Vangelis Sakkalis

Dr. Vangelis Sakkalis

Research Director Computational BioMedicine Laboratory, Institute of Computer Science, Foundation for Research and Technology – HELLAS, Nikolaou Plastira 100, Vassilika Vouton, P.O Box 1385, GR-70013 Heraklion, Crete, Greece
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Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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7 November 2008 in Journal of NeuroEngineering and Rehabilitation
Verified
Journal Article
Open access
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RGRoberta Grech
Roberta Grech
TCTracey Cassar
Tracey Cassar
JMJoseph Muscat
Joseph Muscat
KCKenneth P Camilleri
Kenneth P Camilleri
SFSimon G. Fabri
Simon G. Fabri
Bart VanrumsteBart Vanrumste
Bart Vanrumste
In this primer, we give a review of the inverse problem for EEG source localization. This is intended for the researchers new in the field to get insight in the state-of-the-art techniques used to find approximate solutions of the brain sources giving rise to a scalp potential recording. Furthermore, a review of the performance results of the different techniques is provided to compare these different inverse solutions. The authors also include the results of a Monte-Carlo analysis which they performed to compare four non parametric algorithms and hence contribute to what is presently recorded in the literature. An extensive list of references to the work of other researchers is also provided.This paper starts off with a mathematical description of the inverse problem and proceeds to discuss the two main categories of methods which were developed to solve the EEG inverse problem, mainly the non parametric and parametric methods. The main difference between the two is to whether a fixed number of dipoles is assumed a priori or not. Various techniques falling within these categories are described including minimum norm estimates and their generalizations, LORETA, sLORETA, VARETA, S-MAP, ST-MAP, Backus-Gilbert, LAURA, Shrinking LORETA FOCUSS (SLF), SSLOFO and ALF for non parametric methods and beamforming techniques, BESA, subspace techniques such as MUSIC and methods derived from it, FINES, simulated annealing and computational intelligence algorithms for parametric methods. From a review of the performance of these techniques as documented in the literature, one could conclude that in most cases the LORETA solution gives satisfactory results. In situations involving clusters of dipoles, higher resolution algorithms such as MUSIC or FINES are however preferred. Imposing reliable biophysical and psychological constraints, as done by LAURA has given superior results. The Monte-Carlo analysis performed, comparing WMN, LORETA, sLORETA and SLF, for different noise levels and different simulated source depths has shown that for single source localization, regularized sLORETA gives the best solution in terms of both localization error and ghost sources. Furthermore the computationally intensive solution given by SLF was not found to give any additional benefits under such simulated conditions.

1 December 2011 in Computers in Biology and Medicine
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Journal Article
Closed access
Vangelis SakkalisVangelis Sakkalis
Vangelis Sakkalis

24 June 2016 in Journal of Medical Internet Research
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Journal Article
Open access
Emmanouil SpanakisEmmanouil Spanakis
Emmanouil Spanakis
SSSilvina Santana
Silvina Santana
Manolis TsiknakisManolis Tsiknakis
Manolis Tsiknakis
Kostas MariasKostas Marias
Kostas Marias
Vangelis SakkalisVangelis Sakkalis
Vangelis Sakkalis
CTChariklia Tziraki-Segal
Chariklia Tziraki-Segal
Journal of Medical Internet Research - International Scientific Journal for Medical Research, Information and Communication on the Internet

