Egill Axfjord Fridgeirsson

Egill Axfjord Fridgeirsson
Academisch Medisch Centrum Universiteit van Amsterdam | AMC · Department of Psychiatry

M.sc in BIomedical Engineering

About

34
Publications
6,785
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
492
Citations
Additional affiliations
January 2017 - January 2021
Academisch Medisch Centrum Universiteit van Amsterdam
Position
  • PhD Student
June 2010 - September 2014
National University Hospital of Iceland
Position
  • Clinical Engineer

Publications

Publications (34)
Article
Background Widely used psychotropic medications obsessive-compulsive disorder (OCD) may change the volumes of subcortical brain structures, and differently in children vs. adults. We measured subcortical volumes cross-sectionally in patients finely stratified for age taking various common classes of OCD drugs. Methods The ENIGMA-OCD consortium sam...
Preprint
Background Many dementia prediction models have been developed, but only few have been externally validated, which hinders clinical uptake and may pose a risk if models are applied to actual patients regardless. Replicating and externally validating a prediction model is a difficult task, where we mostly rely on the completeness of model reporting...
Article
Full-text available
Objective: This systematic review aims to assess how information from unstructured text is used to develop and validate clinical prognostic prediction models. We summarize the prediction problems and methodological landscape and determine whether using text data in addition to more commonly used structured data improves the prediction performance....
Article
Full-text available
Neurosurgical interventions including deep brain stimulation (DBS) and capsulotomy have been demonstrated effective for refractory obsessive-compulsive disorder (OCD), although treatment-shared/-specific network mechanisms remain largely unclear. We retrospectively analyzed resting-state fMRI data from three cohorts: a cross-sectional dataset of 18...
Presentation
Full-text available
Background: A new generation of deep brain stimulation (DBS) stimulators hold promise for closed loop stimulation, with personalized adaptive stimulation in response to biological signals. This approach requires network biomarkers that indicate when stimulation is needed. We present data on intracranial and extracranial electrophysiological recordi...
Article
Full-text available
Objective Develop and validate models that predict mortality of patients diagnosed with COVID-19 admitted to the hospital. Design Retrospective cohort study. Setting A multicentre cohort across 10 Dutch hospitals including patients from 27 February to 8 June 2020. Participants SARS-CoV-2 positive patients (age ≥18) admitted to the hospital. Mai...
Preprint
Full-text available
Deep brain stimulation is a treatment option for patients with refractory obsessive-compulsive disorder. A new generation of stimulators hold promise for closed loop stimulation, with adaptive stimulation in response to biological signals Here we aimed to discover a suitable biomarker in the ventral striatum in patients with obsessive compulsive di...
Article
Full-text available
The clinical effect of electroconvulsive therapy (ECT) is mediated by eliciting a generalized seizure, which is achieved by applying electrical current to the head via scalp electrodes. The anatomy of the head influences the distribution of current flow in each brain region. Here, we investigated whether individual differences in simulated local el...
Preprint
Objective: Develop and validate models that predict mortality of SARS-CoV-2 infected patients admitted to the hospital. Design: Retrospective cohort study Setting: A multicenter cohort across ten Dutch hospitals including patients from February 27 to June 8 2020. Participants: SARS-CoV-2 positive patients (age ≥ 18) admitted to the hospital. Main O...
Article
Full-text available
No diagnostic biomarkers are available for obsessive-compulsive disorder (OCD). Here, we aimed to identify magnetic resonance imaging (MRI) biomarkers for OCD, using 46 data sets with 2304 OCD patients and 2068 healthy controls from the ENIGMA consortium. We performed machine learning analysis of regional measures of cortical thickness, surface are...
Article
Full-text available
No diagnostic biomarkers are available for obsessive-compulsive disorder (OCD). Here, we aimed to identify magnetic resonance imaging (MRI) biomarkers for OCD, using 46 data sets with 2304 OCD patients and 2068 healthy controls from the ENIGMA consortium. We performed machine learning analysis of regional measures of cortical thickness, surface are...
Article
Full-text available
Objective: Attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and obsessive-compulsive disorder (OCD) are common neurodevelopmental disorders that frequently co-occur. The authors sought to directly compare these disorders using structural brain imaging data from ENIGMA consortium data. Methods: Structural T1-weight...
Article
Full-text available
Deep brain stimulation is effective for patients with treatment-refractory obsessive-compulsive disorder. Deep brain stimulation of the ventral anterior limb of the internal capsule rapidly improves mood and anxiety with optimal stimulation parameters. To understand these rapid effects, we studied functional interactions within the affective amygda...
Preprint
Full-text available
