Improving the Diagnostic Ability of the Sleep Apnea Screening System Based on Oximetry by Using Physical Activity Data

AI-driven sleep apnea screening with overnight blood oxygen saturation: current practices and future directions

Sleep apnea is one of the most common sleep disorders, which, if left untreated, may have severe health consequences in the long term. Many sleep apnea patients remain non-diagnosed due to lacking access to medical tests. In recent years, portable and wearable sensors that measure blood oxygen saturation (SpO2) are becoming common and affordable for daily use, and they open the door for affordable and accessible sleep apnea screening in the context of everyday life. To learn about the advancement in SpO2-based sleep apnea screening, we conducted a survey of published studies. We searched databases including Springer, Science Direct, Web of Science, ACM Digital Library, and IEEE Xplore using the keywords "sleep apnea" AND ("SpO2" OR "blood oxygen saturation") AND ("machine learning" OR "deep learning"). After screening 835 results, we included 31 publications for a full-text review. Analysis shows that SpO2-based sleep apnea screening studies consist of three main categories: (1) individual apnea events detection, (2) apnea-hypopnea index prediction, and (3) apnea severity classification. We found two significant research gaps: a lack of sufficient and diverse publicly available datasets, and the absence of standardized protocols for data collection, signal preprocessing, and model bench marking. Future research should focus on addressing these gaps to enhance the effectiveness and reliability of AI-driven sleep apnea screening methods using SpO2 signals.

Impact of comorbid sleep-disordered breathing on escitalopram treatment in patients newly diagnosed with generalized anxiety disorder: A 12-week prospective observational study

We aimed to evaluate the presence of sleep-disordered breathing (SDB) in generalized anxiety disorder (GAD) patients and its impacts after 12-week of escitalopram treatment. In this prospective observational study, GAD patients were followed up to determine whether comorbid SDB affects their treatment response. They underwent a home sleep apnea test (HSAT), and oxygen desaturation index ≥5 was considered indicative of SDB. All participants were treated with escitalopram 5 mg in the first 2 weeks and 10 mg in the remaining 10 weeks. They underwent assessments of heart rate variability and completed questionnaires for sleep, mood, attention, and daytime sleepiness on the day of enrollment, and 2 weeks, 4 weeks, and 12 weeks later. A total of 45 GAD participants (mean age, 56.2 years) were included in the study. Of these, 53.3% had comorbid SDB. Participants with GAD and SDB had higher baseline Beck Anxiety Inventory (BAI) and STOP-BANG scores. Both groups of participants with GAD showed overall improvement in anxiety, depression, and insomnia symptoms after 12 weeks of escitalopram treatment. Additionally, there were no statistically significant differences in the changes in BAI, Beck Depression Inventory, and Epworth Sleepiness Scale scores between the two groups at the Week 2, Week 4, and Week 12 assessments compared to baseline. However, the GAD group with comorbid SDB seemed to have a lower tendency for improvement in depressive symptoms than the group with non-comorbid SDB. Compared with the GAD group without comorbid SDB, the GAD group with comorbid SDB exhibited more severe anxiety symptoms at baseline and tended to show less improvement in depressive symptoms after 12 weeks of escitalopram treatment.

Mouth puffing phenomena of patients with obstructive sleep apnea when mouth-taped: device's efficacy confirmed with physical video observation

PURPOSE

This study aimed to design a device to monitor mouth puffing phenomena of patients with obstructive sleep apnea when mouth-taped and to employ video recording and computing algorithms to double-check and verify the efficacy of the device.

METHODS

A mouth puffing detector (MPD) was developed, and a video camera was set to record the patients' mouth puffing phenomena in order to make ensure the data obtained from the device was appropriate and valid. Ten patients were recruited and had polysomnography. A program written in Python was used to investigate the efficacy of the program's algorithms and the relationship between variables in polysomnography (sleep stage, apnea-hypopnea index or AHI, oxygen-related variables) and mouth puffing signals (MPSs). The video recording was used to validate the program. Bland-Altman plot, correlations, independent sample t-test, and ANOVA were analyzed by SPSS 24.0.

