Q&A: Dementia and Parkinson's

Dr Zuzana Walker joined our discussion forum in August 2012 for a question and answer (Q&A) session on Parkinson's-related dementia.

What is dementia?

Dementia is a term used to describe a set of symptoms that are caused by a significant loss in brain function.

These symptoms may include memory problems, slow thought processes, difficulty concentrating, a lack of motivation or interest and hallucinations, among others.

There are 2 types of dementia related to Parkinson's. These are:

• Parkinson's dementia
• Dementia with Lewy bodies

When the motor symptoms of Parkinson's are present for at least a year before experiencing dementia, this is known as Parkinson's dementia.

Dementia with Lewy bodies is diagnosed when the symptoms of dementia appear before or at the same time as Parkinson's symptoms.

The symptoms present in dementia can vary from person to person and according to the type of dementia a person might have.

Transcript of the session

Julia: Does Parkinson's-related dementia differ from other forms of dementia?

Sherryl: How do we tell the difference between Parkinson's-related dementia and other types of dementia?

Dr Walker: People with Parkinson's dementia and dementia with Lewy bodies have a number of symptoms and signs that are rare in people with Alzheimer's disease - the most common type of dementia.

In addition to motor problems, people with Parkinson's tend to have greater impairment of attention, orientation in and negotiation of environment. They are also less flexible in their way of thinking.

They do have memory problems but these are not as severe as in people with Alzheimer's disease.

Compared to Alzheimer's disease they tend to fluctuate more in their attention, cognition, and ability to do things. And they have frequent visual hallucinations and sometimes false fixed ideas.

They have a sleep disturbance that is not seen in people with Alzheimer's disease and can be very sensitive to neuroleptic (antipsychotic) drugs.

Anonymous: How is dementia diagnosed?

Dr Walker: If a doctor suspects dementia, s/he will usually perform a physical examination and arrange for blood and urine tests to exclude other possible reasons for cognitive difficulties. Some GPs will then make a referral to a specialist.

The specialist usually takes a careful history of cognitive problems, checks if the person has any psychiatric problems, and performs some cognitive testing.

The extent of cognitive testing depends on the severity of the cognitive impairment and how complex the case is. They might also arrange a brain scan called an MRI or CT.

To make a diagnosis of dementia a person has to have sufficiently severe cognitive problems to affect their everyday activities independent of the effect of their motor symptoms.

It can sometimes be challenging to distinguish between difficulties that are due to motor and psychiatric problems or problems with the autonomic system (which controls basic involuntary bodily functions such as sweating, digestion and heart rate) and those that are due to cognitive problems.

Sometimes a referral is made to a memory clinic.

turnip: Is dementia caused by the lack of dopamine resulting in the death of cortex cells, or is the mechanism that is killing dopaminergic cells also killing cortex cells?

Dr Walker: The spread of Lewy bodies into the cortex - the outer parts of the brain that are involved in thinking - are likely to be the primary reason for dementia in people with Parkinson's.

Lewy bodies are sticky clumps of proteins found inside the nerve cells that are lost in Parkinson's. As they spread into other brain areas, Lewy bodies prevent nerve cells communicating properly, cause loss of the neurotransmitter acetylcholine, and ultimately cause nerve cell death.

However, the loss of nerve cells and dopamine in deep brain structures (basal ganglia) can also cause some thinking and memory problems.

And in some cases Alzheimer's-like changes are also present and contribute to dementia.

kittyw: What is the actual difference between Parkinson's dementia and Lewy body dementia, other than the order of onset, since Lewy bodies seem to be implicated in Parkinson's dementia?

If both amount to the same in the end, why does it matter which comes first?

Dr Walker: Originally people thought that Parkinson's dementia was due to coincidental Alzheimer's disease and that dementia with Lewy bodies was due to cortical Lewy bodies (Lewy bodies in the cortex - the outer parts of the brain involved in thinking).

