É crescente a preocupação com as doenças do sono e o seu impacto na saúde da população em geral. Pouco ainda é conhecido e explorado na região Sul de Santa Catarina. Embora a literatura reforce a necessidade de uma avaliação objetiva, existem bons instrumentos clínicos que podem ser utilizados em estudos epidemiológicos. Foi realizado um estudo transversal e observacional com o objetivo de estimar a prevalência de sintomas relacionados a apneia obstrutiva do sono em um grupo de pacientes atendidos no Ambulatório de Clínicas Integradas da Universidade do Extremo Sul Catarinense, um ambulatório geral secundário, na cidade de Criciúma. Foram avaliados 101 pacientes através da aplicação de questões de sintomas de apneia validadas pelo estudo PLATINO e da Escala de Sonolência de Epworth. A amostra estudada tinha 73 (72,3%) mulheres; 47 (48,6%) indivíduos estudados tinham entre 40 e 59 anos. O ronco esteve presente em 65 (64,4%) pacientes e 20 (19,8%) relataram apneias. Dos indivíduos entrevistados, 31 (30,7%) relataram já terem sido questionados pelo seu médico a respeito do seu sono. Quanto ao resultado da ESE, 14 (13,9%) tiveram pontuação superior a 10. No sexo masculino, foi encontrada uma relação entre a presença de ronco e apneia e escores na ESE acima de 10 (p< 0,01). Concluímos que em uma população não selecionada o ronco foi um sintoma bastante prevalente, assim como o relato de apneias. As questões referentes ao sono, sobretudo relacionadas à apneia do sono, ainda são pouco abordadas pelos médicos em consultas gerais. / This observational cross-sectional study was conducted to determine the prevalence of symptoms related to obstructive sleep apnea in a group of patients attending Clínicas Integradas da Universidade do Extremo Sul Catarinense Ambulatory, a secondary ambulatory, in Criciuma, Brazil. Inclusion criteria was age 18 years or older. 101 patients were interviewed, and it were apllied questions related to obstructive apnea symptoms, previously validated in the PLATINO study and Epworth Sleepiness Scale. The sample was compounded by 73 (72,3%) women. 47 (48,6%) individuals were between 40 and 59 years old. Snores were present in 65 (64,4%) patients and 20 (19,8%) referred witnessed apneas during sleep. Thirty one (30,7%)of the participants said their physician have ever asked about sleep. The result on Epworth Sleepiness Scale was greater than 10 in 14 (13,9%) individuals. There was a significant relation between snore, witnessed apneas and Epworth Sleepiness Scale results greater than 10 in males (p<0,01). The prevalence of obstructive sleep apnea symptoms are high in this population, but Epworth Sleepiness Scale values are low. Besides, physicians still don’t ask much about sleep.

Το ροχαλητό είναι μία κοινή διαταραχή που επηρεάζει το 20-40% του συνολικού πληθυσμού. Ο μηχανισμός του ροχαλητού είναι στην ουσία η δόνηση ανατομικών δομών στον φαρυγγικό αεραγωγό. Η παλμική κίνηση της μαλθακής υπερώας ευθύνεται για τον δυνατό ήχο του ροχαλητού. Η αντικειμενική εκτίμηση του ροχαλητού είναι πολύ σημαντική, καθώς το ροχαλητό φέρει πληροφορία που σχετίζεται με τη θέση και το βαθμό της απόφραξης στο άνω αναπνευστικό σύστημα. Όπως η ομιλία, έτσι και το ροχαλητό παράγεται στη φωνητική κοιλότητα. Λόγω αυτής της αναλογίας, οι υπάρχουσες τεχνικές ανάλυσης της ομιλίας εφαρμόζονται στην εκτίμηση – αξιολόγηση του ροχαλητού. Οι τεχνικές ανίχνευσης-εκτίμησης περιλαμβάνουν στις περισσότερες των περιπτώσεων ολονύχτια εγγραφή των ήχων του ύπνου και ,στη συνέχεια, επεξεργασία αυτών των δεδομένων. Η ταξινόμηση γίνεται βάσει συγκεκριμένων κριτηρίων, όπως η ενέργεια, η φασματική κατανομή της ενέργειας ή άλλες παράμετροι που ορίζουν τα αντίστοιχα μαθηματικά μοντέλα που χρησιμοποιούνται. Στην εργασία αυτή, παρουσιάζουμε ένα διαφορετικό μηχανισμό ανίχνευσης του ροχαλητού. Με