Dysprosody - Parkinson's Disease and Dysprosody

Parkinson's Disease and Dysprosody

Parkinson's disease, or sometimes referred to as PD, is a chronic neurodegenerative disorder that involves the loss of dopaminergic neurons in the brain. While common symptoms of PD are tremors, rigidity, bradykinesia, and postural instability, dysprosody is also a common issue in individuals diagnosed with PD. A common characteristic feature of dysprosody in Parkinson's is monopitch, or an inability to vary pitch when speaking.

Several studies have been performed investigating the link between Parkinson's and dysprosody. They have concluded that PD patients tend to struggle with specific areas of prosody; Parkinson's patients are less able to produce the loudness, pitch, and rhythm patterns required for expressing certain emotions, such as anger. In general, the voice modulations needed to express strong emotions are particularly difficult for PD patients. Because they generally have normal abilities to appreciate vocal or visual emotion presented to them, this inability to vocally express emotion has been linked to dysprosody and not the actual processing of emotions. Abnormal pauses in speech are also a characteristic of Parkinsonian dysprosody, including both pauses in general speech and intra-word pauses. A decrease in speech rate can also be observed in Parkinson's patients.

Studies have also shown a progression of dysprosody in patients with PD over time. Abnormalities in speech rate, pauses, and variation range in speech become worse as the disease progresses. It is important to note the degradation of prosody in PD over time is independent of motor control issues, and is thus separate from those aspects of the disease. Studies have shown that normal treatment for PD can help with the dysprosody symptoms, however there is usually an improvement in pitch control only and not in the volume and emotional aspects of the disease. These treatments include medications such as L-DOPA as well as electrophysiological treatments.