The relationship between nasal airway size and nasal-oral breathing

Evaluating the threshold limit value of acceptable exposure concentration for exposure to bioaerosols in a wastewater treatment plant: Reverse-quantitative microbial risk assessment and sensitivity analysis

Agitation operations produce numerous pathogenic bioaerosols in WWTPs¹. QMRA² can determine risks of persons exposed to these bioaerosols. However, QMRA framework cannot help stakeholders in immediately deciding whether a risk is intolerable. Thus, evaluating threshold of acceptable exposure concentration is an urgent issue but is still rarely addressed in WWTPs. This study analyzed TLV³ benchmarks of E. coli and S. aureus bioaerosols emitted from a WWTP by reverse-QMRA. Furthermore, variance of input parameters was clarified by sensitivity analysis. Results showed that, under conservative and optimistic estimates, TLV of technicians was 1.52-2.06 and 1.26-1.68 times as large as those of workers, respectively; wearing mask drive TLV up to 1-2 orders of magnitude; TLV of M⁴ was at most 1.33 and 1.31 times as large as that of RD⁵, respectively. For sensitivity analysis, removal fraction by equipping PPE enlarge TLV for effortlessly obtaining an acceptable assessment result; exposure time was dominant when without PPE excepting the scenario of technicians exposed to E. coli bioaerosol. This study helps establish threshold guidelines for bioaerosols in WWTPs and contribute innovative perspectives for stakeholders.

What are the disease burden and its sensitivity analysis of workers exposing to Staphylococcus aureus bioaerosol during warm and cold periods in a wastewater treatment plant?

Biological treatment in wastewater treatment plants releases high amounts of pathogenic bioaerosols. Quantitative microbial risk assessment is a framework commonly used for quantitative risk estimation for occupational exposure scenarios. However, the quantitative contributions of health-risk-estimate inputted parameters remain ambiguous. Therefore, this research aimed to study the disease burden of workers exposed to Staphylococcus aureus bioaerosol during warm and cold periods and strictly quantify the contributions of the inputted parameters by sensitivity analysis on the basis of Monte Carlo simulation. Results showed that the disease health risk burden of workers in the warm period was 1.15-6.11 times higher than that of workers in the cold period. The disease health risk burden of workers without personal protective equipment was 23.83-36.55 times higher than that of workers with personal protective equipment. Sensitivity analysis showed that exposure concentration and aerosol ingestion rate were the first and second predominant factors, respectively; the sensitivity partitioning coefficient of the former was 1.17-1.35 times the value of the latter. In addition, no remarkable differences were revealed in the sensitivity percentage ratio between warm and cold periods. The findings could contribute to the mitigation measures for the management of public health risks.

The Impact of Mouth-Taping in Mouth-Breathers with Mild Obstructive Sleep Apnea: A Preliminary Study

Background: Many patients with obstructive sleep apnea (OSA) are mouth-breathers. Mouth-breathing not only narrows the upper airway, consequently worsening the severity of OSA, but also it affects compliance with nasal continuous positive airway pressure (CPAP) treatment. This study aimed to investigate changes in OSA by the use of mouth tape in mouth-breathers with mild OSA. Method: Mouth-breathers with mild OSA who met inclusion criteria and tolerated the sealing of the mouth were enrolled in the study. We used 3M silicone hypoallergenic tape was used to seal the mouths of the participants during sleep. The home sleep test (HST) used in this study was ApneaLink^®. Subjects received both a baseline HST and an outcome HST to be used 1 week later while their mouths were taped. The changes between the baseline and the outcome HSTs were compared, and the factors that influenced the differences in the sleep-test parameters after the shift of the breathing route were analyzed. A “responder” was defined as a patient who experienced a reduction from the baseline snoring index of at least 50% under mouth-taping in the HST; otherwise, patients were considered as having a poor response. Results: A total of 20 patients with mild OSA were included. Following the taping of the mouth, a good response was found in 13 patients (65%). The median apnea/hypopnea index (AHI) decreased significantly, from 8.3 to 4.7 event/h (by 47%, p = 0.0002), especially in supine AHI (9.4 vs. 5.5 event/h, p = 0.0001). The median snoring index (SI) was also improved (by 47%, 303.8 vs. 121.1 event/h, p = 0.0002). Despite no significant difference in the mean saturation, improvements in the oxygen desaturation index (8.7 vs. 5.8, p = 0.0003) and the lowest saturation (82.5% vs. 87%, p = 0.049) were noted. The change in AHI was associated with baseline AHI (r = −0.52, p = 0.02), oxygen desaturation index (ODI) (r = −0.54, p = 0.01), and SI (r = −0.47, p = 0.04). The change in SI was strongly associated with baseline SI (r = −0.77, p = 0.001). Conclusions: Mouth-taping during sleep improved snoring and the severity of sleep apnea in mouth-breathers with mild OSA, with AHI and SI being reduced by about half. The higher the level of baseline AHI and SI, the greater the improvement was shown after mouth-taping. Mouth-taping could be an alternative treatment in patients with mild OSA before turning to CPAP therapy or surgical intervention.

Analysis of conductive olfactory dysfunction using computational fluid dynamics

Conductive olfactory dysfunction (COD) is caused by an obstruction in the nasal cavity and is characterized by changeable olfaction. COD can occur even when the olfactory cleft is anatomically normal, and therefore, the cause in these cases remains unclear. Herein, we used computational fluid dynamics to examine olfactory cleft airflow with a retrospective cohort study utilizing the cone beam computed tomography scan data of COD patients. By measuring nasal–nasopharynx pressure at maximum flow, we established a cut-off value at which nasal breathing can be differentiated from combined mouth breathing in COD patients. We found that increased nasal resistance led to mouth breathing and that the velocity and flow rate in the olfactory cleft at maximum flow were significantly reduced in COD patients with nasal breathing only compared to healthy olfactory subjects. In addition, we performed a detailed analysis of common morphological abnormalities associated with concha bullosa. Our study provides novel insights into the causes of COD, and therefore, it has important implications for surgical planning of COD, sleep apnea research, assessment of adenoid hyperplasia in children, and sports respiratory physiology.

Primary site identification in children with obstructive sleep apnea by computational fluid dynamics analysis of the upper airway

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is a respiratory disorder caused by the obstruction of the upper airway during sleep. The identification of the primary site of OSA is essential to determine treatment strategy. This study aimed to establish computational fluid dynamics (CFD) analysis for determining the clinical severity of OSA and the primary site of OSA.

