Audio Brainwave Treatment Restores Chronic ACL–PCL Ruptures: MRI-Verified Case Report

Audio Brainwave Treatment Restores Chronic ACL–PCL Ruptures: MRI-Verified Case Report | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Audio Brainwave Treatment Restores Chronic ACL–PCL Ruptures: MRI-Verified Case Report Ugur Dogan, Tahreem Fatima, Umar Hassan This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6831237/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background: Chronic combined anterior- and posterior-cruciate-ligament (ACL/PCL) ruptures typically require graft reconstruction and 6–9 months of rehabilitation, yet many patients fail to regain full functional capacity. Deep Brain Sound Stimulation (DBSS) is a non-invasive audio neuromodulation platform that can entrain selected brain circuits; in this prototype protocol, DBSS targeted the subventricular zone (SVZ) to enhance reparative signalling toward the knee. Case: A 35-year-old man sustained right-knee ACL and PCL tears in 2017. Daily pain rated 6/10 on the Numeric Rating Scale (NRS) persisted despite conservative care. Intervention: Two proprietary DBSS audio sessions (25 min each; monaural/isochronic tones selected from the 100–260 Hz range) were used once daily for 21 days to deliver SVZ-targeted stimulation of the knee. Audio files are freely downloadable for non-profit replication; exact frequency parameters remain confidential. Results: Pain resolved to 0/10 within 48 hours and has remained absent since. MRI at follow-up showed fully intact ACL and PCL fibres with no residual tear or surgical intervention. Conclusions: DBSS-mediated SVZ activation was associated with rapid, durable, MRI-verified healing of chronic dual-cruciate ruptures. A low-cost, home-based audio intervention may benefit a broad population—from competitive athletes to older adults—if confirmed in controlled trials with serial MRI, laxity testing, and biomarker profiling. Cell & Tissue Engineering Stem Cell & Developmental Cell Biology Sports Medicine and Kinesiology Orthopedics Orthopedic Surgery Neurology Biomedical Engineering Renewable Resources Cellular Metabolism Evolutionary Developmental Biology Biotechnology and Bioengineering Cell Communication and Signaling Cellular & Molecular Neuroscience Developmental Neuroscience Rheumatology anterior cruciate ligament posterior cruciate ligament subventricular zone deep brain sound stimulation audio neuromodulation regenerative medicine non-invasive treatment Figures Figure 1 Figure 2 Figure 3 1. Introduction ACL reconstruction is common, yet only about 60–70% of patients regain their pre-injury sport performance and secondary ligament failure remains a concern [ 1 – 3 ]. Combined ACL–PCL injuries impose greater surgical complexity and longer rehabilitation, with staged or single-stage reconstructions often requiring ≥ 6 months before high-pivot activities can be resumed [ 4 ]. Surgical morbidity, prolonged work absence, and incomplete return to sport have therefore driven interest in biologic or regenerative alternatives. Deep Brain Sound Stimulation (DBSS) is a non-invasive auditory neuromodulation method that employs precisely tuned monaural and isochronic tones to elicit frequency-following responses in targeted brain circuits. Since its inception in 2014, over 100 DBSS protocols have been developed and released as part of an ongoing research and development initiative. These applications span a wide range of use cases—including psychiatric, neurological, pain management, sleep regulation, and physical rehabilitation—with user feedback consistently indicating satisfaction rates above 97% [ 5 ]. Though not formally established as clinical treatments, DBSS protocols are informed by existing scientific literature and are iteratively refined based on user-reported outcomes. In one published case, DBSS influenced periventricular activity and coincided with MRI-documented shrinkage of a porencephalic cyst alongside motor function improvement [ 6 ]. The subventricular zone (SVZ) is the principal neural stem cell niche in the adult brain. Although direct evidence of SVZ-derived cells repairing peripheral tissues is lacking, recent work has identified SVZ-like progenitors in peripheral organs and shown that Pigment Epithelium-Derived Factor (PEDF)-derived neurotrophic peptides accelerate tendon healing [ 7 , 8 ]. Together these findings suggest that activating the SVZ could trigger reparative signaling beyond the CNS. We therefore hypothesize that SVZ stimulation may promote regeneration of damaged knee ligaments. We report a rare case—confirmed by serial MRI—of complete radiological and functional healing of chronic ACL and PCL tears after a three-week DBSS program. 2. Patient Information A 35-year-old physically active man injured his right knee while playing recreational soccer in December 2017. He declined graft surgery for family and prior-surgery reasons. Prior management (2017–2024) The patient intermittently used oral non-steroidal anti-inflammatory drugs (NSAIDs) and topical counter-irritant creams, with limited relief. A self-guided weight-loss effort in 2018 led to ~ 5 kg reduction and modest symptom improvement. No structured physiotherapy, bracing, or intra-articular therapies were undertaken. Throughout this period, he experienced daily knee aching rated 6/10 on the 11-point NRS, especially during walking, running, and squatting. In October 2024, he consulted the senior author (a relative) and consented to a trial of a knee-targeted DBSS protocol designed to activate SVZ stem-cell activity. 3. Clinical Timeline Date Event & findings 20 Dec 2017 MRI #1 (1.5 T): complete ACL tear, high-grade PCL tear. 2017–2024 NSAIDs, creams, ~ 5 kg weight loss; pain stable NRS 6. 15 Oct 2024 DBSS started: two 25-min sessions once daily. 17 Oct 2024 Pain 0/10 at rest and during normal activity. 5 Nov 2024 Course completed (20/21 days; 99% adherence, no adverse effects). 6–19 Nov 2024 Listened again for reassurance; pain remained 0/10. 20 Nov 2024–14 May 2025 No further DBSS or treatment; remains pain-free and fully active. 2 May 2025 MRI #2 (1.5 T): continuous ACL & PCL, no effusion; DICOM dataset—see Data-Availability. 