Clinical Investigation to Observe the Long-term Safety and Efficacy of the Digital Medical Device 'BELL-001' in Patients Diagnosed With Insomnia

A Multicenter, Single-arm, Prospective Clinical Investigation to Observe the Long-term Safety and Efficacy of the Digital Medical Device 'BELL-001' in Patients Diagnosed With Insomnia

This study is a multicenter, single-arm, prospective clinical trial designed to observe the long-term safety and effectiveness of the digital medical device BELL-001 in patients diagnosed with insomnia. Insomnia is a common sleep disorder that can significantly affect daytime functioning, mood, and overall quality of life. Many patients continue to experience difficulties despite lifestyle modifications or pharmacological treatment, and there is a growing need for safer, non-pharmacological therapeutic options.

BELL-001 is a smartphone-based therapeutic device that delivers personalized auditory stimulation during the pre-sleep period. The device is designed to promote relaxation and support the transition into sleep by analyzing individual breathing patterns and providing synchronized sound feedback. This study evaluates the long-term safety and effectiveness of BELL-001 over approximately 3 months (12 weeks) of use.

Forty adults diagnosed with insomnia will participate as the BELL-001 group. Participants will use the device for 12 weeks. During the study period, insomnia severity, depression, anxiety, and work productivity will be assessed. The outcome measures include changes in the Insomnia Severity Index (ISI), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), and Work Productivity and Activity Impairment Questionnaire (WPAI) at 4, 8, and 12 weeks compared to baseline; changes in Total Sleep Time (TST), Sleep Onset Latency (SOL), Wake After Sleep Onset (WASO), and sleep stage ratios measured via Nearable Device at 4, 8, and 12 weeks; and changes in subjective Sleep Latency (sSL), subjective Sleep Quality (sSQ), subjective Wake After Sleep Onset (sWASO), subjective number of awakenings after sleep onset, subjective Sleep Efficiency (sSE), and subjective Total Sleep Time (sTST) assessed through sleep diaries at 4, 8, and 12 weeks compared to baseline. Safety will be evaluated over the 12-week period. Additional outcome measures will include assessment of compliance and satisfaction.

This clinical trial is conducted at multiple hospitals in Korea and adheres to ethical guidelines, including review and approval by Institutional Review Boards (IRBs). Participation is voluntary, and all individuals will provide informed consent prior to the initiation of any study procedures. The results of this study are expected to provide key evidence for the clinical application of a digital, non-pharmacological intervention for adults with insomnia.

Study Overview

• Status: Not yet recruiting
• Conditions: Insomnia; Sleep Initiation and Maintenance Disorders
• Intervention / Treatment: Device: BELL-001 Digital Therapeutic

Detailed Description

Insomnia is a highly prevalent sleep disorder characterized by persistent difficulty with initiating or maintaining sleep, accompanied by daytime impairment such as fatigue, reduced concentration, mood disturbance, and decreased overall functioning. Despite the availability of pharmacologic options and behavioral approaches such as cognitive behavioral therapy for insomnia (CBT-I), many patients experience limited access, inadequate treatment response, concerns about long-term medication dependence, or poor adherence to structured behavioral interventions. As a result, there remains a significant clinical need for safe, accessible, non-pharmacological therapies that can effectively address the underlying physiological and psychological factors contributing to insomnia.

BELL-001 is a novel digital therapeutic device designed to modulate pre-sleep physiological arousal through personalized auditory stimulation synchronized to an individual's respiratory rhythm. Pre-sleep hyperarousal, including elevated autonomic activation and persistent cognitive and somatic tension, is recognized as a central mechanism in chronic insomnia. BELL-001 analyzes the user's natural breathing pattern through the smartphone microphone and generates real-time auditory feedback aligned with the respiratory phase. This feedback aims to stabilize breathing rhythms, promote parasympathetic activation, reduce sympathetic hyperarousal, and facilitate the transition from wakefulness to sleep. The therapeutic approach is grounded in neurophysiological principles related to interoception, vagal tone modulation, and auditory-respiratory entrainment. Preliminary feasibility and pilot results, including studies conducted at Seoul National University Hospital and Harvard-affiliated centers, suggest that BELL-001 may shorten sleep latency, improve subjective sleep quality, and modulate autonomic markers such as heart rate variability (HRV).

This study is designed as a multicenter, single-arm, prospective clinical trial to observe the long-term safety and effectiveness of the digital medical device BELL-001 in patients diagnosed with insomnia. The study is conducted at three tertiary hospitals in Korea under Good Clinical Practice (GCP) and institutional review board (IRB) oversight. A total of 40 participants will be enrolled, with competitive enrollment across all sites. Participants who meet eligibility criteria based on clinical diagnosis, screening interviews, and baseline assessments will receive BELL-001.

