Potencials evocats auditius neurògens vestibulars que precedeixen l'ona n3 en pacients amb hipoacúsia neurosensorial profunda

Els potencials evocats auditius de tronc cerebral (PEATC) aplicats als pacients amb una hipoacúsia neurosensorial profunda (HNSP) no mostren resposta coclear però en el seu lloc pot aparèixer una ona electronegativa, la N3, originada a la via nerviosa vestibular. Kato T. et al. van anomenar, en un peu d’imatge del seu article publicat el 1998, dues ones electropositives de menor voltatge que precedien a la N3. No tenim constància en la literatura científica d’estudis sobre la consistència i el significat d’aquestes dues ones que anomenarem p1 i p2, “p” per ser electropositives i “1” o “2” per la latència mitjana d’aparició (en milisegons). Aquesta tesi parteix d’una descripció inicial de les ones p1 i p2 observades durant la realització d’uns PEATC a 10 pacients amb HNSP. Aquesta caracterització de les ones permet plantejar unes noves condicions d’estimulació i registre, que anomenem test PEANV-N3, per a una millor obtenció de la p1 i p2. S’aplica el test PEANV-N3 a 30 pacients amb HNSP (20 amb ona N3 i 10 sense N3 en els PEATC) i es descriuen les ones p1, p2 i N3. Es compara l’aparició d’aquestes ones amb la presència o absència de potencials evocats miògens vestibulars cervicals, el test electrofisiològic més utilitzat per estudiar el sistema vestibular d’origen sacular. Les ones p1 i p2 presenten una alta consistència amb la N3 i molt probablement són potencials evocats neurògens vestibulars originats a les porcions més distals de la mateixa via nerviosa vestibular que genera la N3. El test PEANV-N3 permet una millor identificació de les ones p1 i p2 sense alterar-ne la morfologia en comparació a l’estudi de PEATC. Els PEMVc i el PEANV-N3 presenten una bona correlació quant a la presència o absència de resposta electrofisiològica evocada.Los potenciales evocados auditivos de tronco cerebral (PEATC) aplicados en pacientes con una hipoacusia neurosensorial profunda (HNSP) no muestran respuesta coclear pero en su lugar pude aparecer una onda electronegativa, la N3, originada en la vía nerviosa vestibular. Kato T. et al. nombraron, en un pie de imagen de su artículo publicado en 1998, dos ondas electropositivas de menor voltaje que precedían la N3. No tenemos constancia en la literatura científica de estudios sobre la consistencia y el significado de estas dos ondas que llamaremos p1 y p2, “p” por ser electropositivas y “1” o “2” por su latencia media de aparición (en milisegundos). Esta tesis parte de una descripción inicial de las ondas p1 y p2 observadas durante la realización de unos PEATC a 10 pacientes con HNSP. Esta caracterización de las ondas permite plantear unes nuevas condiciones de estimulación y registro, que denominaremos test PEANV-N3, para una mejor obtención de la p1 y p2. A continuación, se aplica el test PEANV-N3 a 30 pacientes con HNSP (20 con onda N3 y 10 sin N3 en los PEATC) y se describen las ondas p1, p2 y N3. Se compara la aparición de estas ondas con la presencia o ausencia de potenciales evocados miógenos vestibulares cervicales (PEMVc), el test electrofisiológico más utilizado para estudiar el sistema vestibular de origen sacular. Las ondas p1 i p2 presentan una alta consistencia con la N3 y probablemente son potenciales evocados neurógenos vestibulares originados en las porciones más distales de la misma vía nerviosa vestibular que genera la N3. El test PEANV-N3 permite una mejor identificación de las ondas p1 y p2 sin alterar su morfología en comparación al estudio con PEATC. Existe una buena correlación entre los PEMVc y los PEANV-N3 en cuanto a la presencia o ausencia de respuesta electrofisiológica evocada

