Summary: Researchers have discovered objective biomarkers for tinnitus by measuring pupil dilation and subtle, involuntary facial movements that reflect levels of distress. Using AI-driven video analysis, the team found that people with severe tinnitus exhibit persistently enlarged pupils and diminished facial reactions to sounds—signs of chronic vigilance and heightened autonomic arousal.
These measurable signals mark a major advance for a condition long assessed primarily through subjective questionnaires. The results could enable accessible diagnostic tools, strengthen clinical trial endpoints, and guide development of targeted treatments for tinnitus and related sound-sensitivity disorders.
Key Facts:
- Objective biomarkers: Pupil dilation and involuntary facial movements reliably predict tinnitus distress.
- AI-assisted detection: Machine analysis of video reveals tiny facial twitches linked to suffering.
- Clinical potential: These measures could improve diagnosis, therapy evaluation, and trial design.
Source: Mass General Brigham
Overview: Researchers at Mass General Brigham have identified measurable autonomic and behavioral signatures of tinnitus by tracking pupils and minute facial movements that correspond with patients’ reported distress.
Published in Science Translational Medicine, the study addresses a key barrier in tinnitus research—the lack of objective measures—which has historically limited placebo-controlled trials and the development of evidence-based therapies.
“Imagine if cancer severity were gauged only by a questionnaire—yet that is how many neurological conditions, including tinnitus, are currently evaluated,” said Daniel Polley, PhD, vice chair for basic science research and director of the Eaton-Peabody Laboratories at Mass Eye and Ear (Mass General Brigham). “For the first time, we observed a clear physiological signature of tinnitus severity. It was surprising to find that involuntary facial motions not only occur in response to sound but also serve as one of the most informative predictors of tinnitus-related distress.”
Tinnitus causes persistent phantom sounds—ringing, buzzing, or clicking—and affects roughly 12% of the general population and about 25% of people aged 65 and older. While many regard it as an annoyance, an estimated 15% of those with tinnitus experience severe symptoms that impair sleep, mood, and daily functioning. Until now, clinicians lacked objective tools to distinguish mild from debilitating cases.
Beyond conventional hearing tests and measures of central auditory function, Polley’s team examined downstream autonomic responses—markers of the sympathetic “fight, flight, or freeze” system—hoping to reveal outward, involuntary signs of distress that might otherwise go unnoticed.
Guided by prior knowledge that pupil dilation reflects emotional arousal and that facial micro-movements can indicate threat assessment, the researchers hypothesized that people with disabling tinnitus exist in a heightened vigilance state, reacting to everyday sounds like potential threats.
To test this idea, 97 adults with normal hearing were recruited: 47 participants with varying tinnitus and sound-sensitivity symptoms and 50 healthy control volunteers. While listening to a range of sounds—pleasant, neutral, and aversive (for example, coughing fits, shouting, or a baby crying)—participants were video-recorded and their pupils tracked.
AI-powered software analyzed the recordings to detect very small, rapid facial movements—twitches of the cheeks, brows, or nostrils—that correlated with patients’ reported tinnitus distress. When these facial metrics were combined with pupil-dilation data, the ability to predict individual tinnitus severity scores improved substantially.
Key patterns emerged: individuals with severe tinnitus showed consistently enlarged pupils across all sound types, while their facial responses to the same sounds were muted. By contrast, participants without tinnitus or with less troubling tinnitus displayed pronounced pupil dilation and facial movement primarily in response to the most unpleasant sounds.
These objective measures also related to questionnaire scores for hyperacusis (reduced tolerance for everyday sounds), though they more accurately predicted tinnitus severity than hyperacusis.
“A major strength of this approach is that it does not rely on expensive brain scanners,” said Polley, who also directs the Lauer Tinnitus Research Center at Mass Eye and Ear. “If adapted to consumer-grade devices, these biomarkers could be used in audiology clinics, incorporated into clinical trials as objective endpoints, and made available to the public for self-assessment.”
The authors note an important limitation: the study excluded many people with co-occurring conditions such as hearing loss, older age, or psychiatric comorbidities in order to demonstrate the method’s feasibility. Future work will expand to include those higher-risk groups and test the approach in more diverse clinical populations.
Polley’s lab is already using these biomarkers to guide novel interventions that pair neural stimulation with immersive software environments intended to reduce or eliminate the perceived loudness of tinnitus. “These biomarkers target the core of the distress,” he added. “While brain imaging can reveal hyperactive auditory regions, pupil and facial signals reveal body-wide threat-evaluation systems operating outside their normal range and driving the troubling symptoms patients experience.”
Authorship: Additional Mass General Brigham contributors include Samuel S. Smith, Kelly N. Jahn, Jenna A. Sugai, and Ken E. Hancock from the Eaton-Peabody Laboratories at Mass Eye and Ear.
Disclosures: Polley serves on advisory boards for the American Tinnitus Association, Hyperacusis Research Ltd, and Tinnitus Quest. Kelly N. Jahn is a member of advisory boards for Hyperacusis Research Ltd and Hyperacusis Central.
Funding: This work was supported by grants from the National Institute on Deafness and Other Communication Disorders (P50DC015857 and K01DC019647) and an ASHFoundation New Investigators Research Grant.
About this research news
Author: Ryan Jaslow
Source: Mass General Brigham
Contact: Ryan Jaslow – Mass General Brigham
Image credit: Neuroscience News
Original research: Closed access. Title: “Objective Autonomic Signatures of Tinnitus and Sound Sensitivity Disorders,” by Daniel Polley et al., published in Science Translational Medicine.
Abstract
Objective Autonomic Signatures of Tinnitus and Sound Sensitivity Disorders
Hypersensitivity, phantom percepts, and exaggerated sensory reactivity are core features of many neurological conditions. Objective, direct measures of these phenomena have been difficult to identify, leaving clinicians to rely primarily on subjective questionnaires. In this study, neurotypical adults (n = 50) and adults with tinnitus and sound sensitivity (n = 47) were evaluated to identify reproducible objective markers linked to symptom severity.
Central auditory gain measures were elevated in participants with tinnitus and sound sensitivity but did not correlate with how severe patients reported their symptoms. Instead, pupil dilations and involuntary facial movements elicited by emotionally charged sounds accurately predicted individual scores on the Tinnitus Handicap Inventory (THI) and the Hyperacusis Questionnaire (HQ).
These results reveal autonomic signatures of disrupted affective sound processing in tinnitus and sound-sensitivity disorders and introduce promising, objective approaches for their assessment and monitoring.