Many people with Parkinson’s experience some mild memory loss and thinking problems. Symptoms vary widely and may fluctuate through the day. Research has shown that cognitive problems tend to be more severe in people with Parkinson’s with more pronounced bradykinesia (slow movement) and rigidity, and less severe in those with more pronounced tremor.

If you are experiencing changes in your thinking and mental abilities, it’s natural to be concerned. You may worry you could go on to develop dementia; however, this happens to comparatively few people. One study found that after ten years with Parkinson’s, 80% of people with the condition experienced some cognitive difficulties, but less than 20% had developed dementia - known as Parkinson’s disease dementia (PDD). The symptoms of PDD are very different from those of Alzheimer’s disease.

Some Parkinson’s symptoms can make speech and facial communication difficult, and slowed thinking will often make things even harder. As the ability to remember words is affected, your vocabulary can become limited and humour may be less understood. It can also get harder to follow conversations, and this can result in you not making sense, or forgetting what you have said and repeating things.

Possible causes

Cognitive problems occur in Parkinson’s, because the areas of the brain involved in memory or thought processes are damaged. As the disease affects these areas, it interrupts signals that pass from one part of the brain to another.

People who have had deep brain stimulation surgery (DBS) may experience particular difficulties with complex thinking, talking and concentrating. But some people report improved memory after such surgery.

Age is one of the strongest risk factors: people under 50 are much less likely to be affected. Other factors that may contribute to cognitive problems include:

• General health and diet – Vitamin deficiencies caused by a poor diet can affect brain function.
• Sleep disturbance and fatigue – Lack of sleep or feeling tired and run-down can affect concentration and memory.
• Anxiety, depression and stress – These can all affect your ability to think clearly, process information, plan and remember.
• Common health problems – Urinary tract infections, abnormal thyroid function and other health problems can cause thinking and memory problems, particularly in older people.
• Other conditions such as diabetes and high blood pressure.

In many cases, a combination of biological and psychological factors may be involved. If you experience any of the problems listed above, it is important to tell your doctor. Treating these factors can not only help to relieve thinking and memory problems, but will also improve your quality of life.

If you are experiencing thinking or memory problems, it is important to talk to your doctor or another healthcare professional. Before diagnosing MCI your doctor will talk with you and your carer or family, discussing any concentration, memory, language and problem-solving skills.

Recognised rating scales are often used to assess memory and cognitive problems. These involve asking carefully chosen questions and assessing the responses according to a points scale. Rating scales are also used to monitor the effects of treatment.

For more subtle or complex difficulties a neuropsychologist – a psychologist with expertise in how to evaluate behaviour and cognitive ability – may make a more detailed assessment. This can be helpful in distinguishing Parkinson’s from illnesses which give rise to more severe difficulties such as Alzheimer’s disease, stroke or dementia with Lewy bodies (DLB). 

If you experience cognitive problems in the very early stages of Parkinson’s, or agitation or delusions, then Parkinson’s may be not the sole cause. In these cases, your doctor may recommend brain scans and blood tests to search for other treatable causes such as thyroid disease or vitamin B12 deficiency.

Cognitive problems in people with Parkinson’s can be difficult to identify and monitor because the condition can affect facial expression and body language and slow down thought processes and responses. This could make cognitive problems appear worse than they really are or, alternatively, reduced facial expression may mask them.

In addition, people may not recognise any problems they have. For these reasons, observations from carers and family can be very helpful in accurately pinpointing problems and assessing their progress. 

Important! 
Cognitive problems can affect your ability to drive, so regular assessments should be carried out to establish if it is still safe for you to drive. 

See also: Driving.

Treating MCI can be complex and should be managed by those experienced in treating both Parkinson’s and cognitive problems. Various professionals in your healthcare team may be involved: your doctor, a Parkinson’s Disease Nurse Specialist (depending on where you live), a neurologist or a psychiatrist. One of their roles may perhaps be to reassure you that your problems are not serious and do not indicate the onset of dementia. Cognitive symptoms such as impaired abstract thinking, problem solving or visuo-spatial alterations (known as dysexecutive syndrome) are not symptoms of dementia.

There are also many organisations and support groups that offer various kinds of help.

Medication

At present, there is no medication licensed specifically to treat mild memory loss and thinking problems. Medicines used to treat Alzheimer’s disease have not so far been shown to be effective for MCI in people with Parkinson’s.

In some cases, adjusting Parkinson’s medications, for example levodopa, can improve symptoms. This could mean, however, that symptoms such as tremor and rigidity are less well controlled. A trial and error approach, balancing out the pros and cons, is often the best way to proceed. Be aware, though, that in many cases adjusting medication may have little or no benefit.

