An interim oral appliance as a screening tool during drug-induced sleep endoscopy to predict treatment success with a mandibular advancement device for obstructive sleep apnea.

PURPOSE: Previous studies have shown a wide range of efficacy (29 to 71%) of a mandibular advancement device (MAD) in the treatment of obstructive sleep apnea (OSA). Currently, the ability to preselect suitable patients for MAD therapy based on individual characteristics related to upper airway collapsibility is limited. We investigated if the use of non-custom interim MAD during drug-induced sleep endoscopy (DISE) could be a valuable screening tool to predict MAD treatment outcome. METHODS: In a single-center prospective study including a consecutive series of patients with OSA, we compared DISE outcomes with a MAD in situ with polysomnography results after 3 months of using the same MAD that was used during DISE. RESULTS: Of 41 patients who completed the study, the median apnea-hypopnea index (AHI) was 16.0 events/h [IQR 7.4-23.4]. Respiratory outcomes on polysomnography, including apnea index (AI), total AHI, AHI in supine position, and oxygen desaturation index, all significantly improved after 3 months of MAD treatment. With complete improvement of the upper airway obstruction with the MAD in situ during DISE in supine position, patients were 6.3 times more likely to be a responder to MAD treatment compared to patients with a persisting complete obstruction, although not statistically significant (OR 6.3; 95%CI 0.9-42.7; p = 0.060). CONCLUSION: The potential predictive value with regard to MAD therapy outcomes of the use of an interim MAD during DISE would be an important finding, since the prediction of MAD therapy outcome is of great clinical and scientific interest. A study with a larger cohort should be performed to further investigate our findings.

Do dental parameters predict severity of obstructive sleep apnea and mandibular advancement device therapy outcomes? A pilot study.

BACKGROUND: Mandibular Advancement Devices (MAD's) are oral appliances commonly used in treatment of Obstructive Sleep Apnea (OSA). OSA severity and certain other factors, such as BMI and neck circumference, correlate with MAD therapy success. So far, the predictive value of dental parameters, such as dental profile, molar-classification, overjet, overbite, maximal retrusion, maximal protrusion and protrusive range, has not been fully investigated. OBJECTIVES: We aimed to investigate whether dental parameters influence OSA severity and MAD therapy outcome and could therefore be helpful in phenotyping OSA patients. Furthermore, we studied the predictive power of dental parameters for OSA severity and successful MAD therapy. We hypothesise that specific dental parameters correlate with more severe OSA and with more successful MAD treatment. METHODS: We performed a cohort study, including OSA patients diagnosed by polysomnography (PSG). Dental parameters were collected. Objective treatment outcome was collected by performing a PSG with MAD after three months of therapy. Differences between OSA severity groups and MAD treatment outcomes were analysed and dental parameters were correlated between groups. RESULTS: The relation between dental parameters and OSA severity was analysed in 143 patients, fifty patients had a PSG with MAD in situ after a 3-month therapy. The median baseline Apnea Hypopnea Index (AHI) significantly reduced from 17.6 (8.7-29.3) to 11.1 (5.5-17.5). Overbite and maximal retrusion differed significantly between mild, moderate and severe OSA. Other dental parameters did not differ significantly between the groups, nor correlated with OSA severity or MAD treatment outcome. CONCLUSION: In this study, no correlation between dental parameters and OSA severity or MAD treatment outcomes was found. Therefore, screening patients for OSA and MAD treatment outcome based on dental parameters is currently not possible.

Position-dependent obstructive sleep apnea and its influence on treatment success of mandibular advancement devices.

