The Experts below are selected from a list of 1215 Experts worldwide ranked by ideXlab platform

Yoshio Okada - One of the best experts on this subject based on the ideXlab platform.

  • influence of unfused cranial bones on magnetoencephalography signals in human infants
    Clinical Neurophysiology, 2021
    Co-Authors: Seok Lew, Matti Hamalainen, Seppo P Ahlfors, Yoshio Okada
    Abstract:

    Abstract Objective To clarify the effects of unfused cranial bones on magnetoencephalography (MEG) signals during early development. Methods In a simulation study, we compared the MEG signals over a spherical head model with a circular hole mimicking the anterior Fontanel to those over the same head model without the Fontanel for different head and Fontanel sizes with varying skull thickness and conductivity. Results The Fontanel had small effects according to three indices. The sum of differences in signal over a sensor array due to a Fontanel, for example, was  Conclusion MEG signal is weakly affected by a Fontanel. However, the effects can be extensive and significant for radial sources, thicker skull and large Fontanels. The Fontanel effects can be intuitively explained by the concept of secondary sources at the Fontanel wall. Significance The minor influence of unfused cranial bones simplifies MEG analysis, but it should be considered for quantitative analysis.

  • effects of sutures and Fontanels on meg and eeg source analysis in a realistic infant head model
    NeuroImage, 2013
    Co-Authors: Seok Lew, Yoshio Okada, Danielle D Sliva, Myongsun Choe, Ellen P Grant, Carsten H Wolters, Matti Hamalainen
    Abstract:

    In infants, the Fontanels and sutures as well as conductivity of the skull influence the volume currents accompanying primary currents generated by active neurons and thus the associated electroencephalography (EEG) and magnetoencephalography (MEG) signals. We used a finite element method (FEM) to construct a realistic model of the head of an infant based on MRI images. Using this model, we investigated the effects of the Fontanels, sutures and skull conductivity on forward and inverse EEG and MEG source analysis. Simulation results show that MEG is better suited than EEG to study early brain development because it is much less sensitive than EEG to distortions of the volume current caused by the Fontanels and sutures and to inaccurate estimates of skull conductivity. Best results will be achieved when MEG and EEG are used in combination.

Seok Lew - One of the best experts on this subject based on the ideXlab platform.

  • influence of unfused cranial bones on magnetoencephalography signals in human infants
    Clinical Neurophysiology, 2021
    Co-Authors: Seok Lew, Matti Hamalainen, Seppo P Ahlfors, Yoshio Okada
    Abstract:

    Abstract Objective To clarify the effects of unfused cranial bones on magnetoencephalography (MEG) signals during early development. Methods In a simulation study, we compared the MEG signals over a spherical head model with a circular hole mimicking the anterior Fontanel to those over the same head model without the Fontanel for different head and Fontanel sizes with varying skull thickness and conductivity. Results The Fontanel had small effects according to three indices. The sum of differences in signal over a sensor array due to a Fontanel, for example, was  Conclusion MEG signal is weakly affected by a Fontanel. However, the effects can be extensive and significant for radial sources, thicker skull and large Fontanels. The Fontanel effects can be intuitively explained by the concept of secondary sources at the Fontanel wall. Significance The minor influence of unfused cranial bones simplifies MEG analysis, but it should be considered for quantitative analysis.

  • effects of sutures and Fontanels on meg and eeg source analysis in a realistic infant head model
    NeuroImage, 2013
    Co-Authors: Seok Lew, Yoshio Okada, Danielle D Sliva, Myongsun Choe, Ellen P Grant, Carsten H Wolters, Matti Hamalainen
    Abstract:

    In infants, the Fontanels and sutures as well as conductivity of the skull influence the volume currents accompanying primary currents generated by active neurons and thus the associated electroencephalography (EEG) and magnetoencephalography (MEG) signals. We used a finite element method (FEM) to construct a realistic model of the head of an infant based on MRI images. Using this model, we investigated the effects of the Fontanels, sutures and skull conductivity on forward and inverse EEG and MEG source analysis. Simulation results show that MEG is better suited than EEG to study early brain development because it is much less sensitive than EEG to distortions of the volume current caused by the Fontanels and sutures and to inaccurate estimates of skull conductivity. Best results will be achieved when MEG and EEG are used in combination.

Matti Hamalainen - One of the best experts on this subject based on the ideXlab platform.

  • influence of unfused cranial bones on magnetoencephalography signals in human infants
    Clinical Neurophysiology, 2021
    Co-Authors: Seok Lew, Matti Hamalainen, Seppo P Ahlfors, Yoshio Okada
    Abstract:

    Abstract Objective To clarify the effects of unfused cranial bones on magnetoencephalography (MEG) signals during early development. Methods In a simulation study, we compared the MEG signals over a spherical head model with a circular hole mimicking the anterior Fontanel to those over the same head model without the Fontanel for different head and Fontanel sizes with varying skull thickness and conductivity. Results The Fontanel had small effects according to three indices. The sum of differences in signal over a sensor array due to a Fontanel, for example, was  Conclusion MEG signal is weakly affected by a Fontanel. However, the effects can be extensive and significant for radial sources, thicker skull and large Fontanels. The Fontanel effects can be intuitively explained by the concept of secondary sources at the Fontanel wall. Significance The minor influence of unfused cranial bones simplifies MEG analysis, but it should be considered for quantitative analysis.

