In some embodiments, a method may include monitoring use of a medical device. The method may include positioning a wearable harness of a medical device on a subject. The method may include selectively positioning at least some of a plurality of engines on and/or adjacent at least one treatment area. The method may include applying an oscillation force to at least one of the treatment areas using at least some of the engines. The method may include mobilizing at least some secretions in an airway within the subject substantially adjacent the treatment areas. The method may include monitoring use of the medical device by the subject using a controller associated with the medical device to determine if the medical device has been used effectively as prescribed.