METHODS

Twenty children (mean age, 6 years) were divided into OSA and control groups according to their apnea-hypopnea index. Three-dimensional airways were constructed from computed tomography data. The pharyngeal airway morphology and the pressure and velocity of the upper airway were evaluated using CFD analysis.

RESULTS

The maximum velocity and negative pressure of the upper airway in the OSA group were significantly correlated with the severity of OSA (r_s = .741, P < .001; r_s = -.653, P = .002). A velocity higher than 12 m/s indicated the primary site of OSA. In addition, we found that the primary site of OSA is not necessarily the same as the collapsible conduit site.

CONCLUSIONS

CFD analysis allows both the evaluation of the disease severity of OSA and the identification of the primary site of OSA in children. The primary site of OSA is not necessarily the same as the collapsible conduit site; therefore, CFD analysis can be used to identify the appropriate intervention for treating OSA.

Predictors of oronasal breathing among obstructive sleep apnea patients and controls

Oronasal breathing may adversely impact obstructive sleep apnea (OSA) patients either by increasing upper airway collapsibility or by influencing continuous positive airway pressure (CPAP) treatment outcomes. Predicting a preferential breathing route would be helpful to guide CPAP interface prescription. We hypothesized that anthropometric measurements but not self-reported oronasal breathing are predictors of objectively measured oronasal breathing. Seventeen OSA patients and nine healthy subjects underwent overnight polysomnography with an oronasal mask with two sealed compartments attached to independent pneumotacographs. Subjects answered questionnaires about nasal symptoms and perceived breathing route. Oronasal breathing was more common (P = <0.001) among OSA patients than controls while awake (62 ± 44 vs. 5 ± 6%) and during sleep (59 ± 39 vs. 25 ± 21%, respectively). Oronasal breathing was associated with OSA severity (P = 0.009), age (P = 0.005), body mass index (P = 0.044), and neck circumference (P = 0.004). There was no agreement between objective measurement and self-reported breathing route among OSA patients while awake (κ = -0.12) and asleep (κ = -0.02). The breathing route remained unchanged after 92% of obstructive apneas. These results suggest that oronasal breathing is more common among OSA patients than controls during both wakefulness and sleep and is associated with OSA severity and anthropometric measures. Self-reporting is not a reliable predictor of oronasal breathing and should not be considered an indication for oronasal CPAP.NEW & NOTEWORTHY Continuous positive airway pressure (CPAP) interface choice for obstructive sleep apnea (OSA) patients is often guided by nasal symptoms and self-reported breathing route. We showed that oronasal breathing can be predicted by anthropometric measurements and OSA severity but not by self-reported oronasal breathing. Self-reported breathing and nasal symptoms should not be considered for CPAP interface choice.

Respiration Modulates Olfactory Memory Consolidation in Humans

In mammals respiratory-locked hippocampal rhythms are implicated in the scaffolding and transfer of information between sensory and memory networks. These oscillations are entrained by nasal respiration and driven by the olfactory bulb. They then travel to the piriform cortex where they propagate further downstream to the hippocampus and modulate neural processes critical for memory formation. In humans, bypassing nasal airflow through mouth-breathing abolishes these rhythms and impacts encoding as well as recognition processes thereby reducing memory performance. It has been hypothesized that similar behavior should be observed for the consolidation process, the stage between encoding and recognition, were memory is reactivated and strengthened. However, direct evidence for such an effect is lacking in human and nonhuman animals. Here we tested this hypothesis by examining the effect of respiration on consolidation of episodic odor memory. In two separate sessions, female and male participants encoded odors followed by a 1 h awake resting consolidation phase where they either breathed solely through their nose or mouth. Immediately after the consolidation phase, memory for odors was tested. Recognition memory significantly increased during nasal respiration compared with mouth respiration during consolidation. These results provide the first evidence that respiration directly impacts consolidation of episodic events, and lends further support to the notion that core cognitive functions are modulated by the respiratory cycle.SIGNIFICANCE STATEMENT Memories pass through three main stages in their development: encoding, consolidation, and retrieval. Growing evidence from animal and human studies suggests that respiration plays an important role in the behavioral and neural mechanisms associated with encoding and recognition. Specifically nasal, but not mouth, respiration entrains neural oscillations that enhance encoding and recognition processes. We demonstrate that respiration also affects the consolidation stage. Breathing through the nose compared with the mouth during consolidation enhances recognition memory. This demonstrates, first, that nasal respiration is important during the critical period were memories are reactivated and strengthened. Second, it suggests that the neural mechanisms responsible may emerge from nasal respiration.

Malocclusion and rhinitis in children: an easy-going relationship or a yet to be resolved paradox? A systematic literature revision

OBJECTIVE

The relation between nasal flow and malocclusion represents a practical concern to pediatricians, otorhinolaryngologists, orthodontists, allergists and speech therapists. If naso-respiratory function may influence craniofacial growth is still debated. Chronic mouth-breathing is reported to be associated also with a characteristic pattern of dental occlusion. On the other hand, also malocclusion may reduce nasal air flows promoting nasal obstruction. Hereby, the aim of this review was to describe the relationship between rhinitis and malocclusion in children.

METHODS

An electronic search was conducted using online database including Pubmed, Web of Science, Google Scholar and Embase. All studies published through to January 30, 2017 investigating the prevalence of malocclusion in children and adolescents (aged 0-20 years) affected by rhinitis and the prevalence of rhinitis in children with malocclusion were included. The protocol was registered at PROSPERO - International prospective register of systematic reviews under CRD42016053619.

RESULTS

Ten studies with 2733 patients were included in the analysis. The prevalence of malocclusion in children with rhinitis was specified in four of the studies ranging from as high as 78.2% to as low as 3%. Two out of the studies reported the prevalence of rhinitis in children with malocclusion with a rate ranging from 59.2 to 76.4%.

CONCLUSION

The results of this review underline the importance of the diagnosis and treatment of the nasal obstruction at an early age to prevent an altered facial growth, but the data currently available on this topic do not allow to establish a possible causal relationship between rhinitis and malocclusion.