From what is known about medicines and their effects on cognitive problems, the following may be helpful:

• Medications that improve attention and reduce daytime sleepiness may be effective. These generally boost energy and interest levels which can improve your quality of life, but they will not work if the cause is biological (relating to chemicals in the brain).
• Anticholinergic medications may worsen cognitive problems and may be discontinued.
• Hallucinations may be controlled by reducing or withdrawing some anti-parkinsonian medicines. If they continue to be severe your doctor may prescribe so called atypical neuroleptics such as clozapine or quetiapine. Note that while hallucinations are worrying for the carer, often the person experiencing them is not concerned, so if treatment for them worsens other symptoms, they may be best left untreated.

Keeping physically active and mentally stimulated is very important when living with both Parkinson’s and cognitive problems.

Avoiding stress is also important. Anything that puts you under pressure is likely to worsen memory problems, so try to take each day at a steady pace. Allow time for rest and relaxation, and make time to do the things you enjoy. Relaxing effectively can help to improve your concentration, attention span and ability to plan. Complementary therapies such as yoga and Tai Chi, together with exercise such as swimming may help with this.

We can all be forgetful and while this is often frustrating, a good quality of life can still be enjoyed if you make some adaptations.

You could begin by adapting your home and work environments to accommodate your needs. For example, removing clutter will reduce the number of visual distractions and make it easier for you to find your way around. Keeping furniture in the same place and having a regular daily routine may be helpful. At night, you may find it useful to keep a low-level night light on to minimise possible disorientation if you wake.

As time passes, carrying out more complex tasks is likely to become harder. Try writing down the various steps you have to go through in order to complete specific tasks, and follow these steps one by one.

The following tips may also help maintain brain function and improve quality of life:

• Use memory aids around the home such as large-print calendars and newspapers, clocks and alarms. Display easy-to-follow lists on a pinboard or whiteboard.
• Try to maintain a regular routine each day and keep organised, using cues as reminders.
• Put important items such as keys and glasses in the same place each time.
• Use sticky ‘post-it’ notes to remind yourself to turn off lights or lock doors etc.
• Carry a notebook to record important information.
• Keep a diary.
• Do simple arithmetic or crosswords, and play games that require logical thinking with family or friends.
• Keep a clock in each room and tell the time yourself rather than asking someone else.
• Use pill dispensers and timers to manage your medications. A mobile phone alarm can help you remember to take medication and keep appointments.
• Maintain an active social life so that your mind is stimulated and you do not feel isolated.
• Don’t give up activities easily just because you find concentration difficult. Remember the adage ‘use it or lose it’, but accept that you may take longer or need breaks during activities.
• Try to find a hobby or project you can commit to – painting, photography, researching local or family history, for example.
• Label boxes or cupboards clearly.

Living with or caring for someone with both Parkinson’s and cognitive problems can be very challenging. There will be times when they rely heavily on your help and support, and there will be other times when it is better to take a step back and allow them to do things for themselves. This balance will be difficult to judge to begin with, and it is likely to take time and patience to establish new routines and approaches to day-to-day living.

Encouragement, stimulation and helping the person maintain their independence is very important. The suggestions in the ‘How can I help myself?’ section above may be helpful, but remember that rest is also important.

If cognitive problems become more advanced, support and respite will be essential for carers/partners. There are many trained professionals who can provide expert help and advice, as well as organisations such as carer support groups. The person’s doctor or social worker should be able to identify those who can help in your area, or you may find contacts in a telephone directory or online.

As both cognitive difficulties and some Parkinson’s symptoms can make speech and conversation difficult, the following tips may be helpful when communicating with the person with Parkinson’s:

• Speak very clearly and be patient, giving the person plenty of time to understand and respond.
• Keep information simple, repeating if necessary, or break things down into manageable chunks and make one point at a time.
• Try not to ask questions that require complicated answers.
• Make eye contact and use gestures, facial expressions or touch as these can provide additional cues.
• Be aware that too many people taking part in a conversation can make it confusing for them to follow.

Various groups and organisations such as telephone helplines offer emotional support and/or practical help. Even if you have close family and friends, you might want to talk with an outsider, and such organisations can be very helpful. Your doctor or social worker will be able to help you identify such organisations, or you may find contact details on the Internet.

Content last reviewed: February 2020

We would like to thank Dr Annamária Takáts (Semmelweis University, Budapest, Hungary) for her help in reviewing this information.

• Neuropathological Findings in Parkinson's Disease With Mild Cognitive Impairment – research paper

Articles from Parkinson's Life online magazine

• Weight, sleep and depression linked to risk of cognitive problems in Parkinson’s
• Memory loss could be an indication of Parkinson’s