  • effects of sutures and Fontanels on meg and eeg source analysis in a realistic infant head model
    NeuroImage, 2013
    Co-Authors: Seok Lew, Yoshio Okada, Danielle D Sliva, Myongsun Choe, Ellen P Grant, Carsten H Wolters, Matti Hamalainen
    Abstract:

    In infants, the Fontanels and sutures as well as conductivity of the skull influence the volume currents accompanying primary currents generated by active neurons and thus the associated electroencephalography (EEG) and magnetoencephalography (MEG) signals. We used a finite element method (FEM) to construct a realistic model of the head of an infant based on MRI images. Using this model, we investigated the effects of the Fontanels, sutures and skull conductivity on forward and inverse EEG and MEG source analysis. Simulation results show that MEG is better suited than EEG to study early brain development because it is much less sensitive than EEG to distortions of the volume current caused by the Fontanels and sutures and to inaccurate estimates of skull conductivity. Best results will be achieved when MEG and EEG are used in combination.

Siri Ann Nyrnes - One of the best experts on this subject based on the ideXlab platform.

  • neodoppler new ultrasound technology for continous cerebral circulation monitoring in neonates
    Pediatric Research, 2020
    Co-Authors: Hans Torp, Turid Follestad, Ragnhild Stoen, Siri Ann Nyrnes
    Abstract:

    There is a strong need for continuous cerebral circulation monitoring in neonatal care, since suboptimal cerebral blood flow may lead to brain injuries in preterm infants and other critically ill neonates. NeoDoppler is a novel ultrasound system, which can be gently fixed to the anterior Fontanel and measure cerebral blood flow velocity continuously in different depths of the brain simultaneously. We aimed to study the feasibility, accuracy, and potential clinical applications of NeoDoppler in preterm infants and sick neonates. Twenty-five infants born at different gestational ages with a variety of diagnoses on admission were included. The probe was placed over the anterior Fontanel, and blood flow velocity data were continuously recorded. To validate NeoDoppler, we compared the measurements with conventional ultrasound; agreement was assessed using Bland–Altman plots. NeoDoppler can provide accurate and continuous data on cerebral blood flow velocity in several depths simultaneously. Limits of agreement between the measurements obtained with the two methods were acceptable. By monitoring the cerebral circulation continuously, increased knowledge of cerebral hemodynamics in preterm infants and sick neonates may be acquired. Improved monitoring of these vulnerable brains during a very sensitive period of brain development may contribute toward preventing brain injuries.

Humberto Belem De Aquino - One of the best experts on this subject based on the ideXlab platform.

  • Cisto dermóide de inclusão congênita sobre a Fontanela anterior: relato de três casos
    Academia Brasileira de Neurologia - ABNEURO, 2003
    Co-Authors: Humberto Belem De Aquino, Carla Ceres Villas De Miranda, Cyro Alves De Britto Filho, Carelli, Edmur Franco, Borges Guilherme
    Abstract:

    Congenital dermoid inclusion cyst over the anterior Fontanel (CDIC) is an uncommon cystic lesion located over the anterior Fontanel. It is a benign and curative lesion and most of the time, can be diagnosed at birth. From 1994 to 2001, three patients were operated with this kind of lesion and after reviewing the literature we found 229 cases and only 6 cases described in Brazil. Our objective in this study is to report three more cases.Cisto dermóide de inclusão congênita sobre a Fontanela anterior (CDIC) é lesão rara localizada na região da Fontanela anterior. Trata-se de lesão benigna e curável que, na maioria das vezes, é diagnosticada no nascimento. De 1994 a 2001, três pacientes foram operados com este tipo de lesão e, através dos dados disponíveis na literatura, verificamos somente 229 casos descritos, apenas 6 descritos no Brasil, o que nos motivou a registrar mais três casos

  • Congenital dermoid inclusion cyst over the anterior Fontanel: report of three cases Cisto dermóide de inclusão congênita sobre a Fontanela anterior: relato de três casos
    Academia Brasileira de Neurologia (ABNEURO), 2003
    Co-Authors: Humberto Belem De Aquino, Carla Ceres Villas De Miranda, Cyro Alves De Britto Filho, Edmur Franco Carelli, Guilherme Borges
    Abstract:

    Congenital dermoid inclusion cyst over the anterior Fontanel (CDIC) is an uncommon cystic lesion located over the anterior Fontanel. It is a benign and curative lesion and most of the time, can be diagnosed at birth. From 1994 to 2001, three patients were operated with this kind of lesion and after reviewing the literature we found 229 cases and only 6 cases described in Brazil. Our objective in this study is to report three more cases.Cisto dermóide de inclusão congênita sobre a Fontanela anterior (CDIC) é lesão rara localizada na região da Fontanela anterior. Trata-se de lesão benigna e curável que, na maioria das vezes, é diagnosticada no nascimento. De 1994 a 2001, três pacientes foram operados com este tipo de lesão e, através dos dados disponíveis na literatura, verificamos somente 229 casos descritos, apenas 6 descritos no Brasil, o que nos motivou a registrar mais três casos