Å®ÉúСÊÓƵ

Husbands and wives of people with Parkinson’s disease have been found
to share some of the disabilities of the disease. Long-term partners of
patients display mild forms of the shuffling gait, taut muscles and hunched
posture regarded as classic signs of Parkinson’s disease. The effect is
so small, however, that it is usually undetectable.

Parkinson’s mostly affects people over 50, and about one person in every
thousand has the disease. Its cause is a reduced level of the neurotransmitter
dopamine, but the only accepted way of diagnosing it is by its outward signs.

Researchers from Northwick Park Hospital in London and the Medical Research
Council’s Clinical Research Centre subjected 20 Parkinson’s patients and
their spouses to a battery of tests that quantified these signs. They also
studied a control group of 20 unaffected couples.

The results, published in this month’s Age and Ageing, show that the
posture, gait and degree of muscle tension of the spouses of Parkinson’s
patients were significantly different from controls. The variation was not
significant for the fourth classic sign of Parkinson’s disease – tremor
of the hands.

The Northwick Park team used much finer measurements than normal to
detect ‘microsigns’ of disease. For example, to characterise a person’s
gait they measured stride length and two angles through which the ankle
can flex.

It is not clear yet whether the microsigns found in spouses of Parkinson’s
patients are symptoms of a mild form of the disease or a manifestation of
some other effect. People who live together often display similar patterns
of behaviour. ‘If you walked alongside somebody with a shorter stride, you’d
adopt a shorter stride,’ says Nick Bateman of the University of Newcastle
upon Tyne.

This notion is refuted by Sylvia Dobbs, the clinical pharmacologist
who leads the research. She says that the unusual angles through which the
ankles turn are measures of the damage done by disease to the joint, and
that this is something people cannot imitate.

Dobbs believes that three factors contribute to Parkinson’s – old age,
an environmental ‘insult’ and genetic susceptibility. If two people of the
same age are exposed to the same insult, one may develop Parkinson’s more
quickly than the other because of genetic differences.

‘Spouses shouldn’t be alarmed about living with sufferers,’ says Dobbs.
The tendency, she says, is simply ‘a marker of a shared environmental insult’.

The team is designing tests to quantify other signs of Parkinson’s.
Once these tests are developed, Dobbs and her colleagues hope they will
be able to screen apparently healthy people for the disease.

‘There is good evidence that Parkinson’s starts many years before the
disease gets overt,’ says Donald Calne, director of the Neurodegenerative
Disorder Centre in Vancouver, Canada. He points to studies by neurologists
of old film footage of Adolf Hitler in which he becomes progressively disabled.

At least one drug available now is thought to delay the progress of
Parkinson’s disease. A cheap, early screening test would be valuable, says
Calne, and fashionable science such as genetics has failed to produce one.
Although the work at Northwick Park needs to be repeated, it ‘has not had
its fair share of the limelight’, he says.