4. Therapeutic Intervention Item Details Delivery Format Two FLAC audio files (Vital Tones), played with standard over-ear headphones. Protocol Multi-segment knee program: both 25-min sessions sequentially stimulate SVZ sub-regions mapped to the full knee joint. Signal characteristics Multi-frequency monaural & isochronic tones, selected from the 100–260 Hz range, engineered to entrain SVZ activity and bias reparative signalling to the knee [ 5 ]. Equipment Over-ear consumer headphones (20 Hz–20 kHz); bilateral listening (both ears) was used in this case. Dosage Both sessions once daily × 21 days. Adherence 99%; no adverse effects. Availability Audio files (non-profit research use) and DICOM dataset—see Data-Availability Future recommendation A four-week schedule is suggested for prospective studies to accommodate larger or more complex tears 5. Outcomes (October 2024 – May 2025) 5.1 Symptom course ● Pain: Baseline NRS 6/10 → 0/10 within 48 h; 0/10 maintained through 14 May 2025. ● Adverse effects: None reported during or after the 21-day intervention, including the brief reassurance-listening period (6–19 Nov 2024). 5.2 Functional status ● By day 2, the patient resumed all routine daily and occupational activities—including walking rounds, stair use, squatting, and household tasks—without discomfort or instability. ● He has maintained unrestricted activity for seven consecutive months and gained approximately 5–6 kg without recurrence of pain. ● No formal sport-specific testing was performed, but the patient reports that every movement attempted has remained pain-free. 5.3 Imaging findings Parameter MRI #1 (20 Dec 2017, 1.5 T) MRI #2 (2 May 2025, 1.5 T) ACL Complete tear with fibre discontinuity Continuous ligament of normal calibre and orientation PCL High-grade tear Continuous ligament of normal calibre and orientation Surgical artefact None None Radiologist impression (May 2025): “Anterior and posterior cruciate ligaments are intact; no evidence of prior reconstruction.” Representative sagittal and coronal slices are shown in Figure 1–3 . Complete pre- and post-treatment DICOM datasets are available for independent review (see Data-Availability). 5.4 Patient perspective “Two days after starting the sound sessions, the pain was gone. Since then I’ve walked, worked, and played with my family without thinking about my knee. It feels completely normal.” 5.5 Summary DBSS was associated with rapid pain relief and MRI-verified continuity of both cruciate ligaments, without any adjunct treatment. 6. Discussion Principal findings A patient with MRI-verified combined ACL and PCL tears lived with daily pain for seven years. Within 48 hours of beginning a three-week DBSS program, the pain disappeared, and five-month follow-up MRI showed continuous cruciate-ligament fibres without surgical intervention. Because adult full-thickness ACL ruptures seldom regain anatomical continuity after conservative care, and combined ACL–PCL injuries heal even less frequently without reconstruction [ 9 , 10 ], the recovery observed here is unlikely to be spontaneous. Putative mechanism DBSS delivers monaural/isochronic tones designed to entrain the SVZ. Recent work shows that SVZ neural stem cells secrete systemic growth factors and can even enhance peripheral nerve repair when transplanted outside the CNS [ 7 , 11 ]. We therefore propose that DBSS up-regulates this circulating trophic output and directs it to the knee, accelerating collagen remodelling until structural integrity is restored. Because the two 25-min sessions sequentially map the whole knee capsule—not just the cruciate bundle—any concomitant collateral-ligament or meniscal defects should theoretically receive the same reparative cue. Serial MRI in future trials can determine how soon fibre continuity appears relative to the early analgesic effect. Clinical relevance Universal applicability. A non-invasive, home-based audio protocol may benefit any patient with cruciate-ligament rupture—not only athletes seeking rapid return but also older adults whose degenerated ligaments might be strengthened before failure. Cost and convenience. A one-off € €20 000 when multiple ligaments are repaired, and staged ACL–PCL surgery can exceed €28 000 [ 12 , 13 ]. Supervised rehabilitation alone commonly adds a further €1 500–€3 500 in therapy charges [ 14 ]. Limitations Single-case design without instrumented laxity testing or blinded assessment. Placebo or expectancy effects cannot be excluded, although durable MRI normalisation supports a biological mechanism. Audio parameters remain proprietary; replication files omit exact frequency values and modulation details. The mechanistic link between SVZ entrainment and ligament healing is still speculative; future human studies should combine serial MRI with circulating growth-factor or exosome profiling to confirm the regenerative pathway. Future directions Prospective, controlled studies should: Obtain MRI at multiple time points (e.g., 2, 4, 8 weeks) to map healing kinetics. Include quantitative laxity and functional tests. Optimise protocol parameters—session duration, total weeks, and bilateral vs knee-specific unilateral listening—to identify the fastest effective schedule. Evaluate other ligament and tendon injuries (rotator cuff, Achilles, ulnar collateral ligament) to test the generalisability of DBSS. Colleagues who use the freely available protocol are invited to share de-identified pre- and post-treatment MRI datasets with the author for inclusion in a pooled follow-up report. 