Respiratory Polysomnographic Findings in Patients Treated Primarily for Unilateral Cleft Lip and Palate

Cleft lip and palate (CLP) is the most common congenital craniofacial abnormality. Obstructive sleep apnea syndrome (OSAS) is a highly prevalent but underdiagnosed disease and is frequently associated with craniofacial anomalies. There are few studies describing the sleep breathing pattern of children with CLP. This study sought to characterize the respiratory profile of 23 children with unilateral cleft lip and palate, aged 7-12 years, who had undergone cleft lip and nasal repair at age 3-4 months and palatoplasty at 12-15 months, with a particular focus on evaluating the presence of OSAS in children with CLP. Polysomnography was performed and findings were analyzed descriptively. We found a mean and median for apnea/hypopnea index (AHI) of 1.11/h (SD = 0.78) and 0.9/h, respectively. The mean obstructive apnea index (OAI) was 0.27/h (SD = 0.38) and the median, 0.1/h. Nearly 30% of patients had an AHI above 1.4 events/h. There was no significant oxyhemoglobin desaturation in the study group. In this group, the prevalence of OSAS was higher than in noncleft populations when compared to the normality values adopted. This sample of patients with unilateral cleft lip and palate exhibited an increased prevalence of OSAS during the mixed dentition stage. Although the results showed that OSAS was mild, we advise closer observation of these patients. Polysomnography is recommended for the assessment of children with airway abnormalities, to individualize the extent of treatment.

Airway Obstruction and the Unilateral Cleft Lip and Palate Deformity: Contributions by the Bony Septum

BACKGROUND

Patients with unilateral cleft lip and palate (CLP) deformities commonly develop nasal airway obstruction, necessitating septoplasty at the time of definitive rhinoplasty. We assessed the contribution of the bony septum to airway obstruction using computed tomography (CT) and cone beam CT (CBCT).

METHODS

A 2-year retrospective review of all subjects with unilateral CLP who underwent CBCT imaging (n = 22) and age-matched controls (n = 9) who underwent CT imaging was conducted. Control CT scans were used to determine the segment of nasal septum comprised almost entirely of bone. The CBCT of the nasal airway was assessed using Dolphin software to determine the contribution of the bony septum to septal deviation and airway obstruction.

RESULTS

The nasal septum posterior to the midpoint between anterior and posterior nasal spine is comprised of 96% bone. The nasal airway associated with this posterior bony segment was 43.1% (P < 0.001) larger by volume on the non-cleft side in patients with unilateral CLP. The average septal deviation within the posterior bony segment was 5.4 mm, accounting for 74.4% of the maximal deviation within the nasal airway. The average airway stenosis within the posterior bony nasal airway was 0.45 mm (0-2.2 mm).

CONCLUSIONS

In patients with unilateral CLP, the bony nasal septum can demonstrate significant deviation and airway stenosis. Surgeons should consider a bony septoplasty in their treatment algorithm in unilateral CLP patients who have reached skeletal maturity.

Assessment of public health risk associated with viral contamination in harvested urban stormwater for domestic applications

Capturing stormwater is becoming a new standard for sustainable urban stormwater management, which can be used to supplement water supply portfolios in water-stressed cities. The key advantage of harvesting stormwater is to use low impact development (LID) systems for treatment to meet water quality requirement for non-potable uses. However, the lack of scientific studies to validate the safety of such practice has limited its adoption. Microbial hazards in stormwater, especially human viruses, represent the primary public health threat. Using adenovirus and norovirus as target pathogens, we investigated the viral health risk associated with a generic scenario of urban stormwater harvesting practice and its application for three non-potable uses: 1) toilet flushing, 2) showering, and 3) food-crop irrigation. The Quantitative Microbial Risk Assessment (QMRA) results showed that food-crop irrigation has the highest annual viral infection risk (median range: 6.8×10(-4)-9.7×10(-1) per-person-per-year or pppy), followed by showering (3.6×10(-7)-4.3×10(-2)pppy), and toilet flushing (1.1×10(-7)-1.3×10(-4)pppy). Disease burden of each stormwater use was ranked in the same order as its viral infection risk: food-crop irrigation>showering>toilet flushing. The median and 95th percentile risk values of toilet-flushing using treated stormwater are below U.S. EPA annual risk benchmark of ≤10(-4)pppy, whereas the disease burdens of both toilet-flushing and showering are within the WHO recommended disease burdens of ≤10(-6)DALYspppy. However, the acceptability of showering risk interpreted based on the U.S. EPA and WHO benchmarks is in disagreement. These results confirm the safety of stormwater application in toilet flushing, but call for further research to fill the data gaps in risk modeling as well as risk benchmarks.

Dentofacial characteristics of oral breathers in different ages: a retrospective case-control study

BACKGROUND

This study aimed to investigate the dental and skeletal variables associated with disturbances of craniofacial development in oral-breathing (OB) individuals and the probability that these variables are related to this condition.

METHODS

This is an observational retrospective case-control study of 1596 patients divided into three groups of age n1 5-12, n2 13-18, and n3 19-57 years. Radiographic, clinical, and models data were analyzed. The control group was consisted of nasal breathing (NB) individuals. Statistical analyses of the qualitative data were performed with x (2) test to identify associations, and odds ratio (OR) tests were performed for the variables that the chi-square test (x (2)) identified an association.

RESULTS

In the descriptive analysis of the data, we observed that the class II malocclusion was the most frequent in the total sample, but when divided by age group and mode of breathing, there is a random division of these variables. In n1 group, class II, (OR = 2.02) short and retruded mandible (SM and RM) (OR = 1.65 and1.89) were associated with OB and it was considered a risk factor. In n2 group, class II (OR = 1.73), SM (OR = 1.87) and increased lower anterior height (ILAFH) (OR = 1.84) seemed to be associated and to be risk factors for OB. In the n1 group, decreased lower anterior facial height (DLAFH) and brachycephalic facial pattern (BP) seemed to be associated with NB and a protective factor against oral breathing.

CONCLUSIONS

This study showed that dental and skeletal factors are associated with OB in children, and it seems that it becomes more severe until adolescence. But adults showed no associations between OB and skeletal factors, only in dental variables, indicating that there is no cause-effect relationship between the dental and skeletal factors and OB. The treatment of nose breathing patient should be multidisciplinary, since OB remains even when dental and skeletal factors slow down.

Novel porous oral patches for patients with mild obstructive sleep apnea and mouth breathing: a pilot study

OBJECTIVES

Habitual open-mouth breathing (OMB) during sleep can cause snoring and obstructive sleep apnea (OSA). This study used a porous oral patch (POP) to treat patients with mild OSA and OMB during sleep. The subjective and objective outcomes were evaluated.