17 January 2014 in Sensors
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AHAnna Hristoskova
Anna Hristoskova
Vangelis SakkalisVangelis Sakkalis
Vangelis Sakkalis
GZGeorgios Zacharioudakis
Georgios Zacharioudakis
Manolis TsiknakisManolis Tsiknakis
Manolis Tsiknakis
FTFilip De Turck
Filip De Turck
A major challenge related to caring for patients with chronic conditions is the early detection of exacerbations of the disease. Medical personnel should be contacted immediately in order to intervene in time before an acute state is reached, ensuring patient safety. This paper proposes an approach to an ambient intelligence (AmI) framework supporting real-time remote monitoring of patients diagnosed with congestive heart failure (CHF). Its novelty is the integration of: (i) personalized monitoring of the patients health status and risk stage; (ii) intelligent alerting of the dedicated physician through the construction of medical workflows on-the-fly; and (iii) dynamic adaptation of the vital signs’ monitoring environment on any available device or smart phone located in close proximity to the physician depending on new medical measurements, additional disease specifications or the failure of the infrastructure. The intelligence lies in the adoption of semantics providing for a personalized and automated emergency alerting that smoothly interacts with the physician, regardless of his location, ensuring timely intervention during an emergency. It is evaluated on a medical emergency scenario, where in the case of exceeded patient thresholds, medical personnel are localized and contacted, presenting ad hoc information on the patient’s condition on the most suited device within the physician’s reach.

31 October 2017 in BioMed Research International
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Journal Article
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MOMariam-Eleni Oraiopoulou
Mariam-Eleni Oraiopoulou
ETEleftheria Tzamali
Eleftheria Tzamali
GTGeorgios Tzedakis
Georgios Tzedakis
AVA. Vakis
A. Vakis
JPJ. Papamatheakis
J. Papamatheakis
Vangelis SakkalisVangelis Sakkalis
Vangelis Sakkalis
The application of accurate cancer predictive algorithms validated with experimental data is a field concerning both basic researchers and clinicians, especially regarding a highly aggressive form of cancer, such as Glioblastoma. In an aim to enhance prediction accuracy in realistic patient-specific environments, accounting for both inter- and intratumoral heterogeneity, we use patient-derived Glioblastoma cells from different patients. We focus on cell proliferation using in vitro experiments to estimate cell doubling times and sizes for established primary Glioblastoma cell lines. A preclinically driven mathematical model parametrization is accomplished by taking into account the experimental measurements. As a control cell line we use the well-studied U87MG cells. Both in vitro and in silico results presented support that the variance between tumor staging can be attributed to the differential proliferative capacity of the different Glioblastoma cells. More specifically, the intratumoral heterogeneity together with the overall proliferation reflected in both the proliferation rate and the mechanical cell contact inhibition can predict the in vitro evolution of different Glioblastoma cell lines growing under the same conditions. Undoubtedly, additional imaging techniques capable of providing spatial information of tumor cell physiology and microenvironment will enhance our understanding regarding Glioblastoma nature and verify and further improve our predictability.

20 February 2025 in Pharmaceuticals
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Marios SpanakisMarios Spanakis
Marios Spanakis
ETEleftheria Tzamali
Eleftheria Tzamali
GTGeorgios Tzedakis
Georgios Tzedakis
CKChryssalenia Koumpouzi
Chryssalenia Koumpouzi
Matthew PediaditisMatthew Pediaditis
Matthew Pediaditis
Vangelis SakkalisVangelis Sakkalis
Vangelis Sakkalis
Artificial intelligence (AI) has emerged as a powerful tool in medical sciences that is revolutionizing various fields of drug research. AI algorithms can analyze large-scale biological data and identify molecular targets and pathways advancing pharmacological knowledge. An especially promising area is the assessment of drug interactions. The AI analysis of large datasets, such as drugs’ chemical structure, pharmacological properties, molecular pathways, and known interaction patterns, can provide mechanistic insights and identify potential associations by integrating all this complex information and returning potential risks associated with these interactions. In this context, an area where AI may prove valuable is in the assessment of the underlying mechanisms of drug interactions with natural products (i.e., herbs) that are used as dietary supplements. These products pose a challenging problem since they are complex mixtures of constituents with diverse and limited information regarding their pharmacological properties, especially their pharmacokinetic data. As the use of herbal products and supplements continues to grow, it becomes increasingly important to understand the potential interactions between them and conventional drugs and the associated adverse drug reactions. This review will discuss AI approaches and how they can be exploited in providing valuable mechanistic insights regarding the prediction of interactions between drugs and herbs, and their potential exploitation in experimental validation or clinical utilization.