7. Conclusion This case documents complete, MRI-verified healing of chronic ACL and PCL ruptures after a three-week course of Deep Brain Sound Stimulation. Pain ceased within 48 h and has not recurred in seven months of unrestricted daily activity. The finding supports the hypothesis that SVZ-targeted neuromodulation may facilitate clinically meaningful, extra-neural tissue repair. Well-designed prospective trials—combining serial imaging, quantitative laxity testing, and blood-borne biomarker analysis—are now justified to confirm efficacy, define healing kinetics, and explore application to other ligaments and tendons. Declarations Data-Availability Statement ● Imaging: Anonymized pre- and post-treatment DICOM MRI files are available upon reasonable request. Please contact the corresponding author via email ( [email protected] ) for access instructions. ● Audio protocol: The two 25-minute DBSS audio sessions, manual, and streaming access are released for non-commercial research use via online registration (secure Google Form): https://forms.gle/YC35TgH6f7LJhSDu7 ● Case contribution: Registered users receive an encrypted upload link (HIPAA/GDPR compliant) to share de-identified pre/post MRI ZIPs and brief clinical notes. ≥3 complete cases qualify for group authorship in pooled follow-up studies; single cases earn formal acknowledgment or a certificate. ● Additional materials: Related publications are available upon request. Funding : No external funding was received for this study. Conflicts of Interest : Uğur Doğan is the founder and chief technology officer of Vital Tones, developer of the DBSS audio protocols. No other financial or non-financial conflicts are declared. Ethics Approval : Institutional review board approval was waived in accordance with institutional policy for single-patient case reports. Patient Consent : Written informed consent was obtained for publication of this case and associated anonymized MRI DICOM files. Acknowledgments : The author thanks the patient for his cooperation and permission to share his experience. References Randsborg, P-H., Cepeda, N., Adamec, D., Rodeo, S. A., Ranawat, A., & Pearle, A. D. (2022). Patient-reported outcome, return to sport, and revision rates 7–9 years after anterior cruciate ligament reconstruction: Results from a cohort of 2042 patients. American Journal of Sports Medicine, 50 (2), 423–432. https://doi.org/10.1177/03635465211060333 Wiggins, A. J., Grandhi, R. K., Schneider, D. K., Stanfield, D., Webster, K. E., & Myer, G. D. (2016). Risk of secondary injury in younger athletes after anterior cruciate ligament reconstruction: A systematic review and meta-analysis. American Journal of Sports Medicine, 44 (7), 1861–1876. https://doi.org/10.1177/0363546515621554 Schwery, N. A., Kiely, M. T., Larson, C. M., Wulf, C. A., Heikes, C. S., Hess, R. W., et al. (2022). Quadriceps strength following anterior cruciate ligament reconstruction: Normative values based on sex, graft type and meniscal status at 3, 6 & 9 months. International Journal of Sports Physical Therapy, 17 (3), 434–444. https://doi.org/10.26603/001c.32378 Fanelli, G. C., & Edson, C. J. (2020). Combined ACL-PCL-medial and lateral side injuries (global laxity). Sports Medicine and Arthroscopy Review, 28 (3), 100–109. https://doi.org/10.1097/JSA.0000000000000276 Doğan, U. (2025). Precision auditory stimulation using Deep Brain Sound technology for neurological and psychiatric conditions: Large-scale observational study [Preprint, Zenodo]. https://doi.org/10.5281/zenodo.15449609 Doğan, U., & Tahreem, F. (2023). Reduction of porencephalic cyst along with the revival of motor control using the Deep Brain Sound Stimulation (DBSS) technology as a novel approach. Biomedical Science and Clinical Research, 2 (1), 144–148. https://doi.org/10.33140/BSCR.02.01.11 Xu, W., Wang, J., Li, P., Zhang, Y., Chen, H., & Zhou, Q. (2025). Multipotent neural stem cells originating from neuroepithelium exist outside the mouse central nervous system. Nature Cell Biology, 27 (5), 605–618. https://doi.org/10.1038/s41556-025-01641-w Ho, T. C., Chau, Y. P., Liu, H. L., Chen, L. J., Chiu, S. J., & Chang, S. Y. (2019). PEDF-derived peptide promotes tendon regeneration through its mitogenic effect on tendon stem/progenitor cells. Stem Cell Research & Therapy, 10 , Article 2. https://doi.org/10.1186/s13287-018-1110-z Blanke, F., Trinnes, K., Oehler, N., Prall, W. C., Lutter, C., Tischer, T., & Vogt, S. (2023). Spontaneous healing of acute ACL ruptures: Rate, prognostic factors and short-term outcome . Archives of Orthopaedic and Trauma Surgery, 143 (7), 4291–4298. https://doi.org/10.1007/s00402-022-04701-0 Suneja, A., Deshpande, S. V., Wamborikar, H., Date, S. V., Goel, S., & Sekhon, G. (2023). Outcome analysis of posterior cruciate ligament injuries: A narrative review. Cureus, 15 (10), e47410. https://doi.org/10.7759/cureus.47410 Bhangra, K. S., Busuttil, F., Phillips, J. B., & Rahim, A. A. (2016). Using stem cells to grow artificial tissue for peripheral nerve repair. Stem Cells International, 2016 , Article 7502178. https://doi.org/10.1155/2016/7502178 Herzog, M. M., Marshall, S. W., Lund, J. L., Pate, V., Mack, C. D., & Spang, J. T. (2017). Cost of outpatient arthroscopic ACL reconstruction among commercially insured patients in the United States, 2005–2013. Orthopaedic Journal of Sports Medicine, 5 (1), 2325967116684776. https://doi.org/10.1177/2325967116684776 Varsheya, K., Raabe, D., Lendner, M., & King, J. J. (2022). Single-stage surgical treatment of multi-ligament knee injuries results in lower cost and fewer complications compared with staged treatment. Arthroscopy, Sports Medicine, and Rehabilitation, 4 (6), e1751–e1759. https://doi.org/10.1016/j.asmr.2022.06.012 Zhang, J. Y., Gray, A. M., Redler, L. H., & Dines, J. S. (2015). Rehabilitation charges associated with anterior cruciate ligament reconstruction. Sports Health, 7 (6), 538–541. https://doi.org/10.1177/1941738115606878 Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6831237","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":467242681,"identity":"8546f8d1-b69f-4715-9b96-f905fe4ee424","order_by":0,"name":"Ugur Dogan","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzUlEQVRIiWNgGAWjYLCCDwwSDAzspOhgnMEgIcHAzEyCFmYeBgYStBicX2P22bbNoo6/mf/g44KKOgb+9u4E/FpuvDGendsmISFxmJnZeMaZwwwSZ85uIKDljDFzzhmgXw4zs0nzth1gMJDIJUKLBVCLPFjLvzoitJzvMWZmqJCQMABraWAmrEXyBlsxY0+FhOTGw8zGxjzHDvMQ9Avf+cObGX4Y1PHLHW98+Jinpk6Ov70XvxYGiQRUPg9+5SDAf4CwmlEwCkbBKBjhAACKvDy5QnryrwAAAABJRU5ErkJggg==","orcid":"","institution":"Vital Tones, Rotterdam, Netherlands","correspondingAuthor":true,"prefix":"","firstName":"Ugur","middleName":"","lastName":"Dogan","suffix":""},{"id":467242682,"identity":"78e90fba-597d-406c-b651-2828893774e4","order_by":1,"name":"Tahreem Fatima","email":"","orcid":"","institution":"CNS Lab, Macquarie University Hospital, Macquarie University, Sydney, Australia","correspondingAuthor":false,"prefix":"","firstName":"Tahreem","middleName":"","lastName":"Fatima","suffix":""},{"id":467242683,"identity":"d3d15da8-075a-4a97-ab00-9a84c885943f","order_by":2,"name":"Umar Hassan","email":"","orcid":"","institution":"Department of Radiology, National Hospital \u0026 Medical Centre, Lahore, Pakistan","correspondingAuthor":false,"prefix":"","firstName":"Umar","middleName":"","lastName":"Hassan","suffix":""}],"badges":[],"createdAt":"2025-06-05 17:24:35","currentVersionCode":1,"declarations":{"humanSubjects":true,"vertebrateSubjects":false,"conflictsOfInterestStatement":false,"humanSubjectEthicalGuidelines":true,"humanSubjectConsent":true,"humanSubjectClinicalTrial":false,"humanSubjectCaseReport":true,"vertebrateSubjectEthicalGuidelines":false},"doi":"10.21203/rs.3.rs-6831237/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6831237/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":84341838,"identity":"e6a19423-97fe-40d4-9343-318eecec89dc","added_by":"auto","created_at":"2025-06-10 18:41:55","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":219197,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSagittal T2-weighted MRI images of the right knee\u003c/strong\u003e.