Parkinson’s dementia arises from Parkinson’s disease . It appears in 20-60% of the cases in which this condition occurs, and involves a series of motor symptoms (tremors, slowness…), impoverishment in language and thought and cognitive symptoms.

This is a subcortical dementia that usually appears in advanced ages. Although the cause is unknown, a significant decrease in the amounts of dopamine in the brain has been observed in patients with Parkinson’s dementia. Let’s see what its characteristics are.

Parkinson’s Dementia: Characteristics

Parkinson’s dementia arises from Parkinson’s disease. Specifically, between 20 and 60% of people with Parkinson’s disease eventually develop Parkinson’s dementia as well.

As for its course, it starts between 50 and 60 years old . The deterioration is usually slow and progressive, and affects the cognitive, motor and autonomy skills of the person. On the other hand, its incidence is about 789 persons per 100,000 (over 79 years old).

Parkinson’s Disease

Parkinson’s disease causes certain motor disorders, such as tremor at rest, slowness of movement, postural instability , difficulty in starting and stopping an activity, stiffness and festination gait (shuffling and short steps).

But, in this article we will focus on dementia arising from the disease:


When the disease progresses into dementia, it is characterized by a series of symptoms. According to the Diagnostic Manual of Mental Disorders (DSM-IV-TR), a dysjunctional syndrome linked to memory loss usually appears. In addition, other symptoms that appear are:

1. Decreased motivation

This translates into apathy, asthenia and abulia . That is, the person loses the desire to do things, the pleasure that was previously experienced with them disappears, there is no motivation or will, etc.

2. Bradypsyche

Another typical symptom of Parkinson’s dementia is bradypsychia, which involves a slowing down of the thinking process . In addition, an impoverishment of language is also associated with it.

3. Bradykinesia

It implies slow movements , something that has to do with both the Central Nervous System and the Peripheral Nervous System.

4. Visuospatial and visoconstructive alterations

There is also an effect on the visuospatial and visoconstructive areas, which translates into difficulties in moving and positioning oneself in space, drawing, locating objects in space, etc., as well as difficulties in building (for example, a tower with cubes) and dressing.

5. Depression

Parkinson’s dementia is also very often accompanied by more or less severe depressive disorders .

6. Neuropsychological disorders

Disturbances in memory and recognition appear, although these are less severe than in the case of Alzheimer’s dementia, for example.

With regard to coding and information recovery, there are major flaws in the processes of memory recovery .


The causes of Parkinson’s disease (and therefore of Parkinson’s dementia), are actually unknown. However, has been linked to alterations in the nigrostriatal fascicle , specifically a decrease in dopaminergic functioning in that structure. Dopamine is a neurotransmitter that is closely related to movement and movement-related disorders characteristic of Parkinson’s dementia.

In addition, it has been observed that in patients with Parkinson’s Lewy bodies appear in the substantia nigra of the brain and in other nuclei of the brain stem. It is not known, however, whether this is a cause or a consequence of the disease itself.

Population at risk

The population at risk for Parkinson’s dementia, i.e. people most vulnerable to developing it, are older people, who have had a late onset of Parkinson’s disease , with greater severity in the disease itself, and with predominant symptoms of rigidity and akinesia (inability to initiate precise movement).


Today, Parkinson’s dementia is a degenerative disease with no cure. Treatment will be based on trying to delay the appearance of the symptoms and on treating or compensating for those that already exist, so that they affect them as little as possible.

For this purpose , cognitive neurorehabilitation program will be used, as well as external strategies that can help the patient in his environment (use of agendas and reminders for memory, for example).

In addition, the symptoms associated with dementia, such as those of depression or anxiety, will be treated on a psychological and psychopharmacological level.


On a pharmacological level and to treat the motor symptoms of the disease (not so much dementia), antiparkinsonian drugs are usually used . These are aimed at restoring the balance between the dopaminergic system (dopamine), which is deficient, and the cholinergic system (acetylcholine), which is over-excited.

Levodopa is the most effective and most widely used drug. Dopamine agonists are also used, which increase their effectiveness in combination with levodopa (except in the very early stages of the disease, where they can be given in isolation).

Parkinson’s as Subcortical Dementia

As we have mentioned, Parkinson’s dementia consists of subcortical dementia ; this means that alterations are produced in the subcortical area of the brain. Another large group of dementias is cortical dementia, which typically includes another well-known dementia, that due to Alzheimer’s disease.

But, continuing with subcortical dementias, these include in addition to Parkinson’s dementia (dopamine deficit), Huntington’s dementia (involving GABA deficits) and HIV dementia (involving alterations in the white matter).

All subcortical dementias have as characteristic symptoms motor disorders (extrapyramidal symptoms), slowing, bradypsychia and decreased motivation.

Bibliographic references:

  • Belloch, A., Sandín, B. and Ramos, F. (2010). Manual of Psychopathology. Volume I and II. Madrid: McGraw-Hill.
  • Demey, I. and Allegri, R. (2008). Dementia in Parkinson’s disease and dementia with Lewy bodies. Revista Neurológica Argentina, 33: 3 – 21.
  • Rodríguez-Constenla, I., Cabo-López, I., Bellas-Lama, P. and Cebrián, E. (2010). Cognitive and neuropsychiatric disorders in Parkinson’s disease. Rev Neurology, 50(2): S33 – S39