Obstructive Sleep ApneaNCT05501236
Ansa Cervicalis and Hypoglossal Nerve Stimulation in OSA
A study testing Grass S88 Muscle Stimulator in people with Obstructive Sleep Apnea, run by Vanderbilt University Medical Center at 1 site in United States.
Trial summary
Polysomnography (PSG) and drug-induced sleep endoscopy (DISE) are widely used diagnostic studies for assessing obstructive sleep apnea (OSA) severity and collapse patterns of the upper airway anatomy during sleep. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Obstructive Sleep Apnea
- What is being tested?
- Grass S88 Muscle Stimulator
- Type of treatment
- Medical device
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 1 siteUnited States
- Study dates
- 3 Nov 2022to 30 Nov 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Consenting adults with BMI≥ 25 and ≤ 40 kg/m2
- Obstructive sleep apnea with an AHI between 20 and 80 events/hr (with hypopneas defined by 4% oxyhemoglobin desaturations); ≥80% obstructive events.
Who cannot join
- Chronic use of opiate medications, illicit drug use, or alcohol dependency
- Other known concomitant sleep disorder (e.g., central sleep apnea, periodic limb movements, narcolepsy)
- Clinical history or evidence of cardiopulmonary disease (or oxygen use), liver, renal, immunodeficiency, neurodegenerative diseases, or previous adverse reactions to anesthesia.
- Prior upper airway reconstructive surgery excluding tonsillectomy (e.g., cleft palate repair, uvulopalatopharyngoplasty)
- Indwelling neurostimulation device (e.g. cardiac pacemaker, spinal, vagal, or hypoglossal nerve stimulator)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Vanderbilt University Medical Center
Nashville, Tennessee, 37232
Katie Estes-Hartley, RPSGT, 615-875-9214, katherine.e.hartley@vumc.org
Nicole L Jones, MS, 615-936-2807, nicole.l.jones@vumc.org
About this study
Official title: Ansa Cervicalis and Hypoglossal Nerve Stimulation in Obstructive Sleep Apnea
Polysomnography (PSG) and drug-induced sleep endoscopy (DISE) are widely used diagnostic studies for assessing obstructive sleep apnea (OSA) severity and collapse patterns of the upper airway anatomy during sleep. Hypoglossal nerve stimulation (HNS) therapy for obstructive sleep apnea suffers from variable response at the level of the soft palate. The Investigators propose a study examining the physiologic effect of ansa cervicalis stimulation (ACS) alone and in combination with HNS during PSG and DISE.
Read the detailed description
Obstructive Sleep Apnea (OSA) is a common disorder characterized by repetitive upper airway collapse during inspiration caused, in part, by a loss of neuromotor tone in specific upper airway muscles, with multiple associated health sequelae impacting millions of Americans. Patient adherence to the reference treatment, positive airway pressure (PAP), remains problematic. Despite the recent promising development of hypoglossal nerve stimulation (HNS) as a surgical therapy, its indications are limited and a proportion of eligible patients do not achieve sufficient response, leaving a critical unmet need for effective therapeutic alternatives to PAP.
This project challenges the long-held concept that the genioglossus muscle is primarily responsible for the maintenance of pharyngeal patency during sleep and proposes a novel therapeutic mechanism. It is built upon strong evidence that caudal pharyngeal traction from the trachea has a marked impact on pharyngeal patency primarily mediated through changes in lung volume. Contraction of the sternothyroid muscle, an infrahyoid cervical strap muscle that inserts onto the thyroid cartilage, also generates caudal pharyngeal traction. Our data suggest that ansa cervicalis stimulation (ACS) of the sternothyroid muscle unfolds and stretches the lateral pharyngeal walls and tensions the distal edge of the soft palate caudally, increasing airway patency.
The major hypothesis of the Investigators is that ACS overcomes specific anatomic and neuromuscular defects of upper airway control that restore pharyngeal patency in patients with OSA. This hypothesis is supported by published and preliminary data demonstrating that: (1) the degree of end-expiratory lung volume decrease in sleep correlates with observed increases in pharyngeal collapsibility, and (2) unilateral ACS increases maximum inspiratory airflow and velopharyngeal cross-sectional area during flow-limited breathing in sedated humans. These findings suggest that (3) tracheal traction, as mediated by end-expiratory lung volume (EELV), is a major contributor to airway patency in sleep. In this project, the Investigators will elucidate specific mechanisms for control of pharyngeal patency with caudal traction during drug-induced sleep endoscopy (DISE) and natural sleep (PSG). The Investigators will address these aims by characterizing (1) the effects of ACS of the sternothyroid muscle(s) on upper airway pressure-area and pressure-flow relationships, and (2) determine how subject anatomic, physiologic, and polysomnographic characteristics modulate these responses.