Deep brain stimulation (DBS) is effective for patients with treatment‐refractory obsessive‐compulsive disorder. DBS of the ventral anterior limb of the internal capsule (vALIC) rapidly improves mood and anxiety with optimal stimulation parameters. To understand these rapid effects of vALIC‐DBS, we studied functional interactions within the affectiv...
Chapter
Major depressive disorder (MDD) is a highly prevalent condition and present first-line treatment options are inadequate. Among nonpharmacological treatment alternatives, noninvasive brain stimulation shows tremendous promise. There are two approved brain stimulation techniques for the treatment of MDD: electroconvulsive therapy (ECT) and repetitive...
Article
Full-text available
BACKGROUND Lateralized dysfunction has been suggested in obsessive-compulsive disorder (OCD). However, it is currently unclear whether OCD is characterized by abnormal patterns of brain structural asymmetry. Here we carried out what is by far the largest study of brain structural asymmetry in OCD. METHODS We studied a collection of 16 pediatric dat...
Presentation
Background: Lateralized dysfunction has been suggested in obsessive-compulsive disorder (OCD). However, it is currently unclear whether OCD is characterized by abnormal patterns of brain structural asymmetry. Here we carried out what is by far the largest study of brain structural asymmetry in OCD. Methods: We studied a collection of 16 pediatri...
Article
Full-text available
Objective: Brain imaging communities focusing on different diseases have increasingly started to collaborate and to pool data to perform well-powered meta- and mega-analyses. Some methodologists claim that a one-stage individual-participant data (IPD) mega-analysis can be superior to a two-stage aggregated data meta-analysis, since more detailed co...
Article
Abstract Objective: Brain imaging studies of structural abnormalities in OCD have yielded inconsistent results, partly because of limited statistical power, clinical heterogeneity, and methodological differences. The authors conducted meta- and mega-analyses comprising the largest study of cortical morphometry in OCD ever undertaken. Method: T1-we...
Article
Objective To define how fontanels affect scalp EEG potentials in neonates. Method Realistic finite element method head models were generated with and without fontanels. The electrical activity of the whole cortex was simulated using distributed 54620 concurrently active cortical dipoles with a uniform random distribution of current densities (0-...
Article
Full-text available
The dura layer which covers the brain is less conductive than the CSF (cerebrospinal fluid) and also more conductive than the skull bone. This could significantly influence the flow of volume currents from cortex to the scalp surface which will also change the magnitude and spatial profiles of scalp potentials. This was examined with a 3-D finite e...
Article
Full-text available
Computer simulation and modelling of the human body and its behaviour are very useful tools in situations where it is either too risky to perform an invasive procedure or too costly for in vivo experiments or simply impossible for ethical reasons. In this paper we describe a method to model the electrical behaviour of human brain from segmented MR...
Conference Paper
Full-text available
Our objective was to examine how scalp potentials and magnetic fields change due to a partial stroke in the left or right side of the brain. This was simulated with a finite element method (FEM) model of an adult subject.
Conference Paper
Full-text available
nngangur: Heilliðun í mjöðm (TPM) er gerð með eða án sements. Vegna skorts á áreiðanlegum viðmiðunarreglum um hvort sjúklingur eigi að fá heillið með eða án sements var hafin klínísk og verkfræðileg rannsókn. Hér er kynntur verkfræðihluti rannsóknarinnar með frumniðurstöðum beinstyrksgreiningar og álagsmælingar á lærleggsbeini og ígræði. Efniviður...
Article
Full-text available
Computer simulation and modelling of the human body and its behaviour are very useful tools in situations where it is either too risky to perform an invasive procedure or too costly for in vivo experiments or simply impossible for ethical reasons. In this paper we describe a method to model the electrical behaviour of human brain from segmented MR...
Conference Paper
Full-text available
In this paper, we describe a method to analyze facial muscles and display structural changes occurring under normal and pathological conditions from segmented MR images. Orbicularis oculi and zygomaticus muscles are isolated from the surrounding tissues and their gray values analyzed. We use 3 Tesla magnetic resonance imaging (MRI) and special imag...
Article
Full-text available
In this paper, we describe a method to analyze facial muscles and display structural changes occurring under normal and pathological conditions from segmented MR images. Orbicularis oculi and zygomaticus muscles are isolated from the surrounding tissues and their gray values analyzed. We use 3 Tesla magnetic resonance imaging (MRI) and special imag...
Article
Full-text available
Muscle tissue composition accounting for the relative content of muscle fibres and intramuscular adipose and loose fibrous tissues can be efficiently analyzed and quantified using images from spiral computed tomography (S-CT) technology and the associated distribution of Hounsfield unit (HU) values. Muscle density distribution, especially when incl...

Network

Cited By