PURPOSE: Depending on the severity of pre-treatment obstructive sleep apnea (OSA) and the criteria used to define treatment success, the efficacy of mandibular advancement devices (MADs) ranges from 30 to 69%. Identifying suitable candidates is the key to increasing the efficacy of a MAD. Positive predictors include a low body mass index, a low apnea-hypopnea index (AHI), and low age. Another consideration is whether or not a patient's OSA is position dependent. To evaluate the effect of such dependency on MAD treatment success, we studied the following: treatment success across the patient's total AHI and in the supine and non-supine sleeping positions; the influence of pre-treatment position dependency on MAD treatment success; and the effect of MAD treatment on post-treatment shifts in position dependency. METHODS: This is a single-center retrospective study of patients with OSA. Patients were diagnosed through an overnight polysomnography and treated with a MAD between February 2015 and January 2018. They were defined as being positional if the AHI in supine sleeping position was at least twice as high as in the non-supine position. RESULTS: Complete treatment success was achieved in 32% of study population (n = 96) and partial success in 54%. Complete treatment success was significantly higher (p = 0.004) when a patient was sleeping in the non-supine position. Treatment success did not differ significantly between patients who were position dependent and those who were not. When treated with a MAD, patients did not spend significantly more time in supine position. Neither did we find any post-treatment shifts in position dependency. CONCLUSION: A MAD is an effective treatment modality that may significantly reduce the total AHI, supine, and non-supine AHI. Since position dependency has no impact on MAD treatment success, it does not determine whether or not a patient is a suitable candidate for MAD treatment.

Daytime polysomnography to perform titration for upper airway stimulation in patients with obstructive sleep apnea.

PURPOSE: Upper airway stimulation (UAS) is an innovative treatment for patients with obstructive sleep apnea (OSA). UAS titrations are performed 3 months after activation of the device to optimize its effectiveness. In general, these titrations are performed during an in-laboratory overnight polysomnography (PSG). However, overnight titrations are expensive and can be logistically challenging because they are labor-intensive which causes shortage of sleep technicians available for night shifts. In addition, recently, overnight PSGs were postponed and canceled due to the COVID-19 pandemic. We aimed to assess the feasibility of a daytime PSG to perform titration of UAS therapy as an alternative for a conventional overnight PSG. METHODS: We performed a prospective single-center observational cohort study. Patients were included when planned for UAS titration; this was approximately 6 months after UAS activation. Data on sleep architecture, patient experience, and respiratory outcomes were collected to evaluate the feasibility. An overnight follow-up PSG 12 months after implantation was used to compare sleep architecture and therapy response. RESULTS: Of 23 patients, four were excluded from analysis because of technical issues during PSG. Even though patients slept significantly shorter during the daytime PSG, this was enough time to complete the titration successfully with 30-min sleep in final therapeutic settings in 84% of the patients. Patients (94%) had a positive experience with the daytime titration. Respiratory outcomes were significantly reduced during titration and were maintained at the 12-month follow-up. CONCLUSION: Daytime titrations are a valuable alternative for conventional overnight titrations. Our findings suggest the implementation of daytime titrations as standard of care. This will contribute to easier logistics and better work circumstances for sleep technicians without jeopardizing titration quality.

The effect of postoperative CPAP use on anastomotic and staple line leakage after bariatric surgery.

PURPOSE: Almost two-thirds of the population undergoing bariatric surgery (BS) suffers from obstructive sleep apnea (OSA). Continuous positive airway pressure (CPAP) is the standard treatment for moderate to severe OSA and is recommended in patients undergoing BS perioperatively. A severe and dreaded complication after BS is anastomotic leakage. There is theoretical concern that perioperative CPAP use may result in increased distension of the gastrointestinal tract and increase the risk of developing an anastomotic leakage. The aim of this study was to evaluate the effect of postoperative CPAP use on the risk of developing anastomotic leakages after BS. METHODS: Retrospectively, all patients from a single bariatric center who underwent BS from November 2007 to August 2019 were included. Presence and severity of OSA were determined using poly(somno)graphy. To evaluate the effect of postoperative CPAP use on anastomotic leakage, a multivariable logistic regression analysis was performed. RESULTS: A total of 4052 patients were included, with OSA being diagnosed in 62%. Overall, 970 patients (24%) used CPAP after BS. Anastomotic leakage occurred in 64 (1.6%) patients after BS. Leakage rate was 1.3% in non-CPAP group versus 2.5% in CPAP group (p = 0.01). CPAP use was associated with anastomotic leakage; however, after adjustment, CPAP use was not an independent predictor (OR = 1.40, 95% CI 0.60-3.28, p = 0.44). CONCLUSION: There is no independent relation between postoperative CPAP use and anastomotic leakage after BS. Only revision surgery was an independent predictor of anastomotic leakage.

Is there still a role for nuchal translucency measurement in the changing paradigm of first trimester screening?

