis tasks. Recent studies have shown that deep learning methods, notably convolutional neural networks (ConvNets), can be used for image registration. Thus far training of ConvNets for registration was supervised using predefined example registrations. However, obtaining example registrations is not trivial. To circumvent the need for predefined examples, and thereby to increase convenience of training ConvNets for image registration, we propose the Deep Learning Image Registration (DLIR) framework for unsupervised affine and deformable image registration. In the DLIR framework ConvNets are trained for image registration by exploiting image similarity analogous to conventional intensity-based image registration. After a ConvNet has been trained with the DLIR framework, it can be used to register pairs of unseen images in one shot. We propose flexible ConvNets designs for affine image registration and for deformable image registration. By stacking multiple of these ConvNets into a larger architecture, we are able to perform coarse-to-fine image registration. We show for registration of cardiac cine MRI and registration of chest CT that performance of the DLIR framework is comparable to conventional image registration while being several orders of magnitude faster.

Graphical abstract

from Imaging via a.sfakia on Inoreader https://ift.tt/2QmewFa

Predicting development of sustained unresponsiveness to milk oral immunotherapy using epitope-specific antibody binding profiles

Publication date: Available online 7 December 2018

Source: Journal of Allergy and Clinical Immunology

Author(s): Mayte Suárez-Fariñas, Maria Suprun, Helena L. Chang, Gustavo Gimenez, Galina Grishina, Robert Getts, Kari Nadeau, Robert A. Wood, Hugh A. Sampson

Background

In a recent trial of milk oral immunotherapy (MOIT) with or without omalizumab in 55 patients with milk allergy treated for 28 months, 44 of 55 subjects passed a 10-g desensitization milk protein challenge; 23 of 55 subjects passed the 10-g sustained unresponsiveness (SU) challenge 8 weeks after discontinuing MOIT.

Objective

We sought to determine whether IgE and IgG₄ antibody binding to allergenic milk protein epitopes changes with MOIT and whether this could predict the development of SU.

Methods

By using a novel high-throughput Luminex-based assay to quantitate IgE and IgG₄ antibody binding to 66 sequential epitopes on 5 milk proteins, serum samples from 47 subjects were evaluated before and after MOIT. Machine learning strategies were used to predict whether a subject would have SU after 8 weeks of MOIT discontinuation.

Results

MOIT profoundly altered IgE and IgG₄ binding to epitopes, regardless of treatment outcome. At the initiation of MOIT, subjects achieving SU exhibited significantly less antibody binding to 40 allergenic epitopes than subjects who were desensitized only (false discovery rate ≤ 0.05 and fold change > 1.5). Based on baseline epitope-specific antibody binding, we developed predictive models of SU. Using simulations, we show that, on average, IgE-binding epitopes alone perform significantly better than models using standard serum component proteins (average area under the curve, >97% vs 80%). The optimum model using 6 IgE-binding epitopes achieved a 95% area under the curve and 87% accuracy.

Conclusion

Despite the relatively small sample size, we have shown that by measuring the epitope repertoire, we can build reliable models to predict the probability of SU after MOIT. Baseline epitope profiles appear more predictive of MOIT response than those based on serum component proteins.

Graphical abstract

from Allergy and Immunology via a.sfakia on Inoreader https://ift.tt/2SBgoGO

Late thymic deficiency after HLA-haploidentical hematopoietic stem cell transplantation for severe combined immunodeficiency

Publication date: Available online 7 December 2018

Source: Journal of Allergy and Clinical Immunology

Author(s): Markus J. Ege, Catharina Schuetz, Eva-Maria Jacobsen, Susanna M. Müller-Langer, Ingrid Furlan, Mehtap Sirin, Ulrich Pannicke, Klaus Schwarz, Klaus-Michael Debatin, Manfred Hönig, Ansgar Schulz, Wilhelm Friedrich

from Allergy and Immunology via a.sfakia on Inoreader https://ift.tt/2Synpbq

Intravenous immunoglobulin induces IL-4 in human basophils by signaling through surface-bound IgE

Publication date: Available online 7 December 2018

Source: Journal of Allergy and Clinical Immunology

Author(s): Caroline Galeotti, Emmanuel Stephen-Victor, Anupama Karnam, Mrinmoy Das, Laurent Gilardin, Mohan S. Maddur, Sandra Wymann, Cédric Vonarburg, Alain Chevailler, Jordan D. Dimitrov, Olivier Benveniste, Pierre Bruhns, Srini V. Kaveri, Jagadeesh Bayry

Abstract

Background

Therapeutic normal immunoglobulin G or intravenous immunoglobulin (IVIG) exerts anti-inflammatory effects via several mutually nonexclusive mechanisms. Recent data in mouse models of autoimmune diseases suggest that IVIG induces IL-4 in basophils by enhancing IL-33 in SIGN-R1⁺ innate cells. However, translational insight on these data is lacking.

Objective

We sought to investigate the effect of IVIG on human basophil functions.

Methods

Isolated circulating basophils from the healthy donors were cultured in the presence of IL-3, IL-33, GM-CSF, TSLP or IL-25. The effect of IVIG, F(ab')₂ and Fc fragments of IVIG was examined on the expression of various surface molecules, phosphorylation of Syk, induction of cytokines, and histamine release. Phenotype of basophils was also analyzed from IVIG-treated myopathy patients. Approaches such as depletion of anti-IgE-reactivity from IVIG, blocking antibodies or inhibitors were used to investigate the mechanisms.

