Cardiopulmonary coupling analysis: changes before and after treatment with a mandibular advancement device.

PURPOSE: The aim of this study is to evaluate the changes of sleep quality in patients using a mandibular advancement device (MAD) for obstructive sleep apnea (OSA) based upon cardiopulmonary coupling (CPC). METHODS: A total of 52 patients (mean age 53.7±9.6 years, range 33-74 years) were included in this study. Of them, there were 47 males (90.4%). All subjects were diagnosed with OSA after in-laboratory full-night polysomnography and reevaluated after 3-month use of a MAD. At baseline, apnea-hypopnea index (AHI) was 33.6±17.0, Epworth sleepiness scale was 10.5±4.8, and Pittsburgh sleep quality index was 5.8±2.8. The CPC parameters were extracted from single-lead electrocardiography of polysomnography. We compared CPC parameters at baseline with those after 3-month use of a MAD. RESULTS: All respiratory indices improved with the use of MAD. However, there were no differences in the sleep architectures except N3 sleep (3.7±4.3 to 6.9±6.4%, p<0.001). The CPC parameters showed a significant improvement with the use of MAD. Low-frequency coupling (59.5±16.1 to 47.7±14.8%, p<0.001) and elevated low-frequency coupling (44.6±18.4 to 32.6±15.7%, p<0.001) significantly decreased. High-frequency coupling (28.6±16.0 to 36.5±15.7%, p=0.004) and very low frequency coupling (11.7±7.2 to 15.3±6.6%, p=0.028) significantly increased. The change of AHI significantly correlated with changes of the CPC parameters: negatively correlated with high-frequency coupling change (r=-0.572, p<0.001) and positively correlated with low-frequency and elevated low-frequency coupling changes (r=0.604 and 0.497, respectively; p<0.001 in both). However, the changes of Epworth sleepiness scale and Pittsburgh sleep quality index after MAD therapy showed no significant correlation with the changes in the CPC parameters. CONCLUSIONS: To our knowledge, this is the first study to evaluate the quality of sleep in patients using a MAD for their OSA based upon CPC analysis. Low-frequency coupling decreased as AHI improved, while high-frequency coupling increased as AHI improved. The CPC parameters showed that the sleep quality was improved by MAD therapy.