Introduction: This dissertation aims to explore, in a clinical setting, the effectiveness of pursed lips breathing (PLB), in the management of dyspnoea in stable COPD. Methodology: A mixed methodology that comprised a randomised controlled trial (RCT), a predominantly qualitative follow-up (FU) study and two measurement studies was used. The RCT intervention group was taught PLB at home over 8 weeks. Primary outcome measures were the Self Report Chronic Respiratory Disease Questionnaire (CRQ-SR) dyspnoea and mastery domains and Endurance Shuttle Walk Test (ESWT). The FU study investigated the long-term experience of PLB in a subset of RCT participants through telephone interview, focus group and observation of PLB technique at home visit. Prior to the RCT a study using limits of agreement (LoA) methodology was conducted to investigate reliability of hand-held spirometric measurement of inspiratory capacity (IC) with a view to using it as an outcome measure. Following the RCT a retrospective analysis of data collected from the ESWT was performed comparing a 1-walk protocol with the published 2-walk protocol. Results: Forty-one patients with COPD were recruited to the RCT (PLB n = 22, control n =19); mean age 68 years (SD 11), mean FEV1% predicted 47% (SD 15.80) and 13 were approached to participate in the FU; 11 of 13 agreed to telephone interview, 5 to attend the focus group and 6 to home visit. The median time since learning PLB was 17 months (6 - 23). The RCT found no statistically significant difference between groups in the primary outcome measures and in retrospect was insufficiently powered. Post hoc analysis found effect sizes for primary outcome measures were: CRQ-SR dyspnoea 0.05, CRQ-SR mastery 0.48 and ESWT 0.44. For secondary outcome measures the PLB group showed a significant (p = 0.02) improvement in oxygen saturation on ESWT. Long-term follow-up found 9 of 11 still used PLB, 8 reported definite benefit. Those using PLB used it for breathlessness with four themes identified: use of PLB with physical activity (8/11), to increase confidence and reduce panic (4/11), as an exercise (3/11), at night (3/11). Discontinuation of PLB (2/11) was due to no benefit. Hand-held spirometric measurement of IC found LoA for same-day IC measurement in healthy volunteers (n = 20) ± 0.630L (95%CI ± 0.255) and over 3 weeks (n = 11) ± 0.560L (95%CI ± 0.326). In COPD, same day LoA (n = 26) were ± 0.582L (95%CI ± 0.169) and over 6 weeks (n = 8) ± 0.486L (95%CI ± 0.302). Retrospective analysis of ESWT data identified that completion rates improved by 17% for the 1-walk protocol but that the ceiling-effect was 12.2% compared to 7.3% for the 2-walk protocol. LoA between protocols when measuring change over time (n = 31) was ±80% (95%CI 25.56); less than the difference described as "somewhat better" (113%) following pulmonary rehabilitation (PR) but greater than the m.c.i.d. of 68%. Conclusions: LoA for IC exceeded the clinically significant reported 0.3L; the protocol tested here was not sufficiently reliable for use as an outcome measure. Analysis of ESWT data showed the 1-walk protocol was adequate for identify change in clinical practice but, for research purposes the 2-walk protocol should be retained. From the RCT learning PLB resulted in reduced physiological stress with respect to oxygen desaturation when performing ESWT compared to the control group. Long-term follow-up showed that, in severe COPD perceived benefits persisted in 62% of patients.

The purpose of this study was to evaluate the effects of a computer program on the training and maintenance of diaphragmatic breathing. The biofeedback portion was visual computer training and the results were displayed concurrently with participants' breathing responses to monitor display. The verbal feedback portion was praise that was given and recorded when participants responded with predominantly diaphragmatic breathing at the scheduled moment and response instruction that was given when participants responded with predominantly thoracic breathing. The results of this study indicate the computer program's effectiveness needs to be increased by supplementation with verbal feedback.