Results

We report that IVIG directly induces activation of IL-3-primed human basophils, but IL-33 and other cytokines were dispensable for this effect. The activation of basophils by IVIG led to enhanced expression of CD69 and secretion of IL-4, IL-6 and IL-8. IVIG-treated myopathy patients displayed enhanced expression of CD69 on the basophils. Syk pathway is implicated in these functions of IVIG and were mediated via F(ab')₂ fragments. Mechanistically, IVIG induced IL-4 in human basophils by interacting with basophil surface-bound IgE but independent of FcγRII, type II Fc receptors, C-type lectin receptors and Siglecs.

Conclusion

These results uncovered a pathway of promoting Th2 response by IVIG through direct interaction of IgG with human basophils.

Graphical abstract

from Allergy and Immunology via a.sfakia on Inoreader https://ift.tt/2QDmHfX

Antibiotic choice and MRSA rate in children who are hospitalized for atopic dermatitis

Publication date: Available online 7 December 2018

Source: Annals of Allergy, Asthma & Immunology

Author(s): Vivian Wang, Matthew Keefer, Peck Y. Ong

from Allergy and Immunology via a.sfakia on Inoreader https://ift.tt/2E68O38

Successful treatment of four types of chronic urticaria with anti-IgE omalizumab in the same patient

Publication date: Available online 7 December 2018

Source: Annals of Allergy, Asthma & Immunology

Author(s): Eustachio Nettis, Elisabetta Di Leo, Gianfranco Calogiuri, Caterina Foti, Luigi Macchia

from Allergy and Immunology via a.sfakia on Inoreader https://ift.tt/2EiRKYt

Development of oral sensory-motor functions of preterm and low-birth-weight newborns under speech-language pathology care

Publication date: Available online 7 December 2018

Source: Revista de Logopedia, Foniatría y Audiología

Author(s): Flaviana de Souza Cardoso, Danielle Xavier Pereira, Dyego Leandro Bezerra de Souza, Renata Veiga Andersen Cavalcanti

Abstract

Introduction

Preterm and low-birth-weight newborns may present immaturity in the functions of sucking, swallowing and breathing, speech therapists inserted in the hospital focus on the development of newborns' oral sensorimotor system, promoting a safe transition from tube feeding to breastfeeding and contributing to improving the quality of life of the child population. The present study aimed to analyze the development of oral functions, oral feeding transition time and breastfeeding of preterm and low-birth-weight newborns under Speech-Language Pathology care.

Methods

A prognostic study carried out at a maternity hospital, based on the data collected from 121 filed medical records of newborns attended between September 2015 to July 2017. The Kaplan–Meier method, the Log Rank test and the Pearson correlation test were used for data analysis, considering a significance level of 0.05 (95%).

Results

It was observed that the lower the gestational age and the birth weight of newborns, the more speech therapy services were required until the establishment of exclusive OF; also, the transition time and the average time of using the orogastric tube were inversely proportional to the gestational age at birth. The non-nutritive sucking technique was the most used for stimulation, and 78.5% of the NBs were discharged from the hospital on exclusive breastfeeding.

Conclusion

Moderate to late preterm and low-birth-weight newborns are able to more quickly acquire the oral sensorimotor system functional pattern, and there are indications that Speech-Language Pathology care reduces the transition time to oral feeding, thus increasing the success rate of exclusive breastfeeding.

Resumen

Introducción

Los recién nacidos (RN) prematuros y con bajo peso pueden presentar inmadurez en las funciones de succión, deglución y respiración. Los logopedas en los hospitales trabajan el desarrollo del sistema sensoriomotor oral de los RN, promoviendo una transición segura de la sonda a la lactancia materna, lo que contribuye a mejorar la calidad de vida de la población infantil. El objetivo del presente estudio era analizar el desarrollo de las funciones orales, el tiempo de transición a la alimentación por vía oral (VO) y la lactancia materna de los RN prematuros, y con bajo peso al nacer bajo el cuidado fonoaudiológico.

Métodos

Este estudio de pronóstico se llevó a cabo en una maternidad, con base en la recopilación de datos en prontuarios archivados de 121 RN atendidos entre septiembre de 2015 y julio de 2017. En el análisis de los datos se aplicó el método de Kaplan-Meier, el test log-rank y la prueba de correlación de Pearson. Se consideró un nivel de significancia de 0,05 (95%).

Resultados

Se observó que cuanto menores eran la edad gestacional y el peso de nacimiento del RN, más necesidad de servicios fonoaudiológicos había hasta el establecimiento de la VO exclusiva, y el tiempo de transición y el tiempo promedio de utilización de la sonda orogástrica eran inversamente proporcionales a la edad gestacional al nacimiento. La técnica de succión no nutritiva fue la más utilizada para la estimulación, y el 78,5% de los RN recibieron el alta hospitalaria con lactancia exclusiva.

Conclusión

Los RN prematuros de moderados a tardíos y de bajo peso son capaces de adquirir el patrón funcional del sistema sensoriomotor oral con mayor rapidez, y hay indicios de que la atención fonoaudiológica reduce el tiempo de transición alimentaria a la VO, y aumenta la tasa de éxito de lactancia materna exclusiva.

from Speech via a.sfakia on Inoreader https://ift.tt/2B59t1p

Impact of Effective Detector Pixel and CT Voxel Size on Accurate Estimation of Blood Volume in Opacified Microvasculature

Publication date: Available online 7 December 2018

Source: Academic Radiology

Author(s): Mahya Sheikhzadeh, Andrew J Vercnocke, Shengzhen Tao, Kishore Rajendran, Shuai Leng, Erik L Ritman, Cynthia H. McCollough

Rationale and Objectives

The purpose of this study was to determine the impact of effective detector-pixel-size and image voxel size on the accurate estimation of microvessel density (ratio of microvascular lumen volume/tissue volume) in an excised porcine myocardium specimen using microcomputed tomography (CT), and the ability of whole-body energy-integrating-detector (EID) CT and photon-counting-detector (PCD) CT to measure microvessel density in the same ex vivo specimen.

