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What is Parkinson's disease?

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Parkinson's disease is an incurable, progressive, neurodegenerative disorder with a gradual onset and chronic nature. It is characterised primarily by motor disorders such as slowness of movement, rigidity, tremor and gait abnormalities. It is also associated with a wide range of non-motor disorders.

In many global epidemiological registries, Parkinson's disease is the neurodegenerative disease with the fastest-growing incidence.

It is mostly a sporadic disease, but 5-10% of cases can be hereditary. Genetic forms are common in certain geographic areas and ethnicities.

There are numerous effective symptomatic treatments, both pharmacological via different routes of administration (oral, transdermal, subcutaneous and inhaled) and surgical (deep brain stimulation), which substantially improve quality of life. Currently, there is intense research on the cause, biomarkers and treatments that modify the course of the disease.

Parkinson’s disease

There are many ongoing lines of research that are exploring both the cause of the disease and treatments that can modify the course of the disease. There are many treatments available that will allow you to lead a quality life for many years.

Almudena Sánchez Neurologist

Parkinson's disease explained in fi...

Research keeps going forward. There are surgical interventions that can improve our quality of life a lot.

Artur Patient

Neurochemical alteration in Parkinson’s disease

The common denominator is neuronal degeneration, initially in the brainstem, including the substantia nigra of the midbrain. This leads to a dopamine deficit, which explains the motor symptoms and some of the non-motor symptoms of the disease. As the disease progresses, many other types of neurons are diffusely affected throughout the brain. Affected neurons contain Lewy bodies, which are protein aggregates composed primarily of alpha-synuclein. Because of this, Parkinson’s disease is classified as a synucleinopathy.

Types of Parkinson’s disease

Despite this common chemical and anatomical alteration, there are different types of Parkinson’s disease. Several ways to classify it are:

According to motor symptoms: tremor-dominant Parkinson’s and rigid-akinetic-dominant Parkinson’s. The former has a better prognosis.
According to age of onset: juvenile-onset Parkinson’s (<20 years, very unusual), young-onset (<50 years, not infrequent), and adult-onset (>50 years with an average age of 65, the most common).
According to family history: sporadic form and familial form.
According to genetics: monogenic Parkinson’s (which may be familial or apparently sporadic with low-penetrance mutations) and polygenic (multiple genetic variants that separately pose low risk, but in combination may explain the disease).
According to non-motor symptoms: there are cases with non-motor predominance (with sleep disorders, dysautonomia, psychiatric, cognitive dysfunction, etc.), with very mild motor symptoms.
According to cognitive involvement: Parkinson’s without cognitive impairment, Parkinson’s with mild cognitive impairment, and the spectrum of Parkinson’s with dementia or dementia with Lewy bodies. Some epidemiological studies have spoken of the “inevitability” of dementia in Parkinson’s, but up to 20% or more of patients after 10 or even 20 years of progression still show appreciable cognitive preservation.
According to the topography of onset and progression: we speak of the “body-first” variants in which molecular alterations begin in the peripheral nervous system with autonomic involvement (constipation, hypotension) and sleep (REM sleep disorder) followed by a more aggressive central disease, and “brain-first” in which asymmetric tremor predominates and the disease is more benign.

There is extensive research into the biological and environmental factors that may explain this significant clinical heterogeneity among patients.

How many people are affected?

An incidence of between 8 and 19 new cases per 100,000 people per year has been reported in the general population. It is rare in people younger than 40 years and increases with age. At 65 years it would be approximately 50 per 100,000, and at 85 years about 400 per 100,000. It is estimated that the incidence will double in the coming decades. The prevalence (persons affected at a determined time, whether new or previously) increases with age, and it is estimated to be around 0.5% at 65 years, and between 1% - 4% between 70-85 years. It affects between 100 and 200 cases for every 100,000 persons. It is slightly more frequent in males than in females (ratio 3:2, approximately).

Substantiated information by:

Almudena Sánchez Gómez

Ana Cámara Lorenzo

Maria José Martí Head of the Parkinson's and Movement Disorders Unit

Yaroslau Compta Hirnyj Neurologist Neurology Service

Published: 8 July 2019
Updated: 30 July 2025

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