Characterization of cochlear implant artifacts in electrically evoked auditory steady-state responses

AbstractObjectiveElectrically evoked auditory steady-state responses (EASSRs) are neural potentials measured in the electroencephalogram (EEG) in response to periodic pulse trains presented, for example, through a cochlear implant (CI). EASSRs could potentially be used for objective CI fitting. However, EEG signals are contaminated with electrical CI artifacts. In this paper, we characterized the CI artifacts for monopolar mode stimulation and evaluated at which pulse rate, linear interpolation over the signal part contaminated with CI artifact is successful.MethodsCI artifacts were characterized by means of their amplitude growth functions and duration.ResultsCI artifact durations were between 0.7 and 1.7ms, at contralateral recording electrodes. At ipsilateral recording electrodes, CI artifact durations are range from 0.7 to larger than 2ms.ConclusionAt contralateral recording electrodes, the artifact was shorter than the interpulse interval across subjects for 500pps, which was not always the case for 900pps.SignificanceCI artifact-free EASSRs are crucial for reliable CI fitting and neuroscience research. The CI artifact has been characterized and linear interpolation allows to remove it at contralateral recording electrodes for stimulation at 500pps

A Systematic Literature Review of Integrated STEM Education: Uncovering Consensus and Diversity in Principles and Characteristics

Integrated STEM education is increasingly present in classrooms and in educational research, as it is proposed as a possible strategy to improve the problems of students’ lack of interest in scientific–technological disciplines. However, this increased interest in STEM education has been paralleled by a loss of cohesion in the interpretations of its theoretical basis and by an ongoing discussion on integrated STEM education’s foundations, making its understanding, translation into real projects, and evaluation difficult to undertake. Published articles defining a STEM theoretical framework have different descriptions, so the aim of this systematic literature review is to analyse these explanations and compare them with each other. Following the PRISMA 2020 guidelines, 27 articles of interest about STEM and STEAM education were obtained and analysed with a focus on the principles and characteristics described in the texts. After organising the information and analysing the similarities and differences in the principles and characteristics, we concluded that there is great consensus on the principles of “integration”, “real-world problems”, “inquiry”, “design”, and “teamwork”. Nonetheless, this review identifies areas of discussion regarding both the principles and their characteristics that invite further analysis to refine our understanding of what integrated STEM education should entail.This research was funded by the Spanish government MINECO\FEDER grant number. PID2019-105172RB-I00) and the APC was founded by the Basque Country Government (Ikasgaraia Research Group IT1637/22)

A mutation update for the FLNC gene in myopathies and cardiomyopathies

Filamin C (FLNC) variants are associated with cardiac and muscular phenotypes. Originally, FLNC variants were described in myofibrillar myopathy (MFM) patients. Later, high-throughput screening in cardiomyopathy cohorts determined a prominent role for FLNC in isolated hypertrophic and dilated cardiomyopathies (HCM and DCM). FLNC variants are now among the more prevalent causes of genetic DCM. FLNC-associated DCM is associated with a malignant clinical course and a high risk of sudden cardiac death. The clinical spectrum of FLNC suggests different pathomechanisms related to variant types and their location in the gene. The appropriate functioning of FLNC is crucial for structural integrity and cell signaling of the sarcomere. The secondary protein structure of FLNC is critical to ensure this function. Truncating variants with subsequent haploinsufficiency are associated with DCM and cardiac arrhythmias. Interference with the dimerization and folding of the protein leads to aggregate formation detrimental for muscle function, as found in HCM and MFM. Variants associated with HCM are predominantly missense variants, which cluster in the ROD2 domain. This domain is important for binding to the sarcomere and to ensure appropriate cell signaling. We here review FLNC genotype–phenotype correlations based on available evidence.</p

A mutation update for the FLNC gene in myopathies and cardiomyopathies

Filamin C (FLNC) variants are associated with cardiac and muscular phenotypes. Originally, FLNC variants were described in myofibrillar myopathy (MFM) patients. Later, high-throughput screening in cardiomyopathy cohorts determined a prominent role for FLNC in isolated hypertrophic and dilated cardiomyopathies (HCM and DCM). FLNC variants are now among the more prevalent causes of genetic DCM. FLNC-associated DCM is associated with a malignant clinical course and a high risk of sudden cardiac death. The clinical spectrum of FLNC suggests different pathomechanisms related to variant types and their location in the gene. The appropriate functioning of FLNC is crucial for structural integrity and cell signaling of the sarcomere. The secondary protein structure of FLNC is critical to ensure this function. Truncating variants with subsequent haploinsufficiency are associated with DCM and cardiac arrhythmias. Interference with the dimerization and folding of the protein leads to aggregate formation detrimental for muscle function, as found in HCM and MFM. Variants associated with HCM are predominantly missense variants, which cluster in the ROD2 domain. This domain is important for binding to the sarcomere and to ensure appropriate cell signaling. We here review FLNC genotype–phenotype correlations based on available evidence.</p

A mutation update for the FLNC gene in myopathies and cardiomyopathies

Filamin C (FLNC) variants are associated with cardiac and muscular phenotypes. Originally, FLNC variants were described in myofibrillar myopathy (MFM) patients. Later, high-throughput screening in cardiomyopathy cohorts determined a prominent role for FLNC in isolated hypertrophic and dilated cardiomyopathies (HCM and DCM). FLNC variants are now among the more prevalent causes of genetic DCM. FLNC-associated DCM is associated with a malignant clinical course and a high risk of sudden cardiac death. The clinical spectrum of FLNC suggests different pathomechanisms related to variant types and their location in the gene. The appropriate functioning of FLNC is crucial for structural integrity and cell signaling of the sarcomere. The secondary protein structure of FLNC is critical to ensure this function. Truncating variants with subsequent haploinsufficiency are associated with DCM and cardiac arrhythmias. Interference with the dimerization and folding of the protein leads to aggregate formation detrim