Materials and Methods

Porcine myocardial tissue in which the microvessels contained radio-opaque material was scanned using a micro-CT scanner and data were generated with a range of detector pixel sizes and image voxel sizes from 20 to 260 microns, to determine the impact of these parameters on the accuracy of microvessel density estimates. The same specimen was scanned in a whole-body EID CT and PCD CT system and images reconstructed with 600 and 250 micron slice thicknesses, respectively. Fraction of tissue volume that is filled with opacified microvessels was determined by first subtracting the mean background attenuation value from all voxels, and then by summing the remaining attenuation.

Results

Microvessel density data were normalized to the value measured at 20 µm voxel size, which was considered reference truth for this study. For emulated micro-CT voxels up to 260 µm, the microvessel density was underestimated by at most 11%. For whole-body EID CT and PCD CT, microvessel density was underestimated by 9.5% and overestimated by 0.1%, respectively.

Conclusion

Our data indicate that microvessel density can be accurately calculated from the larger detector pixels used in clinical CT scanners by measuring the increase of CT attenuation caused by these opacified microvessels.

from Imaging via a.sfakia on Inoreader https://ift.tt/2Qjm2AF

Tonic thermonociceptive stimulation selectively modulates ongoing neural oscillations in the human posterior insula: Evidence from intracerebral EEG

Publication date: Available online 5 December 2018

Source: NeuroImage

Author(s): Giulia Liberati, Maxime Algoet, Susana Ferrao Santos, Jose Geraldo Ribeiro-Vaz, Christian Raftopoulos, André Mouraux

Abstract

The human insula is an important target for spinothalamic input, but there is still no consensus on its role in pain perception and nociception. In this study, we show that the human insula exhibits activity preferential for sustained thermonociception. Using intracerebral EEG recorded from the insula of 8 patients (2 females) undergoing a presurgical evaluation of focal epilepsy (53 contacts: 27 anterior, 26 posterior), we "frequency-tagged" the insular activity elicited by sustained thermonociceptive and vibrotactile stimuli, by periodically modulating stimulation intensity at a fixed frequency of 0.2 Hz during 75 s. Both types of stimuli elicited an insular response at the frequency of stimulation (0.2 Hz) and its harmonics, whose magnitude was significantly greater in the posterior insula compared to the anterior insula. Compared to vibrotactile stimulation, thermonociceptive stimulation exerted a markedly greater 0.2 Hz modulation of ongoing theta-band (4–8 Hz) and alpha-band (8–12 Hz) oscillations. These modulations were also more prominent in the posterior insula compared to the anterior insula. The identification of oscillatory activities preferential for thermonociception could lead to new insights into the physiological mechanisms of nociception and pain perception in humans.

from Imaging via a.sfakia on Inoreader https://ift.tt/2QDe1pT

Freely chosen and instructed actions are terminated by different neural mechanisms revealed by kinematics-informed EEG

Publication date: March 2019

Source: NeuroImage, Volume 188

Author(s): Shivakumar Viswanathan, Bin A. Wang, Rouhollah O. Abdollahi, Silvia Daun, Christian Grefkes, Gereon R. Fink

Abstract

Neurophysiological accounts of human volition are dominated by debates on the origin of voluntary choices but the neural consequences that follow such choices remain poorly understood. For instance, could one predict whether or not an action was chosen voluntarily based only on how that action is motorically executed? We investigated this possibility by integrating scalp electroencephalograms and index-finger accelerometer recordings acquired while people chose between pressing a left or right button either freely or as instructed by a visual cue. Even though freely selected and instructed actions were executed with equal vigor, the timing of the movement to release the button was comparatively delayed for freely selected actions. This chronometric difference was six-times larger for the β-oscillations over the sensorimotor cortex that characteristically accompany an action's termination. This surprising modulation of an action's termination by volition was traceable to volition-modulated differences in how the competing yet non-selected action was represented and regulated.

from Imaging via a.sfakia on Inoreader https://ift.tt/2QFdjYX

BOLD hemodynamic response function changes significantly with healthy aging

Publication date: Available online 6 December 2018

Source: NeuroImage

Author(s): Kathryn L. West, Mark D. Zuppichini, Monroe P. Turner, Dinesh K. Sivakolundu, Yuguang Zhao, Dema Abdelkarim, Jeffrey S. Spence, Bart Rypma

Abstract

Functional magnetic resonance imaging (fMRI) has been used to infer age-differences in neural activity from the hemodynamic response function (HRF) that characterizes the blood-oxygen-level-dependent (BOLD) signal over time. BOLD literature in healthy aging lacks consensus in age-related HRF changes, the nature of those changes, and their implications for measurement of age differences in brain function. Between-study discrepancies could be due to small sample sizes, analysis techniques, and/or physiologic mechanisms. We hypothesize that, with large sample sizes and minimal analysis assumptions, age-related changes in HRF parameters could reflect alterations in one or more components of the neural-vascular coupling system. To assess HRF changes in healthy aging, we analyzed the large population-derived dataset from the Cambridge Center for Aging and Neuroscience (CamCAN) study (Shafto et al., 2014). During scanning, 74 younger (18–30 years of age) and 173 older participants (54–74 years of age) viewed two checkerboards to the left and right of a central fixation point, simultaneously heard a binaural tone, and responded via right index finger button-press. To assess differences in the shape of the HRF between younger and older groups, HRFs were estimated using FMRIB's Linear Optimal Basis Sets (FLOBS) to minimize a priori shape assumptions. Group mean HRFs were different between younger and older groups in auditory, visual, and motor cortices. Specifically, we observed increased time-to-peak and decreased peak amplitude in older compared to younger adults in auditory, visual, and motor cortices. Changes in the shape and timing of the HRF in healthy aging, in the absence of performance differences, support our hypothesis of age-related changes in the neural-vascular coupling system beyond neural activity alone. More precise interpretations of HRF age-differences can be formulated once these physiologic factors are disentangled and measured separately.

