Andreas M Koupparis

Cyprus Institute of Neurology and Genetics · Clinical Sciences Sector

Objective To assess the utility of EEG-fMRI for epilepsy surgery, we evaluated surgical outcome in relation to the resection of the most significant EEG-fMRI response. Methods Patients with post-operative neuroimaging and follow-up of at least one year were included. In EEG-fMRI responses, we defined as “primary” the cluster with the highest absol...

OBJECTIVE In an attempt to improve postsurgical seizure outcomes for poorly defined cases (PDCs) of pediatric focal epilepsy (i.e., those that are not visible or well defined on 3T MRI), the authors modified their presurgical evaluation strategy. Instead of relying on concordance between video-electroencephalography and 3T MRI and using functional...

The cyclic alternating pattern (CAP) encompasses the pseudo-periodic appearance of synchronized brain waves and rhythms and is considered a regulator of the NREM sleep vigilance level, reflecting sleep instability. To determine the brain regions responsible for this phenomenon, we scored and analyzed sleep fMRI data acquired with simultaneous EEG (...

Background Sleep EEG organization is revealed by sleep scoring, a time-consuming process based on strictly defined visual criteria. New method We explore the possibility of sleep scoring using the whole-night time-frequency analysis, termed hypnospectrogram, with a computer-assisted K-means clustering method. Results Hypnograms were derived from...

To investigate the spatiotemporal course of interictal spikes in Panayiotopoulos syndrome (PS), and in particular whether seemingly independent extra-occipital spikes are truly autonomous or secondary, triggered by occipital spikes. Seven children with the most representative interictal spike patterns on visual analysis were studied. Five had a sin...

Background: Electroencephalogram (EEG) biomarkers with adequate sensitivity and specificity to reflect the brain’s health status can become indispensable for health monitoring during prolonged missions in space. The objective of our study was to assess whether the basic features of the posterior dominant rhythm (PDR) change under microgravity condi...

Simultaneous electroencephalography–functional MRI (EEG‐fMRI) is a unique and noninvasive method for epilepsy presurgical evaluation. When selecting voxels by null‐hypothesis tests, the conventional analysis may overestimate fMRI response amplitudes related to interictal epileptic discharges (IEDs), especially when IEDs are rare. We aimed to estima...

Epilepsy is a highly heritable disorder affecting over 50 million people worldwide, of which about one-third are resistant to current treatments. Here we report a multi-ancestry genome-wide association study including 29,944 cases, stratified into three broad categories and seven subtypes of epilepsy, and 52,538 controls. We identify 26 genome-wide...

Purpose Amyloid-β (Aβ) peptides, the main component of amyloid plaques found in the Alzheimer's disease (AD) brain, are implicated in its pathogenesis, and are considered a key target in AD therapeutics. We herein propose a reliable strategy for non-invasively delivering a specific anti-Aβ antibody in a mouse model of AD by microbubbles-enhanced Fo...

Gap junctions (GJs) are specialized transmembrane channels assembled by two hemi-channels of six connexin (Cx) proteins that facilitate neuroglial crosstalk in the central nervous system (CNS). Previous studies confirmed the crucial role of glial GJs in neurodegenerative disorders with dementia or motor dysfunction including Alzheimer’s disease (AD...

Objectives: Accurate delineation of the seizure-onset zone (SOZ) in focal drug-resistant epilepsy often requires stereo-electroencephalography (SEEG) recordings. We aimed at: (1) proposing a truly objective and quantitative comparison between electro-encephalography/magnetoencephalography (EEG/MEG) source-imaging (EMSI), EEG/functional MRI (EEG/fM...

Objective This work investigates the spatial distribution in time of generalized ictal spikes in the typical absences of childhood absence epilepsy (CAE). Methods We studied twelve children with CAE, who had more than two typical absences during their routine video-EEG. Seizures were identified, and ictal spikes were marked over the maximum electr...

During Non-Rapid Eye Movement sleep (NREM) the brain is relatively disconnected from the environment, while connectedness between brain areas is also decreased. Evidence indicates, that these dynamic connectivity changes are delivered by microstructural elements of sleep: short periods of environmental stimuli evaluation followed by sleep promoting...

Acknowledgements References 1. Halász P. The K-complex as a special reactive sleep slow wave - A theoretical update. Sleep Med Rev. 2015 Oct 8;29:34-40. 2. Kokkinos V, Kostopoulos GK. Human non-rapid eye movement stage II sleep spindles are blocked upon spontaneous K-complex coincidence and resume as higher frequency spindles afterwards. J Sleep Re...

Consciousness has dual aspects to the dimensions of wakefulness (arousal) and awareness. Wakefulness corresponds to the level of consciousness, and awareness is regarded as the content of consciousness. Usually, these two components of consciousness are positively correlated. During Non-Rapid Eye Movement (NREM) sleep however, the brain is consider...

The purpose of this study was to detect one of the constituent brain waveforms in electroencephalography (EEG), the K-complex (KC). The role and significance of the KC include its engagement in information processing, sleep protection, and memory consolidation [1]. The method applies a two-step methodology in which first all the candidate KC waves...

The EEG in childhood absence epilepsy (CAE) may contain focal and generalised spike-wave discharges (SWDs) with focal, mainly frontal, "lead-in". The term "frontal absence" has been used to imply fast, secondary, 3-Hz generalisation from occult frontal foci with potential impact on clinical EEG interpretation and syndrome classification. The aim of...

NREM sleep is characterized by K-complexes (KCs), over the negative phase of which we identified brief activity in the theta range. We recorded high resolution EEG of whole-night sleep from seven healthy volunteers and visually identified 2nd and 3rd stage NREM spontaneous KCs. We identified three major categories: (1) KCs without intra-KC-activity...

K-complexes and sleep spindles often grouped together characterize the second stage of NREM sleep and interest has been raised on a possible interaction of their underlying mechanisms. The reported inhibition of spindles power for about 15 seconds following evoked K-complexes has implications on their role in arousal. Our objective was to assess th...

Introduction. The involvement of thalamocortical networks in the benign absence epilepsy syndrome of childhood is a debated issue. Aim. To investigate qualitative and quantitative features of sleep spindles following a treated childhood ab- sence epilepsy (CAE) case. Material and Methods. Video-EEG (vEEG) was used to record the whole-night sleep of...

This study introduces a complementary tool for the description and evaluation of human sleep. The nocturnal sleep electroencephalographic (EEG) time-frequency analysis (TFA) plot (hypnospectrogram for short) is hereby proposed as a means to visualize both the macroscopic and the microscopic architecture of human sleep. It provides the ability to co...

In this paper, we present the clinical evaluation of HEPAR, an intelligent system for hepatitis prognosis and liver transplantation decision support in an UCI medical database. The prognosis process, linguistic variables and their values were modeled based on expert’s knowledge the statistical analysis of the records of patients from the existed me...