A model was developed to predict the increased physiological effort of wearing a respiratory protective device. Specifically, the model was designed to predict the effects of varying ventilatory demands on eleven respiratory variables of the man-respirator system, breath frequency (f_b), tidal volume (V_t), inspiratory flow (dvi/dt), expiratory flow (dve/dt), inspiratory mask pressure (P_mi), expiratory mask pressure (P_me), inspiratory intrathoracic pressure (P_ii), expiratory intrathoracic pressure (P_ie), inspiratory mask work (W_mi), expiratory mask work (W_me), and mask leakage index (L_i). The model was tested by experiment in which three male subjects underwent maximal exercise testing with and without the "pressure-demand" respirator. The eleven variables were determined for each thirty second period utilizing on-line computer analysis. Application of the model to these experimental conditions resulted in significant (p<.001) relationships between each of the predicted and observed variables.

Radiation therapy is a cancer treatment method that employs high-energy radiation beams to destroy cancer cells by damaging the ability of these cells to reproduce. Thoracic and abdominal tumors may change their positions during respiration by as much as three centimeters during radiation treatment. The prediction of respiratory motion has become an important research area because respiratory motion severely affects precise radiation dose delivery. This study describes recent radiotherapy technologies including tools for measuring target position during radiotherapy and tracking-based delivery systems. In the first part of our study we review three prediction approaches of respiratory motion, i.e., model-based methods, model-free heuristic learning algorithms, and hybrid methods. In the second part of our work we propose respiratory motion estimation with hybrid implementation of extended Kalman filter. The proposed method uses the recurrent neural network as the role of the predictor and the extended Kalman filter as the role of the corrector. In the third part of our work we further extend our research work to present customized prediction of respiratory motion with clustering from multiple patient interactions. For the customized prediction we construct the clustering based on breathing patterns of multiple patients using the feature selection metrics that are composed of a variety of breathing features. In the fourth part of our work we retrospectively categorize breathing data into several classes and propose a new approach to detect irregular breathing patterns using neural networks. We have evaluated the proposed new algorithm by comparing the prediction overshoot and the tracking estimation value. The experimental results of 448 patients’ breathing patterns validated the proposed irregular breathing classifier.

Os indivíduos portadores de desproporções maxilomandibulares apresentaram características miofuncionais orais peculiares ao tipo de desproporção que apresentam. Anormalidades na relação dento-esquelética acarretam prejuízos estéticos e funcionais aos indivíduos, tais como a modificação do espaço anatômico da cavidade oral, que pode vir a desencadear problemas na fala e na voz, assim como prejuízos na respiração. O objetivo do estudo é compreender as características respiratórias e fonoarticulatórias em indivíduos com deformidades dentofaciais submetidos a preparo ortodôntico pré-cirúrgico e verificar se há diferenças entre esses indivíduos comparativamente a indivíduos com equilíbrio dentofacial. Participaram 60 indivíduos de 18 a 40 anos de idade, 30 portadores de deformidades dentofaciais e 30 de um grupo controle. A avaliação da fonoarticulação foi realizada por meio da diadococinesia (DDC) das emissões /pa/, /ta/, /ka/, /pataka/, /a/ e /i/; Tempo Maximo de Fonação (TMF) durante a emissão de /a/, /i/, /u/, /s/, /z/ e contagem de números; avaliação da respiração, incluindo as medidas da capacidade vital e coordenação pneumofonoarticulatória, por meio da espirometria. Foram utilizados os programas computadorizados Sound Forge (Sony), Mult Speech Main Program e Motor Speech Profile Advanced (Kay Elemetrics) e o espirômetro PonyFx. O teste t de Student foi utilizado para comparação dos resultados entre osindivíduos com DDF e os indivíduos com equilíbrio dentofacial, adotando-se o nível de significância de 5%. Os indivíduos com DDF produziram menor número de emissões por segundo comparados ao grupo controle nas seguintes emissões da DDC: sílaba ka para o total de indivíduos (p=0,049), sequência pataka para o subgrupo Padrão III (p=0,012) e para mulheres (p=0,001). Os parâmetros relacionados à irregularidade dos ciclos de algumas emissões da DDC foram produzidas com valores mais elevados pelos indivíduos com DDF do que o grupo