from Imaging via a.sfakia on Inoreader https://ift.tt/2QLvPze

Olfactory loss is associated with reduced hippocampal activation in response to emotional pictures

Publication date: Available online 5 December 2018

Source: NeuroImage

Author(s): Pengfei Han, Thomas Hummel, Claudia Raue, Ilona Croy

Abstract

Emotional processing evolved within brain structures that were originally dedicated to olfactory function. Reduced olfactory function, absence of the olfactory bulb and the experimental removal of the olfactory bulb are associated with depressive behavior. Against this background, we hypothesized that olfactory dysfunction modifies the neural processing of non-olfactory emotion information. Using a functional magnetic resonance imaging design, we therefore tested whether people with and without impaired olfactory function differ in emotional perception and processing. Neural activity of 17 patients with acquired olfactory loss and 23 age- and sex-matched control participants was monitored in the MRI scanner, while they were presented with emotional and neutral pictures. Participants rated the valence and arousal for each picture after scanning. Patients showed reduced right hippocampal brain responses to emotional but not neutral pictures independent of their depressive symptoms. In addition, emotion-dependent activation in the hippocampus and insula was positively associated to the olfactory bulb (OB) volumes in healthy participants. Taken together, these findings suggest a disrupted neural processing of emotional pictures among patients with olfactory loss. This indicates a significant role of the neural olfactory trajectories for general emotion processing. Central emotion processing is reduced in olfactory disorders and relates to the OB volume in normosmic individuals.

from Imaging via a.sfakia on Inoreader https://ift.tt/2QJxo0k

Volitional modulation of higher-order visual cortex alters human perception

Publication date: Available online 4 December 2018

Source: NeuroImage

Author(s): Jinendra Ekanayake, Gerard R. Ridgway, Joel S. Winston, Eva Feredoes, Adeel Razi, Yury Koush, Frank Scharnowski, Nikolaus Weiskopf, Geraint Rees

Abstract

Can we change our perception by controlling our brain activation? Awareness during binocular rivalry is shaped by the alternating perception of different stimuli presented separately to each monocular view. We tested the possibility of causally influencing the likelihood of a stimulus entering awareness. To do this, participants were trained with neurofeedback, using realtime functional magnetic resonance imaging (rt-fMRI), to differentially modulate activation in stimulus-selective visual cortex representing each of the monocular images. Neurofeedback training led to altered bistable perception associated with activity changes in the trained regions. The degree to which training influenced perception predicted changes in grey and white matter volumes of these regions. Short-term intensive neurofeedback training therefore sculpted the dynamics of visual awareness, with associated plasticity in the human brain.

from Imaging via a.sfakia on Inoreader https://ift.tt/2UlD9jM

Improved EEG source localization with Bayesian uncertainty modelling of unknown skull conductivity

Publication date: Available online 6 December 2018

Source: NeuroImage

Author(s): Ville Rimpiläinen, Alexandra Koulouri, Felix Lucka, Jari P. Kaipio, Carsten H. Wolters

Abstract

Electroencephalography (EEG) source imaging is an ill-posed inverse problem that requires accurate conductivity modelling of the head tissues, especially the skull. Unfortunately, the conductivity values are difficult to determine in vivo. In this paper, we show that the exact knowledge of the skull conductivity is not always necessary when the Bayesian approximation error (BAE) approach is exploited. In BAE, we first postulate a probability distribution for the skull conductivity that describes our (lack of) knowledge on its value, and model the effects of this uncertainty on EEG recordings with the help of an additive error term in the observation model. Before the Bayesian inference, the likelihood is marginalized over this error term. Thus, in the inversion we estimate only our primary unknown, the source distribution. We quantified the improvements in the source localization when the proposed Bayesian modelling was used in the presence of different skull conductivity errors and levels of measurement noise. Based on the results, BAE was able to improve the source localization accuracy, particularly when the unknown (true) skull conductivity was much lower than the expected standard conductivity value. The source locations that gained the highest improvements were shallow and originally exhibited the largest localization errors. In our case study, the benefits of BAE became negligible when the signal-to-noise ratio dropped to 20 dB.

from Imaging via a.sfakia on Inoreader https://ift.tt/2E9yCvm

Functional connectivity changes associated with fMRI neurofeedback of right inferior frontal cortex in adolescents with ADHD

Publication date: March 2019

Source: NeuroImage, Volume 188

Author(s): K. Rubia, M. Criaud, M. Wulff, A. Alegria, H. Brinson, G. Barker, D. Stahl, V. Giampietro

Abstract

Attention Deficit Hyperactivity Disorder (ADHD) is associated with poor self-control, underpinned by inferior fronto-striatal deficits. We showed previously that 18 ADHD adolescents over 11 runs of 8.5 min of real-time functional magnetic resonance neurofeedback of the right inferior frontal cortex (rIFC) progressively increased activation in 2 regions of the rIFC which was associated with clinical symptom improvement. In this study, we used functional connectivity analyses to investigate whether fMRI-Neurofeedback of rIFC resulted in dynamic functional connectivity changes in underlying neural networks.

Whole-brain seed-based functional connectivity analyses were conducted using the two clusters showing progressively increased activation in rIFC as seed regions to test for changes in functional connectivity before and after 11 fMRI-Neurofeedback runs. Furthermore, we tested whether the resulting functional connectivity changes were associated with clinical symptom improvements and whether they were specific to fMRI-Neurofeedback of rIFC when compared to a control group who had to self-regulate another region.

rIFC showed increased positive functional connectivity after relative to before fMRI-Neurofeedback with dorsal caudate and anterior cingulate and increased negative functional connectivity with regions of the default mode network (DMN) such as posterior cingulate and precuneus. Furthermore, the functional connectivity changes were correlated with clinical improvements and the functional connectivity and correlation findings were specific to the rIFC-Neurofeedback group.