OBJECTIVES: To give an overview of the genetic and structural abnormalities occurring in fetuses with nuchal translucency (NT) measurement exceeding the 95th percentile at first-trimester screening and to investigate which of these abnormalities would be missed if cell-free fetal DNA (cfDNA) were used as a first-tier screening test for chromosomal abnormalities. METHODS: This is a national study including 1901 pregnancies with NT≥95th percentile referred to seven university hospitals in the Netherlands between 1 January 2010 and 1 January 2016. All cases with unknown pregnancy outcome were excluded. Results of detailed ultrasound examinations, karyotyping, genotyping, pregnancy and neonatal outcomes, investigation by a clinical geneticist and post-mortem investigations were collected. RESULTS: In total, 821 (43%) pregnancies had at least one abnormality. The rate of abnormalities was 21% for fetuses with NT between 95th and 99th percentile and 62% for fetuses with NT≥99th percentile. Prevalence of single-gene disorders, submicroscopic, chromosomal and structural abnormalities was 2%, 2%, 30% and 9%, respectively. CONCLUSION: Although cfDNA is superior to the combined test, especially for the detection of trisomy 21, 34% of the congenital abnormalities occurring in fetuses with increased NT may remain undetected in the first trimester of pregnancy, unless cfDNA is used in combination with fetal sonographic assessment, including NT measurement.

Using standardized ultrasound imaging to correlate OSA severity with tongue morphology.

BACKGROUND: Ultrasound imaging has been explored as a potential diagnostic tool for obstructive sleep apnea (OSA); we reported backscatter ultrasound imaging (BUI) of the tongue correlates with OSA severity in adults. We focus on anatomical features of the tongue using standardized ultrasonography and hypothesize that differences in morphology correlate with OSA severity. METHODS: This prospective study was IRB approved (53,172) and conducted at Stanford University Sleep Surgery Clinic. Patients ≥18 years with polysomnography (PSG) underwent a standardized submental ultrasound scan using a laser alignment tool to observe the upper airway in supine position during tidal respiration. Images acquired from this scan were divided into 4 equiangular regions (A-D). RESULTS: A total of 144 patients (30 women) July 2020-December 2022 were included with mean age 41.6 years (±12.9 SD), BMI 27.2 kg/m2(±4.7 SD), and AHI 19.7 (±20.0 SD). Moderate-to-severe OSA patients had significantly narrower airspace at regions A, B and C with p-values ranging from <0.0001 to 0.0003. These patients had a significantly wider (p = 0.0021-0.0045 for regions A, B and C) tongue and thicker (p = 0.0403 for region B) deep tissue. The predictive model to assess the risk of moderate-to-severe OSA achieved an area under the receiver operating characteristic curve of 0.839 (95 % CI: 0.769 to 0.895). CONCLUSIONS: With standardized, computerized ultrasound imaging of the shape and configuration of the tongue, we identified regions that correlated well with OSA severity. Further research is needed to determine the clinical implications of such pathophysiological findings.

Age-specific and family-centered information modalities to prepare children at home for day-care surgery.

BACKGROUND: Surgery induced stress and anxiety in children and parents can be reduced by providing preoperative information adapted to their needs. Aim of this study was to evaluate the effects of three different information modalities (coloring page, mobile application and videos) to prepare children and their parents for day-care surgery on preoperative anxiety and postoperative pain experienced by the child, and preoperative anxiety and satisfaction of parents. METHODS: Prospective observational study including children and their parents that were offered specifically developed information modalities to prepare for day-care surgery. Results were compared between children and their parents that used none (i.e., control group) versus one or more information modalities (i.e., intervention group). Primary outcomes were preoperative anxiety measured using PROMIS v2.0 Anxiety and postoperative pain in children. Secondary outcomes were preoperative parental anxiety (STAI questionnaire) and family satisfaction with information and communication (modified PedsQL Healthcare Satisfaction questionnaire). Subgroup analyses were performed between preschoolers (0-5 years) and school-aged (≥5) children. RESULTS: 93 patients (male 53%) were included in the intervention (n=56) and control group (n=37). Levels of children's preoperative anxiety and postoperative pain, and parental anxiety did not differ between both groups. Families of prepared children were more satisfied with information and communication about preoperative surgical information (8 vs. 6.6, p=0.004) and satisfaction with how parents (7 vs 8, p=0.019) and children (8 vs 6, p=0.018) were prepared for surgery. CONCLUSIONS: Preoperative anxiety did not differ between prepared and unprepared children. The use of specifically developed family-centered and age-appropriate information modalities to prepare children for day-care surgery at home results in superior family satisfaction. LEVEL OF EVIDENCE: III.

