Researchers believe they’ve pinpointed a new way to identify Alzheimer’s or Parkinson’s diseases: through a skin test that can detect levels of tau protein, which is associated with the development of the degenerative disorder.

The study suggests that skin, which originates from the same form of tissue as the brain in embryos, can hold information about abnormal tau proteins. Their results will be presented at the American Academy of Neurology’s 67th Annual Meeting in Washington, D.C.

“Until now, pathological confirmation was not possible without a brain biopsy, so these diseases often go unrecognized until after the disease has progressed,” Dr. Ildefonso Rodriguez-Leyva of Central Hospital at the University of San Luis Potosi in Mexico said in the press release. “We hypothesized that since skin has the same origin as brain tissue while in the embryo that they might also show the same abnormal proteins. This new test offers a potential biomarker that may allow doctors to identify and diagnose these diseases earlier on.”

The researchers took skin biopsies from 20 people who had Alzheimer’s disease, as well as from 16 people who had Parkinson’s and 17 who had dementia. They compared them to 12 healthy people who were in the same age group. They found that people who had both Alzheimer’s and Parkinson’s had levels of tau protein 7 times higher than healthy participants. Those with Parkinson’s had 8 times higher levels of alpha-synuclein protein compared to the healthy people.

There is currently no single test to identify and diagnose Alzheimer’s. Doctors will typically have a patient undergo a complete medical assessment to be diagnosed, including a medical history, mental status testing, blood tests and brain imaging. But scientists have been working on discovering biomarkers of the disease that would allow patients to be diagnosed earlier, and potentially treated.

Whether the skin test will prove to be useful in identifying the diseases in a clinical setting has yet to be further investigated.

“More research is needed to confirm these results, but the findings are exciting because we could potentially begin to use skin biopsies from living patients to study and learn more about these diseases,” Rodriguez-Leyva said in the press release. “This also means tissue will be much more readily available for scientists to study. This procedure could be used to study not only Alzheimer’s and Parkinson’s, but also other neurodegenerative diseases.”