Christos Papadelis

Christos Papadelis
Cook Children's Health Care System · Jane and John Justin Neurosciences Center

PhD

About

157
Publications
43,701
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
2,958
Citations
Introduction
I am a translational researcher aiming to better understand neurological and behavioral pediatric disorders in order to aid prompt and precise diagnosis and treatment. To achieve my main goal, I elaborate and integrate findings from several neuroimaging methods and tools, such as MEG, high-density EEG, TMS, and DTI. I dedicate my research to the promise of my institution to improve the health of every child in our region through the prevention and treatment of illness, disease, and injury.
Additional affiliations
December 2019 - present
TCU and UNTHSC School of Medicine
Position
  • Professor
September 2019 - present
Cook Children's Health Care System
Position
  • Managing Director
September 2019 - present
University of Texas at Arlington
Position
  • Professor (Associate)
Education
January 2001 - January 2005
Aristotle University of Thessaloniki
Field of study
  • Medical Informatics
January 1998 - January 2001
Aristotle University of Thessaloniki
Field of study
  • Medical Informatics
January 1992 - January 1998
Aristotle University of Thessaloniki
Field of study
  • Electrical Engineering

Publications

Publications (157)
Article
Objective In patients with medically refractory epilepsy (MRE), interictal ripples (80‐250 Hz) are seen in large brain areas whose resection may be unnecessary for seizure‐freedom. This limits their utility as epilepsy biomarkers for surgery. We assessed the spatiotemporal propagation of interictal ripples on intracranial electroencephalography (iE...
Article
Full-text available
Objective: To evaluate the accuracy and clinical utility of conventional 21-channel EEG (conv-EEG), 72-channel high-density EEG (HD-EEG) and 306-channel MEG in localizing interictal epileptiform discharges (IEDs). Methods: Twenty-four children who underwent epilepsy surgery were studied. IEDs on conv-EEG, HD-EEG, MEG and intracranial EEG (iEEG)...
Article
Full-text available
Objective: To assess the ability of high-density Electroencephalography (HD-EEG) and magnetoencephalography (MEG) to localize interictal ripples, distinguish between ripples co-occurring with spikes (ripples-on-spike) and independent from spikes (ripples-alone), and evaluate their localizing value as biomarkers of epileptogenicity in children with...
Article
Full-text available
Autism spectrum disorder (ASD) is characterized by social deficits and atypical facial processing of emotional expressions. The underlying neuropathology of these abnormalities is still unclear. Recent studies implicate cerebellum in emotional processing; other studies show cerebellar abnormalities in ASD. Here, we elucidate the spatiotemporal acti...
Article
Full-text available
Objective Intracranial EEG (icEEG) studies show that interictal ripples propagate across the brain of children with medically refractory epilepsy (MRE) and the onset of this propagation (ripple‐onset‐zone, ROZ) estimates the epileptogenic zone. It is still unknown whether we can map this propagation non‐invasively. The goal of this study is to map...
Article
Full-text available
In drug-resistant focal epilepsy, interictal high-frequency oscillations (HFOs) recorded from intracranial EEG (iEEG) may provide clinical information for delineating epileptogenic brain tissue. The iEEG electrode contacts that contain HFO are hypothesized to delineate the epileptogenic zone; their resection should then lead to postsurgical seizure...
Article
Full-text available
The Human Affectome Project was launched by the non-profit organization Neuroqualia (www.neuroqualia.org) in 2015 with the seemingly impossible goal: To map a psychological process and form possible definitions and working models for affective states and related emotions. Twelve reviews based on emotions, feelings and motivation were written dedica...
Article
Full-text available
Delineation of resected brain cavities on magnetic resonance images (MRIs) of epilepsy surgery patients is essential for neuroimaging/neurophysiology studies investigating biomarkers of the epileptogenic zone. The gold standard to delineate the resection on MRI remains manual slice-by-slice tracing by experts. Here, we proposed and validated a semi...
Article
Full-text available
Objective Delineation of the seizure onset zone (SOZ) is required in children with drug resistant epilepsy (DRE) undergoing neurosurgery. Intracranial EEG (icEEG) serves as gold standard but has limitations. Here, we examine the utility of virtual implantation with electrical source imaging (ESI) on ictal scalp EEG for mapping the SOZ and predict s...