Association of Backscattered Ultrasonographic Imaging of the Tongue With Severity of Obstructive Sleep Apnea in Adults.

Importance: Determining interventions to manage obstructive sleep apnea (OSA) depends on clinical examination, polysomnography (PSG) results, and imaging analysis. There remains the need of a noninvasive and cost-effective way to correlate relevant upper airway anatomy with severity of OSA to direct treatment and optimize outcome. Objective: To determine whether backscattered ultrasonographic imaging (BUI) analysis of the tongue is associated with severity of OSA in adults. Design, Setting, and Participants: In this prospective, single-center, diagnostic study of a consecutive series of patients (aged ≥18 years) at a sleep surgery clinic, the 89 included patients had a PSG within 3 years at the time of ultrasonography and BUI analysis between July 2020 and March 2022. Patients were excluded if body mass index had changed more than 10% since time of PSG. A standardized submental ultrasonographic scan with laser alignment was used with B-mode and BUI analysis applied to the tongue. The B-mode and BUI intensity were associated with the apnea-hypopnea index (AHI), a measure of severity of apnea from normal (no OSA) to severe OSA. Exposures: Ultrasonography and PSG. Main Outcomes and Measures: The main outcomes were BUI parameters and their association with AHI value. Results: Eighty-nine patients were included between July 2020 and March 2022. A total of 70 (78.7%) male patients were included; and distribution by race and ethnicity was 46 (52%) White participants, 22 (25%) Asian participants, and 2 (2%) African American participants, and 19 (21%) others. Median (IQR) age was 37.0 (29.0-48.3) years; median (IQR) BMI was 25.3 (23.2-29.8); and median (IQR) AHI was 11.1 (5.6-23.1) events per hour. At the middle to posterior tongue region, the 4 OSA severity levels explained a significant portion of the BUI variance (η2 = 0.153-0.236), and a significant difference in BUI values was found between the subgroups with AHI values of less than 15 (no OSA and mild OSA) and greater than or equal to 15 (moderate OSA and severe OSA) events per hour. The echo intensity showed no significant differences. The BUI values showed a positive association with AHI, with a Spearman correlation coefficient of up to 0.43. Higher BUI values remained associated with higher AHI after correction for the covariates of BMI and age. Conclusions and Relevance: In this prospective diagnostic study, standardized BUI analysis of the tongue was associated with OSA severity. With the practicality of ultrasonography, this analysis is pivotal in connecting anatomy with physiology in treatment planning for patients with OSA.

International Consensus Statement on Obstructive Sleep Apnea.

BACKGROUND: Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA). METHODS: Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus. RESULTS: The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated. CONCLUSION: This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

Similar effect of hypoglossal nerve stimulation for obstructive sleep apnea in 5 disease severity categories.

STUDY OBJECTIVES: Data on adherence and outcome of upper airway stimulation (UAS) for patients with obstructive sleep apnea (OSA) are collected in an international registry (ADHERE). Previous publications report significant improvement in self-reported and objective OSA outcomes, durable effectiveness, and high adherence. Debate remains whether the effectiveness of UAS is influenced by preoperative OSA severity; therefore, we aimed to evaluate this using data from the ADHERE Registry. METHODS: ADHERE is a postmarket, ongoing, international multicenter registry. Adult patients were included if they had undergone UAS implantation and had at least 1 follow-up visit recorded in the database on June 8, 2021. We divided the patients into 5 subgroups, based on OSA severity at baseline (AHI in events/h): subgroup 1 (0-15), 2 (15-30), 3 (≥ 30-50), 4 (> 50-65), and 5 (> 65). We compared results regarding objective and self-reported treatment outcomes. RESULTS: A total of 1,963 patients were included. Twelve months after implantation, there was a significant (P < .0001) improvement in objective sleep parameters in all subgroups with an AHI above 15 events/h. Patients in subgroup 1 had the lowest AHI at the final visit and the AHI reduction in patients in subgroup 5 was the largest (P < .0001). No significant difference was found between the subgroups in overall treatment success (66.6%) and improvement in self-reported outcomes. CONCLUSIONS: Our results suggest that UAS is an effective treatment for patients with an AHI ≥ 15 events/h, independent of preoperative OSA severity. Self-reported outcomes and treatment success did not differ significantly between the 5 subgroups. These results clearly support that the indication of UAS could be broadened for patients with an AHI above 65 events/h, which, to date, is not common practice. CLINICAL TRIAL REGISTRATION: Registry: ClinicalTrials.gov; Title: Adherence and Outcome of Upper Airway Stimulation (UAS) for OSA International Registry (ADHERE Registry); Identifier: NCT02907398; URL: https://www.clinicaltrials.gov/ct2/show/NCT02907398. CITATION: Bosschieter PFN, de Vries N, Mehra R, et al. Similar effect of hypoglossal nerve stimulation for obstructive sleep apnea in 5 disease severity categories. J Clin Sleep Med. 2022;18(6):1657-1665.