STUDY DESIGN

Prospective study.

SETTING

Tertiary referral center.

SUBJECTS AND METHODS

Patients with ≥5 events hourly but <15 hourly on the apnea-hypopnea index (AHI) were enrolled. All patients slept with their mouths closed by using the POP, which is a porous skin pad consisting of 3 layers: silicone sheet, polyurethane foam, and polyurethane film. Before treatment and during treatment, subjective outcomes were assessed using the Epworth Sleepiness Scale (ESS) and visual analog scale (VAS) of snoring. Objective outcomes were assessed using polysomnography and cephalometry.

RESULTS

Thirty patients were enrolled in this study. All patients slept with their mouths closed while using a POP. The ESS and VAS of snoring scores were 8.1 ± 1.5 and 7.5 ± 2.0 before the POP, respectively, in contrast to 5.2 ± 1.6 and 2.4 ± 1.4 while using a POP, respectively (P < .05). The median AHI score was significantly decreased by using a POP from 12.0 per hour before treatment to 7.8 per hour during treatment (P < .01). The snoring intensity and median snoring index were 49.1 ± 10.8 dB and 146.7 per hour before the POP, respectively, which decreased to 41.1 ± 7.8 dB and 40.0 per hour while using a POP, respectively (P < .01). Cephalometry revealed that the retropalatal space and retrolingual space were 7.4 ± 1.6 mm and 6.8 ± 2.5 mm before the POP, respectively, compared with 8.6 ± 1.2 mm and 10.2 ± 1.8 mm during treatment, respectively (P < .01).

CONCLUSION

The POP is a useful device to treat patients with mild OSA and habitual OMB.

Nasal and oral inspiration during natural speech breathing

PURPOSE

The purpose of this study was to determine the typical pattern for inspiration during speech breathing in healthy adults, as well as the factors that might influence it.

METHOD

Ten healthy adults, 18–45 years of age, performed a variety of speaking tasks while nasal ram pressure, audio, and video recordings were obtained. Inspirations were categorized as nasal-only, oral-only, simultaneous nasal and oral, or alternating nasal and oral inspiration. The method was validated using nasal airflow, oral airflow, audio, and video recordings for 2 participants.

RESULTS

The predominant pattern was simultaneous nasal and oral inspirations for all speaking tasks. This pattern was not affected either by the nature of the speaking task or by the phonetic context surrounding the inspiration. The validation procedure confirmed that nearly all inspirations during counting and paragraph reading were simultaneous nasal and oral inspirations, whereas for sentence reading, the predominant pattern was alternating nasal and oral inspirations across the 3 phonetic contexts.

CONCLUSIONS

Healthy adults inspire through both the nose and mouth during natural speech breathing. This pattern of inspiration is likely beneficial in reducing pathway resistance while preserving some of the benefits of nasal breathing.

Changes in the upper and lower pharyngeal airway spaces associated with rapid maxillary expansion

Objectives. The primary objectives of this retrospective study were first to compare the upper and lower pharyngeal airway spaces between orthodontic patients with and without maxillary constriction and second to evaluate the effect of rapid maxillary expansion (RME) on these airway spaces. A secondary objective was to compare the mode of breathing between groups. Materials and Methods. The experimental (RME) group consisted of 30 patients (mean age, 14.2 ± 1.3 years, 16 boys and 14 girls) with maxillary constriction who were treated with hyrax-type RME. The control group comprised the records of age- and gender matched patients (mean age, 13.8 ± 1.5 years, 16 boys and 14 girls) with no maxillary constriction but requiring nonextraction comprehensive orthodontic treatment. Cephalometric measurements in the sagittal dimension of upper and lower airway spaces for the initial and final records were recorded. Mode of breathing and length of treatment were also compared. Results. The sagittal dimension of the upper airway increased significantly in the RME group (mean = 1.3 mm) compared to the control group (mean = 0.5 mm), P = 0.016. However, there was no significant difference in the lower pharyngeal airway measurement between the RME group (mean = 0.2) and the control group (mean = 0.4), P = 0.30. There was no significant difference with respect to mode of breathing between the two groups (P = 0.79). Conclusion. Rapid maxillary expansion (RME) during orthodontic treatment may have a positive effect on the upper pharyngeal airway, with no significant change on the lower pharyngeal airway.

Evaluation of upper airway obstruction in Class II children with fluid-mechanical simulation

INTRODUCTION

The purpose of this study was to test the null hypothesis that dolichofacial and brachyfacial children with Class II malocclusion do not differ in upper airway obstruction. Furthermore, the ability of fluid-mechanical simulation to detect airway obstruction within the limitations of simulation was examined.

METHODS

Forty subjects from 7 to 11 years of age with Class II malocclusion participated and were divided into 2 groups, dolichofacial and brachyfacial, based on their Frankfort mandibular plane angles. Cone-beam computed tomography images supplied the shape of the entire airway. Two measures of respiratory function, air velocity and pressure, were simulated by using 3-dimensional images of the airway. The images and simulations were compared between the 2 facial types.

RESULTS

The size of the upper airway did not differ statistically between facial types; however, the simulated maximal pressure and velocity of the dolichofacial type were significantly higher than those of the brachyfacial type.

CONCLUSIONS

Airway obstruction differs with the Frankfort mandibular plane angle, even though the depth and cross-sectional area of the airway do not. The fluid-mechanical simulation system developed in this study detected differences in airway obstruction that were not apparent from morphologic studies.

Avaliação do efeito da expansão rápida da maxila no padrão respiratório, por meio da rinomanometria anterior ativa: descrição da técnica e relato de caso

A finalidade deste artigo é avaliar o efeito da expansão rápida da maxila (ERM) no padrão respiratório. Por intermédio de um caso clínico, será relatado como indivíduos com atresia da maxila e problemas respiratórios podem se beneficiar com a expansão rápida da maxila. Outro aspecto que deve-se salientar é como profissionais da área da saúde, principalmente ortodontistas e otorrinolaringologistas, têm à sua disposição exames complementares para o diagnóstico do paciente com "Respiração Bucal"

Rhinometric evaluation of nasal cavity geometry and its relation to the upper arch transverse distance

The objective of this study was to evaluate children's respiratory patterns in the mixed dentition, by means of acoustic rhinometry, and its relation to the upper arch width development. Fifty patients were examined, 25 females and 25 males with mean age of eight years and seven months. All of them were submitted to acoustic rhinometry and upper and lower arch impressions to obtain plaster models. The upper arch analysis was accomplished by measuring the interdental transverse distance of the upper teeth, deciduous canines (measurement 1), deciduous first molars (measurement 2), deciduous second molars (measurement 3) and the first molars (measurement 4). The results showed that an increased left nasal cavity area in females means an increased interdental distance of the deciduous first molars and deciduous second molars and an increased interdental distance of the deciduous canines, deciduous first and second molars in males. It was concluded that there is a correlation between the nasal cavity area and the upper arch transverse distance in the anterior and mid maxillary regions for both genders.

