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Schwab RJ, Lin TC, Wiemken A, Dedhia RC, Wehrli FW, Keenan BT. State-Dependent Biomechanical Behavior of Oropharyngeal Structures in Apneic and Control Subjects: A Proof-of-Concept Study. Ann Am Thorac Soc 2024; 21:949-960. [PMID: 38507612 PMCID: PMC11160136 DOI: 10.1513/annalsats.202309-847oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 03/20/2024] [Indexed: 03/22/2024] Open
Abstract
Rationale: Apneic individuals have reduced airway caliber during sleep. The biomechanical changes in upper airway anatomy contributing to this airway narrowing are largely unknown. Objectives: We sought to investigate the state-dependent (wake vs. sleep) biomechanical behavior of the upper airway soft-tissue and craniofacial structures. Methods: Upper airway magnetic resonance imaging was performed in 15 sleep-deprived control subjects (apnea-hypopnea index, <5; 0.3 ± 0.5 events per hour) and 12 sleep-deprived apneic subjects (apnea-hypopnea index, ⩾5; 35.2 ± 18.1 events per hour) during wake and sleep and analyzed for airway measures and soft-tissue/mandibular movement. Results: In the retropalatal region, control subjects showed sleep-dependent reductions (P ⩽ 0.037) in average cross-sectional airway area (CSA), minimum CSA, and anteroposterior and lateral dimensions. Apneic subjects showed sleep-dependent reductions (P ⩽ 0.002) in average CSA, minimum CSA, and anteroposterior and lateral dimensions. In the retroglossal region, control subjects had no sleep-dependent airway reductions. However, apneic subjects had sleep-dependent reductions in minimal CSA (P = 0.001) and lateral dimensions (P = 0.014). Control subjects only showed sleep-dependent posterior movement of the anterior-inferior tongue octant (P = 0.039), whereas apneic subjects showed posterior movement of the soft palate (P = 0.006) and all tongue octants (P ⩽ 0.012). Sleep-dependent medial movement of the lateral walls was seen at the retropalatal minimum level (P = 0.013) in control subjects and at the retropalatal and retroglossal minimum levels (P ⩽ 0.017) in apneic subjects. There was posterior movement of the mandible in apneic subjects (P ⩽ 0.017). Conclusions: During sleep, control and apneic subjects showed reductions in retropalatal airway caliber, but only the apneic subjects showed retroglossal airway narrowing. Reductions in anteroposterior and lateral airway dimensions were primarily due to posterior soft palate, tongue and mandibular movement and to medial lateral wall movement. These data provide important initial insights into obstructive sleep apnea pathogenesis.
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Affiliation(s)
| | - Theodore C. Lin
- Division of Sleep Medicine, Department of Medicine
- Department of Otorhinolaryngology – Head and Neck Surgery, Temple University, Philadelphia, Pennsylvania
| | | | - Raj C. Dedhia
- Division of Sleep Medicine, Department of Medicine
- Department of Otorhinolaryngology – Head and Neck Surgery, and
| | - Felix W. Wehrli
- Laboratory for Structural, Physiologic, and Functional Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania; and
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Gou D, Zhu Q, Chan HK, Kourmatzis A, Cheng S, Yang R. Effects of the deformation and size of the upper airway on the deposition of aerosols. Int J Pharm 2024; 657:124165. [PMID: 38663643 DOI: 10.1016/j.ijpharm.2024.124165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 04/16/2024] [Accepted: 04/22/2024] [Indexed: 05/02/2024]
Abstract
Aerosol drug delivery in the human airway is significantly affected by the morphology and size of the airway. This work developed a CFD-DEM model to simulate and analyze air flow and powder dynamics in combined inhaler-airway systems with different degrees of airway deformation (non-deformed, 50%, and 75% deformed) and sizes (adult, 0.80, and 0.62 scaled). The airways were generated based on a regular airway constructed from the MRI images through finite element method (for deformed airways) or scaling-down (for smaller airways). The airways were connected to Turbuhaler® through a connector. The results showed that under the same flow rate, the variation in the airway geometry and size had a minimum impact on the flow field and powder deposition in the device and the connector. However, deformation caused more particle deposition in the deformed region. Notably, the airway with 50% deformation had the most particles passing through the airway with the largest particle sizes due to its lower air velocity in the deformed area. Reducing airway size resulted in more powder deposition on the airway, particularly at the pharynx and mouth regions. This was because, with the same flow rate, the flow velocity in the smaller airway was higher, causing more particle-wall collisions in the mouth and pharynx regions. More importantly, the deposition efficiency in the 0.62-scaled airway was significantly higher than the other two airways, highlighting the importance of the different administration of aerosol drugs for young children.
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Affiliation(s)
- Dazhao Gou
- School of Materials Science and Engineering, UNSW Sydney, NSW 2052, Australia
| | - Qixuan Zhu
- School of Materials Science and Engineering, UNSW Sydney, NSW 2052, Australia
| | - Hak-Kim Chan
- Advanced Drug Delivery Group, Sydney Pharmacy School, The University of Sydney, NSW 2006, Australia
| | - Agisilaos Kourmatzis
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006, Australia
| | - Shaokoon Cheng
- School of Engineering, Macquarie University, NSW 2109, Australia
| | - Runyu Yang
- School of Materials Science and Engineering, UNSW Sydney, NSW 2052, Australia.
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Jugé L, Liao A, Yeung J, Knapman FL, Bull C, Burke PG, Brown EC, Gandevia SC, Eckert DJ, Butler JE, Bilston LE. Regional associations between inspiratory tongue dilatory movement and genioglossus activity during wakefulness in people with obstructive sleep apnoea. J Physiol 2023; 601:5795-5811. [PMID: 37983193 PMCID: PMC10953361 DOI: 10.1113/jp285187] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 10/20/2023] [Indexed: 11/22/2023] Open
Abstract
Inspiratory tongue dilatory movement is believed to be mediated via changes in neural drive to genioglossus. However, this has not been studied during quiet breathing in humans. Therefore, this study investigated this relationship and its potential role in obstructive sleep apnoea (OSA). During awake supine quiet nasal breathing, inspiratory tongue dilatory movement, quantified with tagged magnetic resonance imaging, and inspiratory phasic genioglossus EMG normalised to maximum EMG were measured in nine controls [apnoea-hypopnea index (AHI) ≤5 events/h] and 37 people with untreated OSA (AHI >5 events/h). Measurements were obtained for 156 neuromuscular compartments (85%). Analysis was adjusted for nadir epiglottic pressure during inspiration. Only for 106 compartments (68%) was a larger anterior (dilatory) movement associated with a higher phasic EMG [mixed linear regression, beta = 0.089, 95% CI [0.000, 0.178], t(99) = 1.995, P = 0.049, hereafter EMG↗/mvt↗]. For the remaining 50 (32%) compartments, a larger dilatory movement was associated with a lower phasic EMG [mixed linear regression, beta = -0.123, 95% CI [-0.224, -0.022], t(43) = -2.458, P = 0.018, hereafter EMG↘/mvt↗]. OSA participants had a higher odds of having at least one decoupled EMG↘/mvt↗ compartment (binary logistic regression, odds ratio [95% CI]: 7.53 [1.19, 47.47] (P = 0.032). Dilatory tongue movement was minimal (>1 mm) in nearly all participants with only EMG↗/mvt↗ compartments (86%, 18/21). These results demonstrate that upper airway dilatory mechanics cannot be predicted from genioglossus EMG, particularly in people with OSA. Tongue movement associated with minimal genioglossus activity suggests co-activation of other airway dilator muscles. KEY POINTS: Inspiratory tongue movement is thought to be mediated through changes in genioglossus activity. However, it is unknown if this relationship is altered by obstructive sleep apnoea (OSA). During awake supine quiet nasal breathing, inspiratory tongue movement, quantified with tagged magnetic resonance imaging (MRI), and inspiratory phasic genioglossus EMG normalised to maximum EMG were measured in four tongue compartments of people with and without OSA. Larger tongue anterior (dilatory) movement was associated with higher phasic genioglossus EMG for 68% of compartments. OSA participants had an ∼7-times higher odds of having at least one compartment for which a larger anterior tongue movement was not associated with a higher phasic EMG than controls. Therefore, higher genioglossus phasic EMG does not consistently translate into tongue dilatory movement, particularly in people with OSA. Large dilatory tongue movements can occur despite minimal genioglossus inspiratory activity, suggesting co-activation of other pharyngeal muscles.
