Bimodal stimulation (Lenire): the tongue-and-sound device explained

Lenire is a prescription medical device that treats chronic subjective tinnitus using bimodal neuromodulation, a combination of sounds delivered through wireless earbuds and mild electrical pulses delivered to the surface of the tongue through a mouthpiece called the Tonguetip. The FDA authorized Lenire in May 2023 under the De Novo pathway, making it the first bimodal neuromodulation device approved for tinnitus management in the United States. Developed by the Irish company Neuromod Devices, Lenire had already been available in Europe under CE marking since 2019.

The biological rationale

The scientific basis for bimodal stimulation comes from neuroscience research into the dorsal cochlear nucleus (DCN), a structure in the brainstem where auditory signals are first processed at a central level. Animal models of tinnitus show abnormal spontaneous firing and hypersynchrony in DCN neurons after cochlear damage. Critically, the DCN also receives inputs from somatosensory pathways, including those carrying signals from the face, jaw, neck, and tongue via the trigeminal nerve.

This convergence of auditory and somatosensory information in the DCN creates a target for neuromodulation. The hypothesis is that pairing sound with somatosensory stimulation in the correct timing relationship can drive Hebbian plasticity, the principle that neurons that fire together wire together. By repeatedly presenting auditory tones and tongue stimulation simultaneously, the aim is to reduce the maladaptive hyperactivity in the DCN that underlies the tinnitus percept.

The tongue is used as the delivery site for somatosensory stimulation because it has dense sensory innervation and a well-established afferent pathway to the brainstem. The Tonguetip mouthpiece uses an array of small electrodes to deliver mild electrical pulses, which users typically describe as a mild tingling or fizzing sensation.

How the device is used

Lenire is a prescription device available only through trained clinicians, typically audiologists or otolaryngologists who have completed Neuromod’s certification program. The fitting process involves assessing the patient’s tinnitus characteristics and hearing profile, programming the acoustic component to match the patient’s tinnitus frequency range, and setting the tongue stimulation level to the patient’s comfort threshold.

The treatment protocol studied in clinical trials involved daily 60-minute sessions, with users free to listen and wear the Tonguetip during the session. Sessions can be divided across the day. The clinical trial protocol ran for 12 weeks, though some patients continue treatment beyond this period.

Evidence from clinical trials

The TENT-A1 and TENT-A2 trials, conducted by Neuromod and published in peer-reviewed journals, form the primary clinical evidence base. TENT-A1 was a blinded crossover trial comparing bimodal stimulation against two control conditions: auditory-only stimulation and somatosensory-only stimulation. TENT-A2 extended the study with a 12-month follow-up.

TENT-A1 results showed that bimodal stimulation produced statistically greater reductions in Tinnitus Handicap Inventory (THI) scores and Tinnitus Functional Index (TFI) scores compared to the control arms. Over 80% of participants who completed the bimodal treatment arm showed clinically meaningful reductions in at least one of the two primary outcome measures.

TENT-A2 follow-up data suggested that benefits were maintained at 12 months in a substantial proportion of participants, with some showing further improvement between the 12-week treatment endpoint and the 12-month follow-up. This durability signal is clinically relevant because many tinnitus interventions show rapid post-treatment regression.

Independent researchers have noted that the trial design, while rigorous by tinnitus trial standards, has limitations common to the field: the blinding of participants to which condition they were in is imperfect because bimodal stimulation has a subjectively distinct quality from either component alone, and the trials were sponsored by the device manufacturer.

Who the device is intended for

The FDA clearance specifies that Lenire is for adults 18 and older with chronic subjective tinnitus lasting at least six months. The audiological eligibility criteria require that the patient’s hearing profile falls within a specified range, since the acoustic component is customized to the patient’s hearing. Patients with very severe hearing loss may not meet the audiological criteria.

Contraindications include the presence of an active implanted electrical device (such as a cochlear implant or pacemaker), certain oral health conditions that preclude comfortable use of the Tonguetip, and some neurological conditions. A thorough clinical assessment by a trained Lenire provider is required before prescribing.

Realistic expectations

Clinical trial data show that a meaningful proportion of patients with chronic tinnitus experience reduced distress and improved quality of life with Lenire, but results are not uniform. Some patients show little or no benefit, and complete elimination of the tinnitus sound has not been reported as a reliable outcome. The device addresses tinnitus distress and handicap rather than the acoustic perception itself.

The device is one of several tinnitus management options rather than a cure. Cognitive behavioral therapy remains the intervention with the most robust evidence for reducing tinnitus distress, and many patients benefit from combining approaches. Lenire may be particularly suitable for patients who have not responded adequately to sound therapy and counseling-based approaches, or who prefer a structured neuromodulation protocol.

Access and cost

Lenire is available in the United States through certified providers. As a relatively new device with limited insurance coverage, the out-of-pocket cost is a significant access barrier for many patients. Clinicians certified to fit the device can be located through the Neuromod website, and some academic audiology centers have begun incorporating it into their tinnitus programs.

For patients considering Lenire, a conversation with an audiologist or ENT who has experience with the device is the appropriate first step. Realistic expectations, a full audiological evaluation, and an understanding of the time commitment involved (60 minutes daily for 12 weeks) help ensure that patients who proceed with treatment are well prepared.

If symptoms persist or change, see an audiologist or physician.