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
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
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
People with Parkinson's dementia and dementia with Lewy bodies have a number of symptoms that are rare in people with Alzheimer's - the most common type 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
Alzheimer's disease - the most common type of
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
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
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
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
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
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
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
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
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
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
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
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
Dr Walker: There is evidence that treatment with rivastigmine
can greatly improve the symptoms of dementia for a period of
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
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
withy: My husband's consultant recently said he thinks my husband
has Parkinson's with Lewy bodies. Are the symptoms different to
If so is the treatment different, is there in fact any
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
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
poorna: Is dementia inevitable in early onset
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
Dr Walker: People are more likely to experience hallucinations
when they are inactive and bored and a stimulating environment
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
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
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
Developing Parkinson's dementia or dementia with Lewy bodies is not inevitable.
But if you are diagnosed with dementia, there is support available.
Developing Parkinson's dementia or dementia with Lewy bodies is
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
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
If you are diagnosed with Parkinson's dementia or dementia with
Lewy bodies, there are treatments available to help with the
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
If you are caring for someone with dementia, our information
sheets give practical advice to help you manage:
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
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.
More about dementia and Parkinson's