- Conditions
- Obstructive Sleep Apnea
- Being tested
- Grass S88 Muscle Stimulator
- Medical subject headings
- Sleep Apnea, Obstructive
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Grass S88 Muscle StimulatorDevice
The Grass S88 nerve and muscle stimulator is a widely-used tool in electromyography and nerve conduction studies. During the DISE and second sleep study, fine-wire electrodes will be placed into the hypoglossal nerve or genioglossus muscle. Two more electrodes are placed transcutaneously, proximate to the bilateral branches of the cervicalis innervating the sternothyroid muscle in the anterior neck.
| Study group | Role | What they receive |
|---|---|---|
| Muscle stimulation | Experimental | Consented participants who meet eligibility will have a drug induced sleep endoscopy (DISE) and second sleep study and the Grass S88 (or comparable) muscle stimulator. Receives: Device: Grass S88 Muscle Stimulator |
What is being measured
The primary outcome is the main question the study is designed to answer.
Basic physiologic measurements during Drug Induced Sleep Endoscopy (DISE) - Airway cross sectional diameter
Airway cross-sectional diameter (mm^2) will be measured throughout the operative procedure via flexible fiberoptic nasopharyngoscopy.
Measured: During DISE, approximately 15 minutes
Basic physiologic measurements during Drug Induced Sleep Endoscopy (DISE) - Airflow data
Airflow data (L/min) will be measured throughout the operative procedure via a pneumotachometer applied to the nose.
Measured: During DISE, approximately 15 minutes
Basic physiologic measurements during Drug Induced Sleep Endoscopy (DISE) - Upper airway pressure changes
Upper airway pressure changes (cmH20) will be measured throughout the operative procedure via a pneumotachometer applied to the nose.
Measured: During DISE, approximately 15 minutes
Basic physiologic measurements during Drug Induced Sleep Endoscopy (DISE) - Respiratory effort data
Respiratory effort data (mV) will be measured throughout the operative procedure via two respiratory inductance plethysmography belts.
Measured: During DISE, approximately 15 minutes
Basic physiologic measurements during Polysomnography (PSG) - Airflow data
Airflow data (L/min) will be measured during the sleep study via a pneumotachometer applied to the nose.
Measured: During sleep study exam (PSG), approximately 8 hours
Basic physiologic measurements during Polysomnography (PSG) - Electroencephalogram (EEG)
EEG (mV) will be collected during the sleep study via skin surface electrodes.
Measured: During sleep study exam (PSG), approximately 8 hours
Basic physiologic measurements during Polysomnography (PSG) - Electrocardiogram (EKG)
EKG (mV) will be collected during the sleep study via skin surface electrodes.
Measured: During sleep study exam (PSG), approximately 8 hours
Basic physiologic measurements during Polysomnography (PSG) - Electroocoulogram (EOG)
EOG (mV) will be collected during the sleep study via skin surface electrodes.
Measured: During sleep study exam (PSG), approximately 8 hours
Basic physiologic measurements during Polysomnography (PSG) - Electromyography (EMG)
EMG data (mV) will be collected during the sleep study via skin surface electrodes.
Measured: During sleep study exam (PSG), approximately 8 hours
Basic physiologic measurements during Polysomnography (PSG) - Respiratory effort data
Respiratory effort data (mV) will be collected during the sleep study via respiratory inductance plethysmography.
Measured: During sleep study exam (PSG), approximately 8 hours
Basic physiologic measurements during Polysomnography (PSG) - Video data
Video data will be collected during the sleep study via in-room camera.
Measured: During sleep study exam (PSG), approximately 8 hours
Secondary outcomes (1)
Amount of current needed for adequate stimulation
Obtain preliminary data regarding including the amount of current needed to adequately stimulate the ansa cervicalis stimulation (ACS) alone and in combination with hypoglossal nerve stimulation (HNS) during PSG and DISE via a neurostimulator connected to percutaneous electrodes.
Measured: Collected during operative and sleep study procedures, taking about 15 minutes.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Aug 2022
- Study start3 Nov 2022
- Primary completion30 May 2027 (estimated)
- Study completion30 Nov 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Obstructive Sleep ApneaStudies of the same condition, open and under way.
- More trials run by Vanderbilt University Medical CenterThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Model description
- All patients who meet eligibility will undergo the screening sleep study, muscle stimulation during operative DISE procedure, and muscle stimulation during second sleep study.
