The overall objectives of the proposed research are to: 1. Evaluate the diagnostic validity of a novel mechano-acoustic signatures of task-characteristic activity during symptomatic and asymptomatic breathing in Exercise-Induced Laryngeal Obstruction (EILO) patients with the use of a novel miniature, soft wearable skin-mounted device, 2. Identify the mechanism/s of paradoxical respiratory control in EILO by quantifying the relationship between pulmonary mechanics, partial pressure of carbon dioxide (PCO2) maintenance, and vocal fold aperture prior to and during symptomatic and asymptomatic exercise ventilation, and 3. Identify unique biophysiological factors contributing to EILO among exercisers with and without EILO. Findings will be highly novel and clinically significant for early identification and management of EILO. The main study will enroll 60 participants with EILO and 60 without EILO to complete three separate visits: 1. Exercise treadmill study 2. Free running with the device on the neck 3. Undergoing MRI (Magnetic Resonance Imaging) of the vocal tract. An additional substudy limited to the mechanoacoustic device will enroll 10 additional participants (5 healthy and 5 with EILO). These participants will complete a single study visit during which the mechano-acoustic device will be worn during four sequential conditions.
Main Study At the first study visit, participants will sign informed consent, complete study questionnaires, have their height, weight, and body composition measured, and perform resting pulmonary function tests. Participants will then warm up on the treadmill for 10 minutes. An endoscope will be placed in one nostril until the vocal folds are visible, and subjects will be fitted with a chest strap heart rate monitor, an oro-nasal face mask, and the mechanoacoustic device. This sensor is placed on the neck with a velcro band. Participants will then undergo a graded exercise test during which a carbon-dioxide enriched gas mixture will be administered. The amount of the gas mixture will be titrated based on measures of the participant's breathing and lung function. This visit will be video recorded. At the second study visit, participants will be asked to again wear the mechanoacoustic device while free running for 10 minutes in a large room or on a track. This visit will be video-recorded. At the third study visit, participants will be asked to undergo an MRI scan, during which they will perform a variety of breathing exercises including rest breathing, rapid breathing, pursed lip breathing, sniff, and open mouth breathing. Research personnel will instruct participants in the various breathing techniques prior to the scan. Device Only Substudy Participants will be evaluated using the mechanoacoustic device only at a single visit. Participants will wear the neck device during four sequential conditions: seated rest indoors (15 minutes); standing outdoors (15 minutes); walking outdoors (15 minutes); running outdoors (15 minutes). This visit will be video-recorded.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
OTHER
Masking
NONE
Enrollment
130
Breathing Hypercapnic Gas (10% CO2 (carbon dioxide) and 21%O2 (oxygen), balance N210% (nitrogen))
A custom developed mechanoacoustic sensor will be worn on the neck using a Velcro strap. The device will collect audio recordings of breathing and breath sounds and will collect muscle activity from the neck muscles.
Indiana University
Bloomington, Indiana, United States
RECRUITINGDevice measurements from real time running
Muscle activation of cricothyroid/sternohyoid muscle measured via customized surface electromyography amplifier
Time frame: Baseline and Periprocedural
Device measurements from real time running
Normalized amplitude (100% of maximum voluntary contraction) Burst duration (milliseconds) prior to and during Exercise-Induced Laryngeal Obstruction event of laryngeal closure.
Time frame: Baseline and Periprocedural
Device measurements from real time running
Exercise-Induced Laryngeal Obstruction signature detected via ultra-low noise micro-electromechanical (MEMS) microphone amplitude (dB) prior to and during EILO. EILO signature detected via accelerometer (g, where g represents the gravitational acceleration of 9.8 m/s2) prior to and during EILO
Time frame: Baseline and Perioprocedural
Treadmill testing
Breathing frequency (breaths per minute)
Time frame: Baseline and Perioprocedural
Treadmill testing
Tidal volume (Liters)
Time frame: Base-line
Treadmill testing
Ventilation (Liters/minute)
Time frame: Breath-by-breath baseline and Perioprocedural
Treadmill testing
Partial pressure of arterial carbon dioxide estimated from end-tidal partial pressure of carbon dioxide; PetCO2) (mmHg)
Time frame: Baseline and Periprocedural
MRI Upper Airway Size
Length (mm), width (mm), and cross-sectional area (mm2) of oropharynx, supraglottis, glottis, immediate subglottis.
Time frame: Baseline
Upper Airway Aerodynamics
pressure (Pa) across oropharynx, supraglottis, and subglottis
Time frame: Baseline and Periprocedural
Upper Airway Aerodynamics
volume flow rate (l/s) across oropharynx, supraglottis, and subglottis
Time frame: Baseline and Periprocedural
Upper Airway Aerodynamics
flow velocities (m/s) across oropharynx, supraglottis, and subglottis
Time frame: Baseline and Periprocedural
Self-rating of dyspnea
Dyspnea self-rating of breathing intensity and breathing unpleasantness rating on Visual Analog Scale of 0 to 100mm
Time frame: Baseline
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