τις δυνατότητες που μας δίνει η χρήση ενσωματωμένων συστημάτων και μικροελεγκτών στην επεξεργασία σήματος, παρουσιάζουμε έναν τρόπο ανίχνευσης ροχαλητού με βάση την ενέργεια του σήματος. Για το σκοπό αυτό, χρησιμοποιούμε το περιβάλλον μVision της Keil, το οποίο μας παρέχει τη δυνατότητα εξομοίωσης του μικροελεγκτή ADuC7026, έχοντας στη διάθεσή μας μηδενικό Hardware. Έτσι, προγραμματίζουμε το μικροελεγκτή σε γλώσσα C για το πώς θα επεξεργάζεται τα αναλογικά σήματα εισόδου. Στη συνέχεια, ασχολούμαστε με πραγματικό υλικό, δηλαδή με την αναπτυξιακή πλακέτα της Olimex, η οποία έχει ενσωματωμένο και το μικροελεγκτή μας, λαμβάνοντας έτσι πραγματικά πλέον δεδομένα. / Snoring is a prevalent disorder affecting 20-40% of the general population. The mechanism of snoring is vibration of anatomical structure in the pharyngeal airway. Flutter of the soft palate accounts for the harsh aspect of the snoring sound. Objective assessment of snoring is very important, as snoring carries information relating to the site and the degree of obstruction of the upper airway. Similarly to speech, snoring is produced in the vocal tract. Because of this analogy, existing techniques for speech analysis have been applied to evaluate snoring sounds. The techniques of snoring detection and assessment use all night recording of sleep sounds, and processing of the extracted data. The classification is being conducted with specific criteria, such as energy or spectral energy distribution or other features that depend on the used mathematical method. In this thesis, we present a different mechanism of snoring detection. With the beneficial use of embedded systems and microcontrollers for signal processing, we present a method of snoring detection based on the signal energy. For this purpose, we use the uVision compiler, which provides full simulation of the microcontroller without any hardware. Therefore, we build a program in C language for the microcontroller to process the input analog signals. Subsequently, we load the program to the development board of Olimex, where has embedded the microcontroller we are interested to, and finally we receive real-time data.

É crescente a preocupação com as doenças do sono e o seu impacto na saúde da população em geral. Pouco ainda é conhecido e explorado na região Sul de Santa Catarina. Embora a literatura reforce a necessidade de uma avaliação objetiva, existem bons instrumentos clínicos que podem ser utilizados em estudos epidemiológicos. Foi realizado um estudo transversal e observacional com o objetivo de estimar a prevalência de sintomas relacionados a apneia obstrutiva do sono em um grupo de pacientes atendidos no Ambulatório de Clínicas Integradas da Universidade do Extremo Sul Catarinense, um ambulatório geral secundário, na cidade de Criciúma. Foram avaliados 101 pacientes através da aplicação de questões de sintomas de apneia validadas pelo estudo PLATINO e da Escala de Sonolência de Epworth. A amostra estudada tinha 73 (72,3%) mulheres; 47 (48,6%) indivíduos estudados tinham entre 40 e 59 anos. O ronco esteve presente em 65 (64,4%) pacientes e 20 (19,8%) relataram apneias. Dos indivíduos entrevistados, 31 (30,7%) relataram já terem sido questionados pelo seu médico a respeito do seu sono. Quanto ao resultado da ESE, 14 (13,9%) tiveram pontuação superior a 10. No sexo masculino, foi encontrada uma relação entre a presença de ronco e apneia e escores na ESE acima de 10 (p< 0,01). Concluímos que em uma população não selecionada o ronco foi um sintoma bastante prevalente, assim como o relato de apneias. As questões referentes ao sono, sobretudo relacionadas à apneia do sono, ainda são pouco abordadas pelos médicos em consultas gerais. / This observational cross-sectional study was conducted to determine the prevalence of symptoms related to obstructive sleep apnea in a group of patients attending Clínicas Integradas da Universidade do Extremo Sul Catarinense Ambulatory, a secondary ambulatory, in Criciuma, Brazil. Inclusion criteria was age 18 years or older. 