Parkinson's disease is a progressive neurodegenerative disorder and despite decades of intensive research, there is still no drug or reliable diagnostic test. However, with the help of a woman with a particularly strong sense of smell, scientists have discovered how Parkinson's disease changes the human odor. They hope that this discovery can help with an early diagnosis.
Currently, treatment cannot start until motor symptoms such as tremor and stiffness appear. However, the breakdown of nerve tissue starts about 6 years before people notice clinical signs. Finding a reliable way to diagnose Parkinson's disease would mean that treatment could begin earlier and keep the disease at bay.
Doctors have been using the scent as a diagnostic tool for centuries. For example, some people claim that scopulosis is similar to stale beer, while typhoid fever causes a smell reminiscent of baked bread. Until recently, there was no odor associated with a neurodegenerative disorder of any kind.
Joy Milne can feel Parkinson's disease
Joy Milne belongs to people who are hypersensitive to aroma and can distinguish them very well. In 1986, doctors diagnosed Parkinson's disease in her husband, and since then Joy has been able to distinguish the specific odor associated with the disease.
Recently a group of researchers together with Joy Milne tried to distinguish which chemicals can cause this odor. The findings were recently published in a journal ACS Central Science.
First the researchers had to determine where the odor came from. They noticed that she was most intense on her upper back and forehead, but not in her armpit. This means that the smell is probably not from sweat, but from sebum that produces sebaceous glands in the skin.
Scientists already know that there is an increase in seborrhea, called seborrhea, in Parkinson's disease. Scientists led by Perdita Barran tried to understand which chemicals in sebum can cause odor changes.
He collected samples of tallow from the upper back of 60 people. Some people have Parkinson's disease and others do not.
Using mass spectrometry, scientists analyzed sebum samples to identify any chemicals that were elevated in people with Parkinson's disease. They have shown that there is a significant difference between volatile chemicals in the serum of people with Parkinson's disease and healthy people. As it turned out, three compounds play an important role in a certain aroma: hippuric acid, eicosanoic acid and octadecanal.
Importantly, there were no significant differences between people with Parkinson's, whether they were taking medication or not. This means that the change in odor is probably not due to the treatment. After giving these chemicals to Joy Milne, she was able to identify the "musky" aroma of Parkinson's disease.
Scientists have conducted this study with a limited number of participants, so they will have to continue their work. However, they hope that this is a unique way to detect Parkinson's disease much earlier than is currently possible.
Why does smell change?
Researchers have not designed their research to find out why serum concentrations of these three substances are elevated in people with Parkinson's disease. However, the authors discuss some possible causes.
For example, previous studies have confirmed that there are connections between various skin conditions and Parkinson's disease. These include, for example, Malassezia spp.
According to the study authors these changes in yeast and bacterial populations can change the skin microflora and physiology by methods that are "very specific" for Parkinson's disease.
These findings open up new possibilities for Parkinson's disease and can also provide a new insight into how this condition develops.