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLeft (A:\u003c/strong\u003e 20 Dec 2017- Disrupted ACL and PCL fibers, 1.5 T)\u003cstrong\u003e:\u003c/strong\u003e Pre-treatment sagittal MRI shows an ACL and PCL tear with discontinuity and absence of the normal low-signal band in the intercondylar notch, replaced by ill-defined high-signal tissue. \u003cstrong\u003eRight (B:\u003c/strong\u003e 2 May 2025 - Continuous, intact ACL and PCL with normal signal, 1.5 T)\u003cstrong\u003e:\u003c/strong\u003ePost-treatment image reveals a well-positioned low-signal ACL, PCL with restoration of continuity and anatomical orientation within the intercondylar notch, consistent with successful ACL, PCL reconstruction.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-6831237/v1/b36ba52b50083c492786b3af.png"},{"id":84340555,"identity":"80a458f4-4cbf-49fd-93ad-fc3eb543eefb","added_by":"auto","created_at":"2025-06-10 18:25:55","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":227258,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eCoronal MRI views of the posterior cruciate ligament (PCL) at its tibial insertion site. Left\u003c/strong\u003e (\u003cstrong\u003eA:\u003c/strong\u003e 20 Dec 2017 — Poor fiber continuity in cruciate ligament regions.): Pre-treatment image (2017) shows discontinuity and disorganisation at the PCL tibial insertion with irregular fibre morphology and abnormal signal intensity. \u003cstrong\u003eRight\u003c/strong\u003e (\u003cstrong\u003eB:\u003c/strong\u003e 2 May 2025 — Restored ligament alignment and contour.): Post-treatment image (2025) reveals a well-defined, continuous PCL inserting onto the posterior tibia, with restoration of normal signal and anatomical fibre alignment. These changes support structural ligament healing at the insertional footprint.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-6831237/v1/cc47acf66765abf1040d76c6.png"},{"id":84340560,"identity":"647d7009-be97-49f3-a159-8f043e75f867","added_by":"auto","created_at":"2025-06-10 18:25:55","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":216510,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eSagittal MRI comparison of the posterior cruciate ligament (PCL) before and after treatment.\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eLeft(A):\u003c/strong\u003e Pre-treatment image (2017) demonstrates a high-grade PCL tear with thickened, ill-defined, and discontinuous fibres. The ligament appears wavy and disrupted, with altered signal intensity. \u003cstrong\u003eRight(B):\u003c/strong\u003e Post-treatment image (2025) shows a well-defined, continuous PCL of normal calibre and orientation, with restoration of anatomical structure and signal integrity. These findings are consistent with successful ligament healing without surgical reconstruction.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-6831237/v1/07d682c8f8e68bb3408e3c3f.png"},{"id":84342156,"identity":"2ff599c1-dfd0-4b41-9495-19f59fa0d361","added_by":"auto","created_at":"2025-06-10 18:49:55","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1716618,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6831237/v1/88c45367-3228-49cb-95f1-4aab2a63507f.pdf"}],"financialInterests":"The authors declare no competing interests.","formattedTitle":"\u003cp\u003e\u003cstrong\u003eAudio Brainwave Treatment Restores Chronic ACL–PCL Ruptures: MRI-Verified Case Report\u003c/strong\u003e\u003c/p\u003e","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eACL reconstruction is common, yet only about 60\u0026ndash;70% of patients regain their pre-injury sport performance and secondary ligament failure remains a concern [\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. Combined ACL\u0026ndash;PCL injuries impose greater surgical complexity and longer rehabilitation, with staged or single-stage reconstructions often requiring\u0026thinsp;\u0026ge;\u0026thinsp;6 months before high-pivot activities can be resumed [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Surgical morbidity, prolonged work absence, and incomplete return to sport have therefore driven interest in biologic or regenerative alternatives.\u003c/p\u003e \u003cp\u003eDeep Brain Sound Stimulation (DBSS) is a non-invasive auditory neuromodulation method that employs precisely tuned monaural and isochronic tones to elicit frequency-following responses in targeted brain circuits. Since its inception in 2014, over 100 DBSS protocols have been developed and released as part of an ongoing research and development initiative. These applications span a wide range of use cases\u0026mdash;including psychiatric, neurological, pain management, sleep regulation, and physical rehabilitation\u0026mdash;with user feedback consistently indicating satisfaction rates above 97% [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Though not formally established as clinical treatments, DBSS protocols are informed by existing scientific literature and are iteratively refined based on user-reported outcomes. In one published case, DBSS influenced periventricular activity and coincided with MRI-documented shrinkage of a porencephalic cyst alongside motor function improvement [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe subventricular zone (SVZ) is the principal neural stem cell niche in the adult brain. Although direct evidence of SVZ-derived cells repairing peripheral tissues is lacking, recent work has identified SVZ-like progenitors in peripheral organs and shown that Pigment Epithelium-Derived Factor (PEDF)-derived neurotrophic peptides accelerate tendon healing [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Together these findings suggest that activating the SVZ could trigger reparative signaling beyond the CNS. We therefore hypothesize that SVZ stimulation may promote regeneration of damaged knee ligaments.