101 patients were interviewed, and it were apllied questions related to obstructive apnea symptoms, previously validated in the PLATINO study and Epworth Sleepiness Scale. The sample was compounded by 73 (72,3%) women. 47 (48,6%) individuals were between 40 and 59 years old. Snores were present in 65 (64,4%) patients and 20 (19,8%) referred witnessed apneas during sleep. Thirty one (30,7%)of the participants said their physician have ever asked about sleep. The result on Epworth Sleepiness Scale was greater than 10 in 14 (13,9%) individuals. There was a significant relation between snore, witnessed apneas and Epworth Sleepiness Scale results greater than 10 in males (p<0,01). The prevalence of obstructive sleep apnea symptoms are high in this population, but Epworth Sleepiness Scale values are low. Besides, physicians still don’t ask much about sleep.

É crescente a preocupação com as doenças do sono e o seu impacto na saúde da população em geral. Pouco ainda é conhecido e explorado na região Sul de Santa Catarina. Embora a literatura reforce a necessidade de uma avaliação objetiva, existem bons instrumentos clínicos que podem ser utilizados em estudos epidemiológicos. Foi realizado um estudo transversal e observacional com o objetivo de estimar a prevalência de sintomas relacionados a apneia obstrutiva do sono em um grupo de pacientes atendidos no Ambulatório de Clínicas Integradas da Universidade do Extremo Sul Catarinense, um ambulatório geral secundário, na cidade de Criciúma. Foram avaliados 101 pacientes através da aplicação de questões de sintomas de apneia validadas pelo estudo PLATINO e da Escala de Sonolência de Epworth. A amostra estudada tinha 73 (72,3%) mulheres; 47 (48,6%) indivíduos estudados tinham entre 40 e 59 anos. O ronco esteve presente em 65 (64,4%) pacientes e 20 (19,8%) relataram apneias. Dos indivíduos entrevistados, 31 (30,7%) relataram já terem sido questionados pelo seu médico a respeito do seu sono. Quanto ao resultado da ESE, 14 (13,9%) tiveram pontuação superior a 10. No sexo masculino, foi encontrada uma relação entre a presença de ronco e apneia e escores na ESE acima de 10 (p< 0,01). Concluímos que em uma população não selecionada o ronco foi um sintoma bastante prevalente, assim como o relato de apneias. As questões referentes ao sono, sobretudo relacionadas à apneia do sono, ainda são pouco abordadas pelos médicos em consultas gerais. / This observational cross-sectional study was conducted to determine the prevalence of symptoms related to obstructive sleep apnea in a group of patients attending Clínicas Integradas da Universidade do Extremo Sul Catarinense Ambulatory, a secondary ambulatory, in Criciuma, Brazil. Inclusion criteria was age 18 years or older. 101 patients were interviewed, and it were apllied questions related to obstructive apnea symptoms, previously validated in the PLATINO study and Epworth Sleepiness Scale. The sample was compounded by 73 (72,3%) women. 47 (48,6%) individuals were between 40 and 59 years old. Snores were present in 65 (64,4%) patients and 20 (19,8%) referred witnessed apneas during sleep. Thirty one (30,7%)of the participants said their physician have ever asked about sleep. The result on Epworth Sleepiness Scale was greater than 10 in 14 (13,9%) individuals. There was a significant relation between snore, witnessed apneas and Epworth Sleepiness Scale results greater than 10 in males (p<0,01). The prevalence of obstructive sleep apnea symptoms are high in this population, but Epworth Sleepiness Scale values are low. Besides, physicians still don’t ask much about sleep.

