February 12, 2015

Diagnosing Parkinson's from a Simple Puff of Breath?

What if doctors could detect and diagnose a patient’s Parkinson’s disease – early on – with just a simple breath test?

It may sound a bit like science fiction, but the technology has shown promise, and more testing is underway.

In 2015, there is no useful diagnostic tool for PD. Doctors might detect the disease based on their patients’ symptoms -- like tremor, stiffness and difficulty with movements and speech. Test results might lead to diagnoses. 

But these techniques often don’t’ ID the disease early enough, and they aren’t foolproof. In fact, studies have shown that up to 20% of people diagnosed with Parkinson's show no evidence of the disease in post-mortem examinations.

The Curse of Late PD Diagnoses
Millions of others – like me – don’t get a proper, formal PD diagnosis until long after the disease has begun to do its destructive work on the brain’s dopamine-producing neurons.

In my own case, one arm wasn’t swinging normally – evidence that some Parkinson’s-related stiffness was already setting in. I also lost my sense of smell – a common early-warning sign -- long before any of my doctors spoke the word “Parkinson’s” to me.

There’s no question: the current absence of a reliable, useful PD diagnostic tool puts people with Parkinson’s (PWPs) at a real disadvantage. Some estimates suggest that up to 80% of PWP’s dopamine levels have been lost before diagnosis. In those advanced cases, therapy becomes mostly a matter of damage control.

Take a Deep Breath
Scientists believe that the degradation of nerve cells in the brains of PWPs leaves a kind of chemical footprint in the body… a biomarker which an appropriate test might be able to indentify. Find that biomarker early enough, and useful, symptom-thwarting treatment could begin right away.

Researchers have been searching for PD biomarkers for a long time – in blood, brainscans, and spinal fluid.

And now, they’re looking at exhaled breath for traces of certain volatile organic compounds (VOCs).

This search for a Parkinson’s-breath connection isn’t brand new, but an article posted on February 10 to the BBC’s website alerted me that new developments were underway.

A small Israeli study examined the breath of 57 people – some of whom had PD. Study leaders concluded they could:
  • ID the PWPs through distinctive patterns of VOCs, and
  • Even distinguish between different sub-types of the disease based on the presence and quantity of different VOCs.

 Now, a Larger Study
The Israeli study got the attention of the British charity Parkinson’s UK and researchers at the University of Cambridge. Together, they plan to conduct a larger study, hoping to replicate the Israeli results with 200 volunteers in England.

Dr Simon Stott – a member of the British team that will collaborate with scientists from the Israel Institute of Technology, in Haifa – said: "A breath test would be really appealing because it's non-invasive, non-painful and can be done in seconds.”

In addition to enabling earlier diagnoses for PWPs – in itself a potential game-changer in the treatment of the disease – there’s the hope that these volatile organic compounds in the breath of PWPs will create new targets for drug development.


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Next week, we’ll consider another potential PD diagnostic tool in the works – an amazing smartphone app.

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