Feature Selection for the Detection of Sleep Apnea using Multi-Bio Signals from Overnight Polysomnography

© 2018 IEEE. Patients with sleep apnea (SA) are at increased risk of stroke and cardiovascular disease. Diagnosis of sleep apnea depends on the standard overnight polysomnography (PSG). In this study, the DREAM Apnea Database was used to evaluate the importance of the various features proposed in the literature for the analysis of sleep apnea. Various timeand frequency- domain features that include wavelet and power spectral density were extracted from ECG, EMG, EEG, airflow, SaO2, abdominal and thoracic recordings. Evaluation measures of one-way analysis of variance (ANOVA) and Rank-Sum test were used to test the performance of different features. The selected feature subset indicated that frequency-domain features outperform time-domain ones. This study will help in enhancing the detection accuracy of sleep apnea for the various polysomnography signals

Huomaamattomat mittausmenetelmät unen laadun tarkkailussa

Sleep is an important part of health and well-being. While sleep quantity is directly measurable, sleep quality has traditionally been assessed with subjective methods such as questionnaires. The study of sleep disorders has for a long time been confined to clinical environments, and patients have had to endure cumbersome procedures involving multiple electrodes placed on the body. Recent developments in sensor technology as well as data analysis methods have enabled continuous, unobtrusive sleep data recording in the home environment. This has opened new possibilities for studying various sleep parameters and their effect on the quality of sleep. This thesis consists of two parts. The first part is a literature review examining the field of sleep quality research with focus on the application of intelligent methods and signal processing. The second part is a descriptive data analysis look at sleep data obtained with non-invasive sensors.Uni on terveyden ja hyvinvoinnin keskeinen tekijä. Unen määrä on helposti mitattavissa, mutta unen laatua on perinteisesti seurattu kyselylomakkeiden kaltaisin subjektiivisin menetelmin. Unihäiriöiden tutkiminen on pitkään rajoittunut kliinisiin ympäristöihin, ja potilaiden on täytynyt sietää hankalia tutkimusmenetelmiä useine kehoon kiinnitettävine elektrodeineen. Anturiteknologian ja data-analyysimenetelmien kehittyminen on mahdollistanut unidatan jatkuvan ja huomaamattoman tallentamisen kotiympäristössä. Tämä on avannut uusia mahdollisuuksia sekä unen ominaisuuksien että niiden unen laatuun vaikuttavien tekijöiden tutkimiselle. Tämä tutkimus jakautuu kahteen osaan. Ensimmäinen osa on kirjallisuuskatsaus unen laadun tutkimukseen, painopisteenä älykkäiden menetelmien ja signaalinkäsittelyn soveltaminen. Toisessa osassa esitellään huomaamattomilla sensoreilla kerättävän unidatan tutkimista ja sen deskriptiivistä data-analyysiä, esimerkkinä ballistokardiografia

Obesity and asthma: The role of innate immunity, adipokines and regulatory T cells.

Introduction: Obesity and asthma are associated but the mechanism is poorly understood. Enhanced systemic inflammation may underlie the obesity-asthma paradigm. Although there is good mechanistic data that obesity augments the immune response as well as promoting immune dysregulation by reducing regulatory T cell numbers, there is little work relating this to obesity and asthma. Methods: A case-control study examined 6 groups of pre-menopausal women (n=84); non-obese, f overweight and obese individuals with and without asthma. Measures of adiposity and lung function I were taken and peripheral blood collected during the first 7 days of the menstrual cycle. Innate immune parameters measured included: full blood count and differential; chemiluminescence recorded whole blood reactive oxygen species; neutrophil related cytokines; neutrophil and i monocyte activation markers by flow cytometry, and LPS induced whole blood cytokine responses. Insulin resistance, adipokine levels and free fatty acid levels were recorded. Dendritic cell and lymphocyte subtypes including FoxP33+ regulatory T cells (Tregs) were quantified by flow cytometry I and PHA-induced cytokine responses measured in whole blood. Results: Obesity and asthma appeared to have synergistic effects with regards to circulating I neutrophil count, plasma IL-6 and leptin with obese asthmatics having the highest levels. Reactive I oxygen species production followed a similar trend. Increasing BMI within asthmatics was associated f with a reduction in eosinophils and myeloid dendritic cells, and increased PHA-induced IFNy. Obesity I across the entire study group was associated with increased neutrophil counts and neutrophil P related cytokines, reduced FoxPS3+Tregs and increased PHA-induced IL-17 response. Conclusions: Systemic changes in immunity occur in obesity and asthma; some of these are additive. Within asthmatics, obesity is associated with responses suggesting T helper 1 (Th1) rather than Th2 bias. Obesity-associated systemic changes in immunity might encourage a loss of immune tolerance. These findings suggest that obesity might mediate its effects in asthma through systemic inflammatory mechanisms

