Airway Muscle Training for Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a common disorder characterized by intermittent narrowing or closure of the upper airway during sleep. Loss of muscle tone with sleep onset and decreases in ventilatory drive following the loss of the wakefulness stimuli to breathe combine to result in upper airway closure in patients with structurally susceptible upper airways. We hypothesize that training of upper airway muscles will improve sleep apnea by augmenting the resting upper airway muscle tone and ability of the muscles to respond to negative intraluminal pressure. Training with a primitive wind instrument (such as a Digeridoo) and oral pharyngeal exercises (OPE) used in speech therapy have been shown to improve sleep apnea. Individuals who play certain types of wind instruments appear to have a lower risk of sleep apnea. However, to date the mechanism of improvement and the optimal method of upper airway training have not been well defined. We recently completed a study with a facial exerciser (Facial Flex) designed to improve facial muscle tone and found a decrease in snoring in a group with loud snoring but minimal sleep apnea. A group of UF physiologists (including co investigators Drs. Davenport and Silverman) have also demonstrated that brief periods of training with high inspiratory and/or expiratory threshold loads improved cough and swallowing in patients with impairment in upper airway function. Although respiratory pump muscles provide the driving force for pressure generation during training with pressure threshold loads, the upper airway muscle must maintain a patent upper airway resisting high negative or positive intraluminal pressures. For example, the palate must maintain a seal preventing air escape through the nose when high positive pressure is generated through a mouthpiece. Of interest a limited number of very high intensity efforts appears to be the optimal way to train muscles.

We propose targeting a group of mild to moderate OSA patients (apnea-hypopnea index < 30/hour) who are not severely obese (BMI < 35 Kg/M2) and do not have significant structural abnormalities of the upper airway or muscle dysfunction. We will perform a randomized controlled trial (training versus sham training) with 25 subjects in each treatment arm using two months of daily training (5 out of 7 days each week). A home sleep study (including EEG) will be performed before and following the training. The change in the apnea-hypopnea index adjusted for sleep stage and body position will be compared. Use of home sleep studies will dramatically reduce the cost of the study. A sleep technologist will educate subjects on performance of maneuvers and meet with them weekly to observe the subject's technique. A training log will be kept by the subjects using training schedule sheets and daily training will be monitored through weekly web-based communication with a study clinician.