With time, it became clear that both are due to cortical Lewy bodies, loss of brain cells and synapses and loss of the neurotransmitter acetylcholine, with a variable amount of Alzheimer's pathology.

However, clinicians still think that it is useful to distinguish the two conditions despite the fact that the pathology or the underlying cause is the same.

The current practice is to differentiate these two based on the timing of the onset of motor symptoms.

Parkinson's dementia is diagnosed if the onset of dementia occurs a year or more after the onset of motor symptoms.

Dementia with Lewy bodies is diagnosed when dementia is present before, simultaneously with or within one year of the onset of motor symptoms.

The one year cut-off is an arbitrary period and some clinicians use a cut-off period of 3 years.

superjanet: My husband was diagnosed with Parkinson's around 13 years ago, and is now 73. Over the past couple of months he has been seeing vivid hallucinations.

Our Parkinson's nurse suggested that these could be due to the medication or to the condition, and recommended we started to reduce the amount of Mirapexin he was taking. Unfortunately this did not seem to have much effect on the hallucinations, but did lead to a loss of mobility.

Is it more likely that the hallucinations are part of the onset of dementia rather than caused by the medication? If so, will it be possible to control them with the use of anti-psychotic medication?

Dr Walker: The development of hallucinations is part of the interaction between the condition and the medication.

In the early stages most people can tolerate medication without getting hallucinations but later on some start to hallucinate even when they are on the same or a reduced amount of medication.

People with hallucinations can go on to develop dementia. Hallucinations are not always easy to treat. Treatment with rivastigmine can be helpful particularly if they also have dementia.

Dot: What are the risks for someone with Lewy body dementia and Parkinsons having a surgery on an aortic aneurism?

Dr Walker: Surgery on an aortic aneurism (a bulging or swelling of the aorta) is a big operation for any patient.

People with Parkinson's disease dementia and dementia with Lewy bodies are more likely to become acutely confused after any operation, particularly if they are on rivastigmine which has to be stopped for the duration of the operation.

Jackie: Can Parkinson's-related dementia be prevented or slowed down?

Dr Walker: There is evidence that treatment with rivastigmine can greatly improve the symptoms of dementia for a period of time.

withy: My husband had a DaTSCAN 12 months ago when Parkinsons on one side only was diagnosed. His consultant now says that he thinks he has Parkinson's with Lewy bodies.

Would the dementia with Lewy bodies not have shown up on his scan?

Dr Walker: Everyone with Parkinson's, without or with dementia, has an abnormal DaTSCAN.

When looking at a DaTSCAN one can only say if it is normal or abnormal. It is not possible to see whether the person has dementia or not.

Dementia is diagnosed by clinical examination. A normal DaTSCAN excludes Parkinson's, Parkinson's dementia and dementia with Lewy bodies.

withy: My husband's consultant recently said he thinks my husband has Parkinson's with Lewy bodies. Are the symptoms different to Parkinson's dementia?

If so is the treatment different, is there in fact any treatment available?

Dr Walker: Only a small minority of people with Parkinson's do not have Lewy bodies.

In the early stages they are mainly in the middle part of the brain, but later they spread to other brain areas. The doctor perhaps meant that your husband now has more widespread Lewy bodies and is developing Parkinson's dementia.

There are some additional medications that are used in patients with Parkinson's dementia that improve the symptoms of dementia.

There are treatments available to control the symptoms. The most commonly used medication is rivastigmine. Rivastigmine has a positive effect on cognitive functions, behavioural symptoms and everyday activities.

poorna: Is dementia inevitable in early onset Parkinson's?

Dr Walker: No. Dementia is less common in the initial stages of early onset Parkinson’s.

However with increasing age, the chance of developing dementia goes up. The likelihood of developing dementia also increases as the disease advances.

emswife: Is it possible to predict who might go on to develop dementia? Is there any research into biomarkers etc?

Dr Walker: There are some emerging imaging techniques and other biomarkers but none are at present used in clinical practice.

Eileen: What is the best way for a carer to deal with hallucinations in a person with Parkinson's ?

