Earwax Test Accurately Detects Parkinson’s by Identifying Odor Molecules

Current tests for Parkinson’s disease (PD) rely heavily on clinical scales and neuroimaging, which are often subjective, expensive, and ill-suited for routine screening. Since most treatments only slow disease progression, early diagnosis is critical for effective care. Now, researchers have developed a novel and affordable screening system that detects PD from the volatile organic compounds (VOCs) found in a person’s earwax.

This innovative approach from researchers at Zhejiang University (Hangzhou, China;) was the result of a study to explore the diagnostic potential of sebum-rich earwax as a more stable and protected source of VOCs linked to Parkinson’s. The idea builds on earlier findings that sebum composition changes in PD due to neurodegeneration, inflammation, and oxidative stress, resulting in a distinctive odor profile. Unlike facial sebum, which is exposed to external environmental conditions such as humidity and air pollution, earwax remains relatively uncontaminated, making it a reliable testing medium. To investigate this, the researchers collected earwax samples by swabbing the ear canals of 209 individuals, including 108 people diagnosed with PD. Using gas chromatography and mass spectrometry, they identified four VOCs that were significantly different in people with Parkinson’s: ethylbenzene, 4-ethyltoluene, pentanal, and 2-pentadecyl-1,3-dioxolane. These VOCs emerged as potential biomarkers for the disease.

Image: Ear wax could be a possible screening medium for Parkinson’s disease (Photo courtesy of 123RF)

Based on this dataset, the team developed an artificial intelligence olfactory (AIO) system trained to detect PD by analyzing the VOC patterns. When tested, the AIO-based model demonstrated 94% accuracy in distinguishing between PD and non-PD samples, according to the ACS’ Analytical Chemistry report. The high level of precision highlights the system’s potential for early detection, especially since the test is non-invasive and inexpensive. This new AIO screening tool could serve as a first-line diagnostic method to catch PD in its earliest stages, well before traditional symptoms appear. By enabling earlier medical intervention, it may improve long-term care outcomes for patients and streamline diagnosis in both clinical and community healthcare settings.

“This method is a small-scale single-center experiment in China,” said researcher Hao Dong from Zhejiang University. “The next step is to conduct further research at different stages of the disease, in multiple research centers and among multiple ethnic groups, in order to determine whether this method has greater practical application value.”