Scientists say they have
found a way to distinguish between different types of dementia without
the need for invasive tests, like a lumbar puncture.
US experts could accurately identify
Alzheimer's
disease and
another type of
dementia from structural
brain patterns on
medical
scans,
Neurology reports.
Currently, doctors can struggle to
diagnose dementia, meaning the most appropriate
treatment may be delayed.
More invasive tests can help, but are unpleasant for the
patient.
Distinguishing features
Despite being two distinct diseases,
Alzheimer's and frontotemporal dementia, share similar clinical features
and symptoms and can be hard to tell apart without medical tests.
Both cause the person to be confused and forgetful and can affect their personality,
emotions and
behaviour.
Alzheimer's tends to attack the
cerebral cortex - the layer
of grey matter covering the
brain - where as frontotemporal
dementia, as
the name suggests, tends to affect the
temporal and
frontal lobes of
the
brain, which can show up on
brain scans, but these are not always
diagnostic.
A
lumbar puncture - a needle in the spine - may also be used
to check protein levels in the
brain, which tend to be higher in
Alzheimer's than with frontotemporal
dementia.
A team at the University of Pennsylvania set out to see if
they could ultimately dispense of the
lumbar puncture test altogether
and instead predict
brain protein levels using
MRI brain scans alone.
They recruited 185
patients who had already been
diagnosed
with either
Alzheimer's
disease or frontotemporal
dementia and had
undergone a
lumbar puncture test and
MRI scanning.
The researchers scrutinised the brain scans to
see if they could find any patterns that tallied with the protein level
results from the lumbar puncture tests.
They found the density of gray matter on the
MRI scans correlated with the protein results.
The
MRI prediction method was 75% accurate at identifying the correct
diagnosis.
Although this figure is some way off an ideal 100%, it could still be a useful
screening tool, say the
researchers.
Lead
researcher Dr Corey McMillan said: "This could be used
as a
screening method and any borderline
cases could follow up with the
lumbar puncture or
PET scan."
Dr Simon Ridley, Head of
Research at
Alzheimer's
Research UK,
said: "This small
study suggests a potential new method for
researchers
to distinguish between two different types of
dementia, and a next step
will be to investigate its accuracy in much larger
studies involving
people without
dementia.
"While this method is not currently intended for use in the
doctor's
surgery, it may prove to be a useful tool for
scientists
developing new
treatments. The ability to accurately detect a
disease is
vital for recruiting the right
people to
clinical trials and for
measuring how well a
drug may be working.
"Ultimately, different causes of
dementia will need different
treatment approaches, so the ability to accurately distinguish these
diseases from one another will be crucial."
The only drug currently licensed in England and Wales for treating frontotemporal
dementia is rivastigmine.
There are four licensed
treatments for
Alzheimer's -
donepezil,
galantamine,
rivastigmine and
memantine.
Dementia
- There are many causes of dementia, with Alzheimer's the most common
- More than half a million people in the UK have Alzheimer's disease
- Frontotemporal dementia tends to affects people who are younger - under 65 - and can affect a personality and behaviour
- Other types of dementia include vascular dementia and dementia with Lewy bodies