The findings show for the first time that fMRI-Neurofeedback of a typically dysfunctional frontal region in ADHD adolescents leads to strengthening within fronto-cingulo-striatal networks and to weakening of functional connectivity with posterior DMN regions and that this may be underlying clinical improvement.

Graphical abstract

from Imaging via a.sfakia on Inoreader https://ift.tt/2E5V1to

Power and temporal dynamics of alpha oscillations at rest differentiate cognitive performance involving sustained and phasic cognitive control

Publication date: Available online 2 December 2018

Source: NeuroImage

Author(s): Keyvan Mahjoory, Elena Cesnaite, Friederike U. Hohlefeld, Arno Villringer, Vadim V. Nikulin

Abstract

Resting state neuronal activity in EEG/MEG recordings is primarily characterized by the presence of alpha oscillations (approx. 8–12 Hz). However, their functional significance and link to cognitive task performance remains elusive. We investigated resting state neuronal activity and its relation to task performance by assessing traditional measures of alpha activity (power and individual alpha peak frequency) and dynamic properties of the signal measured by long-range temporal correlations (LRTC). Multichannel EEG was recorded at rest in 82 healthy male adults and compared to their cognitive performance, measured by tests involving executive functions, working memory, short- and long-term memory demands. Our results showed that attention span scores positively correlated with alpha power at rest, with corresponding neuronal sources located primarily in the left-hemispheric anterior cingulate cortex, supplementary motor area, and parietal regions. Furthermore, better working memory performance was related to increased LRTC of alpha oscillations at rest in the right hemispheric fronto-parietal, temporal, and occipital regions. Our findings suggest that resting state neuronal activity may reflect properties of brain networks that are functionally relevant for cognitive task performance. While alpha power measured at rest might relate to tasks that employ sustained inhibitory control, LRTC are suggested to reflect the capacity of neuronal networks to perform tasks that require phasic attention and quick adaptation to changing task demands.

from Imaging via a.sfakia on Inoreader https://ift.tt/2rpMYQv

Manipulating and decoding subjective gaming experience during active gameplay: a multivariate, whole-brain analysis

Publication date: March 2019

Source: NeuroImage, Volume 188

Author(s): Uijong Ju, Christian Wallraven

Abstract

A large number of perceptual and cognitive processes are instantiated during active gameplay, culminating in what is termed the overall "gaming experience", which encapsulates multiple, subjective dimensions of how one feels about the game. Although some research has been conducted into the neural mechanisms underlying the gaming experience, previous studies so far have relied on commercial games that provide little control over key aspects of gameplay and also have focused only on a few individual dimensions of the gaming experience. Here, we used a custom-made, immersive driving car game in four different gameplay versions (baseline, obstacle increase, goal decrease, speed increase) to assess and modulate the subjective gameplay experience while participants underwent a fMRI scan. A multivariate correlation analysis of whole-brain neural activity with behaviorally-identified subjective gaming experience uncovered brain networks associated with different experiences, including higher-level visual processing networks, the default network, and emotional areas. These regions were in addition able to decode the four different game conditions above chance. Our results for the first time describe the full range of cortical networks that become engaged to create the subjective experience during active gameplay.

from Imaging via a.sfakia on Inoreader https://ift.tt/2E7hW7C

Dynamic functional connectivity during task performance and rest predicts individual differences in attention across studies

Publication date: March 2019

Source: NeuroImage, Volume 188

Author(s): Angus Ho Ching Fong, Kwangsun Yoo, Monica D. Rosenberg, Sheng Zhang, Chiang-Shan R. Li, Dustin Scheinost, R. Todd Constable, Marvin M. Chun

Abstract

Dynamic functional connectivity (DFC) aims to maximize resolvable information from functional brain scans by considering temporal changes in network structure. Recent work has demonstrated that static, i.e. time-invariant resting-state and task-based FC predicts individual differences in behavior, including attention. Here, we show that DFC predicts attention performance across individuals. Sliding-window FC matrices were generated from fMRI data collected during rest and attention task performance by calculating Pearson's r between every pair of nodes of a whole-brain atlas within overlapping 10–60s time segments. Next, variance in r values across windows was taken to quantify temporal variability in the strength of each connection, resulting in a DFC connectome for each individual. In a leave-one-subject-out-cross-validation approach, partial-least-square-regression (PLSR) models were then trained to predict attention task performance from DFC matrices. Predicted and observed attention scores were significantly correlated, indicating successful out-of-sample predictions across rest and task conditions. Combining DFC and static FC features numerically improves predictions over either model alone, but the improvement was not statistically significant. Moreover, dynamic and combined models generalized to two independent data sets (participants performing the Attention Network Task and the stop-signal task). Edges with significant PLSR coefficients concentrated in visual, motor, and executive-control brain networks; moreover, most of these coefficients were negative. Thus, better attention may rely on more stable, i.e. less variable, information flow between brain regions.

from Imaging via a.sfakia on Inoreader https://ift.tt/2QFYVjg

Using GPUs to accelerate computational diffusion MRI: From microstructure estimation to tractography and connectomes

Publication date: Available online 8 December 2018

Source: NeuroImage

Author(s): Moises Hernandez-Fernandez, Istvan Reguly, Saad Jbabdi, Mike Giles, Stephen Smith, Stamatios N. Sotiropoulos

