Tongue Measurements May Be New Tool in OSA Therapy

Mandibular advancement splints (MAS) are often used to safely treat mild to moderate OSA, however, the devices’ efficacy in actual treatment has been difficult to predict.

Whitney Mostafiz of the Harvard School of Dental Medicine headed the investigation into the implications of how craniofacial size, upper-airway soft tissue volume, or the relationships between them might affect the outcome of MAS treatment.

Testing included 49 adult OSA patients in good general health who wore custom-fitted MAS as they slept.

Nearly half (24) of the test subjects responded to treatment when therapy concluded at approximately six weeks. Using polysomnography to measure outcomes, researchers found the baseline apnea-hypopnea index among respondents was reduced by at least 50%, indicating a less severe level of sleep apnea.

Tongue cross-sectional area (CSA) was measured in a subset of 28 patients, including 12 responders and 16 non-responders. The measurements were taken using cephalometric soft-tissue imaging. Responders had a larger tongue CSA than non-responders, but there was no difference in the bony oral enclosure CSA. The ratio of tongue to bony enclosure CSA significantly differed between responders and non-responders, indicating the ratio as a significant predictor of response to treatment.

Measurements of tongue cross-sectional areas revealed larger tongue CSAs were found among responders than non-responders, while no differences existed in CSAs of the bony oral enclosure.

Because patients who responded to MAS treatment exhibited a larger tongue volume in relationship to oral cavity size, the researchers suggest that properly determining this ratio may help predict MAS treatment success.