\u003c/p\u003e \u003cp\u003eWe report a rare case\u0026mdash;confirmed by serial MRI\u0026mdash;of complete radiological and functional healing of chronic ACL and PCL tears after a three-week DBSS program.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"2. Patient Information","content":"\u003cp\u003eA 35-year-old physically active man injured his right knee while playing recreational soccer in December 2017. He declined graft surgery for family and prior-surgery reasons.\u003c/p\u003e \u003cp\u003e \u003cb\u003ePrior management (2017\u0026ndash;2024)\u003c/b\u003e \u003c/p\u003e \u003cp\u003eThe patient intermittently used oral non-steroidal anti-inflammatory drugs (NSAIDs) and topical counter-irritant creams, with limited relief. A self-guided weight-loss effort in 2018 led to ~\u0026thinsp;5 kg reduction and modest symptom improvement. No structured physiotherapy, bracing, or intra-articular therapies were undertaken. Throughout this period, he experienced daily knee aching rated 6/10 on the 11-point NRS, especially during walking, running, and squatting. In October 2024, he consulted the senior author (a relative) and consented to a trial of a knee-targeted DBSS protocol designed to activate SVZ stem-cell activity.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"3. Clinical Timeline","content":"\u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDate\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEvent \u0026amp; findings\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20 Dec 2017\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMRI #1 (1.5 T): complete ACL tear, high-grade PCL tear.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2017\u0026ndash;2024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNSAIDs, creams, ~\u0026thinsp;5 kg weight loss; pain stable NRS 6.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e15 Oct 2024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDBSS started: two 25-min sessions once daily.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e17 Oct 2024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePain 0/10 at rest and during normal activity.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e5 Nov 2024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eCourse completed (20/21 days; 99% adherence, no adverse effects).\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e6\u0026ndash;19 Nov 2024\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eListened again for reassurance; pain remained 0/10.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e20 Nov 2024\u0026ndash;14 May 2025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo further DBSS or treatment; remains pain-free and fully active.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e2 May 2025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMRI #2 (1.5 T): continuous ACL \u0026amp; PCL, no effusion; DICOM dataset\u0026mdash;see Data-Availability.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"4. Therapeutic Intervention","content":"\u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Tabb\" border=\"1\"\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eItem\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eDetails\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDelivery Format\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eTwo FLAC audio files (Vital Tones), played with standard over-ear headphones.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eProtocol\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMulti-segment knee program: both 25-min sessions sequentially stimulate SVZ sub-regions mapped to the full knee joint.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSignal characteristics\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMulti-frequency monaural \u0026amp; isochronic tones, selected from the 100\u0026ndash;260 Hz range, engineered to entrain SVZ activity and bias reparative signalling to the knee [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEquipment\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eOver-ear consumer headphones (20 Hz\u0026ndash;20 kHz); bilateral listening (both ears) was used in this case.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDosage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eBoth sessions once daily \u0026times; 21 days.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAdherence\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e99%; no adverse effects.\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAvailability\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAudio files (non-profit research use) and DICOM dataset\u0026mdash;see Data-Availability\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFuture recommendation\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eA four-week schedule is suggested for prospective studies to accommodate larger or more complex tears\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"5. Outcomes (October 2024 – May 2025)","content":"\u003cp\u003e\u003cstrong\u003e5.1 Symptom course\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e● \u003cstrong\u003ePain:\u003c/strong\u003e Baseline NRS 6/10 \u0026rarr; 0/10 within 48 h; 0/10 maintained through 14 May 2025.\u003c/p\u003e\n\u003cp\u003e● \u003cstrong\u003eAdverse effects:\u003c/strong\u003e None reported during or after the 21-day intervention, including the brief reassurance-listening period (6\u0026ndash;19 Nov 2024).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e5.2 Functional status\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e●\u0026nbsp; \u0026nbsp; \u0026nbsp;By day 2, the patient resumed all routine daily and occupational activities\u0026mdash;including walking rounds, stair use, squatting, and household tasks\u0026mdash;without discomfort or instability.