Dynamic alterations of tongue in OSAHS during sleep

Objectives: To evaluate the dynamic changes of the tongue in patients with obstructive sleep apnoea hypopnea syndrome (OSAHS) and normal people during sleep and awake by using Ultrafast Magnetic Resonance Imaging (UMRI). Methods: UMRI was undertaken on the upper airway in 21 OSAHS patients and 20 normal people. A series of midline sagittal images of the upper airway were obtained. The dynamic alterations of the tongue size and the distance from the tongue to X axis (an extended line from the anterior nasal spine to posterior nasal spine) and Y axis (a perpendicular line from the center of the pituitary to the X axis) were measured. Results: In wakefulness, the maximal and minimal values of the tongue's upper sagittal diameter were less in OSAHS group than the control group(P<0.01) while the differences between the maximal and minimal values of the tongue's vertical diameter and the maximal values between posterior border and retropharyngeal wall on the upper and central part of the tongue were larger(P<0.05).The differences of the maximal and minimal values of the distance between the inferior border of the tongue to the X axis were larger in OSAHS group than the control group(P<0.01). In sleeping, the maximum and the differences between the maximal and minimal values of the size and the position of each part of the tongue in OSAHS were larger than the control group (P<0.05) while the minimal values mentioned were lesser (P<0.01). Conclusion:In wakefulness, there were few significant differences in the size and dynamic changes between the OSAHS group and the normal group. In sleeping, the difference extent of the size and dynamic changes of the tongue in the OSAHS group were larger than the normal group . The tongue had significant downward movement in the OSAHS group which may aggravate the upper airway obstruction.