Entre os distúrbios do sono relatados pela Academia Americana do Sono, o mais comum é a Síndrome da Apnéia e Hipopnéia Obstrutiva do Sono (SAHOS) que ocorre em razão da dificuldade da passagem ou interrupção total do fluxo do ar nas vias aéreas, provocando freqüentes despertares durante o sono, levando à sonolência diurna excessiva e interfere na saúde e na qualidade de vida dos indivíduos. A apnéia obstrutiva do sono gera conseqüências como: o ronco crônico, hipertensão sistêmica, sonolência excessiva, diminuição da libido, fadiga, depressão, aumento do risco para acidentes de trabalho e automobilísticos. Uma placa oral de avanço mandibular foi objeto deste estudo por propiciar um tratamento não invasivo, simples e bem aceito pelos pacientes. Nesta pesquisa foram avaliados 15 pacientes com apnéia do sono sem disfunções craniomandibulares (DCM), que apresentaram sonolência excessiva ou ronco. Os dados foram levantados mediante: polissonografia, antes e após instalação da placa oral; análise dos sinais e sintomas de DCM, por meio de questionário anamnético e pela palpação muscular e da ATM, e radiografias de teleperfil para verificar possíveis modificações na morfologia das vias aéreas superiores. A média do índice de apnéia e hipopnéia (IAH) antes do tratamento foi de 18,3 e, depois, de 4,1 (redução altamente significativa, p=0,001). Ocorreu um aumento significativo na menor saturação da oxihemoglobina (p=0,05), com diminuição significativa na sua dessaturação (p=0,05). Também ocorreu uma diminuição significativa nos microdespertares do sono (p=0,05). Para 14 pacientes com IAH<30, a taxa de redução no IAH foi de 75,9% e para 15 pacientes, incluindo um com IAH severo, a taxa de redução do IAH foi de 77,6%. Verificou-se também que o IAH reduziu abaixo de 10 em 13 pacientes (86,7%) e diminuiu acima de 50% em 14 pacientes (93,3%). Ocorreu melhora altamente significativa na sonolência diurna (p=0,005) em 87% dos pacientes. O tratamento provocou alterações dimensionais nas vias aéreas superiores e não foi observado desenvolvimento de DCM durante o período de acompanhamento. A placa desenvolvida neste estudo foi considerada efetiva para tratamento da SAHOS de graus leve a moderado. / Sleep-disorder breathing including obstructive sleep apnea hypopnea syndrome (OSAHS) and snoring is common and is believed to increase risk for morbidity and mortality. This disease occurs when abnormal breathing patterns like cessation of airflow disrupt sleep. Important clinical consequences of sleep apnea are cronic snoring, systemic hypertension, excessive sleepiness, depression and fatigue, sexual impairment and risk increased motor vehicle crashes and work-related accidents. Mandibulars repositioning appliances have been recommended for treatment of this disease because it is a non invasive treatment and well accepted by the patients. This study included 15 patients without temporomandibular disorders (TMD) and with excessive daytime sleepness or snoring. To get the datas the patients did two polysomnography and two cepholometrics radiographs, before and after treatment to examine upper airway dimensions and to access changes on TMD signs and symptons they answered anamnetic questionary for TMD and temporomandibular joints and muscle’s physical palpation were achieved. The IAH was reduced by the appliance intervention from 18,3 to 4,1 (p=0,001), and was reduced to below 10 in 13 patients (86,7%) and up to 50% in 14 patients (93,3%). The minor oxihemoglobin saturation increased significantly (p=0,05) and decreased on their dessaturation (p=0,05).The patients’ arouses decreased significantly(p=0,05). The IAH decreased rate was 75,9% in fourteen patients with IAH<30 and for fifteen patients with one severe IAH, the rate was 77,6%.The excessive daytime sleepiness improved significantly (p=0,005) in 87% patients.The treatment increased upper airway dimension and had no severe effect on the masticatory system and temporomandibular joints. In conclusion, this appliance showed to be effective for middle and moderate obstructive sleep apnea.

