Κυριακή 31 Δεκεμβρίου 2017

Incorporating behavioral and sensory context into spectro-temporal models of auditory encoding

Publication date: Available online 31 December 2017
Source:Hearing Research
Author(s): Stephen V. David
For several decades, auditory neuroscientists have used spectro-temporal encoding models to understand how neurons in the auditory system represent sound. Derived from early applications of systems identification tools to the auditory periphery, the spectro-temporal receptive field (STRF) and more sophisticated variants have emerged as an efficient means of characterizing representation throughout the auditory system. Most of these encoding models describe neurons as static sensory filters. However, auditory neural coding is not static. Sensory context, reflecting the acoustic environment, and behavioral context, reflecting the internal state of the listener, can both influence sound-evoked activity, particularly in central auditory areas. This review explores recent efforts to integrate context into spectro-temporal encoding models. It begins with a brief tutorial on the basics of estimating and interpreting STRFs. Then it describes three recent studies that have characterized contextual effects on STRFs, emerging over a range of timescales, from many minutes to tens of milliseconds. An important theme of this work is not simply that context influences auditory coding, but also that contextual effects span a large continuum of internal states. The added complexity of these context-dependent models introduces new experimental and theoretical challenges that must be addressed in order to be used effectively. Several new methodological advances promise to address these limitations and allow the development of more comprehensive context-dependent models in the future.



from #Audiology via ola Kala on Inoreader http://ift.tt/2lviv0R
via IFTTT

Incorporating behavioral and sensory context into spectro-temporal models of auditory encoding

Publication date: Available online 31 December 2017
Source:Hearing Research
Author(s): Stephen V. David
For several decades, auditory neuroscientists have used spectro-temporal encoding models to understand how neurons in the auditory system represent sound. Derived from early applications of systems identification tools to the auditory periphery, the spectro-temporal receptive field (STRF) and more sophisticated variants have emerged as an efficient means of characterizing representation throughout the auditory system. Most of these encoding models describe neurons as static sensory filters. However, auditory neural coding is not static. Sensory context, reflecting the acoustic environment, and behavioral context, reflecting the internal state of the listener, can both influence sound-evoked activity, particularly in central auditory areas. This review explores recent efforts to integrate context into spectro-temporal encoding models. It begins with a brief tutorial on the basics of estimating and interpreting STRFs. Then it describes three recent studies that have characterized contextual effects on STRFs, emerging over a range of timescales, from many minutes to tens of milliseconds. An important theme of this work is not simply that context influences auditory coding, but also that contextual effects span a large continuum of internal states. The added complexity of these context-dependent models introduces new experimental and theoretical challenges that must be addressed in order to be used effectively. Several new methodological advances promise to address these limitations and allow the development of more comprehensive context-dependent models in the future.



from #Audiology via ola Kala on Inoreader http://ift.tt/2lviv0R
via IFTTT

Surface EMG patterns for quantification of thigh muscle co-contraction in school-age children: Normative data during walking

Publication date: March 2018
Source:Gait & Posture, Volume 61
Author(s): Francesco Di Nardo, Annachiara Strazza, Alessandro Mengarelli, Serena Ercolani, Nicole Morgoni, Laura Burattini, Valentina Agostini, Marco Knaflitz, Sandro Fioretti
Muscle co-contractions are particularly relevant in analyzing children pathologies. To interpret surface electromyography (sEMG) in pathological conditions, reliable normative data in non-pathological children are required for direct comparison. Aim of the study was the quantification of co-contraction activity between quadriceps femoris (QF) and hamstring muscles during walking in healthy children. To this aim, Statistical gait analysis was performed on sEMG signals from rectus femoris (RF), vastus medialis (VM), and lateral hamstrings (LH), in 16401 strides walked by 100 healthy school-age children. Co-contractions were assessed as overlapping period between activation intervals of considered muscles. Results showed full superimpositions of LH with both RF and VL activity from terminal swing, 80–100% of gait cycle, to successive loading response (0–15% of gait cycle), in around 90% of strides, as reported in adults. This indicates that children regularly use a cocontraction activity between QF and hamstring muscles in weight acceptance during walking, supporting the hypothesis of a regulatory role of co-contraction in providing knee joint stability. Concomitant activity of QF and hamstring muscles was detected also during push-off phase (30–50% of gait cycle), showing a large variability intra and inter subjects and a lower occurrence frequency (around 25% of strides). This could be intended for controlling rapid knee flexion and/or stabilizing pelvis during body progression. Present findings represent the first attempt to provide normative sEMG dataset on variability of QF and hamstring muscles co-contractions during child walking, useful for discriminating physiological and pathological behavior and for designing future studies on maturation of gait.



from #Audiology via xlomafota13 on Inoreader http://ift.tt/2lz3yKt
via IFTTT

Surface EMG patterns for quantification of thigh muscle co-contraction in school-age children: Normative data during walking