controle : maior coeficiente de variação da intensidade da silaba ta para o total de indivíduos (p=0,016) e para o subgrupo Padrão III (p=0,023); maior valor de desvio-padrão do período da sílaba pa para o total de indivíduos (p=0,046) e para o as mulheres (p=0,036); maior valor de desvio-padrão do período da sílaba ta no subgrupo Padrão III (p=0,047) e para o total de indivíduos (p=0,032); maior valor de perturbação do período da silaba pa para o total de indivíduos (p=0,024) e para as mulheres (p=0,031); maior valor de desvio padrão do período da vogal ï para as mulheres (p=0,027). Em relação ao TMF, os indivíduos com DDF apresentaram valores inferiores do que os indivíduos com equilíbrio dentofacial nas emissões: s para o subgrupo Padrão II (p=0,005) e homens (p=0,019); z para o subgrupo Padrão II (p=0,009); contagem de números para os homens (p=0,044). As medidas extraídas pela espirometria foram semelhantes entre os indivíduos com e sem DDF. Concluiu-se que foram encontradas diferenças entre indivíduos com deformidades dentofaciais, comparativamente a indivíduos com equilíbrio dentofacial, quanto à velocidade, e diversos parâmetros de estabilidade da DDC oral e quanto ao desvio-padrão do período da DDC laríngea. O grupo de pacientes com DDF não apresentou características respiratórias diferentes do grupo controle, mas apresentou valores reduzidos de TMF em emissões que contêm fonemas consonantais. / Individuals presented with maxillomandibular disproportions will show oral miofunctional characteristics peculiar to the type of disproportion they exhibit. Abnormalities in the dento-skeletal relation lead to aesthetic and functional losses, such as modification of the anatomical space of the oral cavity, which may trigger problems in ones voice, and in syllable production, as well as breathing damages.This study aims at understanding the respiratory and phonoarticulatory characteristics in individuals presented with dentofacial deformities, submitted to presurgical orthodontic preparation and verify whether there are differences among individuals presented with dentofacial deformities, as compared to individuals with dentofacial balance. Sixty subjects, in the age range 18 - 40 years, 30 presented with dentofacial deformities and 30 of a control group, participated in the study. Phonoarticulation assessment was performed through diadochokinesia (DDC) of emissions /pa/, /ta/, /ka/, /pataka/, /a/ and /i/; Maximum Time of Phonation (MTP) during the emission of /a/, /i/, /u/, /s/, /z/ and number counting; breathing assessment, including measurements of vital capacity and pneumophonoarticulatory coordination, through spirometry. Softwares Sound Forge (Sony), Mult Speech Main Program and Motor Speech Profile Advanced (Kay Elemetrics) and PonyFx spirometer, were utilized. Student´s t test was used for comparison between the results of individuals presented with DFD and those of individuals with dentofacial balance, by adopting the 5% significance level. Subjects presented with DFD produced a smaller number of emissions, per second, as compared to the control group, in the following DDC emissions: syllable ka for the total of individuals (p=0,049), sequence pataka for the Pattern III subgroupI (p=0,012) and for women (p=0,001). Some DDC emissions were produced with more elevated values by individuals presented with DFD, than the control group, regarding the parameters related to the irregularity of the cycles: greater intensity variation coefficient of the syllable ta for the total of individuals (p=0,016) and for the Pattern III subgroup (p=0,023); greater standard variation value of the pa syllable period for the total of subjects (p=0,046) and for the women (p=0,036); greater SD value of the ta syllable period in the Pattern III subgroup (p=0,047) and for the total of individuals (p=0,032); greater disturbance value of the pa syllable period for the total of individuals (p=0,024) and for the women (p=0,031); greater SD value of the vowel ï period for the women (p=0,027). In relation to Maximum phonation time (MPT), the individuals with DFD presented lower values than subjects with dentofacial balance in the emissions: s for the Pattern II subgroup (p=0,005) and men (p=0,019); z for Pattern II subgroup (p=0,009); counting of numbers for men (p=0,044). The measurements extracted through spirometry were similar among individuals with and without DFD. Differences were found between individuals with dentofacial deformities and individuals with dentofacial balance, as to the speed, and several stabiliity parameters of oral DDC and as to the SD of laryngeal DDC. The group of patients with DFD did not present respiratory characteristics different from those of the control group, but presented reduced MPT values in emissions which contain consonant phonemes.

