0564 Assessment of Tongue and Soft Palate Muscles Mechanical Properties in Patients with OSA

Abstract Introduction Soft palate muscles are crucial in the maintenance of UA patency. Different contraction tasks have been used to investigate tongue mechanical properties, but not to soft palate muscles. This study aimed to investigate the mechanical consequences of tongue and soft palate muscles fatigue in moderate-severe OSA patients. Methods 12 moderate and 8 severe patients with OSA were enrolled. Measurements include strength, endurance, and fatigue indices. During the soft palate fatiguing protocol, subjects were asked to develop repetitive intra-oral positive pressure during cheek-bulging maneuvers while wearing a mouth piece to keep the jaw opened. Tongue mechanical properties were also assessed using protrusion tasks with similar protocol. Subjects were encouraged to develop sustained maximal bulging pressure or tongue protrusion force for 5 sec every 10 sec until the peak pressure did not reach 85% of baseline maximal pressure for 2 consecutive times. The influence of age and BMI were also investigated. Results The sex, age were not significantly different between the 2 OSA groups. BMI was significantly higher in severe OSA patients (p<0.05). Overall, the tongue maximal voluntary contraction force (MVC), endurance time and total muscle work were respectively positively associated with the ones obtained from the soft palate fatiguing task (rs=0.51, 0.43, 0.66, respectively). The MVC of both tongue and soft palate muscles were positively correlated with BMI in all subjects (rs=0.43, 0.5 respectively). The recovery time from soft palate fatigue was significantly longer in moderate than severe OSA patients (270s ± 192.3s and 120s ± 0, p =0.02). Interestingly, the recovery time was positively correlated with AHI in tongue fatiguing task, while negatively correlated with supine AHI and age in soft palate fatiguing task (p<0.05). In both tasks, MVC was negatively correlated with the endurance time (p<0.05). Conclusion Moderate patients are less likely to recover from soft palate muscle fatigue. A more severe apneic disease is associated with longer recovery time from tongue fatigue, but with shorter recovery time from soft palate fatigue. Our results suggest that alteration in tongue and velopharyngeal muscles function may differ according to the severity of disease. Support SBD from IUCPQ Foundation.

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Assessment of tongue mechanical properties using different contraction tasks

Journal of Applied Physiology ◽

10.1152/japplphysiol.00934.2016 ◽

2017 ◽

Vol 123 (1) ◽

pp. 116-125 ◽

Cited By ~ 5

Author(s):

Wen-Yang Li ◽

Simon Gakwaya ◽

Didier Saey ◽

Frédéric Sériès

Keyword(s):

Mechanical Properties ◽

Mechanical Performance ◽

Upper Airway ◽

Apnea Hypopnea Index ◽

Endurance Time ◽

Tongue Muscle ◽

Muscle Work ◽

Obstructive Sleep ◽

Total Muscle ◽

Fatiguing Contractions

Inadequate upper airway (UA) dilator muscle function may play an important role in the pathophysiology of obstructive sleep apnea (OSA). To date, tongue mechanical properties have been assessed mainly using protrusion protocol with conflicting results. Performance during elevation tasks among patients with OSA remains unknown. This study aimed at assessing tongue muscle strength, strength stability, endurance time, fatigue indices, and total muscle work, using elevation and protrusion tasks with repetitive isometric fatiguing contractions in 12 normal plus mild, 17 moderate, and 11 severe patients with OSA, and to assess the influence of body mass index (BMI) and age. Endurance time was longer in protrusion than elevation task ( P = 0.01). In both tasks, endurance time was negatively correlated with baseline value of strength coefficient of variation ( P < 0.01). Compared with other groups, patients with moderate OSA had the lowest total muscle work for protrusion ( P = 0.01) and shortest endurance time ( P = 0.04), regardless of the type of task. Additionally, in patients with moderate-severe OSA, the total muscle work for both tasks was lower in nonobese compared with obese ( P < 0.05). Total muscle work for protrusion was positively correlated with apnea hypopnea index (AHI) in obese subjects ( P < 0.01). Endurance time was shorter ( P < 0.01) and recovery time longer ( P = 0.02) in the old compared with young subjects. In conclusion, the tongue is more prone to fatigue during the elevation task and in patients with moderate OSA. Obesity appeared to prevent alteration of tongue mechanical properties in patients with OSA. Baseline strength stability and endurance were related, illustrating the role of central neuromuscular output in tongue resistance to fatigue.NEW & NOTEWORTHY To our knowledge, this is the first study to assess and compare tongue function using both elevation and protrusion tasks with repetitive isometric fatiguing contractions in subjects with different OSA status. Tongue mechanical performance seemed to differ between protrusion and elevation tasks and depend on the severity of OSA.

