Research report
A research report is the sourced material a domain
dossier is synthesized from — generated on a plan and a cadence, one topic per file.
A report carries no confidence tags. Its bracketed markers say who might have
an incentive to shade a line; none of them says anyone checked it. To reach a score, a line has
to be drafted onto a candidate as unverified and pass the Verifier or the
Corroborator, like everything else.
Section clinical-evidence · Version 2026-09-01 · Cadence quarterly · Evidence class mixed · Sources 11 · Supersedes none
Domain: chronic-subjective-tinnitus-neuromodulation · Scope: Peer-reviewed literature (PubMed/PMID) and ClinicalTrials.gov registry
Sourcing: Rests mostly on single systematic reviews/meta-analyses (2018–2026) that
The 2014 AAO-HNSF guideline is still the only US multidisciplinary tinnitus guideline located, and it names one neuromodulation modality by name — recommending against transcranial magnetic stimulation — while saying nothing about bimodal acoustic-electrical stimulation, a category the FDA did not create until 2023 [1]. Across four independent systematic reviews/meta-analyses of neuromodulation for chronic subjective tinnitus published 2024–2026, pooled rTMS benefit is consistently short-term and fails to persist to six months, and reviews disagree with each other on whether tDCS clears statistical significance at all [2][3][4][5]. Pooled bimodal stimulation (acoustic plus a second modality) is reported by the most recent and most comprehensive of these reviews as the most consistent and durable performer among the modalities it assessed, resting on four trials totaling n=582 [2]. The predicate device's own third confirmatory trial, registered under NCT05227365 with an actual enrollment of 112, remains without posted results as of this report's access date, more than three years after its 2022 registration [9].
_Baseline (v1). No prior version; this establishes the starting point for future diffs._
The AAO-HNSF's 2014 Clinical Practice Guideline: Tinnitus is the only US multidisciplinary guideline located for this domain, and no post-2014 update from that body was found by a dedicated search of PubMed for "American Academy Otolaryngology Head Neck Surgery tinnitus guideline 2024 update" run this pass — recorded as not found, not confirmed absent [1]. The guideline's own fact sheet states its recommendation against one neuromodulation modality by name: "Clinicians should NOT recommend transcranial magnetic stimulation for treating patients with persistent, bothersome tinnitus" [1]. No action statement addressing bimodal acoustic-electrical stimulation, transcutaneous electrical nerve stimulation, transcranial direct current stimulation, or vagus nerve stimulation appears in the executive summary read at abstract depth [1] — those modalities either postdate the guideline commercially (bimodal, per the domain dossier's own account of the 2023 De Novo grant) or were outside its 13 action statements' scope. A German S3 clinical guideline for chronic tinnitus was updated in 2021 and described in a 2024 English-abstract review, but this is a non-US guideline, named here only as an international comparator, since this report's own scope is US [10] [single-source].
The most comprehensive review located, a 2026 systematic review and meta-analysis of 26 randomized controlled trials (n=1,576) spanning transcranial electrical stimulation (11 trials, n=372), rTMS (8 trials, n=432), acoustic coordinated reset (1 trial, n=100), vagus nerve stimulation (2 trials, n=90), and bimodal stimulation (4 trials, n=582), found: "a nonsignificant pooled effect for tDCS (SMD -0.36; 95% CI -0.75 to 0.02)" and for rTMS (SMD -0.15; 95% CI -0.37 to 0.07); a single acoustic-coordinated-reset trial "showed no advantage over broadband noise"; VNS "demonstrated modest benefits with safety concerns limited to implanted approaches"; and bimodal stimulation "yielded consistent, clinically meaningful reductions (often ≥10-20 points on THI/TFI), with durability up to 12 months" [2] [single-source]. This is the newest and largest pooled synthesis found and it has not yet been independently corroborated by a second review of the same scope.
