Parkinson’s disease: symptoms, prevention, and treatments

Parkinson’s disease is a degenerative disease that results from the slow and progressive death of neurons in the brain. As the area of the brain affected by the disease plays an important role in controlling our movements, sufferers gradually make rigid, jerky, and uncontrollable gestures.

Find out everything you need to know about this disease in this fact article.

What is Parkinson’s disease?

Parkinson’s disease is a disease of the nervous system that affects movement. It develops gradually, sometimes starting with a barely noticeable tremor with one hand. It also causes stiffness or slowing of movement.

Parkinson’s disease is a degenerative disease that results from the slow and progressive death of neurons in the brain. As the area of the brain affected by the disease plays an important role in controlling our movements, sufferers gradually make rigid, jerky, and uncontrollable gestures.

For example, bringing a cup to your lips with precision and flexibility becomes difficult. Nowadays, available treatments can reduce symptoms and slow the progression of the disease quite effectively. You can live with Parkinson’s for several years.

Parkinson’s-related disorders most often appear around the age of 50 to 70. The average age of onset of illness in Canada and France is 57 years. At first, the symptoms may be confused with the person’s normal aging but as they worsen, the diagnosis becomes more obvious. By the time the first symptoms appear, it is estimated that 60% to 80% of the nerve cells in the substantia nigra (see box) are already destroyed. Thus, when symptoms appear, the disease already has an average of 5 to 10 years of evolution.

Globally, the disease is diagnosed in more than 300,000 people each year. The number of cases increases with age. It is estimated that at age 65, one in 100 people would be affected, and 2 in 100 people would be affected by age 70 and over.

At the heart of the disease: a dopamine imbalance

The nerve cells affected by Parkinson’s disease are located in an area called “substantia nigra” and located in the midbrain, in the center of the brain. The cells in this area produce dopamine, a chemical messenger (called a neurotransmitter) that allows the control of movement but also acts in the sensation of pleasure and desire.

The death of substantia nigra cells creates a lack of dopamine, resulting in an increase in acetylcholine and glutamate (two other chemical messengers). This imbalance provokes the appearance of the symptoms of the disease, namely tremors, muscle rigidity, and an inability to perform certain movements.

Conversely, an excess of dopamine could cause symptoms associated with schizophrenia.

Parkinson’s disease: the causes

What causes the progressive loss of neurons in Parkinson’s disease remains unknown in most cases. Scientists agree that a set of genetic and environmental factors are involved, without always being able to define them clearly.

According to the current consensus, the environment would play a more important role than heredity but genetic factors would be predominant when the disease appears before the age of 50. Some of the environmental factors involved include:

  • early or prolonged exposure to chemical pollutants or pesticides, including herbicides and insecticides (for example, rotenone) ;
  • MPTP, a drug that sometimes contaminates heroin, can suddenly cause a severe and irreversible form of Parkinson’s. This drug exerts its effect in a similar way to the pesticide rotenone;
  • carbon monoxide or manganese poisoning.

The researchers also noted that many changes occur in the brains of people with Parkinson’s disease, although the reasons for these changes are not established. These changes include:

The presence of Lewy’s bodies

These are substances found in brain cells (neurons). Researchers believe that these Lewy bodies play a toxic role in Parkinson’s disease.

The presence of alpha-synuclein in Lewy bodies

Although many substances are present in Lewy bodies, scientists believe that alpha-synuclein is a protein that plays a harmful role when in an aggregated form that cannot be dissolved by cells.

Parkinson’s disease: evolution and possible complications

The progression of Parkinson’s disease varies from individual to individual. Parkinson’s disease is chronic and progresses slowly, which means that symptoms worsen over several years:

  • motor symptoms vary from person to person, as well as their progression;
  • Some of these symptoms are more troublesome than others depending on what a person normally does during the day;
  • some people with Parkinson’s disease live with less disabling symptoms for many years, while others develop motor difficulties more quickly;
  • Non-motor symptoms also vary from individual to individual and affect most people with Parkinson’s disease, regardless of the stage of the disease. Some people with the condition find that symptoms such as depression or fatigue interfere more with their daily activities than motor problems.

Parkinson’s disease is often accompanied by the following problems that can be treated.

Thought difficulties

The onset of cognitive impairment usually occurs in the later stages of the disease. Such cognitive problems do not respond very well to medication.

