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Valerio et al. Neuroimmunol Neuroinflammation 2021;8:42-9 Neuroimmunology
DOI: 10.20517/2347-8659.2020.30 and Neuroinflammation

Case Report Open Access

The relation between lesions and localization of
sources of slow biphasic complexes in encephalitis

Massimo Valerio, Stefano Rivera, Luca Mesin

Mathematical Biology & Physiology, Department of Electronics and Telecommunications, Politecnico di Torino, Turin 10129,
Italy.
Correspondence to: Prof. Luca Mesin, Mathematical Biology & Physiology, Department of Electronics and Telecommunications,
Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin 10129, Italy. E-mail: luca.mesin@polito.it
How to cite this article: Valerio M, Rivera S, Mesin L.The relation between lesions and localization of sources of slow biphasic
complexes in encephalitis. Neuroimmunol Neuroinflammation 2021;8:42-9. http://dx.doi.org/10.20517/2347-8659.2020.30
Received: 11 Apr 2020 First Decision: 28 May 2020 Revised: 12 Jun 2020
Accepted: 28 Jun 2020 Fisrt online: 15 Aug 2020 Published: 21 Mar 2021

Academic Editor: Mercè Falip Copy Editor: Cai-Hong Wang Production Editor: Jing Yu

Abstract
Slow biphasic complexes (SBC) were found in the electroencephalogram (EEG) of patients with inflammations of
the brain. We have developed an automated method to identify them and proved that they represent a sensitive
marker of the severity of encephalitis. Here we focus on another property of SBCs, i.e., the localization of their
sources. We present two encephalitic patients, showing lesions in the magnetic resonance images, which are
either spread in the brain or focused on the left hemisphere, respectively. Applying a source localization algorithm
to the identified SBCs, we found either a diffused or a left-focused distribution, respectively. This result further
suggests a relation between neuroinflammation and appearance of SBCs, indicating that their distribution reflects
in part the localization of brain lesions. This promising result extends the information that can be extracted from
EEG, promoting the reduction of expensive or invasive measurements in encephalitic patients.

Keywords: EEG, encephalitis, slow biphasic complex, source localization

INTRODUCTION
Encephalitis is an inflammatory process of the cerebral parenchyma associated with neurological
[2]
[1]
dysfunctions , which requires prompt diagnosis and intervention . It is caused mainly by infectious
[3,4]
diseases or immune disorders, cancer, and vascular problems . It can have different progressions (acute,

© The Author(s) 2021. Open Access This article is licensed under a Creative Commons Attribution 4.0
International License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use,
sharing, adaptation, distribution and reproduction in any medium or format, for any purpose, even commercially, as long
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