What are the effects of Parkinson's disease on speech?

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Last updated: May 9, 2025View editorial policy

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From the Guidelines

Speech therapy, specifically the Lee Silverman Voice Therapy method, is the most effective treatment for speech problems in individuals with Parkinson's disease. Parkinson's disease often affects speech, causing it to become soft, monotone, slurred, or rapid. This is because Parkinson's affects the muscles used for speaking and the brain's ability to coordinate speech movements 1.

Treatment Options

  • Speech therapy is the primary treatment, focusing on exercises to improve volume, articulation, and breath control, with therapies typically involving 16 sessions over four weeks, with daily home practice.
  • Medications that treat other Parkinson's symptoms, such as levodopa (Sinemet), may help speech by reducing overall motor symptoms, though they don't specifically target speech problems.
  • Deep brain stimulation surgery can sometimes worsen speech while improving other symptoms.
  • Assistive devices like voice amplifiers or speech-generating apps can help when communication becomes difficult.

Importance of Early Intervention

Early intervention with speech therapy is most effective, so patients should seek evaluation as soon as speech changes are noticed rather than waiting until communication becomes significantly impaired 1. Voice therapy has been demonstrated to be effective for dysphonia across the life span from children to older adults, and it is the first line of treatment for vocal fold lesions, such as vocal nodules, polyps, or cysts 1.

Recommendation

The Lee Silverman Voice Therapy method is the most effective method of treating speech problems in individuals with Parkinson's disease, and it should be considered as the primary treatment option 1.

From the Research

Speech Impairments in Parkinson's Disease

  • Voice and speech impairments are present in nearly 90% of people with Parkinson disease and negatively impact communication and quality of life 2.
  • Speech and voice difficulties in Parkinson's disease include impaired articulation and reduced loudness 3.
  • The production of speech depends upon the coordination of various motor activities: respiration, phonation, articulation, resonance, and prosody 4.

Treatment of Speech Impairments in Parkinson's Disease

  • The Lee Silverman Voice Treatment (LSVT) LOUD has been shown to improve vocal loudness and functional communication in people with Parkinson disease 2, 3, 5.
  • LSVT LOUD has been demonstrated to improve associated outcome variables, including speech rate, monotone, voice quality, speech intelligibility, vocal fold adduction, swallowing, facial expression, and neural activation 2.
  • There is insufficient evidence to support or refute the efficacy of any form of speech and language therapy over another to treat speech problems in patients with Parkinson's disease 3.
  • Levodopa's effect on quality of speech is inconclusive, and no data are currently available for late-stage Parkinson's disease 6.

Management of Speech Disorders in Parkinson's Disease

  • Treatment modalities for speech disorders in Parkinson's disease include pharmacological intervention, speech therapy, surgery, deep brain stimulation, and vocal fold augmentation 4.
  • Speech treatment in Parkinson's disease should be part of a multidisciplinary approach to patient care in this disease 4.
  • Despite the high prevalence of speech disorders in Parkinson's disease, only 3-4% receive speech treatment 4.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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