Peer-reviewed research
Speech treatment in Parkinson's disease: Randomized controlled trial (RCT)
Lorraine Ramig et al., Movement Disorders, 2018 · DOI 10.1002/mds.27460
Read the originalRead on October 16, 2026
- What it is
- A randomized controlled trial comparing two intensive speech treatments (LSVT LOUD for voice and LSVT ARTIC for articulation) for people with Parkinson's disease. Its background states how common speech disorders are in Parkinson's disease.
- How much weight it carries
- Peer-reviewed, open access in PubMed Central. The 89 percent figure is cited background from earlier studies rather than a result of this trial, and it is an upper estimate ('as many as').
Facts taken from this source
- As many as 89 percent of people with Parkinson's disease develop speech disorders.
“As many as 89% of people with Parkinson's disease (PD) develop speech disorders.” (Abstract, Background)