Mood disorders

People with Parkinson’s disease may suffer from depression. By receiving treatment for depression, it is easier to manage the other problems of Parkinson’s disease. Other disorders such as anxiety or loss of motivation may accompany depression.

Swallowing problems

The person has difficulty swallowing as their condition worsens. Saliva can accumulate in the mouth due to slow swallowing.

Sleep disorders

People with Parkinson’s disease often have sleep problems. They frequently wake up at night, wake up early or fall asleep during the day.


Parkinson’s disease can cause bladder problems, resulting in an inability to control urine or difficulty urinating.


Many people with the condition become constipated, mainly due to a slower digestive tract.

Change in blood pressure

This change may be accompanied by dizziness or dizziness (orthostatic hypotension).

Smell disorders

Difficulty identifying or differentiating certain odors.


Many patients experience fatigue, and the cause is not always known.


Many people with the condition suffer from pain, either in specific areas of the body or throughout the body.

Sexual dysfunction

Some people with the disease report a decrease in sexual desire or performance.

Symptoms related to motor skills often appear asymmetrically, that is, by reaching only one side of the body.

Find out more details and the full list of symptoms of this disease below.

Parkinson’s disease: the symptoms

Motor symptoms often appear asymmetrically, that is, reaching only one side of the body, and then spreading to both sides of the body after a few years.

Most common symptoms

In 70% of cases, the first symptom consists of uncontrollable rhythmic tremors of one hand, then of the head and legs, especially at rest or during times of stress. On the other hand, 25% of patients have no tremors.

The tremor that occurs during the action, for example, when lifting an object, is not a sign of Parkinson’s.

  • A decrease and cessation of tremors when the person makes movements and sleep;
  • stiffness of the limbs, slow movements (bradykinesia), rigid and jerky, and difficult to initiate. As the disease progresses, it can cause difficulty performing daily tasks such as buttoning clothes, tying shoelaces, picking up coins, walking, getting out of a car;
  • The Parkinsonian gait is characteristic: small steps dragging the feet, the back hunched, with little or no swinging of the arms;
  • loss of olfaction, sleep disorders, and constipation, which may appear early;
  • loss of balance, occurring later in the course of the disease.

Other symptoms, as appropriate

  • Depression and anxiety;
  • difficulty swallowing
  • excessive salivation with difficulty containing saliva (the person drools);
  • a small, very tight handwriting (micrograph), due to the loss of dexterity;
  • a chirping, expressionless voice and difficulty articulating;
  • an absence of facial expression, with a decrease or absence of eyelid flutter;
  • the presence of dandruff and oily skin on the face;
  • urinary incontinence
  • confusion, memory loss, and other fairly significant mental disorders occurring rather late in the course of the disease;
  • difficult changes of position; It can be difficult to get out of bed or chair, for example. And in some cases, it becomes impossible to move.

Parkinson’s syndrome or Parkinson’s disease?

Symptoms similar to Parkinson’s disease may appear in some, but the diagnosis of Parkinson’s can not be made. In fact, Parkinson’s disease accounts for 85% of cases of a set of diseases called “parkinsonism syndrome”. The latter is also manifested by movement disorders but the physiology of the disease differs.

Indeed, parkinsonism is usually caused by an imbalance in the cholinergic system (acetylcholine) rather than a dopamine deficiency. Overall, some differences are visible and the treatment is not the same.

Conditions that can trigger parkinsonism include damage to the brain as a result of trauma or tumors, small strokes, and the use of certain medications used to treat nausea, epilepsy, hypertension, or psychiatric disorders.

Various infrequent neurological diseases also manifest as parkinsonism.

Parkinson’s disease: how to diagnose it?

There is no specific test to diagnose Parkinson’s disease. The neurologist will diagnose the disease based on the person’s medical history, a review of signs and symptoms, and a neurological exam.

The doctor may ask for tests, such as blood tests, to rule out other conditions that may be causing these symptoms.

Imaging tests, such as an MRI or brain scan, can also be used to help rule out other disorders. Imaging tests are not particularly useful for diagnosing Parkinson’s disease.

In addition to a standard exam, your doctor may give the person carbidopa-levodopa, a medicine used to treat Parkinson’s disease. She must receive a sufficient dose for a benefit to be observed, as low doses given for a day or two are not sufficient. Significant improvement with this drug will often confirm a diagnosis of Parkinson’s disease.