\u003c/p\u003e\n\u003cp\u003e●\u0026nbsp; \u0026nbsp; \u0026nbsp;He has maintained unrestricted activity for seven consecutive months and gained approximately 5\u0026ndash;6 kg without recurrence of pain.\u003c/p\u003e\n\u003cp\u003e●\u0026nbsp; \u0026nbsp; \u0026nbsp;No formal sport-specific testing was performed, but the patient reports that every movement attempted has remained pain-free.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e5.3 Imaging findings\u003c/strong\u003e\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"623\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eParameter\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 228px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMRI #1 (20 Dec 2017, 1.5 T)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 270px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eMRI #2 (2 May 2025, 1.5 T)\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eACL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 228px;\"\u003e\n \u003cp\u003eComplete tear with fibre discontinuity\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 270px;\"\u003e\n \u003cp\u003eContinuous ligament of normal calibre and orientation\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003ePCL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 228px;\"\u003e\n \u003cp\u003eHigh-grade tear\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 270px;\"\u003e\n \u003cp\u003eContinuous ligament of normal calibre and orientation\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 126px;\"\u003e\n \u003cp\u003eSurgical artefact\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 228px;\"\u003e\n \u003cp\u003eNone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 270px;\"\u003e\n \u003cp\u003eNone\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003eRadiologist impression (May 2025):\u003c/strong\u003e\u003cbr\u003e\u0026nbsp;\u0026ldquo;Anterior and posterior cruciate ligaments are intact; no evidence of prior reconstruction.\u0026rdquo;\u003c/p\u003e\n\u003cp\u003eRepresentative sagittal and coronal slices are shown in \u003cstrong\u003eFigure 1\u0026ndash;3\u003c/strong\u003e. Complete pre- and post-treatment DICOM datasets are available for independent review (see Data-Availability).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e5.4 Patient perspective\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u0026ldquo;Two days after starting the sound sessions, the pain was gone. Since then I\u0026rsquo;ve walked, worked, and played with my family without thinking about my knee. It feels completely normal.\u0026rdquo;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e5.5 Summary\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDBSS was associated with rapid pain relief and MRI-verified continuity of both cruciate ligaments, without any adjunct treatment.\u003c/p\u003e"},{"header":"6. Discussion","content":"\u003cp\u003e \u003cb\u003ePrincipal findings\u003c/b\u003e \u003c/p\u003e \u003cp\u003eA patient with MRI-verified combined ACL and PCL tears lived with daily pain for seven years. Within 48 hours of beginning a three-week DBSS program, the pain disappeared, and five-month follow-up MRI showed continuous cruciate-ligament fibres without surgical intervention. Because adult full-thickness ACL ruptures seldom regain anatomical continuity after conservative care, and combined ACL\u0026ndash;PCL injuries heal even less frequently without reconstruction [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], the recovery observed here is unlikely to be spontaneous.\u003c/p\u003e \u003cp\u003e \u003cb\u003ePutative mechanism\u003c/b\u003e \u003c/p\u003e \u003cp\u003eDBSS delivers monaural/isochronic tones designed to entrain the SVZ. Recent work shows that SVZ neural stem cells secrete systemic growth factors and can even enhance peripheral nerve repair when transplanted outside the CNS [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. We therefore propose that DBSS up-regulates this circulating trophic output and directs it to the knee, accelerating collagen remodelling until structural integrity is restored. Because the two 25-min sessions sequentially map the whole knee capsule\u0026mdash;not just the cruciate bundle\u0026mdash;any concomitant collateral-ligament or meniscal defects should theoretically receive the same reparative cue. Serial MRI in future trials can determine how soon fibre continuity appears relative to the early analgesic effect.\u003c/p\u003e \u003cp\u003e \u003cb\u003eClinical relevance\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eUniversal applicability.\u003c/b\u003e A non-invasive, home-based audio protocol may benefit any patient with cruciate-ligament rupture\u0026mdash;not only athletes seeking rapid return but also older adults whose degenerated ligaments might be strengthened before failure.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003e \u003cb\u003eCost and convenience.\u003c/b\u003e A one-off \u0026euro; \u0026lt; 100 download avoided hospitalisation, lengthy physiotherapy, and work loss; recent U.S. data place median 9-month healthcare spending for ACL reconstruction at ~\u0026euro;12 500\u0026ndash;\u0026euro;15 000, rising to \u0026gt;\u0026euro;20 000 when multiple ligaments are repaired, and staged ACL\u0026ndash;PCL surgery can exceed \u0026euro;28 000 [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Supervised rehabilitation alone commonly adds a further \u0026euro;1 500\u0026ndash;\u0026euro;3 500 in therapy charges [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e].\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eLimitations\u003c/b\u003e \u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eSingle-case design without instrumented laxity testing or blinded assessment.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003ePlacebo or expectancy effects cannot be excluded, although durable MRI normalisation supports a biological mechanism.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eAudio parameters remain proprietary; replication files omit exact frequency values and modulation details.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe mechanistic link between SVZ entrainment and ligament healing is still speculative; future human studies should combine serial MRI with circulating growth-factor or exosome profiling to confirm the regenerative pathway.