Parkinson’s and Alzheimer’s: Sorting Out These Often-Confused Illnesses


Alzheimer’s and Parkinson’s disease have confused many people, including scientists. For years, research had linked genetic causes of the two diseases. But a new study by the Cardiff University School of Medicine in Wales “found no evidence of common genetic regions that increase the risk of both illnesses,” according to research published in the Journal of the American Medical Association (JAMA), Neurology.

Whether or not the underlying causes of these diseases have similar roots or not, what makes them so similar? And how can you tell the difference?

The good news is that the early stage symptoms of both diseases are so different, a physician is not likely to confuse them. Unfortunately, both diseases share similarities with other diseases, which can lead to misdiagnoses, and there is, so far, no definitive test for either Alzheimer’s or Parkinson’s.

Public perception about both diseases, however, can lead to additional frustrations for sufferers. Let’s look at some of the similarities and some of the differences. By being more informed, we are all in a better position to offer support to those who are battling these diseases.

Similarities Between Alzheimer’s and Parkinson’s

  • Both diseases typically afflict older people, although 200,000 Americans have early onset Alzheimer’s, which typically strikes people in their 40s and 50s, and between 150,000 and 250,000 people with Parkinson’s are under the age of 50.
  • Dementia is a symptom of both diseases, although dementia appears in later stages of Parkinson’s (anywhere from one to 10 years or more from the onset) and is one of the defining characteristics of Alzheimer’s
  • The diseases share other symptoms, including difficulties sleeping and trouble with speech, as well as mood changes, most commonly depression
  • Autopsies reveal the brains of those with both Parkinson’s and Alzheimer’s show plagues and tangles
  • There is no definitive test for either illness; doctors evaluate your symptoms, results of neurological testing and even how victims respond to certain treatments to reach a diagnosis

Differences Between Alzheimer’s and Parkinson’s
While it may seem, on the surface, that these diseases are very similar, Parkinson’s typically manifests first in physical ways. The cardinal symptoms of Parkinson’s include resting tremors, balance problems, rigidity, slow movement and reduced facial expression. Non-physical symptoms do show up, and these are similar to Alzheimer’s symptoms, including memory loss, depression and anxiety.

While memory loss and dementia doesn’t show up in Parkinson’s patients until one to 10 years or more after the diagnosis, memory loss and confusion are the cardinal symptoms of Alzheimer’s disease. Let’s look at a few other ways these diseases are different.

  • Early onset Alzheimer’s typically doesn’t occur until middle age. Young onset Parkinson’s is diagnosed as early as 21.
  • Alzheimer’s disease is fatal, as the disease destroys brain cells. However, sufferers are more likely to die from symptoms or complications of Alzheimer’s than the disease itself. With Parkinson’s, as it states on the Michael J. Fox Foundation website (, “You will die with Parkinson’s disease, not from it.” As with Alzheimer’s, patients are more likely to die from a fall, aspiration, pneumonia or any number of complications as the disease progresses.

While researchers aren’t close to finding a cure for either disease, early diagnosis is a key to treatments that can slow the progression. Awareness is important; understanding the similarities and differences helps caregivers, friends, family and even acquaintances do and say the right things to make life easier and happier for those suffering from these illnesses.