Diagnosing Parkinson’s disease can take time. Doctors may recommend regular follow-ups to assess the person’s condition and symptoms over time and diagnose Parkinson’s disease.

Some people are at higher risk of developing Parkinson’s disease. Also, risk factors favor its appearance.

Discover them here.

Parkinson’s disease: people at risk

  • The disease more often affects people aged 55 and over;
  • men are more often affected than women for unknown reasons;
  • A person with a parent with the disease has a higher risk of developing the disease themselves. But the genetic contribution would be especially important in those who develop the disease when they are young.

Parkinson’s disease: risk factors

People with Parkinson’s disease often experience periods of depression. However, researchers are now studying the hypothesis that depression is a predisposing factor to the disease.

However, this remains to be demonstrated. It may be that, in some, it is only an early manifestation of the disease.

There is no doctor-recognized way to prevent Parkinson’s disease.

However, find out below what the research indicates.

Parkinson’s disease: preventive measures


Men who consume caffeine drinks (coffee, tea, cola) moderately (1 to 4 cups per day) may have a protective effect against Parkinson’s disease, according to large cohort studies. A study of a population of Chinese origin showed the same effect.

On the other hand, in women, the protective effect has not been demonstrated as clearly. Still, an 18-year cohort study found that the risk of Parkinson’s disease decreased in coffee drinkers who did not take hormone replacement at menopause. Conversely, taking hormone replacement and caffeine combined would increase the risks.

Green tea

Drinking one to four cups of green tea a day also seems to prevent Parkinson’s disease, an effect that is thought to be due, at least in part, to the presence of caffeine in green tea. In men, the most effective doses range from about 400 mg to about 2.5 g of caffeine per day, or a minimum of 5 cups of green tea per day.


In addition, people dependent on tobacco would be less at risk of having Parkinson’s disease. According to a meta-analysis, this risk would be reduced by 56% in smokers, compared to those who have never smoked.

Nicotine stimulates the release of dopamine, thus compensating for the dopamine deficiency found in patients. However, this benefit does not weigh heavily compared to all the diseases that can cause by smoking, including several types of cancer.


Several meta-analyses indicate that ibuprofen may be associated with a reduced risk of Parkinson’s disease. Data for other nonsteroidal anti-inflammatory drugs (NSAIDs) are conflicting, with some meta-analyses finding that NSAIDs are associated with a reduced risk of disease while others report no significant association.

While there are no treatments that can cure Parkinson’s disease, it is nevertheless possible to reduce its symptoms by the use of medication but also by following certain lifestyle measures. Generally, symptoms are controlled with sufficient success if treatment is well-adjusted according to the course of the disease.

Despite the anxiety and discouragement that the disease can cause, having an active role in its management allows you to live better with the decisions that have been made.

More information on possible medical treatments is below.

Parkinson’s disease: how to treat it?


Stay active

It is very important that the patient remains active and exercises. Regular physical activity increases mobility, balance, and coordination of the body and helps fight depression. The doctor may suggest a particular exercise program but any form of physical activity (walking, swimming, gardening, etc.) is beneficial.

In addition, as people with Parkinson’s disease are more prone to osteoporosis, it is advisable to practice weight-bearing joint exercises to strengthen the skeleton (lifting weights, walking, jogging, jumping on the spot, etc.). Always in the same vein, it is also necessary to take a small regular “dose” of the sun to counter a possible lack of vitamin D, a common deficiency in the case of Parkinson’s disease. Vitamin D plays a vital role in bone health.

Give yourself periods of relaxation

Practicing a relaxation technique, such as yoga or tai chi, or using massage therapy is important to reduce stress (see Other approaches). In people with Parkinson’s disease, stress has the effect of increasing the intensity of tremors.

Preventing falls

The more the disease progresses, the more difficult walking becomes. It is then important to get good shoes – avoid slippery soles – and to practice making long strides by lifting your legs high. Walking training by a physiotherapist is often recommended.

In order to minimize the risk of falls, the patient’s space should be arranged appropriately. For example, it is better to remove rugs and install grab bars near toilets and bathtubs and handrails on stairs. An occupational therapy assessment is often necessary.


In order to increase the beneficial action of levodopa (see below), the doctor may make certain dietary recommendations. Consuming the majority of protein at the evening meal and maintaining a carbohydrate/protein ratio of 7:1 (7 g of carbohydrates to 1 g of protein), for example, is a favorable measure. According to the Parkinson Society in Quebec (see Sites of Interest), the vegetarian diet naturally offers such a carbohydrate/protein balance.