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eFuture directions\u003c/b\u003e \u003c/p\u003e \u003cp\u003eProspective, controlled studies should:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eObtain MRI at multiple time points (e.g., 2, 4, 8 weeks) to map healing kinetics.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eInclude quantitative laxity and functional tests.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eOptimise protocol parameters\u0026mdash;session duration, total weeks, and bilateral vs knee-specific unilateral listening\u0026mdash;to identify the fastest effective schedule.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eEvaluate other ligament and tendon injuries (rotator cuff, Achilles, ulnar collateral ligament) to test the generalisability of DBSS.\u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003cp\u003eColleagues who use the freely available protocol are invited to share de-identified pre- and post-treatment MRI datasets with the author for inclusion in a pooled follow-up report.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"7. Conclusion","content":"\u003cp\u003eThis case documents complete, MRI-verified healing of chronic ACL and PCL ruptures after a three-week course of Deep Brain Sound Stimulation. Pain ceased within 48 h and has not recurred in seven months of unrestricted daily activity. The finding supports the hypothesis that SVZ-targeted neuromodulation may facilitate clinically meaningful, extra-neural tissue repair. Well-designed prospective trials\u0026mdash;combining serial imaging, quantitative laxity testing, and blood-borne biomarker analysis\u0026mdash;are now justified to confirm efficacy, define healing kinetics, and explore application to other ligaments and tendons.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eData-Availability Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e● \u003cstrong\u003eImaging:\u003c/strong\u003e Anonymized pre- and post-treatment DICOM MRI files are available upon reasonable request. Please contact the corresponding author via email ([email protected]) for access instructions.\u003c/p\u003e\n\u003cp\u003e● \u003cstrong\u003eAudio protocol:\u003c/strong\u003e The two 25-minute DBSS audio sessions, manual, and streaming access are released for non-commercial research use via online registration (secure Google Form): https://forms.gle/YC35TgH6f7LJhSDu7\u003c/p\u003e\n\u003cp\u003e● \u003cstrong\u003eCase contribution:\u003c/strong\u003e Registered users receive an encrypted upload link (HIPAA/GDPR compliant) to share de-identified pre/post MRI ZIPs and brief clinical notes. ≥3 complete cases qualify for group authorship in pooled follow-up studies; single cases earn formal acknowledgment or a certificate. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e● \u003cstrong\u003eAdditional materials:\u003c/strong\u003e Related publications are available upon request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e: No external funding was received for this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflicts of Interest\u003c/strong\u003e: Uğur Doğan is the founder and chief technology officer of Vital Tones, developer of the DBSS audio protocols. No other financial or non-financial conflicts are declared.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Approval\u003c/strong\u003e: Institutional review board approval was waived in accordance with institutional policy for single-patient case reports.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePatient Consent\u003c/strong\u003e: Written informed consent was obtained for publication of this case and associated anonymized MRI DICOM files.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e: The author thanks the patient for his cooperation and permission to share his experience.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eRandsborg, P-H., Cepeda, N., Adamec, D., Rodeo, S. A., Ranawat, A., \u0026amp; Pearle, A. D. (2022). Patient-reported outcome, return to sport, and revision rates 7\u0026ndash;9 years after anterior cruciate ligament reconstruction: Results from a cohort of 2042 patients. \u003cem\u003eAmerican Journal of Sports Medicine, 50\u003c/em\u003e(2), 423\u0026ndash;432. https://doi.org/10.1177/03635465211060333\u003c/li\u003e\n\u003cli\u003eWiggins, A. J., Grandhi, R. K., Schneider, D. K., Stanfield, D., Webster, K. E., \u0026amp; Myer, G. D. (2016). Risk of secondary injury in younger athletes after anterior cruciate ligament reconstruction: A systematic review and meta-analysis. \u003cem\u003eAmerican Journal of Sports Medicine, 44\u003c/em\u003e(7), 1861\u0026ndash;1876. https://doi.org/10.1177/0363546515621554\u003c/li\u003e\n\u003cli\u003eSchwery, N. A., Kiely, M. T., Larson, C. M., Wulf, C. A., Heikes, C. S., Hess, R. W., et al. (2022). Quadriceps strength following anterior cruciate ligament reconstruction: Normative values based on sex, graft type and meniscal status at 3, 6 \u0026amp; 9 months. \u003cem\u003eInternational Journal of Sports Physical Therapy, 17\u003c/em\u003e(3), 434\u0026ndash;444. https://doi.org/10.26603/001c.32378\u003c/li\u003e\n\u003cli\u003eFanelli, G. C., \u0026amp; Edson, C. J. (2020). Combined ACL-PCL-medial and lateral side injuries (global laxity). \u003cem\u003eSports Medicine and Arthroscopy Review, 28\u003c/em\u003e(3), 100\u0026ndash;109. https://doi.org/10.1097/JSA.0000000000000276\u003c/li\u003e\n\u003cli\u003eDoğan, U. (2025). \u003cem\u003ePrecision auditory stimulation using Deep Brain Sound technology for neurological and psychiatric conditions: Large-scale observational study\u003c/em\u003e [Preprint, Zenodo]. https://doi.org/10.5281/zenodo.15449609\u003c/li\u003e\n\u003cli\u003eDoğan, U., \u0026amp; Tahreem, F. (2023). Reduction of porencephalic cyst along with the revival of motor control using the Deep Brain Sound Stimulation (DBSS) technology as a novel approach. \u003cem\u003eBiomedical Science and Clinical Research, 2\u003c/em\u003e(1), 144\u0026ndash;148. https://doi.org/10.33140/BSCR.02.01.11\u003c/li\u003e\n\u003cli\u003eXu, W., Wang, J., Li, P., Zhang, Y., Chen, H., \u0026amp; Zhou, Q. (2025). Multipotent neural stem cells originating from neuroepithelium