PROJECT SUMMARY / ABSTRACT High-quality research designs have demonstrated that voice therapy has a positive impact on hyperfunctional voice disorders associated with muscle tension dysphonia (MTD). Among the options of behavioral voice therapy for MTD, one of the most effective evidence-based approaches is flow phonation (a.k.a., stretch-and- flow voice therapy). However, the phenomenon of post-treatment outcome measures remaining substantially outside the range of normal is a ubiquitous finding in studies investigating this and other voice therapy approaches. From both a cost burden and quality of life perspective, this phenomenon supports a need to develop and refine voice therapy treatment approaches to promote better outcomes. Vibration is a physical modality that has a historical use in the rehabilitation professions, but only recently has it been scientifically studied as a modality for voice therapy when used by speech-language pathologists. When applied locally on the perilaryngeal surface as a local translaryngeal vibration therapy (LTLV), early research has demonstrated beneficial effects on voice physiology and clinical outcomes. Further high-quality clinical research studies are needed to evaluate the efficacy of LTLV as a modality for voice disorders and to better understand the effects of vibration and effective vibration dose on voice rehabilitation outcomes. The research proposed in this R15 has the potential to transform clinical practice of treatment for MTD, the most common voice disorder among treatment-seeking populations. That potential is vested in the pursuit of three specific aims: (1) determine the clinical efficacy of LTLV as a concurrent treatment using flow phonation voice therapy in patients with MTD, and (2) determine the effect of treatment dose on clinical response associated with treatment outcomes. In addition to the potential impact of this R15, the innovative of approach of using LTLV as a concurrent modality with flow phonation combined with investigation of the most effective frequency parameter for clinical application represents a pioneering approach to advance the field of clinical voice practice in speech-language pathology.