On rTMS specifically, two independent meta-analyses converge: a 16-RCT, n=1,105 Cochrane risk-of-bias-graded review found rTMS "superior to Sham rTMS in THI and VAS" with "a positive effect on the short-term impact of THI (1 month)" but "did not observe a positive effect of rTMS on the long-term implications of tinnitus (6 months)" [3]; a 32-trial, n=1,561 review pooling several non-invasive modalities similarly found benefits "most pronounced immediately post-treatment and at 1-3 months, with effects diminishing by 6 months (MD -3.93, p=0.06)" [4]. This short-term-only pattern for rTMS is therefore stated plainly, resting on ≥2 independent non-affiliated reviews. On tDCS the reviews disagree: an earlier (19-RCT, n=1,186) review found "the short-term effect of ... transcranial direct current stimulation on THI score is -19.0 [-30.1 to -7.8]," reported as significant [5] [single-source], while the two more recent reviews above found tDCS's pooled effect nonsignificant [2][4] [single-source] — the two most recent reviews disagree with the older one on this modality, a genuine disagreement across reviews on the same modality, not a single converging finding.
Before the predicate device's own tongue-electrode configuration reached De Novo (covered in the domain dossier §5), the underlying auditory-somatosensory bimodal mechanism was tested by a different research group using cervical/neck stimulation rather than tongue stimulation: a 2018 guinea-pig-and-human study reported that in a double-blinded, sham-controlled, crossover trial of 20 human subjects, "28 days of LTD-inducing bimodal stimulation reduced tinnitus loudness and intrusiveness. Unimodal auditory stimulation did not deliver either benefit" [6] [single-source]. A separate, smaller configuration — acoustic stimulation paired with transcutaneous auricular vagus nerve stimulation rather than tongue or cervical stimulation — was tested in a 34-participant randomized trial (17 bimodal, 17 sham/unimodal) reporting "a statistically significant decrease in THI scores ... in the bimodal group compared to the unimodal group," stable at one month [7] [single-source]; a companion analysis of what appears to be the same 34-participant cohort (same group sizes, same intervention arms) reported a secondary auditory-sensory-gating outcome, again favoring the bimodal arm, while noting "it may not be effective for all patients" [8] [single-source — likely the same trial as [7], not independent corroboration]. None of these three device configurations is the predicate's own tongue-electrode product; they are cited here to show that bimodal acoustic-plus-somatosensory stimulation as a mechanism has been tested by at least three separate research groups using three different electrode sites, with small samples (n=20 to n=34) in all cases except the predicate's own trials.
The clearest negative finding specific to a named modality remains the guideline's own action statement against TMS [1]. The clearest equivocal finding is rTMS's short-term-only benefit, agreed across two independent reviews [3][4]. The most consequential open negative-or-unknown finding for this domain, though, is procedural rather than a reported effect size: the predicate's own third confirmatory trial, TENT-A3 (NCT05227365), is a single-arm, unmasked, industry-sponsored study with an actual enrollment of 112 adults, registered with status COMPLETED and a stated primary outcome of Tinnitus Handicap Inventory change from enrollment to week 12 — and as of this report's access date it has posted no results [9] [sponsor-reported]. Under this domain's own evidentiary rule, a registered outcome with no results posted is the sponsor's intention, not a finding, whatever its enrollment or completion status says. Separately, a University of Michigan-sponsored randomized, quadruple-masked, crossover trial of an auditory-somatosensory approach (n=100 actual) is recorded on ClinicalTrials.gov as having results posted (hasResults=true), but this report did not retrieve those posted results beyond the registry's protocol-level fields, and no effect size from it is carried forward here as a finding [11] — see Section 5.
