Tongue peak pressure: a tool to aid in the identification of obstruction sites in patients with obstructive sleep apnea/hypopnea syndrome

Purpose of this study was to evaluate whether tongue peak pressure measured using the Iowa Oral Performance Instrument is correlated with the topographic site of obstruction in patients with obstructive sleep apnea/hypopnea syndrome observed during drug-induced sleep endoscopy. Thirty-five consecutive adult patients (29 men, 6 women) were prospectively enrolled after having been diagnosed with severe obstructive sleep apnea/hypopnea syndrome by polysomnography. An apnea-hypopnea index > 30 was confirmed, and age, gender, and body mass index were recorded by Epworth Sleepiness Scale questionnaire, and a thorough evaluation of the upper airway by video-flexible endoscopy. Twenty healthy controls according to age and sex were chosen for IOPI measurements. After drug-induced sleep endoscopy, a topographic diagnosis was done using the VOTE classification. Tongue and lip peak pressures were both measured using the Iowa Oral Performance Instrument in all patients and in 20 healthy controls. Main outcomes and measures: the correlations between office findings, Iowa Oral Performance Instrument measures, and the VOTE tongue classification during drug-induced sleep endoscopy (T0, T1, T2) were then investigated. RESULTS: The average Iowa Oral Performance Instrument tongue and lip pressure were 44.02 ± 12.29 and 15.03 ± 3.71 kPa, respectively. The Iowa Oral Performance Instrument scores were both significantly lower than values in healthy controls (P < 0.001). The VOTE classification referring to the tongue position was T0 in 13 cases (37.1%), T1 in 12 cases (34.3%), and T2 in 10 cases (28.6%). A significant correlation was found between the Iowa Oral Performance Instrument tongue pressure and the T size during drug-induced sleep endoscopy (Kruskal-Wallis χ² 25.82; P ≤ 0.001). CONCLUSIONS: In our experience, the Iowa Oral Performance Instrument is a useful tool for evaluating tongue collapse for the topographic diagnosis of patients with obstructive sleep apnea/hypopnea syndrome.