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Bakgrund: Obstruktivt sömnapnésyndrom (OSA) kan påverkas positivt av fysioterapeutiska interventioner. Det är därför intressant att veta hur initial motivation och self-efficacy påverkar livsstilsförändring i form av fysisk aktivitetsnivå och fysisk kapacitet. Syfte: Undersöka hur initial motivation och self-efficacy förändrar fysisk aktivitetsnivå, och hur initial self-efficacy förändrar fysisk kapacitet, hos personer med OSA. Metod: Kvantitativ dataanalys med data från en tidigare RCT där personer med OSA fick Behavioral Sleep Medicine. Motivation (vid baslinje) och self-efficacy (vid baslinje) korrelerades med förändringen av fysisk aktivitetsnivå (från baslinje till 6 månader), och motivation (vid baslinje) korrelerades med förändringen av fysisk kapacitet (från baslinje till 6 månader). Kontroll- och interventionsgruppen jämfördes även i skillnad på aktivitetsnivå mellan baslinje och 6 månader. Resultat: Inga statistiskt signifikanta samband kunde påvisas mellan motivation och förändring av fysisk aktivitetsnivå (p = 0.439 och 0.615 för kontroll- respektive interventionsgruppen), motivation och förändring av fysisk kapacitet (p = 0.538 och 0.375 för kontroll- respektive interventionsgruppen), self-efficacy och förändring av fysisk aktivitetsnivå (p = 0.392 och 0.925 för kontroll- respektive interventionsgruppen), eller skillnad i förändring av aktivitetsnivå mellan kontroll- respektive interventionsgrupp (p = 0.545). Konklusion: Ingen tydlig koppling mellan initial motivation och self-efficacy till förändring av fysisk aktivitetsnivå och fysisk kapacitet kunde påvisas hos personer med OSA. / Background: Obstructive sleep apnea (OSA) can be positively affected by physiotherapeutic interventions. It is therefore interesting to know how motivation and self-efficacy affects lifestyle changes in the form of physical activity level and physical capacity. Purpose: To analyze how initial motivation and self-efficacy changes physical activity levels, and how initial motivation changes physical capacity, in people with OSA. Method: Quantitative data analysis using data from a previous RCT in which people with OSA were treated with Behavioral Sleep Medicine. Motivation (at baseline) and self-efficacy (at baseline) was correlated with the change in physical activity levels (from baseline to 6 months), and motivation (at baseline) was correlated with the change in physical capacity (from baseline to 6 months). The difference in the change in activity levels from baseline to 6 months was also compared between the control and intervention groups. Results: No statistically significant correlations were found between motivation and physical activity level (p = 0.439 and 0.615 for the control and intervention group respectively), motivation and physical capacity (p = 0.538 and 0.375 for the control and intervention group respectively), self-efficacy and change of physical activity level (p = 0.392 and 0.925 for the control and intervention group respectively), or difference in the control versus intervention group regarding change in physical activity level (p = 0.545). Conclusion: No clear connection between initial motivation and self-efficacy to change in physical activity levels and physical capacity could be found in people with OSA.