[1] Tunkel DE, Bauer CA, Sun GH, et al. "Clinical Practice Guideline: Tinnitus (Executive Summary)" — Otolaryngology–Head and Neck Surgery (published 2014-10-01; accessed 2026-09-01). PMID 25274374 — https://pubmed.ncbi.nlm.nih.gov/25274374/ ; TMS recommendation quote independently confirmed via AAO-HNSF, "AAO-HNSF Clinical Practice Guideline: Tinnitus" fact sheet, https://www.entnet.org/resource/aao-hnsf-cpg-tinnitus-press-release-fact-sheet/ (accessed 2026-09-01) [guideline] [2] "Neuromodulation for Subjective Tinnitus: A Systematic Review and Meta-Analysis of Randomized Trials" — The Laryngoscope (published 2026, month not given in the PubMed record; accessed 2026-09-01). PMID 42167925 — https://pubmed.ncbi.nlm.nih.gov/42167925/ [peer-reviewed] [3] "Efficacy of repetitive transcranial magnetic stimulation for subjective chronic tinnitus: a randomized controlled trial meta-analysis" — Frontiers in Neuroscience (published 2025, month not given in the PubMed record; accessed 2026-09-01). PMID 40303608 — https://pubmed.ncbi.nlm.nih.gov/40303608/ [peer-reviewed] [4] "Efficacy of non-invasive neuromodulation for chronic tinnitus: a systematic review and meta-analysis of randomized controlled trials" — European Archives of Oto-Rhino-Laryngology (published 2026-08-20; accessed 2026-09-01). PMID 42625017 — https://pubmed.ncbi.nlm.nih.gov/42625017/ [peer-reviewed] [5] "Neuromodulation for Treatment of Tinnitus: A Systematic Review and Meta-Analysis" — Otolaryngology–Head and Neck Surgery (published 2024-05-01; accessed 2026-09-01). PMID 38353342 — https://pubmed.ncbi.nlm.nih.gov/38353342/ [peer-reviewed] [6] Marsh MA, et al. "Auditory-somatosensory bimodal stimulation desynchronizes brain circuitry to reduce tinnitus in guinea pigs and humans" — Science Translational Medicine (published 2018-01-03; accessed 2026-09-01). PMID 29298868 — https://pubmed.ncbi.nlm.nih.gov/29298868/ [peer-reviewed] [7] "Effectiveness of bimodal stimulation of the auditory-somatosensory system in the treatment of tonal tinnitus" — American Journal of Otolaryngology (published 2024, Nov-Dec issue, day not given in the PubMed record; accessed 2026-09-01). PMID 39116719 — https://pubmed.ncbi.nlm.nih.gov/39116719/ [peer-reviewed] [8] "Bimodal Stimulation of the Auditory-Somatosensory System Improves Auditory Sensory Gating Function in Patients with Tinnitus" — Journal of the American Academy of Audiology (published 2026, month not given in the PubMed record; accessed 2026-09-01). PMID 42403966 — https://pubmed.ncbi.nlm.nih.gov/42403966/ [peer-reviewed] [9] ClinicalTrials.gov record NCT05227365 — "Treatment Evaluation of Neuromodulation for Tinnitus - Stage A3" (TENT-A3), Neuromod Devices Ltd. (record dated 2022-12-27; status COMPLETED; hasResults=false; accessed 2026-09-01). NCT05227365 — https://clinicaltrials.gov/study/NCT05227365 [trial-registry] [10] "S3-Guideline Chronic Tinnitus – Update" (translated title; a German-language guideline update, non-US) — Laryngo-Rhino-Otologie (published 2024, month not given in the PubMed record; accessed 2026-09-01). PMID 38830358 — https://pubmed.ncbi.nlm.nih.gov/38830358/ [guideline] [11] ClinicalTrials.gov record NCT03621735 — "Reversing Synchronized Brain Circuits With Targeted Auditory-Somatosensory Stimulation to Treat Phantom Percepts," University of Michigan (record dated 2023-08-30; status COMPLETED; hasResults=true; accessed 2026-09-01). NCT03621735 — https://clinicaltrials.gov/study/NCT03621735 [trial-registry]
Well established: The AAO-HNSF guideline's recommendation against TMS, independently confirmed by the peer-reviewed executive summary and the guideline's own fact sheet [1]. The short-term-only pattern of rTMS benefit, agreed across two independent meta-analyses with different search dates and different author teams [3][4].
