Breath test for Parkinson's disease

Experts believe that a simple breath test could help doctors detect and diagnose Parkinson's disease.

The test looks for a unique signature of chemicals in exhaled breath.

Small studies in volunteers have begun and early findings suggest the test can identify those with the debilitating brain condition.

Larger trials are now planned to see if it could truly be a useful test, particularly for picking up Parkinson's in its earliest stages.

Currently, no test can conclusively show that a person has Parkinson's.

Instead, doctors reach a diagnosis based on a person's symptoms and test results - such as brain scans to rule out other diseases.

At this stage, Parkinson's may already be fairly advanced.

Identifying it earlier would be beneficial because it would mean treatment could be given sooner.

Sniff it out

Parkinson's disease is a progressive condition where there is gradual loss of nerve cells from the brain.

And it is thought that this degradation leaves a chemical footprint in the body that could potentially be used in diagnostic tests.

A scan showing tell-tale brain degeneration in a patient with Parkinson's

Scientists have been exploring different ways of finding such biomarkers, including looking in blood, spinal fluid, and exhaled breath.

The breath analyser was developed by Prof Hossam Haick and his team at the Technion Israel Institute of Technology

It looks for traces of volatile organic compounds or VOCs in the air we exhale.

In a small trial in Israel with 57 people, some with Parkinson's and some without, the test could identify the individuals with Parkinson's by looking for distinctive patterns of VOCs.

It also appeared to distinguish between different sub-types of the disease based on the presence and quantity of different VOCs.

The charity Parkinson's UK and experts at the University of Cambridge were intrigued by these early findings and are now setting out to do a bigger study involving 200 volunteers from England.

Dr Simon Stott, who is part of this UK team and will be working alongside the scientists from the Israel Institute of Technology, in Haifa, said: "We would like to find biomarkers that can identify patients early.

"A breath test would be really appealing because it's non-invasive, non-painful and can be done in seconds.

"While it wouldn't replace what doctors already do, it could be a useful diagnostic tool to help them."

The biggest hope is that there may be molecules in the breath of people with Parkinson's which throw up new options for drug targets.

The researchers say they have many years of work ahead of them before they will know if the test can be used in clinics.

Parkinson's disease

• One in 500 people in the UK has Parkinson's

• A combination of genetic changes and environmental factors may be responsible for the condition

• There are different sub-types of the disease and they share the symptoms of tremor, muscle rigidity and slowness of movements.