Sandy Rihana | Université Saint-Esprit de Kaslik / Holy Spirit University of Kaslik (original) (raw)

Papers by Sandy Rihana

BMC medical education, Apr 26, 2024

2017 Fourth International Conference on Advances in Biomedical Engineering (ICABME), 2017

The main causes of highways mortality are fatigue and sleepiness while driving. In this paper, we... more The main causes of highways mortality are fatigue and sleepiness while driving. In this paper, we propose a method to detect the transition between wakefulness and sleepiness states based on driver's brain activity recorded through Electroencephalography (EEG). Our new method uses the Phase Locking Value (PLV)to extract data that are directly related and correlated to the sleepiness. PLV measures changes in the neuronal function. Results show the performance of PLV and its ability to improve the performance of already existing systems.

2016 3rd Middle East Conference on Biomedical Engineering (MECBME), 2016

Before few decades disabled persons were not able to perform daily tasks such as turning the ligh... more Before few decades disabled persons were not able to perform daily tasks such as turning the light on, making a phone call, and even controlling the TV. Disability was an obstacle therefore disabled individuals needed daily monitoring and service. With the evolution of computation power and the progress in neuronal studies, modern technology and science managed to overcome the human disability for example the ability to walk was restored with the help of fully automated prosthetic legs controlled by brain signals.This work aimed to aid the disabled people that are not able to simply grasp a TV remote control to switch the TV on or browse through the channels; therefore a brain machine interface must be implemented. Low cost portable ElectroEncephaloGraph (EEG) system is designed and tested that allow a person to control the TV through his eye blinks. An overall accuracy of 90% has been obtained in testing 5 TV control events. The total price of the prototype did not exceed the 60 USD.

HAL (Le Centre pour la Communication Scientifique Directe), Oct 8, 2008

HAL (Le Centre pour la Communication Scientifique Directe), 2015

In healthy tissue, metabolites are present in steady-state concentrations typical for that specif... more In healthy tissue, metabolites are present in steady-state concentrations typical for that specific tissue. Metabolite concentrations may shift due to stress, functional disturbances, tumors or metabolic diseases. These changes are detectable with MRS, and provide valuable information for both diagnosis and therapeutic surveillance. Various methods have been developed to quantify the metabolite concentrations using methods ranging from the simple integration of spectral peak to complex algorithms. Theory and Methods: The purpose of this work is to develop an analysis system for in vivo NMR spectroscopy for brain metabolites quantification based on continuous wavelet transforms without prior knowledge. Tests are done on both simulated and real in vivo MRS signals using spectroscopic data acquired in 16 healthy subjects (range 20-50) using 3T MR system. Results: Results show that even with the presence of low SNRs and baseline, the proposed method is able to derive the parameters such as the frequencies, the amplitudes and the damping factors of metabolites directly from the raw data and without any beforehand preprocessing or prior knowledge. Conclusion: The CWT analysis has shown to be accurate, robust and in agreement with the time domain fitting method AMARES for the quantification of short echo time in vivo MRS data.

According to some statistics published by Centers for Disease Control and Prevention (CDC), 1 in ... more According to some statistics published by Centers for Disease Control and Prevention (CDC), 1 in 50 people approximately around the world is incapable of achieving some of daily's life activities by his own due to paralysis. Paralysis is the partial or total inability of the human body to perform some movements caused by stroke, spinal cord injury, multiple sclerosis, birth defect, etc. Today, number of paralysis "victims" is increasing dramatically making over 6 million people paralyzed around the world, with some cases were the physical therapy becomes unable to heal. Consequently, Technology has constantly been a major player in a large number of physical therapy applications, and offers many advantages for paralyzed people that the physical therapy is not able to provide. Recently, exoskeleton patient motion aiding technology was introduced in order to supply disabled people and regain mobility. The main goal of this project is to study the Sit-to-Stand and Stand-to-Sit transfer in 10 young healthy subjects. IMU (Inertial Measurement Unit) wearable sensors, more specifically MPU6050 sensors, are used in the performed experiences in order to extract desired raw data such as the acceleration, angular rate and inclination of lower limb different segments including metatarsal, shank and thigh segments and the inclination of the trunk. Thus, ankle, knee and hip joints angles were derived. Furthermore, extracted features are studied, analyzed and used to establish epochs and recognize phases of the Sit-to-Stand gesture based on a number of previous Sit-to-Stand literature of art. This is accomplished using Artificial Neural Network, using different architectures and choosing the best one, which resulted in four main phases: flexion phase, transfer phase, extension phase and stabilization phase. Finally, and using the proper Neural Network with the higher accuracy (92.3% accuracy using the 30 layers architecture), a Sit-to-Stand algorithm is proposed and modeled.