The treatment duration is 12 weeks. Participants will be instructed to use the assigned device during their pre-sleep routine each night. Throughout the study, standardized questionnaires and validated patient-reported outcomes will be administered to assess insomnia severity, depression, anxiety, and work productivity. The outcome measures include changes in the Insomnia Severity Index (ISI), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), and Work Productivity and Activity Impairment Questionnaire (WPAI) at 4, 8, and 12 weeks compared to baseline; changes in Total Sleep Time (TST), Sleep Onset Latency (SOL), Wake After Sleep Onset (WASO), and sleep stage ratios measured via Nearable Device at 4, 8, and 12 weeks; and changes in subjective Sleep Latency (sSL), subjective Sleep Quality (sSQ), subjective Wake After Sleep Onset (sWASO), subjective number of awakenings after sleep onset, subjective Sleep Efficiency (sSE), and subjective Total Sleep Time (sTST) assessed through sleep diaries at 4, 8, and 12 weeks compared to baseline. Safety will be evaluated over the 12-week period. Additional outcome measures will include assessment of compliance and satisfaction.

Safety will be continuously evaluated throughout the study by monitoring adverse events, device-related events, and any clinically significant findings at each visit. Given the low-risk nature of the intervention - a non-invasive, non-pharmacological, software-based digital therapeutic device - serious safety concerns are not anticipated. Nonetheless, all participating sites will adhere to rigorous reporting standards, and all safety information will be reviewed by the investigators and IRBs. No independent Data Monitoring Committee (DMC) is planned due to the low-risk profile of the intervention and the presence of established safety oversight mechanisms.

All data will be collected in compliance with GCP and stored in validated electronic case report forms (eCRFs). Statistical analyses will be conducted according to a predefined statistical analysis plan, with the primary analysis based on the full analysis set.

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Jae-Eun Lee; Phone Number: +82-70-8095-4983; Email: jay.lee@belltherapeutics.com
• Study Contact Backup: Name: Hye-won Lee; Phone Number: +82-70-8095-4983; Email: hyewon.lee@belltherapeutics.com

Study Locations

• South Korea
  • Incheon, South Korea
    • Catholic Kwandong University International St. Mary's Hospital
    • Contact: Hye-Yoon Kim; Phone Number: +82+32-290-3889; Email: imkhy77@gmail.com
  • Seongnam-si, South Korea
    • CHA Bundang Hospital
    • Contact: Jungwon Shin; Phone Number: +82 31-80-3938; Email: limitsum@gmail.com
  • Seoul, South Korea
    • Seoul National University Hospital, Seoul, 03080
    • Contact: Ki-young Jung; Phone Number: 02-2072-0707; Email: jungky@snu.ac.kr

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Diagnosed with ICD-11 nonorganic insomnia (F51.0) or sleep initiation and maintenance disorder (insomnia, G47.0)
• Insomnia Severity Index (ISI) score ≥ 15
• Adults aged 19 to 75 years
• Capable of using a smartphone or tablet and has access to a stable internet connection
• Willing to provide written informed consent voluntarily and able to comply with all study procedures
• Agrees not to initiate any other insomnia treatment other than cognitive behavioral therapy for insomnia during the trial
• Has completed sleep diary entries for at least 3 out of 7 days from the day after the screening visit through the day of the baseline visit (Visit 2)
• At the baseline visit (Visit 2), sleep diary data from the preceding 7 days confirms at least 3 nights with a sleep onset latency of 30 minutes or more, or wake after sleep onset of 60 minutes or more

Exclusion Criteria:

• Individuals with severe psychiatric disorders, including major depressive disorder
• Individuals diagnosed with or suspected of having insomnia comorbid with narcolepsy (G47.4), obstructive sleep apnea (G47.30), restless legs syndrome (G25.81), periodic limb movement disorder (G47.61), or REM sleep behavior disorder (G47.52) per ICD-10-CM codes
• Individuals with active physical illness or unstable medical conditions that interfere with activities of daily living, including congestive heart failure, chronic obstructive pulmonary disease (COPD), acute pain, cerebrovascular disease (e.g., stroke), or neurodegenerative disorders (e.g., dementia, multiple sclerosis)
• Individuals whose insomnia symptoms are considered to be caused or exacerbated by the physiological effects of medications (prescription drugs or substances of abuse) or alcohol
• Individuals deemed by the investigator to be unable to participate in the study due to respiratory conditions such as asthma
• Individuals with moderate or greater hearing loss in both ears
• Individuals suspected of sleep medication dependence at the investigator's discretion
• Individuals with a history of change in the type or dosage of sleep medications, antidepressants, anticonvulsants, anxiolytics, or antipsychotics within 4 weeks prior to the baseline visit (Visit 2)
• Individuals currently reporting persistent tinnitus symptoms
• Individuals diagnosed with shift work sleep-wake disorder, or those who experience periodic insomnia or sleep-wake rhythm disturbance due to a work environment requiring repeated circadian readjustment, such as day/night shift rotation or frequent international travel
• Individuals who took PRN (as-needed) sleep medications during the screening period (including the day before Visit 1)
• Individuals who used other investigational drugs or investigational digital medical devices within 3 months prior to Visit 1 I-ndividuals with prior experience using BELL-001
• Individuals deemed inappropriate for participation in the clinical trial by the investigator for any other reason