Evaluation of drug-induced sleep endoscopy as a tool for selecting patients with obstructive sleep apnea for maxillomandibular advancement.

STUDY OBJECTIVES: (1) To investigate if drug-induced sleep endoscopy (DISE) findings are predictive of surgical response for patients undergoing maxillomandibular advancement (MMA) for obstructive sleep apnea (OSA) and (2) to investigate the predictive value of the jaw thrust maneuver during DISE in terms of surgical response to MMA. METHODS: A retrospective cohort study was conducted in patients with OSA who underwent a baseline polysomnography (PSG) and DISE followed by MMA and a 3- to 6-month follow-up PSG between September 1, 2011, and September 30, 2020. RESULTS: Sixty-four patients with OSA (50 males [78.1%]; mean ± SD age = 51.7 ± 9.5 years; mean ± SD apnea-hypopnea index = 49.0 ± 20.8 events/h) were included. Thirty-nine patients were responders, and 25 were nonresponders. Adjusting for baseline characteristics and surgical characteristics (eg, age, baseline apnea-hypopnea index, degree of maxillary advancement), patients with complete anteroposterior epiglottic collapse had 0.239 times lower odds for response to MMA (95% confidence interval, 0.059-0.979; P = .047). No significant relationship was found between complete concentric velum collapse and MMA response. There was no statistically significant association between effect of jaw thrust maneuver during DISE on upper airway patency and treatment outcome of MMA. CONCLUSIONS: This study indicates that DISE is a promising tool to identify patients who will or will not respond to MMA for treating OSA. Patients with complete anteroposterior epiglottic collapse may be less suitable candidates for MMA. CITATION: Zhou N, Ho J-PTF, de Vries N, Bosschieter PFN, Ravesloot MJL, de Lange J. Evaluation of drug-induced sleep endoscopy as a tool for selecting patients with obstructive sleep apnea for maxillomandibular advancement. J Clin Sleep Med. 2022;18(4):1073-1081.

Equal effect of a noncustom vs a custom mandibular advancement device in treatment of obstructive sleep apnea.

STUDY OBJECTIVES: Numerous types of mandibular advancement devices (MADs) are available to treat patients with obstructive sleep apnea, varying from noncustom to custom devices. Only a limited number of studies have been performed to determine whether a noncustom MAD could be used to predict treatment success of a custom MAD. In this study, we investigated the potential of a new-generation noncustom MAD, by comparing its effectiveness with a custom MAD. We hypothesized that the effectiveness of the devices is similar with regard to both objective (polysomnography) and self-reported (questionnaires, adherence, and patient satisfaction) outcomes. METHODS: This was a single-center prospective randomized crossover study including a consecutive series of patients with obstructive sleep apnea. Patients were randomized to start either with the noncustom or custom MAD. Both MADs were applied for 12 weeks, followed by polysomnography with MAD in situ and questionnaires. After the first 12 weeks of follow-up, a washout period of 1 week was applied. Equal effectiveness was defined as no significant differences in both objective and self-reported outcomes between both devices. RESULTS: Fifty-eight patients were included; 40 completed the full follow-up. The median apnea-hypopnea index significantly decreased from 16.3 (7.7, 24.8) events/h to 10.7 (5.6, 16.6) events/h with the custom MAD (P = .010) and to 7.8 (2.9, 16.1) events/h with the noncustom MAD (P < .001). Self-reported outcomes significantly improved in both groups. No significant differences were found between both devices. CONCLUSIONS: The effectiveness of a noncustom and custom MAD is comparable, which suggests that a noncustom MAD can be used as a selection tool for MAD treatment eligibility to improve MAD treatment outcome. CLINICAL TRIAL REGISTRATION: Registry: Netherlands Trial Register; Name: The Use of a Boil and Bite Mandibular Advancement Device vs a Custom Mandibular Advancement Device in Obstructive Sleep Apnea Management; URL: https://www.trialregister.nl/trial/7249; Identifier: NL64738.100.18. CITATION: Bosschieter PFN, Uniken Venema JAM, Vonk PE, et al. Equal effect of a noncustom vs a custom mandibular advancement device in treatment of obstructive sleep apnea. J Clin Sleep Med. 2022;18(9):2155-2165.

