Trauma-focused psychotherapies for post-traumatic stress disorder (PTSD) require waking re-engagement with traumatic memories, driving high dropout. We tested whether trauma-linked auditory cues delivered during slow-wave sleep are feasible. Of 13 patients who provided written informed consent, 6 (100% female) completed overnight Sound Exposure during Sleep (SES); none of the adverse events observed during overnight stimulation were judged by the study team to be attributable to the auditory intervention, and slow-wave sleep was preserved. Two sequential protocol versions were used: Version A (n = 2; capped at SUDs 30–40) and a no-ceiling amendment (Version B, n = 4). Post-hoc exploratory analyses (not powered for efficacy) showed Version B reduced subjective distress (mean difference −65.5%, 95% CI −104.2 to −26.7; nominal p = 0.012) and PCL-5 intrusion (−7.0; nominal p = 0.015). Findings are exploratory and require sham-controlled confirmation. Trial registration: jRCT1030230706.

M.T. is an employee of S'UIMIN Inc. M.Y. is a board member and chairperson of S'UIMIN Inc. and holds equity in the company. H.Ki. holds equity in S'UIMIN Inc. M.S. is engaged in a collaborative research project with S'UIMIN Inc. for the development of treatments for PTSD. M.S., A.H., and Y.Ki. are listed inventors on a pending international patent application covering the structured physician multi-criteria sound-determination instrument used in this study (domestic Japanese filing 2026-027927, 2026-02-24; PCT in preparation). The remaining authors declare no competing interests.

jRCT1030230706

This study was supported by institutional funding to the corresponding author and grants supporting the International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba. Detailed funding sources are listed in the Acknowledgements section of the manuscript.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The Research Ethics Committee of the National Center of Neurology and Psychiatry (NCNP), Tokyo, Japan, gave ethical approval for this work (study approval number B2023-118). The protocol amendment (Form 3 v1.91) was IRB-approved on 2025-02-17 under NCNP receipt 2024-1428 (study implementation permit issued 2025-02-20), and a subsequent amendment was IRB-approved on 2025-03-04 under NCNP receipt 2025-033 (protocol version 2.2; study implementation permit 2025-03-10). All procedures adhered to the Declaration of Helsinki. Written informed consent was obtained from all participants. The trial was prospectively registered at the Japan Registry of Clinical Trials (jRCT1030230706; registration date 2024-03-15) prior to first participant enrollment.

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

Source data underlying main and supplementary figures are provided as Source Data files, excluding direct personal identifiers (access subject to a Data Use Agreement and approval from the NCNP Ethics Committee, given the sensitive nature of trauma-related audio descriptions). Per-participant trauma-content metadata will not be disclosed publicly to minimize re-identification and re-traumatization risk; access for qualified researchers may be requested from the corresponding author.