Abstract

The great potential of computational diffusion MRI (dMRI) relies on indirect inference of tissue microstructure and brain connections, since modelling and tractography frameworks map diffusion measurements to neuroanatomical features. This mapping however can be computationally highly expensive, particularly given the trend of increasing dataset sizes and the complexity in biophysical modelling. Limitations on computing resources can restrict data exploration and methodology development. A step forward is to take advantage of the computational power offered by recent parallel computing architectures, especially Graphics Processing Units (GPUs). GPUs are massive parallel processors that offer trillions of floating point operations per second, and have made possible the solution of computationally-intensive scientific problems that were intractable before. However, they are not inherently suited for all problems. Here, we present two different frameworks for accelerating dMRI computations using GPUs that cover the most typical dMRI applications: a framework for performing biophysical modelling and microstructure estimation, and a second framework for performing tractography and long-range connectivity estimation. The former provides a front-end and automatically generates a GPU executable file from a user-specified biophysical model, allowing accelerated non-linear model fitting in both deterministic and stochastic ways (Bayesian inference). The latter performs probabilistic tractography, it can generate whole-brain connectomes and supports new functionality for imposing anatomical constraints, such as inherent consideration of surface meshes (GIFTI files) along with volumetric images. We validate the frameworks against well-established CPU-based implementations and we show that despite the very different challenges for parallelising these problems, a single GPU achieves better performances than 200 CPU cores thanks to our parallel designs.

from Imaging via a.sfakia on Inoreader https://ift.tt/2E9gzVV

Nutrient biomarker patterns, cognitive function, and fMRI measures of network efficiency in the aging brain

Publication date: Available online 7 December 2018

Source: NeuroImage

Author(s): Christopher E. Zwilling, Tanveer Talukdar, Marta K. Zamroziewicz, Aron K. Barbey

Abstract

A central aim of research in the psychological and brain sciences is to establish therapeutic interventions to promote healthy brain aging. Accumulating evidence indicates that diet and the many bioactive substances present in food are reasonable interventions to examine for dementia prevention. However, interdisciplinary research that applies methods from nutritional epidemiology and network neuroscience to investigate the role of nutrition in shaping functional brain network efficiency remains to be conducted. The present study therefore sought to combine methods across disciplines, applying nutrient biomarker pattern (NBP) analysis to capture the effects of plasma nutrients in combination and to examine their collective influence on measures of functional brain network efficiency (small-world propensity). We examined the contribution of NBPs to multiple indices of cognition and brain health in non-demented elders (n = 116), investigating performance on measures of general intelligence, executive function, and memory, and resting-state fMRI measures of brain network efficiency within seven intrinsic connectivity networks. Statistical moderation investigated whether nutrient biomarker patterns influenced network efficiency and cognitive outcomes. The results revealed five NBPs that were associated with enhanced cognitive performance, including biomarker patterns high in plasma: (1) ω-3 and ω-6 polyunsaturated fatty acids (PUFAs), (2) lycopene, (3) ω-3 PUFAs, (4) carotenoids, and (5) vitamins B (riboflavin, folate, B12) and D. Furthermore, three NBPs were associated with enhanced functional brain network efficiency, including biomarker patterns high in plasma: (1) ω-6 PUFAs, (2) ω-3 PUFAs, and (3) carotene. Finally, ω-3 PUFAs moderated the fronto-parietal network and general intelligence, while ω-6 PUFAs and lycopene moderated the dorsal attention network and executive function. In sum, NBPs account for a significant proportion of variance in measures of cognitive performance and functional brain network efficiency. The results motivate a multidisciplinary approach that applies methods from nutritional epidemiology (nutrient biomarker pattern analysis) and cognitive neuroscience (functional brain network efficiency) to characterize the impact of nutrition on human health, aging, and disease.

from Imaging via a.sfakia on Inoreader https://ift.tt/2QzQWo3

Changes in functional connectivity dynamics with aging: A dynamical phase synchronization approach

Publication date: Available online 7 December 2018

Source: NeuroImage

Author(s): Sou Nobukawa, Mitsuru Kikuchi, Tetsuya Takahashi

Abstract

The dynamics of the human brain network has attracted broad attention, in recognition of the concept that functional connectivity is not static, but changes its pattern over time, even in the resting state. We hypothesized that analysis of continuously captured time-varying instantaneous phase synchronization between signals from different brain regions might add another dimension to already identified network dynamics. To validate this hypothesis as an aid to elucidating the physiological mechanisms of aging, we examined time-series of instantaneous phase synchronization events in resting-state EEG activity across the brain, in healthy younger and healthy older subjects. We then characterized the temporal dynamics of phase synchronization using multiscale entropy, which quantifies the complexity of brain signal dynamics over multiple time scales. The results of surrogate analyses confirmed that the temporal dynamics of phase synchronization arise from deterministic processes in the neural network system. Group comparison showed region-specific enhanced complexity of temporal dynamics of phase synchronization in older subjects in alpha band predominantly in frontal brain regions, which was not identified by a comparative phase synchronization approach such as phase lag index. Enhanced complexity of temporal dynamics of functional connectivity in older subjects might reflect a general network alteration theory in aging. This is a first report describing the importance of capturing the dynamics of instantaneous phase synchronization and characterizing its temporal organization. Applying this method to neurophysiologic data may provide a novel understanding of dynamical neural network processes in both healthy and pathological conditions.

from Imaging via a.sfakia on Inoreader https://ift.tt/2E7hVAA

Relationship of critical dynamics, functional connectivity, and states of consciousness in large-scale human brain networks