The purpose of the current study was to test the hypothesis that chronic hypoxia associated with sleep-disordered breathing relates to abnormal Nitric Oxide (NO) production and vascular endothelial growth factor (VEGF) expression patterns that contribute to aberrancy of specific determinates of cardiovascular and cardiopulmonary function before, during, and after graded exercise. These patterns may further reflect pathologic alteration of signaling within the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt-1) transduction network. To this end, 7 medically diagnosed OSA patients (3 male, 4 female), mean age 48 years and 7 apparently healthy control subjects (3 male, 4 female), mean age 42 years, underwent baseline venous blood draws and maximal bicycle ergometry. Mononuclear cells isolated from peripheral blood were utilized as reporter cells for measurement of VEGF, Akt-1, hypoxia inducible factor-1 alpha (HIF-1 alpha), and vascular endothelial growth factor receptor-2 (VEGFR2) gene expression by redundant oligonucleotide DNA microarray and real-time PCR technologies. Circulating angiogenic progenitor cells expressing VEGFR2 were profiled by flow cytometry. Plasma and serum concentrations of VEGF, nitrates/nitrites, catecholamines, and dopamine were measured by enzyme-linked immunosorbent assay (ELISA) and high performance liquid chromatography (HPLC). Arterial blood pressure, cardiac output, oxygen consumption and total peripheral resistance were determined at Baseline, 100W, and peak ergometric stress by standard techniques. There were no apparent differences (p < .05) observed in biochemical markers relating to vascular function and adaptation including, serum nitrates/nitrites, norepinephrine, dopamine, and plasma VEGF. No differences were found relative to cardiac output, stroke volume, cardiopulmonary or myocardial oxygen consumption, expired ventilation, heart rate, arteriovenous oxygen difference, total peripheral resistance, and mean arterial pressure. Due to methodological issues related to the redundant oligonucleotide DNA microarray and real-time PCR gene expression analyses, results of these experiments were uninterpretable. Thus, the research hypothesis was rejected. Conversely, significant (p < .05) differences were observed in waist: hip ratios, recovery: peak systolic blood pressure ratio at 1 minute post-exercise and %VEGFR2 expression. OSA was associated with elevations in both waist: hip ratios and recovery: peak systolic blood pressure ratio at 1 minute post-exercise as well as significant depression of %VEGFR2 profiles. Moreover, significant negative correlations were found regarding waist: hip ratios and %VEGFR2 expression (r = -.69;p =.005) and recovery: peak systolic blood pressure ratio at 1 minute post-exercise and %VEGFR2 expression (r = -.65;p =.01). These findings did not provide evidence that NO-dependent vasoactive mechanisms are suppressed nor did they support the supposition that angiogenic mechanisms are pathologically activated in sleep-disordered breathing. / Ph. D.

Obstructive sleep apnea syndrome (OSAS), a chronic respiratory disorder affecting as many as 1 in 5 adults, is associated with repetitive collapse of the upper airway during sleep and results in fragmented sleep and intermittent periods of hypoxia and hypercapnia. If left untreated, OSAS increases the risk for hypertension, insulin resistance, metabolic syndrome (MetS) in a manner that is independent of obesity in mid-adulthood. However, it is still unknown if evidence of these relationships is apparent in young adults with OSAS who are otherwise healthy and free of other chronic comorbidities. Objectives: To determine if functional and biochemical evidence of insulin resistance, MetS, and vascular endothelial dysfunction (VED) exists in young, overweight men with OSAS and if the combined effects of obesity and OSAS augments the evidence of chronic disease pathogenesis beyond the effects of obesity alone. Subjects: Subjects were 12 overweight men with OSAS (age = 22.8 ± 0.8; BMI = 32.4 ± 1.0; apnea-hypopnea index (AHI) = 25.4 ± 5.4), 17 overweight men without OSAS (age = 22.5 ± 0.7; BMI = 31.6 ± 1.1; AHI = 2.2 ± 0.3), and 18 normal weight men without OSAS (age = 21.1 ± 0.5; BMI = 22.4 ± 0.4; AHI = 1.9 ± 0.3). Methods: Subjects were evaluated for OSAS using an unsupervised, portable polysomnography test. Total fat and central abdominal fat (CAF) were assessed using dual energy x-ray absorptiometry (DEXA). Fasting blood samples were used to quantify biochemical markers for insulin resistance (glucose, insulin, adiponectin, IL-6, and TNF-á) and