The short version
- Two University of Connecticut studies, with 89 and 82 participants, found higher blood levels of the inner-ear protein prestin in people with chronic tinnitus than in people without it.
- In the second study the gap held after adjusting for age, hearing thresholds and a week of measured noise exposure, and three other ear proteins showed no difference.
- The test is not accurate enough to diagnose tinnitus, and both studies are small and come from the same lab.
Tinnitus has no objective test. A clinician can measure a patient’s hearing, but the ringing itself exists only in the patient’s report. Two studies from UConn Health, announced by the university on October 6, suggest that a trace of it may show up in a blood sample.
The marker is prestin, a motor protein in the outer hair cells of the cochlea, the cells that amplify incoming vibration and sharpen hearing. In the first study, in Otology & Neurotology, a form of the protein was higher in 49 people with chronic tinnitus than in 40 controls. The second, in Otolaryngology–Head and Neck Surgery, compared 41 people with chronic tinnitus in both ears with 41 controls, each given hearing tests, a week wearing a personal noise dosimeter and a blood draw. Prestin was again higher in the tinnitus group after adjusting for age, hearing thresholds and noise exposure (P = .003). Otoferlin, connexin 26 and stereocilin, three other inner-ear proteins, did not separate the groups.
“Our work now says there is promise in using prestin as a biomarker for tinnitus,” said Kourosh Parham, the UConn Health professor of surgery who is senior author of both papers.
Promise is the right word. New Atlas, which read the second paper, reports that the average gap was 330 picograms per milliliter, that it was not accurate enough to diagnose an individual, that prestin levels did not track how severe a person’s symptoms were, and that most participants had mild tinnitus. Prestin also turns up outside the ear, including in heart tissue. Both studies are small case-control comparisons from one lab, funded by an American Tinnitus Association grant, and Parham’s team says larger ones come next.
