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Trial registered on ANZCTR


Registration number
Help: Registration number
ACTRN12626001235392
Ethics application status
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Approved
Date submitted
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10/09/2026
Date registered
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12/10/2026
Date last updated
Help: Date last updated
12/10/2026
Date data sharing statement initially provided
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12/10/2026
Type of registration
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Prospectively registered

Titles & IDs
Public title
The Effect of Palatal Stimulation Via Customised Oral Appliance on Obstructive Sleep Apnoea
Scientific title
The Effect of Transmucosal Palatal Stimulation via Custom Oral Appliance on Apnoea-Hypopnoea Index in Obstructive Sleep Apnoea: A Single-Night Randomised Crossover Study with Within-Subject Controls
Additional trial identifiers [1] 318399 0
SOM-001
Universal Trial Number (UTN)
Trial acronym
Related trial records

Health condition
Health condition(s) studied:
Obstructive Sleep Apnoea 343544 0
Condition category
Condition code
Respiratory 339653 339653 0 0
Sleep apnoea

Intervention/exposure
Study type
Interventional
Description of the intervention or exposure
Non-invasive transmucosal palatal stimulation via custom oral appliance delivered over a single night in a polysomnography lab setting.

Participants receive non-invasive transmucosal palatal stimulation, delivered through a custom-fabricated upper-arch oral appliance, during a single attended overnight in-laboratory polysomnogram (PSG).
Oral appliance. A patient-specific upper-arch appliance (similar in form to an orthodontic retainer or occlusal splint) covering the upper dental arch and hard palate, manufactured by the sponsor using digital intraoral scans (Trios 5, 3Shape, Copenhagen, Denmark) and 3D-printed dental material.
Stimulator. An external programmable constant-current pulse generator (DS8R, Digitimer Ltd, UK) delivers electrical stimulation as operator-initiated bursts timed to inspiration from the real-time PSG airflow signal, or on a pre-programmed respiratory duty cycle set from the participant's own respiratory rate and inspiratory time measured during stable NREM sleep. All stimulation events are logged automatically to onboard memory.

Visit 1 — screening and appliance manufacture (Day –30 to Day 0, Illawarra ENT Head and Neck Clinic). Eligibility review, informed consent, medical and sleep history, oral and airway examination, and digital intraoral scan. The appliance is then fabricated.

Visit 2 — intervention night (Night 1, Illawarra Sleep Medicine Centre).

Phase 1: the appliance is fitted and seated, stimulation is trialed while awake to establish sensory thresholds.

Phase 2: a standard Level 1 PSG montage is applied. After sleep onset and confirmation of stable NREM sleep, amplitude is titrated to a therapeutic amplitude from 0mA to a maximum of 25mA. Alternating stimulation (STIM) and non-stimulation (NO-STIM) blocks of approximately 10 minutes each are acquired in stable NREM sleep and approximately 5 minutes each in stable REM sleep, separated by 2–5 minute transition periods, and repeated for the remainder of the night as tolerated. Total PSG recording is approximately 6–8 hours. Usual OSA therapy (CPAP, oral appliance or other) is withheld for the study night.

Titration Procedure: Once the sleep technologist has confirmed at least 5 minutes of stable NREM sleep, amplitude is increased in 0.1mA-1mA steps, manually timed to inspiration. The minimum therapeutic threshold is the lowest amplitude that improves the inspiratory flow waveform or resolves obstructive events for at least 3 consecutive breaths without cortical arousals (within 3 seconds of stimulation). The amplitude used for the rest of the night is set 1–2 mA below the arousal threshold, or at the minimum therapeutic threshold if no arousal occurs. The same process is repeated in REM sleep to set a separate REM amplitude.

Morning after the study night. Oral mucosal examination and photodocumentation, tolerability questionnaire, and adverse event assessment. Participants are then discharged.

Follow-up (Day 1–3). A telephone call within 48 hours to assess delayed adverse events and resolution of any morning symptoms. Study participation then concludes.

Who administers the intervention. Sponsor technical staff and an ASA-certified sleep technologist jointly operate the stimulation system. Both are present for all stimulation procedures. The technologist monitors the participant continuously via PSG signals and video throughout the night and can communicate by intercom.
Adherence and fidelity monitoring. The intervention is delivered on a single supervised night, so adherence is not a measured outcome. Study personnel follow written checklists for titration and block acquisition. Automatic system logging of stimulation and start/stop times provides objective verification of delivered stimulation, and is reconciled against the submental EMG stimulation artefact on the PSG.

Stimulation is reduced or ceased according to pre-specified criteria, including repeated stimulation-associated arousals, participant discomfort or request, appliance dislodgement, device malfunction, or any safety concern raised by study personnel.
Intervention code [1] 335295 0
Treatment: Devices
Description of the comparator or control
Within-subject, within-night matched non-stimulation periods, each participant serving as their own control.

