Effects of respiratory training on obstructive sleep apnea: systematic review and meta-analysis

Investigating phase coupling of respiratory sinus arrhythmia and slow wave sleep in obstructive sleep apnea patients with and without depression

Phase coherence (λ) between respiratory sinus arrhythmia (RSA) and respiration has emerged as a promising metric for assessing the role of autonomic nervous system (ANS) activity and slow wave sleep (SWS) activities in healthy subjects. This study aims to investigate how λ and SWS activity differ between Obstructive Sleep Apnea (OSA) patients with and without major depressive disorder (MDD) during overnight sleep and explore whether the correlation between λ and SWS activity exists among those OSA patients compared to healthy individuals. Overnight electroencephalogram (EEG), electrocardiograms (ECG), and breathing using plethysmography were recorded from 104 subjects, including 35 healthy individuals (control), 34 OSA subjects with MDD (OSAD+) and 35 OSA subjects without MDD (OSAD+). Slow wave activity was computed by the amplitude envelope of the EEG δ-wave (0.5-4 Hz). The interbeat intervals (RRI) and respiratory movement were derived from ECG. RRI and respiration were resampled at a frequency of 10 Hz, and the band passed filtered within the range of 0.1-0.4 Hz before the Hilbert transform was used to extract instantaneous phases of the RSA and respiration. From the analytical signal of the Hilbert transform, the phase coherence (λ) and amplitude of RSA (ARSA) were quantified. Additionally, the heart rate variability (HRV) features were calculated. Our results showed that overnight λ was significantly greater, while the Low Frequency (LF) and High Frequency (HF) components of the HRV were significantly lower in OSAD+ compared to OSAD-. In addition, overnight δ-wave activity was greater in OSAD- compared to both OSAD+ and control groups. Using auto- and cross-correlation analyses, we found that overnight profiles of λ and δ-wave were correlated only in healthy individuals compared to OSAD+ and OSAD-, indicating that sleep apnea may only have an impact on this cortical-cardiorespiratory correlation rather than depression. Our findings suggest that λ and SWS activity appear to be biomarkers for assessing depression in OSA patients, whereas their correlation pattern may serve as a marker for only OSA. This could enhance diagnostic precision and provide valuable insights into the complex physiological mechanisms underlying the corambid of OSA and MDD.

Efficacy of oropharyngeal exercises as an adjuvant therapy for obstructive sleep apnea: A randomized controlled trial

PURPOSE

Some patients with mild-to-moderate obstructive sleep apnea (OSA) undergoing mandibular advancement device (MAD) therapy may exhibit residual sleep-breathing abnormalities. These cases require adjunctive treatment to further reduce the remaining airway inadequacy, which may affect the health and quality of life. This clinical trial was conducted since the oropharyngeal exercise, which aims to enhance the muscular function of the upper airway, combined with MAD, is unknown. We assessed the possible improvements in respiratory event parameters and lip and tongue physiological properties in patients with OSA who received oropharyngeal exercises for 2 months as an adjunct to MAD therapy.

METHODS

Twenty-three participants with OSA who had been using MAD but still had residual apnea-hypopnea were randomly allocated to either the oropharyngeal exercise (OE group; N=12) or the sham exercise group (N=11). Lip and tongue strength, endurance, daytime sleepiness, respiratory event index (REI), and the lowest oxygen saturation (SpO2 nadir) were determined.

RESULTS

Within and between the treatment groups, no significant improvement in the REI or SpO2 nadir was found. In both groups, there was a significant reduction in the Epworth Sleepiness Scale at 2 months (OE, P = 0.02; control, P = 0.02). In the OE group, lip endurance (P = 0.03), anterior tongue strength (P = 0.02), and endurance (P = 0.02) increased after 2-month of exercise, but only anterior tongue endurance increased significantly compared with the sham control (P = 0.01).

CONCLUSIONS

This study found that adjunctive OE to MAD showed no additive effect in treating patients with moderate OSA who had a mild residual apnea-hypopnea index following MAD treatment. However, the exercises successfully enhanced lip and anterior tongue endurance, as well as anterior tongue strength.

Effects of respiratory exercises in sleep bruxism and associated obstructive sleep apnea: a double-blind, placebo-controlled randomized clinical trial

PURPOSE

The aim of this study is to assess the effects of respiratory exercises (inspiratory and expiratory) in individuals with sleep bruxism (SB) and associated obstructive sleep apnea (OSA).