Anatomical and functional brain approach along short abrupt changes in G-levels

To conduct experiments under abrupt changes in g-levels, a single-engine aerobatic aircraft has been used, providing 6-8 seconds of reduced gravity, preceded and followed by 5-7 seconds of hypergravity periods. Due to the specific conditions of the flight and previous findings [1], the hypothesis of the present work lies on the idea that some sensory inputs could have a notorious effect on brain final responses when gravity is altered. Therefore, this study focuses on the evaluation of such hypothesis, based on the analysis of the evolution in time of intracranial activity of limbic, visual and auditory cortices. Five subjects (N=5, age 41¿14 years) have flown in parabolic flight with their eyes both open and closed. Electroencephalogram signals were recorded with an Emotive Epoc headset, synchronized with a triaxial accelerometer. The intracranial brain bioelectric activity (standardized current density) throughout the parabola, was calculated by applying Standard Low Resolution Brain Electromagnetic Tomography, and it was analyzed for the limbic, visual and auditory cortices. Intracranial activity of the Temporal, Parietal and Occipital lobes were carried out as well in order to compare the different periods/phases of the flight. Results detected a lower brain activity during the hypogravity phase in all lobes and cortices, only in the case of open eyes. The bioelectrical brain activity along the parabola showed similar patterns in all lobes and cortices, when visual inputs are highlighted. Suppressing the sight, two major behaviors were detected in brain activity: one for temporal lobe and auditory cortex, and second one for the rest of the lobes and visual cortex. It Seemed that, flying with closed eyes, other sensory stimuli were enhanced, in this case the auditory cortex. To confirm the validity of the results two-way ANOVA (factors lobe/phases) and Fisher post hoc test have been applied on mean intracranial activity values in all cases. Spectral entropy evolution in time has been considered as a fast indicator of the sudden extracranial brain activity variation during short g-changes. For open eyes, spectral entropy values indicated a slight decrease at the onset of the hypogravity phase, whereas in case of closed eyes, this change was detected in the last seconds of the parabola, even though these fluctuations were statistically non-significant. Results suggest that some of the sensory inputs can indeed have an impact on brain final response, when gravity conditions are altered.Peer ReviewedPostprint (published version

Evaluation of the Beam-F3 method for locating the F3 position from the 10–20 international system

Electromagnetic brain transcranial stimulation techniques have emerged to treat certain pathologies that require precise anatomical localization in the scalp to access the underlying cortical targets. For example, repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for major depressive disorder when targeted at the dorsolateral prefrontal cortex (DLPFC) [[1],[2]]. The 10–20 international system of electrode placement has been increasingly applied to locate the DLPFC, allowing the placement of a stimulation device above the F3 position. The Beam-F3 method [[3]] is commonly used by clinicians for targeting this area of the brain [[4]]. Advantages of this method include its cost-effectiveness and its ease of implementation, as it does not require neuronavigational systems for target localization.Peer ReviewedPostprint (published version

Comparison of electrode position marking procedures on the cranial surface

The study aimed to compare the conventional method of electrode marking with a new system, EPlacement, to improve accuracy and reduce the time burden on health care professionals. Ten health care professionals marked mannequin heads and adult volunteers using both methods. Time, accuracy, and usability of each method were analyzed. Three neurophysiological diagnostic tests were performed on mannequin heads: reversal pattern visual evoked potential (three electrodes required); somatosensory evoked potentials from the upper and lower extremities (five electrodes required); and standard intraoperative neurophysiological monitoring for spine surgery (nine electrodes required). Precision scanning of the mannequins with structured light and a printed hull were used to determine the actual locations of the electrodes of the 10/20 system. The new method based on the EPlacement device represents an improvement on conventional tape measure (TM) marking and may be considered within the group of advanced methods such as navigation systems since it leads to improvements of 34% (1.7 mm) for electrode positions in the Nasion-Inion and Left tragus–Right tragus lines and 77% (12.5 mm) for electrode positions using the approximate method. It reduces the time spent per test by an average of 1 min compared to the TM method. Health care staff survey results show a positive feedback regarding usability of the new method. The study showed that the EPlacement device improves accuracy, reduces time, and is easy to use compared to the conventional method of electrode marking. The EPlacement method can facilitate the complex task of electrode marking and ultimately contribute to improved patient outcomes. It has the potential to be widely accepted and implemented in clinical practice.We would like to thank the collaborating health care staff of the Clinical Neurophysiology Service at HUSJR and Ismael Ávila for their support with the clinical research plan. The projects that led to these results received funding from “la Caixa” Foundation under grant agreements LCF/TR/CI21/52650005 and LCF/TR/CC22/52500009 and from Research to Business call R2B2021-02, co-funded by the URV and the European Regional Development Fund (ERDF).Peer ReviewedPostprint (published version

Analysis of a new tool for electrode positioning on the scalp according to the international 10/20 system