endothelial dysfunction (CRP, VEGF, and VEGFR2) using ELISA, RIA, and flow cytometry. MetS was defined according to Adult Treatment Panel III (ATP III) clinical standards. Triglycerides, HDL cholesterol, and glucose were measured using a commercial lipid panel. Resting blood pressure was obtained manually via auscultation. VED was measured via strain gauge plethysmography, with endothelium-dependent vasodilatation being assessed from forearm reactive hyperemia after a 5-minute period of upper arm occlusion. Statistics: One-way ANOVA was used to determine group differences in variables. Two-way ANOVA was used to evaluate group x time interactions during the 2-minute recovery period following upper arm occlusion. Pearson partial correlation was used to assess relationships between continuous variables, with analyses being controlled for CAF or OSAS severity. Spearman correlation was used to assess relationships between number of MetS components present and both indices of adiposity and OSAS severity. Stepwise multiple linear regression analysis was used to determine significant predictors of OSAS severity, insulin resistance, components of the MetS, and endothelial dysfunction. Results: Overweight subjects with OSAS had more CAF, higher fasting triglycerides, and lower serum adiponectin concentrations than both overweight and normal weight non-apneic controls. Furthermore, fasting triglycerides were directly correlated to OSAS severity, even after the influence of central abdominal fat was removed. OSAS severity was an independent predictor of triglyceride levels, and vice versa. Insulin resistance, leptin, insulin, and CRP were all higher in overweight subjects than controls, but no further differences were attributable to severity of OSAS. No differences in IL-6, TNF-á, ADMA, and expression of VEGFR2 were noted between any groups. No group or group x time interaction differences existed in regards to postocclusive reactive hyperemia responses. Conclusions: Young men with OSAS exhibit several unique anthropometric and biochemical abnormalities that may indicate early pathogenesis of or increased risk for future development for cardiovascular and metabolic disorders. Identification and treatment of OSAS at this age may be critical to prevent the onset and progression of these chronic disorders. / Ph. D.

Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS) is a breathing disorder characterized by recurrent episodes of upper airway collapse during sleep. Measuring cardiac function in OSAHS patients may provide information to help delineate not only chronic effects of autonomic imbalance and ventricular loading in the diseases state, but also possible beneficial effects of clinical treatments. Objectives (Study 1): The aim of this study was to determine the reproducibility of select cardiac variables when monitoring a simulated sleep apnea event using a new improved bioimpedance cardiography system. Methods: Fifteen apparently healthy males were tested on three different days in a protocol requiring their performance of two 15 sec and two 30 sec forced and sustained inspiratory efforts against a closed epiglottis (Müeller Maneuver-MM). Results: Changes in cardiac output (CO), heart rate (HR), stroke volume (SV), myocardial contractility index (MCI) and systemic vascular resistance (SVR) were similar during 15 sec and 30 sec MM in all three days. During 30 sec MM, these changes in cardiac function were pronounced in comparison to the minimal variations observed for the 15 sec MM challenge test. Objectives (Study 2): The aim of this study was to characterize the cardiac responses to negative intrathoracic pressure in OSAHS patients with and without hypertension versus healthy subjects. Methods: Two groups of 10 OSAHS patients, one without HTN and one with HTN were compared with a control group. Each subject underwent two 30 sec (MM) as previously described. Results: During MM, there were similar changes in SV, HR and SVR in all three groups. CO was lower during MM in controls compared to OSAHS groups, whereas MCI decreased during MM in both controls and OSAHS+HTN groups (-7.5% and -1.7%, respectively) compared with an increase in OSAHS group (11.8%). During a Post-MM, both OSAHS groups showed return of cardiac responses toward their pre-MM baseline within 30 sec. Conclusions: The new bioimpedance cardiograph evaluated in this study was found to be reliable for measuring acute changes in cardiac responses to this breathing challenge test. OSAHS may cause acute changes in selected cardiac parameters during and immediately after a breathing challenge test. / Ph. D.