Publication date: March 2018
Source:Gait & Posture, Volume 61
Author(s): Francesco Di Nardo, Annachiara Strazza, Alessandro Mengarelli, Serena Ercolani, Nicole Morgoni, Laura Burattini, Valentina Agostini, Marco Knaflitz, Sandro Fioretti
Muscle co-contractions are particularly relevant in analyzing children pathologies. To interpret surface electromyography (sEMG) in pathological conditions, reliable normative data in non-pathological children are required for direct comparison. Aim of the study was the quantification of co-contraction activity between quadriceps femoris (QF) and hamstring muscles during walking in healthy children. To this aim, Statistical gait analysis was performed on sEMG signals from rectus femoris (RF), vastus medialis (VM), and lateral hamstrings (LH), in 16401 strides walked by 100 healthy school-age children. Co-contractions were assessed as overlapping period between activation intervals of considered muscles. Results showed full superimpositions of LH with both RF and VL activity from terminal swing, 80–100% of gait cycle, to successive loading response (0–15% of gait cycle), in around 90% of strides, as reported in adults. This indicates that children regularly use a cocontraction activity between QF and hamstring muscles in weight acceptance during walking, supporting the hypothesis of a regulatory role of co-contraction in providing knee joint stability. Concomitant activity of QF and hamstring muscles was detected also during push-off phase (30–50% of gait cycle), showing a large variability intra and inter subjects and a lower occurrence frequency (around 25% of strides). This could be intended for controlling rapid knee flexion and/or stabilizing pelvis during body progression. Present findings represent the first attempt to provide normative sEMG dataset on variability of QF and hamstring muscles co-contractions during child walking, useful for discriminating physiological and pathological behavior and for designing future studies on maturation of gait.



from #Audiology via ola Kala on Inoreader http://ift.tt/2lz3yKt
via IFTTT

Surface EMG patterns for quantification of thigh muscle co-contraction in school-age children: Normative data during walking

Publication date: March 2018
Source:Gait & Posture, Volume 61
Author(s): Francesco Di Nardo, Annachiara Strazza, Alessandro Mengarelli, Serena Ercolani, Nicole Morgoni, Laura Burattini, Valentina Agostini, Marco Knaflitz, Sandro Fioretti
Muscle co-contractions are particularly relevant in analyzing children pathologies. To interpret surface electromyography (sEMG) in pathological conditions, reliable normative data in non-pathological children are required for direct comparison. Aim of the study was the quantification of co-contraction activity between quadriceps femoris (QF) and hamstring muscles during walking in healthy children. To this aim, Statistical gait analysis was performed on sEMG signals from rectus femoris (RF), vastus medialis (VM), and lateral hamstrings (LH), in 16401 strides walked by 100 healthy school-age children. Co-contractions were assessed as overlapping period between activation intervals of considered muscles. Results showed full superimpositions of LH with both RF and VL activity from terminal swing, 80–100% of gait cycle, to successive loading response (0–15% of gait cycle), in around 90% of strides, as reported in adults. This indicates that children regularly use a cocontraction activity between QF and hamstring muscles in weight acceptance during walking, supporting the hypothesis of a regulatory role of co-contraction in providing knee joint stability. Concomitant activity of QF and hamstring muscles was detected also during push-off phase (30–50% of gait cycle), showing a large variability intra and inter subjects and a lower occurrence frequency (around 25% of strides). This could be intended for controlling rapid knee flexion and/or stabilizing pelvis during body progression. Present findings represent the first attempt to provide normative sEMG dataset on variability of QF and hamstring muscles co-contractions during child walking, useful for discriminating physiological and pathological behavior and for designing future studies on maturation of gait.



from #Audiology via ola Kala on Inoreader http://ift.tt/2lz3yKt
via IFTTT

A novel pathogenic variant c.975G>A (p.Trp325*) in the POU3F4 gene in Yakut family (Eastern Siberia, Russia) with the X-linked deafness-2 (DFNX2).

Related Articles

A novel pathogenic variant c.975G>A (p.Trp325*) in the POU3F4 gene in Yakut family (Eastern Siberia, Russia) with the X-linked deafness-2 (DFNX2).

Int J Pediatr Otorhinolaryngol. 2018 Jan;104:94-97

Authors: Barashkov NA, Klarov LA, Teryutin FM, Solovyev AV, Pshennikova VG, Konnikova EE, Romanov GP, Tobokhov AV, Morozov IV, Bondar AA, Posukh OL, Dzhemileva LU, Tomsky MI, Khusnutdinova EK, Fedorova SA

Abstract
Here, we report a novel hemizygous transition c.975G>A (p.Trp325*) in POU3F4 gene (Xq21) found in two deaf half-brothers from one Yakut family (Eastern Siberia, Russia) with identical inner ear abnormalities ("corkscrew" cochlea with an absence of modiolus) specific to X-linked deafness-2 (DFNX2). Comprehensive clinical evaluation (CT and MR-imaging, audiological and stabilometric examinations) of available members of this family revealed both already known (mixed progressive hearing loss) and additional (enlargement of semicircular canals and postural disorders) clinical DFNX2 features in affected males with c.975G>A (p.Trp325*). Moreover, mild enlargement of semicircular canals, postural abnormalities and different types of hearing thresholds were found in female carrier of this POU3F4-variant.