Entre os distúrbios do sono relatados pela Academia Americana do Sono, o mais comum é a Síndrome da Apnéia e Hipopnéia Obstrutiva do Sono (SAHOS) que ocorre em razão da dificuldade da passagem ou interrupção total do fluxo do ar nas vias aéreas, provocando freqüentes despertares durante o sono, levando à sonolência diurna excessiva e interfere na saúde e na qualidade de vida dos indivíduos. A apnéia obstrutiva do sono gera conseqüências como: o ronco crônico, hipertensão sistêmica, sonolência excessiva, diminuição da libido, fadiga, depressão, aumento do risco para acidentes de trabalho e automobilísticos. Uma placa oral de avanço mandibular foi objeto deste estudo por propiciar um tratamento não invasivo, simples e bem aceito pelos pacientes. Nesta pesquisa foram avaliados 15 pacientes com apnéia do sono sem disfunções craniomandibulares (DCM), que apresentaram sonolência excessiva ou ronco. Os dados foram levantados mediante: polissonografia, antes e após instalação da placa oral; análise dos sinais e sintomas de DCM, por meio de questionário anamnético e pela palpação muscular e da ATM, e radiografias de teleperfil para verificar possíveis modificações na morfologia das vias aéreas superiores. A média do índice de apnéia e hipopnéia (IAH) antes do tratamento foi de 18,3 e, depois, de 4,1 (redução altamente significativa, p=0,001). Ocorreu um aumento significativo na menor saturação da oxihemoglobina (p=0,05), com diminuição significativa na sua dessaturação (p=0,05). Também ocorreu uma diminuição significativa nos microdespertares do sono (p=0,05). Para 14 pacientes com IAH<30, a taxa de redução no IAH foi de 75,9% e para 15 pacientes, incluindo um com IAH severo, a taxa de redução do IAH foi de 77,6%. Verificou-se também que o IAH reduziu abaixo de 10 em 13 pacientes (86,7%) e diminuiu acima de 50% em 14 pacientes (93,3%). Ocorreu melhora altamente significativa na sonolência diurna (p=0,005) em 87% dos pacientes. O tratamento provocou alterações dimensionais nas vias aéreas superiores e não foi observado desenvolvimento de DCM durante o período de acompanhamento. A placa desenvolvida neste estudo foi considerada efetiva para tratamento da SAHOS de graus leve a moderado. / Sleep-disorder breathing including obstructive sleep apnea hypopnea syndrome (OSAHS) and snoring is common and is believed to increase risk for morbidity and mortality. This disease occurs when abnormal breathing patterns like cessation of airflow disrupt sleep. Important clinical consequences of sleep apnea are cronic snoring, systemic hypertension, excessive sleepiness, depression and fatigue, sexual impairment and risk increased motor vehicle crashes and work-related accidents. Mandibulars repositioning appliances have been recommended for treatment of this disease because it is a non invasive treatment and well accepted by the patients. This study included 15 patients without temporomandibular disorders (TMD) and with excessive daytime sleepness or snoring. To get the datas the patients did two polysomnography and two cepholometrics radiographs, before and after treatment to examine upper airway dimensions and to access changes on TMD signs and symptons they answered anamnetic questionary for TMD and temporomandibular joints and muscle’s physical palpation were achieved. The IAH was reduced by the appliance intervention from 18,3 to 4,1 (p=0,001), and was reduced to below 10 in 13 patients (86,7%) and up to 50% in 14 patients (93,3%). The minor oxihemoglobin saturation increased significantly (p=0,05) and decreased on their dessaturation (p=0,05).The patients’ arouses decreased significantly(p=0,05). The IAH decreased rate was 75,9% in fourteen patients with IAH<30 and for fifteen patients with one severe IAH, the rate was 77,6%.The excessive daytime sleepiness improved significantly (p=0,005) in 87% patients.The treatment increased upper airway dimension and had no severe effect on the masticatory system and temporomandibular joints. In conclusion, this appliance showed to be effective for middle and moderate obstructive sleep apnea.