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Vanderbilt University Medical Center
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, David Kent, Vanderbilt University Medical Center
- Investigators
- David T. Kent, MD, Principal investigator, Vanderbilt University Medical Center
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05501236
- Sponsor's protocol ID
- 212305
- Status last verified
- Jun 2026
- First submitted
- 28 Jul 2022
- Last updated
- 29 Jun 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: We do not plan to share IPD with other researchers.
Study at a glance
From the registry record, last updated by the sponsor on 29 Jun 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Ansa Cervicalis and Hypoglossal Nerve Stimulation in Obstructive Sleep Apnea
- ClinicalTrials.gov ID
- NCT05501236
- Acronym / sponsor ID
- 212305
- Conditions
- Obstructive Sleep Apnea
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Vanderbilt University Medical CenterUniversity, hospital or other
- Study start
- 3 Nov 2022 (actual)
- Primary completion
- 30 May 2027 (estimated)
- Study completion
- 30 Nov 2027 (estimated)
- First posted
- 15 Aug 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Polysomnography (PSG) and drug-induced sleep endoscopy (DISE) are widely used diagnostic studies for assessing obstructive sleep apnea (OSA) severity and collapse patterns of the upper airway anatomy during sleep. Hypoglossal nerve stimulation (HNS) therapy for obstructive sleep apnea suffers from variable response at the level of the soft palate. The Investigators propose a study examining the physiologic effect of ansa cervicalis stimulation (ACS) alone and in combination with HNS during PSG and DISE.
Detailed description
Obstructive Sleep Apnea (OSA) is a common disorder characterized by repetitive upper airway collapse during inspiration caused, in part, by a loss of neuromotor tone in specific upper airway muscles, with multiple associated health sequelae impacting millions of Americans. Patient adherence to the reference treatment, positive airway pressure (PAP), remains problematic. Despite the recent promising development of hypoglossal nerve stimulation (HNS) as a surgical therapy, its indications are limited and a proportion of eligible patients do not achieve sufficient response, leaving a critical unmet need for effective therapeutic alternatives to PAP.
This project challenges the long-held concept that the genioglossus muscle is primarily responsible for the maintenance of pharyngeal patency during sleep and proposes a novel therapeutic mechanism. It is built upon strong evidence that caudal pharyngeal traction from the trachea has a marked impact on pharyngeal patency primarily mediated through changes in lung volume. Contraction of the sternothyroid muscle, an infrahyoid cervical strap muscle that inserts onto the thyroid cartilage, also generates caudal pharyngeal traction. Our data suggest that ansa cervicalis stimulation (ACS) of the sternothyroid muscle unfolds and stretches the lateral pharyngeal walls and tensions the distal edge of the soft palate caudally, increasing airway patency.
The major hypothesis of the Investigators is that ACS overcomes specific anatomic and neuromuscular defects of upper airway control that restore pharyngeal patency in patients with OSA. This hypothesis is supported by published and preliminary data demonstrating that: (1) the degree of end-expiratory lung volume decrease in sleep correlates with observed increases in pharyngeal collapsibility, and (2) unilateral ACS increases maximum inspiratory airflow and velopharyngeal cross-sectional area during flow-limited breathing in sedated humans. These findings suggest that (3) tracheal traction, as mediated by end-expiratory lung volume (EELV), is a major contributor to airway patency in sleep. In this project, the Investigators will elucidate specific mechanisms for control of pharyngeal patency with caudal traction during drug-induced sleep endoscopy (DISE) and natural sleep (PSG). The Investigators will address these aims by characterizing (1) the effects of ACS of the sternothyroid muscle(s) on upper airway pressure-area and pressure-flow relationships, and (2) determine how subject anatomic, physiologic, and polysomnographic characteristics modulate these responses.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
- Model description
- All patients who meet eligibility will undergo the screening sleep study, muscle stimulation during operative DISE procedure, and muscle stimulation during second sleep study.
| Arm | Type | Receives |
|---|---|---|
| Muscle stimulation | Experimental | Device: Grass S88 Muscle StimulatorConsented participants who meet eligibility will have a drug induced sleep endoscopy (DISE) and second sleep study and the Grass S88 (or comparable) muscle stimulator. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Consenting adults with BMI≥ 25 and ≤ 40 kg/m2
- Obstructive sleep apnea with an AHI between 20 and 80 events/hr (with hypopneas defined by 4% oxyhemoglobin desaturations); ≥80% obstructive events.