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0566 Assessment of Soft Palate Muscle Fatigue and its Effect on Velopharyngeal Upper Airway (UA) Mechanical Properties

SLEEP ◽

10.1093/sleep/zsaa056.563 ◽

2020 ◽

Vol 43 (Supplement_1) ◽

pp. A217-A217

Author(s):

W Li ◽

S Gakwaya ◽

J Masse ◽

F Series

Keyword(s):

Mechanical Properties ◽

Muscle Fatigue ◽

Soft Palate ◽

Dynamic Properties ◽

Upper Airway ◽

Positive Pressure ◽

Linear Resistance ◽

Moderate Disease ◽

Maximal Peak ◽

Mechanical Performances

Abstract Introduction Soft palate muscles are crucial in the maintenance of UA patency. This study aimed to investigate the fatigability of soft palate muscles and to quantify its effects on velopharyngeal UA dynamic properties in OSA patients and control subjects. Methods 8 control (AHI ≤ 10 /h), 21 OSA patients (13 with mild/moderate disease: 10 /h < AHI ≤ 20 /h and 8 with moderate/severe: AHI > 20/h) were included in the study. Subjects were asked to develop repetitive intra-oral positive pressure during cheek-bulging maneuvers while wearing a mouth piece to keep the jaw opened. Subjects were asked to develop sustained maximal bulging pressure for 5 sec every 10 sec until the peak pressure could not reach 85% of baseline maximal pressure for 2 consecutive times. UA dynamic properties were assessed by measuring instantaneous airflow and velopharyngeal pressure in response to phrenic nerve magnetic stimulation (PNMS) performed before, immediately and every 3 minutes after the fatiguing protocol for a maximum of 30 minutes’ recovery time. UA closing pressure (Pcrit) was estimated by modeling the flow/pressure relationship in response to PNMS. Results The sex, age, BMI and the soft palate mechanical properties (including the baseline strength, endurance time, total muscle work) did not significantly differ between the 3 groups. Maximal peak bulging pressure measured using cheek-bulging maneuver significantly changed following the fatigue task (p < 0.05). Baseline velopharyngeal Pcrit were less negative in moderate/severe OSA group compared to mild/moderate OSA (-6.5±2.6 vs. -11.9±3.2, p < 0.05). In mild/moderate OSA patients, PNMS-induced drop in maximal instantaneous airflow tend to increase 3 mins after the fatiguing trial compared to baseline (22.7±21.1 l.s-1vs. 9.6±5.8 l.s-1, p < 0.1), and their Velopharyngeal linear resistance 3 mins after the fatiguing trial tend to be higher than the moderate/severe OSA group (3.9 ± 5.0 cmH2O·l−1·s−1 vs. 1.8 ± 1.1 cmH2O·l−1·s−1, p< 0.1). Conclusion The cheek-bulging maneuver could induce soft palate muscle fatigue, with no difference observed in soft palate mechanical performances among patients with different OSA severity. The fatiguing maneuver could further alter velopharyngeal UA mechanical properties in patients with mild/moderate OSA. Support SBD from IUCPQ Foundation

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Acute passive stretching alters the mechanical properties of human plantar flexors and the optimal angle for maximal voluntary contraction

European Journal of Applied Physiology ◽

10.1007/s00421-004-1265-4 ◽

2004 ◽

Vol 93 (5-6) ◽

pp. 614-623 ◽

Cited By ~ 95

Author(s):

Derek E. Weir ◽

Jill Tingley ◽

Geoffrey C. B. Elder

Keyword(s):

Mechanical Properties ◽

Maximal Voluntary Contraction ◽

Voluntary Contraction ◽

Plantar Flexors ◽

Optimal Angle ◽

Passive Stretching

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Sex Differences in the Morphological and Mechanical Properties of the Achilles Tendon

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18178974 ◽

2021 ◽

Vol 18 (17) ◽

pp. 8974

Author(s):

Xini Zhang ◽

Liqin Deng ◽

Songlin Xiao ◽

Lu Li ◽

Weijie Fu

Keyword(s):

Mechanical Properties ◽

Achilles Tendon ◽

Maximum Voluntary Contraction ◽

Voluntary Contraction ◽

Cross Sectional Area ◽

Morphological Properties ◽

Sectional Area ◽

Cross Sectional ◽

Force Peak ◽

Strain Stress

Background: Patients with Achilles tendon (AT) injuries are often engaged in sedentary work because of decreasing tendon vascularisation. Furthermore, men are more likely to be exposed to AT tendinosis or ruptures. These conditions are related to the morphological and mechanical properties of AT, but the mechanism remains unclear. This study aimed to investigate the effects of sex on the morphological and mechanical properties of the AT in inactive individuals. Methods: In total, 30 inactive healthy participants (15 male participants and 15 female participants) were recruited. The AT morphological properties (cross-sectional area, thickness, and length) were captured by using an ultrasound device. The AT force–elongation characteristics were determined during isometric plantarflexion with the ultrasonic videos. The AT stiffness was determined at 50%–100% maximum voluntary contraction force. The AT strain, stress, and hysteresis were calculated. Results: Male participants had 15% longer AT length, 31% larger AT cross-sectional area and 21% thicker AT than female participants (p < 0.05). The plantarflexion torque, peak AT force, peak AT stress, and AT stiffness were significantly greater in male participants than in female participants (p < 0.05). However, no significant sex-specific differences were observed in peak AT strain and hysteresis (p > 0.05). Conclusions: In physically inactive adults, the morphological properties of AT were superior in men but were exposed to higher stress conditions. Moreover, no significant sex-specific differences were observed in peak AT strain and hysteresis, indicating that the AT of males did not store and return elastic energy more efficiently than that of females. Thus, the mechanical properties of the AT should be maintained and/or improved through physical exercise.

