Dynamic tongue area measurements in ultrasound images for adults with obstructive sleep apnea.

Obstructive sleep apnea is a chronic breathing disorder where the recursive collapse of the upper airway causes cessation of airflow during sleep. Quantitative assessments of dynamic tongue motion may provide a better understanding of the mechanism of obstructive sleep apnea. Tongue area changes, in submental ultrasound images recorded during wakefulness from normal breathing by the Müller manoeuvre, were tracked using the modified optical flow-based method. The results demonstrated that patients with obstructive sleep apnea had a larger mid-sagittal tongue area compared to the control group (during normal breathing, p = .004, during the Müller manoeuvre p = .005, and differences between normal breathing and the Müller manoeuvre, p = .01). Tongue area measurements were significantly different in patients with varying severity of OSA during normal breathing and during the Müller manoeuvre, and had differences between normal breathing and the Müller manoeuvre (p = .005, p = .008 and p = .03, respectively). Patients with moderate or severe obstructive sleep apnea exhibited minimal movement of the tongue. In contrast, normal controls and patients with mild obstructive sleep apnea demonstrated bidirectional tongue motions during a transition from normal breathing to the Müller manoeuvre in wakefulness. Identifying different patterns of deformation and displacement of the tongue may have potential in evaluating the presence and the pathogenesis of OSA.