The human genioglossus response to negative airway pressure: stimulus timing and route of delivery

Doherty, Liam S.; Cullen, John P.; Nolan, P.; McNicholas, Walter T.

doi:10.1113/expphysiol.2007.039677

Cited by 13 publications

(14 citation statements)

References 28 publications

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“…On the other hand, although anesthetized and decerebrate animal models allow access to all of the tongue muscles, the influence of drugs precludes the study of natural state changes on the respiratory drive to the motoneuron pool. Moreover, studies are typically done in tracheotomized animals, allowing airflow to bypass the upper airway, which greatly disturbs not only the natural function of the upper airway, but presumably the neural drive to the hypoglossal motoneuron pool (Berry et al, 2003; Chamberlin et al, 2007; Doherty et al, 2008; Eckert et al, 2007; Horner et al, 1991; Leiter and Daubenspeck, 1990; Malhotra et al, 2002; Mathew et al, 1982; van Lunteren et al, 1984). …”

Section: Introductionmentioning

confidence: 99%

Respiratory related control of hypoglossal motoneurons––Knowing what we do not know

Fregosi

2011

Respiratory Physiology & Neurobiology

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Because tongue position and stiffness help insure that the pharyngeal airspace is sufficiently open during breathing, the respiration-related behavior of the tongue muscles has been studied in detail, particularly during the last two decades. Although eight different muscles act upon the mammal tongue, we know very little about the respiration-related control of the majority of these, and almost nothing about how they work together as a complex electro-mechanical system. Other significant gaps include how hypoglossal motoneuron axons find their appropriate muscle target during development, whether the biophysical properties of hypoglossal motoneurons driving different muscles are the same, and how afferent information from cardiorespiratory reflex systems is transmitted from major brainstem integrating centers to the hypoglossal motoneuron pool. This brief review outlines some of these issues, with the hope that this will spur research in the field, ultimately leading to an improved understanding of the respiration-related control of the mammalian tongue musculature.

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Section: Introductionmentioning

confidence: 99%

Respiratory related control of hypoglossal motoneurons––Knowing what we do not know

Fregosi

2011

Respiratory Physiology & Neurobiology

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“…Mid-inspiration Early expiration Mid-expiration Short latency excitation (<40 ms) 12/12 (100%) 11/12 (92%) 6/12 (50%) * 4/10 (40%) * , † Long latency excitation (>40 ms) 0/12 (0%) 1/12 (8%) 3/12 (25%) 6/10 (60%) * , † Suppression after excitation 3/12 (25%) 4/12 (33%) 1/12 (8%) 0/10 (0%) Suppression before excitation 0/12 (0%) 0/12 (0%) 1/12 (8%) 1/10 (10%) * Significant difference from early inspiration; † significant difference from mid-inspiration; P < 0.05. between inspiration and expiration (Doherty et al 2008). This suggests that the current findings either are specific to people with OSA or may relate to other differences in methodology.…”

Section: Early Inspirationmentioning

confidence: 72%

“…Earlier studies (Woodall et al 1989;Horner et al 1991;Wheatley & White, 1993;Tantucci et al 1998) have shown differences in the genioglossus reflex depending on the timing of the negative pressure with the most robust responses during end expiration and early inspiration. In contrast, a more recent study (Doherty et al 2008) showed no change in the genioglossus response to negative pressure delivered at different time points during the respiratory cycle.…”

Section: Introductionmentioning

confidence: 67%

Changes in pharyngeal collapsibility and genioglossus reflex responses to negative pressure during the respiratory cycle in obstructive sleep apnoea