INTRODUÇÃO: A respiração oral pode acarretar alterações estruturais e funcionais do sistema estomatognático. As causas mais freqüentes da respiração oral são as obstruções nasais e/ou faríngeas e dentre as obstruções nasais, a rinite alérgica é uma doença cuja incidência vem aumentando. Apesar de haver uma relação direta entre a rinite alérgica e a obstrução nasal e desta com alterações funcionais do sistema estomatognático, são poucos os estudos que investigaram a presença destas alterações em pacientes com rinite alérgica. OBJETIVO: o objetivo deste trabalho foi verificar a presença de alterações das funções de respiração, mastigação, deglutição e fala em pacientes com rinite alérgica e relacioná-las com a intensidade dos sintomas da rinite. MÉTODOS: Esta pesquisa baseou-se em um estudo no qual foram avaliados, consecutivamente, 170 pacientes, de ambos os sexos, com faixa etária entre 6 e 55 anos de idade. Estes pacientes foram divididos em dois grupos: grupo rinite (GR): 85 pacientes com diagnóstico de rinite alérgica persistente e grupo controle (GC): 85 pacientes sem histórico, queixa ou sinais clínicos de obstrução nasal, independente da etiologia e pareados por sexo e idade ao GR. Após a formação dos grupos, os pacientes foram divididos em três subgrupos de acordo com a faixa etária: crianças, 6 a 11 anos; adolescentes, 12 a 18 anos e adultos, 19 a 55 anos. Todos os pacientes passaram por avaliação otorrinolaringológica, fonoaudiológica e oclusal. Foram colhidos os dados referentes às funções de respiração, mastigação, deglutição e fala e dados da consulta médica. Os dados foram comparados e analisados estatisticamente. RESULTADOS: A diferença dos escores de sinais e sintomas entre GR e GC mostrou-se estatisticamente significante. Quando comparada a presença de alteração nas funções estudadas entre GR e GC, foi observada diferença estatisticamente significante no modo respiratório e nos padrões de mastigação e deglutição. A correlação existente entre o escore de obstrução nasal e a presença de alteração funcional foi significante na análise do modo respiratório e do padrão de mastigação. CONCLUSÕES: O paciente com rinite alérgica apresenta alterações funcionais do sistema estomatognático e o aumento do escore de obstrução nasal pode ser considerado um indicativo destas alterações. / INTRODUCTION: the mouth breathing can cause structural and functional alterations on the stomatognathic system. The most frequent causes of mouth breathing are nasal and/or pharyngeall obstructions. Amongst nasal obstructions, allergic rhinitis is a disease which has been spreading. Even though there is a direct relation between rhinitis and nasal obstruction and the latter with functional and orthodontic alterations, few are the studies which observed such alterations in patients with rhinitis. AIM: the aim of this essay was to verify the alterations in respiration, mastication, deglutition, speaking and orthodontic changes present in patients with allergic rhinitis and relate it to the intensity of the symptoms of rhinitis. METHODS: One hundred and seventy (170) patients of both sexes of ages ranging from 6 to 55 years were evaluated. These patients were divided into two groups: rhinitis group (RG): 85 patients with diagnosis of persistent allergic and control group (CG): 85 patients without a history, complaints or clinical signs of nasal obstruction, regardless of etiology and paired by and age with the RG. Each patient was submitted to an otorhinolaryngologic, speech pathologic and orthodontical evaluation. Functional\'s data referring were gathered, as well as data from the medical and orthodontic evaluation. The data were compared and statistically analysed. RESULTS: Otorhinolaryngologic evaluation revealed a significant diference of symptoms\' score between GR and GC. Speech pathologic assessment showed a higher incidence of open lips in patients with allergic rhinitis accompanied by important impairment in mastication and deglutition. Orthodontic evaluation demonstrated a significant difference in occlusal characteristics between GR and GC. We observed significant relation between the score of nasal obstruction and the intensity of respiration and chewing\'s alteration. CONCLUSIONS: the patient with allergic rhinitis displays orthodontic and functional changes and the increase of the nasal obstruction\'s score can be used like an indicative of those alterations.