Article
Full-text available
Epilepsy surgery is the most effective therapeutic approach for children with drug resistant epilepsy (DRE). Recent advances in neurosurgery, such as the Laser Interstitial Thermal Therapy (LITT), improved the safety and non-invasiveness of this method. Electric and magnetic source imaging (ESI/MSI) plays critical role in the delineation of the epi...
Conference Paper
Full-text available
Interictal epileptiform discharges (IEDs) serve as sensitive but not specific biomarkers of epilepsy that can delineate the epileptogenic zone (EZ) in patients with drug resistant epilepsy (DRE) undergoing surgery. Intracranial EEG (icEEG) studies have shown that IEDs propagate in time across large ar- eas of the brain. The onset of this propagatio...
Conference Paper
Full-text available
Studies on intracranial electroencephalography (icEEG) recordings of patients with drug resistant epilepsy (DRE) show that epilepsy biomarkers propagate in time across brain areas. Here, we propose a novel method that estimates critical features of these propagations for different epilepsy biomarkers (spikes, ripples, and fast ripples), and assess...
Conference Paper
Full-text available
Children with medically refractory epilepsy (MRE) require resective neurosurgery to achieve seizure freedom, whose success depends on accurate delineation of the epileptogenic zone (EZ). Functional connectivity (FC) can assess the extent of epileptic brain networks since intracranial EEG (icEEG) studies have shown its link to the EZ and predictive...
Article
Full-text available
Introduction Generalized tonic-clonic seizures (GTCS) are associated with elevated electrodermal activity (EDA) and postictal generalized electroencephalographic suppression (PGES), markers that may indicate sudden unexpected death in epilepsy (SUDEP) risk. This study investigated the association of GTCS semiology, EDA, and PGES in children with ep...
Article
Children with hemiplegic cerebral palsy (HCP) often show disturbances of somatosensation. Despite extensive evidence of somatosensory deficits, neurophysiological alterations associated with somatosensory deficits in children with HCP have not been elucidated. Here, we aim to assess phase synchrony within and between contralateral primary (S1) and...
Article
Full-text available
Several noninvasive methods, such as high-density EEG or magnetoencephalography, are currently used to delineate the epileptogenic zone (EZ) during the presurgical evaluation of patients with drug resistant epilepsy (DRE). Yet, none of these methods can reliably identify the EZ by their own. In most cases a multimodal approach is needed. Challengin...
Article
Full-text available
About 30% of children with drug-resistant epilepsy (DRE) continue to have seizures after epilepsy surgery. Since epilepsy is increasingly conceptualized as a network disorder, understanding how brain regions interact may be critical for planning re-operation in these patients. We aimed to estimate functional brain connectivity using scalp EEG and i...
Article
Full-text available
Objective To assess whether ictal electric source imaging (ESI) on low-density scalp EEG can approximate the seizure onset zone (SOZ) location and predict surgical outcome in children with refractory epilepsy undergoing surgery. Methods We examined 35 children with refractory epilepsy. We dichotomized surgical outcome into seizure- and non-seizure...
Article
Full-text available
Objective To assess the utility of interictal magnetic and electric source imaging (MSI and ESI) using dipole clustering in magnetic resonance imaging (MRI)-negative patients with drug resistant epilepsy (DRE). Methods We localized spikes in low-density (LD-EEG) and high-density (HD-EEG) electroencephalography as well as magnetoencephalography (ME...
Article
Full-text available
A term neonate is born with the ability to suck; this neuronal network is already formed and functional by 28 weeks gestational age and continues to evolve into adulthood. Because of the necessity of acquiring nutrition, the complexity of the neuronal network needed to suck, and neuroplasticity in infancy, the skill of sucking has the unique abilit...
Article
Objective The SSADHD Natural History Study was initiated in 2019 to define the natural course and identify biomarkers correlating with severity. Methods The study is conducted by 4 institutions: BCH (US clinical), WSU (bioanalytical core), USF (biostatistical core), and Heidelberg (iNTD), with support from the family advocacy group (SSADH Associat...
Article
Magnetoencephalography (MEG) is a noninvasive neuroimaging technique with increasing applications in pediatric populations. Yet, most of the MEG work on infants, toddlers and children has been performed using systems designed for adults; these systems are suboptimal for pediatric populations. MEG systems designed specifically for pediatric use have...
