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About Alzheimer's & Dementia

Types of dementia Parkinson's Disease Dementia

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What is Parkinson’s Disease Dementia?

Parkinson's Disease Dementia (PDD) refers to a decline in thinking and reasoningthat eventually affects a number of people with Parkinson's disease. Parkinson's disease is a fairly common neurological disorder, estimated to affect nearly 2% of people older than age 65 years of age. It is estimated that 50 – 80% of those with Parkinson's disease eventually experience Parkinson's disease dementia. The average time from onset of Parkinson’s disease to developing dementia is about 10 years.
 
The brain changes linked to Parkinson's disease and Parkinson’s Disease Dementia (PDD) are irregular, tiny deposits of alpha-synuclein protein called Lewy bodies. Lewy bodies are also found in several other brain disorders, including Lewy Body Dementia. Evidence suggests that Lewy Body Dementia, Parkinson's disease and PDD may be linked to the same underlying changes in brain processing. In fact, many experts believe that Parkinson’s Disease Dementia and Lewy Body Dementia are two different outcomes of the same underlying problems with brain processing -  but most experts recommend continuing to diagnose them as separate disorders. Another puzzling factor is that many people with these two types of dementia also have the common features of Alzheimer's disease – plaques and tangles in brain nerve cells.

What changes can I expect?

Common symptoms include: changes in memory, concentration and judgement; problems with visual perception; muffled speech; visual hallucinations; delusions or paranoia; depression; irritability and anxiety, and sleep disturbances, including excessive daytime drowsiness and rapid eye movement (REM) sleep disorder. Like other types of dementia, PDD may get worse over time and the speed of progression can vary from individual to individual.

What are the risk factors?

Certain factors at the time of Parkinson's disease diagnosis may increase a person’s future risk of developing dementia - including older age, greater severity of motor symptoms and having mild cognitive impairment. Additional risk factors may include: hallucinations in a person who doesn't yet have other dementia symptoms; excessive daytime sleepiness; postural instability and gait disturbance (PIGD) which includes "freezing" in mid-step, difficulty initiating movement, shuffling, problems with balance and falling.

How is it diagnosed?

Unfortunately, there is currently no single test, or combination of tests, that conclusively determines the presence of Parkinson’s Disease Dementia (PDD). Guidelines for diagnosing PDD and Lewy Body Dementia are:
  • The diagnosis is PDD when a person is originally diagnosed with Parkinson's based on movement symptoms and dementia symptoms don’t appear until one year (or more) has passed
  • The diagnosis is Lewy Body Dementia when 1) Dementia symptoms consistent with Lewy Body Dementia develop first; 2) Both dementia symptoms and movement symptoms are present at the time of diagnosis; and 3) When movement symptoms develop within a year of Lewy Body Dementia diagnosis.
Since individuals with Parkinson's disease are at a higher risk for dementia as their disease progresses, doctors monitor those with Parkinson's closely for signs of changes. When someone with Parkinson's disease develops changes in thinking, doctors often request a magnetic resonance imaging (MRI) scan of the brain to rule out tumors, structural changes and evidence of vascular disease.

What kind of treatment is available?

There are currently no treatments to slow or stop the brain cell damage caused by Parkinson’s Disease Dementia (PDD). Current treatment strategies focus on alleviating or managing the symptoms.
Treatment considerations involving medications might include the following:
  • Cholinesterase Inhibitors, a common approach to treating Alzheimer's disease and could also assist with PDD symptoms. Antipsychotic drugs should be used with extreme caution in PDD, since they may cause serious side effects in as many as 50% of those with PDD and Lewy Body Dementia. Side effects may include sudden changes in consciousness, impaired swallowing, acute confusion, episodes of delusions or hallucinations, or the appearance of worsening Parkinson's symptoms.
  • L-dopa may be prescribed to treat Parkinson's movement symptoms, but is thought to aggravate hallucinations and confusion in those with PDD and Lewy Body Dementia.
  • Antidepressants may be used to treat depression, which is common in both PDD and Lewy Body Dementia.
  • Clonazepam may be prescribed to treat REM sleep disorder.
Source: www.alz.org

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  • Brain diagram

    A visual map of the brain lobes and their functions