Predicting upper airway collapse sites found in drug-induced sleep endoscopy from clinical data and snoring sounds in patients with obstructive sleep apnea: a prospective clinical study.

STUDY OBJECTIVES: The primary aim was to predict upper airway collapse sites found in drug-induced sleep endoscopy (DISE) from demographic, anthropometric, clinical examination, sleep study, and snoring sound parameters in patients with obstructive sleep apnea (OSA). The secondary aim was to identify the above-mentioned parameters that are associated with complete concentric collapse of the soft palate. METHODS: All patients with OSA who underwent DISE and simultaneous snoring sound recording were enrolled in this study. Demographic, anthropometric, clinical examination (viz., modified Mallampati classification and Friedman tonsil classification), and sleep study parameters were extracted from the polysomnography and DISE reports. Snoring sound parameters during DISE were calculated. RESULTS: One hundred and nineteen patients with OSA (79.8% men; age = 48.1 ± 12.4 years) were included. Increased body mass index was found to be associated with higher probability of oropharyngeal collapse (P < .01; odds ratio = 1.29). Patients with a high Friedman tonsil score were less likely to have tongue base collapse (P < .01; odd ratio = 0.12) and epiglottic collapse (P = .01; odds ratio = 0.20) than those with a low score. A longer duration of snoring events (P = .05; odds ratio = 2.99) was associated with a higher probability of complete concentric collapse of the soft palate. CONCLUSIONS: Within the current patient profile and approach, given that only a limited number of predictors were identified, it does not seem feasible to predict upper airway collapse sites found in DISE from demographic, anthropometric, clinical examination, sleep study, and snoring sound parameters in patients with OSA. CITATION: Huang Z, Bosschieter PFN, Aarab G, et al. Predicting upper airway collapse sites found in drug-induced sleep endoscopy from clinical data and snoring sounds in obstructive sleep apnea patients: a prospective clinical study. J Clin Sleep Med. 2022;18(9):2119-2131.

Prediction of the obstruction sites in the upper airway in sleep-disordered breathing based on snoring sound parameters: a systematic review.

BACKGROUND: Identification of the obstruction site in the upper airway may help in treatment selection for patients with sleep-disordered breathing. Because of limitations of existing techniques, there is a continuous search for more feasible methods. Snoring sound parameters were hypothesized to be potential predictors of the obstruction site. Therefore, this review aims to i) investigate the association between snoring sound parameters and the obstruction sites; and ii) analyze the methodology of reported prediction models of the obstruction sites. METHODS: The literature search was conducted in PubMed, Embase.com, CENTRAL, Web of Science, and Scopus in collaboration with a medical librarian. Studies were eligible if they investigated the associations between snoring sound parameters and the obstruction sites, and/or reported prediction models of the obstruction sites based on snoring sound. RESULTS: Of the 1016 retrieved references, 28 eligible studies were included. It was found that the characteristic frequency components generated from lower-level obstructions of the upper airway were higher than those generated from upper-level obstructions. Prediction models were built mainly based on snoring sound parameters in frequency domain. The reported accuracies ranged from 60.4% to 92.2%. CONCLUSIONS: Available evidence points toward associations between the snoring sound parameters in the frequency domain and the obstruction sites in the upper airway. It is promising to build a prediction model of the obstruction sites based on snoring sound parameters and participant characteristics, but so far snoring sound analysis does not seem to be a viable diagnostic modality for treatment selection.