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Correlation between Porosity and Electrical-Mechanical Properties of Carbon Nanotube Buckypaper with Various Porosities

Journal of Nanomaterials ◽

10.1155/2015/945091 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9 ◽

Cited By ~ 6

Author(s):

Ling Liu ◽

Qiaoxin Yang ◽

Jingwen Shen

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Carbon Nanotube ◽

The Other ◽

Positive Pressure ◽

Filtration Method ◽

Elongation At Break ◽

Conductive Materials ◽

Wide Range ◽

Electrical Conductivities

Porous carbon nanotube (CNT) buckypapers (BPs) with various porosities were obtained by using a positive pressure filtration method. The porosity of the BPs fell into a wide range of 11.3–39.3%. Electrical conductivities and tensile mechanical properties of the prepared BPs were then measured and correlated with the porosity of the CNT BPs. Results demonstrated that the conductivities, tensile strength, and elastic modulus of the BPs could decrease by increasing their porosity. The elongation at break of the BPs on the other hand did increase significantly, suggesting improved toughness of the BPs. The obtained electrical conductivity and tensile strength of the porous BPs can reach nearly 0.6 S/m and 26 MPa, respectively, which may be potentially useful in composites reinforcement and conductive materials.

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Effects of transmural pressure on brachial artery mean blood velocity dynamics in humans

Journal of Applied Physiology ◽

10.1152/japplphysiol.00443.2002 ◽

2002 ◽

Vol 93 (6) ◽

pp. 2137-2146 ◽

Cited By ~ 23

Author(s):

Mary E. J. Lott ◽

Michael D. Herr ◽

Lawrence I. Sinoway

Keyword(s):

Brachial Artery ◽

Pressure Change ◽

Blood Velocity ◽

Voluntary Contraction ◽

Transmural Pressure ◽

Positive Pressure ◽

Myogenic Response ◽

Vascular Responses ◽

Pressure Changes ◽

Handgrip Contractions

The effects of changes in transmural pressure on brachial artery mean blood velocity (MBV) were examined in humans. Transmural pressure was altered by using a specially designed pressure tank that raised or lowered forearm pressure by 50 mmHg within 0.2 s. Brachial MBV was measured with Doppler directly above the site of forearm pressure change. Pressure changes were evoked during resting conditions and after a 5-s handgrip contraction at 25% maximal voluntary contraction. The handgrip protocol selected was sufficiently vigorous to limit flow and sufficiently brief to prevent autonomic engagement. Changes in transmural pressure evoked directionally similar changes in MBV within 2 s. This was followed by large and rapid adjustments [−2.14 ± 0.24 cm/s (vasoconstriction) during negative pressure and +2.14 ± 0.45 cm/s (vasodilatation) during positive pressure]. These adjustments served to return MBV to resting levels. This regulatory influence remained operative after 5-s static handgrip contractions. Of note, changes in transmural pressure were capable of altering the timing of the peak MBV response (5 ± 0, 2 ± 0, 6 ± 1 s ambient, negative, and positive pressure, respectively) as well as the speed of MBV adjustment (−2.03 ± 0.18, −2.48 ± 0.15, −0.84 ± 0.19 cm · s−1 · s−1ambient, negative, and positive pressure, respectively) after handgrip contractions. Vascular responses, seen with changes in transmural pressure, provide evidence that the myogenic response is normally operative in the limb circulation of humans.

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Continuous positive-pressure ventilation does not alter ventricular pressure-volume relationship

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1981.240.6.h821 ◽

1981 ◽

Vol 240 (6) ◽

pp. H821-H826 ◽

Cited By ~ 3

Author(s):

J. E. Fewell ◽

D. R. Abendschein ◽

C. J. Carlson ◽

E. Rapaport ◽

J. F. Murray

Keyword(s):

Mechanical Properties ◽

Positive Pressure Ventilation ◽

Venous Return ◽

Intermittent Positive Pressure Ventilation ◽

Left Ventricular ◽

Positive Pressure ◽

Volume Relationship ◽

Pressure Volume Relationship ◽

The Right ◽

Continuous Positive Pressure

To determine whether alterations in the mechanical properties (i.e., stiffening) of the right and left ventricles contribute to the decrease in right and left ventricular end-diastolic volumes during continuous positive-pressure ventilation (CPPV), we studied six dogs anesthetized with chloralose urethane and ventilated with a volume ventilator. We varied ventricular volumes by withdrawing or infusing blood. Pressure-volume curves, constructed by plotting transmural ventricular end-diastolic pressures against ventricular end-diastolic volumes, did not change during CPPV (12 cmH2O positive end-expiratory pressure) compared to intermittent positive-pressure ventilation (IPPV, 0 cmH2O end-expiratory pressure). We conclude that decreased ventricular end-diastolic volumes during CPPV result primarily from a decrease in venous return. Alterations in the mechanical properties of the ventricles do not play a significant role in this response.

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