Obstructive sleep apnea (OSA) is common in older U.S. adults and the prevalence is anticipated to rise in this age group along with obesity, a prominent risk factor for OSA. Recently, OSA was determined to be highly prevalent among patients with abdominal aortic aneurysm (AAA) disease. Objectives: Examine associations between OSA risk and physical activity (PA), metabolic syndrome (MetSyn), and exercise responses to cardiopulmonary exercise testing (CPET) in elderly patients with AAA disease. Methods: Elderly patients (n=326 for Studies 1 and 2; n=114 for Study 3) newly diagnosed with small AAAs (aortic diameter "2.5 and < 5.5 cm) were recruited. Data collection for all participants included: extraction of medical history and drug information from medical records; completion of a physical examination to assess resting vital signs and anthropometrics; fasting blood draw for several biochemical analyses; completion of a cardiopulmonary exercise test (CPET); and completion of interviews and questionnaires for health history, PA, and OSA risk. Results: 57% of subjects were High-risk for OSA and 17% were classified in the highest-risk Berlin Risk Score (BRS) 3 group; these subjects reported fewer blocks walked/day, flights of stairs climbed/day, and expended fewer Calories when engaged in these activities compared to Low-risk counterparts, independent of obesity. Among those at High-risk for OSA, 45% had MetSyn. Subjects with the highest BRS also had the highest prevalence of MetSyn and values for the MetSyn component biomarkers. Exercise capacity and physiological responses at rest, during exercise, and recovery were similar between groups at High- and Low-risk for OSA. Conclusions: Reduced levels of PA among elderly AAA patients at High-risk for OSA could have unfavorable implications for cardiovascular disease (CVD) risk and all-cause and CVD mortality.  Subjects demonstrating the most clinical symptoms of OSA showed a significantly higher prevalence for MetSyn and several of the biomarkers that determine MetSyn. In clinical practice, the BRS may be useful for identifying those AAA patients at increased risk for both OSA and MetSyn. / Ph. D.

Introdução: A Apneia Obstrutiva do Sono (AOS) é uma doença crônica e evolutiva que tem uma alta prevalência e pode acarretar graves repercussões hemodinâmicas, neurológicas e comportamentais. A pressão positiva contínua na via aérea (CPAP) é altamente eficaz no tratamento da AOS, porém o processo de expansão da faringe por este dispositivo não é totalmente entendido. A faringometria acústica (FA) é um método de mensuração das dimensões da cavidade oral e da faringe, reprodutível e fácil de efetuar, podendo avaliar eficientemente os efeitos do CPAP na faringe e trazer informações sobre sua complacência e sítios de obstrução. Objetivo: avaliar as mudanças induzidas pelo CPAP nas dimensões da faringe e no posicionamento do palato mole em pacientes com AOS e verificar se a deformabilidade da via aérea superior pelo CPAP é maior em apneicos graves do que em roncadores simples. Desenho do estudo: estudo prospectivo. Métodos: 48 pacientes foram submetidos a FA durante o uso do CPAP. 29 pacientes com índice de apneia e hipopneia (IAH) >30 e indicação de uso do CPAP foram inclusos no grupo AOS, e 19 pacientes com IAH <=5 foram inclusos no grupo controle. Os critérios de inclusão foram: idade entre 18 e 65 anos, ambos os sexos, polissonografia (PSG) previamente realizada, e PSG para titulação do CPAP no grupo AOS. Os critérios de exclusão foram: obstrução nasal crônica pré existente, uso de medicamentos psiquiátricos, neurológicos ou miorrelaxantes, insuficiência cardíaca congestiva, índice de massa corpórea >= 35 e cirurgia palatal prévia para AOS. Os gráficos resultantes dos exames de FA foram analisados por 2 examinadores cegos que marcaram os pontos para obtenção da distância da transição orofaríngea da glote. Foram calculados também o comprimento e o volume da faringe pelo programa do aparelho. Foi então feita a análise estatística para comparar as medidas em diferentes pressões intragrupo e intergrupo. Resultados: As medidas dos dois examinadores mostraram correlação. O CPAP não ocasionou nenhum aumento significativo na via aérea faríngea nem mudou o posicionamento do palato em ambos os grupos. No estado basal, os pacientes com AOS têm uma faringe mais longa do que os roncadores simples. Após a aplicação do