by Emil, Chiu Hong Man. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1993. / Includes bibliographical references (leaves 108-118). / Acknowledgment --- p.6 / List of Abbreviations --- p.7 / Summary --- p.8 / Chapter Chapter 1 --- Childhood Asthma - An Overview --- p.10 / Chapter 1.1 --- Definition of childhood asthma --- p.10 / Chapter 1.2 --- Basic Pathophysiology of Asthma --- p.11 / Chapter 1.2.1 --- Airway obstruction --- p.11 / Chapter 1.2.2 --- Airway inflammation --- p.11 / Chapter 1.2.3 --- Bronchial hyperresponsiveness --- p.12 / Chapter 1.2.4 --- Trigger factors of asthma --- p.12 / Chapter 1.3 --- Measurement of the severity of asthma --- p.14 / Chapter 1.3.1 --- Obj ective measures of lung function --- p.14 / Chapter 1.3.2 --- Measures of bronchial hyperresponsiveness --- p.15 / Chapter 1.3.3 --- Clinical measures --- p.16 / Chapter 1.4 --- Epidemiology --- p.16 / Chapter 1.5 --- Treatment of asthma --- p.19 / Chapter 1.5.1 --- Pharmacological treatment --- p.19 / Chapter 1.5.2 --- Non-pharmacological treatment --- p.20 / Chapter 1.5.3 --- Behavioral Intervention --- p.24 / Chapter 1.5.4 --- Summary of treatment of asthma --- p.28 / Chapter Chapter 2 --- Change in Lung Mechanic During Asthmatic Attack --- p.29 / Chapter 2.1 --- Asthmatic Attack --- p.29 / Chapter 2.2 --- Hyperinflation of the lungs during asthmatic attack --- p.30 / Chapter 2.3 --- Effect of hyperinflation on respiratory muscle function --- p.32 / Chapter Chapter 3 --- Biofeedback Intervention --- p.36 / Chapter 3.1 --- Background --- p.36 / Chapter 3.2 --- Definition of biofeedback --- p.36 / Chapter 3.3 --- Biofeedback as an adjunctive treatment to asthma --- p.37 / Chapter 3.3.1 --- Direct airways biofeedback --- p.38 / Chapter 3.3.2 --- Muscle EMG biofeedback --- p.41 / Chapter 3.4 --- Justification of study --- p.45 / Chapter Chapter 4 --- Material and Methods --- p.47 / Chapter 4.1 --- Study design and patients recruitment --- p.47 / Chapter 4.2 --- Equipment and measurement --- p.49 / Chapter 4.2.1 --- Biofeedback unit and the computer system --- p.49 / Chapter 4.2.2 --- Mini Wright flow meter --- p.50 / Chapter 4.2.3 --- Clinical measures --- p.50 / Chapter 4.2.4 --- Bronchial provocation test --- p.51 / Chapter 4.3 --- Biofeedback training --- p.53 / Chapter 4.3.1 --- Preparation of the patient --- p.53 / Chapter 4.3.2 --- Training Procedures --- p.54 / Chapter 4.3.3 --- Criteria for successful training --- p.55 / Chapter 4.4 --- Statistical methods --- p.56 / Chapter Chapter 5 --- Results --- p.58 / Chapter 5.1 --- Immediate training effects --- p.58 / Chapter 5.1.1 --- Comparison between the successful group and the fail group --- p.59 / Chapter 5.1.2 --- Combining successful and fail groups as the training group --- p.63 / Chapter 5.2 --- One year follow-up --- p.65 / Chapter 5.2.1 --- Social and clinical characteristics of both training and control group --- p.65 / Chapter 5.2.2 --- Clinical characteristic --- p.66 / Chapter 5.2.3 --- Attack rate --- p.66 / Chapter 5.2.4 --- The Fscore --- p.67 / Chapter 5.2.5 --- Score --- p.67 / Chapter 5.2.6 --- Mscore --- p.68 / Chapter 5.2.7 --- Bronchial hyperresponsiveness --- p.68 / Chapter 5.2.8 --- Lung functions --- p.69 / Chapter Chapter 6 --- Discussion --- p.95 / Chapter 6.1 --- Physiological effects --- p.95 / Chapter 6.1.1 --- EMG --- p.96 / Chapter 6.1.2 --- Pulse rate and skin temperature --- p.97 / Chapter 6.1.3 --- Lung functions --- p.97 / Chapter 6.2 --- Clinical outcomes --- p.100 / Chapter 6.2.1 --- Attack rate and symptom --- p.100 / Chapter 6.3 --- Clinical implication of study --- p.101 / Chapter 6.4 --- Limitation and difficulties --- p.103 / Chapter 6.5 --- Suggestions for further study --- p.104 / Chapter Chapter 7 --- Conclusions --- p.105 / References --- p.108 / Appendix1 --- p.119 / Appendix2 --- p.120 / List of Figures --- p.122 / List of Tables --- p.124

