Purpose The use of noninvasive ventilation (NIV) is on the rise as an alternative to tracheostomy for individuals with neuromuscular disorders with life-prolonging and quality-of-life benefits. This pilot study was designed to determine if mouthpiece NIV (M-NIV) alters speech in individuals with muscular dystrophy (MD). Method Eight men (23-44 years), seven with Duchenne MD and one with Becker MD, who used daytime M-NIV, were asked to sustain phonation, count, and read under three conditions: (a) (no instructions), (b) (cued to use M-NIV with all speaking breaths), and (c) (as tolerated). Breath group and inspiratory durations, syllables/breath group, and relative sound pressure level were determined from audio and video recordings. Results Uncued condition: Participants used the ventilator for all inspirations that preceded sustained phonation and counting. During reading, four participants used M-NIV for all inspirations, one never used it, and three used it for some (19%-41%) inspirations. With- versus Without-M-NIV conditions: Breath group duration was significantly longer across all tasks, syllables per breath group were significantly greater during reading, and inspiratory pause duration during reading was significantly longer with M-NIV than without. Sound pressure level was significantly higher during the first second of sustained phonation with M-NIV (though not for counting and reading). Two participants were unable to complete the reading task audibly without using their M-NIV. Conclusions Speech may be better with M-NIV than without because it is possible to produce longer breath groups and some people with severe respiratory muscle weakness may not be able to speak at all without ventilator-supplied air. Nevertheless, the longer inspiratory pauses that accompany M-NIV may interrupt the flow of speech. Future research is needed to determine the most effective way to use M-NIV for speaking and whether training participants in its use can bring even greater speech benefits