Publication date: Available online 6 December 2018

Source: NeuroImage

Author(s): Heonsoo Lee, Daniel Golkowski, Denis Jordan, Sebastian Berger, Rüdiger Ilg, Joseph Lee, George A. Mashour, UnCheol Lee, Michael S. Avidan, Stefanie Blain-Moraes, Goodarz Golmirzaie, Randall Hardie, Rosemary Hogg, Ellen Janke, Max B. Kelz, Kaitlyn Maier, George A. Mashour, Hannah Maybrier, Andrew McKinstry-Wu, Maxwell Muench

Abstract

Recent modeling and empirical studies support the hypothesis that large-scale brain networks function near a critical state. Similar functional connectivity patterns derived from resting state empirical data and brain network models at criticality provide further support. However, despite the strong implication of a relationship, there has been no principled explanation of how criticality shapes the characteristic functional connectivity in large-scale brain networks. Here, we hypothesized that the network science concept of partial phase locking is the underlying mechanism of optimal functional connectivity in the resting state. We further hypothesized that the characteristic connectivity of the critical state provides a theoretical boundary to quantify how far pharmacologically or pathologically perturbed brain connectivity deviates from its critical state, which could enable the differentiation of various states of consciousness with a theory-based metric.

To test the hypothesis, we used a neuroanatomically informed brain network model with the resulting source signals projected to electroencephalogram (EEG)-like sensor signals with a forward model. Phase lag entropy (PLE), a measure of phase relation diversity, was estimated and the topography of PLE was analyzed. To measure the distance from criticality, the PLE topography at a critical state was compared with those of the EEG data from baseline consciousness, isoflurane anesthesia, ketamine anesthesia, vegetative state/unresponsive wakefulness syndrome, and minimally conscious state.

We demonstrate that the partial phase locking at criticality shapes the functional connectivity and asymmetric anterior-posterior PLE topography, with low (high) PLE for high (low) degree nodes. The topographical similarity and the strength of PLE differentiates various pharmacologic and pathologic states of consciousness. Moreover, this model-based EEG network analysis provides a novel metric to quantify how far a pharmacologically or pathologically perturbed brain network is away from critical state, rather than merely determining whether it is in a critical or non-critical state.

from Imaging via a.sfakia on Inoreader https://ift.tt/2QEcmQN

Passive exposure to speech sounds modifies change detection brain responses in adults

Publication date: Available online 6 December 2018

Source: NeuroImage

Author(s): L.O. Kurkela Jari, A. Hämäläinen Jarmo, H.T. Leppänen Paavo, Shu Hua, Astikainen Piia

Abstract

In early life auditory discrimination ability can be enhanced by passive sound exposure. In contrast, in adulthood passive exposure seems to be insufficient to promote discrimination ability, but this has been tested only with a single short exposure session in humans. We tested whether passive exposure to unfamiliar auditory stimuli can result in enhanced cortical discrimination ability and change detection in adult humans, and whether the possible learning effect generalizes to different stimuli. To address these issues, we exposed adult Finnish participants to Chinese lexical tones passively for 2 h per day on 4 consecutive days. Behavioral responses and the brain's event-related potentials (ERPs) were measured before and after the exposure for the same stimuli applied in the exposure phase and to sinusoidal sounds roughly mimicking the frequency contour in speech sounds. Passive exposure modulated the ERPs to speech sound changes in both ignore (mismatch negativity latency, P3a amplitude and P3a latency) and attend (P3b amplitude) test conditions, but not the behavioral responses. Furthermore, effect of passive exposure transferred to the processing of the sinusoidal sounds as indexed by the latency of the mismatch negativity. No corresponding effects in the ERPs were found in a control group that participated to the test measurements, but received no exposure to the sounds. The results show that passive exposure to foreign speech sounds in adulthood can enhance cortical discrimination ability and attention orientation toward changes in speech sounds and that the learning effect can transfer to non-speech sounds.

from Imaging via a.sfakia on Inoreader https://ift.tt/2QEOqwM

Spatiotemporal analysis for detection of pre-symptomatic shape changes in neurodegenerative diseases: Initial application to the GENFI cohort

Publication date: Available online 6 December 2018

Source: NeuroImage

Author(s): Claire Cury, Stanley Durrleman, David M. Cash, Marco Lorenzi, Jennifer M. Nicholas, Martina Bocchetta, John C. van Swieten, Barbara Borroni, Daniela Galimberti, Mario Masellis, Maria Carmela Tartaglia, James B. Rowe, Caroline Graff, Fabrizio Tagliavini, Giovanni B. Frisoni, Robert Laforce, Elizabeth Finger, Alexandre de Mendonça, Sandro Sorbi, Sebastien Ourselin

Abstract

Brain atrophy as measured from structural MR images, is one of the primary imaging biomarkers used to track neurodegenerative disease progression. In diseases such as frontotemporal dementia or Alzheimer's disease, atrophy can be observed in key brain structures years before any clinical symptoms are present. Atrophy is most commonly captured as volume change of key structures and the shape changes of these structures are typically not analysed despite being potentially more sensitive than summary volume statistics over the entire structure.

In this paper we propose a spatiotemporal analysis pipeline based on Large Diffeomorphic Deformation Metric Mapping (LDDMM) to detect shape changes from volumetric MRI scans. We applied our framework to a cohort of individuals with genetic variants of frontotemporal dementia and healthy controls from the Genetic FTD Initiative (GENFI) study. Our method, take full advantage of the LDDMM framework, and relies on the creation of a population specific average spatiotemporal trajectory of a relevant brain structure of interest, the thalamus in our case. The residuals from each patient data to the average spatiotemporal trajectory are then clustered and studied to assess when presymptomatic mutation carriers differ from healthy control subjects.

We found statistical differences in shape in the anterior region of the thalamus at least five years before the mutation carrier subjects develop any clinical symptoms. This region of the thalamus has been shown to be predominantly connected to the frontal lobe, consistent with the pattern of cortical atrophy seen in the disease.