Avaliação do espaço aéreo faríngeo por meio da tomografia computadorizada de feixe cônico

INTRODUÇÃO: a avaliação do espaço aéreo superior faz parte da rotina na elaboração do diagnóstico e plano de tratamento ortodôntico. A radiografia cefalométrica em norma lateral tem sido usada rotineiramente na avaliação da permeabilidade do espaço aéreo, esbarrando na limitação de fornecer uma imagem bidimensional de uma estrutura tridimensional. A Tomografia Computadorizada de Feixe Cônico (TCFC) tem entrado na realidade ortodôntica trazendo um arsenal de informações concernentes ao espaço aéreo superior. Por fornecer uma imagem tridimensional, possibilita determinar de maneira precisa a área de maior estreitamento da faringe, que ofereceria maior resistência à passagem aérea. OBJETIVOS: o propósito deste artigo é esclarecer o ortodontista quanto aos recursos disponíveis na TCFC para o diagnóstico de possíveis barreiras físicas que possam diminuir a permeabilidade das vias aéreas superiores.

Computed tomographic evaluation of mouth breathers among paediatric patients

OBJECTIVES

Mouth breathing causes many serious problems in the paediatric population. It has been maintained that enlarged adenoids are principally responsible for mouth breathing. This study was designed to evaluate whether other mechanical obstacles might predispose the child to mouth breathing.

METHODS

67 children with ages ranging from 10 to 15 years were studied and grouped into mouth-breathers and nose-breathers. The children first underwent axial CT scans of the brain for which they were originally referred. In addition, they were subjected to a limited coronal CT examination of the paranasal sinuses. Congenital anatomical variations as well as inflammatory changes were assessed.

RESULTS

87% of mouth-breathing children had hypertrophied adenoids, 77% had maxillary sinusitis, 74% had pneumatized middle concha, 55% had a deviated nasal septum, 55% had hypertrophied inferior conchae, 45% had ethmoidal sinusitis and 23% showed frontal sinusitis. Such changes were significantly less prevalent in nose-breathers. 12.9% of mouth-breathing children did not have adenoids. Of these children, only 3.3% had one or more congenital or inflammatory change whereas the other 9.6% showed a completely normal CT scan signifying the incidence of habitual non-obstructive mouth breathing.

CONCLUSIONS

It is clear that adenoids have a dominant role in causing mouth breathing. Yet, we recommend that paediatricians should assess other mechanical obstacles if mouth breathing was not corrected after adenoidectomy. Further research should be performed to test the validity of correction of such factors in improving the quality of life of mouth-breathing children.

Long-Term Effects of Rapid Maxillary Expansion on Nasal Area and Nasal Airway Resistance

Background

Rapid maxillary expansion (RME) may improve the nasal respiratory pattern. This study was performed to evaluate the effect of RME on the nasal cavity by acoustic rhinometry and computed rhinomanometry and to determine nasal and maxillary width by posteroanterior cephalometric radiography, up to 30 months after the orthodontic procedure.

Methods

Twenty-seven children with oral breathing, ranging in age from 7 to 10 years, and with mixed dentition were selected. The children had unior bilateral posterior crossbite involving deciduous canines and the first permanent molars. All subjects were submitted to nasofibroscopy, acoustic rhinometry, and computed rhinomanometry and posteroanterior cephalometric radiography at four different times, i.e., before expansion, immediately, 90 days and 30 months after expansion.

Results

The mean linear left-to-right nasal cavity lateral prominence and left-to-right jugal points cephalometric measures increased considerably after expansion and this increase was maintained throughout the period of evaluation. There was an immediate significant decrease in nasal resistance, up to 90 days after RME, but the nasal resistance increased 30 months after the procedure. The acoustic rhinometry results did not show any difference in values throughout time.

Conclusion

RME significantly increased nasal and maxillary width as measured by frontal cephalometry, but the nasal mucosal effects were more subtle. Also, the influence of RME on nasal resistance was not stable, and nasal resistance values returned to close to the initial ones after 30 months.

Avaliação da influência do tipo facial nos tamanhos dos espaços aéreos nasofaríngeo e bucofaríngeo

INTRODUÇÃO: a diminuição no tamanho do espaço aéreo nasofaríngeo, causada pela hipertrofia da tonsila faríngea, tem sido associada a alterações no padrão normal de crescimento craniofacial e a efeitos deletérios na oclusão. OBJETIVOS: avaliar variações nos tamanhos dos espaços aéreos nasofaríngeo e bucofaríngeo de acordo com o padrão de crescimento craniofacial, a correlação entre os tamanhos dos espaços e o índice VERT, além de verificar um possível dimorfismo sexual. MÉTODOS: foi utilizado um total de 90 telerradiografias laterais de pacientes, divididos em três grupos: meso, braqui e dolicofacial, determinados por meio do índice VERT de Ricketts. Os pacientes da amostra, com idades entre 9 e 16 anos, apresentavam padrão respiratório nasal, sem qualquer tipo de obstrução. RESULTADOS: não foi verificada variação estatisticamente significante nos tamanhos dos espaços aéreos nasofaríngeo e bucofaríngeo, quando comparados os três tipos faciais. Também não foi encontrada correlação entre os tamanhos dos espaços aéreos e os valores do índice VERT de Ricketts dos pacientes e não houve dimorfismo sexual. CONCLUSÕES: pode-se descartar a influência do tipo facial nos tamanhos dos espaços aéreos nasofaríngeo e bucofaríngeo.

Head posture in cleft lip and palate patients with oronasal fistula and its relationship with craniofacial morphology

OBJECTIVE

This study aimed to evaluate the relationship between head posture and craniofacial morphology in nonsyndromic cleft lip and palate children with oronasal fistula.