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Affiliation(s)
- Lauriane Jugé
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
- Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
| | - Angela Liao
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
- Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
| | - Jade Yeung
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
| | - Fiona L. Knapman
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
- Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
| | - Christopher Bull
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
- Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
| | - Peter G.R. Burke
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
- Macquarie Medical SchoolFaculty of Medicine and Health SciencesMacquarie UniversitySydneyNew South WalesAustralia
| | - Elizabeth C. Brown
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
- Prince of Wales HospitalSydneyNew South WalesAustralia
| | - Simon C. Gandevia
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
- Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
| | - Danny J. Eckert
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
- Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
- Adelaide Institute for Sleep Health and Flinders Health and Medical Research InstituteFlinders UniversityAdelaideAustralia
| | - Jane E. Butler
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
- Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
| | - Lynne E. Bilston
- Neuroscience Research AustraliaSydneyNew South WalesAustralia
- Faculty of Medicine and HealthUniversity of New South WalesSydneyNew South WalesAustralia
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Tatkov S, Rees M, Gulley A, van den Heuij LGT, Nilius G. Asymmetrical nasal high flow ventilation improves clearance of CO 2 from the anatomical dead space and increases positive airway pressure. J Appl Physiol (1985) 2023; 134:365-377. [PMID: 36633864 PMCID: PMC9886347 DOI: 10.1152/japplphysiol.00692.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Positive airway pressure that dynamically changes with breathing, and clearance of anatomical dead space are the key mechanisms of noninvasive respiratory support with nasal high flow (NHF). Pressure mainly depends on flow rate and nare occlusion. The hypothesis is that an increase in asymmetrical occlusion of the nares leads to an improvement in dead-space clearance resulting in a reduction in re-breathing. Clearance was investigated with volumetric capnography in an adult upper-airway model, which was ventilated by a lung simulator with entrained carbon dioxide (CO2) at respiratory rates (RR) of 15-45 min-1 and at 18 min-1 with chronic obstructive pulmonary disease (COPD) breathing patterns. Clearance was assessed at NHF of 20-60 L/min with a symmetrical interface (SI) and an asymmetrical interface (AI). CO2 kinetics visualized by infrared spectroscopy and mathematical modeling were used to study the mechanisms of clearance. At a higher RR (35 min-1) and NHF of 60 L/min, clearance in the upper airway was significantly higher with the AI when compared with the SI (29.64 ± 9.96%, P < 0.001), as opposed to at a lower RR (15 min-1) (1.40 ± 6.25%, P > 0.05), (means ± SD). With COPD breathing, clearance by NHF was reduced but significantly improved with the AI by 45.93% relative to the SI at NHF 20 L/min (P < 0.0001). The maximum pressure achieved with the AI was 6.6 cmH2O and NHF was 60 L/min at the end of expiration. Pressure differences between nasal cavities led to the reverse flow observed in the optical model. Asymmetrical NHF increases dead-space clearance by reverse flow through the choanae and accelerates purging of expired gas via the less occluded nare.NEW & NOTEWORTHY The asymmetrical interface generated reverse flow in the nasal cavities and across the choana, which led to unidirectional purging of expired gas from the upper airways. This accelerated the clearance of anatomical dead space and reduced re-breathing while increased resistance to flow resulted in higher positive end-expiratory pressure (PEEP). These findings are relevant to patients with elevated respiratory rates or with expiratory flow limitations where dead-space clearance by NHF can be substantially reduced.
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Affiliation(s)
| | - Monique Rees
- 1Fisher & Paykel Healthcare Ltd., Auckland, New Zealand
| | - Anton Gulley
- 1Fisher & Paykel Healthcare Ltd., Auckland, New Zealand
| | | | - Georg Nilius
- 2Evang. Kliniken Essen-Mitte GmbH, Essen, Germany,3Universität Witten/Herdecke, Witten, Germany
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A review of upper airway physiology relevant to the delivery and deposition of inhalation aerosols. Adv Drug Deliv Rev 2022; 191:114530. [PMID: 36152685 DOI: 10.1016/j.addr.2022.114530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 08/07/2022] [Accepted: 09/01/2022] [Indexed: 01/24/2023]
Abstract
Developing effective oral inhaled drug delivery treatment strategies for respiratory diseases necessitates a thorough knowledge of the respiratory system physiology, such as the differences in the airway channel's structure and geometry in health and diseases, their surface properties, and mechanisms that maintain their patency. While respiratory diseases, such as chronic obstructive pulmonary disease (COPD) and asthma and their implications on the lower airways have been the core focus of most of the current research, the role of the upper airway in these diseases is less known, especially in the context of inhaled drug delivery. This is despite the fact that the upper airway is the passageway for inhaled drugs to be delivered to the lower airways, and their replicas are indispensable in current standards, such as the cascade impactor experiments for testing inhaled drug delivery technology. This review provides an overview of upper airway collapsibility and their mechanical properties, the effects of age and gender on upper airway geometry, and surface properties. The review also discusses how COPD and asthma affect the upper airway and the typical inhalation flow characteristics exhibited by the patients with these diseases.
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McCartney A, Phillips D, James M, Chan O, Neder JA, de-Torres JP, Domnik NJ, Crinion SJ. Ventilatory neural drive in chronically hypercapnic patients with COPD: effects of sleep and nocturnal noninvasive ventilation. Eur Respir Rev 2022; 31:31/165/220069. [PMID: 36130786 DOI: 10.1183/16000617.0069-2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 06/29/2022] [Indexed: 11/05/2022] Open
Abstract
Sleep brings major challenges for the control of ventilation in humans, particularly the regulation of arterial carbon dioxide pressure (P aCO2 ). In patients with COPD, chronic hypercapnia is associated with increased mortality. Therefore, nocturnal high-level noninvasive positive-pressure ventilation (NIV) is recommended with the intention to reduce P aCO2 down to normocapnia. However, the long-term physiological consequences of P aCO2 "correction" on the mechanics of breathing, gas exchange efficiency and resulting symptoms (i.e. dyspnoea) remain poorly understood. Investigating the influence of sleep on the neural drive to breathe and its translation to the mechanical act of breathing is of foremost relevance to create a solid rationale for the use of nocturnal NIV. In this review, we critically discuss the mechanisms by which sleep influences ventilatory neural drive and mechanical consequences in healthy subjects and hypercapnic patients with advanced COPD. We then discuss the available literature on the effects of nocturnal NIV on ventilatory neural drive and respiratory mechanics, highlighting open avenues for further investigation.
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Affiliation(s)
| | - Devin Phillips
- Dept of Medicine, Queen's University, Kingston, ON, Canada
| | - Matthew James
- Dept of Medicine, Queen's University, Kingston, ON, Canada
| | - Olivia Chan
- Dept of Medicine, Queen's University, Kingston, ON, Canada
| | - J Alberto Neder
- Dept of Medicine, Queen's University, Kingston, ON, Canada.,Division of Respirology and Sleep Medicine, Kingston Health Sciences Centre, Kingston, ON, Canada
| | - Juan P de-Torres
- Dept of Medicine, Queen's University, Kingston, ON, Canada.,Division of Respirology and Sleep Medicine, Kingston Health Sciences Centre, Kingston, ON, Canada
| | - Nicolle J Domnik
- Dept of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Sophie J Crinion
- Dept of Medicine, Queen's University, Kingston, ON, Canada .,Division of Respirology and Sleep Medicine, Kingston Health Sciences Centre, Kingston, ON, Canada
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Lin S, Premaraj TS, Gamage PT, Dong P, Premaraj S, Gu L. Upper Airway Flow Dynamics in Obstructive Sleep Apnea Patients with Various Apnea-Hypopnea Index. Life (Basel) 2022; 12:1080. [PMID: 35888168 PMCID: PMC9318930 DOI: 10.3390/life12071080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 07/03/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023] Open
Abstract
BACKGROUND AND AIM This study evaluates the upper airway flow characteristics, anatomical features and analyzes their correlations with AHI in patients with varied degrees of OSA severity seeking for discernments of the underlying pathophysiological profile. MATERIALS AND METHODS Patient-specific computational fluid dynamics models were reconstructed from high-resolution cone-beam computed tomography images for 4 OSA patients classified as minimal, mild, moderate, and severe according to AHI. RESULTS The parameters, minimal cross-sectional area (MCA), and the pharyngeal airway volume did not show clear correlations with the OSA severity defined according to AHI. No correlations were found between the classically defined resistance of the airway in terms of pressure drop and AHI. The flow analysis further showed that the fluid mechanisms likely to cause airway collapse are associated with the degree of narrowing in the pharyngeal airway rather than AHI. Results also suggested that some patients classified as severe OSA according to the AHI can show less susceptibility to airway collapse than patients with relatively lower AHI values and vice versa. CONCLUSIONS The relative contribution of anatomical and non-anatomical causes to the OSA severity can significantly vary between patients. AHI alone is inadequate to be used as a marker of the pathophysiological profile of OSA. Combining airflow analysis with AHI in diagnosing OSA severity may provide additional details about the underlying pathophysiology, subsequently improving the individualized clinical outcomes.
