New research reveals that tears may indicate how susceptible people may be for developing Parkinson's disease. Analyzing tear samples allowed scientists to get a glimpse into one of the differences found in people that have Parkinson's.

Clues In Tears

With the findings of the study, doctors may soon have a new way of diagnosing Parkinson's in their patients. A study by a group from the University of Southern California (USC) shows that people with Parkinson's have different levels of a protein associated with the disease than those who don't have it.

Tears were examined because of their link to the nervous system. Parkinson's disease itself is a degenerative order that affects the central nervous system. Tears were found to contain proteins produced by secretory cells from the tear gland, which is stimulated by nerves to turn these proteins into tears.

This would provide doctors with reliable and non-invasive biological marker for the disease. Parkinson's disease develops over time, even before symptoms begin to appear. Knowing if it can be detected before these symptoms appear may give doctors and scientists a way to fight it before the nervous system starts breaking down.

Tear Study

Researchers collected tear samples from 55 people with Parkinson's disease and compared them with tear samples from 27 people who did not have the disease. Those without the disease were the same age and gender as those that do have Parkinson's. Tear samples were then analyzed for four specific proteins.

Scientists found that those with Parkinson's have lower levels of the alpha-synuclein protein in their tears. The samples also had a higher level of the aggregated -- clumped, misfolded versions of the protein -- form of alpha-synuclein, oligomeric alpha-synuclein. Oligomeric alpha-synuclein is linked with the death of cells in the nervous system.

This research shows that there may be a link with tear gland secretory cells and the alpha-synuclein that is found in tears. This is just an initial investigation into a new method that could be used to detect Parkinson's. It still isn't a definitive way to prove that those with higher levels of oligomeric alpha-synuclein are more likely to have Parkinson's.

Parkinson's disease affects around one million Americans and more than 10 million people worldwide. Almost 60,000 Americans are diagnosed with Parkinson's disease each year. There have also been links between Parkinson's and sleeping disorders.