Parkinson’s disease is the second most common neurological problem in the world. In Australia 150,000 people are living with the debilitating condition and a further 50 are diagnosed every day.
Symptoms of Parkinson’s include slow movement, rigidity and tremor. Before these symptoms develop, there is a period of rapid eye movement sleep behaviour disorder (RBD). This is an important predictor for developing Parkinson’s disease later in life.
In game-changing research, scientists at The Florey Institute and Austin Health have found ways to detect tell-tale signs of Parkinson’s disease up to 30 years before symptoms appear. In addition, a European team has developed a blood test which predicts the onset of Parkinson’s symptoms up to seven years in advance
Florey Professor Kevin Barnham said Parkinson’s is often thought of as an illness of old age, when in fact it starts in midlife and can go undetected for decades.
“Parkinson’s disease is very hard to diagnose until symptoms are obvious, by which time up to 85 per cent of the brain’s neurons that control motor coordination have been destroyed. At that point, many treatments are likely to be ineffective,” he said.
“Our long-term goal is to find a way to detect the disease much earlier and treat people before the damage is done.”
Professor Barnham and colleagues found that tracking a biomarker called F-AV-133 with Pet (positron emission tomography) scans can track degeneration of nerve cells leading to diagnose Parkinson’s.
The team scanned 26 patients with Parkinson’s disease, a control group of 12 people, and 11 people with Rapid Eye Movement sleep behaviour disorder.
Each person was PET scanned twice, two years apart.
None of the participants had significant changes in clinical symptoms of Parkinson’s using currently available assessments. However, the PET scans showed significant loss of neurones in three key regions of the brain in patients with the condition.
A mathematical model using data from this trial showed about 33 years’ of slow neuronal loss occurs in Parkinson’s. This loss occurs for about 10 years before the disease is detectable on a PET scan. Even then it will be a further six and a half years before the onset of motor symptoms.
Following the onset of physical symptoms, there are about a further three years until a clinical diagnosis can be confirmed. This means neurons are lost more than 22 years before symptoms are sufficient for diagnosis.
Professor Barnham said the findings open pathways to developing screening protocols for diagnosing and treating Parkinson’s disease up to 10 years earlier than is currently possible.
Another team at Great Ormond Street Hospital, London and the University of Göttingen, Germany, found that certain proteins in the blood may predict Parkinson’s disease up to seven years before the onset of motor symptoms.
Dr Jenny Hällqvist and colleagues analysed blood samples from 99 individuals recently diagnosed with Parkinson’s disease, 72 individuals with Rapid Eye Movement sleep behaviour disorder but no motor symptoms of Parkinson’s 36 healthy controls.
They identified 23 proteins that increased in the blood of people with Parkinson’s disease. Of these proteins, six were also found in individuals with RBD. The authors then applied a machine learning model to predict diagnosis based on blood protein composition. The model identified all individuals with Parkinson’s disease based on the presence of eight proteins.
The model also predicted which individuals with RBD that would go on to develop Parkinson’s disease with 79 per cent accuracy up to seven years before the onset of symptoms.
Dr Jade Kenna, lecturer in neuroscience at Notre Dame University, emphasised that no early test was yet available to GPs.
“More than 70 per cent of motor neurones are irreversibly damage by the time a diagnosis can be made based on motor symptoms,” she said.
“There are no approved treatments for earlier diagnosed Parkinson’s patients, but exercise, especially dancing and boxing which also have a social side and eating a varied diet with lots of fruit and vegetables are likely to be helpful.
“My research shows that the gut biome plays a major role in predicting the onset of Parkinson’s, so good nutrition is a key to delaying onset of the condition,” she said.
Identifying individuals with early Parkinson’s disease could also provide more subjects for clinical trials. This should improve both patient treatment options and research output.
