The disease

Parkinson’s is a neurodegenerative disease that mainly affects movement.Unlike many neurological disorders, the abnormality at the root of Parkinson’s is known. It’s caused by cell death in an area of the brain called the “substantia nigra.” The cells produce dopamine, a chemical that functions as a neurotransmitter, sending signals between the brain cells involved in movement.

By the time Parkinson’s is diagnosed, it’s estimated that approximately 80% of dopamine-producing cells have stopped functioning.


The significant decrease in dopamine levels causes the symptoms of Parkinson’s to appear. Fortunately, several drugs are available to compensate for the loss of dopamine, making it possible to control symptoms and preserve an excellent quality of life for several years after a diagnosis has been made. Unfortunately, there are currently no drugs to slow or halt the progression of Parkinson’s.

Progression of parkinson's

Everyone with Parkinson’s is unique and experiences different symptoms. However, since the disease is progressive, existing symptoms will worsen and new ones may appear. 

It’s difficult to estimate how quickly Parkinson’s will progress in a person. In general, the first stage of the disease is a honeymoon period lasting three to eight years, where patients live practically a normal life. It is also the stage where treatment is most effective. 


The disease may progress more quickly in people who are older when symptoms first begin and less quickly when the main symptom is tremor, especially when it starts on one side. You can still lead an active life if you have Parkinson’s, depending on the age you are when symptoms begin, the way you manage your symptoms and your general state of health. 

In most cases, Parkinson’s does not reduce life expectancy. However, risks increase as people age and the disease progresses. For example, balance problems can lead to falls, and swallowing problems can cause pneumonia if left untreated. Parkinson’s is a chronic (long-term) disease that requires constant vigilance and management to preserve quality of life.



There are four main symptoms of Parkinson’s diseas. Parkinson’s disease can be diagnosed when two of the first three symptoms are present. People with Parkinson’s can also exhibit nonmotor symptoms.

Non motors

People with Parkinson’s can also experience other changes, called “nonmotor symptoms,” that can impact their quality of life. Many people do not realize that these symptoms are linked to Parkinson’s.

Related diseases

Essential tremor

In popular beliefs, tremor is often associated with Parkinson’s disease. That is why Parkinson’s disease is often mistaken with essential tremor, which manifests itself solely by a tremor, unlike Parkinson’s disease. The person is not inconvenienced with the slowness and rigidity typical to Parkinson’s disease.

The fundamental difference between those two states resides in the type of tremor. In Parkinson’s disease, tremor manifests itself mostly at rest and fades as the person tries to perform an action. In essential tremor, it is present when executing an action, like holding a cup. Despite this theoretical difference, differentiation between essential tremor and resting tremor associated with Parkinson’s disease in practice may be complex and is sometimes a difficult task.

Parkinsonian syndroms

Parkinsonian syndromes refer to a whole set of diseases presenting symptoms typically associated with Parkinson’s disease, such as slowness, tremor, stiffness and balance disorder, but are accompanied with additional symptoms, designated as “Parkinson Plus”. This is the list of different diseases that may be mistaken with Parkinson’s disease:

  • Progressive supranuclear palsy
  • Multiple system atrophy
  • Striatonigral degeneration
  • Sporadic olivopontocerebellar atrophy
  • Shy-Drager syndrome
  • Corticobasal ganglionic degeneration
  • Dementia with Lewy bodies 

It may be difficult for the neurologist to make a specific diagnosis in the early stages. Differences between Parkinson’s disease and a parkinsonian syndrome are very subtle. Therefore, the presence of symptoms that are not typical to Parkinson’s disease, such as loss of vision, falls in the early stage, important cognitive losses and the discovery of atypical signs at the clinical exam may lead to a parkinsonian syndrome diagnosis.

A parkinsonian syndrome diagnosis is often confirmed after a levodopa treatment because in this case, there is no or very little response to this pharmacological treatment. Parkinsonian syndromes often have a faster progress than Parkinson’s disease and unfortunately, very few therapeutic interventions are able to alleviate the symptoms of the affected person.

For more informations

please consult the parkinson info center