Dr Walker: People are more likely to experience hallucinations when they are inactive and bored and a stimulating environment reduces hallucinations.

Therefore, if possible, it is good to keep the person active and engaged in social and leisure activities. Sometimes it is helpful to reassure the person experiencing them that the hallucinations are only a trick of their mind.

Parkinson's UK: Take a look at our Hallucinations and delusions in Parkinson's information sheet for more information about this topic.

Emma: More and more, I am seeing rivastigamine being prescribed by consultants for the management of hallucinations in people with Parkinson's (without the diagnosis of a formal dementia) almost as an anti-psychotic. The effects have been varied but it usually helps.

What are your thoughts on this?

Dr Walker: Rivastigmine is an anti-dementia medication that improves the symptoms of dementia.

There is also evidence that it reduces visual hallucinations in people with Parkinson's and dementia with Lewy bodies.

Rivastigmine is sometimes given with good results to people with Parkinson's who do not have dementia, but who have distressing visual hallucinations.

The other medications that are used for hallucinations are anti-psychotic drugs but they can have unpleasant side effects and can make motor symptoms worse.

Claire: My Dad was diagnosed with Parkinson's approximately 9 years ago. He is now awaiting the results of a brain scan to see if he has dementia with Lewy bodies. 

Is his life expectancy shorter if he has dementia with Lewy bodies?

Dr Walker: Your doctor is most probably waiting for a scan to rule out other causes of dementia.

If he is diagnosed with dementia he will have Parkinson's dementia not dementia with Lewy bodies as the onset of dementia was many years after he first developed Parkinson's.

People with Parkinson's dementia can have a shorter life expectancy, but this varies in individual cases.

If he has Parkinson's dementia then his doctor might consider giving him a medication called rivastigmine to improve his dementia symptoms.

Louis: What is the percentage of people with Parkinson's that go on to develop dementia? Or, what are the chances?

Dr Walker: About 50% of people with Parkinson's develop dementia within 8 years of being diagnosed. Most of the people affected are of advanced age.

The time from being diagnosed with Parkinson's to the onset of dementia varies greatly in individual cases.

Research shows that 80% of patients who have had Parkinson's for 20 years or more will have developed dementia.

What next?

Developing Parkinson's dementia or dementia with Lewy bodies is not inevitable.

Having memory problems, hallucinations or other symptoms mentioned here does not necessarily mean that you have dementia or will go on to develop it. These symptoms can be caused by other health issues.

If you are concerned, contact your GP or Parkinson's nurse who can offer advice or refer you to a specialist.

A diagnosis of dementia can be very significant both for the person with the condition and for their carers and family members.

If you are diagnosed with Parkinson's dementia or dementia with Lewy bodies, there are treatments available to help with the symptoms.

There are also a range of professionals that can help you to manage day-to-day including physiotherapists, occupational therapists, speech and language therapists and dietitians. Your GP, specialist or Parkinson's nurse can refer you to these healthcare professionals.

If you are caring for someone with dementia, our information sheets give practical advice to help you manage:

• Parkinson's dementia information sheet
• Dementia with Lewy bodies information sheet

Further information and support for all aspects of dementia is available from the Alzheimer's Society helpline 0845 300 0336.

About Dr Walker

Dr Zuzana Walker, FRC Psych, MD, is a Reader in Psychiatry of the Elderly at University College London, UK.

She is the lead consultant in the West Essex Neurocognitive Clinic, which has been running since 1993.

Her main areas of interest are:

• dementia with Lewy bodies
• Parkinson's dementia
• functional and molecular neuroimaging
• postmortem validation of clinical and imaging findings
• new treatments for mild cognitive impairment, Alzheimer's disease and Parkinson's dementia

Zuzana has published a number of key papers on neuroimaging of the dopamine transporter in dementia with Lewy bodies and Parkinson's.

And she's a member of the European Association of Nuclear Medicine Neuroimaging Committee and of the National Dementia Clinical Study Group in the UK.

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