Tracheal respiratory sounds analysis has been investigated as a non-invasive method to estimate respiratory flow and upper airway obstruction. However, the flow-sound relationship is highly variable among subjects which makes it challenging to estimate flow in general applications. Therefore, a robust model for acoustical flow estimation in a large group of individuals did not exist before. On the other hand, a major application of acoustical flow estimation is to detect flow limitations in patients with obstructive sleep apnea (OSA) during sleep. However, previously the flow--sound relationship was only investigated during wakefulness among healthy individuals. Therefore, it was necessary to examine the flow-sound relationship during sleep in OSA patients. This thesis takes the above challenges and offers innovative solutions. First, a modified linear flow-sound model was proposed to estimate respiratory flow from tracheal sounds. To remove the individual based calibration process, the statistical correlation between the model parameters and anthropometric features of 93 healthy volunteers was investigated. The results show that gender, height and smoking are the most significant factors that affect the model parameters. Hence, a general acoustical flow estimation model was proposed for people with similar height and gender. Second, flow-sound relationship during sleep and wakefulness was studied among 13 OSA patients. The results show that during sleep and wakefulness, flow-sound relationship follows a power law, but with different parameters. Therefore, for acoustical flow estimation during sleep, the model parameters should be extracted from sleep data to have small errors. The results confirm reliability of the acoustical flow estimation for investigating flow variations during both sleep and wakefulness. Finally, a new method for sleep apnea detection and monitoring was developed, which only requires recording the tracheal sounds and the blood's oxygen saturation level (SaO2) data. It automatically classifies the sound segments into breath, snore and noise. A weighted average of features extracted from sound segments and SaO2 signal was used to detect apnea and hypopnea events. The performance of the proposed approach was evaluated on the data of 66 patients. The results show high correlation (0.96,p < 0.0001) between the outcomes of our system and those of the polysomnography. Also, sensitivity and specificity of the proposed method in differentiating simple snorers from OSA patients were found to be more than 91%. These results are superior or comparable with the existing commercialized sleep apnea portable monitors.

Tracheal respiratory sounds analysis has been investigated as a non-invasive method to estimate respiratory flow and upper airway obstruction. However, the flow-sound relationship is highly variable among subjects which makes it challenging to estimate flow in general applications. Therefore, a robust model for acoustical flow estimation in a large group of individuals did not exist before. On the other hand, a major application of acoustical flow estimation is to detect flow limitations in patients with obstructive sleep apnea (OSA) during sleep. However, previously the flow--sound relationship was only investigated during wakefulness among healthy individuals. Therefore, it was necessary to examine the flow-sound relationship during sleep in OSA patients. This thesis takes the above challenges and offers innovative solutions. First, a modified linear flow-sound model was proposed to estimate respiratory flow from tracheal sounds. To remove the individual based calibration process, the statistical correlation between the model parameters and anthropometric features of 93 healthy volunteers was investigated. The results show that gender, height and smoking are the most significant factors that affect the model parameters. Hence, a general acoustical flow estimation model was proposed for people with similar height and gender. Second, flow-sound relationship during sleep and wakefulness was studied among 13 OSA patients. The results show that during sleep and wakefulness, flow-sound relationship follows a power law, but with different parameters. Therefore, for acoustical flow estimation during sleep, the model parameters should be extracted from sleep data to have small errors. The results confirm reliability of the acoustical flow estimation for investigating flow variations during both sleep and wakefulness. Finally, a new method for sleep apnea detection and monitoring was developed, which only requires recording the tracheal sounds and the blood's oxygen saturation level (SaO2) data. It automatically classifies the sound segments into breath, snore and noise. A weighted average of features extracted from sound segments and SaO2 signal was used to detect apnea and hypopnea events. The performance of the proposed approach was evaluated on the data of 66 patients. The results show high correlation (0.96,p < 0.0001) between the outcomes of our system and those of the polysomnography. Also, sensitivity and specificity of the proposed method in differentiating simple snorers from OSA patients were found to be more than 91%. These results are superior or comparable with the existing commercialized sleep apnea portable monitors.