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Affiliation(s)
- Shengmao Lin
- School of Civil Engineering and Architecture, Xiamen University of Technology, Xiamen 361024, China;
| | | | - Peshala T. Gamage
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA;
| | - Pengfei Dong
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA;
| | - Sundaralingam Premaraj
- College of Dental Medicine, Nova Southeastern University, Fort Lauderdale, FL 33328, USA; (T.S.P.); (S.P.)
| | - Linxia Gu
- Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA;
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8
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Effects of respiratory rate on the fluid mechanics of a reconstructed upper airway. Med Eng Phys 2022; 100:103746. [DOI: 10.1016/j.medengphy.2021.103746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 11/25/2021] [Accepted: 12/21/2021] [Indexed: 11/19/2022]
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9
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Gallagher C, Jalalifar S, Salehi F, Kourmatzis A, Cheng S. A two-fluid model for powder fluidisation in turbulent channel flows. POWDER TECHNOL 2021. [DOI: 10.1016/j.powtec.2021.05.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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Jugé L, Yeung J, Knapman FL, Burke PGR, Lowth AB, Gan KZC, Brown EC, Butler JE, Eckert DJ, Ngiam J, Sutherland K, Cistulli PA, Bilston LE. Influence of mandibular advancement on tongue dilatory movement during wakefulness and how this is related to oral appliance therapy outcome for obstructive sleep apnea. Sleep 2021; 44:5909314. [PMID: 32954420 DOI: 10.1093/sleep/zsaa196] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 07/19/2020] [Indexed: 01/17/2023] Open
Abstract
STUDY OBJECTIVES To characterize how mandibular advancement splint (MAS) alters inspiratory tongue movement in people with obstructive sleep apnea (OSA) during wakefulness and whether this is associated with MAS treatment outcome. METHODS A total of 87 untreated OSA participants (20 women, apnea-hypopnea index (AHI) 7-102 events/h, aged 19-76 years) underwent a 3T MRI with a MAS in situ. Mid-sagittal tagged images quantified inspiratory tongue movement with the mandible in a neutral position and advanced to 70% of the maximum. Movement was quantified with harmonic phase methods. Treatment outcome was determined after at least 9 weeks of therapy. RESULTS A total of 72 participants completed the study: 34 were responders (AHI < 5 or AHI ≤ 10events/h with >50% reduction in AHI), 9 were partial responders (>50% reduction in AHI but AHI > 10 events/h), and 29 nonresponders (change in AHI <50% and AHI ≥ 10 events/h). About 62% (45/72) of participants had minimal inspiratory tongue movement (<1 mm) in the neutral position, and this increased to 72% (52/72) after advancing the mandible. Mandibular advancement altered inspiratory tongue movement pattern for 40% (29/72) of participants. When tongue dilatory patterns altered with advancement, 80% (4/5) of those who changed to a counterproductive movement pattern (posterior movement >1 mm) were nonresponders and 71% (5/7) of those who changed to beneficial (anterior movement >1 mm) were partial or complete responders. CONCLUSIONS The mandibular advancement action on upper airway dilator muscles differs between individuals. When mandibular advancement alters inspiratory tongue movement, therapeutic response to MAS therapy was more common among those who convert to a beneficial movement pattern.
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Affiliation(s)
- Lauriane Jugé
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Jade Yeung
- Neuroscience Research Australia, Sydney, New South Wales, Australia
| | - Fiona L Knapman
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Peter G R Burke
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Aimee B Lowth
- Respiratory and Sleep Medicine Department, Royal North Shore Hospital, Sydney, New South Wales, Australia
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia
| | - Ken Z C Gan
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Elizabeth C Brown
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- Respiratory and Sleep Medicine Department, Prince of Wales Hospital, Sydney, New South Wales, Australia
| | - Jane E Butler
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Danny J Eckert
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
- Adelaide Institute for Sleep Health, Flinders University, Adelaide, South Australia, Australia
| | - Joachim Ngiam
- Respiratory and Sleep Medicine Department, Royal North Shore Hospital, Sydney, New South Wales, Australia
| | - Kate Sutherland
- Respiratory and Sleep Medicine Department, Royal North Shore Hospital, Sydney, New South Wales, Australia
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia
| | - Peter A Cistulli
- Respiratory and Sleep Medicine Department, Royal North Shore Hospital, Sydney, New South Wales, Australia
- Charles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia
| | - Lynne E Bilston
- Neuroscience Research Australia, Sydney, New South Wales, Australia
- Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
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Dergacheva O, Fleury-Curado T, Polotsky VY, Kay M, Jain V, Mendelowitz D. GABA and glycine neurons from the ventral medullary region inhibit hypoglossal motoneurons. Sleep 2021; 43:5674942. [PMID: 31832664 DOI: 10.1093/sleep/zsz301] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 10/25/2019] [Indexed: 12/17/2022] Open
Abstract
Obstructive sleep apnea (OSA) is a common disorder characterized by repetitive sleep-related losses of upper airway patency that occur most frequently during rapid eye movement (REM) sleep. Hypoglossal motoneurons play a key role in regulating upper airway muscle tone and patency during sleep. REM sleep activates GABA and glycine neurons in the ventral medulla (VM) to induce cortical desynchronization and skeletal muscle atonia during REM sleep; however, the role of this brain region in modulating hypoglossal motor activity is unknown. We combined optogenetic and chemogenetic approaches with in-vitro and in-vivo electrophysiology, respectfully, in GAD2-Cre mice of both sexes to test the hypothesis that VM GABA/glycine neurons control the activity of hypoglossal motoneurons and tongue muscles. Here, we show that there is a pathway originating from GABA/glycine neurons in the VM that monosynaptically inhibits brainstem hypoglossal motoneurons innervating both tongue protruder genioglossus (GMNs) and retractor (RMNs) muscles. Optogenetic activation of ChR2-expressing fibers induced a greater postsynaptic inhibition in RMNs than in GMNs. In-vivo chemogenetic activation of VM GABA/glycine neurons produced an inhibitory effect on tongue electromyographic (EMG) activity, decreasing both the amplitude and duration of inspiratory-related EMG bursts without any change in respiratory rate. These results indicate that activation of GABA/glycine neurons from the VM inhibits tongue muscles via a direct pathway to both GMNs and RMNs. This inhibition may play a role in REM sleep associated upper airway obstructions that occur in patients with OSA.
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Affiliation(s)
- Olga Dergacheva
- Department of Pharmacology and Physiology, the George Washington University, Washington, DC
| | - Thomaz Fleury-Curado
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Vsevolod Y Polotsky
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Matthew Kay
- Department of Biomedical Engineering, the George Washington University, Washington, DC
| | - Vivek Jain
- Department of Medicine, the George Washington University, Washington, DC
| | - David Mendelowitz
- Department of Pharmacology and Physiology, the George Washington University, Washington, DC
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12
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Barkmeier-Kraemer JM. Isolated Voice Tremor: A Clinical Variant of Essential Tremor or a Distinct Clinical Phenotype? Tremor Other Hyperkinet Mov (N Y) 2020; 10:tre-10-738. [PMID: 32015933 PMCID: PMC6988183 DOI: 10.7916/tohm.v0.738] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 11/26/2019] [Indexed: 12/01/2022] Open
Abstract
Background The consensus statement by the Task Force on Tremor of the International Parkinson and Movement Disorder Society excludes individuals with "isolated voice tremor" as a clinical variant of essential tremor (ET). This clinical viewpoint presents a rationale for reconsideration of "isolated voice tremor" as a clinical variant of ET. Methods Evidence from the literature was extracted to characterize the clinical phenotype of "isolated voice tremor," or essential vocal tremor (EVT). Clinical features were extracted from relevant literature available at pubmed.gov using the terms "EVT," "essential voice tremor," "primary voice tremor," and "organic voice tremor." Results The average age of onset in those with EVT was older than 60 years (range 19-84 years), with 75-93% being female. The typical duration of vocal tremor ranged from 1 to 13 years (average 6 years). The distribution of structures exhibiting tremor included the larynx, soft palate, pharynx, and base of tongue in the majority of patients, with some exhibiting tremor of the head and respiratory musculature. The condition of tremor occurred during speech and quiet respiration in 74% of individuals. Rate of tremor ranged from 4 to 10 Hz. Nearly 70% reported onset of vocal tremor prior to upper limb involvement. Family history of tremor was reported in 38-42% of individuals. Discussion Those previously classified with EVT demonstrate a similar familial history, rate, tremor classification, and body distribution of ET. EVT is proposed as a clinical variant of ET in the pattern of onset and progression of body distribution from the midline cranial to spinal neural pathways.
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13
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Ruehland WR, Rochford PD, Pierce RJ, Trinder J, Jordan AS, Cori JM, O'Donoghue FJ. Genioglossus muscle responses to resistive loads in severe OSA patients and healthy control subjects. J Appl Physiol (1985) 2019; 127:1586-1598. [PMID: 31647723 DOI: 10.1152/japplphysiol.00186.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study aimed to determine whether there is impairment of genioglossus neuromuscular responses to small negative pressure respiratory stimuli, close to the conscious detection threshold, in obstructive sleep apnea (OSA). We compared genioglossus electromyogram (EMGgg) responses to midinspiratory resistive loads of varying intensity (≈1.2-6.2 cmH2O·L-1·s), delivered via a nasal mask, between 16 severe OSA and 17 control participants while the subjects were awake and in a seated upright position. We examined the relationship between stimulus intensity and peak EMGgg amplitude in a 200-ms poststimulus window and hypothesized that OSA patients would have an increased activation threshold and reduced sensitivity in the relationship between EMGgg activation and stimulus intensity. There was no significant difference between control and OSA participants in the threshold (P = 0.545) or the sensitivity (P = 0.482) of the EMGgg amplitude vs. stimulus intensity relationship, where change in epiglottic pressure relative to background epiglottic pressure represented stimulus intensity. These results do not support the hypothesis that deficits in neuromuscular response to negative upper airway pressure exist in OSA during wakefulness; however, the results are likely influenced by a counterintuitive and novel genioglossus muscle suppression response observed in a significant proportion of both OSA and healthy control participants. This suppression response may relate to the inhibition seen in inspiratory muscles such as the diaphragm in response to sudden-onset negative pressure, and its presence provides new insight into the upper airway neuromuscular response to the collapsing force of negative pressure.NEW & NOTEWORTHY Our study used a novel midinspiratory resistive load stimulus to study upper airway neuromuscular responses to negative pressure during wakefulness in obstructive sleep apnea (OSA). Although no differences were found between OSA and healthy groups, the study uncovered a novel and unexpected suppression of neuromuscular activity in a large proportion of both OSA and healthy participants. The unusual response provides new insight into the upper airway neuromuscular response to the collapsing force of negative pressure.
