A new study published in Science Translational Medicine has identified involuntary facial and eye responses that may serve as objective biomarkers of tinnitus-related distress. The findings, from researchers at Mass General Brigham, mark a potential breakthrough for advancing diagnostics and evaluating treatments for tinnitus, a condition that affects millions of people worldwide.
The team, led by Dr. Daniel Polley of Mass Eye and Ear, recorded pupil dilation and subtle facial movements as participants listened to various pleasant and unpleasant sounds. They found that these automatic responses closely correlated with self-reported levels of tinnitus severity—suggesting an outward physiological signature for an otherwise subjective condition.
“Imagine if cancer severity were determined by giving patients a questionnaire—this is the state of affairs for some common neurological disorders like tinnitus,” said Polley, vice chair for basic science research and director of the Eaton-Peabody Laboratories at Mass Eye and Ear. “For the first time, we directly observed a signature of tinnitus severity.”
Tracking the Body’s Threat Response
A close-up view illustrates the tracking of a study participant’s pupil and face. Credit: Mass Eye and Ear
Tinnitus, which commonly presents as a persistent ringing, buzzing, or clicking sound, affects an estimated 12% of the general population and up to 25% of individuals over the age of 65. While many consider it a minor nuisance, approximately 15% report significant impairment in sleep, mental health, and daily functioning.
The study explored how tinnitus distress may be tied to the body’s sympathetic nervous system—or “fight, flight, or freeze” response. The researchers hypothesized that individuals with more severe tinnitus exist in a chronic state of vigilance, reacting to everyday sounds as if they were threats.
To test this, they recorded videos of 97 participants—47 with tinnitus and 50 healthy controls—as they listened to a range of sound types. Using AI-powered software, the team detected rapid, involuntary facial twitches and measured pupil responses. The results revealed that:
- Participants with severe tinnitus had consistently wide pupil dilation across all sounds and blunted facial reactions, even to distressing stimuli.
- By contrast, individuals with mild or no tinnitus showed more differentiated reactions, with strong responses only to unpleasant sounds.
“When we began this study, we didn’t know if sounds would elicit facial movements; so, to discover that these movements not only occur, but can provide the most informative measure to date of tinnitus distress, is quite surprising,” Polley said.
The approach also predicted participants’ hyperacusis (sound sensitivity) scores, though less precisely than for tinnitus severity.
“What’s really exciting is this vantage point into tinnitus severity didn’t require highly specialized brain scanners; instead, the approach was relatively low-tech. If we can adapt this approach to consumer-grade electronics, they could be put to use in hearing health clinics, as objective measures in clinical trials and by the public at large.”
–Dr. Daniel Polley
This graph shows larger sound-evoked pupil dilations but attenuated facial movements in participants with tinnitus/sound sensitivity. Credit – Mass Eye and Ear
The study excluded individuals with more complex profiles—such as those with hearing loss, older age, or mental health conditions—in order to isolate the predictive value of the measured responses. The authors note that future research will aim to include these higher-risk populations.
Looking ahead, Polley’s team is applying the identified biomarkers to the development of therapies that pair neural stimulation with immersive software environments to reduce or eliminate the tinnitus percept.
“These biomarkers get to the root of the distress,” Polley explained. “While imaging might show hyperactive brain regions in tinnitus patients, these biomarkers reveal body-wide threat evaluation systems that are operating outside of their normal range, leading to the distressful symptoms they experience.”
Citation:
Smith, S. S., Jahn, K. N., Sugai, J. A., Hancock, K. E., & Polley, D. B. (2025). Objective autonomic signatures of tinnitus and sound sensitivity disorders. Science Translational Medicine. https://doi.org/10.1126/scitranslmed.adp1934
Source: Mass Eye & Ear, STM