Article
Full-text available
Activation of Functional Brain Networks in Children With Psychogenic Non-Epileptic Seizures Radmanesh M, Jalili M, Kozlowska K. Front Hum Neurosci. 2020. doi:10.3389/fnhum.2020.00339. Objectives: Psychogenic nonepileptic seizures (PNES) have been hypothesized to emerge in the context of neural networks instability. To explore this hypothesis in chi...
Article
Full-text available
This review paper provides an integrative account regarding neurophysiological correlates of positive emotions and affect that cumulatively contribute to the scaffolding for positive emotions and wellbeing in humans and other animals. This paper reviews the associations among neurotransmitters, hormones, brain networks, and cognitive functions in t...
Chapter
This chapter examines clinical motor mapping with magnetoencephalography (MEG). Motor cortex functional mapping procedures were first conducted by neurosurgeons who famously stimulated their patient’s exposed brain during surgery and then systematically documented the responses observed from the activated muscles of the body. Numerous neuroimaging-...
Article
Full-text available
Objectives Photoplethysmography (PPG) reflects variations of blood perfusion in tissues, which may signify seizure‐related autonomic changes. The aim of this study is to assess the variability of PPG signals and their value in detecting peri‐ictal changes in patients with focal impaired awareness seizures (FIASs). Methods PPG data were recorded us...
Article
Full-text available
Objective Photoplethysmography (PPG) is an optical technique measuring variations of blood perfusion in peripheral tissues. We evaluated alterations in PPG signals in relationship to the occurrence of generalized tonic‐clonic seizures (GTCSs) in patients with epilepsy to evaluate the feasibility of seizure detection. Methods During electroencephal...
Article
Magnetoencephalography (MEG) is a noninvasive neuroimaging technique that measures the electromagnetic fields generated by the human brain. This article highlights the benefits that pediatric MEG has to offer to clinical practice and pediatric research, particularly for infants and young children; reviews the existing literature on adult MEG system...
Article
Full-text available
Objective To localize the seizure onset zone (SOZ) and irritative zone (IZ) using electric source imaging (ESI) on intracranial EEG (iEEG) and assess their clinical value in predicting epilepsy surgery outcome in children with focal cortical dysplasia (FCD). Methods We analyzed iEEG data from 25 children with FCD-associated medically refractory ep...
Conference Paper
Full-text available
Rationale High frequency oscillations (HFOs) are emerging biomarkers of epileptogenicity that are typically investigated with intracranial EEG (iEEG). A major limitation of iEEG, linked to its invasiveness, is that it can only sample a portion of the entire cerebral cortex. Full-head non-invasive tests are often necessary to optimize iEEG placement...
Article
Full-text available
Objective: To determine the relationship between nutritive sucking and microstructural integrity of sensorimotor tracts in newborns with brain injury. Study design: Diffusion imaging was performed in ten newborns with brain injury. Nutritive sucking was assessed using Nfant®. The motor, sensory, and corpus callosum tracts were reconstructed via...
Conference Paper
Full-text available
Introduction: Patients with medically refractory epilepsy (MRE) need surgical resection of the epileptogenic zone (EZ) to gain seizure-freedom. High-frequency oscillations (HFOs, > 80 Hz) are promising biomarkers of the EZ that are typically localized using intracranial electroencephalography (icEEG). The goal of this study was to localize the cor...
Article
Full-text available
Aim: To assess changes in the developmental trajectory of corticospinal tracts (CST) maturation in children with hemiplegic cerebral palsy (HCP). Methods: Neuroimaging data were obtained from 36 children with HCP for both the more affected (MA) and less affected (LA) hemispheres, and, for purposes of direct comparison, between groups, 15 typically...
Article
Children born preterm with periventricular leukomalacia (PVL) demonstrate increased difficulties with tasks requiring visuomotor integration. The visuomotor integration network encompasses brain regions within frontal, parietal, and occipital cortices. Because of their proximity to the lateral ventricle the underlying white matter pathways are at a...
Article
Full-text available
The somatosensory system has a hierarchical organization. Information processing increases in complexity from the contralateral primary sensory cortex to bilateral association cortices and this is represented by a sequence of somatosensory-evoked potentials recorded with scalp electroencephalographies. The mammalian somatosensory system matures ove...
Preprint
Full-text available
The somatosensory system has a hierarchical organization. Information processing increases in complexity from the contralateral primary sensory cortex to bilateral association cortices and this is represented by a sequence of somatosensory-evoked potentials recorded with scalp electroencephalographies. The mammalian somatosensory system matures ove...