Obstructive sleep apnoea hypopnoea syndrome (OSAHS) is a highly prevalent disease in which upper airways are collapsed during sleep, leading to serious consequences. The reference standard of clinical diagnosis, called Polysomnography (PSG), requires a full-night hospital stay connected to over 15 measuring channels requiring physical contact with sensors. The vast quantity of physiological data acquired during the PSG has to be manually scored by a qualified technologist to assess the presence or absence of the decease. The PSG is inconvenient, time consuming, expensive and unsuited for community screening. The limited PSG facilities around the world have resulted in long waiting lists and a large fraction of patients remain undiagnosed at present. There has been a flurry of recent activities in developing a portable technology to resolve this need. All the devices have at least one sensor that requires physical contact with the subject. Unattended systems have not led to sufficiently high sensitivity/specificity levels to be used in a routine home monitoring or a community screening exercise. OSAHS is a sleep respiratory disorder principally caused by functional deficiencies occurring in the upper airways during sleep. These conditions and the reduced muscle tone during sleep, cause the muscles in the upper airways to collapse partially or completely thus resulting in episodes of hypopnoea and apnoea respectively. During the process leading to collapse of upper airways, upper airways act as an acoustic filter frequently producing snoring sounds. The process of snore sound production leads us to hypothesise that snore sounds should contain information on changes occurring in the upper airways during the OSAHS. Snoring almost always accompanies the OSAHS and is universally recognised as its earliest symptom. At present, however, the quantitative analysis of snore sounds is not a practice in clinical OSAHS detection. The vast potential of snoring in the diagnosis/screening of the OSAHS remains unused. Snoring-based technology opens up opportunities for building community-screening devices that do not depend on contact instrumentation. In this thesis, we present our work towards developing a snore–based non-contact instrumentation for the diagnosis/screening of the OSAHS. The primary task in the analysis of Snore Related Sounds (SRS) would be to segment the SRS data as accurately as possible into three main classes, snoring (voiced non-silence), breathing (unvoiced non-silence) and silence. A new algorithm was developed, based on pattern recognition for the SRS segmentation. Four features derived from the SRS were considered to classify samples of the SRS into three classes. We also investigated the performance of the algorithm with three commonly-used noise reduction (NR) techniques in speech processing, Amplitude Spectral Subtraction (ASS), Power Spectral Subtraction (PSS) and Short Time Spectral Amplitude (STSA) Estimation. It was found that the noise reduction, together with a proper choice of features, could improve the classification accuracy to 96.78%. A novel model for the SRS was proposed for the response of a mixed-phase system (total airways response, TAR) to a source excitation at the input. The TAR/source model is similar to the vocal tract/source model in speech synthesis and is capable of capturing the acoustical changes brought about by the collapsing upper airways in the OSAHS. An algorithm was developed, based on the higher-order-spectra (HOS) to jointly estimate the source and the TAR, preserving the true phase characteristics of the latter. Working on a clinical database of signals, we show that the TAR is indeed a mixed phased signal and second-order statistics cannot fully characterise it. Nocturnal speech sounds can corrupt snore recordings and pose a challenge to the snore-based OSAHS diagnosis. The TAR could be shown to detect speech segments embedded in snores and derive features to diagnose the OSAHS. Finally presented is a novel technique for diagnosing the OSAHS, based solely on multi-parametric snore sound analysis. The method comprises a logistic regression model fed with a range of snore parameters derived from its features — the pitch and Total Airways Response (TAR) estimated using a Higher Order Statistics (HOS) based algorithm. The model was developed and its performance validated on a clinical database consisting of overnight snoring sounds simultaneously recorded during a hospital PSG using a high fidelity sound recording setup. The K-fold cross validation technique was used for validating the model. The validation process achieved an 89.3% sensitivity with 92.3% specificity (the area under the Receiver Operating Characteristic (ROC) curve was 0.96) in classifying the data sets into the two groups, the OSAHS (AHI >10) and the non-OSAHS. These results are superior to the existing results and unequivocally illustrate the feasibility of developing a snore-based non-contact OSAHS screening device.

