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Parkinson's Dementia: From Motor Function to Cognition & Protein Deposits

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As mentioned in the previous article on Lewy Body Dementia (LBD), Parkinson's Disease Dementia (PDD) shares the causative factor of abnormal alpha-synuclein deposits--also called Lewy Bodies. There are, however, significant differences in presentation from onset to progressive stages.

Symptoms & Diagnosis

Unlike LBD, Parkinson's Dementia (PDD) first manifests as motor symptoms, including:

  • Tremors

  • Muscular stiffness

  • Rigidity

  • Problems with balance

  • Loss of mobility

  • Retarded movement

These characteristics at onset provide a clear enough picture for healthcare providers to make a diagnosis of Parkinson's Disease. A diagnosis of Parkinson's Disease Dementia (PDD) is validated when cognitive decline begins at least a year after onset of physical symptoms. Symptoms of the cognitive decline associated with PDD include:

  • Memory loss

  • Visual difficulties

  • Deficits in concentration and judgment

  • Speech dysfunction--especially muffled speech

  • Depression

  • Irritability and anxiety

  • Sleep disturbances--especially REM Sleep Disorder

  • Delusions and/or visual hallucinations

Treatment & Prognosis

There are currently pharmaceutical regimens available to treat the symptoms of Parkinson's Disease Dementia (PDD). The major challenge with these options is that the use of antipsychotics and medication designed to mitigate movement symptoms may result in hypersensitivity on the part of patients. Additionally, the use of these options must be carefully monitored because these pharmaceuticals--especially when used in combination--may serve to aggravate or heighten other symptoms.

Parkinson's Disease Dementia falls into the category of progressive diseases. This means that the disease will get worse over time, eventually resulting in death; however, the rate of progression is highly variable and as individual as the patient.


Lists in this article adapted from Earlstein, F. (2016). Dementia Facts & Information. NRB Publishing: Nevada.

For more resources and references on Parkinson's Disease Dementia, see the following:

Parkinson's Disease News & Research:



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