The emergence of non-invasive electromagnetic brain stimulation techniques, together with the improvement of electrophysiological recordings, has led to the need to increase the precision of the localization of cranial points close to their cortical target. In the clinical practice, the most common technique for locating there points on the scalp is the International 10/20 system and tape measure and a marker pen are used to carry out the marking process, before the placement of the electrodes. In this study, we have compared the marking for different electrophysiological tests between the conventional method and a new method based on the EPlacement device. The comparison was made taking into account the time spent on each test, the mean distance error per electrode, the direction of the error using the coordinate sign and, finally, a survey of healthcare staff to get their opinions on the 1S-EP and 2S-EP variants of EPlacement. The study involved 10 healthcare workers, 5 of whom had experience in conventional marking and 5 had experience in using the EPlacement device. 90 markings on dummies and 10 markings on volunteers were performed. Once each marking was completed on the dummies, the distances between the experimental points (marked with the EPlacement and tap measure) and the reference positions from 10/20 system determined by a 3D printed template were measured. The results show that with EPlacement, marking accuracy is increased, marking time is reduced, and healthcare personnel is receptive to adopting this technology.We would like to thank the collaborating healthcare staff of the Clinical Neurophysiology Service of the Hospital Universitari Sant Joan de Reus and Ismael Ávila for their support in the clinical research plan. This project has obtained funding from the Research to Business call (R2B2021-02), co-funded by the URV and the European Regional Development Fund (ERDF).Postprint (published version

Knowledge extraction from raw data in water networks: application to the Barcelona supramunicipal water transport network

Critical Infrastructure Systems (CIS) such as the case of potable water transport network are complex large-scale systems, geographically distributed and decentralized with a hierarchical structure, requiring highly sophisticated supervisory and real-time control (RTC) schemes to ensure high performance achievement and maintenance when conditions are non-favorable due to e.g. sensor malfunctions (drifts, offsets, problems of batteries, communications problems,...). Once the data are reliable, a process to transform these validated data into useful information and knowledge is key for the operating plan in real time (RTC). And moreover, but no less important, it allows extracting useful knowledge about the assets and instrumentation (sectors of pipes and reservoirs, flowmeters, level sensors, ...) of the network for short, medium and large term management plans. In this work, an overall analysis of the results of the application of a methodology for sensor data validation/reconstruction to the ATLL water network in the city of Barcelona and the surrounding metropolitan area since 2008 until 2013 is described. This methodology is very important for assessing the economic and hydraulic efficiency of the network.Peer ReviewedPostprint (published version

A Computational Efficient Nyquist Shaping Approach for Short-Reach Optical Communications

[EN] Recently, Half-Cycle Nyquist Subcarrier Modulation (HC-SCM) was proposed to achieve high spectral efficiency in intensity-modulator direct-detection optical links. This paper shows that the HC-SCM scheme has a high computational load and proposes the rational Oversampled Subcarrier Modulation (OVS-SCM) as a computational efficient alternative that, furthermore, improves the spectral efficiency. The presented experimental results show that our 256-QAM proposal allows to transmit below the hard-decision forward error correction, with a throughput of 17.8 Gb/s in a 2.5 GHz bandwidth, and a spectral efficiency of 7.2 b/s/Hz, through 20 km of single-mode optical fiber.This work was supported by the Spanish Ministerio de Economia y Competitividad and FEDER under the Grant TEC2015-70858-C2-2-R and Grant RTI2018-101658-B-I00.Pérez Pascual, MA.; Bruno, JS.; Almenar Terre, V.; Valls Coquillat, J. (2020). A Computational Efficient Nyquist Shaping Approach for Short-Reach Optical Communications. Journal of Lightwave Technology (Online). 38(7):1651-1658. https://doi.org/10.1109/JLT.2019.2961506S1651165838

Moduli spaces and formal operads

Let Mg,l be the moduli space of stable algebraic curves of genus g with l marked points. With the operations which relate the different moduli spaces identifying marked points, the family (Mg,l)g,l is a modular operad of projective smooth Deligne-Mumford stacks, M. In this paper we prove that the modular operad of singular chains C?(M;Q) is formal; so it is weakly equivalent to the modular operad of its homology H?(M;Q). As a consequence, the “up to homotopy” algebras of these two operads are the same. To obtain this result we prove a formality theorem for operads analogous to Deligne-Grifiths-Morgan-Sullivan formality theorem, the existence of minimal models of modular operads, and a characterization of formality for operads which shows that formality is independent of the ground field

Monoidal functors, acyclic models and chain operads

We prove that for a topological operad P the operad of oriented cubical chains, Cord ¤ (P), and the operad of singular chains, S¤(P), are weakly equivalent. As a consequence, Cord ¤ (P;Q) is formal if and only if S¤(P;Q) is formal, thus linking together some formality results spread in the literature. The proof is based on an acyclic models theorem for monoidal functors. We give di®erent variants of the acyclic models theorem and apply the contravariant case to study the cohomology theories for simplicial sets de¯ned by R-simplicial di®erential graded algebras