PATIENTS

A total of 31 cleft lip and palate patients with a mean skeletal age of 7.59 (+/-2.11) years were involved. Fifteen had complete unilateral cleft lip and palate, 13 had complete bilateral cleft lip and palate, and three had complete cleft palate. Each of the cleft patients was matched with a noncleft Class I subject, on the basis of sex and skeletal age.

DESIGN

Lateral cephalograms were taken of all subjects in the standardized upright posture and in orthoposition. Sixteen postural parameters and 44 morphological parameters were evaluated.

RESULTS

The correlations with the cranio-cervical and mandibulo-cervical parameters indicated a trend of retrusion in the incisors with extention of the head. The positive nontopographical relationship between the nasolabial angle and some of the postural parameters supplemented the retrusion tendency in the upper incisors with head extension. Vertical skeletal morphological parameters correlated with the postural parameters. Cranio-cervical parameters seemed to be mostly related to mandibular position.

CONCLUSION

Most of the cranio-cervical parameters measured confirmed an increased cranio-cervical angulation in the cleft sample when compared to controls. This head posture change was associated with alterations in tooth position and craniofacial morphology when comparisons were made to the control group.

Effect of rapid maxillary expansion on the dimension of the nasal cavity and on nasal air resistance

INTRODUCTION

Atresia of the maxilla is a transverse skeletal dysplasia, possibly associated with respiratory problems. For its correction, rapid maxillary expansion is a feasible orthodontic process.

OBJECTIVE

To evaluate the effect of rapid maxillary expansion on the nasal cavity by acoustic rhinometry and computed rhinomanometry.

MATERIAL AND METHODS

Twenty-nine children of both sexes with oral and/or mixed breathing, ranging in age from 7 to 10 years and with mixed dentition were selected. The children had uni- or bilateral posterior crossbite involving deciduous canines and the first permanent molars and were not being submitted to any otorhinolaryngologic or orthodontic treatment. All subjects were submitted to rhinologic exams and orthodontic documentation at three different times, i.e., before expansion and immediately and 90 days after expansion.

RESULTS

There was no difference in the minimal cross-sectional area at the level of the valve and inferior nasal turbinate between the periods analyzed, but there was a statistically significant reduction in nasal resistance after expansion.

CONCLUSION

On the basis of the present results, we may conclude that rapid maxillary expansion may lessen the nasal resistance. Although there was no difference in nasal geometry. Thus, this procedure may improve nasal respiration, but cannot be indicated for this purpose by itself.

Electromyographic activity evaluation and comparison of the orbicularis oris (lower fascicle) and mentalis muscles in predominantly nose- or mouth-breathing subjects

INTRODUCTION

The objective of this study was to evaluate and compare the electromyographic (EMG) activity of the orbicularis oris--lower fascicle (LOO) muscle and the mentalis muscle (MT)--in predominantly nose-breathing (PNB) and mouth-breathing (PMB) subjects.

METHODS

Thirty-four subjects, 22 PNB and 12 PMB, with Class II Division 1 malocclusions were evaluated in 2001 (T1) and again in 2004 (T2), 2 years 5 months later. The age ranges of the sample were 11 years to 14 years 11 months at T1, and 13 years 4 months to 16 years 6 months at T2. EMG activity was recorded with bipolar surface electrodes at rest and during 12 movements; data were processed and normalized by the EMG highest value. The Student t test and the Mann-Whitney nonparametric test were used to compare the mean values and the variables between the observation times.

RESULTS

Greater EMG activity of the MT was observed in the PMB group at rest and swallowing at T1 and T2. At T2, increased EMG activity of the LOO at blowing and pronunciation of the phoneme \b\ was observed as well as a greater increment of EMG activity of this muscle at blowing, pronunciation of the phoneme \m\, and chewing in the PMB group. In addition, greater EMG activity of the MT at chewing in the PMB group was observed at T2.

CONCLUSIONS

These results suggest that mouth breathing influences EMG activity of the LOO and MT muscles.

Reproducibility of airway dimensions and tongue and hyoid positions on lateral cephalograms

INTRODUCTION

The aim of this study was to evaluate the reproducibility of airway dimensions and tongue and hyoid positions on lateral cephalometric radiographs.

METHODS

Three lateral cephalograms each of 30 patients were obtained in natural head positions at 30-minute intervals. Twelve measurements, including pharyngeal airway dimensions and tongue and hyoid positions, were taken. The relationships between 3 sets of measurements were evaluated by using repeated analysis of variance, Dahlberg's method error formula, and correlation coefficient.

RESULTS

No statistically significant differences were found between the 3 sets of measurements with the repeated analysis of variance (P > .05). Correlation coefficient values ranged between 0.964 (vertical position of the hyoid) and 0.683 (hypopharyngeal airway width). The average method error was 1.22 mm.

CONCLUSIONS

The results suggest that airway dimension and tongue- and hyoid-position measurements are highly reproducible on natural-head-position cephalograms.

Infant oral health and oral habits

Many oral diseases and conditions, including dental caries (cavities) and malocclusions, have their origins early in life. Prudent anticipatory guidance by the medical and dental professions can help prevent many of the more common oral health problems. This article provides information on the rationale for early dental examination and instructions for pediatric and family practitioners in scheduling and conducting an early oral intervention appointment. In addition, feeding practices, non-nutritive sucking, mouth breathing, and bruxing are discussed, including their effects on orofacial growth and development.

Perceptual and physiologic effects of histamine challenge on nasal breathing

The purpose of this study is to determine the effect of histamine-induced nasal congestion on nasal airflow and the perception of externally applied resistance to nasal breathing. Nasal cross-sectional area and nasal airflow during free breathing were measured in 15 adult subjects before and after histamine challenge. The threshold for perception of resistance to nasal breathing was determined using a dynamic perturbator device, with both free breathing and controlled nasal air-flow. The average threshold for perception of nasal resistance was 0.383 Pa/cm3/s at baseline. After histamine application, there was a significant decrease in nasal cross-sectional area (p = 0.0001), associated with a decrease in nasal airflow (r = 0.6). The average threshold of perception increased to 1.373 Pa/cm3/s (p < 0.0001). When nasal airflow was controlled at the baseline rate, the threshold of perception improved to 0.638 Pa/cm3/s (p = 0.024). These findings indicate that nasal congestion causes a reduction in both nasal airflow and the perception of resistance to nasal breathing. The ability to detect nasal airway impairment is improved with increased nasal airflow. An improved understanding of the physiology of the subjective perception of nasal patency may lead to innovative methods for the treatment of nasal obstruction.