METHODS

This is a double-blind, placebo-controlled randomized clinical trial including individuals with SB and associated respiratory events in OSA. Respiratory physical therapy was performed using inspiratory (Threshold® IMT), expiratory (Threshold® PEP) muscle training, and compared with a placebo group. A total of 30 daily respiratory cycles (inspiration and expiration) were performed five times a week for 12 weeks. Individuals were reassessed at two times, at baseline (T1) and after 12 weeks of training (T2) by means of the Pittsburgh Sleep Quality Index and Polysomnography.

RESULTS

Awakening was significantly different (p ≤ 0.05) between the inspiratory group and placebo 12 weeks after respiratory physical therapy. The number of contractions of the masseter muscle differed between the inspiratory, expiratory, and placebo groups (p ≤ 0.05).

CONCLUSION

Respiratory physical therapy for OSA improved awaking levels in 80 and 67% of the number of masseter muscle contractions, when compared to placebo.

TRIAL REGISTRATION

Brazilian Registry of Clinical Trials (No. RBR-9F6JKM).

Modified oropharyngeal muscle training and scientific vocalization are effective in treating mild-to-moderate obstructive sleep apnea hypoventilation syndrome in adults

BACKGROUND

Obstructive Sleep Apnea-hypopnea Syndrome (OSAHS) has become a major public health challenge globally. Most patients have a concomitant voice disorder. The existing treatment methods have problems.Aims/Objectives: This study investigates the therapeutic effect of adding scientific vocalization to oropharyngeal muscle training on OSAHS patients.

MATERIAL AND METHODS

A total of 30 patients were selected from September 2020 to October 2022. They underwent overnight polysomnography (PSG) and were identified as having mild to moderate obstructive sleep apnea hypoventilation syndrome. They were then chosen for a three-month period of modified oropharyngeal muscle training combined with scientific vocalization.

RESULTS

Out of the 30 selected patients, 26 patients completed the training. Results showed a significant changes in multiple sleep-related indicators. he clinical outcomes were as follows: 7 cases were cured, 13 cases were effective, and 6 cases were ineffective. The overall effective rate was 76.92%.

CONCLUSIONS AND SIGNIFICANCE

The combination of oropharyngeal muscle training and scientific vocalization for the treatment of mild to moderate OSAHS in adults significantly improves several measures used in the treatment of the condition. The method is easy to learn, effective, safe to use, and affordable. It provides more options for the treatment of OSAHS.

Obstructive Sleep Apnea and Role of the Diaphragm

Obstructive sleep apnea (OSA) causes multiple local and systemic pathophysiological consequences, which lead to an increase in morbidity and mortality in patients suffering from this disorder. OSA presents with various nocturnal events of apnoeas or hypopneas and with sub-clinical airflow limitations during wakefulness. OSA involves a large percentage of the population, particularly men, but the estimate of OSA patients could be much broader than data from the literature. Most of the research carried out in the muscle field is to understand the causes of the presence of chronic nocturnal desaturation and focus on the genioglossus muscle and other muscles related to dilating the upper airways. Sparse research has been published regarding the diaphragm muscle, which is the main muscle structure to insufflate air into the airways. The article reviews the functional anatomy of the muscles used to open the upper respiratory tract and the non-physiological adaptation that follows in the presence of OSA, as well as the functional anatomy and pathological adaptive aspects of the diaphragm muscle. The intent of the text is to highlight the disparity of clinical interest between the dilator muscles and the diaphragm, trying to stimulate a broader approach to patient evaluation.

Respiratory Muscle Training in Patients with Obstructive Sleep Apnoea: A Systematic Review and Meta-Analysis

Background: Effective treatments for obstructive sleep apnoea (OSA) include positive pressure, weight loss, oral appliances, surgery, and exercise. Although the involvement of the respiratory muscles in OSA is evident, the effect of training them to improve clinical outcomes is not clear. We aimed to determine the effects of respiratory muscle training in patients with OSA. Methods: A systematic review was conducted in seven databases. Studies that applied respiratory muscle training in OSA patients were reviewed. Two independent reviewers analysed the studies, extracted the data and assessed the quality of evidence. Results: Of the 405 reports returned by the initial search, eight articles reporting on 210 patients were included in the data synthesis. Seven included inspiratory muscle training (IMT), and one included expiratory muscle training (EMT). Regarding IMT, we found significant improvement in Epworth sleepiness scale in −4.45 points (95%CI −7.64 to −1.27 points, p = 0.006), in Pittsburgh sleep quality index of −2.79 points (95%CI −4.19 to −1.39 points, p < 0.0001), and maximum inspiratory pressure of −29.56 cmH2O (95%CI −53.14 to −5.98 cmH2O, p = 0.01). However, the apnoea/hypopnea index and physical capacity did not show changes. We did not perform a meta-analysis of EMT due to insufficient studies. Conclusion: IMT improves sleepiness, sleep quality and inspiratory strength in patients with OSA.