Matched within-participant non-stimulation (NO-STIM) control periods. During NO-STIM blocks the oral appliance remains in situ and connected, with stimulation amplitude set to 0 mA. Block duration is matched to the corresponding STIM block (approximately 10 minutes in NREM, approximately 5 minutes in REM), within the same sleep stage, on the same night, with the same PSG montage and the same AASM scoring criteria applied identically to both conditions. The order of STIM and NO-STIM blocks is randomised, and allocation is revealed immediately before stimulation begins.
Control group
Active

Outcomes
Primary outcome [1] 346824 0
Change in the apnoea–hypopnoea index (AHI, events/hour) between stimulation (STIM) and matched non-stimulation (NO-STIM) periods, assessed within participants.
Timepoint [1] 346824 0
Assessed during the single overnight in-laboratory polysomnogram (Night 1, approx 8 hours). AHI is calculated over matched STIM and NO-STIM periods totalling at least 20 minutes per condition in NREM sleep and at least 10 minutes per condition in REM sleep, aggregated from shorter segments where continuous acquisition is not achieved.
Secondary outcome [1] 467704 0
NREM AHI Change
Timepoint [1] 467704 0
During the single overnight polysomnogram (Night 1, ~8 hours), over the matched stage-specific blocks totalling at least 20 minutes per condition in NREM sleep.
Secondary outcome [2] 467705 0
Snoring Intensity
Timepoint [2] 467705 0
During the single overnight polysomnogram (Night 1, ~8 hours), over the matched STIM and NO-STIM blocks.
Secondary outcome [3] 467708 0
Oxygen desaturation index: number of at least 3% and at least 4% oxygen desaturation events per hour of sleep, derived from continuous pulse oximetry, compared between STIM and NO-STIM periods.
Timepoint [3] 467708 0
During the single overnight polysomnogram (Night 1, ~8 hours), over the matched STIM and NO-STIM blocks.
Secondary outcome [4] 467709 0
Stimulation related cortical arousal and awakening
Timepoint [4] 467709 0
During the single overnight polysomnogram (Night 1, ~8 hours), over the matched STIM and NO-STIM blocks.
Secondary outcome [5] 467710 0
Incidence, severity and relatedness of adverse events.
Timepoint [5] 467710 0
Assessed continuously during the overnight polysomnogram (Night 1), at the post-PSG oral examination on the morning after the study night (Day 1), and at the 48-hour follow-up telephone call (Day 1–3), with passive surveillance to Day 7.
Secondary outcome [6] 467714 0
Apnoea index
Timepoint [6] 467714 0
During the single overnight polysomnogram (Night 1), over the matched STIM and NO-STIM blocks.
Secondary outcome [7] 467715 0
Hypopnoea index
Timepoint [7] 467715 0
During the single overnight polysomnogram (Night 1), over the matched STIM and NO-STIM blocks.
Secondary outcome [8] 468858 0
REM AHI Change
Timepoint [8] 468858 0
During the single overnight polysomnogram (Night 1, ~8 hours), over the matched stage-specific blocks totalling at least 10 minutes per condition in REM sleep.

Eligibility
Key inclusion criteria
1. Age: >/=18 years at the time of consent.
2. OSA Diagnosis: Confirmed diagnosis of obstructive sleep apnoea.
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Healthy volunteers
No
Key exclusion criteria
Active oral/pharyngeal pathology
Appliance material allergy
Active implantable medical devices
Epilepsy or seizure history
Significant central sleep apnoea or other confounding sleep disorder
Unstable cardiovascular, respiratory or neurological disease
Sleep-altering medication not able to be safely ceased
Pregnancy or active fertility treatment
Concurrent interventional device trial participation
Investigator-directed exclusions that would affect participant safety or confound study outcomes

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Within-Subject Randomisation: Order of stimulation and non-stimulation periods. Randomisation sequence concealed from the study team in sealed envelopes.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Computer-generated randomization schedule using a random number generator
Masking / blinding
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Safety/efficacy
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
30/10/2026
Actual
Date of last participant enrolment
Anticipated
1/06/2027
Actual
Date of last data collection
Anticipated
1/07/2027
Actual
Sample size
Target
16
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
NSW

Funding & Sponsors
Funding source category [1] 322975 0
Commercial sector/Industry
Name [1] 322975 0
Somnair Pty Ltd
Country [1] 322975 0
Australia
Primary sponsor type
Commercial sector/Industry
Name
Somnair Pty Ltd
Address
Country
Australia
Secondary sponsor category [1] 325904 0
None
Name [1] 325904 0
Address [1] 325904 0
Country [1] 325904 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 321386 0
Bellberry Human Research Ethics Committee G
Ethics committee address [1] 321386 0
Ethics committee country [1] 321386 0
Australia
Date submitted for ethics approval [1] 321386 0
Approval date [1] 321386 0
04/09/2026
Ethics approval number [1] 321386 0

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 153570 0
Prof Stuart Mackay
Address 153570 0
Illawarra ENT Head and Neck Clinic, Ste 1-2 8/10 Victoria St Wollongong NSW 2500
Country 153570 0
Australia
Phone 153570 0
+61 2 4226 1055
Fax 153570 0
Email 153570 0
[email protected]
Contact person for public queries
Name 153571 0
Anders Sideris
Address 153571 0
Somnair Pty Ltd, 3 Lennox St Mosman NSW 2088
Country 153571 0
Australia
Phone 153571 0
+61 2 9969 8285
Fax 153571 0
Email 153571 0
[email protected]
Contact person for scientific queries
Name 153572 0
Stuart Mackay
Address 153572 0
Illawarra ENT Head and Neck Clinic, Ste 1-2 8/10 Victoria St Wollongong NSW 2500
Country 153572 0
Australia
Phone 153572 0
+61 2 4226 1055
Fax 153572 0
Email 153572 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
No
No IPD sharing reason/comment: Data produced from this trial is proprietary, commercial-in-confidence.



What supporting documents are/will be available?

No Supporting Document Provided


Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.