Long-term follow-up of early treatment of unilateral forced posterior cross-bite. Orofacial status

Twenty-nine subjects, 20 years old on average and all treated at 4 years of age for unilateral forced posterior dento-alveolar cross-bite by grinding or by expansion of the upper dental arch, were clinically examined to evaluate the long-term effects of their treatment. The frequency of successful treatment-indicated as stable correction of the cross-bite-by means of only 1 treatment sequence was 59%; by grinding, 57%; and by expansion, 60%. The 18 subjects that had only been treated at the age of 4 years formed the 'early group' in our study. Eleven of our subjects had been retreated later in the mixed or permanent dentition because of a relapse of the unilateral forced posterior cross-bite and formed the 'late group'. A significantly higher frequency of mouth breathing, breathing obstacles, and snoring was found in this group. According to our clinical investigation, 2 of the subjects in our cohort still had a unilateral forced posterior cross-bite. Our findings regarding masticatory performance, bite force, and endurance showed no significant differences between the initial cross-bite and the healthy sides or between the early and the late group subjects, which showed that the masticatory function of the treated subjects was symmetrical. Grinding and expansion treatments seem to display similar success rates in the long-term regarding correction of unilateral posterior forced cross-bite.

Effect of changes in the breathing mode and body position on tongue pressure with respiratory-related oscillations

The purpose of this study was to examine whether tongue pressure on the lingual surface of the mandibular incisors shows respiratory-related changes, with particular attention paid to its relationship to genioglossus electromyographic activity, and to determine the effect of changes in the mode of breathing and body position on tongue pressure. Tongue pressure was recorded with a miniature pressure sensor incorporated in a custom-made intraoral appliance in nine male subjects in different breathing modes and body positions. Electromyographic activity of the genioglossus muscle and respiratory-related movement were recorded simultaneously. Tongue pressure showed respiratory-related cyclic oscillations, with a maximum value during expiration and a minimum value during inspiration. In contrast, the activity of the genioglossus muscle showed a maximum amplitude during inspiration and a minimum amplitude during expiration. The maximum tongue pressure during oral breathing was significantly greater (P <.01) than during nasal breathing in both the upright and supine positions. Changes in body position significantly affected the maximum tongue pressure during oral breathing. The activity of the genioglossus muscle changed significantly with different breathing modes and body positions. Changes in the position of the hyoid bone produced by changes in the breathing mode and body position appear to have a critical role in determining tongue pressure.

Variation of nasal respiratory pattern with age during growth and development

The purpose of this study was to determine changes in nasal respiratory pattern with growth and development, particularly to determine the age where upper airway growth ceases. The results on 361 healthy subjects, aged 7 to 24 years, based on aerodynamic measurements during rest breathing, showed clear differences between inspiratory and expiratory phases. Nasal airflow rate and cross-sectional area increased and oral-nasal pressure and nasal resistance decreased with age up to the age of 16, levelling by the age of 20 years. The body size and gender had effect only on nasal airflow rate. This study suggests that the measurements of the nasal respiratory pattern, determining impaired nasal airway, should be done during inspiration and using age-related assesment from a healthy population until the age of 16 years. From then on, guidelines for adults are applicable.

Dyspnea following experimentally induced increased nasal airway resistance

Nasal resistance (NRZ) values for healthy adults range from 1.0 to 3.5 cm H2O/L/sec. Some oral breathing tends to occur at values above 3.5. The purpose of the present study was to determine at what level of NRZ individuals sense that nasal breathing is difficult. A diaphragm was used to add four different resistance loads in random to 15 adult subjects. These loads were 5,8, and 15 cm H2O/L/sec and a value 40% above the individual's normal NRZ. Loads were added under four conditions: normal breathing, fixed flow rate, fixed breathing rate, and fixed flow and breathing rate. The pressure-flow technique was used to measure NRZ under all conditions. The study revealed that the sensation of breathing difficulty occurred at a median resistance of 5 cm H2O/L/sec and, as subjects were constrained to maintain fixed flow and breathing rates, the magnitude of RZ, at which the sensation of dyspnea was noted, decreased. The values observed in this study support previous findings suggesting that individuals switch to some oral breathing to maintain an adequate level of upper airway resistance at values between 3.5 and 4.5 cm H2O/L/sec. The findings also show that individuals attempt to minimize increases in airway resistance by modifying breathing behaviors.

Monitoring nasal and oral airway patency

The hypothesis that upper airway breathing behaviors generally follow the rules of a physiologic regulating system implies the existence of sensors that monitor the airway environment. The purpose of this study was to assess the sensitivity of the monitoring system to sudden changes in airway patency in healthy, adult subjects. An instrument capable of changing airway dimensions in about 10 ms was used to assess psychophysical recognition and physiologic responses to sudden changes in airway size. Our results indicate that psychophysical recognition of change in patency occurred at a mean constriction area of 0.31 cm2. These findings suggest that recognition of change in airway size occurs well before the airway becomes flow-limiting or severely obstructed.

Temporal variation in nasal and oral breathing in children

The purpose of this study was to measure several variables associated with respiratory function at repeated intervals. The temporal variation of these variables was assessed within persons and within the sample population. Twenty-nine children, 18 boys and 11 girls, between the ages of 7 and 13 years of age, participated. Each subject attended three separate appointments. At each appointment, the percentage nasal breathing was measured three times with inductive plethysmography. The nasal resistance and smallest nasal cross-sectional area were measured once at each appointment with posterior rhinomanometry. The findings suggest a significant amount of variation in repeated measurements of respiratory variables. More variation was noted in measurements taken on different days than within 1 day. No correlation was present between either nasal resistance or nasal cross-sectional area in relation to percentage of nasal breathing. All subjects had a nasal component of respiration; no one was a 100% oral breather. No correlation was observed between age or gender of the subjects and any of the respiratory variables measured.

Open-mouth posture and maxillary arch width in young children: a three-year evaluation

A large biracial sample of children were assessed for open mouth posture and maxillary arch width once a year for 3 years. Analyses revealed that although the youngsters exhibited open-mouth posture at high levels, over time, there was a significant decrease in this behavior. Racial and gender differences, as well as a race-by-time interaction, were also evidenced. The children displayed a significant increase in maxillary arch width across time, with gender and racial differences seen in this growth pattern. Finally, when the youngsters were classified as exhibiting primarily open-mouth or closed-mouth posture, it was observed that children with open-mouth posture displayed a significantly slower pattern of maxillary growth compared with children who display anterior lip seal posture. The implications of the findings were discussed.