A mutation update for the FLNC gene in myopathies and cardiomyopathies

Filamin C (FLNC) variants are associated with cardiac and muscular phenotypes. Originally, FLNC variants were described in myofibrillar myopathy (MFM) patients. Later, high-throughput screening in cardiomyopathy cohorts determined a prominent role for FLNC in isolated hypertrophic and dilated cardiomyopathies (HCM and DCM). FLNC variants are now among the more prevalent causes of genetic DCM. FLNC-associated DCM is associated with a malignant clinical course and a high risk of sudden cardiac death. The clinical spectrum of FLNC suggests different pathomechanisms related to variant types and their location in the gene. The appropriate functioning of FLNC is crucial for structural integrity and cell signaling of the sarcomere. The secondary protein structure of FLNC is critical to ensure this function. Truncating variants with subsequent haploinsufficiency are associated with DCM and cardiac arrhythmias. Interference with the dimerization and folding of the protein leads to aggregate formation detrimental for muscle function, as found in HCM and MFM. Variants associated with HCM are predominantly missense variants, which cluster in the ROD2 domain. This domain is important for binding to the sarcomere and to ensure appropriate cell signaling. We here review FLNC genotype–phenotype correlations based on available evidence

Cochlear Implant Artifact Suppression in EEG Measurements

Cochlear implants (CIs) aim to restore hearing in severely to profoundly deaf adults, children and infants. Electrically evoked auditory steady-state responses (EASSRs) are neural responses to continuous modulated pulse trains, and can be objectively detected at the modulation frequency in the electro-encephalogram (EEG). EASSRs provide a number of advantages over other objective measures, because frequency-specific stimuli are used, because targeted brain areas can be studied, depending on the chosen stimulation parameters, and because they can objectively be detected using statistical methods. EASSRs can potentially be used to determine appropriate stimulation levels during CI fitting, without behavioral input from the subjects. Furthermore, speech understanding in noise varies greatly between CI subjects. EASSRs lend themselves well to study the underlying causes of this variability, such as the integrity of the electrode-neuron interface or changes in the auditory cortex following deafness and following cochlear implantation. EASSRs are distorted by electrical artifacts, caused by the CI's radiofrequency link and by the electrical pulses used to stimulate the auditory nerve. CI artifacts may also be present at the modulation frequency, leading to inaccurate EASSR detection and unreliable EASSR amplitude and phase estimations. CI artifacts that are shorter than the interpulse interval (IPI), i.e., the inverse of the pulse rate (in pulses per second (pps)), can be removed with a linear interpolation (LI) over the EEG samples affected by CI artifacts. For clinically used monopolar (MP) mode stimulation, i.e., between an intracochlear and an extracochlear electrode, CI artifacts are longer than for bipolar (BP) mode stimulation, i.e., between two intracochlear electrodes. In this thesis, CI artifacts are characterized based on the CI artifact duration and based on the CI artifact amplitude growth function (AGF). Furthermore, three methods for CI artifact suppression to enable reliable estimation of EASSR parameters are developed and evaluated. The CI artifacts are larger and longer in recording channels closer to the implant. Appropriate reference electrode selection may lead to smaller and shorter CI artifacts, that are more easily suppressed. Using LI, CI artifacts may be suppressed in contralateral recording channels for 500 pps stimulation for our recording set-up. More advanced CI artifact suppression methods are needed to measure EASSRs in ipsilateral channels (for source localization or lateralization studies) and in infants and children. First, a CI artifact suppression method based on independent component analysis (ICA) is developed. Independent components (ICs) associated with CI artifact are automatically identified and rejected based on the component at the pulse rate. In some cases, CI artifacts are successfully removed, although mixed results are obtained in other cases. Because the ICA method is not fully robust, and since multichannel recordings are needed, a second method, based on template subtraction (TS), is developed. With TS, for each stimulation pulse amplitude, the CI artifact pulse templates are constructed based on a recording containing no significant EASSR. The templates are then put in the correct order and subtracted from the recording of interest. With TS, reliable EASSR amplitudes, phases and latencies are obtained for a high signal-to-noise ratio (SNR) dataset. The template construction recording duration can be reduced to 60 s, while reliable EASSR parameter estimations are still obtained. Because the previous method requires additional data collection, a third method for EASSR parameter estimation in the presence of CI artifacts is developed. The method is based on a Kalman filter (KF), as proposed in (Luke, 2016). The CI artifact model presented in (Luke, 2016) consists of constant triangular pulses presented at the stimulation pulse rate, and proved to work well for CI artifacts in contralateral recording channels for BP mode stimulation. In more general cases, i.e., with MP mode stimulation and in ipsilateral channels, CI artifacts are modulated and have an exponentially decaying tail. An extended state-space model is developed that contains additional components modeling these CI artifact features. With the new KF method, reliable EASSR amplitudes, phases and latencies are again obtained for a high signal-to-noise ratio (SNR) dataset, without the need for additional data collection. The insights provided in this thesis and the developed CI artifact suppression methods may assist researchers and clinicians to record EASSRs in the presence of CI artifacts for clinical stimulation parameters. These responses may then be used to improve CI rehabilitation or CI stimulation strategies, leading to a better quality-of-life for all patients with a CI.nrpages: 173status: publishe

Het readySTEMgo project draagt zijn steentje bij aan een onderbouwde studiekeuzebegeleiding

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