"This thesis presents a real-time noncontact system that can monitor an infant's respiration and detect apnea when it occurs. For infants, bedside monitoring of respiratory signals using non-contact sensors is desirable at the hospital and for in-home care. Traditional approach employs acoustic sensors which can hardly detect infant breathing due to low SNR. In this thesis, a novel method is introduced by using a ultra-wideband (UWB) radar that obtains breathing signal from an infant's weak chest vibration. Furthermore, advanced signal processing techniques are proposed to monitor the breathing signal and to detect apnea. Since an infant may move in the crib, a location algorithm is applied periodically to track the current location of the infant's chest. An apnea warning is issued when the respiration is absent for a pre-defined period of time."

Objetivos: avaliar o efeito dos padrões ventilatórios reexpansivos associados ao biofeedback respiratório (BFR) sobre a função pulmonar, força muscular respiratória e hábitos em respiradores bucais funcionais. Métodos: foram avaliadas 60 crianças respiradoras bucais funcionais (RBF), divididas em Grupo Experimental e Controle, sendo o Grupo Experimental submetido a 15 sessões de padrões ventilatórios reexpansivos associados ao BFR por meio do biofeedback pletsmovent (MICROHARD® V1.0), o qual proporciona o biofeedback dos movimentos tóraco-abdominais e o Grupo Controle submetido ao mesmo número de sessões realizando apenas o biofeedback. Espirometria, medidas das pressões respiratórias máximas estáticas e questões para avaliação de hábitos, respondidas pelos responsáveis pelas crianças, foram realizadas antes e após a terapia. Teste t de Student para dados pareados e testes não paramétricos, com nível de significância de 5%, foram utilizados para análise. Resultados: Foram observados alterações significativas na capacidade vital forçada (FVC), índice de Tiffeneau (IT), pressão expiratória máxima (PEmáx), pressão inspiratória máxima (PImáx) e nos hábitos avaliados em RBF com o uso do BFR associado aos padrões reexpansivos. Não foram observadas diferenças significantes quando comparados o Grupo Experimental e o Controle. Conclusão: Os resultados permitem concluir que o BFR associado aos padrões reexpansivos melhora a capacidade vital forçada, IT, força da musculatura respiratória e hábitos em RBF, podendo ser, portanto, utilizado como uma das formas de terapia nesses indivíduos / Objectives: Assess the effect of re-expansive respiratory patterns associated to respiratory biofeedback (RBF) on pulmonary function, respiratory muscle strength and habits in individuals with functional mouth breathing (FMB). Methods: Sixty children with FMB were divided into experimental and control groups. The experimental group was submitted to 15 sessions of re-expansive respiratory patterns associated to RBF (biofeedback pletsmovent; MICROHARD® V1.0), which provided biofeedback of the thoracic and abdominal movements. The control group was submitted to 15 sessions using biofeedback alone. Spirometry, maximum static respiratory pressure measurements and questions regarding habits (answered by parents/guardians) were carried out before and after therapy. The Student\'s t-test for paired data and non-parametric tests were employed for statistical analysis at a 5% level of significance. Results: Significant changes were found in forced vital capacity, Tiffeneau index scores, maximum expiratory pressure, maximum inspiratory pressure and habits assessed in FMB with the use of RBF associated to the re-expansive patterns. No significant differences were found comparing the experimental and control groups. The results allow the conclusion that RBF associated to re-expansive patterns improves forced vital capacity, Tiffeneau index scores, respiratory muscle strength and habits in FMB and can therefore be used as a form of therapy for such individuals.