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: BELL-001 Digital Therapeutic; Participants assigned to the experimental arm will use BELL-001, a smartphone-based digital therapeutic designed to provide personalized auditory stimulation synchronized with the user's breathing pattern. The intervention is administered nightly during the pre-sleep period for 12 weeks. The device delivers an active algorithm intended to reduce pre-sleep hyperarousal and support sleep initiation

Device: BELL-001 Digital Therapeutic; Participants assigned to the experimental arm will use BELL-001, a smartphone-based digital therapeutic designed to provide personalized auditory stimulation synchronized with the user's breathing pattern. Participants will use the device nightly during the pre-sleep period for 12 weeks. The active algorithm delivers respiratory-synchronized auditory feedback intended to reduce pre-sleep hyperarousal and support sleep initiation.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Safety data from 12 weeks of BELL-001 use	All adverse events and device deficiencies occurring during this clinical trial	From enrollment to end of treatment at 12 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Insomnia Severity Index (ISI) Score	The Insomnia Severity Index (ISI) is a validated 7-item patient-reported questionnaire that assesses nighttime symptoms, sleep satisfaction, and the impact of insomnia on daytime functioning. Higher scores indicate greater insomnia severity. This outcome measure evaluates the change in ISI total score from baseline to Weeks 4, 8, and 12.	From baseline to Weeks 4, 8, and 12
Change in Depressive Symptoms (PHQ-9)	Change in PHQ-9 score to evaluate depressive symptom severity.	Baseline to 4,8 and 12 weeks
Change in Anxiety Symptoms (GAD-7)	Change in GAD-7 score reflecting the severity of generalized anxiety	Baseline to Week 4,8 and 12
Change in Work Productivity and Activity Impairment (WPAI-GH)	Change in absenteeism, presenteeism, and activity impairment related to general health.	Baseline to Week 4, 8 and 12
Changes in Nearable Device Sleep Parameter	• Total Sleep Time (TST)	Baseline to Weeks 4, 8, and 12
Changes in the following sleep parameters collected via sleep diary and the investigational digital medical device	• Subjective Sleep Latency (sSL)	baseline to Weeks 4, 8, and 12
Changes in Nearable Device Sleep Parameter	• Sleep Onset Latency (SOL)	Baseline to Weeks 4,8, and 12
Changes in Nearable Device Sleep Parameter	• Wake After Sleep Onset (WASO)	Baseline to Weeks 4,8,and 12
Changes in Nearable Device Sleep Parameter	• Sleep Stage Ratios (Light Sleep, Deep Sleep, and REM Sleep)	Baseline to Weeks 4,8 and 12
Changes in Nearable Device Sleep Parameter	Sleep Efficiency	Baseline to Weeks 4,8 and 12
Changes in the following sleep parameters collected via sleep diary and the investigational digital medical device	Subjective Sleep Quality(sSQ)	Baseline to Weeks 4,8 and 12
Changes in the following sleep parameters collected via sleep diary and the investigational digital medical device	Subjective Wake After Sleep Onset(sWASO)	Baseline to Week 4,8, and 12
Changes in the following sleep parameters collected via sleep diary and the investigational digital medical device	Subjective Number of Awakenings after sleep onset	Baseline to Week 4,8, and 12
Changes in the following sleep parameters collected via sleep diary and the investigational digital medical device	Subjective Sleep Efficiency(sSE)	Baseline to Weeks 4,8 and 12
Changes in the following sleep parameters collected via sleep diary and the investigational digital medical device	Subjective Total Sleep Time(sTST)	Baseline to Weeks 4,8, and 12

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
User Response Assessment (compliance and satisfaction with usability)	User Response Assessment (compliance and satisfaction with usability)	From enrollment to end of treatment at 12 weeks
Respiratory acoustic data collected via smartphone microphone	Respiratory acoustic data collected via smartphone microphone	From enrollment to end of treatment at 12 weeks

Collaborators and Investigators

• Sponsor: BELL Therapeutics Inc.
• Investigators: Principal Investigator: Ki-Young Jung, Seoul National University Hospital; Principal Investigator: Jung-Won Shin, CHA Bundang Medical Center; Principal Investigator: Hye-Yoon Kim, Catholic Kwandong University International St. Mary's Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2026

Study Registration Dates

• First Submitted: April 23, 2026
• First Submitted That Met QC Criteria: May 6, 2026
• First Posted (Actual): May 13, 2026

Study Record Updates

• Last Update Posted (Actual): May 13, 2026
• Last Update Submitted That Met QC Criteria: May 6, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Biofeedback; Digital Therapeutics; Auditory stimulation; Autonomic Regulation; BELL-001; Insomnia Treatment; Breathing-Synchronized Therapy
• Additional Relevant MeSH Terms: Nervous System Diseases; Mental Disorders; Sleep Wake Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Sleep Initiation and Maintenance Disorders
• Other Study ID Numbers: BELL-001-S-KR-004

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: The sponsor has not yet determined whether individual participant data (IPD) will be shared. Decisions regarding data sharing will consider regulatory requirements, participant privacy protection, and the scientific value of potential data requests. Any future sharing of de-identified data would occur only after appropriate review and in accordance with applicable laws and institutional policies

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No