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Problems with thinking, reasoning and remembering in people with Parkinson's disease

"I often come up with the answer long after the question was asked"

  • Similar to the slowness of movement typical of people with Parkinson’s disease (PD), you may also find that you are slower in thinking, reasoning and remembering. These cognitive changes can be very frustrating, but are seldom disabling. Only a minority, perhaps 20% of people with PD, have more significant problems of dementia that interfere with quality of life.

  • The most common cognitive changes include slowed ability to think and process information. You may find it difficult to come up with new ways of solving problems and to change from one subject to another. While changes in memory are less frequent, people with PD tend to forget where and when information was obtained but remember the information itself. You may recall information much better if given cues, or multiple choices to select from.

  • You are likely to be worst when you are anxious, tired or hurried. You can make life easier by always allowing yourself plenty of time and avoiding stressful situations. Simplify information and concentrate on what is most relevant. Make full use of prompts, such as diaries, verbal and written reminders and alarms.

  • Hallucinations (usually taking the form of seeing people or animals that are not there) and delusions (believing things that are not true) can be related to PD or to PD medication. A change in dose, or of drug, may be sufficient for them to disappear.

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  • The development of more serious memory and thinking problems leading to dementia can be easily overlooked. Family and carers can wrongly attribute the slow development of unreliability and behavioural changes to intentional behaviour and laziness. Misunderstanding can then lead to resentment and frustration.

  • You should not jump to the conclusion that any problem with your memory or thinking is due to PD. Everybody takes longer to react and to remember things as they get older. Drug treatment (for PD and for other conditions), depression, infections and metabolic upsets are common causes of confusion and are easily treatable. People with PD can develop other conditions, such as stroke and Alzheimer’s disease, in the same way as anyone else.

  • When visual hallucinations and confusion develop within a few months of onset of parkinsonism, the diagnosis may be a condition called dementia with Lewy bodies (DLB), rather than PD. Some authorities think that DLB and PD with dementia are the same condition. Both groups of patients may benefit from the new cholinergic drugs developed for Alzheimer’s disease.

You should seek specialist advice from a doctor or psychologist if you are concerned about your memory and thinking. 

Useful books include:

‘Coping with Memory Problems’, by Linda Clare and Barbara Wilson, published in  1997 by Thames Valley Test Company. ISBN 1 874 261 113.

Useful websites include:

Memory - Helping Yourself

Lewy Body Dementia Association Inc


This site has been established for the dissemination of information. While every effort is made to ensure that information on this site is accurate and current we accept no liability for any omissions or inaccuracies that may have crept in. If in any doubt please contact your doctor for further advice.

Last Modified 13 August 2004
Maintained by Matthew Harris