Key exclusion criteria (5 listed)
- Chronic use of opiate medications, illicit drug use, or alcohol dependency
- Other known concomitant sleep disorder (e.g., central sleep apnea, periodic limb movements, narcolepsy)
- Clinical history or evidence of cardiopulmonary disease (or oxygen use), liver, renal, immunodeficiency, neurodegenerative diseases, or previous adverse reactions to anesthesia.
- Prior upper airway reconstructive surgery excluding tonsillectomy (e.g., cleft palate repair, uvulopalatopharyngoplasty)
- Indwelling neurostimulation device (e.g. cardiac pacemaker, spinal, vagal, or hypoglossal nerve stimulator)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Grass S88 Muscle StimulatorThe Grass S88 nerve and muscle stimulator is a widely-used tool in electromyography and nerve conduction studies. During the DISE and second sleep study, fine-wire electrodes will be placed into the hypoglossal nerve or genioglossus muscle. Two more electrodes are placed transcutaneously, proximate to the bilateral branches of the cervicalis innervating the sternothyroid muscle in the anterior neck. | Device | Muscle stimulation |
Primary outcome
Basic physiologic measurements during Drug Induced Sleep Endoscopy (DISE) - Airway cross sectional diameter
Time frame: During DISE, approximately 15 minutes
Airway cross-sectional diameter (mm^2) will be measured throughout the operative procedure via flexible fiberoptic nasopharyngoscopy.
Basic physiologic measurements during Drug Induced Sleep Endoscopy (DISE) - Airflow data
Time frame: During DISE, approximately 15 minutes
Airflow data (L/min) will be measured throughout the operative procedure via a pneumotachometer applied to the nose.
Basic physiologic measurements during Drug Induced Sleep Endoscopy (DISE) - Upper airway pressure changes
Time frame: During DISE, approximately 15 minutes
Upper airway pressure changes (cmH20) will be measured throughout the operative procedure via a pneumotachometer applied to the nose.
Basic physiologic measurements during Drug Induced Sleep Endoscopy (DISE) - Respiratory effort data
Time frame: During DISE, approximately 15 minutes
Respiratory effort data (mV) will be measured throughout the operative procedure via two respiratory inductance plethysmography belts.
Basic physiologic measurements during Polysomnography (PSG) - Airflow data
Time frame: During sleep study exam (PSG), approximately 8 hours
Airflow data (L/min) will be measured during the sleep study via a pneumotachometer applied to the nose.
Basic physiologic measurements during Polysomnography (PSG) - Electroencephalogram (EEG)
Time frame: During sleep study exam (PSG), approximately 8 hours
EEG (mV) will be collected during the sleep study via skin surface electrodes.
Basic physiologic measurements during Polysomnography (PSG) - Electrocardiogram (EKG)
Time frame: During sleep study exam (PSG), approximately 8 hours
EKG (mV) will be collected during the sleep study via skin surface electrodes.
Basic physiologic measurements during Polysomnography (PSG) - Electroocoulogram (EOG)
Time frame: During sleep study exam (PSG), approximately 8 hours
EOG (mV) will be collected during the sleep study via skin surface electrodes.
Basic physiologic measurements during Polysomnography (PSG) - Electromyography (EMG)
Time frame: During sleep study exam (PSG), approximately 8 hours
EMG data (mV) will be collected during the sleep study via skin surface electrodes.
Basic physiologic measurements during Polysomnography (PSG) - Respiratory effort data
Time frame: During sleep study exam (PSG), approximately 8 hours
Respiratory effort data (mV) will be collected during the sleep study via respiratory inductance plethysmography.
Basic physiologic measurements during Polysomnography (PSG) - Video data
Time frame: During sleep study exam (PSG), approximately 8 hours
Video data will be collected during the sleep study via in-room camera.
1 secondary outcome
Amount of current needed for adequate stimulation
Time frame: Collected during operative and sleep study procedures, taking about 15 minutes.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 29 Jun 2026.
- Individual participant dataSharing planned: No. We do not plan to share IPD with other researchers.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
David T. Kent, MD principal investigator
Vanderbilt University Medical Center
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Grass S88 Muscle Stimulator in people with Obstructive Sleep Apnea, run by Vanderbilt University Medical Center at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 29 Jun 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Katie Hartley-Estes, RPSGT (615-875-9214, katherine.e.hartley@vumc.org), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Basic physiologic measurements during Drug Induced Sleep Endoscopy (DISE) - Airway cross sectional diameter (time frame: During DISE, approximately 15 minutes). The study lists 11 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 29 Jun 2026.