As deformidades dentofaciais (DDF) compreendem alterações no equilíbrio dentofacial que comprometem a estética e a funcionalidade do sistema estomatognático. O crescimento e desenvolvimento craniofacial são influenciados pela respiração, porém as condições respiratórias nesses indivíduos são pouco abordadas na literatura. O presente trabalho teve por objetivo caracterizar a função respiratória de indivíduos com deformidade dentofacial em relação às vias aéreas superiores e inferiores, bem como aos aspectos da respiração voltados para a fonação, neste mesmo grupo de indivíduos. Para isso foram avaliados 40 indivíduos adultos, divididos em três grupos equilibrados de acordo com gênero e idade: GC (14 indivíduos com equilíbrio dentofacial, Classe I e Padrão I); DDFII (12 indivíduos com DDF, Classe II e Padrão II) e DDFIII (14 indivíduos, Classe III e Padrão III), estando os dois últimos em tratamento ortodôntico preparatório para a cirurgia ortognática. Os pacientes foram submetidos ao exame miofuncional orofacial para avaliação de tipo e modo respiratório, fluxo nasal e possibilidade de uso nasal, utilizando o Protocolo MBGR, bem como à espirometria para avaliação da capacidade respiratória. Foi realizada, ainda, a medida de fluxo aéreo expiratório utilizando espelho milimetrado e calculada a área de embaçamento provocado pelo fluxo. Também foi obtido tempo de fonação de /s/. Na comparação entre os grupos foram utilizados os testes Kruskall-Wallis e teste t; para a comparação entre os aspectos estudados foram aplicados os testes estatísticos Qui Quadrado e ANOVA; para correlações, utilizou-se Pearson e Spearman. Os resultados demonstraram maior ocorrência do tipo respiratório médio superior para os diferentes grupos. No que diz respeito ao modo, mais da metade dos participantes com DDF apresentou respiração oronasal ou oral, sendo que ao realizar a comparação entre os grupos, foi encontrada diferença entre o DDFII e os demais grupos estudados (p<0,001). Quanto ao fluxo expiratório nasal, a maioria dos indivíduos dos grupos DFFII e DDFIII apresentou fluxo reduzido unilateralmente, enquanto para o GC foi simétrico, tendo-se verificado diferença significante entre os grupos com DDF e GC (p=0,011). Quanto à possibilidade de uso nasal, os grupos DFFII e DFFIII apresentaram semelhanças, porém o grupo DFFII apresentou menor tempo de uso nasal em relação aos outros grupos (p<0,001). No escore do Protocolo MBGR, o grupo DFFII apresentou os escores mais altos, ou seja, os piores resultados, ao comparar com os demais grupos (p<0,001). Com relação aos exames objetivos (área do embaçamento do espelho de Altmann, capacidade vital e suporte de ar disponível), a análise estatística não evidenciou diferença significante entre os grupos para todos os aspectos considerados (p>0,05). Por fim, foi encontrada correlação negativa quanto ao tempo fonatório de /s/ e o escore do MBGR correspondente à função respiratória. Concluiu-se que os grupos com DDF apresentam semelhante tipo respiratório, capacidade vital e menor suporte respiratório para a fonação, se comparados ao