Effect of Added Varnum Mouthpiece on Pharyngeal Collapsibility and Sleep Apnea Severity in Mouth Breathers.

Obstructive sleep apnea (OSA) is a common disorder that remains under-treated due few
therapeutic options beyond continuous positive airway pressure (CPAP). In patients with OSA,
upper airway obstruction is caused by collapse of pharyngeal structures during sleep. It is
known that mouth breathing increases upper-airway collapsibility during sleep and may
contribute to the occurrence of sleep disordered breathing. In addition, it was shown that
patients with a high percentage of mouth breathing during sleep were less adherent to CPAP
therapy. Therefore, one potential solution to these problems is to use Varnum's mouthpiece to
prevent mouth breathing during sleep.

The overall objective of the current study is to improve upper airway collapsibility and
sleep apnea in OSA patients who have a high percentage of mouth breathing during sleep. The
investigators' central hypothesis is that preventing the lips from parting with the Varnum
device will reduce oral breathing and thereby OSA severity in mouth breathers. The
investigators chose this hypothesis because "taping the mouth closed" with a simple device
such as the Varnum mouthpiece is the most straightforward approach to dealing with this
common problem. With this research, it could become possible to overcome one of the major
problems contributing to sleep apnea - mouth breathing.

Therefore, the investigators aim to test the effect of the Varnum mouthpiece on pharyngeal
collapsibility and OSA severity in patients who identify themselves as mouth breathers. The
investigators' working hypothesis is that the device will keep the lips from separating and
thereby prevent oral breathing. In doing so, it may help keep the airway more patent (by
promoting nasal instead of oral breathing) in self-described mouth breathers and thus reduce
OSA severity. On the contrary, the investigators believe patients who do not identify
themselves as mouth breathers might not benefit significantly from the Varnum device.

The expected outcome of this study is validation of new device for improving sleep apnea in a
large subgroup of easily identifiable OSA patients, namely self-described mouth breathers.
Such a device could advance the field by providing more effective alternative treatments.

Inclusion Criteria:

- Presence of obstructive sleep apnea (AHI>10 events/hr)

Exclusion Criteria:

- Serious co-morbidities including lung disease, heart disease, renal disease

- Medications affecting respiration or sleep

Mouth breather subgroup inclusion criteria: self-described mouth breathing habit during
sleep.

non-mouth breathing subgroup inclusion criteria: absence of self-described mouth breathing
during sleep