Osman

Carberry

Gandevia

et al. 2020

The Journal of Physiology

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Key pointsr Impaired pharyngeal anatomy and increased airway collapsibility is a major cause of obstructive sleep apnoea (OSA) and a mediator of its severity.r Upper airway reflexes to changes in airway pressure provide important protection against airway closure. r This study shows increased pharyngeal collapsibility and attenuated genioglossus reflex responses during expiration in people with OSA.Abstract Upper airway collapse contributes to obstructive sleep apnoea (OSA) pathogenesis. Pharyngeal dilator muscle activity varies throughout the respiratory cycle and may contribute to dynamic changes in pharyngeal collapsibility. However, whether upper airway collapsibility and reflex responses to changes in airway pressure vary throughout the respiratory cycle in OSA is unclear. Thus, this study quantified differences in upper airway collapsibility and genioglossus electromyographic (EMG) activity and reflex responses during different phases of the respiratory cycle. Twelve middle-aged people with OSA (2 female) were fitted with standard polysomnography equipment: a nasal mask, pneumotachograph, two fine-wire intramuscular electrodes into the genioglossus, and a pressure catheter positioned at the epiglottis and a second at the choanae (the collapsible portion of the upper airway). At least 20 brief (ß250 ms) pressure pulses (ß−11 cmH 2 O at the mask) were delivered every 2-10 breaths during four conditions: (1) early inspiration, (2) mid-inspiration, (3) early expiration, and (4) mid-expiration. Mean baseline genioglossus EMG activity 100 ms prior to pulse delivery Amal Osman is a Research Associate at the Adelaide Institute for Sleep Health, Flinders University. She completed her PhD at the University of New South Wales and Neuroscience Research Australia. She is investigating development of simple clinical tools to measure upper airway collapsibility in obstructive sleep apnoea, a critical component in the pathogenesis of this common sleep-related breathing disorder. Current interests include understanding the mechanisms that contribute to airway closure in sleep apnoea. The hope is that this work brings us closer to developing new clinical tools to predict and optimize responses to targeted and novel treatments. J Physiol 598.3 and genioglossus reflex responses were quantified for each condition. The upper airway collapsibility index (UACI), quantified as 100 × (nadir choanal − epiglottic pressure)/nadir choanal pressure during negative pressure pulses, varied throughout the respiratory cycle (early inspiration = 43 ± 25%, mid-inspiration = 29 ± 19%, early expiration = 83 ± 19% and mid-expiration = 95 ± 11% (mean ± SD) P < 0.01). Genioglossus EMG activity was lower during expiration (e.g. mid-expiration vs. mid-inspiration = 76 ± 23 vs. 127 ± 41% of early-inspiration, P < 0.001). Similarly, genioglossus reflex excitation was delayed (39 ± 11 vs. 23 ± 7 ms, P < 0.001) and reflex excitation amplitude attenuated during mid-expiration versus early inspiration (209 ± 36 vs. 286 ± 80%, P = 0.009). These findings ...

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“…Also, the route of breathing may affect the magnitude and/or pattern of muscle response to inspiratory obstruction: EMG:Pes measurements were performed with an external resistive load and a mouthpiece, and oral breathing has been shown to reduce the GG response to hypoxaemia (Tafil‐Klawe & Klawe, ). However, the GG‐EMG response to negative pressure in the upper airway is not affected by the route of application of the negative pressures (Doherty, Cullen, Nolan, & McNicholas, ).…”

Section: Discussionmentioning

confidence: 99%

Peri‐pharyngeal muscle response to inspiratory loading: comparison of patients with OSA and healthy subjects

Oliven

Cohen

Somri

et al. 2018

Journal of Sleep Research

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Upper airway patency to airflow and the occurrence of obstructive sleep apnea involve a complex interplay between pharyngeal anatomy and synergic co-activation of peri-pharyngeal muscles. In previous studies we observed large differences in the response to sleep-associated flow limitation between the genioglossus and other (non-GG) peri-pharyngeal muscles. We hypothesized that similar differences are present also during wakefulness. In the present study we compared the response to inspiratory loading of the genioglossus electromyogram and four other peri-pharyngeal muscles. Studies were performed in eight obstructive sleep apnea patients, seven age-matched healthy subjects and five additional younger subjects. Electromyogram activity was evaluated over a range of negative oesophageal pressures and expressed as % of maximal electromyograms. In healthy subjects, the slope response to inspiratory loading (electromyogram/pressures) was similar for the genioglossus and non-GG muscles studied. However, the electromyogram responses were significantly higher in the young subjects compared with older subjects. In contrast, in the obstructive sleep apnea patients, the electromyogram/pressure response of the non-GG muscles was similar to that of the age-matched healthy subjects, whereas the slope response of the genioglossus electromyogram was significantly higher than non-GG muscles. We conclude that both age and the presence of obstructive sleep apnea affect the response of peri-pharyngeal muscles to inspiratory loading. In patients with obstructive sleep apnea the genioglossus seems to compensate for mechanical disadvantages, but non-GG muscles apparently are not included in this neuromuscular compensatory mechanism. Our current and previous findings suggest that attempts to improve obstructive sleep apnea with myofunctional therapy should put added emphasis on the training of non-GG muscles.

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The human genioglossus response to negative airway pressure: stimulus timing and route of delivery

Cited by 13 publications

References 28 publications

Respiratory related control of hypoglossal motoneurons––Knowing what we do not know

Respiratory related control of hypoglossal motoneurons––Knowing what we do not know

Changes in pharyngeal collapsibility and genioglossus reflex responses to negative pressure during the respiratory cycle in obstructive sleep apnoea

Peri‐pharyngeal muscle response to inspiratory loading: comparison of patients with OSA and healthy subjects

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