CES-EES Clinical Score and a Wearable Ring Sensor for Obstructive Sleep Apnea: Individual and Combined Validation Against In-Laboratory Polysomnography

Validation of Clinical Upper Airway Assessment Tool With Artificial Intelligence Wearable Technology Against In-Lab Polysomnography

This study evaluates whether a clinical upper airway assessment tool (the Clinical Examination Score plus ENT Examination Score, CES-EES) and an artificial-intelligence wearable ring (Belun Ring, Belun Sleep System BLS-100) can serve as accurate, less resource-intensive alternatives to in-lab polysomnography (PSG) for diagnosing obstructive sleep apnea (OSA). Adults referred to the Otorhinolaryngology sleep clinic at Universiti Malaya Medical Centre (UMMC) for suspected OSA, who score 4 or more on the combined CES-EES scale, undergo a single overnight Level 1 in-lab PSG. The Belun Ring is worn concurrently with standard PSG electrodes during this same overnight study. The apnea-hypopnea index (AHI) from the Belun Ring and the CES-EES score, individually and in combination, are compared against the AHI from in-lab PSG -- the diagnostic reference standard -- to assess their agreement, correlation, and diagnostic accuracy for OSA.

Study Overview

• Status: Recruiting
• Conditions: Obstructive Sleep Apnea
• Intervention / Treatment: Device: Belun Ring (Belun Sleep System BLS-100); Other: CES-EES Clinical Scoring

Detailed Description

Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder associated with cardiovascular, cerebrovascular, and other long-term health consequences if untreated. In-lab polysomnography (PSG) is the diagnostic reference standard but is resource-intensive, costly, and associated with long waiting times. Existing screening tools such as the STOP-BANG questionnaire and the Epworth Sleepiness Scale (ESS) have recognized sensitivity/specificity trade-offs. The Clinical Examination Score (CES) combined with the ENT Examination Score (EES) is a previously described clinical scoring tool for OSA screening. The Belun Ring (Belun Sleep System BLS-100) is an FDA 510(k)-cleared (Class II), Malaysia Medical Device Authority-registered, AI/deep-learning-facilitated wearable capable of estimating AHI, sleep staging, and OSA severity.

This is a prospective, comparative, single-centre study conducted at Universiti Malaya Medical Centre (UMMC). Adults referred to the Otorhinolaryngology sleep clinic for suspected OSA, with high ESS and/or STOP-BANG scores, are screened with the CES-EES; those scoring 4 or more and otherwise meeting eligibility criteria are enrolled. After informed consent, participants undergo a standardised history, demographic data collection, and physical examination (oral cavity examination, flexible nasopharyngeal endoscopy, dental assessment), followed by a single overnight Level 1 in-lab PSG (Compumedics, 7-channel) at the UMMC Neurology Sleep Lab. The Belun Ring is fitted to the participant's index finger concurrently with standard PSG electrodes, so both devices record simultaneously during the same overnight study. A minimum of 4 hours total sleep time (TST) is required; participants with less than 4 hours TST are excluded from analysis. Both PSG and Belun Ring AHI are scored using AASM 1A criteria (hypopnea defined by desaturation of 3% or more). PSG is manually scored by a sleep technician; Belun Ring output is processed by the device's AI algorithm and independently cross-checked by two investigators.

The primary comparisons are: (1) CES-EES score against PSG AHI; (2) Belun Ring AHI against PSG AHI; and (3) CES-EES combined with Belun Ring AHI against PSG AHI. Planned statistical analyses include the paired t-test or Wilcoxon signed-rank test for comparative analysis, Bland-Altman plots for agreement/bias analysis, the intraclass correlation coefficient (ICC) for inter-scorer reliability, and descriptive statistics (mean, median, SD, range).

• Study Type: Observational
• Enrollment (Estimated): 58

Contacts and Locations

• Study Contact: Name: Dr. Kugan a/l Varatha Raju, MD; Phone Number: +6012-4559957; Email: kugan.varatha@ummc.edu.my
• Study Contact Backup: Name: Associate Professor Dr. Goh Liang Chye, MBBS; Email: gohlc@ummc.edu.my

Study Locations

• Malaysia
  • Kuala Lumpur
    • Pantai Valley, Kuala Lumpur, Malaysia, 59100
      • Recruiting
      • Universiti Malaya Medical Centre (UMMC)
      • Principal Investigator: Varatha Raju Kugan, MD
      • Sub-Investigator: Liang Chye Goh, MBBS
      • Sub-Investigator: Kheng Seng Lim, MBBS

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Adults referred to the UMMC Otorhinolaryngology sleep clinic for sleep-related breathing disorders and scheduled for in-lab PSG

Description

Inclusion Criteria:

