Immediate and long-term effects of speech treatment targets and intensive dosage on Parkinson’s disease dysphonia and the speech motor network: Randomized controlled trial
Shalini Narayana, PhD, Crystal Franklin, MS, Elizabeth Peterson, MA, CCC-SLP, Eric J Hunter, PhD, Donald A Robin, PhD, CCC-SLP, Angela Halpern, MS, CCC-SLP, Jennifer Spielman, MA, CCC-SLP, Peter T Fox, MD, Lorraine O. Ramig, PhD, CCC-SLP
What is it about?
This study looked at speech and brain changes in individuals with Parkinson’s disease following two speech treatment approaches, matched for intensity of dosage (16, 1-hour individual sessions in one month) but differing on treatment target, loudness (LSVT LOUD) or articulation (LSVT ARTIC). A group of untreated individuals with Parkinson’s disease were also studied as a comparison group. All participants were evaluated at baseline, post-treatment (one month after baseline), and seven months after baseline to help identify both short-term and long-term changes.
Why is it important?
Nearly ninety percent of individuals with Parkinson’s disease will develop speech and voice difficulties, which can result in greatly reduced communication. Presently, the most effective treatment for voice and speech disorders in individuals with Parkinson’s disease is LSVT LOUD. While a few other brain imaging studies have been conducted following LSVT LOUD and found increased activity in motor and auditory regions of the speech motor network, it is unclear if changes in activation were due to the target of treatment or intensity of dosage. This is the first LSVT LOUD brain imaging study to include a comparison of a treatment group and an untreated group, which allows us to better understand if brain changes are related to intensity of dosage or the target of treatment (loudness vs. articulation). Additionally, it is the first LSVT LOUD brain imaging study to follow participants out to seven months, which helps us better understand if the treatment approaches result in long-term effects without any additional treatment.
Read the full study HERE.
Perspectives
For additional perspectives on this treatment study and line of treatment research, we asked co-authors Lorraine Ramig, Ph.D., CCC-SLP and Elizabeth Peterson, MA, CCC-SLP, a few questions. Their insights are provided below.
Why did you want to explore longer term affects of speech treatment targets?
The overarching goal of the study was to determine if behavioral voice and speech treatment approaches can improve communication challenges faced by individuals with Parkinson’s disease and if these improvements can have immediate and lasting effects at the level of the brain. This knowledge can help us determine the best methods for voice and speech treatment for individuals with Parkinson’s disease, in turn improving their quality of life. While there is a body of research that supports changes in brain activation following LSVT LOUD, we wanted to understand changes that differing behavioral speech treatment approaches can have on the brain, and if these changes are related to the target of treatment and/or intensity of dosage. Additionally, we wanted to explore if changes that we see last over time, so participants were followed out to seven months.
What were the key take away points from this study?
To better understand if the treatment approaches made a difference behaviorally, we first analyzed speech changes, using a measure of voice quality, Smooth Cepstral Peak Prominence (CPPS). CPPS is a common measure used in research and clinical evaluation of voice disorders; the measure highly correlates to the perception of voice quality. Results show that only the LSVT LOUD group had significant improvements in CPPS values at post-treatment, and these results were maintained out to seven months. Changes in CPPS in the LSVT LOUD group were significantly larger than any changes in CPPS for the LSVT ARTIC and untreated groups. Therefore, we can conclude that LSVT LOUD was effective in improving voice quality, and likely then improved listener preference or even improved intelligibility, as measured by CPPS. Additionally, the magnitude of change we saw in CPPS in the LSVT LOUD group is comparable to treatment effects of LSVT LOUD we have published in previous studies using other speech measures.
Next, we wanted to explore if there were changes in brain activation following either or both treatment approaches, and if these changes lasted over time, so we studied changes in cerebral blood flow using positron emission tomography (PET) imaging, during a reading task. The areas we looked at were the dorsal premotor cortex, articulatory and laryngeal motor cortices, and the auditory cortices. These regions of the brain are engaged during speech initiation and articulation, including control of mouth, face, and voice muscles, and breathing and monitoring feedback.
There were many exciting imaging findings. First, we found increased activity in the right side of the motor and premotor areas at post-treatment following both LSVT LOUD and LSVT ARTIC. This right-sided activation pattern indicates that the intensive nature of treatment delivery caused changes in the short-term, likely representing a critical phase in skill learning.
Figure Legend
Changes in brain activation in individuals with Parkinson’s disease following intensive voice treatment (LSVT LOUD) and intensive articulation treatment (LSVT ARTIC). LSVT LOUD (yellow) targeted the voice box and respiration while LSVT ARTIC (blue) targeted the mouth and lips. Brain areas changed following LSVT LOUD are shown in yellow and brain areas changed following LSVT ARTIC are shown in blue. Left hemisphere (LH) activations are solid and right hemisphere (RH) activations are checkered. LSVT LOUD increased activity in the left premotor cortex and both auditory cortices while LSVT ARTIC increased activity in both premotor cortices and the left insular cortex.
Next, we saw right auditory cortex activation increased at post-treatment only following LSVT LOUD. This finding likely correlates to LSVT LOUD participants’ new awareness of the amount of loudness and effort needed to produce a voice that others can easily hear and understand. This finding supports generalization of the treatment effect into everyday living.
