Changed scientific strategy. No participants were enrolled.

This study has been developed in order to demonstrate the validity of the Sparkle respiratory effort signal.

The rationale for undertaking this study is to demonstrate that the agreement between the Sparkle respiratory effort signal amplitude and esophageal manometry is non-inferior to the agreement between the thoracic belt respiratory effort signal amplitude and esophageal manometry. Data collection will be completed within a single visit, in which participants will undergo simultaneous measurement using the Sparkle device, respiratory belts, and esophageal manometry. Data collection will be completed during wakefulness, while participants undergo a series of breathing maneuvers.

Inclusion Criteria:

• Aged ≥18 years;
• Fluent in English;
• Able to provide informed consent.

Exclusion Criteria:

• Contraindication to esophageal pressure monitoring, including a sensitive gag reflex (determined by a positive response to the screening question "do you sometimes or often gag while brushing your teeth?"), dysphagia, nasal obstruction, and/or esophageal disorder likely to impact placement of the balloon;
• History of allergic reactions to medical adhesives;
• Known allergy to lidocaine;
• Known seizure disorder;
• Severe medical condition (controlled or uncontrolled) impacting breathing including neuromuscular disease, chronic obstructive pulmonary disease, respiratory failure or insufficiency, or requirement for oxygen therapy;
• Chronic cardiopulmonary or renal disease, including a history of irregular heart rhythms;
• At risk for excessive bleeding including use of anticoagulants;
• An employee, or spouse of an employee, of a company that designs, sells, or manufactures sleep related products (including Philips);
• An employee, or spouse of an employee, of Pulmonary and Critical Care Associates of Baltimore.