Parkinson’s Disease 

Overview:

Parkinson’s Disease (PD) is a progressive neurodegenerative disorder characterized by motor symptoms such as resting tremor, muscle rigidity, bradykinesia (slowness of movement), and postural instability. The disease stems from the loss of dopamine-producing neurons in the substantia nigra of the midbrain, leading to widespread effects on movement and other functions; many patients also experience non-motor symptoms like cognitive changes or mood disturbances. Critically for communication, PD commonly causes hypokinetic dysarthria – a speech disorder marked by reduced loudness, monotone pitch, imprecise articulation, and rapid or mumbled speech – as well as voice difficulties (e.g. a soft, breathy voice). 

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Clinical relevance: 

SLPs work with individuals with Parkinson’s Disease to address speech and voice impairments (nearly 90% of people with PD develop speech/voice issues), using therapies like voice amplification techniques or the Lee Silverman Voice Treatment to improve vocal loudness, clarity, and overall communication.

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Sources:

Poewe, Werner, Katrin Seppi, Christine M. Tanner, et al. “Parkinson Disease.” Nature Reviews Disease Primers 3 (2017). Link

Sapmaz Atalar, M., O. Oguz, and G. Genc. “Hypokinetic Dysarthria in Parkinson’s Disease: A Narrative Review.” Medical Bulletin of Sisli Etfal Hospital 57 (2023). Link