Article
Full-text available
Despite extensive literature showing damages in the sensorimotor projection fibers of children with hemiplegic cerebral palsy (HCP), little is known about how these damages affect the global brain network. In this study, we assess the relationship between the structural integrity of sensorimotor projection fibers and the integrity of intergyral ass...
Conference Paper
Full-text available
Rationale For patients with medically refractory epilepsy (MRE), the success of epilepsy surgery depends on the availability of a precise biomarker of epileptogenicity. High-frequency oscillations (HFOs) have emerged as reliable epilepsy biomarkers. Ripple HFOs (>80 Hz) can be seen using magnetoencephalography (MEG) or scalp electroencephalography...
Chapter
Full-text available
Artifacts in Pediatric and Adult Magnetoencephalography (Christos Papadelis, Michel AlHilani, and Phillip L. Pearl) In this chapter, we give examples of ambient and biological artifacts that are encountered in the clinical performance of MEG used for children and adults.
Article
Full-text available
Electrophysiological and functional neuroimaging findings indicate that the neural mechanisms underlying the processing of emotional dimensions (i.e., valence, arousal)constitute a spatially and temporally distributed emotional network, modulated by the arousal and/or valence of the emotional stimuli. We examined the time course and source distribu...
Article
Full-text available
Introduction Epilepsy surgery is a potentially curative treatment for medically refractory epilepsy (MRE). The goal of epilepsy surgery is the resection of the epileptogenic zone. Before surgery, MEG and scalp EEG are used to estimate the epileptogenic zone noninvasively by localizing the irritative zone (IZ), which is the area where interictal epi...
Article
Full-text available
Introduction Approximately 20–30% of children with epilepsy develop medically refractory epilepsy (MRE), and require surgical resection of the epileptogenic zone for seizure-freedom. High-frequency oscillations (HFOs), recorded with intracranial electroencephalography (iEEG) and separated into ripples (>80 Hz) and fast-ripples (>250 Hz) are new pro...
Article
Full-text available
Introduction: This study evaluates magnetoencephalographic (MEG) spike population as compared with intracranial electroencephalographic (IEEG) spikes using a quantitative method based on distributed source analysis. Methods: We retrospectively studied eight patients with medically intractable epilepsy who had an MEG and subsequent IEEG monitorin...
Article
Full-text available
Infancy is the most critical period in human brain development. Studies demonstrate that subtle brain abnormalities during this state of life may greatly affect the developmental processes of the newborn infants. One of the rapidly developing methods for early characterization of abnormal brain development is functional connectivity of the brain at...
Article
Full-text available
Functional neuroimaging studies argue that sensory deficits in hemiplegic cerebral palsy (HCP) are related to deviant somatosensory processing in the ipsilesional primary somatosensory cortex (S1). A separate body of structural neuroimaging literature argues that these deficits are due to structural damage of the ascending sensory tracts (AST). The...
Article
Full-text available
Over the past three decades, insights into the role of the cerebellum in emotional processing have substantially increased. Indeed, methodological refinements in cerebellar lesion studies and major technological advancements in the field of neuroscience are in particular responsible to an exponential growth of knowledge on the topic. It is timely t...
Article
Neonatal feeding has been traditionally understudied so guidelines and evidence-based support for common feeding practices are limited. A major contributing factor to the paucity of evidence-based practice in this area has been the lack of simple-to-use, low-cost tools for monitoring sucking performance. We describe new methods for quantifying neon...
Article
Full-text available
Problem: Current methods of identifying infants with Neonatal Brain Injury (NBI) may not be sensitive enough to detect in the neonatal period and others are too costly to be used routinely. Study Design: Longitudinal cohort. Expected Outcomes: Demonstrate clear evidence of the association between early abnormalities in feeding performance and und...
Article
Full-text available
Up to a third of patients with epilepsy are medically intractable and need resective surgery. To be successful, epilepsy surgery requires a comprehensive preoperative evaluation to define the epileptogenic zone (EZ), the brain area that should be resected to achieve seizure-freedom. Due to lack of tools and methods that measure the EZ directly, thi...
Article
Full-text available
Neonatal feeding has been traditionally understudied so guidelines and evidence-based support for common feeding practices are limited. A major contributing factor to the paucity of evidence-based practice in this area has been the lack of simple-to-use, low-cost tools for monitoring sucking performance. We describe new methods for quantifying neon...