Transcutaneous Electrical Stimulation in Patients With Obstructive Sleep Apnoea

The TESLA-MICRON study is a UK-based, prospective, multi-centre, randomised controlled trial designed to evaluate the use of an investigational medical device, ZeusOSA, for the treatment of obstructive sleep apnoea in adults with poor adherence to continuous positive airway pressure (CPAP) therapy.

ZeusOSA uses gentle stimulation through the skin similar to that of a TENS machine. The device features a U-shaped lightweight silicone pad with a disposable adhesive hydrogel electrode pad (single-use) that delivers mild transcutaneous electrical nerve stimulation (TENS) to activate the hypoglossal nerve, thereby stimulating muscles to contract, particularly those associated with opening the airways (e.g., genioglossus muscle). Application of regular electrical pulses to these muscles help to maintain an open airway. The upper airway muscles might otherwise relax with sleep onset and cause vibrations and collapse in the throat whilst breathing, manifesting as snoring or sleep apnoea's or hypopneas. The stimulation level is customisable from level 1 (milder stimulation) to level 10 (stronger stimulation).

186 participants will be recruited with a prior diagnosis of obstructive sleep apnoea and low CPAP adherence at follow up (less than 4 hours/night) will be randomly assigned in a 1:1 ratio to either the intervention group or a usual care group. Recruitment will focus on a balanced ratio of men and women, as women are typically under-represented in studies of OSA and, due to a slim neck / collar size in comparison to men, likely to be responders to the TESLA treatment. Participants allocated to the intervention group will use the investigational medical device, ZeusOSA, which delivers transcutaneous electrical stimulation to the upper airway dilator muscles during sleep. The device is intended for nightly use at home over a three-month period. Participants in the usual care group will continue with ongoing CPAP therapy in accordance with current clinical practice.

All participants will undergo baseline assessments prior to randomisation, including a home-based sleep study conducted without treatment. Follow-up will include a scheduled telephone contact at approximately six weeks and a repeat assessment at three months, including a further home-based sleep study conducted with the assigned treatment and receive standard advice on sleep hygiene and lifestyle measures. The patients will then be referred for follow up to standard care in the outpatient setting at their respective sleep centre. The trial duration including recruitment is 3 years.

The study will assess the therapeutic effects of the investigational medical device on sleep-related outcomes and symptoms, as well as participant-reported quality of life. Additional objectives include evaluation of treatment adherence, comfort and acceptability of use, and monitoring of adverse events. Data collected during the study will also be used to support an assessment of healthcare resource use associated with the intervention.

The study is designed to reflect real-world use of the investigational medical device in a domiciliary setting and to identify patient characteristics associated with response to treatment. Results from this trial will inform the future clinical and regulatory development of the device for the management of obstructive sleep apnoea.

Inclusion criteria

• Adult participants (≥18 years) who have OSA with an AHI between 5-40 events/hour, as measured by the baseline sleep study (3 nights off CPAP).
• If the participant fails to use CPAP sufficiently, defined as use of CPAP for less than 4 hours/night on fewer than 70% of nights over a minimum period of 3 months prior to enrolment.
• Adults with a body mass index (BMI) of 18.5-32.0 kg/m2 (inclusive)
• Adults without significant anatomical obstruction in the upper airway (e.g., normal sized tonsils).
• Able and willing to provide informed written consent.
• Access to a smartphone and internet at home.

Exclusion criteria

• Hypercapnic patients (pCO2>6.0 kPa) or those with other features of obesity hypoventilation syndrome (elevated bicarbonate, HCO3- >28mmol/L).
• Adults with significantly enlarged tonsils (size 3-4)
• Adults with polyps or adenoids, hypoglossal nerve palsy,
• Adults with notable medical co-morbidities that could potentially impact participation in or the achievement of the study's objectives (e.g., significant heart failure (New York Heart Association, NYHA class III-IV), recent myocardial infarction (within 3 months) and significant cardiac arrhythmias, uncontrolled hypertension).
• Participants with an active psychiatric condition that, in the opinion of the Investigator, may affect the participant's capacity to provide informed consent, adhere to study procedures, actively participate in the study, or compromise the integrity of study data.
• Participants with active implantable medical devices, including but not limited to cardiac pacemakers, implantable cardioverter defibrillators (ICDs), cochlear implants, deep brain stimulation (DBS) systems, vagus nerve stimulation (VNS) devices, neurostimulators, or implanted infusion pumps.
• Participants with metallic implants in the head or neck region that, in the opinion of the Investigator, may interfere with the safe use of the investigational device.
• Participants who are physically incapacitated such as to manoeuvre the ZeusOSA device
• Adults with long facial hair that interferes with the correct placement of the hydrogel pad, and who are unwilling to shave.
• Participants with an allergy to plasters or similar products.