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Affiliation(s)
- Warren R Ruehland
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Medicine (Austin Health), University of Melbourne, Heidelberg, Victoria, Australia
| | - Peter D Rochford
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Robert J Pierce
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Medicine (Austin Health), University of Melbourne, Heidelberg, Victoria, Australia
| | - John Trinder
- School of Psychological Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Amy S Jordan
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,School of Psychological Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Jennifer M Cori
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia
| | - Fergal J O'Donoghue
- Institute for Breathing and Sleep, Austin Health, Heidelberg, Victoria, Australia.,Department of Medicine (Austin Health), University of Melbourne, Heidelberg, Victoria, Australia
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14
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Zhao Y, Raco J, Kourmatzis A, Diasinos S, Chan HK, Yang R, Cheng S. The effects of upper airway tissue motion on airflow dynamics. J Biomech 2019; 99:109506. [PMID: 31780123 DOI: 10.1016/j.jbiomech.2019.109506] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/08/2019] [Accepted: 11/11/2019] [Indexed: 02/02/2023]
Abstract
The human upper airway is not only geometrically complex, but it can also deform dynamically as a result of active muscle contraction and motility during respiration. How the active transformation of the airway geometry affects airflow dynamics during respiration is not well understood despite the importance of this knowledge towards improving current understanding of particle transport and deposition. In this study, particle imaging velocimetry (PIV) measurements of the fluid dynamics are presented in a physiologically realistic human upper airway replica for (i) the undeformed case and (ii) the case where realistic soft tissue motion during breathing is emulated. Results from this study show that extrathoracic wall motion alters the flow field significantly such that the fluid dynamics is distinctly different from the undeformed airway. Distinctive flow field patterns in the physiologically realistic airway include (i) fluid recirculation at the back of the tongue and cranial to the tip of the epiglottis during mid-inspiration, (ii) horizontal and posteriorly directed flow at the back of tongue at the peak of inspiration and (iii) a more homogeneous flow across the airway downstream from the epiglottis. These findings suggest that the active deformation of the human upper airway may potentially influence particle transport and deposition at the back of the tongue and therefore, highlights the importance of considering extrathoracic wall motion in future airway flow studies. D.
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Affiliation(s)
- Yongling Zhao
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006, Australia; Department of Mechanical and Process Engineering, ETH Zürich, Zürich 8093, Switzerland
| | - Joel Raco
- School of Engineering, Macquarie University, NSW 2109, Australia
| | - Agisilaos Kourmatzis
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW 2006, Australia
| | - Sammy Diasinos
- School of Engineering, Macquarie University, NSW 2109, Australia
| | - Hak-Kim Chan
- Advanced Drug Delivery Group, School of Pharmacy, The University of Sydney, NSW 2006, Australia
| | - Runyu Yang
- School of Materials Science and Engineering, UNSW Sydney, NSW 2052, Australia
| | - Shaokoon Cheng
- School of Engineering, Macquarie University, NSW 2109, Australia.
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15
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Lun HM, Zhu SY, Hu Q, Liu YL, Wei LS. Sonographic Assessment of Oropharynx Movement During Deep Breathing. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:2906-2914. [PMID: 31474385 DOI: 10.1016/j.ultrasmedbio.2019.07.680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 06/10/2019] [Accepted: 07/29/2019] [Indexed: 06/10/2023]
Abstract
To investigate the feasibility of ultrasonography in detecting the oropharynx movement during deep breathing and to quantitatively analyze oropharynx airway lumen changes during deep breathing. The motions of oropharynx were monitored, and sonographic measurements of airway lumen were obtained during deep breathing in 448 healthy volunteers. Adequate visualization of oropharynx movement was obtained on all healthy volunteers. The anterior-posterior (AP) diameters and AP/transverse (T) diameter ratios were greater at the end of deep inspiration than that at the end of deep expiration for each sex (p < 0.01). The anterior-posterior dimensional changes were greater than lateral airway dimensional changes each sex (p < 0.05). Ultrasonography could provide realistic impression of the process on the oropharynx movement during deep breathing and perform the quantitative analysis of the oropharynx airway lumen changes during deep breathing. The results were encouraging and supported the utility of ultrasonography in future studies.
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Affiliation(s)
- Hai-Mei Lun
- Department of Diagnostic Ultrasound, People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Shang-Yong Zhu
- Department of Diagnostic Ultrasound, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China.
| | - Qiao Hu
- Department of Diagnostic Ultrasound, People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
| | - Yao-Li Liu
- Department of Diagnostic Ultrasound, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi, China
| | - Li-Si Wei
- Department of Diagnostic Ultrasound, People's Hospital of Guangxi Zhuang Autonomous Region, Nanning, China
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16
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Bates AJ, Schuh A, Amine-Eddine G, McConnell K, Loew W, Fleck RJ, Woods JC, Dumoulin CL, Amin RS. Assessing the relationship between movement and airflow in the upper airway using computational fluid dynamics with motion determined from magnetic resonance imaging. Clin Biomech (Bristol, Avon) 2019; 66:88-96. [PMID: 29079097 DOI: 10.1016/j.clinbiomech.2017.10.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/05/2017] [Accepted: 10/10/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND Computational fluid dynamics simulations of respiratory airflow in the upper airway reveal clinically relevant information, including sites of local resistance, inhaled particle deposition, and the effect of pathological constrictions. Unlike previous simulations, which have been performed on rigid anatomical models from static medical imaging, this work utilises ciné imaging during respiration to create dynamic models and more closely represent airway physiology. METHODS Airway movement maps were obtained from non-rigid image registration of fast-cine MRI and applied to high-spatial-resolution airway surface models. Breathing flowrates were recorded simultaneously with imaging. These data formed the boundary conditions for large eddy simulation computations of the airflow from exterior mask to bronchi. Simulations with rigid geometries were performed to demonstrate the resulting airflow differences between airflow simulations in rigid and dynamic airways. FINDINGS In the analysed rapid breathing manoeuvre, incorporating airway movement significantly changed the findings of the CFD simulations. Peak resistance increased by 19.8% and occurred earlier in the breath. Overall pressure loss decreased by 19.2%, and the proportion of flow in the mouth increased by 13.0%. Airway wall motion was out-of-phase with the air pressure force, demonstrating the presence of neuromuscular motion. In total, the anatomy did 25.2% more work on the air than vice versa. INTERPRETATIONS Realistic movement of the airway is incorporated into CFD simulations of airflow in the upper airway for the first time. This motion is vital to producing clinically relevant computational models of respiratory airflow and will allow novel analysis of dynamic conditions, such as sleep apnoea.
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Affiliation(s)
- Alister J Bates
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Bioengineering, Imperial College London, UK.
| | - Andreas Schuh
- Department of Computing, Imperial College London, UK
| | | | - Keith McConnell
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Wolfgang Loew
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Robert J Fleck
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Jason C Woods
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Charles L Dumoulin
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Raouf S Amin
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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17
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Kwan BCH, Jugé L, Gandevia SC, Bilston LE. Sagittal Measurement of Tongue Movement During Respiration: Comparison Between Ultrasonography and Magnetic Resonance Imaging. ULTRASOUND IN MEDICINE & BIOLOGY 2019; 45:921-934. [PMID: 30691918 DOI: 10.1016/j.ultrasmedbio.2018.12.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2018] [Revised: 12/06/2018] [Accepted: 12/08/2018] [Indexed: 06/09/2023]
Abstract
The tongue makes up the anterior pharyngeal wall and is critical for airway patency. Magnetic resonance imaging (MRI) is commonly used to study pharyngeal muscle function in pharyngeal disorders such as obstructive sleep apnoea. Tagged MRI and ultrasound studies have separately revealed ∼1 mm of anterior tongue movement during inspiration in healthy patients, but these modalities have not been directly compared. In the study described here, agreement between ultrasound and MRI in measuring regional tongue displacement in 21 healthy patients and 21 patients with obstructive sleep apnoea was evaluated. We found good consistency and agreement between the two techniques, with an intra-class correlation coefficient of 0.79 (95% confidence interval: 0.75-0.82) for anteroposterior tongue motion during inspiration. Ultrasound measurements of posterior tongue displacement were 0.24 ± 0.64 mm greater than MRI measurements (95% limits of agreement: 1.03 to -1.49). This may reflect the higher spatial and temporal resolution of the ultrasound technique. This study confirms that ultrasound is a suitable method for quantifying inspiratory tongue movement.