Consult the Vegetarianism sheet.

At the Mayo Clinic, it is recommended to have a diet rich in fruits, vegetables, and whole grains, which provide natural antioxidants that protect against oxidative damage. These foods are also a good source of dietary fiber, which promotes better intestinal transit. Consumption of saturated fats (red meats, dairy products, palm, and coconut oil, etc.) should be reduced.

At an advanced stage of the disease, chewing becomes difficult: it is important to take small bites. To facilitate swallowing, more substantial foods can be blended before eating.

In order to prevent constipation related to Parkinson’s disease, doctors recommend drinking at least 1 liter of water a day and consuming enough dietary fiber.

Social support

The use of a resource person (a psychologist, a psychotherapist, etc.) is often useful, even necessary, to cope with the ordeal of any chronic disease. Parkinson’s disease can be particularly difficult to cope with since it attacks the biochemistry of the brain, which is often a major source of anxiety. You can also join a support group.


The appropriate time to start medication depends on several factors (age, lifestyle, severity of symptoms, hobbies, etc.) and will be determined in consultation with the doctor. Prescribed medications are intended to reduce the symptoms of the disease, but do not stop its progression.

Finding the ideal treatment can take time; It is recommended to report any new symptoms that appear during treatment to your doctor to make the necessary adjustments.

Levodopa or L-dopa, is a precursor of dopamine

In the brain, levodopa is converted into dopamine. It is often prescribed in conjunction with carbidopa or benserazide to increase the effects or limit the side effects (nausea, vomiting, dizziness upon waking).

Levodopa is particularly effective in alleviating movement difficulties, tremors, and rigidity of the limbs. As the effectiveness of levodopa decreases over time – it often becomes much less effective after 5 or 6 years – doctors usually wait until the symptoms of the disease are significant before prescribing it.

Dopamine agonists mimic the effects of dopamine (bromocriptine, pergolide, pramipexole, and ropinirole are examples). These drugs can be prescribed as soon as the diagnosis is made and be combined with levodopa when the disease is at an advanced stage.

These drugs have side effects similar to levodopa, but they can also cause compulsive behaviors (compulsive gambling, hypersexuality, compulsive shopping), in 7 to 13% of cases according to some studies36.

Monoamine oxidase B inhibitors (MAOI B)

Monoamine oxidase B (MAOI B) inhibitors, such as selegiline and rasagiline, may be prescribed early in the disease. They decrease the breakdown of natural dopamine that is formed from levodopa. In addition, they would prevent the formation of free radicals and neurological toxins, thus protecting healthy cells.

This protective effect is not fully demonstrated. This class of drugs sometimes causes side effects, such as tremors and confusion. It has many interactions with other medications and natural health products.


Anticholinergics (benztropine, trihexyphenidyl) help reduce tremors in some people by restoring the balance between dopamine and acetylcholine in the brain. It is usually prescribed to younger patients in whom tremors are the dominant symptom. This is the oldest type of medication that is offered to patients.

Catechol O-methyltransferase (COMT) inhibitors

They prolong the effect of carbidopa-levodopa treatment by blocking the enzyme that degrades levodopa. Tolcapone is only prescribed to people who do not respond to other therapies because it can lead to liver damage.

Entacapone (Comtan) does not cause this problem. It is combined with carbidopa and levodopa in the Stalevo®. However, it can worsen the side effects of levodopa.


This antiviral drug, originally developed to treat influenza, has shown beneficial effects for people with Parkinson’s disease. Because this medication only slightly reduces symptoms, it is used in patients who are at an early stage of the disease. Its mechanism of action in the brain is not yet well known. When combined with levodopa, amantadine may help reduce motor problems in the advanced stages of the disease.

Note: levodopa and dopamine agonists may cause daytime drowsiness. Vigilance is required since some patients treated with these drugs may suffer from drowsiness during full activity (for example, driving a car).

In addition to medications to reduce motor disorders, an antidepressant is sometimes prescribed. Several factors can lead to a depressive state in the patient: having to live with a chronic degenerative disease, the usual tasks that gradually become more difficult, the physiological changes that take place in the brain during the disease, and the side effects of certain medications.


For patients with advanced disease, whose symptoms no longer respond stably to levodopa, brain surgery may be considered.