CPAP, não houve diferença no comprimento e no volume da faringe entre os grupos. Conclusões: Não houve diferenças significantes na posição da transição orofaríngea e da glote entre roncadores e apneicos com a aplicação de CPAP. Não houve expansão significante na via aérea faríngea com a aplicação de CPAP nos roncadores e apneicos. Anatomicamente, os apneicos apresentaram via aérea superior mais longa que os roncadores simples / Rationale: Obstructive Sleep Apnea (OSA) is an evolutive disease, with a high prevalence, that can cause serious hemodynamic, neurological and behavioral repercussions. Continuous positive airway pressure (CPAP) is highly effective in OSA treatment, however the pharynx expansion by this advice is not fully understood. Acoustic pharyngometry (AP) is a measurement method of oral cavity and pharynx dimensions, and can efficiently evaluate CPAP effects on pharynx, bringing informations about its compliance and sites of obstruction. Objectives/Hypothesis: To verify if the CPAP-induced deformability on the pharynx and soft palate is greater in obstructive sleep apnea (OSA) patients than in simple snorers. Study Design: Prospective study. Methods: 29 patients with severe OSA and 19 simple snorers underwent acoustic pharyngometry measurements while awake in supine position. Measurements were first made without CPAP, and then with a nasal CPAP starting with 4cmH2O and up to 10cmH2O. The oropharyngeal transition and the position of the glottis were marked in the generated curves by two blinded examiners. The marked values were averaged to calculate the oropharyngeal transition and the pharyngeal length and volume under zero, 4 and 10cmH2O of CPAP for each group. Results: CPAP did not produce any significant enlargement in the pharyngeal airway nor changed the soft palate positioning in both groups. At baseline, OSA patients have a longer pharynx than simple snorers. After the application of CPAP, there was no difference in the length and volume of the pharynx between groups. Conclusions: There were no significant differences in the position of oropharyngeal junction and glottis between snorers and apneics with CPAP appliance. There was no significant expansion in pharyngeal airway with CPAP appliance in snorers and apneics. Anatomically, apneics presented a longer superior airway than simple snorers

Introdução: A Apneia Obstrutiva do Sono (AOS) é uma doença crônica e evolutiva que tem uma alta prevalência e pode acarretar graves repercussões hemodinâmicas, neurológicas e comportamentais. A pressão positiva contínua na via aérea (CPAP) é altamente eficaz no tratamento da AOS, porém o processo de expansão da faringe por este dispositivo não é totalmente entendido. A faringometria acústica (FA) é um método de mensuração das dimensões da cavidade oral e da faringe, reprodutível e fácil de efetuar, podendo avaliar eficientemente os efeitos do CPAP na faringe e trazer informações sobre sua complacência e sítios de obstrução. Objetivo: avaliar as mudanças induzidas pelo CPAP nas dimensões da faringe e no posicionamento do palato mole em pacientes com AOS e verificar se a deformabilidade da via aérea superior pelo CPAP é maior em apneicos graves do que em roncadores simples. Desenho do estudo: estudo prospectivo. Métodos: 48 pacientes foram submetidos a FA durante o uso do CPAP. 29 pacientes com índice de apneia e hipopneia (IAH) >30 e indicação de uso do CPAP foram inclusos no grupo AOS, e 19 pacientes com IAH <=5 foram inclusos no grupo controle. Os critérios de inclusão foram: idade entre 18 e 65 anos, ambos os sexos, polissonografia (PSG) previamente realizada, e PSG para titulação do CPAP no grupo AOS. Os critérios de exclusão foram: obstrução nasal crônica pré existente, uso de medicamentos psiquiátricos, neurológicos ou miorrelaxantes, insuficiência cardíaca congestiva, índice de massa corpórea >= 35 e cirurgia palatal prévia para AOS. Os gráficos resultantes dos exames de FA foram analisados por 2 examinadores cegos que marcaram os pontos para obtenção da distância da transição orofaríngea da glote. Foram calculados também o comprimento e o volume da faringe pelo programa do aparelho. Foi então feita a análise estatística para comparar as medidas em diferentes pressões intragrupo e intergrupo. Resultados: As medidas dos dois examinadores mostraram correlação. O CPAP não ocasionou nenhum aumento significativo na via aérea faríngea nem