PMID: 29287890 [PubMed - in process]



from #Audiology via xlomafota13 on Inoreader http://ift.tt/2CkHdeb
via IFTTT

A novel mutation of the EYA4 gene associated with post-lingual hearing loss in a proband is co-segregating with a novel PAX3 mutation in two congenitally deaf family members.

Related Articles

A novel mutation of the EYA4 gene associated with post-lingual hearing loss in a proband is co-segregating with a novel PAX3 mutation in two congenitally deaf family members.

Int J Pediatr Otorhinolaryngol. 2018 Jan;104:88-93

Authors: Cesca F, Bettella E, Polli R, Cama E, Scimemi P, Santarelli R, Murgia A

Abstract
OBJECTIVES: This work was aimed at establishing the molecular etiology of hearing loss in a 9-year old girl with post-lingual non-syndromic mild sensorineural hearing loss with a complex family history of clinically heterogeneous deafness.
METHODS: The proband's DNA was subjected to NGS analysis of a 59-targeted gene panel, with the use of the Ion Torrent PGM platform. Conventional Sanger sequencing was used for segregation analysis in all the affected relatives. The proband and all the other hearing impaired members of the family underwent a thorough clinical and audiological evaluation.
RESULTS: A new likely pathogenic mutation in the EYA4 gene (c.1154C > T; p.Ser385Leu) was identified in the proband and in her 42-year-old father with post-lingual non-syndromic profound sensorineural hearing loss. The EYA4 mutation was also found in the proband's grandfather and uncle, both showing clinical features of Waardenburg syndrome type 1. A novel pathogenic splice-site mutation (c.321+1G > A) of the PAX3 gene was found to co-segregate with the EYA4 mutation in these two subjects.
CONCLUSION: The identified novel EYA4 mutation can be considered responsible of the hearing loss observed in the proband and her father, while a dual molecular diagnosis was reached in the relatives co-segregating the EYA4 and the PAX3 mutations. In these two subjects the DFNA10 phenotype was masked by Waardenburg syndrome. The use of NGS targeted gene-panel, in combination with an extensive clinical and audiological examination led us to identify the genetic cause of the hearing loss in members of a family in which different forms of autosomal dominant deafness segregate. These results provide precise and especially important prognostic and follow-up information for the future audiologic management in the youngest affected member.

PMID: 29287889 [PubMed - in process]



from #Audiology via xlomafota13 on Inoreader http://ift.tt/2Cr3kQd
via IFTTT

A novel splicing mutation in SMPX is linked to nonsyndromic progressive hearing loss.

Related Articles

A novel splicing mutation in SMPX is linked to nonsyndromic progressive hearing loss.

Int J Pediatr Otorhinolaryngol. 2018 Jan;104:47-50

Authors: Niu Z, Yan D, Bressler S, Mei L, Feng Y, Liu X

Abstract
OBJECTIVE: X-linked nonsyndromic hearing impairment is the rarest form of genetic hearing loss and represents only a minor fraction of all cases. The aim of this study was to investigate the cause of X-linked nonsyndromic sensorineural hearing loss in a three-generation American family.
METHODS: Whole-exome sequencing and co-segregation analysis were used to identify disease-causing genes.
RESULTS: In this study, we described in detail the clinical characteristics of the family and identified a novel frameshift mutation creating a premature stop codon (c.133-1 G > A, p.(Gly45fs*36)) of SMPX. The loss-of-function mutation was co-segregated with the progressive hearing loss phenotype and was absent in 200 normal controls.
CONCLUSIONS: We report the first SMPX (DFNX4) mutation in a North American family. Our findings contribute to the existing genotypic and phenotypic spectrum of SMPX associated hearing loss. Furthermore, our data suggest that exome sequencing is promising in the genetic diagnosis of hearing loss.

PMID: 29287879 [PubMed - in process]



from #Audiology via xlomafota13 on Inoreader http://ift.tt/2CrDbAs
via IFTTT

Germinal mosaicism of PAX3 mutation caused Waardenburg syndrome type I.

Related Articles

Germinal mosaicism of PAX3 mutation caused Waardenburg syndrome type I.

