The Acoustic Voice Quality Index (AVQI) in People with Parkinson’s Disease Before and After Intensive Voice and Articulation Therapies: Secondary Outcome of a Randomized Controlled Trial

The Acoustic Voice Quality Index (AVQI) in People with Parkinson’s Disease Before and After Intensive Voice and Articulation Therapies: Secondary Outcome of a Randomized Controlled Trial

Gemma Moya-Galé, Ph.D., CCC-SLP, Jennifer Spielman, M.M., M.A., CCC-SLP, Lorraine Ramig, Ph.D., CCC-SLP, Luca Campanelli, PH.D., Youri Maryn, Ph.D.

What is it about?

This study presents the first randomized controlled trial (RCT) examining the effects of two speech treatment approaches, LSVT LOUD and LSVT ARTIC, on voice quality in individuals with Parkinson’s disease (PD). Both treatments were identical in how intensive they were, but LSVT LOUD targeted healthy loudness, whereas LSVT ARTIC focused on articulation. Additionally, an untreated group of individuals with PD also participated in the study, and a group of 20 individuals without PD were included to examine differences in voice quality at pre-treatment.

Individuals with PD were randomized to three groups: 23 received LSVT LOUD, 20 received LSVT ARTIC and 22 did not receive treatment. Voice quality was measured using the Acoustic Voice Quality Index (AVQI; Barsties & Maryn, 2016), which is an objective measure of dysphonia. Additionally, loudness levels were also measured to examine the relationship between this variable and voice quality. Our findings showed that LSVT LOUD led to greater improvements in voice quality and that those gains were actually maintained for at least 6 months after completion of treatment. A relationship between voice quality and loudness was also observed.

Why is it important?

Many people with PD suffer from problems with voice quality, such as hoarseness, which impacts the way they may be understood by others. Findings from this study showed that the voice-focused treatment of LSVT LOUD improves voice quality in people with PD and that those gains are maintained over time. Therefore, we can say that targeting the glottal source directly helps improve the way voice sounds in this population.


For additional perspectives on this treatment study and line of treatment research, we asked lead author of this study Gemma Moya-Galé, Ph.D., CCC-SLP a few questions. Her insights are provided below.

Why did you want to explore this topic?

The efficacy of LSVT LOUD to improve different areas of voice and speech (as well as language and other variables) affected in individuals with PD has been well established. The domain of voice quality, however, was still relatively underexplored, despite the importance that good voice quality may have in communication. This is why we wanted to investigate the effects of LSVT LOUD on voice quality. Additionally, we wanted to examine whether potential benefits on voice quality were the result of the intensive mode of treatment or, rather, whether it was the target of treatment that played a major role. This is why this study also examined the effects of another speech treatment, LSVT ARTIC, which duplicated all aspects of LSVT LOUD, but targeted articulation instead.

What were the key take away points from this study?

The main take away from our study is that LSVT LOUD, which works directly on the glottal (voice) source, leads to greater gains in voice quality compared to an intensive speech treatment that focuses on articulation. Furthermore, not only are gains in voice quality observed immediately post-treatment in the LSVT LOUD group, but improvements were maintained after six months. For those who did not receive treatment, no changes pre-to-post treatment were noted. 

“This study is the first to evaluate the impact of intensive speech and voice treatments on voice quality in Parkinson’s disease in a Randomized Control Trial (RCT). The work of this team of speech clinicians and scientists, led by Professor Moya-Galé, makes an important contribution to documenting short and long-term improvements in voice quality as measured by AVQI following intensive voice treatment. These findings further advance our knowledge of the underlying mechanism associated with successful treatment outcomes in Parkinson’s disease.”

– Dr. Lorraine Ramig, Chief Scientific Officer and Co-Founder, LSVT Global, Inc.

How might this impact SLPs who are working people with Parkinson Disease?

This study provides SLPs with the evidence base to choose to implement LSVT LOUD when working with speakers with PD who evidence signs of dysphonia. 

Were there any surprises or unexpected outcomes you learned?

As we had hypothesized, based on the treatment target of LSVT LOUD, our study supports the delivery of this voice-focused treatment when working on dysphonia in people with PD. Our results, therefore, expand previous evidence of positive effects of LSVT LOUD on voice quality in this population (Alharbi et al., 2019; Cannito et al., 2016).

What happens next in terms of your research on LSVT LOUD and Parkinson’s?

This study focused on an acoustic measure, the AVQI, to quantify treatment-related changes in voice quality. Comparing this objective variable with naïve listeners’ perceptual impressions of voice quality would be the next immediate step.

About the Author

Gemma Moya-Galé, Ph.D.

Dr. Gemma Moya-Galé received her B.A. in English Linguistics and M.A. in Applied Linguistics and Second Language Acquisition from the University of Barcelona. She received her M.S. in Speech-Language Pathology at Teachers College, Columbia University, following a Fulbright Scholarship, and completed her Ph.D. at Columbia University. Her dissertation focused on the effects of LSVT LOUD on conversational intelligibility in Spanish speakers with Parkinson’s disease. Dr. Moya-Galé’s primary research area is speech treatment efficacy for populations with motor speech disorders, particularly for individuals with Parkinson’s disease and cerebral palsy. Dr. Moya-Galé is especially interested in the examination of intelligibility deficits and the relationship between those and acoustics in these populations.