Obstructive sleep apnoea hypopnoea syndrome (OSAHS) is a highly prevalent disease in which upper airways are collapsed during sleep, leading to serious consequences. The reference standard of clinical diagnosis, called Polysomnography (PSG), requires a full-night hospital stay connected to over 15 measuring channels requiring physical contact with sensors. The vast quantity of physiological data acquired during the PSG has to be manually scored by a qualified technologist to assess the presence or absence of the decease. The PSG is inconvenient, time consuming, expensive and unsuited for community screening. The limited PSG facilities around the world have resulted in long waiting lists and a large fraction of patients remain undiagnosed at present. There has been a flurry of recent activities in developing a portable technology to resolve this need. All the devices have at least one sensor that requires physical contact with the subject. Unattended systems have not led to sufficiently high sensitivity/specificity levels to be used in a routine home monitoring or a community screening exercise. OSAHS is a sleep respiratory disorder principally caused by functional deficiencies occurring in the upper airways during sleep. These conditions and the reduced muscle tone during sleep, cause the muscles in the upper airways to collapse partially or completely thus resulting in episodes of hypopnoea and apnoea respectively. During the process leading to collapse of upper airways, upper airways act as an acoustic filter frequently producing snoring sounds. The process of snore sound production leads us to hypothesise that snore sounds should contain information on changes occurring in the upper airways during the OSAHS. Snoring almost always accompanies the OSAHS and is universally recognised as its earliest symptom. At present, however, the quantitative analysis of snore sounds is not a practice in clinical OSAHS detection. The vast potential of snoring in the diagnosis/screening of the OSAHS remains unused. Snoring-based technology opens up opportunities for building community-screening devices that do not depend on contact instrumentation. In this thesis, we present our work towards developing a snore–based non-contact instrumentation for the diagnosis/screening of the OSAHS. The primary task in the analysis of Snore Related Sounds (SRS) would be to segment the SRS data as accurately as possible into three main classes, snoring (voiced non-silence), breathing (unvoiced non-silence) and silence. A new algorithm was developed, based on pattern recognition for the SRS segmentation. Four features derived from the SRS were considered to classify samples of the SRS into three classes. We also investigated the performance of the algorithm with three commonly-used noise reduction (NR) techniques in speech processing, Amplitude Spectral Subtraction (ASS), Power Spectral Subtraction (PSS) and Short Time Spectral Amplitude (STSA) Estimation. It was found that the noise reduction, together with a proper choice of features, could improve the classification accuracy to 96.78%. A novel model for the SRS was proposed for the response of a mixed-phase system (total airways response, TAR) to a source excitation at the input. The TAR/source model is similar to the vocal tract/source model in speech synthesis and is capable of capturing the acoustical changes brought about by the collapsing upper airways in the OSAHS. An algorithm was developed, based on the higher-order-spectra (HOS) to jointly estimate the source and the TAR, preserving the true phase characteristics of the latter. Working on a clinical database of signals, we show that the TAR is indeed a mixed phased signal and second-order statistics cannot fully characterise it. Nocturnal speech sounds can corrupt snore recordings and pose a challenge to the snore-based OSAHS diagnosis. The TAR could be shown to detect speech segments embedded in snores and derive features to diagnose the OSAHS. Finally presented is a novel technique for diagnosing the OSAHS, based solely on multi-parametric snore sound analysis. The method comprises a logistic regression model fed with a range of snore parameters derived from its features — the pitch and Total Airways Response (TAR) estimated using a Higher Order Statistics (HOS) based algorithm. The model was developed and its performance validated on a clinical database consisting of overnight snoring sounds simultaneously recorded during a hospital PSG using a high fidelity sound recording setup. The K-fold cross validation technique was used for validating the model. The validation process achieved an 89.3% sensitivity with 92.3% specificity (the area under the Receiver Operating Characteristic (ROC) curve was 0.96) in classifying the data sets into the two groups, the OSAHS (AHI >10) and the non-OSAHS. These results are superior to the existing results and unequivocally illustrate the feasibility of developing a snore-based non-contact OSAHS screening device.