Prevalence and patterns of tongue deformation in obstructive sleep apnea: A whole-night simultaneous ultrasonographic and polysomnographic study

Tongue deformation during whole-night natural sleep in adult patients with obstructive sleep apnea has not been well evaluated. Through simultaneous ultrasonography and polysomnography during whole-night sleep, we examined the prevalence and patterns of tongue depth changes and their relationship with the severity of obstructive sleep apnea. Sixty consecutive eligible adults presenting with symptoms suggesting obstructive sleep apnea were enrolled. We observed that 88.4% (38/43) of patients with obstructive sleep apnea exhibited a significant increase in the maximum ultrasonographic tongue depth when hypopnea or apnea occurred during sleep. A mixed-model analysis of variance demonstrated that compared with patients with primary snoring or mild obstructive sleep apnea, those with moderate to severe obstructive sleep apnea have significantly greater maximum ultrasonographic tongue depth during respiratory events (p =.0047). We identified three different ultrasonographic patterns of tongue deformation, namely en bloc, tongue body and tongue base. Approximately 82% (27/33) of patients with moderate to severe obstructive sleep apnea demonstrated an en bloc tongue deformation. By contrast, 70% (19/27) of primary snorers or patients with mild obstructive sleep apnea showed a tongue body obstruction. Recognizing the prevalence and patterns of tongue deformation during sleep may provide insights into pathogenesis and treatment decisions in patients with obstructive sleep apnea. Future studies are warranted to verify the treatment results of various tongue procedures by using this approach.