New Research
Shakeela Saleem, Anna Miles & Jacqueline Allen (03 Feb 2025): Effects of LSVT LOUD and EMST in individuals with Parkinson’s disease: A two arm nonrandomized clinical trial, International Journal of Speech-Language Pathology, DOI: 10.1080/17549507.2025.2455635
For perspectives on this newly published treatment study, we asked the authors Shakeela Saleem, PhD, Anna Miles, PhD, and Jacqueline Allen, MD, PhD. a few questions. Their insights are provided below.
What is this study about?
This study looked at two different types of therapy for people with Parkinson’s disease:
- LSVT LOUD® (an intensive voice therapy)
- EMST (a type of breathing exercise that strengthens the muscles involved in forcefully exhaling into a device)
We looked to see how these two therapies affect swallowing, coughing strength, and speaking.
The study included 58 people who had mild to moderate Parkinson’s disease. Each person did four weeks of either LSVT LOUD or EMST, and their swallowing, coughing, and voice were tested before and after the therapy using x-ray imaging, cough strength tests, voice recordings, and questionnaires.
Here’s what we found:
- LSVT LOUD helped more with voice improvements, including louder speech, better pitch control, and more efficient use of the airflow when individuals spoke or made sounds.
- LSVT LOUD also improved function of part of the throat (the pharyngoesophageal segment) that’s important for swallowing.
- EMST helped improve a swallowing movement called hyoid displacement that lifts and protects the airway, making it easier to swallow safely without food or drink going down the wrong way.
- Both therapies helped with voluntary and reflexive cough strength.
- Both therapies made people felt more positive about their voice and swallowing symptoms and feel like their voice and swallow had less of a negative impact on their lives.
Why is it important?
People with Parkinson’s disease often have trouble swallowing and speaking. This can lead to serious problems like choking, chest infections or not getting enough nutrition as well as occupational and social impacts.
This study shows that both LSVT LOUD and EMST are safe and manageable for people with mild to moderate Parkinson’s disease. This study also shows that both LSVT LOUD and EMST can help swallowing, voice and cough, but in different ways. So, people with Parkinson’s disease and their clinicians can choose the right therapy for their needs or use both complimentarily.
Read the full study HERE.
Why did you want to explore this topic?
Our exploration of the effects of LSVT LOUD and EMST on voice, swallowing, and cough functions in people with PD was driven by the growing recognition that these functions share common anatomical and physiological mechanisms. Airway protection, a critical concern in PD, relies on the coordinated activity of the respiratory, laryngeal, and pharyngeal muscles, which also play key roles in swallowing, cough, and voice production. Existing evidence suggests that deficits in one of these areas often correlate with impairments in the others, suggesting that there might be potential spread effects from targeted interventions.
In 2017, we conducted a pilot study that explored the effects of LSVT LOUD on swallowing and cough, finding promising improvements in swallowing biomechanics and cough strength. Building on this, the current study evaluates non-invasive therapies, such as LSVT LOUD and EMST, which are well-established for improving voice and some swallowing kinematic measures, respectively. The goal is to determine whether these treatments can concurrently optimize multiple interrelated functions. The positive results of this study offers valuable treatment options that are cost-effective and efficient, helping to improve patient outcomes and address the challenges of managing Parkinson’s disease.
What are key take away points from this study?
Clinical benefits of LSVT LOUD:
LSVT LOUD significantly improved voice function in people with mild to moderate Parkinson’s disease, including vocal intensity, pitch range, and sustained phonation. It also enhanced airway protection during swallowing by improving the timing of laryngeal closure, helping to prevent aspiration. In addition to its primary speech benefits, LSVT LOUD improved both voluntary and reflexive cough strength, supporting safer airway clearance. Participants reported greater confidence in communication and swallowing. The therapy is non-invasive and can be delivered in-person or via telehealth, making it an accessible treatment option.
Clinical benefits of EMST:
EMST primarily improved swallowing biomechanics, such as hyoid movement and pharyngeal muscle tone, which are crucial for safe and effective swallowing. It also strengthened the muscles used for breathing and coughing, leading to improvements in voluntary cough strength and faster airflow generation. Although voice improvements were limited, participants still reported feeling improvements in their speech and swallowing confidence. EMST is a simple, home-based therapy that is easy to use and well-suited for ongoing self-management of respiratory and swallowing symptoms in people with mild to moderate Parkinson’s disease.
How might this impact clinicians (SLPs) who are working with this population?
- The differing effects of LSVT LOUD and EMST on voice and swallowing allow SLPs to tailor interventions based on individual symptom profiles in PD.