In haematology, developing an automated blood cells types identifications based on microscopic ex... more In haematology, developing an automated blood cells types identifications based on microscopic examination could serve as a software tool for archiving haematology images, for automatic classification and it could help widely the clinicians in their laboratory tasks. This paper presents basic algorithms used in automated blood cell identifications based on microscopic image processing techniques. White blood cell segmentation method, red blood cell segmentation method and classification of basic blood cell types are presented. The promising results are compared with the manual investigation results obtained by the haematologists and experts of the field. A ratio of white blood cells over red blood cells is computed and gives an idea of the clinical diagnosis of the blood smear examined and all the examined samples matched the real clinical diagnostic.

IEEE Transactions on Biomedical Engineering, Jun 1, 2018

The objective of this work is the development of an accurate seizure forecasting algorithm that c... more The objective of this work is the development of an accurate seizure forecasting algorithm that considers brain's functional connectivity for electrode selection. Methods: We start by proposing Kmeans-directed transfer function, an adaptive functional connectivity method intended for seizure onset zone localization in bilateral intracranial EEG recordings. Electrodes identified as seizure activity sources and sinks are then used to implement a seizure-forecasting algorithm on long-term continuous recordings in dogs with naturallyoccurring epilepsy. A precision-recall genetic algorithm is proposed for feature selection in line with a probabilistic support vector machine classifier. Results: Epileptic activity generators were focal in all dogs confirming the diagnosis of focal epilepsy in these animals while sinks spanned both hemispheres in 2 of 3 dogs. Seizure forecasting results show performance improvement compared to previous studies, achieving average sensitivity of 84.82% and time in warning of 0.1. Conclusion: Achieved performances highlight the feasibility of seizure forecasting in canine epilepsy. Significance: The ability to improve seizure forecasting provides promise for the development of EEGtriggered closed-loop seizure intervention systems for ambulatory implantation in patients with refractory epilepsy.

Durant ces dernieres decennies, l'activite electrique uterine origine des contractions menant... more Durant ces dernieres decennies, l'activite electrique uterine origine des contractions menant a l'accouchement constitue une etude de recherche primordiale pour la prevention et pour la detection des accouchements prematures. La modelisation mathematique et la simulation informatique sont devenues des outils indispensables pour la comprehension de differents phenomenes electrophysiologiques afin de predire, et d'agir en cas d'anomalie. Sachant que le controle de l'excitabilite uterine s'avere avoir des consequences therapeutiques importantes, nous avons choisi de debuter le modele a l'echelle cellulaire. L'analyse dynamique de ce modele a permis de montrer l'efficacite de certains traitements tocolytiques tels que les bloqueurs des canaux calciques et les ouvreurs des canaux potassiques. Le controle de la contractilite uterine ne se limite pas au niveau cellulaire mais s'etend aussi au niveau tissulaire. Nous avons demontre comment un modele de propagation biophysique permet de reproduire le couplage electrique reduit entre les cellules en debut de grossesse et le couplage fort et synchronise a l'approche du terme. Cette propagation a permis d'estimer un electromyogramme uterin de surface. Ce travail de these, quoique innovant et interessant reste dans une premiere etape preliminaire. Il en porte en lui de futurs axes de recherches et de developpement pluridisciplinaires prometteurs, dans l'objectif de fournir un modele numerique de l'activite electrique uterine, contribuant a la comprehension de phenomenes physiologiques et a la prediction d'accouchement premature.

Radiotherapy is one of the main cancer treatments. It consists in irradiating tumor cells to dest... more Radiotherapy is one of the main cancer treatments. It consists in irradiating tumor cells to destroy them while sparing healthy tissue. The treatment is planned based on Computed Tomography (CT) and is delivered over fractions during several days. One of the main challenges is replacing patient in the same position every day to irradiate the tumor volume while sparing healthy tissues. Many patient positioning techniques are available. They are both invasive and not accurate performed using tattooed marker on the patient's skin aligned with a laser system calibrated in the treatment room or irradiating using X-ray. Currently systems such as Vision RT use two Time of Flight cameras. Time of Flight cameras have the advantage of having a very fast acquisition rate allows the real time monitoring of patient movement and patient repositioning. The purpose of this work is to test the Microsoft Kinect2 camera for potential use for patient positioning and respiration trigging. This type of Time of Flight camera is non-invasive and costless which facilitate its transfer to clinical practice.

HAL (Le Centre pour la Communication Scientifique Directe), Sep 1, 2006

The uterus is a physiological system consisting of a large number of interacting smooth muscle ce... more The uterus is a physiological system consisting of a large number of interacting smooth muscle cells. The uterine excitability changes remarkably with time, generally quiescent during pregnancy, the uterus exhibits forceful synchronized contractions at term leading to fetus expulsion. These changes characterize thus a dynamical system susceptible of being studied through formal mathematical tools. Multiple physiological factors are involved in the regulation process of this complex system. Our aim is to relate the physiological factors to the uterine cell dynamic behaviors. Taking into account a previous work presented, in which the electrical activity of a uterine cell is described by a set of ordinary differential equations, we analyze the impact of physiological parameters on the response of the model, and identify the main subsystems generating the complex uterine electrical activity, with respect to physiological data.