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Affiliation(s)
- Benjamin C H Kwan
- Neuroscience Research Australia, Sydney, New South Wales, Australia; Prince of Wales Hospital Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia.
| | - Lauriane Jugé
- Neuroscience Research Australia, Sydney, New South Wales, Australia; School of Medical Sciences, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia, Sydney, New South Wales, Australia; Prince of Wales Hospital Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
| | - Lynne E Bilston
- Neuroscience Research Australia, Sydney, New South Wales, Australia; Prince of Wales Hospital Clinical School, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
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18
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Bates AJ, Schuh A, McConnell K, Williams BM, Lanier JM, Willmering MM, Woods JC, Fleck RJ, Dumoulin CL, Amin RS. A novel method to generate dynamic boundary conditions for airway CFD by mapping upper airway movement with non-rigid registration of dynamic and static MRI. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e3144. [PMID: 30133165 DOI: 10.1002/cnm.3144] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 06/21/2018] [Accepted: 08/12/2018] [Indexed: 06/08/2023]
Abstract
Computational fluid dynamics (CFD) simulations of airflow in the human airways have the potential to provide a great deal of information that can aid clinicians in case management and surgical decision making, such as airway resistance, energy expenditure, airflow distribution, heat and moisture transfer, and particle deposition, as well as the change in each of these due to surgical interventions. However, the clinical relevance of CFD simulations has been limited to date, as previous models either did not incorporate neuromuscular motion or any motion at all. Many common airway pathologies, such as obstructive sleep apnea (OSA) and tracheomalacia, involve large movements of the structures surrounding the airway, such as the tongue and soft palate. Airway wall motion may be due to many factors including neuromuscular motion, internal aerodynamic forces, and external forces such as gravity. Therefore, to realistically model these airway diseases, a method is required to derive the airway wall motion, whatever the cause, and apply it as a boundary condition to CFD simulations. This paper presents and validates a novel method of capturing in vivo motion of airway walls from magnetic resonance images with high spatiotemporal resolution, through a novel combination of non-rigid image, surface, and surface-normal-vector registration. Coupled with image-synchronous pneumotachography, this technique provides the necessary boundary conditions for dynamic CFD simulations of breathing, allowing the effect of the airway's complex motion to be calculated for the first time, in both normal subjects and those with conditions such as OSA.
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Affiliation(s)
- Alister J Bates
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Bioengineering, Imperial College London, UK
| | - Andreas Schuh
- Department of Computing, Imperial College London, UK
| | - Keith McConnell
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Brynne M Williams
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - J Matthew Lanier
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Matthew M Willmering
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Jason C Woods
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
- Departments of Radiology and Physics, University of Cincinnati, Cincinnati, OH, USA
| | - Robert J Fleck
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Radiology, University of Cincinnati, Cincinnati, OH, USA
| | - Charles L Dumoulin
- Imaging Research Center, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
| | - Raouf S Amin
- Division of Pulmonary Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati, Cincinnati, OH, USA
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19
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Ichikawa T, Yokoba M, Kimura M, Shibuya M, Easton PA, Katagiri M. Genioglossus muscle activity during sniff and reverse sniff in healthy men. Exp Physiol 2018; 103:1656-1665. [PMID: 30242925 DOI: 10.1113/ep086995] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 09/20/2018] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Maximal sniff nasal inspiratory and reverse sniff nasal expiratory pressures are measured as inspiratory and expiratory muscle strength, respectively. Is the genioglossus muscle activated during short maximal inspiratory and expiratory efforts through the nose? What is the main finding and its importance? Genioglossus muscle activity occurred with inspiratory muscle activity during a maximal sniff and with expiratory muscle activity during a maximal reverse sniff. These results indicate that genioglossus muscle activity is closely related to the generation of maximal sniff nasal inspiratory and reverse sniff nasal expiratory pressures. ABSTRACT Maximal sniff nasal inspiratory pressure (SNIPmax ) is widely used to assess inspiratory muscle strength. The sniff nasal inspiratory pressure (SNIP) is lower in patients with neuromuscular disease with bulbar involvement compared with those without, possibly owing to impaired upper airway muscle function. However, the degree to which the genioglossus (GG) muscle, one of the upper airway muscles, is activated during inspiratory and expiratory efforts through the nose remains unclear. Therefore, we examined GG activity during short and sharp inspiratory and expiratory efforts through the nose, i.e. sniff and reverse sniff manoeuvres. In eight normal young subjects, we inserted fine wire electrodes into the GG muscle, parasternal intercostal and scalene (inspiratory) muscles and transversus abdominis (expiratory) muscle. We assessed EMG activity of each muscle and measured SNIP and reverse sniff nasal expiratory pressure (RSNEP) during sniffs and reverse sniffs from low to high intensities in the sitting position. The highest SNIP and RSNEP were analysed as SNIPmax and maximal RSNEP (RSNEPmax ), respectively. In each subject, GG EMG activity increased linearly with increasing SNIP and RSNEP. The SNIPmax and RSNEPmax were -85.1 ± 15.9 and 83.2 ± 24.2 cmH2 O, respectively. Genioglossus EMG activity varied with EMG activity of the parasternal intercostal and scalene muscles during generation of SNIPmax and with EMG activity of the transversus abdominis muscle during RSNEPmax . Genioglossus EMG activity during generation of SNIPmax was higher than during RSNEPmax (62.9 ± 31.1% EMG of SNIPmax , P = 0.012). These results suggested that GG activity was closely related to the generation of both SNIPmax and RSNEPmax .
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Affiliation(s)
- Tsuyoshi Ichikawa
- School of Allied Health Sciences, Kitasato University, Kanagawa, Japan.,Rehabilitation Centre, Tokai University Oiso Hospital, Kanagawa, Japan
| | - Masanori Yokoba
- School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
| | | | - Manaka Shibuya
- Graduate School of Medical Sciences, Kitasato University, Kanagawa, Japan
| | - Paul A Easton
- Department of Critical Care, University of Calgary, Calgary, Alberta, Canada
| | - Masato Katagiri
- School of Allied Health Sciences, Kitasato University, Kanagawa, Japan
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Cori JM, Nicholas CL, Avraam J, Lee VV, Schembri R, Jackson ML, Jordan AS. The Effects of Experimental Sleep Fragmentation and Sleep Deprivation on the Response of the Genioglossus Muscle to Inspiratory Resistive Loads. J Clin Sleep Med 2018; 14:715-724. [PMID: 29734983 DOI: 10.5664/jcsm.7090] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 12/13/2017] [Indexed: 11/13/2022]
Abstract
STUDY OBJECTIVES Poor upper airway dilator muscle function may contribute to obstructive sleep apnea (OSA). Sleep deprivation reduces dilator muscle responsiveness, but sleep fragmentation, which is most characteristic of OSA, has not been assessed. This study compared the effects of sleep deprivation and fragmentation on dilator muscle responsiveness during wakefulness. METHODS Twenty-four healthy individuals (10 female) participated in two consecutive overnight polysomnography (PSG) sessions. The first was an adaptation PSG of normal sleep. The second was an experimental PSG, where participants were allocated to groups of either normal sleep, no sleep, or fragmented sleep. Inspiratory resistive loading assessment occurred the morning following each PSG. Four 10 cmH2O and four 20 cmH2O loads were presented in random order for 60 seconds while participants were awake and supine. Sleep (electroencephalogram, electrooculogram, electromyogram [EMG]), intramuscular genioglossus activity (EMGGG), and ventilation were measured throughout the loading sessions. RESULTS Five controls, seven sleep deprivation participants, and seven sleep fragmentation participants provided data. Contrary to expectations, neither EMGGG nor ventilation showed significant interaction effects (group × session × load) during resistive loading. There was a main effect of load, with peak EMGGG (mean % max ± standard error) significantly higher for the 20 cmH2O load (4.1 ± 0.6) than the 10 cmH2O load (3.3 ± 0.6) across both sessions and all groups. Similar results were observed for peak inspiratory flow, duty cycle, and mask pressure. CONCLUSIONS Upper airway function was not affected by 1 night of no sleep or poor-quality sleep. This raises doubt as to whether fragmented sleep in OSA increases disorder severity via reduced upper airway dilator responses.
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Affiliation(s)
- Jennifer M Cori
- Institute for Breathing and Sleep and Austin Health, Heidelberg, Victoria, Australia
| | - Christian L Nicholas
- Institute for Breathing and Sleep and Austin Health, Heidelberg, Victoria, Australia.,Melbourne School of Psychological Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Joanne Avraam
- Institute for Breathing and Sleep and Austin Health, Heidelberg, Victoria, Australia.,Melbourne School of Psychological Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - V Vien Lee
- Institute for Breathing and Sleep and Austin Health, Heidelberg, Victoria, Australia.,School of Health & Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Rachel Schembri
- Institute for Breathing and Sleep and Austin Health, Heidelberg, Victoria, Australia.,School of Health & Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Melinda L Jackson
- Institute for Breathing and Sleep and Austin Health, Heidelberg, Victoria, Australia.,Melbourne School of Psychological Sciences, University of Melbourne, Parkville, Victoria, Australia.,School of Health & Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Amy S Jordan
- Institute for Breathing and Sleep and Austin Health, Heidelberg, Victoria, Australia.,Melbourne School of Psychological Sciences, University of Melbourne, Parkville, Victoria, Australia
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21
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Kwan BCH, McBain RA, Luu BL, Butler JE, Bilston LE, Gandevia SC. Influence of respiratory mechanics and drive on genioglossus movement under ultrasound imaging. PLoS One 2018; 13:e0195884. [PMID: 29659626 PMCID: PMC5901985 DOI: 10.1371/journal.pone.0195884] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 03/30/2018] [Indexed: 11/18/2022] Open
Abstract
METHODS Twenty healthy subjects (10 males, age 28±5 years [mean ± SD]) lay supine, awake, with the head in a neutral position. Ventilation was monitored with inductance bands. Real-time B-mode ultrasound movies were analysed. We measured genioglossus motion (i) during spontaneous breathing, voluntary targeted breathing (normal tidal volume Vt), and voluntary hyperpnoea (at 1.5Vt and 2 Vt); (ii) during inspiratory flow resistive loading; (iii) with changes in end-expiratory lung volume (EELV). RESULTS Average peak inspiratory displacement of the infero-posterior region of genioglossus was 0.89±0.56 mm; 1.02±0.88 mm; 1.27±0.70 mm respectively for voluntary Vt, and during voluntary hyperpnoea at 1.5Vt and 2Vt. A change in genioglossus motion was observed with increased Vt. During increasing inspiratory resistive loading, the genioglossus displaced less anteriorly (p = 0.005) but more inferiorly (p = 0.027). When lung volume was altered, no significant changes in genioglossus movement were observed (p = 0.115). CONCLUSION In healthy subjects, we observed non-uniform heterogeneous inspiratory motion within the inferoposterior part of genioglossus during spontaneous quiet breathing with mean peak displacement between 0.5-2 mm, with more displacement in the posterior region than the anterior. This regional heterogeneity disappeared during voluntary targeted breathing. This may be due to different neural drive to genioglossus during voluntary breathing. During inspiratory resistive loading, the observed genioglossus motion may serve to maintain upper airway patency by balancing intraluminal negative pressure with positive pressure generated by upper airway dilatory muscles. In contrast, changes in EELV were not accompanied by major changes in genioglossus motion.
