27th June 2006(Daily Mail) - Scientists have developed a new
scanning technique for Parkinson's disease, offering hope that many
patients who may have been wrongly diagnosed will be able to start
treatment earlier.
Previously, neurologists have had to rely on visual checks and a
patient's medical records to determine whether they suffer from the
illness.

People with Parkinson's generally suffer from uncontrollable shaking
limbs — known as tremors — but this can be mistaken for a much less
serious condition known as essential tremor.

A report published several years ago revealed that up to 20 percent
of people diagnosed with essential tremor actually had Parkinson's.
(Around 120,000 people in the UK have the condition.)

Now, misdiagnosis of the disease should become a thing of the past
as the new scanning technology is almost 100 percent accurate.

Patients are injected with a radioactive dye which travels to the
brain and is picked up on a screen by a camera called SPECT (Single
Photon Emission Computed Tomographic imaging).

"If you have Parkinson's disease it will show up as a bright area in
the brain, whereas the non-diseased area will be a duller colour,"
explains Dr Stuart Jamieson, a neurologist at Leed's Royal Infirmary
who has a specialist interest in the disease.

Although to an experienced doctor working with Parkinson's patients
the difference between that disease and essential tremor ought to be
clear, many patients are not diagnosed by a neurologist and some are
actually diagnosed by their GP.

"Being told you have essential tremor and then discovering several
years down the line that you actually have Parkinson's can be very
distressing for some patients," says Dr Jamieson.

"Parkinson's can be a long and drawn out decline over as long as 20
years. So you want an accurate diagnosis of your symptoms. Essential
tremor, although a severe nuisance to sufferers, is not a
neurological disease. So when you scan a patient with it, the brain
does not have the changes you see in Parkinson's.

"The main way of distinguishing between the two is that patients
with essential tremor have it in their limbs on both sides of the
body, whereas someone with Parkinson's is likely to have shakes down
just one side."

The diagnostic DaTSCAN is performed three hours after an injection
of radioactive dye. The scan itself lasts half an hour and is done
on an outpatient basis.

The technology has previously been available privately, but is now
being introduced in the NHS.

Parkinson's is caused by a chemical imbalance in the co-ordination
centre of the brain, known as the striatum.

Patients suffer from cell death in an area of the brain called the
substantia nigra, which produces the chemical dopamine.

As the cells die, less dopamine is produced and transported to the
striatum, resulting in co-ordination problems.

Later in the disease, cells in other portions of the brain and
nervous system also degenerate.

William Frodsham, from Yeadon near Leeds, was one of the first
patients to have a DaTSCAN four years ago.

The 57-year-old had been diagnosed as suffering from Parkinson's
eight years ago by Dr Jamieson. But the disease appeared so mild and
under control that Dr Jamieson began to doubt he had Parkinson's.

"Even experienced clinicians like myself can make mistakes in
diagnosis, and because William was so well, I thoughtI might have
got it wrong," he says.

"Unfortunately for William, my diagnosis was right. But it was
important to set my mind at rest and that's where this scanning
technology works so well. If you are uncertain, you can always fall
back on it for help."

William, who works for a skip hire firm, has his tremors kept under
control by medication and is able to lead a near-normal life at
present.

"I was sort of hoping that Dr Jamieson had initially got it wrong
when he ordered a scan. But to be truthful, my Parkinson's isn't all
that bad at present.

"They say keeping healthy and active is good for controlling the
disease. I run, swim and play golf and that seems to help. I have my
bad days, but most of the time I am able to put it in the
background."

Specialists such as Dr Jamieson believe that even without the new
scanning technique, diagnosing Parkinson's would be more accurate if
all suspected cases were seen by a hospital consultant. At present,
one in five cases of Parkinson's is diagnosed by a GP with no real
specialist knowledge of the disease.

"Misdiagnosis is more likely to happen in such circumstances, or if
a patient sees a consultant in care of the elderly rather than a
neurologist," says Dr Jamieson.

This view is supported by the Parkinson's Disease Society which
wants to see an end to GPs diagnosing the condition.

"They don't have the knowledge and it is inappropriate for them to
get involved in a very expert area," says Kieran Breen, policy
director of the society.

"We even have GPs diagnosing and initiating treatment, which is not
a good idea. The dosing of patients with Parkinson's is complex and
needs to be in the hands of a specialist."

New guidance for doctors from the National Institute for Clincial
Excellence (NICE) due out tomorrow is expected to recommend that
Parkinson's is diagnosed by hospital doctors only.


MARTYN HALLE