What are the causes of Parkinson’s disease?

Parkinson's disease is an age-related neurodegenerative disorder that leads to a gradual decline of your motor functions. The 5 signs of Parkinson's include tremors, stiffness, balance problems, trouble speaking, and small handwriting.
Parkinson's disease is an age-related neurodegenerative disorder that leads to a gradual decline of your motor functions. The 5 signs of Parkinson's include tremors, stiffness, balance problems, trouble speaking, and small handwriting.

Parkinson's disease is an age-related neurodegenerative disorder that leads to a gradual decline of your motor functions. Parkinson’s disease usually occurs after the age of 60. We look at some of the visible signs that are linked to this condition.

Parkinson’s disease is caused by the death of brain cells (also called neurons) in a part of your brain called the substantia nigra. These brain cells produce a chemical called dopamine, which plays a critical role in several brain functions.

Dopamine is the chemical messenger between the brain and the central nervous system that regulates body movements. When dopamine levels fall below what the brain requires, this leads to unusual brain activity, which leads to the onset of the symptoms linked to Parkinson’s disease.

Although the exact cause of the neuron death that leads to Parkinson’s disease is yet to be determined, many factors are linked to the onset of this condition.

Genetics

Studies suggest that roughly 10% to 15% of all incidences of Parkinson’s disease are linked to genetic factors. Researchers have studied genetic mutations in many cases linked to this condition that have led them to this conclusion.

Parkinson’s disease can run in families, with the genes being passed from parents to their children.

Environmental factors

Although the link between environmental factors and the onset of Parkinson’s disease is still not clear, there is increasing evidence that it may exist. Some environmental factors may increase the risk of Parkinson’s disease considerably, but others may decrease it.

Scientists are constantly working toward understanding these causes. Some people’s genetic makeup could make them more vulnerable to environmental factors like toxins and cause Parkinson’s disease.

Some of the environmental factors that could increase the risk are listed below. More research needs to be done to determine the specific impact of these factors.

Head injuries

Trauma to the head could increase the risk of Parkinson’s disease. If you take part in certain activities that lead to repeated head trauma, you could be more susceptible to this condition even years after the trauma has occurred.

Toxic metals

Many people come in contact with toxic metals at their jobs, and this could be linked to Parkinson’s disease. Long-term effects cannot be measured accurately, so no single incident of contact can be pinpointed as a cause.

Solvents & chemicals

Certain solvents, such as trichloroethylene (TCE), and chemicals, such as polychlorinated biphenyls (PCBs), that are used in some industries may be related to Parkinson's disease. These are also common pollutants found in groundwater.

Some research has linked TCE to Parkinson’s disease in factory workers who came in contact with the chemical over a long time. Other research has established a link between people who were diagnosed with Parkinson’s disease and high levels of PCBs in the brain.

Other factors

Researchers have found certain molecules in the brains of people with Parkinson’s disease. These are called Lewy bodies, and their presence has been linked to the development of the disease.

Lewy bodies are made up of several chemicals, but much of the current research focuses on a particular chemical called alpha-synuclein.

Signs of Parkinson’s disease

It can be hard to know whether you or a loved one has Parkinson’s disease. Keep in mind that just one of these signs is not a cause for concern. But if you think you have most of these signs, check with your doctor.

Tremors

Involuntary shaking of your fingers, hands, or chin can be an early sign of Parkinson’s disease. 

But know that there are situations where some shaking might occur, like after an intense workout or when you’re stressed. It can also be due to a medication that you’re taking. None of these reasons is a cause for concern.

Stiffness or slow, limited range of movement

Has your range of motion decreased in comparison to what it was before? Have people around you noticed that your arms don’t swing as much when you walk?  If so, this could be a sign of Parkinson’s disease. You may also feel that your feet are “stuck to the ground.”

In some cases, you may have what is called “facial masking,” where your face has a serious or depressed look even when you’re feeling fine. Your movements may also slow down, and you may notice that your steps are smaller than they used to be.

If you’re injured or have stiffness in parts of your body due to, for example, sleeping in an unusual position, this may restrict your movements. This is OK, and you’ll retain full movement over time.

Loss of balance and posture

If your family has noticed that you’ve started slouching or stooping, or if you’re doing it more than you usually do, it could be a cause for concern. 

If an existing injury or any other condition is causing pain and is the reason you’re unable to stand straight, then you don't need to worry.

Trouble with speaking

If you constantly hear people telling you that your voice is not audible or that it’s very soft, you should have it checked by your doctor. In some cases, you may think that the other person is unable to hear properly, when it’s actually that your voice isn't loud enough. 

Know that conditions such as chest infections and common colds can make your voice sound different, but with those, you’ll get your voice back over time.

Small handwriting

Have you noticed that your handwriting has become smaller than it was before? If your letters are smaller and the words seem more crowded together, it could be a sign of Parkinson’s disease. 

But note that handwriting usually becomes smaller as a person grows older.

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What can you do if you think you have Parkinson’s disease?

If you think you have signs of Parkinson’s disease, ask your doctor for a referral to a neurologist who specializes in brain care. Talk to your family members who can provide support and help you make the right decisions.

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Medically Reviewed on 7/18/2022
References
SOURCES:

National Health Service: "Parkinson's disease."

National Institute of Aging: "Parkinson's Disease: Causes, Symptoms, and Treatments."

Parkinson’s Foundation: "10 Early Signs of Parkinson's Disease," "Causes," "Environmental Factors."