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Affiliation(s)
- Benjamin C. H. Kwan
- Neuroscience Research Australia (NeuRA), Barker St, Sydney, NSW, Australia
- Prince of Wales Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
- * E-mail:
| | - Rachel A. McBain
- Neuroscience Research Australia (NeuRA), Barker St, Sydney, NSW, Australia
| | - Billy L. Luu
- Neuroscience Research Australia (NeuRA), Barker St, Sydney, NSW, Australia
| | - Jane E. Butler
- Neuroscience Research Australia (NeuRA), Barker St, Sydney, NSW, Australia
| | - Lynne E. Bilston
- Neuroscience Research Australia (NeuRA), Barker St, Sydney, NSW, Australia
- Prince of Wales Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Simon C. Gandevia
- Neuroscience Research Australia (NeuRA), Barker St, Sydney, NSW, Australia
- Prince of Wales Clinical School, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
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22
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Cori JM, O'Donoghue FJ, Jordan AS. Sleeping tongue: current perspectives of genioglossus control in healthy individuals and patients with obstructive sleep apnea. Nat Sci Sleep 2018; 10:169-179. [PMID: 29942169 PMCID: PMC6007201 DOI: 10.2147/nss.s143296] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The focus of this review was on the genioglossus (GG) muscle and its role in maintaining upper airway patency in both healthy individuals and obstructive sleep apnea (OSA) patients. This review provided an overview of GG anatomy and GG control and function during both wakefulness and sleep in healthy individuals and in those with OSA. We reviewed evidence for the role of the GG in OSA pathogenesis and also highlighted abnormalities in GG morphology, responsiveness, tissue movement patterns and neurogenic control that may contribute to or result from OSA. We summarized the different methods for improving GG function and/or activity in OSA and their efficacy. In addition, we discussed the possibility that assessing the synergistic activation of multiple upper airway dilator muscles may provide greater insight into upper airway function and OSA pathogenesis, rather than assessing the GG in isolation.
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Affiliation(s)
- Jennifer M Cori
- Department of Respiratory and Sleep Medicine, Institute for Breathing and Sleep, Austin Hospital, Heidelberg, VIC, Australia
| | - Fergal J O'Donoghue
- Department of Respiratory and Sleep Medicine, Institute for Breathing and Sleep, Austin Hospital, Heidelberg, VIC, Australia
| | - Amy S Jordan
- Department of Psychology, Melbourne School of Psychological Sciences, University of Melbourne, Parkville, VIC, Australia
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Kourmatzis A, Cheng S, Chan HK. Airway geometry, airway flow, and particle measurement methods: implications on pulmonary drug delivery. Expert Opin Drug Deliv 2017; 15:271-282. [DOI: 10.1080/17425247.2018.1406917] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- A. Kourmatzis
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, Australia
| | - S. Cheng
- Department of Engineering, Macquarie University, Sydney, Australia
| | - H.-K. Chan
- Advanced Drug Delivery Group, Faculty of Pharmacy, The University of Sydney, Sydney, Australia
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LaCross A, Watson PJ, Bailey EF. Association between Laryngeal Airway Aperture and the Discharge Rates of Genioglossus Motor Units. Front Physiol 2017; 8:27. [PMID: 28179887 PMCID: PMC5263150 DOI: 10.3389/fphys.2017.00027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 01/11/2017] [Indexed: 11/13/2022] Open
Abstract
We know very little about how muscles and motor units in one region of the upper airway are impacted by adjustments in an adjacent airway region. In this case, the focus is on regulation of the expiratory airstream by the larynx and how changes in laryngeal aperture impact muscle motor unit activities downstream in the pharynx. We selected sound production as a framework for study as it requires (i) sustained expiratory airflow, (ii) laryngeal airway regulation for production of whisper and voice, and (iii) pharyngeal airway regulation for production of different vowel sounds. We used these features as the means of manipulating expiratory airflow, pharyngeal, and laryngeal airway opening to compare the effect of each on the activation of genioglossus (GG) muscle motor units in the pharynx. We show that some GG muscle motor units (a) discharge stably on expiration associated with production of vowel sounds, (b) are exquisitely sensitive to subtle alterations in laryngeal airflow, and (c) discharge at higher firing rates in high flow vs. low flow conditions even when producing the same vowel sound. Our results reveal subtle changes in GG motor unit discharge rates that correlate with changes imposed at the larynx, and which may contribute to the regulation of the expiratory airstream.
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Affiliation(s)
- Amy LaCross
- Department of Physiology, College of Medicine, University of Arizona Tucson, AZ, USA
| | - Peter J Watson
- Department of Speech, Language, and Hearing Science, College of Liberal Arts, University of Minnesota Minneapolis, MN, USA
| | - E Fiona Bailey
- Department of Physiology, College of Medicine, University of Arizona Tucson, AZ, USA
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Cai M, Brown EC, Hatt A, Cheng S, Bilston LE. Effect of head and jaw position on respiratory-related motion of the genioglossus. J Appl Physiol (1985) 2016; 120:758-65. [DOI: 10.1152/japplphysiol.00382.2015] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 01/19/2016] [Indexed: 11/22/2022] Open
Abstract
Head and jaw position influence upper airway patency and electromyographic (EMG) activity of the main upper airway dilator muscle, the genioglossus. However, it is not known whether changes in genioglossus EMG activity translate into altered muscle movement during respiration. The aim of this study was to determine the influence of head and jaw position on dilatory motion of the genioglossus in healthy adult men during quiet breathing by measuring the displacement of the posterior tongue in six positions—neutral, head extension, head rotation, head flexion, mouth opening, and mandibular advancement. Respiratory-related motion of the genioglossus was imaged with spatial modulation of magnetization (SPAMM) in 12 awake male participants. Tissue displacement was quantified with harmonic phase (HARP) analysis. The genioglossus moved anteriorly beginning immediately before or during inspiration, and there was greater movement in the oropharynx than in the velopharynx in all positions. Anterior displacements of the oropharyngeal tongue varied between neutral head position (0.81 ± 0.41 mm), head flexion (0.62 ± 0.45 mm), extension (0.39 ± 0.19 mm), axial rotation (0.39 ± 0.2 mm), mouth open (1.24 ± 0.72 mm), and mandibular advancement (1.08 ± 0.65 mm). Anteroposterior displacement increased in the mouth-open position and decreased in the rotated position relative to cross-sectional area (CSA) ( P = 0.002 and 0.02, respectively), but CSA did not independently predict anteroposterior movement overall ( P = 0.057). The findings of this study suggest that head position influences airway dilation during inspiration and may contribute to variation in airway patency in different head positions.
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Affiliation(s)
- Mingshu Cai
- Neuroscience Research Australia and University of New South Wales, Sydney, Australia
| | - Elizabeth C. Brown
- Neuroscience Research Australia and University of New South Wales, Sydney, Australia
| | - Alice Hatt
- Neuroscience Research Australia and University of New South Wales, Sydney, Australia
| | - Shaokoon Cheng
- Neuroscience Research Australia and University of New South Wales, Sydney, Australia
| | - Lynne E. Bilston
- Neuroscience Research Australia and University of New South Wales, Sydney, Australia
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Saboisky JP, Butler JE, Luu BL, Gandevia SC. Neurogenic Changes in the Upper Airway of Obstructive Sleep Apnoea. Curr Neurol Neurosci Rep 2015; 15:12. [DOI: 10.1007/s11910-015-0537-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Cheng S, Brown EC, Hatt A, Butler JE, Gandevia SC, Bilston LE. Healthy humans with a narrow upper airway maintain patency during quiet breathing by dilating the airway during inspiration. J Physiol 2014; 592:4763-74. [PMID: 25217376 DOI: 10.1113/jphysiol.2014.279240] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
A patent upper airway is essential for survival. Increased age, obesity and some upper airway anatomical features are associated with failure to maintain upper airway patency during sleep, leading to obstructive sleep apnoea. However, many healthy subjects with these risk factors do not develop this condition. The aim of this study was to determine how anatomical factors and active dilator muscle contraction contribute to upper airway patency in healthy volunteers across a broad range of age and body mass index (BMI). A 'tagged' magnetic resonance imaging technique quantified respiratory-related motion of the anterior and lateral walls of the upper airway during quiet breathing in the supine position. Fifty-two subjects aged 22-68 years with BMI from 17.5 to 40.1 kg m(-2) were studied. Higher BMI was associated with smaller airway cross-sectional area at the level of soft palate (P < 0.05). The genioglossus moved anteriorly to dilate the upper airway during inspiration. This movement increased with increasing BMI, increasing age, a smaller airway area, and steeper tongue-base angle (all P < 0.05). Motion of the lateral upper airway at the soft-palate level was variable and less strongly linked to anatomical features of the upper airway. Multiple regression indicated that anterior genioglossus motion decreased with increasing airway area (P = 0.03) and with increasing tongue-base angle (P = 0.02). These data suggest that healthy humans, including those whose anatomy places them at increased risk of airway closure, can maintain upper airway patency by dynamically dilating the airway during inspiration.