GC. Além disso, foi verificado que os indivíduos com DDF apresentam modo respiratório oral/oronasal, possibilidade de uso nasal reduzida e menor fluxo expiratório nasal, sendo que os prejuízos na função respiratória influenciaram a utilização do ar para a fonação. / Dentofacial deformities (DFD) are comprised of alterations of the dentofacial balance that compromise the aesthetics and functionality of the stomatognathic system. Craniofacial growth and development are influenced by breathing, however, the conditions of the upper and lower airways in these individuals are poorly addressed in the literature. The present study aimed to characterize the respiratory function in individuals with dentofacial deformities in relation to the upper and lower airways, as well as the aspects of breathing focused on phonation in this same group of individuals. To do so, we evaluated 40 adult individuals who were divided into three groups, balanced by gender and age: GC (14 individuals with dentofacial balance, Class I and Standard I); DFDII (12 individuals, Class II and Standard II) and DFDIII (14 individuals, Class III and Standard III), the latter two in preparatory orthodontic treatment for orthognathic surgery. The subjects were submitted to an Orofacial Myofunctional examination for the evaluation of respiratory type and mode, nasal flow and potential of nasal ability as well as spirometry to evaluate the respiratory capacity. We even performed a measure of expiratory airflow using a graded mirror and calculated the area of haze caused by the flow in cm2, utilizing the Image Pro Plus program. A phonation time of /s/ was also obtained. The qualitative and quantitative variables were submitted to the statistical Chi Square and ANOVA tests, respectively, for the comparison between the groups we utilized the Kruskal-Wallis and t-test, and for the correlations we utilized the Pearson and Spearman tests. The results showed that regarding the respiratory tract, the most prevalent was the upper middle for the different groups. With respect to the mode, more than half of the participants with dentofacial deformities presented oro-nasal or oral breathing, and when performing a comparison between the groups, a difference was found between the DFDII and the other studied groups (p<0.001). With regards to the nasal expiratory flow, most individuals from the DFFII and DDFIII groups showed a reduced flow to the right or to the left, while the GC group was symmetrical, and significant differences were verified between the groups with DFD and GC (p=0.011). Regarding the possibility of nasal use, the DFDII and DFDIII groups presented similarities, however, the DFDII group presented the highest occurrence of possibility of nasal use under one minute when compared to the other groups (p<0.001). In the MBGR Protocol score, the DFDII group had the highest scores, in other words, the worst results when compared to the other groups (p<0.001). With regard to the objective tests (area of haze of the Altmann mirror, vital capacity and available air support), the statistical analysis presented no significant differences between the groups for all aspects considered (p>0.05). Finally, a negative correlation was found regarding the phonation time of /s/ and the MBGR score. It was concluded that individuals with DFD presented an oral / oronasal respiratory mode, a possibility of reduced nasal use, reduced expiratory nasal flow and medium / high respiratory type. Furthermore, it was verified that groups with DFD presented similar vital capacity and lower respiratory support for phonation, when compared to the GC group.