The Safe and Sound Protocol (SSP) is an auditory intervention that uses specially filtered music to help calm the nervous system. Developed by neuroscientist Stephen Porges, it’s designed to reduce anxiety, sensory sensitivities, and stress-related symptoms by training the muscles of the middle ear to better process human speech frequencies. The protocol is used by therapists working with children and adults who experience autism spectrum challenges, trauma, anxiety, and difficulties with emotional regulation.
How the Protocol Works
The SSP is built on a simple but powerful idea: the tiny muscles inside your middle ear play a role in how safe or threatened your nervous system feels. These are the smallest striated muscles in the human body, with fibers only 1 to 2 millimeters long. They act as both sensors and actuators, stiffening in response to sound vibration to filter what reaches your inner ear. When these muscles are functioning well, they help you tune in to the frequencies of human speech and tune out low-frequency background noise that your brain may interpret as threatening.
In people with trauma histories, autism, or chronic anxiety, this filtering system can get stuck in a defensive mode. The nervous system stays on alert, making it harder to process social cues from voices and easier to feel overwhelmed by environmental sounds. The SSP uses acoustically modified music, delivered through over-the-ear headphones, to exercise these middle ear muscles and gradually shift the nervous system out of that defensive state. Porges describes it as a “neural exercise” that promotes more efficient regulation of the body’s automatic arousal systems.
What It’s Used For
The SSP was originally studied in children with autism spectrum disorders, where research showed improvements in autonomic function, auditory hypersensitivities, and emotion regulation. Since then, its use has expanded significantly. Therapists now use it for post-traumatic stress, generalized anxiety, sensory processing difficulties, and conditions involving chronic nervous system dysregulation.
For people with PTSD specifically, the protocol targets the heightened state of arousal that drives symptoms like hypervigilance, irritability, and exaggerated startle responses. These symptoms often reflect a nervous system that has become locked into threat-detection mode. The SSP aims to reduce that threat-responsive tuning, increasing the body’s ability to self-regulate during stressful moments. A pilot study on trauma survivors found it reduced both PTSD symptoms and anxiety. Separate research on adults with voice, throat, and breathing complaints found significant decreases in anxiety, depression, and autonomic reactivity after completing the protocol.
What the Experience Looks Like
You listen to specially filtered music through over-the-ear headphones using an app on your phone or tablet. The music sounds like regular songs (often pop or classical tracks) but has been processed to emphasize certain frequency ranges that engage the middle ear muscles. A trained provider assigns you a playlist and monitors your progress, either in person or remotely.
The protocol is passive in the sense that you don’t have to do anything beyond listening. Sessions are typically short, and the full initial course can be completed in as few as five days for children, though some people take longer. Results have been observed in as little as five days but may take up to three months depending on the individual and the severity of their symptoms.
One important point: the SSP is generally most effective when paired with other therapeutic work. Occupational therapy, psychotherapy, or other trauma-informed treatments help solidify the nervous system changes the protocol initiates. On its own, the SSP can produce noticeable shifts in how calm or regulated someone feels, but practitioners consistently recommend it as one component of a broader treatment plan rather than a standalone fix.
Who Delivers It
The SSP is only available through trained providers. You cannot purchase or access the filtered music on your own. Providers include occupational therapists, psychologists, speech-language pathologists, and other licensed clinicians who complete a certification course through Unyte Health (formerly Integrated Listening Systems), the company that holds the license for the protocol.
Remote delivery is available, which expanded access significantly during and after 2020. Your provider assigns listening sessions through the Unyte app, and you complete them at home while staying in contact with your provider to adjust pacing if needed. Some people find certain sessions emotionally activating, so having professional guidance helps manage the process safely.
Cost and Access
You typically pay your provider’s session fee, which varies by practitioner and location. On the provider side, subscriptions to access the SSP platform start at $139 per month on an annual plan, plus a one-time training fee of $249 to $349. These costs are passed along to clients in different ways depending on the practice. Some providers bundle the SSP into a package of therapy sessions, while others charge a separate fee for the listening program.
There is no widely available information on insurance coverage for the SSP specifically. Some clients may be able to use health savings accounts or flexible spending accounts if their provider codes the sessions as part of a covered therapy type like occupational therapy or speech therapy, but this varies by plan and insurer.
The Science Behind It
The SSP is rooted in Porges’ Polyvagal Theory, which describes how the vagus nerve and autonomic nervous system regulate feelings of safety, social connection, and threat response. The theory proposes that humans have three distinct nervous system states: a calm, socially engaged state; a fight-or-flight state; and a shutdown or freeze state. The SSP is designed to help people access the first of these states more easily.
The clinical evidence base is growing but still relatively small. Published studies have shown positive outcomes for autonomic regulation, anxiety reduction, and sensory processing in populations ranging from children with autism to adults with trauma histories and voice disorders. Most of these studies involve small sample sizes, and larger controlled trials are still needed to establish the protocol’s effectiveness across different conditions with greater certainty. That said, the existing results are consistent enough that the SSP has gained traction among therapists who work with nervous system dysregulation, and many report meaningful clinical improvements in their clients.