An improved method for airway assessment in children

Respiratory mode determination using the simultaneous nasal and oral respirometric technique (SNORT) or a head-out body plethysmography can be time-consuming, expensive, and intimidating to children. We have developed an improved method for assessing respiratory mode that uses inductive plethysmography linked to a menu-driven computer program that circumvents some of these problems. An assessment of 29 subjects over as many as nine separate time points suggests that respiratory mode measurements remain fairly uniform in some children, but can vary significantly in others.

Rhinometry and open-mouth posture in young children

A biracial sample of 348 elementary school children who were in the first grade were assessed for open-mouth posture (OMP) in the natural environment. In addition, rhinometry was performed on 296 of the children. Means were computed for percent OMP and cross-sectional nasal airway. Results indicated that, in general, these children exhibited relatively high rates of OMP. Boys displayed significantly greater OMP than girls, and black children showed significantly larger cross-sectional nasal areas than white children. A significant correlation between OMP and nasal area only was evident for children exhibiting OMP during more than 80% of the observation intervals. The implications of the findings were discussed.

Age and gender effects on nasal respiratory function in normal subjects

One hundred and ninety-seven normal individuals between the ages of 5 and 73 years were evaluated to determine nasal resistance, nasal cross-sectional area, and respiratory mode during quiet breathing. Subjects were categorized into three age groups. Nasal resistance and respiratory mode were directly determined using posterior rhinomanometry and the SNORT technique, respectively. Nasal cross-sectional area was estimated using the hydrokinetic equation. Results indicated significant effects of age on all variables; significant gender differences were found for respiratory mode. Weak correlations were found between respiratory mode and nasal resistance. The results are presented as normative data on nasorespiratory characteristics to facilitate diagnostic and treatment decisions relative to individuals with normal morphology as well as to patients with craniofacial anomalies. A fundamental issue of both clinical and theoretical importance arising from the study pertains to the definitions of normality and impairment.

Nasal airway in breathing and speech

Clefts of the lip and palate frequently produce nasal deformities that tend to reduce the size of the nasal airway. Approximately 70% of the cleft population have nasal airway impairment and about 80% "mouth-breathe" to some extent. Surgical correction of nasal, palatal, and pharyngeal structures may further compromise breathing. Type of cleft appears to affect airway size, with unilateral clefts demonstrating the smallest airway. Although a pharyngeal flap may further decrease airway size, some individuals do not notice a postoperative change because of airway compromise prior to flap placement. Speech is a modified breathing behavior that uses the respiratory system to provide an energy source and involves structures within the respiratory tract to modulate this energy into meaningful sounds. The oral, nasal, and pharyngeal structures that are affected by cleft lip and palate during breathing are often compromised for speech as well. The nasal airway plays an important role in controlling speech pressures when velopharyngeal function is impaired. A "good" nose for breathing is often a "bad" nose for speech under such circumstances.

Is nasal airway size a marker for susceptibility toward clefting?

Johnston and Hunter (1989) reported that in monozygotic twins discordant for cleft lip +/- palate, the noncleft twins demonstrated what appeared to be a bimodal distribution of nasal cavity width. Two thirds showed reduced airway size and one third showed normal or slightly greater airway size. They suggested that the two-thirds group may represent reduced size of the medial nasal prominences and the other may represent underdevelopment of the maxillary prominence. We were particularly interested in the findings because the difference in distribution may represent differences in pathogenesis and therefore have etiologic significance. With this in mind we assessed nasal cross-sectional areas in 37 subjects with cleft lip or cleft lip +/- palate using the pressure-flow technique during breathing. A group of 72 noncleft individuals served as controls. As expected, the data revealed that subjects with clefts had a significantly reduced nasal airway (p = .0001). More important, the distribution of nasal airway size in the cleft group was similar to that reported by Johnston and Hunter (1989). This comparability suggests that it may be possible to assign most cleft lip +/- palate patients to a particular group. Since heredity may differ among the two groups (Chung et al., 1986), we may have a simple technique to assess the risk of occurrence for cleft lip +/- palate.

Nasal airway impairment: the oral response in cleft palate patients

The purpose of this study was to assess the oral response to severe nasal airway impairment in patients with cleft palate. Inductive plethysmography was used to measure the percent of nasal breathing, and the pressure-flow technique was used to estimate nasal area in 15 persons with severe nasal airway impairment. Mean nasal area was 0.17 cm2, and the average percent of nasal breathing was 20%. Analysis revealed a strong correlation (0.87) between nasal size and percent of nasal breathing in this selected group. Modeling studies based on the mean values from the subjects' data indicated that the model "mouth" would have to open 0.5 cm2 to shunt 80% of the airflow orally, an amount equivalent to the mean value of the subjects' respiratory mode. More important, the extrapolated data revealed that upper-airway resistance decreased in the model from 8.7 cm H2O/L/sec to a level of 3.2 cm H2O/L/sec, which is an average value for healthy adults. These data support the concept that the mouth acts as a variable resistor to maintain an optimal respiratory tract resistance when the nasal airway is impaired.

Relationship between vertical dentofacial morphology and respiration in adolescents

The relationship between vertical dentofacial morphology and respiration has been debated and investigated from various approaches. The purpose of this study was to use contemporary respirometric techniques to compare the breathing behavior of normal and long-faced adolescents. Sixteen normal and 32 long-faced subjects 11 to 17 years of age were chosen clinically and verified by means of a discriminant function. Vertical and anteroposterior facial form was assessed from lateral cephalometric radiographs according to the following measurement criteria: six skeletal angular, eight skeletal linear, four dental linear, and three skeletal ratios. Breathing behavior was quantified according to tidal volume, minimum cross-sectional nasal area, and percent of nasal breathing as assessed by pneumotachography, measurement of differential pressures, and inductive plethysmography. The data indicated that the normal and long-faced groups were significantly different with respect to lower face form, and each group in the study was comparable to groups that had been chosen by previous investigators. Multiple regression analysis demonstrated that the normal and long-faced groups had similar tidal volumes and minimum nasal cross-sectional areas, but the long-faced subjects had significantly smaller components of nasal respiration. These results illustrate that groups without significant differences in airway impairment can have significantly different breathing modes that may be behaviorally based, rather than airway-dependent.