Int J Pediatr Otorhinolaryngol. 2018 Jan;104:200-204

Authors: Chen K, Zhan Y, Wu X, Zong L, Jiang H

Abstract
OBJECTIVES: Waardenburg syndrome mutations are most often recurrent or de novo. The rate of familial recurrence is low and families with several affected children are extremely rare. In this study, we aimed to clarify the underlying hereditary cause of Waardenburg syndrome type I in two siblings in a Chinese family, with a mother affected by prelingual mild hearing loss and a father who was negative for clinical symptoms of Waardenburg syndrome and had a normal hearing threshold.
METHODS: Complete characteristic features of the family members were recorded and genetic sequencing and parent-child relationship analyses were performed.
RESULTS: The two probands were found to share double mutations in the PAX3/GJB2 genes that caused concurrent hearing loss in Waardenburg syndrome type I. Their mother carried the GJB2 c.109G > A homozygous mutation; however, neither the novel PAX3 c.592delG mutation, nor the Waardenburg syndrome phenotype, was observed in either parent.
CONCLUSION: These previously unreported digenic mutations in PAX3/GJB2 resulted in deafness associated with Waardenburg syndrome type I in this family. To our knowledge, this is the first report describing germinal mosaicism in Waardenburg syndrome. This concept is important because it complicates genetic counseling of this family regarding the risk of recurrence of the mutations in subsequent pregnancies.

PMID: 29287868 [PubMed - in process]



from #Audiology via xlomafota13 on Inoreader http://ift.tt/2CpPHkc
via IFTTT

SLC52A2 mutations cause SCABD2 phenotype: A second report.

Related Articles

SLC52A2 mutations cause SCABD2 phenotype: A second report.

Int J Pediatr Otorhinolaryngol. 2018 Jan;104:195-199

Authors: Babanejad M, Adeli OA, Nikzat N, Beheshtian M, Azarafra H, Sadeghnia F, Mohseni M, Najmabadi H, Kahrizi K

Abstract
INTRODUCTION: Autosomal recessive cerebellar ataxias (ARCAs) are a large group of neurodegenerative disorders that manifest mainly in children and young adults. Most ARCAs are heterogeneous with respect to age at onset, severity of disease progression, and frequency of extracerebellar and systemic signs.
METHODS: The phenotype of a consanguineous Iranian family was characterized using clinical testing and pedigree analysis. Whole-exome sequencing was used to identify the disease-causing gene in this family.
RESULTS AND CONCLUSION: Using whole exome sequencing (WES), a novel missense mutation in SLC52A2 gene is reported in a consanguineous Iranian family with progressive severe hearing loss, optic atrophy and ataxia. This is the second report of the genotype-phenotype correlation between this syndrome named spinocerebellar ataxia with blindness and deafness type 2 (SCABD2) and SLC52A2 gene.

PMID: 29287867 [PubMed - in process]



from #Audiology via xlomafota13 on Inoreader http://ift.tt/2Cqj8SW
via IFTTT

A novel variant in the CDH23 gene is associated with non-syndromic hearing loss in a Chinese family.

Related Articles

A novel variant in the CDH23 gene is associated with non-syndromic hearing loss in a Chinese family.

Int J Pediatr Otorhinolaryngol. 2018 Jan;104:108-112

Authors: Liang Y, Wang K, Peng Q, Zhu P, Wu C, Rao C, Chang J, Li S, Lu X

Abstract
OBJECTIVES: To explore the pathogenic causes of a proband who was diagnosed with non-syndromic hearing loss.
METHODS: We performed targeted capture of 159 known deafness-related genes and next-generation sequencing in the proband who was tested negative for the twenty hotspot variants in four common deafness-related genes(GJB2, GJB3, SLC26A4 and MTRNR1); Clinical reassessments, including detailed audiological and ocular examinations were performed in the proband and his normal parents.
RESULTS: We identified a novel heterozygous variant of CDH23:c.4567A > G (p.Asn1523Asp) in exon 37 (NM_022124), in conjunction with a reported mutation of CDH23:c.5101G > A (p.Glu1701Lys) in exon 40, to be a potentially pathogenic compound heterozygosity in the proband. The unaffected father has a heterozygous variant of CDH23:c.4567A > G, and the normal mother has another heterozygous variant, CDH23:c.5101G > A. The novel variant was absent in the 1000 Genomes Project. The clinical reassessments revealed binaural profound sensorineural hearing loss (DFNB12) without retinitis pigmentosa in the proband.
CONCLUSIONS: This study demonstrates that the novel variant c.4567A > G (p.Asn1523Asp) in compound heterozygosity with c.5101G > A (p. Glu1701Lys) in the CDH23 gene is the main cause of DFNB12 in the proband. Simultaneously, this study provides a foundation to further elucidate the CDH23-related mechanisms of DFNB12.

PMID: 29287849 [PubMed - in process]



from #Audiology via xlomafota13 on Inoreader http://ift.tt/2Co6i7S
via IFTTT