Deep brain stimulation involves implanting electrodes in specific parts of the brain (the thalamus, pallidum, or subthalamus). A stimulator then sends electrical impulses to reduce involuntary movements and tremors. However, this procedure does not decrease muscle rigidity, does not correct the loss of voluntary movement, and would carry some risks of serious side effects.

Previously, small lesions were made in the portion of the brain responsible for Parkinson’s symptoms: pallidotomy (pallidum), thalamotomy (thalamus), or sub-thalamotomy (subthalamic nucleus). These very delicate brain surgeries are now very rarely used.

Physiotherapy and speech therapy

Physiotherapy which includes daily physical exercise, gymnastics, walking training, postural balance work, etc. is an important therapeutic complement. Occupational therapy is indicated for functional rehabilitation and home adaptation. Speech therapy allows the management of dysarthria, a language expression disorder due to difficult articulation.

Experimental treatments

Various innovative treatments, such as fetal dopamine cell transplantation and gene therapy, are being studied, but these are experimental treatments, none of which are commonly practiced.

In the case of Parkinson’s disease, some complementary approaches make it possible to treat it in a more natural way.

Check out the list here.

Parkinson’s disease: complementary approaches

In prevention

Vitamin E (food source only)

Eating foods rich in vitamin E could prevent Parkinson’s disease. Researchers are interested in the effects of antioxidant consumption since oxidation mechanisms could be involved in the onset of the disease. By observing the diets of 76,890 women (aged 30 to 55) and 47,331 men (aged 40 to 75) over a 14-year period, the researchers came to this conclusion.

Specifically, antioxidant vitamin intakes from diet or supplements were analyzed. Only patients whose diets included important sources of vitamin E (nuts, seeds, green leafy vegetables) were less prone to the disease. Vitamin E supplements did not have this protective effect.

In treatment

Music therapy

There is some evidence that music therapy, used alone or with physiotherapy, may help increase motor coordination in people with Parkinson’s disease. Improvements were observed in walking speed, step distance and cadence, generalized slowness, and accuracy of movement.

In addition, some benefits in terms of emotional functions, language, and quality of life have also been documented. Most studies were conducted with small samples and had methodological shortcomings. More research will be needed to confirm these findings.

Coenzyme Q10 (ubiquinone 50)

Two studies evaluated the effect of coenzyme Q10 on disease progression.10,20 One of them gave positive results with a dose of 1,200 mg per day.

One of these studies, involving doses of 300 mg per day given as intravenous nanoparticles, had no significant effects. Further clinical trials are therefore needed before recommending its use.

Coenzyme Q10 is necessary for the proper functioning of cells and energy production. Its level in serum would decrease with age, and even more so in people with a chronic disease (including Parkinson’s disease).

Traditional Chinese Medicine

Acupuncture has long been used in China to treat Parkinson’s disease. Electroacupuncture could lead, in the long term, to the regeneration of neurons affected by the disease.

A clinical study involving 29 subjects with Parkinson’s disease indicated that acupuncture could reduce the symptoms of the disease, slow its progression and reduce the dosage of medications.8 Some have observed a beneficial effect only for rest, with acupuncture improving sleep.

The combination of acupuncture and Tui Na massage may reduce tremor symptoms (depending on the stage of the disease) and reduce medication in some. The Parkinson Recovery Project (see Sites of Interest) has developed a treatment protocol using mainly Tui Na massage.

Technique Alexander

This mode of postural or psychomotor rehabilitation advocates the development of attention and movement control. Practitioners of this technique consider it a good therapy for people with Parkinson’s.

In addition, a study confirms that this technique is likely to help people with Parkinson’s disease in a lasting way, by improving both physical abilities and mood.


This mind-body approach aims to free the body and mind through touch and movement education. Trager has demonstrated favorable results as a complementary therapy in gerontology and for people with neurological disorders, including Parkinson’s disease.

Yoga and relaxation

An approach like hatha-yoga (yoga of the body) is particularly interesting because it emphasizes balance and flexibility of the body in addition to giving a lot of space for relaxation. It is essential that the patient learns to relax since stress systematically increases the intensity of tremors

Taï chi

Tai Chi is a martial art of Chinese origin that uses slow, fluid movements to improve flexibility, balance, and muscle strength. Tai chi can also prevent falls. Several forms of tai chi are suitable for people of all ages and physical conditions.

One study found that tai chi can improve balance in people with mild to moderate Parkinson’s disease.

Image Credit: Image by storyset on Freepik

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