When we looked at the imaging data at seven months, we found that the activation patterns were normalized to the left side of the brain for only LSVT LOUD. This change may represent long-term normalization of the activity to the dominant hemisphere, indicating successful skill retention and shows us that intensity of dosage and a target of loudness may be critical for long-term success.
Finally, when looking at the brain changes in the untreated group, we saw progressive decrease in activity of pre-motor and motor cortices, and right auditory cortex, along with continued weak activity in the left auditory cortex. These changes represent a weakening speech motor system and unsuccessful methods of compensation for these weaknesses.
What does this tell us? If individuals with Parkinson’s disease don’t “use it”, they “lose it”. Or better yet, “use it to improve it”! Early intervention matters! This decrease and continued weak activity were only over the course of seven months. The earlier speech-language pathologists can intervene with intensive voice treatment, the better!
Lorraine, as the Principal Investigator on the National Institutes of Health (NIH) funding for this project, describe the impact.
For many years our vision has been to understand the neural bases of LSVT LOUD for Parkinson’s disease given the positive and dramatic changes following treatment. This study goes a step beyond our previous work, by adding a comparative treatment and an untreated control group, all studied out to 6 months follow-up. Frankly it is a ‘dream design’ that allows us to begin to understand neural mechanisms underlying speech treatments with different targets and to understand what happens without treatment. The findings remind us of the value of intensive dosage voice treatment, the critical role of the auditory system in positive treatment outcomes in PD and the need to treat patients as early as possible to avoid deterioration. Our wonderful team has made a superb contribution that motivates future work!!
Elizabeth, how might this impact SLPs who are working people with Parkinson Disease?
As the treating speech clinician, it is exciting to see that changes occurred at the neural level to support the behavioral changes in voice and speech that I saw after treating the participants in the study. Two key takeaways for speech clinicians are: 1) Intensive dosage really matters; the changes in voice and speech and neural activation support this; and 2) the earlier we treat individuals with PD the better. It was discouraging to see the decreased and continued weak activity in neural activation patterns for the group who did not receive treatment during the study, especially when compared to the changes in activation in both treatment groups – there is so much potential for change! Speech clinicians should have confidence in delivering intensive treatment and requesting support as needed from administrative personnel to make this possible. You can make such a difference in an individual’s quality of life by advocating for and delivering intensive treatment.
Were there any surprises or unexpected outcomes you learned?
We were surprised to see changes in activation in the right side of the brain for motor and pre-motor areas following LSVT ARTIC since this group did not demonstrate significant changes in the speech analysis. One explanation may be that CPPS is not sensitive to the changes occurring following articulation training. Because of this unexpected finding, we conducted a preliminary speech analysis to measure potential changes in articulation. This was done by calculating the energy of speech productions in a pitch range of 1000-3000 Hz, which is considered the most sensitive hearing range for humans. Increased energy in this range has previously been shown to correlate with articulation changes leading to improvements in intelligibility (Krause & Braida, 2004). Our findings show a significant increase in energy in this pitch range at post-treatment for LSVT LOUD and LSVT ARTIC, but not the untreated group. Additionally, the increases in energy were maintained out to seven months in only the LSVT LOUD group. This preliminary speech analysis suggests improvement in articulation for the LSVT ARTIC and LSVT LOUD group directly following treatment, which may help explain why we saw a right-sided pattern in activation of the motor and pre-motor areas directly following both treatment approaches. Because the LSVT ARTIC group did not maintain any behavioral speech improvements out to seven months, this may explain why we did not see the same shift in activation patterns to the left side that we saw at seven months following LSVT LOUD. We would like to conduct future research to investigate this finding more systematically.
What happens next in terms of your research on LSVT LOUD and Parkinson’s?
In addition to investigating other speech measures as mentioned above, we would also like to continue this research with a larger group of participants to see if the findings are repeated on a larger scale.
To hear more from co-author Elizabeth Peterson, MA, CCC-SLP on this exciting new published study, watch this video!
About the Author
Elizabeth Peterson M.A., CCC-SLP
Ms. Peterson received her master’s degree in Speech, Language and Hearing Sciences from the University of Colorado-Boulder. She has worked as a research associate at the National Center for Voice and Speech-Denver and the University of Texas Health Science Center, San Antonio. In her current role with LSVT Global, Ms. Peterson serves as an LSVT LOUD Faculty Instructor and manages their ongoing webinar program to educate allied health professionals, individuals with PD or other neurological conditions, and all others involved in their care on topics related to neurogenic voice and speech disorders and the LSVT programs.
Lorraine Olson Ramig Ph.D., CCC-SLP
Professor Ramig received her PhD at Purdue University. She has been a Professor at the University of Colorado-Boulder and Senior Scientist at the National Center for Voice and Speech-Denver. Today she is the Chief Scientific Officer and Co-Founder of LSVT Global-Tucson. Professor Ramig has been the Principal Investigator for over 20 years on studies of the efficacy of voice treatment for Parkinson’s disease though funding from the National Institutes of Health (NIH) resulting in hundreds of publications including five randomized control trials (RCTs). She is also an LSVT LOUD faculty instructor. Professor Ramig has received Honors of the Association, the highest award given from ASHA.