Playing sounds during sleep as a new approach to PTSD — results of the first study in people

In one sentence

Six people with post-traumatic stress disorder (PTSD) each listened, during deep sleep on one night, to a sound related to their own traumatic experience. All six completed the night and the follow-up visit, and no adverse event was judged to have been caused by the sound. This first step shows that the method can actually be carried out in people.

Background — why sleep?

In PTSD, the memory of a life-threatening event does not fade. Nightmares and flashbacks (sudden, vivid re-living of the event) persist. The main treatments today are psychotherapies in which people face their traumatic memories while awake. They work well, but facing those memories is itself very distressing, and many people stop treatment partway through.

Sleep, by contrast, is thought to be when the brain reorganizes the day’s memories and emotions — especially during deep sleep (slow-wave sleep, the deepest stage, when brain waves become slow and large). So we asked: could we work with a traumatic memory while the person is asleep?

What we did

• The study: a physician-led feasibility study (a study that checks whether a method can be carried out safely from start to finish) — the first time this method, Sound Exposure during Sleep (SES), was tried in people. It is registered as jRCT1030230706.
• Making the sound: in the clinic, each participant worked with their physician to make a 30-second sound related to their own traumatic experience. Participants briefly listened to candidate sounds while awake and rated how distressing each one felt on a numerical scale (SUDS, Subjective Units of Distress Scale); the physician then decided whether a sound was suitable for use during sleep.
• The night: participants spent one night in a hospital clinical-research unit. Trained sleep technologists watched the brain waves, and the sound was presented only while the person was in deep sleep. On the evening before and the morning after, participants listened to the same sound while awake and rated their distress.
• Afterwards: symptoms were checked 1–4 weeks later at each participant’s usual clinic.

What we found

• The study could be completed: of the 13 people who consented, the 6 who met the study criteria (such as symptom severity and enough deep sleep measured at home) and for whom a sound was finalized all completed the night and the follow-up. The other 7 did not reach the stage of hearing a sound during sleep, either because they did not meet the criteria or because they withdrew before the night.
• Safety: no adverse event was judged to have been caused by the sound. All adverse events seen during the study were in the mildest category (grade 1).
• Exploratory observations (for reference only): for the first 2 participants, as a safety measure, we used only sounds whose distress rating when heard awake stayed at a set level (30–40 on the SUDS scale). After confirming that both had completed the night without problems, and with approval from the ethics committee, we removed this restriction. In all 4 participants after the change, distress in response to the sound was lower the next morning than the evening before; individual reductions ranged from 20% to 80%, averaging about 50%.

What these results can and cannot tell us

• The study was small (6 people) and had no comparison group that did not hear the sound.
• Distress can vary from day to day for reasons unrelated to sleep, and this study cannot tell whether the changes we saw go beyond that variation.
• Only 4 people received the procedure after the restriction was removed, so its safety is still provisional.
• We therefore cannot yet say that the method works. The next step is a larger study with a comparison group.

About the paper

This study has ended and is not recruiting participants. This page describes research and is not medical advice. We cannot respond to individual medical questions; please talk to your own doctor about treatment.