Assessment of tongue mechanical properties using different contraction tasks

Abstract

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 ( = 0.01). In both tasks, endurance time was negatively correlated with baseline value of strength coefficient of variation ( < 0.01). Compared with other groups, patients with moderate OSA had the lowest total muscle work for protrusion ( = 0.01) and shortest endurance time ( = 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 ( < 0.05). Total muscle work for protrusion was positively correlated with apnea hypopnea index (AHI) in obese subjects ( < 0.01). Endurance time was shorter ( < 0.01) and recovery time longer ( = 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. 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.

Hypoglossal nerve stimulation therapy does not alter tongue protrusion strength and fatigability in obstructive sleep apnea

“…In another study, lower tongue total muscle work was detected in nonobese compared to untreated obese patients with moderate to severe OSA. 49 In this study patients with OSA were also not treated, which could explain the differing results compared to our cohort. In summary, BMI seems to affect tongue fatigue in untreated nonobese patients with OSA but not in treated nonobese patients with OSA.…”

Maximum isometric tongue force in patients with obstructive sleep apnoea

“…The comparability to our study is limited since fatigue was tested in vitro after a genioglossus biopsy. In another study, lower tongue total muscle work was detected in non-obese compared to untreated obese patients with moderate to severe OSA [25]. Summarizing the studies BMI seems not to be influencing tongue fatigue in treated non-obese OSA patients but in untreated non-obese OSA patients.…”

Relationship between fat distribution and tongue strength in persons with and without obstructive sleep apnea

“…Overall results of this study showed that increased total body fat % and visceral fat % resulted in increased tongue strength during speech and swallowing tasks, respectively. While limited, other studies have shown similar results Li 13 and Ulrich Sommer. 18 Additionally, other research comparing the tongue strength of active and non-active adults shows that active adults have significantly stronger anterior and posterior maximal values.…”

“…11 Additionally, persons with moderate OSA have been shown to be more susceptible to tongue muscle fatigue. 12,13 Moreover, tongue strengthening (i.e., oropharyngeal) exercises and hypoglossal nerve stimulation have been shown to reduce the severity and symptoms for persons with moderate OSA. 14,15 Conversely, there is evidence suggesting that tongue strength may not play a role with OSA.…”

“…2 Limited data suggests a positive relationship between tongue strength and BMI in typical healthy persons 18 and obese persons with OSA. 13 Additional insight on the impact of obesity on strength can be gleamed from the limb literature which generally shows that obesity is associated with reduced muscular function. 19 However, it may not be appropriate to generalize results from the limb literature as the muscles associated with speech and swallowing have been shown to be unique from the limb muscles in multiple ways, including muscle fiber composition.…”