Voice Therapy Improves Speech Disorder Symptoms in Parkinson Disease

Voice treatment, focusing on respiratory-laryngeal subsystem therapy, improved speech disorder symptoms in patients with Parkinson disease, according to a study published in Movement Disorders.

The researchers of this trial randomly assigned 64 patients with mild to moderate Parkinson disease into 1 of 3 arms. One arm implemented a protocol focusing on voice treatment through respiratory-laryngeal subsystem therapy (n=22), one arm implemented a protocol focused on articulation treatment through orofacial-articulatory subsystem therapy (n=20), and the last arm remained untreated (n=22). The researchers did include a group of 20 healthy controls to use as a comparison arm at baseline. Data collection included sound pressure levels during speech and a self-reported Modified Communication Effectiveness Index score. These assessments were measured at baseline, after the 1-month treatment protocol, and at a 7-month follow-up.

At baseline, all 3 arms that included patients with Parkinson disease were similar among all characteristics, and when compared to healthy controls, patients with Parkinson disease had significantly lower sound pressure levels for 4 out of the 6 sounds measured and a significantly worse median Modified Communication Effectiveness Index score (P <.0001). At 1 month, sound pressure levels significantly improved in the voice treatment arm over the other 2 arms (P >.05, both), and Modified Communication Effectiveness Index score significantly improved for both the voice treatment and the articulation treatment over the untreated arm (P =.02, both). At 7 months, the Modified Communication Effectiveness Index score was still significantly improved for the voice treatment arm only (P =.0011).

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Future studies need to increase participant number to increase statistical power, expand the trial to include different severities of Parkinson disease, and use imaging tools to clarify improvements in specific speech mechanisms.

In conclusion, this study indicates that voice treatment focusing on respiratory-laryngeal subsystem therapy shows lasting beneficial improvements to speech for patients with mild to moderate Parkinson disease.


Ramig L, Halpern A, Spielman J, Fox C, Freeman K. Speech treatment in Parkinson’s disease: randomized controlled trial (RCT) [published online September 28, 2018]. Mov Disord. doi: 10.1002/mds.27460