- Telehealth delivery of both treatments remains viable and may enhance access for patients with mobility or travel limitations.
- Even small improvements measured during testing led to meaningful subjective improvements in communication and swallowing confidence, this highlights the relevance of client-centered outcomes in PD care.
Were there any surprises or unexpected outcomes you learned?
Both LSVT LOUD and EMST demonstrated strong treatment adherence, with over 85% of participants completing the full programs. This was made possible through the use of individualized adaptive strategies, including flexible scheduling, visual supports, and family involvement, which helped overcome common barriers such as fatigue, device use difficulties, and access issues.
Importantly, the study found that benefits extended beyond objective clinical measures, participants in both groups reported noticeable improvements in their communication and swallowing abilities, reflecting enhanced confidence and quality of life. These perceived improvements highlight the practical value of both therapies, reinforcing their role as patient-centered, non-invasive solutions for managing speech, swallowing, and airway protection challenges in Parkinson’s disease.
However, some challenges were identified, particularly with the telehealth delivery format, adherence to intensive therapy schedules, and training individuals with cognitive decline or individuals with increased disease severity. These factors may affect engagement and outcomes, especially in more complex cases.
What happens next in terms of your research on this topic?
The next steps in this area of research would be to explore the potential benefits and feasibility of delivering LSVT LOUD and EMST either sequentially or concomitantly. As these therapies target different yet complementary aspects of speech, swallowing and cough function, it is possible that dual therapy may yield synergistic outcomes. However, this has not yet been systematically studied, and questions remain around the tolerability and justification of such exercise loading in people with Parkinson’s disease. We would also like to see how these therapies assist patients with more severe PD.
Learn more about the Swallowing & Voice Research Laboratory at the University of Auckland.
About the Authors:
Dr. Shakeela Saleem, PhD.
Dr. Shakeela Saleem is a research fellow in Speech Science, School of Psychology at the University of Auckland. Specializing in innovative swallowing assessments and management, she focuses on adults with neurodegenerative and neurogenetic conditions, as well as head and neck cancer. Her PhD project featured a two-treatment arm clinical trial aimed at improving voice, swallow, and cough skills in individuals with Parkinson’s disease. Currently, she co-leads a randomized clinical trial evaluating the effects of expiratory muscle strength training on the swallowing function of head and neck cancer patients treated with primary chemoradiation therapy. Shakeela is also experienced in teaching and conducting dysphagia simulation training workshops. She mentors Master of Speech and Language Therapy practice students, guiding them in projects on voice and swallowing assessment and therapy approaches. She is a registered member of New Zealand Speech-language Therapists’ Association. She has experience working as a speech pathologist in acute adult care settings and university-based clinics.
Associate Professor Anna Miles, PhD.
Dr Anna Miles is a practising speech pathologist with 25+ years of experience working in the acute and community setting. Anna is an associate professor at The University of Auckland. She is a researcher, lecturer and clinician in the area of voice and swallowing disorders. Dr Miles has ~150 peer reviewed publications and 2500+ citations. She is the New Zealand Speech-language Therapists’ Association Expert Adviser in Adult Dysphagia, active member of the Dysphagia Research Society and has been awarded ASHA Fellow for her contributions to research, clinical teaching and international service.
Associate Professor Jacqui Allen, MD, FRACS
Associate Professor Jacqueline Allen is a Laryngologist practicing in Auckland, New Zealand. A graduate of the University of Auckland, Dr Allen undertook Fellowship training at the Voice and Swallow Centre, University of California, Davis where she specialized in Voice and Dysphagia utilizing modern in-office techniques, endoscopy and laser surgery. She returned to New Zealand in 2010 and established the Auckland Voice and Swallow Centre, and the Swallowing Research Lab at University of Auckland where these techniques have been put to use. Research interests include neurogenic dysphagia, swallowing and nutrition across the lifespan, vocal fold scar translational research (in which she has completed a doctoral degree), reflux disease and novel engineering modelling for swallow dysfunction. Dr Allen is Past President of Dysphagia Research Society, a Member of the American Bronchoesophagological Association, American Laryngological Association and Laryngology Society of Australasia and is Section Editor of Current Opinion in Otolaryngology and Annals of Rhinology, Otology and Laryngology. She has published more than 100 journal articles, 1 book, and 25 book chapters and is an Editorial Board member and reviewer for many international peer-reviewed journals including Otolaryngology Head and Neck Surgery, European Archives of Otolaryngology and Laryngoscope. She currently lives with her husband and daughter in Auckland.
