The terrifying link between Parkinson’s and dementia

If there’s anything worse than Alzheimer’s disease, it has to be Parkinson’s and dementia. Not that Alzheimer’s isn’t pretty bad itself –which it is-, but with it, the dementia part is kind of a given. However, when it comes to Parkinson’s disease you have enough to deal with in the form of the physical symptoms –including tremors, slowed movement, rigid muscles, impaired posture and balance, loss of automatic movements, and speech and writing changes- to also have to face mental deterioration. The truth is though, that Parkinson’s disease dementia is closely related to Alzheimer’s and other types of dementia like Lewy body.

So what exactly is the relationship between Parkinson’s disease and dementia? This condition occurs as result of several changes in the brain, two of which are the disappearance of the nerve cells that make a chemical known as dopamine, and the appearance of clusters of microscopic substances known as Lewy bodies. People with Lewy bodies and Parkinson’s also tend to have plaques and tangles; abnormal structures suspected of killing nerve cells, and which are characteristic of Alzheimer’s. These changes affect the areas of the brain that control movement. Hence, even though the most common early symptom of Parkinson’s disease is a tremor in one hand, the problem lies not in the hand but in the brain. And since the brain is the organ that does all the thinking and reasoning, it should not come as a surprise that as the disease progresses and worsens, the patient’s cognitive and behavioral faculties start to decline.

As intertwined as they are, Parkinson’s dementia and Lewy body dementia are often diagnosed separately, according to the following protocols:


Parkinson’s disease dementia

Lewy body dementia

When dementia symptoms appear only a year or more after a patient has been diagnosed with Parkinson’s based on movement symptoms

When symptoms consistent with Lewy bodies appear first, when both dementia and movement symptoms are present at the time of diagnosis, or when movement symptoms appear within a year of a Lewy body dementia diagnosis


Nevertheless, the belief that the both types of dementia are the two sides of the same coin has been becoming more and more widespread. In any case, it has been estimated that 50%-80% of people with Parkinson’s will ultimately develop dementia as part of the progression of the disease in a span that averages approximately ten years. When a person has Parkinson’s disease dementia, he or she will display some or all of the following symptoms:

  • Thinking difficulties.
  • Depression.
  • Memory, judgment, and concentration changes.
  • Difficulty interpreting visual information.
  • Visual hallucinations.
  • Delusions and paranoia.
  • Irritability and anxiety.

Since an individual with Parkinson’s and dementia not only may have trouble speaking and communicating; be unable to solve problems and understand abstract concepts, forgetful, confused, and distracted; and have difficulty paying attention, but also may experience common complications of Parkinson’s disease like swallowing problems, sleep disorders, and bladder problems, they are more than likely to need a caregiver. Now we all know the toll of Alzheimer’s on caregivers, but we also know how challenging and rewarding it can be, and the same applies for people who care for Parkinson’s patients who develop dementia. Some of the measures a person who cares for a relative or friend with Parkinson’s can take include:

  • Learning as much as they can about the condition in general, and how it can affect their loved one in particular.
  • Communicating honestly and openly with the patient in order to reassure them that they can still have a long and full life. It’s important to do this in the early stages of the disease; while it’s not certain that the person will indeed develop dementia, they should be aware of that possibility so that they can get their affairs in order (i.e., preparing a will) while they still have control of their faculties.
  • Finding means of transportation should the patient not be able to drive anymore.
  • Setting up a schedule for meals and medication.
  • Breaking down tasks –even simple ones- into smaller steps, without worrying about time or the success of execution.