New Research
Tripoliti, E., Tsuboi, T., Barbe, M.T., Sousa, M., Barkmeier-Kraemer, J., Jergas, H., Arno, G., Buie, N., Day, M., Krýže, P., Nelson, J.R., Warren, A.E.L., Rahimpour, S., Rusz, J., Krack, P. and Simonyan, K. (2026), Speech and Deep Brain Stimulation in Parkinson’s Disease, Essential Tremor, and Dystonia: A Systematic Review and Meta-analysis. Mov Disord. https://doi.org/10.1002/mds.70322
For perspectives on this newly published treatment study, we asked one of the authors, Elina Tripoliti, SLT, PhD, a few questions. Her insights are provided below.
What is this study about?
Deep brain stimulation (DBS) can be an effective treatment for motor symptoms of patients with Parkinsons, Essential Tremor and Dystonia. However there have been mixed reports in the literature about its effects on speech, and the factors that contribute to speech changes post DBS.
This paper aimed at reviewing systematically the literature on speech and DBS for patents with Movement disorders. The meta-analyses showed that subthalamic nucleus DBS resulted in poorer speech intelligibility compared with best medical treatment, particularly when on medication. For patients with Essential tremor DBS suppressed vocal tremor but increased the risk of dysarthria. Dystonia outcomes showed greater heterogeneity.
Why is it important?
There are 3 issues that are relevant to speech clinicians: First, patients undergoing DBS need to be recorded before and after the procedure, by a speech clinician- part of the DBS multi-disciplinary team. Second, sustained phonation is not as sensitive nor as useful an assessment task as “connected speech”; and third there is a need for therapy studies for patients undergoing DBS: there are only two papers published that showed the complexity of speech rehabilitation post DBS.
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.
Why did you want to explore this topic?
I have been working with patients undergoing DBS since 2002, under the mentorship of Prof Marwan Hariz and Prof P Limousin. They were absolute advocates of meticulous and accurate reporting of patient-DBS outcomes, and they supported my research and clinical passion in this area.
What are key take away points from this study?
As mentioned above, working in a team and always take a pre-operative recording to compare before and after. Patients go through a lot of changes in the medication and stimulation and a reliable recording to track progress is paramount. They are also usually in the more advanced stages of the disease so maintaining communication abilities is vital for their survival.
How might this impact clinicians (SLPs) who are working with this population?
Hopefully it will point towards the gaps in our knowledge and clinical practice such as therapy strategies, proper standardized methodology for speech recordings, more multidisciplinary working and so on.
Were there any surprises or unexpected outcomes you learned?
We called this project Sisyphus, after the Greek demi-God who cheated death twice. Zeus gave him immortality but punished him to carry a boulder up the mountain only for the rock to roll back down again forever. This was a challenging project for the “messy” state of literature we have in speech studies. Diversity can be good for pluralism and new ideas, but it is not easy to get a consensus.
What happens next in terms of your research on this topic?
The most intriguing aspect of speech and DBS is its effects on dysfluencies and the effect of thalamic pathways on dysfluent stuttering-like speech. I would like to investigate further the role of the thalamus and basal ganglia on acquired dysfluencies.
We are also trying to find funding for a project to develop a therapy program for speech, gait and balance post DBS.
