The primary purpose of this investigation was to explore the effects of variable doses of home practice Vocal Function Exercises (VFEs) on attainment of pre-established maximum phonation time (MPT) goals in individuals between the ages of 18 and 25 with normal voice. A secondary purpose was to monitor for potentially toxic effects of high doses of VFEs. Three experimental groups completed a six-week VFE protocol and practiced twice daily. The low dose group performed each exercise once, the traditional group twice, and the high dose group four times. Results indicated significant change in VFE MPT for all three groups and higher goal attainment in the high dose group. Low doses appear insufficient to produce substantial change in voice production. Acoustic MPT improved most in the traditional dosage group, which also exhibited best maintenance and best overall outcomes. No toxic effects in vocal fold condition or phonation were observed or measured secondary to high VFE exposure.

The primary purpose of this investigation was to explore the effects of varying degrees of vocal tract semi-occlusion in Vocal Function Exercises (VFEs) on attainment of pre- established maximum phonation time (MPT) goals in individuals between the ages of 18 and 45 with normal voice. Individuals were randomized into three experimental groups: the traditional VFE with a semi-occluded vocal tract (SOVT), modified /o/ with partial occlusion, and modified /a/ without significant occlusion. For six weeks, the participants completed the four exercises two times each, twice daily on corresponding vocal tract postures assigned by group. Results indicated significant change in percent of MPT goal attained for the traditional VFE group. Neither modified vocal tract group resulted in significant change. Decreased occlusion appears insufficient in producing substantial change in voice production despite increased compliance compared to the traditional VFE group.