Parkinson’s disease is caused by a deficiency of the neurotransmitter called dopamine. Characteristic features include stiff joints, shuffling movements and other motor symptoms. However, the disease can also lead to dementia. When it does, this always occurs in the later part of the disease’s progression. The onset of the motor symptoms always occurs at least one year before the symptoms of dementia emerge.
Parkinson’s dementia accounts for 1.2–3 per cent of all cases of dementia. The risk of developing dementia is four to six times higher in people with Parkinson’s disease than in the general population. The risk is affected by the length of time for which the disease has been present, advanced age and the severity of the disease. Dementia appears to be less common in people where shaking is the most prominent symptom than in those who are primarily affected by balance and gait disturbances.
Common symptoms in Parkinson’s dementia are difficulties with concentration, memory disturbances and a lack of energy. Executive capacity is also impaired. This makes it more difficult for the person to plan a task and to focus and shift their attention, something that is needed in order to perform the task. The patient therefore becomes dependent on those around them to manage everyday tasks. Behavioural disturbances and hallucinations can also be part of the overall picture of the disease.
The disturbance to memory in Parkinson’s dementia is less severe than in Alzheimer’s disease. Memorisation is not impaired to the same extent, and by using clues and hints it is often possible to get the patient to “retrieve” and remember an episode. Reminder notes and other memory support strategies are of limited value, however. On the other hand, for the behavioural disturbances and hallucinations that sometimes occur, information about and explanations of the behaviour can alleviate the strain for the patient and family members alike.
There is no curative treatment for Parkinson’s dementia. In certain cases, the drug Exelon® can suppress the symptoms of dementia. Other Alzheimer’s medications, too, probably have a similar affect, although this has not been scientifically documented.
In cases of confusion or various psychotic conditions, it is necessary to exclude – or treat – any infections or diseases that may be contributing to the occurrence of such symptoms. Medications that may cause the symptoms should also be reduced or discontinued, if possible.
Some of the following symptoms may occur with Parkinson’s dementia: Pain, confusion, repetitive behaviour, hallucinations. For more information about various symptoms click here.