Graphical abstract

from Imaging via a.sfakia on Inoreader https://ift.tt/2E8Aq7I

A longitudinal study of infant view-invariant face processing during the first 3–8 months of life

Publication date: Available online 5 December 2018

Source: NeuroImage

Author(s): Hiroko Ichikawa, Emi Nakato, Yasuhiko Igarashi, Masato Okada, So Kanazawa, Masami K. Yamaguchi, Ryusuke Kakigi

Abstract

View-invariant face processing emerges early in life. A previous study (Nakato et al., 2009) measured infant hemodynamic responses to faces from the frontal and profile views in the bilateral temporal areas, which have been reported to be involved in face processing using near-infrared spectroscopy. It was reported that 5-month-old infants showed increased oxyhemoglobin (oxy-Hb) responses to frontal faces, but not to profile faces. In contrast, 8-month-old infants displayed increased oxy-Hb responses to profile faces as well as to frontal faces. In this study, we used the experimental method developed in the previous study to investigate the development of view-invariant face processing, every month for 5 months (from the first 3–8 months of life). We longitudinally measured hemodynamic responses to faces from the frontal and profile views in 14 infants. The longitudinal measurements allowed us to investigate individual differences in each participant. We modeled each infant's hemodynamic oxy-Hb responses to frontal and profile faces using linear regression analysis. Processing of profile faces emerged later and underwent larger improvements than that of frontal faces. We also found an anticorrelation between the speed of improvement in face processing and the hemodynamic response to faces at the age of 3- months. Group analysis of the averaged hemodynamic data from the 14 infants using linear regression revealed that the processing of profile faces emerged between 5 and 6 months of age. Infant view-invariant face processing developed first for frontal faces. This was followed by the emergence of processing of profile faces.

from Imaging via a.sfakia on Inoreader https://ift.tt/2E7HPEd

Memory entrainment by visually evoked theta-gamma coupling

Publication date: Available online 5 December 2018

Source: NeuroImage

Author(s): Moritz Köster, Ulla Martens, Thomas Gruber

Abstract

The wake human brain constantly encodes novel information and integrates them into existing neuronal representations. It is posited that the formation of new memory traces is orchestrated by the synchronization of neuronal activity in the theta rhythm (3–8 Hz), theta coupled gamma activity (40–120 Hz), and decreases in the alpha rhythm (8–12 Hz). Critically, given the correlative nature of neurophysiological recordings, the functional relevance of oscillatory processes is not well understood. Here, we experimentally enhanced memory formation processes by a visual stimulation at an individual theta frequency, in contrast to the stimulation at an individual alpha frequency. This memory entrainment effect was not explained by theta power per se, but was driven by visually evoked theta-gamma coupling pattern. This underlines the functional role of the theta rhythm and the theta-gamma neuronal code in human episodic memory. The entrainment of mnemonic network mechanisms by a visual stimulation technique provides a proof of concept that visual pacemakers can entrain complex cognitive processes in the wake human brain.

from Imaging via a.sfakia on Inoreader https://ift.tt/2E5xVTL

Visual stimulus-driven functional organization of macaque prefrontal cortex

Publication date: Available online 3 December 2018

Source: NeuroImage

Author(s): Theodros Haile, Kaitlin S. Bohon, Maria Romero, Bevil R. Conway

Abstract

The extent to which the major subdivisions of prefrontal cortex (PFC) can be functionally partitioned is unclear. In approaching the question, it is often assumed that the organization is task dependent. Here we use fMRI to show that PFC can respond in a task-independent way, and we leverage these responses to uncover a stimulus-driven functional organization. The results were generated by mapping the relative location of responses to faces, bodies, scenes, disparity, color, and eccentricity in passively fixating macaques. The results control for individual differences in functional architecture and provide the first account of a systematic visual stimulus-driven functional organization across PFC. Responses were focused in dorsolateral PFC (DLPFC), in the ventral prearcuate region; and in ventrolateral PFC (VLPFC), extending into orbital PFC. Face patches were in the VLPFC focus and were characterized by a striking lack of response to non-face stimuli rather than an especially strong response to faces. Color-biased regions were near but distinct from face patches. One scene-biased region was consistently localized with different contrasts and overlapped the disparity-biased region to define the DLPFC focus. All visually responsive regions showed a peripheral visual-field bias. These results uncover an organizational scheme that presumably constrains the flow of information about different visual modalities into PFC.

Graphical abstract

from Imaging via a.sfakia on Inoreader https://ift.tt/2B12IOj

Adaptive task difficulty influences neural plasticity and transfer of training

Publication date: Available online 3 December 2018

Source: NeuroImage

Author(s): Kristin E. Flegal, J. Daniel Ragland, Charan Ranganath

Abstract

The efficacy of cognitive training is controversial, and research progress in the field requires an understanding of factors that promote transfer of training gains and their relationship to changes in brain activity. One such factor may be adaptive task difficulty, as adaptivity is predicted to facilitate more efficient processing by creating a prolonged mismatch between the supply of, and the demand upon, neural resources. To test this hypothesis, we measured behavioral and neural plasticity in fMRI sessions before and after 10 sessions of working memory updating (WMU) training, in which the difficulty of practiced tasks either adaptively increased in response to performance or was fixed. Adaptive training resulted in transfer to an untrained episodic memory task and activation decreases in striatum and hippocampus on a trained WMU task, and the amount of training task improvement was associated with near transfer to other WMU tasks and with hippocampal activation changes on both near and far transfer tasks. These findings suggest that cognitive training programs should incorporate adaptive task difficulty to broaden transfer of training gains and maximize efficiency of task-related brain activity.

from Imaging via a.sfakia on Inoreader https://ift.tt/2G6pav4