• ≥18 years old
• Patients with suspected OSA (high ESS and/or STOP-BANG score)
• CES-EES score 4 or more
• Newly diagnosed cases
• Minimum 4 hours of Total Sleep Time (TST)

Exclusion Criteria:

• Active URTI (upper respiratory tract infection) in the past 1 month
• Current smoker
• Alcohol consumption within 8 hours prior to testing
• History of head and neck carcinoma
• Active respiratory or neurological disorders
• Active psychiatric disorders and currently on psychiatric medication

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Adults with suspected OSA undergoing concurrent CES-EES scoring, Belun Ring monitoring, and in-lab P; Adults with suspected OSA undergoing concurrent CES-EES scoring, Belun Ring monitoring, and in-lab PSG

Device: Belun Ring (Belun Sleep System BLS-100); AI/deep-learning-facilitated wearable ring worn on the index finger concurrently with standard PSG electrodes during the overnight PSG study; estimates AHI, sleep stages, and OSA severity using AASM 1A scoring criteria (desaturation of 3% or more defines hypopnea).; Other: CES-EES Clinical Scoring; Combined Clinical Examination Score (CES) and ENT Examination Score (EES), administered via history, oral cavity examination, flexible nasopharyngeal endoscopy, and dental assessment prior to PSG.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Apnea-Hypopnea Index (AHI)	AHI (events/hour) derived from polysomnogram or wearable sleep study, scored using AASM 1A criteria (desaturation of 3% or more defines hypopnea); output cross-checked by two independent investigators.	Baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Sleep quality parameters	Total sleep time (TST), sleep latency, wake after sleep onset (WASO), sleep efficiency, and lowest oxygen saturation (LSAT)	Baseline
Epworth Sleepiness Scale (ESS) score	Self-reported daytime sleepiness questionnaire	Baseline

Collaborators and Investigators

• Sponsor: University of Malaya
• Collaborators: Belun Technology Company Limited
• Investigators: Principal Investigator: Varatha Raju Kugan, MD, Department of Otorhinolaryngology, Head & Neck Surgery, Universiti Malaya Medical Centre

Publications and helpful links

General Publications

• Chung F, Yegneswaran B, Liao P, Chung SA, Vairavanathan S, Islam S, Khajehdehi A, Shapiro CM. STOP questionnaire: a tool to screen patients for obstructive sleep apnea. Anesthesiology. 2008 May;108(5):812-21. doi: 10.1097/ALN.0b013e31816d83e4.
• Johns MW. A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep. 1991 Dec;14(6):540-5. doi: 10.1093/sleep/14.6.540.
• Gottlieb DJ, Punjabi NM. Diagnosis and Management of Obstructive Sleep Apnea: A Review. JAMA. 2020 Apr 14;323(14):1389-1400. doi: 10.1001/jama.2020.3514.
• Strumpf Z, Gu W, Tsai CW, Chen PL, Yeh E, Leung L, Cheung C, Wu IC, Strohl KP, Tsai T, Folz RJ, Chiang AA. Belun Ring (Belun Sleep System BLS-100): Deep learning-facilitated wearable enables obstructive sleep apnea detection, apnea severity categorization, and sleep stage classification in patients suspected of obstructive sleep apnea. Sleep Health. 2023 Aug;9(4):430-440. doi: 10.1016/j.sleh.2023.05.001. Epub 2023 Jun 26.
• 6. Hasan KIB, Lim KS, Goh LC, Fong SL, Ramanaidu LP, Lee ZY, Tan CT. Sequential screenings improve prediction in obstructive sleep apnoea severity. Neurology Asia. 2025;30(2):571-585.
• 1. American Academy of Sleep Medicine. International Classification of Sleep Disorders. 3rd ed. Darien, IL: American Academy of Sleep Medicine; 2014.

Study record dates

Study Major Dates

• Study Start (Actual): March 1, 2026
• Primary Completion (Estimated): March 1, 2027
• Study Completion (Estimated): March 1, 2027

Study Registration Dates

• First Submitted: August 16, 2026
• First Submitted That Met QC Criteria: August 21, 2026
• First Posted (Actual): August 25, 2026

Study Record Updates

• Last Update Posted (Actual): August 25, 2026
• Last Update Submitted That Met QC Criteria: August 21, 2026
• Last Verified: August 1, 2026

More Information

Terms related to this study

• Keywords: polysomnography; diagnostic accuracy; obstructive sleep apnea; wearable device; sleep parameters
• Additional Relevant MeSH Terms: Nervous System Diseases; Respiratory Tract Diseases; Respiration Disorders; Sleep Wake Disorders; Apnea; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Apnea Syndromes; Sleep Apnea, Obstructive
• Other Study ID Numbers: UMMC-MREC 202583-15424

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: No