Detection of non-stationary dynamics using sub-space based representations, cyclic based and variability constraints

La siguiente Tesis de Maestría propone una metodología para el análisis de series de tiempo no-estacionarias con el propósito de filtrado y detección de ruido en reconocimiento de patrones. La metodología se encuentra dividida en dos etapas: el análisis de comportamientos no-estacionarios que recaen en procesos cíclicos y como diferentes componentes no-periódicos afectan el análisis de la señal. El segundo enfoque, está centrado en el problema de extracción de series de tiempo no-estacionarias que afectan procesos estacionarios. Ambos esquemas están basados en restricciones de (ciclo-)estacionariead y representaciones basadas en subespacios de manera que mediante la evaluación de las dinámicas de la señal sea posible identificar las componentes no-estacionarias indeseadas. Los resultados se muestran para cada enfoque de manera independiente por medio de datos sintéticos y reales, el desempeño obtenido muestra una gran capacidad de detección, rechazo y/o extracción de ruido y artefactos en series de tiempo (ciclo-)estacionarias usando restricciones de estacionariedad así como condiciones cíclicas basadas en la naturaleza de la señalAbstract : The present Master’s Thesis proposes a methodology for the non–stationary time-series analysis for filtering and noise rejection purposes in pattern recognition. The methodology is divided into two different approaches: the analysis of periodic non–stationary behavior that relies into a cyclic process and how additional non–cyclic non–stationarities disrupt and affect the signal processing. Second approach deals with the problem of non–stationary signal extraction that affects inherent weak stationary processes. Both frameworks of analysis take base on (cyclo-)stationary constraints and subspace based representations in order to assess and characterize the signals dynamics to facilitate the identification of the undesired non–stationary components. Results are shown over each approach with different real and synthetic data, the obtained performances show high rejection, detection and extraction capabilities for noise and artifacts in (cyclo)–stationary signals using external and internal based constraints of analysis and high separation capability for stationary signalsMaestrí

Type 1 ryanodine receptor interactions

Excitation-contraction coupling is an essential part of skeletal muscle contraction. It encompasses the sensing of depolarisation of the plasma membrane coupled with the release of Ca2+ from intracellular stores. The channel responsible for this release is called the Ryanodine receptor (RyR), and forms a hub of interacting proteins which work in concert to regulate the release of Ca2+ through this channel. The aim of this work was to characterise possible novel interactions with a proline-rich region of the RyR1, to characterise a monoclonal antibody (mAb VF1c) raised against a junctional sarcoplasmic reticulum protein postulated to interact with RyR1, and to characterise the protein recognised by this antibody in models of skeletal muscle disease such as Duchenne Muscular dystrophy (DMD) and sarcopenia. These experiments were performed using cell culture, protein purification via immunoprecipitation, affinity purification, low pressure chromatography and western blotting techniques. It was found that the RyR1 complex isolated from rat skeletal muscle co-purifies with the Growth factor receptor bound protein 2 (GRB2), very possibly via an interaction between the proline rich region of RyR1 and one of the SH3 domains located on the GRB2 protein. It was also found that Pleiotrophin and Phospholipase Cγ1, suggested interactors of the proline rich region of RyR1, did not co-purify with the RyR1 complex. Characterisation of mAb VF1c determined that this monoclonal antibody interacts with junctophilin 1, and binds to this protein between the region of 369-460, as determined by western blotting of JPH1 fragments expressed in yeast. It was also found that JPH1 and JPH2 are differentially regulated in different muscles of rabbit, where the highest amount of both proteins was found in the extensor digitorum longus (EDL) muscle. JPH1 and 2 levels were also examined in three rodent models of disease: the mdx mouse (a model of DMD), chronic intermittent hypoxia (CIH)-treated rat, and aged and adult mice, a model of sarcopenia. In the EDL and soleus muscle of CIH treated rats, no difference in either JPH1 or JPH2 abundance was detected in either muscle. An examination of JPH1 and 2 expression in mdx and wild type controls diaphragm, vastus lateralis, soleus and gastrocnemius muscle found no major differences in JPH1 abundance, while JPH2 was decreased in mdx gastrocnemius compared to wild type. In a mouse model of sarcopenia, JPH1 abundance was found to be increased in aged soleus but not in aged quadriceps, while in exercised quadriceps, JPH2 abundance was decreased compared to unexercised controls. Taken together, these results have implications for the regulation of RyR1 and JPH1 and 2 in skeletal muscle in both physiological and pathological states, and provide a newly characterised antibody to expand the field of JPH1 research

IX Malta Medical School Conference

Abstracts of papers presented at the 9th Malta Medical School Conference held at the Hilton Malta Hotel, Portomaso, St. Julians between 3rd and 5th December 2015.peer-reviewe