Thin: Everything else in Section 3 rests on exactly one review or one small trial: the 2026 Laryngoscope review's ranking of bimodal stimulation as the most consistent modality [2]; the disputed tDCS effect size, where three reviews do not agree [2][4][5]; the three small (n=20–34) analogous bimodal configurations outside the predicate [6][7][8], two of which appear to be companion papers on the same cohort rather than independent studies; and the German S3 guideline, cited only as a non-US comparator [10].
Rescoped from class 3: None in this report. Every proposition here is class 1 (a named ClinicalTrials.gov record's status) or class 2 (a measured effect size in a cited review or trial), not a question about what a person would do.
Out of scope: Full-text retrieval of any of the four systematic reviews — all four were read at abstract depth only, so no risk-of-bias table, funding disclosure, or per-trial breakdown behind any pooled estimate was checked. HCPCS/payment/coverage material (already flagged absent at the domain level; not attempted again here — clinical-evidence, not reimbursement, is this report's section). CPT descriptors (AMA-licensed, excluded by standing rule). Non-US guidelines beyond the single German S3 comparator named above.
Not searched vs. not found: A post-2014 AAO-HNS guideline update was searched for this pass (a dedicated PubMed query, distinct from the domain dossier's earlier search) and not found — this is a stronger negative than the dossier's original "not searched to exhaustion" note, though it remains a search-based absence, not a confirmation that AAO-HNS never issued one. The posted results for NCT03621735 were not searched at the outcome-data level — the registry record was retrieved and its hasResults=true flag noted, but the results module itself was not fetched or read this pass, so this is "not retrieved," not "not found." A published full-text report specifically pairing TENT-A2/TENT-A3 dropout data with a stated reason was searched for (as a continuation of the domain dossier's own open question) and not found at abstract depth in this pass either.
[inference] The apparent overlap between [7] and [8] (identical n=34, identical 17/17 group split, identical intervention description) suggests these are two outcome-measure papers from a single underlying trial rather than two independent replications; this is my own reading of the two abstracts side by side, not a fact stated in either record, and it is why Section 3 marks [8] as non-independent of [7] rather than as separate corroboration.
| Proposition | Evidence class | Resolvable identifier | Dossier section |
|---|---|---|---|
| The AAO-HNSF 2014 guideline states clinicians should not recommend transcranial magnetic stimulation for persistent, bothersome tinnitus | 2 — published finding | PMID 25274374 | 4. Standard of care & clinical evidence |
| A 2026 meta-analysis of 26 RCTs (n=1,576) found pooled rTMS effect nonsignificant (SMD -0.15; 95% CI -0.37 to 0.07) while bimodal stimulation (4 trials, n=582) showed reductions of often ≥10-20 THI/TFI points with durability up to 12 months | 2 — published finding | PMID 42167925 | 4. Standard of care & clinical evidence |
| Two independent meta-analyses (16 RCTs/n=1,105; 32 RCTs/n=1,561) found rTMS benefit present at 1-3 months but not sustained at 6 months | 2 — published finding | PMID 40303608; PMID 42625017 | 4. Standard of care & clinical evidence |
| ClinicalTrials.gov record NCT05227365 (TENT-A3, Neuromod Devices Ltd., actual enrollment 112) is status COMPLETED with no results posted as of 2026-09-01 | 1 — registry fact | NCT05227365 | 5. Reference products |
| A 2018 double-blind, sham-controlled, crossover trial (n=20) of cervical-site auditory-somatosensory bimodal stimulation reduced tinnitus loudness and intrusiveness versus unimodal stimulation | 2 — published finding | PMID 29298868 | 5. Reference products |