Somatosensory Tinnitus: Botulinum Toxin Treatment Review

A scoping review has identified a plausible anatomical and neurophysiological link between hyperactivity in the jaw’s masseter muscle and a subtype of tinnitus. The review, which screened 284 records, concluded that while Botulinum Toxin Type A (BoNT/A) is a logical hypothesis for treatment, direct clinical evidence for its use remains insufficient and requires controlled trials.

## The Somatosensory Tinnitus Subtype: A Muscle-Ear Connection

The persistent perception of sound in the absence of an external source defines tinnitus. For many, this is linked to hearing loss. For a distinct group, however, the trigger may lie not in the ear but in the muscles and joints of the head and neck. This is the somatosensory subtype of tinnitus. Here, inputs from craniocervical and craniomandibular structures—like the jaw, neck muscles, and temporomandibular joint (TMJ)—can modulate the tinnitus signal within the brain’s central auditory pathways. Think of it as a cross-wiring issue: heightened activity in the jaw can inadvertently turn up the volume on the brain’s internal noise generator. This connection explains why some people can change their tinnitus by clenching their jaw or moving their neck.

## Scoping Review Methodology: A Search for Direct Evidence

To investigate the specific link between masseter muscle activity and tinnitus, and to assess the therapeutic rationale for BoNT/A, authors Jacopo Gardellin, Marta D’Angelo, and Lorenzo Spadotto conducted a structured scoping review. They followed PRISMA-ScR guidelines, searching two major biomedical databases, MEDLINE and EMBASE, with three complementary search strategies. The final search was run on 31 May 2026. Their goal was not to perform a meta-analysis but to map the available evidence and identify gaps in knowledge. From an initial 284 records screened, the process was exacting. Only four studies met the strict eligibility criteria. Three came from a search on BoNT/A and tinnitus, and one from a search on tinnitus and masticatory (chewing) dysfunction. The authors also identified one additional relevant record (Ranoux and Levine, 2024) through a manual search of the literature.

## Limited but Promising Findings on Botulinum Toxin

The findings illustrate a field with more theory than conclusive data. The included studies collectively build an anatomical and neurophysiological case. They support the idea that hyperactivity in the masseter muscle—a primary muscle for chewing—can generate abnormal somatosensory signals. These signals may then converge with auditory processing in the brainstem, potentially sustaining or exacerbating tinnitus perception.

The manually identified record by Ranoux and Levine (2024) provides a direct, though preliminary, clinical observation. It describes a protocol where patients received BoNT/A injections in the periauricular (around the ear) and splenius capitis (a neck muscle) regions, with reported improvement in tinnitus. Notably, the same protocol proposes the masseter and temporalis (temple) muscles as alternative injection sites, directly linking jaw muscle modulation to potential auditory benefit. This aligns with existing clinical use; BoNT/A is a well-established treatment for conditions involving masseter hyperactivity, such as bruxism (teeth grinding) and TMJ disorders. You can read a detailed analysis of this muscle-based approach in our article, Botulinum Toxin for Tinnitus: Masseter Muscle Review.

## Practical Implications: A Cautious, Multidisciplinary Path Forward

The authors’ conclusions are measured. They state that BoNT/A may theoretically reduce the abnormal somatosensory input believed to drive this tinnitus subtype. However, they emphasize that direct clinical evidence for tinnitus improvement is still insufficient. Therefore, they classify the use of BoNT/A for somatosensory tinnitus as **experimental or hypothesis-based**.

For patients and clinicians, this has clear implications. First, it reinforces the importance of a multidisciplinary assessment. Someone with tinnitus should be evaluated not just by an audiologist, but potentially by a dentist specializing in TMJ disorders or a physical therapist focusing on the cervical spine. Identifying a somatic component—like jaw pain, teeth grinding, or a history of neck injury—is a critical first step. The link between such issues and auditory symptoms is further explored in our piece on Migraine Links to Hearing Disorders and Tinnitus, as these conditions often co-occur.

Second, if BoNT/A is considered, it should be part of a broader management plan. The authors insist it must be administered within a multidisciplinary framework and paired with standardized outcome assessments to track its effect. This is not a standalone “cure” but a potential component of a tailored treatment strategy that could include sound therapy, which we review in Best Tinnitus Sound Machine Review: Evidence-Based 2026 Study.

## The Clear Need for Prospective Controlled Trials

The most urgent call from this review is for more robust research. The scant number of qualifying studies—effectively five—highlights a significant evidence gap. The authors explicitly state that prospective, controlled clinical trials are necessary. These trials need to clearly define the somatosensory tinnitus patient population, use precise injection protocols (like those targeting the masseter), and measure outcomes with validated tinnitus questionnaires and functional assessments.

Until such data is available, the connection between masseter muscle and tinnitus remains a compelling scientific hypothesis with cautious clinical potential. It offers a new direction for understanding a complex condition, moving beyond the ear to consider the integrated system of the head and neck.

**Source:** Gardellin, J.; D’Angelo, M.; Spadotto, L. Anatomical and Neurophysiological Rationale for Botulinum Toxin Type A in Somatosensory Tinnitus Secondary to Masseter Hyperactivity: A Scoping Review. *Toxins* 2026, *18*, 310. https://doi.org/10.3390/toxins18070310