mudou o posicionamento do palato em ambos os grupos. No estado basal, os pacientes com AOS têm uma faringe mais longa do que os roncadores simples. Após a aplicação do CPAP, não houve diferença no comprimento e no volume da faringe entre os grupos. Conclusões: Não houve diferenças significantes na posição da transição orofaríngea e da glote entre roncadores e apneicos com a aplicação de CPAP. Não houve expansão significante na via aérea faríngea com a aplicação de CPAP nos roncadores e apneicos. Anatomicamente, os apneicos apresentaram via aérea superior mais longa que os roncadores simples / Rationale: Obstructive Sleep Apnea (OSA) is an evolutive disease, with a high prevalence, that can cause serious hemodynamic, neurological and behavioral repercussions. Continuous positive airway pressure (CPAP) is highly effective in OSA treatment, however the pharynx expansion by this advice is not fully understood. Acoustic pharyngometry (AP) is a measurement method of oral cavity and pharynx dimensions, and can efficiently evaluate CPAP effects on pharynx, bringing informations about its compliance and sites of obstruction. Objectives/Hypothesis: To verify if the CPAP-induced deformability on the pharynx and soft palate is greater in obstructive sleep apnea (OSA) patients than in simple snorers. Study Design: Prospective study. Methods: 29 patients with severe OSA and 19 simple snorers underwent acoustic pharyngometry measurements while awake in supine position. Measurements were first made without CPAP, and then with a nasal CPAP starting with 4cmH2O and up to 10cmH2O. The oropharyngeal transition and the position of the glottis were marked in the generated curves by two blinded examiners. The marked values were averaged to calculate the oropharyngeal transition and the pharyngeal length and volume under zero, 4 and 10cmH2O of CPAP for each group. Results: CPAP did not produce any significant enlargement in the pharyngeal airway nor changed the soft palate positioning in both groups. At baseline, OSA patients have a longer pharynx than simple snorers. After the application of CPAP, there was no difference in the length and volume of the pharynx between groups. Conclusions: There were no significant differences in the position of oropharyngeal junction and glottis between snorers and apneics with CPAP appliance. There was no significant expansion in pharyngeal airway with CPAP appliance in snorers and apneics. Anatomically, apneics presented a longer superior airway than simple snorers

<p>Enthusiasm for uvulopalatopharyngoplasty (UPPP) in the treatment of mild-to-moderate obstructive sleep apnea syndrome (OSAS) has declined in recent years, partly because of a lower success rate over time and partly because of adverse effects. In more severe cases, the patients are generally treated with nasal continuous positive airway pressure (CPAP). However, many patients do not satisfactorily tolerate CPAP as a result of frequent side-effects. Consequently, there is a need for an alternative treatment. Reports on the beneficial effects of mandibular advancement appliances in the treatment of mild-to-moderate OSA exist in the form of short–term evaluations.</p><p>One of the aims of the present thesis was to compare treatment effects with a mandibular advancement appliance and UPPP in patients with OSA with follow-up after one and four years. Ninety-five male patients with confirmed mild-to-moderate OSA (apnea index, AI >5 and <25) were randomised to treatment with a dental appliance or UPPP. Sleep studies were performed before and one and four years after intervention. According to the criteria for normalisation (AI<5 and apnea hypopnea index, AHI<10), 78% of the patients in the dental appliance group and 51% of the patients in the UPPP group had normalised after one year (p<0.05). Still after four years of treatment, 63% of the patients in the dental appliance group and 33% of the patients in the UPPP group were normalised. The dental appliance group had a higher normalisation rate than the UPPP group, but the efficacy was partly invalidated by the compliance rate of 62%.