Continuous positive airway pressure (CPAP) is the gold standard to normalize breathing during sleep in patients with obstructive sleep apnea syndrom (OSA). Many patients will not tolerate or will not accept CPAP. Implanted nerve stimulation is a novel therapy for OSA patients that restores the upper airway potency using unilateral XII nerve electric stimulation.

The principal objective of this study is short-term efficacy of a new treatment for OSA on blood pressure variability during sleep.

Obstructive sleep apnea (OSA) syndrome had become over the last decade a serious health concern due to its high prevalence which raise 10% of the general population.

It is characterized by recurrent episodes of airflow obstruction in the upper airway (UA) consequence of passive collapse of the UA, particularly at the tongue level. These collapses induce recurrent asphyxia that results in oxygen desaturations with persistant and crescendo respiratory efforts inducing arousals from sleep.

Indeed, despite its large efficacy some of the patients will never accept continuous positive airway pressure treatment or will not tolerate. To this extent, alternative treatement has been developed: implanted hypoglossal stimulation. This treatment has been developed by Inspire Medical Device. The Inspire® system is intended to prevent base-of-tongue obstruction as well as specific soft palate obstructions by stimulating the hypoglossal nerve synchronous with respiration.

A selection processus will be applied in order to identify the patients that will be good responders to the hypoglossal stimulation.

The main criterion of selection is based on Drug Induced Sleep Endoscopy(DISE) that will be performed by a trained endoscopist dedicated to this study.

This sleep endoscopy allows to visualize during induced sleep the shape of the UA and the type of collapsus. Indeed an antero-posterior collapsus is related to a good response to hypoglossal nerve stimulation while complete concentric obstruction at velopharyngeal is a predictor of poor response.

In this pilot study, the investigators evaluate as a primary outcome the delta range of blood pressure during sleep but also other cardiovascular indexes targeting blood pressure and heart rate variability as secondary outcomes.

Inclusion Criteria:

• Patient aged 18 to 80 years old
• Patient with moderate to severe OSA based on an established diagnosis of OSA (15≤AHI<65) by polysomnography or respiratory polygraphy not older thant three years.
• Patient with moderate to severe OSA naïve of treatment or with difficulty accepting or adhering to CPAP treatment.
• Willing and capable to have stimulation hardware permanently implanted, and to use the patient programmer to activate the stimulation
• Willing and capable to return for all follow-up visits and conduct sleep studies at home, including the evaluation procedures and filling out questionnaires
• Willing and capable of providing written informed consent.

Exclusion Criteria:

• Any anatomical finding that would compromise the performance of upper airway stimulation, such as the presence of complete concentric collapse of the soft palate
• Have any condition or procedure that has compromised neurological control of the upper airway
• Unable to operate the patient programmer
• Pregnant or plan to become pregnant, and breastfeeding women
• Require magnetic resonance imaging (MRI)
• Have an implantable device that may be susceptible to unintended interaction with the Inspire system.

Additional exclusions for study purposes only

• Body Mass Index (BMI) of >32
• Central + mixed apneas > 25% of the total apnea-hypopnea index (AHI)
• Neuromuscular disease
• Hypoglossal-nerve palsy
• Severe restrictive or obstructive pulmonary disease
• Moderate-to-severe pulmonary arterial hypertension
• Severe valvular heart disease
• New York Heart Association class III or IV heart failure
• Recent myocardial infarction or severe cardiac arrhythmias (within the past 6 months)
• Persistent uncontrolled hypertension despite medication use
• Coexisting nonrespiratory sleep disorders that would confound functional sleep assessment
• Any chronic medical illness or condition that contraindicates a surgical procedure under general anesthesia, as judged by the clinical study Investigator
• a terminal illness with life expectancy < 12 months
• Active psychiatric disease (psychotic illness, major depression, or acute anxiety attacks) which prevents subject compliance with the requirements of the investigational study testing
• Radiotherapy or ablation therapy of the head and/or neck
• Surgical resection for cancer or congenital malformations in the larynx, tongue, or throat(with exception of tonsillectomy and/or adenoidectomy)
• Previous surgery within 3 months performed on the soft-palate tissue
• Obvious fixed upper airway obstructions (tumors, polyps, unilateral nasal obstruction)
• Need for chronic supplemental oxygen therapy for any other reason, pO2 (partial pressure of oxygen) < 55 mm Hg
• Clinical evidence of severe renal failure (Stage 4 or 5) undergoing dialysis or expected to institute dialysis within 6 months
• Patients on medication that may alter consciousness, the pattern of respiration or sleep architecture (for example, benzodiazepiones, opiates, neuroleptics, prescription stimulants, phenothiazine, or any form of chemical substance abuse)
• Patients taking blood thinning medications (for example warfarin, aspirin, plavix or other blood thinning agents which cannot be safety stopped or bridged temporarily to allow surgery to take place)
• Any other reason for the investigator deems that the subject is unfit for participation in the study
• Subject in exclusion period for another study
• Subject under administrative or judicial control.

Only patient will be blind. He doesn't know if INSPIRE therapy was activated or not