HAL (Le Centre pour la Communication Scientifique Directe), Jul 1, 2006

HAL (Le Centre pour la Communication Scientifique Directe), Aug 24, 2008

Physics Procedia, 2011

The aim of physiological modeling of the uterine electrical activity generated at cellular level ... more The aim of physiological modeling of the uterine electrical activity generated at cellular level is to understand the main physiological uterine contractile mechanisms, in particular, the propagation mechanisms and their relationship with the uterine EMG signal recorded externally from the abdominal wall of the pregnant women. In this present paper, we model the electrical activity simulated at its cellular level. This model is built in three steps: first we built a model based on the formulation of Hodgkin and Huxley and adapted to the specificities of the uterine cell. The second step was the integration of the cellular model in a two-dimensional propagation model by using the reactiondiffusion equations in order to simulate the propagation of the uterine activity at the tissue level. Finally, a simplified version of the space-time integration of the electrical activity was used to build a first example of the uterine EMG.

IFAC Proceedings Volumes, 2006

The uterine electromyogram (EMG) or electrohysterogram (EHG) could be used to detect a potential ... more The uterine electromyogram (EMG) or electrohysterogram (EHG) could be used to detect a potential risk of preterm delivery in woman by analyzing its frequency content. In this study, we explore the effects of electrodes position, in terms of inactive tissues depth below the recording site and distance of electrodes to the potentials source, on the spectral characteristics of recorded signals. To explore these effects on skeletal muscle EMG and EHG, we used two numerical models but also real EHG. We have been able to notice specific effects in each situation but also cumulative effects. On real EHG, we could see that the main effect concerns the attenuation of high frequencies. Thus, the standardization of the electrode position during recording is a factor of importance.

Medical & Biological Engineering & Computing, Mar 20, 2009

BMC Pregnancy and Childbirth, Jun 1, 2007

Background: The electrical activity of the uterine muscle is representative of uterine contractil... more Background: The electrical activity of the uterine muscle is representative of uterine contractility. Its characterization may be used to detect a potential risk of preterm delivery in women, even at an early gestational stage. Methods: We have investigated the effect of the recording electrode position on the spectral content of the signal by using a mathematical model of the women's abdomen. We have then compared the simulated results to actual recordings. On signals with noise reduced with a dedicated algorithm, we have characterized the main frequency components of the signal spectrum in order to compute parameters indicative of different situations: preterm contractions resulting nonetheless in term delivery (i.e. normal contractions) and preterm contractions leading to preterm delivery (i.e. high-risk contractions). A diagnosis system permitted us to discriminate between these different categories of contractions. As the position of the placenta seems to affect the frequency content of electrical activity, we have also investigated in monkeys, with internal electrodes attached on the uterus, the effect of the placenta on the spectral content of the electrical signals. Results: In women, the best electrode position was the median vertical axis of the abdomen. The discrimination between high risk and normal contractions showed that it was possible to detect a risk of preterm labour as early as at the 27th week of pregnancy (Misclassification Rate range: 11-19.5%). Placental influence on electrical signals was evidenced in animal recordings, with higher energy content in high frequency bands, for signals recorded away from the placenta when compared to signals recorded above the placental insertion. However, we noticed, from pregnancy to labour, a similar evolution of the frequency content of the signal towards high frequencies, whatever the relative position of electrodes and placenta. Conclusion: On human recordings, this study has proved that it is possible to detect, by non-invasive abdominal recordings, a risk of preterm birth as early as the 27th week of pregnancy. On animal signals, we have evidenced that the placenta exerts a local influence on the characteristics of the electrical activity of the uterus. However, these differences have a small influence on premature delivery risk diagnosis when using proper diagnosis tools.

Conference proceedings, Aug 1, 2007

The uterus, usually quiescent during pregnancy, exhibits forceful contractions at term leading to... more The uterus, usually quiescent during pregnancy, exhibits forceful contractions at term leading to delivery. These contractions are caused by the synchronized propagation of electrical waves from the pacemaker cells to its neighbors inducing the whole coordinated contraction of the uterus wall leading to labor. In a previous work, we simulate the electrical activity of a single uterine cell by a set of ordinary differential equations. Then, this model has been used to simulate the electrical activity propagation. In the present work, the uterine cell tissue is assumed to have uniform and isotropic propagation, and constant electrical membrane properties. The stability of the numerical solution imposes the choice of a critical temporal step. A wave starts at a pacemaker cell; this electrical activity is initiated by the injection of an external stimulation current to the cell membrane. We observe synchronous wave propagation for axial resistance values around 0.5 GOmega or less and propoagation blocking for values greater than 0.7 GOmega. We compute the conduction velocity of the excitation, for different axial resistance values, and obtain a velocity about 10 cm/sec, approaching the one described by the literature for the rat at end of term.