Parkinson's and dementia: what is their relationship?

My father has had Parkinson's for years and has now started to experience forgetfulness and confusion. Can Parkinson's cause dementia?

Yes, Parkinson's disease can progress with dementia – it's called Parkinson's disease dementia, and it's a 'close cousin' of Lewy body dementia (they share the same mechanism in the brain). Not everyone with Parkinson's develops it, but the risk increases with years of the disease.

What is usually different

More than forgetting facts, you might notice slow thinking, difficulty planning and maintaining attention, and significant fluctuations – good hours and confused hours on the same day. Visual hallucinations (seeing people or animals), very agitated dreams 'acted out' during sleep, and falls are common.

Special attention to medication

This is the most important point for families: in this form of dementia, some medications used in other situations (namely certain antipsychotics for confusion or hallucinations) can cause severe reactions. Therefore, any new medication – even over-the-counter – must be approved by the attending doctor or neurologist, and in emergencies or new consultations, always state that Parkinson's with cognitive changes is present.

Day-to-day, the strategies on this website apply, with an emphasis on fall prevention and sleep routine. And regular follow-up by a neurologist makes a real difference in this type of dementia – it's worth keeping it consistent.