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Affiliation(s)
- Shaokoon Cheng
- Neuroscience Research Australia, Sydney, Australia School of Medical Science, UNSW Medicine, Australia
| | | | - Alice Hatt
- Neuroscience Research Australia, Sydney, Australia
| | - Jane E Butler
- Neuroscience Research Australia, Sydney, Australia School of Medical Science, UNSW Medicine, Australia
| | - Simon C Gandevia
- Neuroscience Research Australia, Sydney, Australia Prince of Wales Clinical School, UNSW Medicine, Australia
| | - Lynne E Bilston
- Neuroscience Research Australia, Sydney, Australia Prince of Wales Clinical School, UNSW Medicine, Australia
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Kwan BCH, Butler JE, Hudson AL, McKenzie DK, Bilston LE, Gandevia SC. A novel ultrasound technique to measure genioglossus movement in vivo. J Appl Physiol (1985) 2014; 117:556-62. [DOI: 10.1152/japplphysiol.01257.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Upper airway muscles are important in maintaining airway patency. Visualization of their dynamic motion should allow measurement, comparison, and further understanding of their roles in healthy subjects and those with upper airway disorders. Currently, there are few clinically feasible real-time imaging methods. Methods such as tagged magnetic resonance imaging have documented movement of genioglossus (GG), the largest upper airway dilator. Inspiratory movement was largest in the posterior region of GG. This study aimed to develop a novel ultrasound (US) method to measure GG movement in real time. We tested 20 healthy, awake subjects (21–38 yr) breathing quietly in the supine posture with the head in a neutral position. US images were collected using a transducer positioned submentally. Image correlation analysis measured regional displacement of GG within a grid of points in the midsagittal plane throughout the respiratory cycle. Typically, motion began before inspiratory flow in an anteroinferior direction and peaked in midinspiration. Average peak displacements of the anterior, posterior, superior, and inferior grid points were 0.44 ± 0.23 (mean ± SD), 0.57 ± 0.35, 0.38 ± 0.20, and 0.62 ± 0.41 mm, respectively. Largest displacements occurred in the most inferoposterior part (0.70 ± 0.48 mm). This method had good intrarater repeatability within the same testing session, as well as across sessions. We have devised a simple noninvasive US method, which should be a useful tool to assess GG movement in normal subjects and those with sleep-disordered breathing.
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Affiliation(s)
- Benjamin C. H. Kwan
- Neuroscience Research Australia, Sydney, New South Wales, Australia; and
- University of New South Wales, Sydney, New South Wales, Australia
| | - Jane E. Butler
- Neuroscience Research Australia, Sydney, New South Wales, Australia; and
- University of New South Wales, Sydney, New South Wales, Australia
| | - Anna L. Hudson
- Neuroscience Research Australia, Sydney, New South Wales, Australia; and
- University of New South Wales, Sydney, New South Wales, Australia
| | - David K. McKenzie
- Neuroscience Research Australia, Sydney, New South Wales, Australia; and
- University of New South Wales, Sydney, New South Wales, Australia
| | - Lynne E. Bilston
- Neuroscience Research Australia, Sydney, New South Wales, Australia; and
- University of New South Wales, Sydney, New South Wales, Australia
| | - Simon C. Gandevia
- Neuroscience Research Australia, Sydney, New South Wales, Australia; and
- University of New South Wales, Sydney, New South Wales, Australia
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Amatoury J, Kairaitis K, Wheatley JR, Bilston LE, Amis TC. Peripharyngeal tissue deformation and stress distributions in response to caudal tracheal displacement: pivotal influence of the hyoid bone? J Appl Physiol (1985) 2014; 116:746-56. [DOI: 10.1152/japplphysiol.01245.2013] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Caudal tracheal displacement (TD) leads to improvements in upper airway (UA) function and decreased collapsibility. To better understand the mechanisms underlying these changes, we examined effects of TD on peripharyngeal tissue stress distributions [i.e., extraluminal tissue pressure (ETP)], deformation of its topographical surface (UA lumen geometry), and hyoid bone position. We studied 13 supine, anesthetized, tracheostomized, spontaneously breathing, adult male New Zealand white rabbits. Graded TD was applied to the cranial tracheal segment from 0 to ∼10 mm. ETP was measured at six locations distributed around/along the length of the UA, covering three regions: tongue, hyoid, and epiglottis. Axial images of the UA (nasal choanae to glottis) were acquired with computed tomography and used to measure lumen geometry (UA length; regional cross-sectional area) and hyoid bone displacement. TD resulted in nonuniform decreases in ETP (generally greatest at tongue region), ranging from −0.07 (−0.11 to −0.03) [linear mixed-effects model slope (95% confidence interval)] to −0.27 (−0.31 to −0.23) cmH2O/mm TD, across all sites. UA length increased by 1.6 (1.5–1.8)%/mm, accompanied by nonuniform increases in cross-sectional area (greatest at hyoid region) ranging from 2.8 (1.7–3.9) to 4.9 (3.8–6.0)%/mm. The hyoid bone was displaced caudally by 0.22 (0.18–0.25) mm/mm TD. In summary, TD imposes a load on the UA that results in heterogeneous changes in peripharyngeal tissue stress distributions and resultant lumen geometry. The hyoid bone may play a pivotal role in redistributing applied caudal tracheal loads, thus modifying tissue deformation distributions and determining resultant UA geometry outcomes.
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Affiliation(s)
- Jason Amatoury
- Ludwig Engel Centre for Respiratory Research, Westmead Millennium Institute, Westmead, New South Wales, Australia
- University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia; and
- Neuroscience Research Australia, Randwick, New South Wales, Australia
| | - Kristina Kairaitis
- Ludwig Engel Centre for Respiratory Research, Westmead Millennium Institute, Westmead, New South Wales, Australia
- University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia; and
| | - John R. Wheatley
- Ludwig Engel Centre for Respiratory Research, Westmead Millennium Institute, Westmead, New South Wales, Australia
- University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia; and
| | - Lynne E. Bilston
- Neuroscience Research Australia, Randwick, New South Wales, Australia
| | - Terence C. Amis
- Ludwig Engel Centre for Respiratory Research, Westmead Millennium Institute, Westmead, New South Wales, Australia
- University of Sydney at Westmead Hospital, Westmead, New South Wales, Australia; and
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Bilston LE, Gandevia SC. Biomechanical properties of the human upper airway and their effect on its behavior during breathing and in obstructive sleep apnea. J Appl Physiol (1985) 2014; 116:314-24. [DOI: 10.1152/japplphysiol.00539.2013] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The upper airway is a complex, multifunctional, dynamic neuromechanical system. Its patency during breathing requires moment-to-moment coordination of neural and mechanical behavior and varies with posture. Failure to continuously recruit and coordinate dilator muscles to counterbalance the forces that act to close the airway results in hypopneas or apneas. Repeated failures lead to obstructive sleep apnea (OSA). Obesity and anatomical variations, such as retrognathia, increase the likelihood of upper airway collapse by altering the passive mechanical behavior of the upper airway. This behavior depends on the mechanical properties of each upper airway tissue in isolation, their geometrical arrangements, and their physiological interactions. Recent measurements of respiratory-related deformation of the airway wall have shown that there are different patterns of airway soft tissue movement during the respiratory cycle. In OSA patients, airway dilation appears less coordinated compared with that in healthy subjects (matched for body mass index). Intrinsic mechanical properties of airway tissues are altered in OSA patients, but the factors underlying these changes have yet to be elucidated. How neural drive to the airway dilators relates to the biomechanical behavior of the upper airway (movement and stiffness) is still poorly understood. Recent studies have highlighted that the biomechanical behavior of the upper airway cannot be simply predicted from electromyographic activity (electromyogram) of its muscles.
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Affiliation(s)
- Lynne E. Bilston
- Neuroscience Research Australia and Prince of Wales Clinical School, University of New South Wales, New South Wales, Sydney, Australia
| | - Simon C. Gandevia
- Neuroscience Research Australia and Prince of Wales Clinical School, University of New South Wales, New South Wales, Sydney, Australia
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31
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Oppersma E, Doorduin J, van der Heijden EHFM, van der Hoeven JG, Heunks LMA. Noninvasive ventilation and the upper airway: should we pay more attention? CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2013; 17:245. [PMID: 24314000 PMCID: PMC4059377 DOI: 10.1186/cc13141] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In an effort to reduce the complications related to invasive ventilation, the use of noninvasive ventilation (NIV) has increased over the last years in patients with acute respiratory failure. However, failure rates for NIV remain high in specific patient categories. Several studies have identified factors that contribute to NIV failure, including low experience of the medical team and patient–ventilator asynchrony. An important difference between invasive ventilation and NIV is the role of the upper airway. During invasive ventilation the endotracheal tube bypasses the upper airway, but during NIV upper airway patency may play a role in the successful application of NIV. In response to positive pressure, upper airway patency may decrease and therefore impair minute ventilation. This paper aims to discuss the effect of positive pressure ventilation on upper airway patency and its possible clinical implications, and to stimulate research in this field.