exist outside the mouse central nervous system. \u003cem\u003eNature Cell Biology, 27\u003c/em\u003e(5), 605\u0026ndash;618. https://doi.org/10.1038/s41556-025-01641-w\u003c/li\u003e\n\u003cli\u003eHo, T. C., Chau, Y. P., Liu, H. L., Chen, L. J., Chiu, S. J., \u0026amp; Chang, S. Y. (2019). PEDF-derived peptide promotes tendon regeneration through its mitogenic effect on tendon stem/progenitor cells. \u003cem\u003eStem Cell Research \u0026amp; Therapy, 10\u003c/em\u003e, Article 2. https://doi.org/10.1186/s13287-018-1110-z\u003c/li\u003e\n\u003cli\u003eBlanke, F., Trinnes, K., Oehler, N., Prall, W. C., Lutter, C., Tischer, T., \u0026amp; Vogt, S. (2023). \u003cem\u003eSpontaneous healing of acute ACL ruptures: Rate, prognostic factors and short-term outcome\u003c/em\u003e. \u003cem\u003eArchives of Orthopaedic and Trauma Surgery, 143\u003c/em\u003e(7), 4291\u0026ndash;4298. https://doi.org/10.1007/s00402-022-04701-0\u003c/li\u003e\n\u003cli\u003eSuneja, A., Deshpande, S. V., Wamborikar, H., Date, S. V., Goel, S., \u0026amp; Sekhon, G. (2023). Outcome analysis of posterior cruciate ligament injuries: A narrative review. \u003cem\u003eCureus, 15\u003c/em\u003e(10), e47410. https://doi.org/10.7759/cureus.47410\u003c/li\u003e\n\u003cli\u003eBhangra, K. S., Busuttil, F., Phillips, J. B., \u0026amp; Rahim, A. A. (2016). Using stem cells to grow artificial tissue for peripheral nerve repair. \u003cem\u003eStem Cells International, 2016\u003c/em\u003e, Article 7502178. https://doi.org/10.1155/2016/7502178\u003c/li\u003e\n\u003cli\u003eHerzog, M. M., Marshall, S. W., Lund, J. L., Pate, V., Mack, C. D., \u0026amp; Spang, J. T. (2017). Cost of outpatient arthroscopic ACL reconstruction among commercially insured patients in the United States, 2005\u0026ndash;2013. \u003cem\u003eOrthopaedic Journal of Sports Medicine, 5\u003c/em\u003e(1), 2325967116684776. https://doi.org/10.1177/2325967116684776\u003c/li\u003e\n\u003cli\u003eVarsheya, K., Raabe, D., Lendner, M., \u0026amp; King, J. J. (2022). Single-stage surgical treatment of multi-ligament knee injuries results in lower cost and fewer complications compared with staged treatment. \u003cem\u003eArthroscopy, Sports Medicine, and Rehabilitation, 4\u003c/em\u003e(6), e1751\u0026ndash;e1759. https://doi.org/10.1016/j.asmr.2022.06.012\u003c/li\u003e\n\u003cli\u003eZhang, J. Y., Gray, A. M., Redler, L. H., \u0026amp; Dines, J. S. (2015). Rehabilitation charges associated with anterior cruciate ligament reconstruction. \u003cem\u003eSports Health, 7\u003c/em\u003e(6), 538\u0026ndash;541. https://doi.org/10.1177/1941738115606878\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"Vital Tones, Rotterdam, Netherlands","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"anterior cruciate ligament, posterior cruciate ligament, subventricular zone, deep brain sound stimulation, audio neuromodulation, regenerative medicine, non-invasive treatment","lastPublishedDoi":"10.21203/rs.3.rs-6831237/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6831237/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground: \u003c/strong\u003eChronic combined anterior- and posterior-cruciate-ligament (ACL/PCL) ruptures typically require graft reconstruction and 6–9 months of rehabilitation, yet many patients fail to regain full functional capacity. Deep Brain Sound Stimulation (DBSS) is a non-invasive audio neuromodulation platform that can entrain selected brain circuits; in this prototype protocol, DBSS targeted the subventricular zone (SVZ) to enhance reparative signalling toward the knee.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCase: \u003c/strong\u003eA 35-year-old man sustained right-knee ACL and PCL tears in 2017. Daily pain rated 6/10 on the Numeric Rating Scale (NRS) persisted despite conservative care.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eIntervention: \u003c/strong\u003eTwo proprietary DBSS audio sessions (25 min each; monaural/isochronic tones selected from the 100–260 Hz range) were used once daily for 21 days to deliver SVZ-targeted stimulation of the knee. Audio files are freely downloadable for non-profit replication; exact frequency parameters remain confidential.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults: \u003c/strong\u003ePain resolved to 0/10 within 48 hours and has remained absent since. MRI at follow-up showed fully intact ACL and PCL fibres with no residual tear or surgical intervention.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions: \u003c/strong\u003eDBSS-mediated SVZ activation was associated with rapid, durable, MRI-verified healing of chronic dual-cruciate ruptures. A low-cost, home-based audio intervention may benefit a broad population—from competitive athletes to older adults—if confirmed in controlled trials with serial MRI, laxity testing, and biomarker profiling.\u003c/p\u003e","manuscriptTitle":"Audio Brainwave Treatment Restores Chronic ACL–PCL Ruptures: MRI-Verified Case Report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-10 18:25:50","doi":"10.21203/rs.3.rs-6831237/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"6916f0f9-40fb-41bc-bdec-a6041be00adf","owner":[],"postedDate":"June 10th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":49610759,"name":"Cell \u0026 Tissue Engineering"},{"id":49610760,"name":"Stem Cell \u0026 Developmental Cell Biology"},{"id":49610761,"name":"Sports Medicine and Kinesiology"},{"id":49610762,"name":"Orthopedics"},{"id":49610763,"name":"Orthopedic Surgery"},{"id":49610764,"name":"Neurology"},{"id":49610765,"name":"Biomedical Engineering"},{"id":49610766,"name":"Renewable Resources"},{"id":49610767,"name":"Cellular Metabolism"},{"id":49610768,"name":"Evolutionary Developmental Biology"},{"id":49610769,"name":"Biotechnology and Bioengineering"},{"id":49610770,"name":"Cell Communication and Signaling"},{"id":49610771,"name":"Cellular \u0026 Molecular Neuroscience"},{"id":49610772,"name":"Developmental Neuroscience"},{"id":49610773,"name":"Rheumatology"}],"tags":[],"updatedAt":"2025-06-10T18:25:50+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-10 18:25:50","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6831237","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6831237","identity":"rs-6831237","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}