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.