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Horner RL. Neural control of the upper airway: integrative physiological mechanisms and relevance for sleep disordered breathing. Compr Physiol 2013; 2:479-535. [PMID: 23728986 DOI: 10.1002/cphy.c110023] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The various neural mechanisms affecting the control of the upper airway muscles are discussed in this review, with particular emphasis on structure-function relationships and integrative physiological motor-control processes. Particular foci of attention include the respiratory function of the upper airway muscles, and the various reflex mechanisms underlying their control, specifically the reflex responses to changes in airway pressure, reflexes from pulmonary receptors, chemoreceptor and baroreceptor reflexes, and postural effects on upper airway motor control. This article also addresses the determinants of upper airway collapsibility and the influence of neural drive to the upper airway muscles, and the influence of common drugs such as ethanol, sedative hypnotics, and opioids on upper airway motor control. In addition to an examination of these basic physiological mechanisms, consideration is given throughout this review as to how these mechanisms relate to integrative function in the intact normal upper airway in wakefulness and sleep, and how they may be involved in the pathogenesis of clinical problems such obstructive sleep apnea hypopnea.
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Brown EC, Cheng S, McKenzie DK, Butler JE, Gandevia SC, Bilston LE. Respiratory Movement of Upper Airway Tissue in Obstructive Sleep Apnea. Sleep 2013; 36:1069-1076. [PMID: 23814344 DOI: 10.5665/sleep.2812] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES To measure real-time movement of the tongue and lateral upper airway tissues in obstructive sleep apnea (OSA) subjects during wakefulness using tagged magnetic resonance imaging. DESIGN Comparison of the dynamic imaging of three groups of increasing severity OSA and a control group approximately matched for age and body mass index (BMI). SETTING Not-for-profit research institute. PARTICIPANTS 24 subjects (apnea hypopnea index [AHI] range 2-84 events/h, 6 with AHI < 5 events/h). METHODS The upper airway was imaged awake in two planes using SPAtial Modulation of Magnetization (SPAMM). Tissue displacements were quantified with harmonic phase analysis. MEASUREMENTS AND RESULTS All subjects had dynamic airway opening in the sagittal plane associated with inspiration. In the nasopharynx, the increase in airway cross-sectional area during inspiration correlated with minimal cross-sectional area of the airway (R = 0.900, P < 0.001). AHI correlated negatively with movement of the nasopharyngeal lateral walls (R = - 0.542, P = 0.006). Four movement patterns were observed during inspiration: "en bloc" anterior movement of the whole posterior tongue; movement of only the oropharyngeal posterior tongue; bidirectional movement; or minimal movement. Some subjects showed different inspiratory movement patterns with different breaths. A low AHI (< 5) was associated with en bloc movement (P = 0.002). CONCLUSIONS Inspiratory movement of the tongue varied between and within subjects, likely as a result of local and neural factors. However, in severe OSA inspiratory movement was minimal. CITATION Brown EC; Cheng S; McKenzie DK; Butler JE; Gandevia SC; Bilston LE. Respiratory movement of upper airway tissue in obstructive sleep apnea. SLEEP 2013;36(7):1069-1076.
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Brennick MJ. Understanding Airway Tissue Mechanics is a Step Towards Improving Treatments in OSA. Sleep 2013; 36:973-974. [PMID: 23814332 DOI: 10.5665/sleep.2788] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Affiliation(s)
- Michael J Brennick
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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Wagshul ME, Sin S, Lipton ML, Shifteh K, Arens R. Novel retrospective, respiratory-gating method enables 3D, high resolution, dynamic imaging of the upper airway during tidal breathing. Magn Reson Med 2013; 70:1580-90. [PMID: 23401041 DOI: 10.1002/mrm.24608] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 11/29/2012] [Accepted: 11/30/2012] [Indexed: 12/27/2022]
Abstract
PURPOSE A retrospective, respiratory-gated technique for measuring dynamic changes in the upper airway over the respiratory cycle was developed, with the ultimate goal of constructing anatomically and functionally accurate upper airway models in obstructive sleep apnea patients. METHODS Three-dimensional cine, retrospective respiratory-gated, gradient echo imaging was performed in six adolescents being evaluated for polycystic ovary syndrome, a disorder with a high obstructive sleep apnea prevalence. A novel retrospective gating scheme, synchronized to flow from a nasal cannula, limited image acquisition to predefined physiological ranges. Images were evaluated with respect to contrast, airway signal leakage, and demonstration of dynamic airway area changes. RESULTS Two patients were diagnosed with obstructive sleep apnea. Motion artifacts were absent in all image sets. Scan efficiency ranged from 48 to 88%. Soft tissue-to-airway contrast-to-noise ratio varied from 6.1 to 9.6. Airway signal leakage varied between 10 and 17% of soft tissue signal. Automated segmentation allowed calculation of airway area changes over the respiratory cycle. In one severe apnea patient, the technique allowed demonstration of asynchronous airway expansion and contraction above and below a severe constriction. CONCLUSIONS Retrospective, respiratory gated imaging of the upper airway has been demonstrated, utilizing a gating algorithm to ensure acquisition over specified ranges of respiratory rate and tidal volume.
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Affiliation(s)
- Mark E Wagshul
- Department of Radiology, Gruss MRRC, Albert Einstein College of Medicine, Bronx, New York, USA; Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York, USA
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Stavness I, Lloyd JE, Fels S. Automatic prediction of tongue muscle activations using a finite element model. J Biomech 2012; 45:2841-8. [PMID: 23021611 DOI: 10.1016/j.jbiomech.2012.08.031] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 08/20/2012] [Accepted: 08/22/2012] [Indexed: 11/29/2022]
Abstract
Computational modeling has improved our understanding of how muscle forces are coordinated to generate movement in musculoskeletal systems. Muscular-hydrostat systems, such as the human tongue, involve very different biomechanics than musculoskeletal systems, and modeling efforts to date have been limited by the high computational complexity of representing continuum-mechanics. In this study, we developed a computationally efficient tracking-based algorithm for prediction of muscle activations during dynamic 3D finite element simulations. The formulation uses a local quadratic-programming problem at each simulation time-step to find a set of muscle activations that generated target deformations and movements in finite element muscular-hydrostat models. We applied the technique to a 3D finite element tongue model for protrusive and bending movements. Predicted muscle activations were consistent with experimental recordings of tongue strain and electromyography. Upward tongue bending was achieved by recruitment of the superior longitudinal sheath muscle, which is consistent with muscular-hydrostat theory. Lateral tongue bending, however, required recruitment of contralateral transverse and vertical muscles in addition to the ipsilateral margins of the superior longitudinal muscle, which is a new proposition for tongue muscle coordination. Our simulation framework provides a new computational tool for systematic analysis of muscle forces in continuum-mechanics models that is complementary to experimental data and shows promise for eliciting a deeper understanding of human tongue function.
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Affiliation(s)
- Ian Stavness
- Department of Bioengineering, Clark Center, Room S221, Stanford University, Mail Code 5448, 318 Campus Drive, Stanford, CA 94305, USA.
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Zhu JH, Lee HP, Lim KM, Lee SJ, Teo LSL, Wang DY. Passive movement of human soft palate during respiration: A simulation of 3D fluid/structure interaction. J Biomech 2012; 45:1992-2000. [DOI: 10.1016/j.jbiomech.2012.04.027] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 01/03/2012] [Accepted: 04/26/2012] [Indexed: 12/24/2022]
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Bailey EF. Activities of human genioglossus motor units. Respir Physiol Neurobiol 2011; 179:14-22. [PMID: 21558022 DOI: 10.1016/j.resp.2011.04.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 04/14/2011] [Accepted: 04/17/2011] [Indexed: 01/13/2023]
Abstract
Upper airway muscles play an important role in regulating airway lumen and in increasing the ability of the pharynx to remain patent in the face of subatmospheric intraluminal pressures produced during inspiration. Due to the considerable technical challenges associated with recording from muscles of the upper airway, much of the experimental work conducted in human subjects has centered on recording respiratory-related activities of the extrinsic tongue protudor muscle, the genioglossus (GG). The GG is one of eight muscles that invest the human tongue (Abd-El-Malek, 1939). All eight muscles are innervated by the hypoglossal nerve (cranial nerve XII) the cell bodies of which are located in the hypoglossal motor nucleus (HMN) of the caudal medulla. Much of the earlier work on the respiratory-related activity of XII motoneurons was based on recordings obtained from single motor axons dissected from the whole XII nerve or from whole muscle GG EMG recordings. Detailed information regarding respiratory-related GG motor unit activities was lacking until as recently as 2006. This paper examines key findings that have emerged from the last decade of work conducted in human subjects. Wherever appropriate, these results are compared with results obtained from in vitro and in vivo studies conducted in non-human mammals. The review is written with the objective of facilitating some discussion and some new thoughts regarding future research directions. The material is framed around four topics: (a) motor unit type, (b) rate coding and recruitment, (c) motor unit activity patterns, and (d) a compartment based view of pharyngeal airway control.
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Affiliation(s)
- E Fiona Bailey
- Department of Physiology, College of Medicine, The University of Arizona, Tucson, AZ 85721-0093, USA.
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