Effect of head and jaw position on respiratory-related motion of the genioglossus

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.

Regional respiratory movement of the tongue is coordinated during wakefulness and is larger in severe obstructive sleep apnoea

“…The head position was standardised by placing the Frankfort plane vertical, as head position can alter tongue movement (Cai et al . ). Foam padding was used to minimise head movement and participants were instructed to breathe through the nose with their mouth closed.…”

“…; Cai et al . ), potentially by varying the neural drive they receive (Bilston & Gandevia, ). Two subdivisions of the genioglossus have been identified in anatomical studies, as being innervated by separate branches of the medial branches of the hypoglossal nerve (Mu & Sanders, ).…”

“…It allows dynamic tissue movements to be quantified, therefore enabling the influence of respiratory mechanics and drive on the genioglossus to be determined (Axel & Dougherty, 1989). Using tagged MRI, dilatory tongue movements have been reported during respiration in healthy adults and OSA patients (Cheng et al 2008;Brown et al 2013;Cheng et al 2014;Cai et al 2016;Kwan et al 2019). Previous studies of the human upper airway indicated that the posterior region of the tongue moves anteriorly during inspiration resulting in airway dilatation (Cheng et al 2008;Kwan et al 2014Kwan et al , 2018.…”

“…Dilatory movement of the neuromuscular compartments of the genioglossus is critical to maintain pharyngeal airway patency during inspiration to counteract negative transluminal pressures that act to collapse the airway (Edwards & White, 2011;Strohl et al 2012). The observation of four dilatation patterns during inspiration suggests that the horizontal and oblique neuromuscular compartments of the tongue may be able to move independently during quiet breathing (Brown et al 2013;Cheng et al 2014;Cai et al 2016), potentially by varying the neural drive they receive . Two subdivisions of the genioglossus have been identified in anatomical studies, as being innervated by separate branches of the medial branches of the hypoglossal nerve (Mu & Sanders, 2010).…”

Measurement of large strain properties in calf muscles in vivo using magnetic resonance elastography and spatial modulation of magnetization

“…[15][16][17] This technique has been developed further to measure deformation in the calf muscles [18][19][20][21] and the tongue, and other muscles surrounding the upper airway. [22][23][24][25] Using MRE and SPAMM in combination may allow the characterization of large strain mechanical properties in vivo.…”