</p><p>Quality of life assessments in the dimensions of vitality, contentment and sleep improved in both groups at the one-year follow-up after treatment. There was no difference between the groups in terms of vitality and sleep. The UPPP group, however, reported a higher degree of contentment than the dental appliance group, even though the somnographic values were superior in the latter group. </p><p>Another aim was to conduct a randomised study to test the hypothesis that severe OSA patients will benefit from more pronounced mandibular advancement (MA) compared with a shorter advancement. Eighty-six males with severe OSA (AI>20) were randomly allocated to either 75% or 50% MA for a six-month treatment period. Treatment with a more pronounced mandibular advancement yielded a 20% higher normalisation rate than a shorter advancement. A mean normalisation rate of 45% was found for patients in this category with few side-effects, good patient satisfaction and a compliance of 92% after 6 months. </p><p>The overall conclusion is that dental appliance treatment is effective in patients with mild to moderate OSA and even for patients with severe OSA. The efficacy in terms of normalisation in patients with mild to moderate OSA was higher after the dental appliance treatment with a 50% degree of advancement than after the UPPP treatment. However, severe OSA patients might benefit from more pronounced advancement (75%) compared with a shorter degree of advancement (50%). QOL improved significantly after both dental appliance and UPPP treatment. </p>

Enthusiasm for uvulopalatopharyngoplasty (UPPP) in the treatment of mild-to-moderate obstructive sleep apnea syndrome (OSAS) has declined in recent years, partly because of a lower success rate over time and partly because of adverse effects. In more severe cases, the patients are generally treated with nasal continuous positive airway pressure (CPAP). However, many patients do not satisfactorily tolerate CPAP as a result of frequent side-effects. Consequently, there is a need for an alternative treatment. Reports on the beneficial effects of mandibular advancement appliances in the treatment of mild-to-moderate OSA exist in the form of short–term evaluations. One of the aims of the present thesis was to compare treatment effects with a mandibular advancement appliance and UPPP in patients with OSA with follow-up after one and four years. Ninety-five male patients with confirmed mild-to-moderate OSA (apnea index, AI &gt;5 and &lt;25) were randomised to treatment with a dental appliance or UPPP. Sleep studies were performed before and one and four years after intervention. According to the criteria for normalisation (AI&lt;5 and apnea hypopnea index, AHI&lt;10), 78% of the patients in the dental appliance group and 51% of the patients in the UPPP group had normalised after one year (p&lt;0.05). Still after four years of treatment, 63% of the patients in the dental appliance group and 33% of the patients in the UPPP group were normalised. The dental appliance group had a higher normalisation rate than the UPPP group, but the efficacy was partly invalidated by the compliance rate of 62%. Quality of life assessments in the dimensions of vitality, contentment and sleep improved in both groups at the one-year follow-up after treatment. There was no difference between the groups in terms of vitality and sleep. The UPPP group, however, reported a higher degree of contentment than the dental appliance group, even though the somnographic values were superior in the latter group. Another aim was to conduct a randomised study to test the hypothesis that severe OSA patients will benefit from more pronounced mandibular advancement (MA) compared with a shorter advancement. Eighty-six males with severe OSA (AI&gt;20) were randomly allocated to either 75% or 50% MA for a six-month treatment period. Treatment with a more pronounced mandibular advancement yielded a 20% higher normalisation rate than a shorter advancement. A mean normalisation rate of 45% was found for patients in this category with few side-effects, good patient satisfaction and a compliance of 92% after 6 months. The overall conclusion is that dental appliance treatment is effective in patients with mild to moderate OSA and even for patients with severe OSA. The efficacy in terms of normalisation in patients with mild to moderate OSA was higher after the dental appliance treatment with a 50% degree of advancement than after the UPPP treatment. However, severe OSA patients might benefit from more pronounced advancement (75%) compared with a shorter degree of advancement (50%). QOL improved significantly after both dental appliance and UPPP treatment.