RESULTS

Patients were found to mouth puff when they sleep with their mouths taped. An MPD was able to detect the signals of mouth puffing. Mouth puffing signals were noted and categorized into four types of MPSs by our algorithms. MPSs were found to be significantly related to relative OSA indices. When all participants' data were divided into minutes, intermittent mouth puffing (IMP) was found to be significantly different from non-mouth puffing in AHI, oxygen desaturation index (ODI), and time of oxygen saturation under 90% (T90) (AHI: 0.75 vs. 0.31; ODI: 0.75 vs. 0.30; T90: 5.52 vs. 1.25; p < 0.001). Participants with severe OSA showed a higher IMP percentage compared to participants with mild to moderate OSA and the control group (severe: 38%, mild-to-moderate: 65%, control: 95%; p < 0.001).

CONCLUSIONS

This study established a simple way to detect mouth puffing phenomena when patients were mouth-taped during sleep, and the signals were classified into four types of MPSs. We propose that MPSs obtained from patients wearing the MPD can be used as a complement for clinicians to evaluate OSA.

Mouth Puffing Phenomenon and Upper Airway Features May Be Used to Predict the Severity of Obstructive Sleep Apnea

Purpose

This study aimed to investigate (1) the role of mouth puffing phenomenon and upper airway features in obstructive sleep apnea (OSA) and (2) whether mouth-taping during sleep alleviated the severity of OSA.

Participants and Methods

Seventy-one participants underwent a two-night home sleep test (the first day sleeping normally; the second day sleeping with their mouths being taped); their oximetry desaturation index (ODI) and mouth puffing signals (non-mouth puffing, complete mouth puffing, intermittent mouth puffing (IMP), and side mouth puffing) were detected by a validated fingertip pulse oximeter and a mouth puffing detector. The participants were grouped into the ODI-improved group and the ODI-not-improved group according to their sleeping test results. The radiograph was taken by cone-beam computed tomography and cephalometries. Upper airway features including airways, soft tissues, and oral cavity variables were measured.

Results

Participants with severe OSA showed a higher IMP percentage compared with those with normal, mild, and moderate OSA (severe: 33.78%, moderate: 22.38%, mild: 14.55%, normal: 0.31%, p < 0.001). In all participants, the ODI and the percentage of SpO₂ under 90 (T90) were positively related to body mass index (BMI) (r = 0.310 and 0.333, respectively), while ODI and T90 were negatively correlated with the minimum width of the airway (r = -0.473 and -0.474, respectively); all mentioned relationships were significant (p < 0.05).

Conclusion

IMP proportions were found to be higher in the half of participants whose ODI did not improve after mouth-taping and in those with severe OSA. Moreover, OSA patients with higher ODI, higher T90, and higher proportions of IMP were more likely to have a narrower upper airway.

Prevalence and effects of sleep-disordered breathing on middle-aged patients with sedative-free generalized anxiety disorder: A prospective case-control study

OBJECTIVE

Generalized anxiety disorder (GAD) and sleep-disordered breathing (SDB) share similar symptoms, such as poor sleep quality, irritability, and poor concentration during daily activities. This study aims to investigate the proportion of undiagnosed SDB and its impacts on anxiety severity and autonomic function in newly diagnosed, sedative-free GAD patients.

METHODS

This prospective case-control study included newly diagnosed GAD patients and control participants with matched age, sex, and body mass index (BMI) in Taiwan. All participants completed questionnaires for sleep and mood symptoms and a resting 5-min heart rate variability (HRV) examination during enrollment. The participants also used a home sleep apnea test to detect SDB. An oxygen desaturation index (ODI) ≥ 5 was considered indicative of SDB.

RESULTS

In total, 56 controls and 47 newly diagnosed GAD participants (mean age 55.31 ± 12.36 years, mean BMI 23.41 ± 3.42 kg/m²) were included. There was no significant difference in the proportion of undiagnosed SDB in the control and sedative-free GAD groups (46.43 vs. 51.06%). Sedative-free GAD patients with SDB scored significantly higher on Beck Anxiety Inventory (23.83 ± 11.54) than those without SDB (16.52 ± 10.61) (p < 0.001). Both control and sedative-free GAD groups with SDB had worse global autonomic function than the control group without SDB, as evidenced by the HRV results (p < 0.05 for all).

CONCLUSION

Average age 55 years and mean BMI 23 kg/m² patients with GAD and matched controls had an undiagnosed SDB prevalence of approximately 50%. SDB correlated with worsening anxiety severity and reduced cardiac autonomic function. Moreover, age and BMI were considered major risk factors for predicting undiagnosed SDB.