What is Parkinson’s disease?

This Sunday, April 11, is World Parkinson’s Day , a day to raise awareness about this degenerative disease and also pay tribute to the British scientist and neurologist, James Parkinson, who discovered Parkinson’s disease in 1817.

To give more visibility to this disease and learn more about it, we interviewed Dr. Elina Boycheva, associate professor at the School of Biomedical and Health and an expert in neuropsychology.


Parkinson’s disease (PD) is the second most common neurodegenerative disease after Alzheimer’s disease . It is characterized by the loss of dopaminergic neurons (those that produce the neurotransmitter dopamine) mainly in the substantia nigra, an area found in the midbrain or midbrain. It is a slowly progressive disorder that affects a person’s movement, balance, and muscle control, but can also cause cognitive deficits.

The fundamental signs necessary to confirm the diagnosis of the disease include tremor at rest, slowness of movement, rigidity, and postural instability. Although the diagnosis is established with the onset of motor symptoms, there are some so-called non-motor prodromal symptoms that can sometimes precede motor symptoms and appear up to 20 years before them.

The most common prodromal symptoms of the disease are constipation, anosmia (loss of smell), depression, excessive daytime sleepiness, and REM sleep behavior disorder. The presence of fatigue and apathy are other clinical characteristics of the disease and contribute greatly to the decrease in the quality of life of the affected people. Fatigue is also a prodromal symptom of the disorder. Finally, psychotic symptoms can also be observed in some patients, such as hallucinations and delusions, which are the result of a hyperdopaminergic state and are usually induced by chronic administration of dopaminergic drugs.


In industrialized countries, the prevalence of Parkinson’s disease in the general population is estimated at around 0.3% and around 1% in people over 60 years of age. In Spain, approximately 150,000 people suffer from Parkinson’s , most of them are older than 65 years, although there is a significant percentage of affected people (15%) who are less than 50 years old at the time of being diagnosed.

In Spain there is the Spanish Parkinson Federation which is a benchmark on Parkinson’s disease and which develops different training and information actions about the disease and about the support resources available to affected people and their families, as well as actions of collaboration and promotion of research in Parkinson’s. In the capital we also have the Madrid Parkinson Association which belongs to the Spanish Parkinson Federation and which offers specialized rehabilitation for affected people, training actions and research promotion, as well as social awareness campaigns about the disease. among others.


As I mentioned previously, people with the disease can also develop cognitive symptoms. Early Parkinson’s disease has been shown to be associated with significant neuropsychological impairment , especially in tasks involving the frontal lobe. Early neuropsychological deficits are a direct consequence of impaired dopamine production, which in turn influences dopamine pathways that project to the frontal lobes. As a consequence, the most frequent cognitive symptoms are alterations in executive functions such as inhibition, verbal fluency, mental flexibility and abstract reasoning.

Patients often also have deficits in visuospatial capacities (how we manage and analyze space) and these are often a predictor of conversion to dementia in affected people. Language deficits can also be seen, often involving executive components such as verbal fluency and organization, although the language skills of people with Parkinson’s are often largely preserved.

Sometimes those affected can also develop memory disorders, for example, they may be less efficient in the use of grouping strategies when learning a list of stimuli or present a greater susceptibility to the effects of interference. However, language and memory deficits are generally associated with the aforementioned executive impairment and frontal circuit abnormalities, which is why they are not usually considered pure cognitive deficits of the disorder as such.


Neuropsychological intervention in Parkinson’s disease is very important given the high prevalence of dementia in those affected and of mild cognitive impairment (MCI), which is considered a transitory state between normal cognitive aging and dementia . It is estimated that up to 31% of people with Parkinson’s disease develop dementia, and it usually appears after the first year of symptoms onset. Therefore, it is necessary to implement early cognitive intervention techniques in order to prevent cognitive deterioration or to prevent its evolution to dementia, once the diagnosis of MCI has been established.

There are different ways of intervening, on the one hand we have cognitive stimulation that seeks to maintain or optimize general cognitive functioning or its components (executive functions, memory, language, etc.) through different activities and exercises, both group and individual. On the other hand, we have neuropsychological rehabilitation that follows a therapeutic approach and whose objective is to improve or compensate for the neurocognitive deficits produced by the disease. Rehabilitation aims to slow down the deterioration, compensate for the deterioration through the acquisition of other skills and improve or restore damaged cognitive functions, therefore, it seeks to reduce the impact of the disease on the daily life of those affected by increasing their autonomy. and facilitating their social adaptation.

The exercises and activities that are usually used can be carried out both in pencil and paper, as well as on a computer, using different platforms for this purpose and adapting the activities to the level of each patient. Looking ahead, it would be advisable to further promote an individualized approach adapted to the needs and cognitive and functional profile of each affected person, especially in those cases in which there is a diagnosis of mild cognitive impairment or dementia. Sometimes patients receive standardized treatment and in group sessions, an important advance in this regard would be the possibility of offering intensive and individualized treatment at an affordable price for users.