Developed by Dr. Stephen Porges, the Safe and Sound Protocol (SSP) is a five-day auditory intervention designed to reduce stress and auditory sensitivity while enhancing social engagement and resilience. Based on Dr. Porges’ Polyvagal Theory, by calming the physiological and emotional state, the door is opened for improved communication and more successful therapy.


How does the SSP work? 

The intervention uses prosodic vocal music that has been filtered to train the middle ear muscles to focus on the frequency envelope of human speech. Once human speech is properly perceived, the portal to social engagement has been opened. You will find you (or your child) is better able to interpret not only the meaning, but also the intent of conversations.  And the sense of safety that is achieved by better understanding the fluctuations in human voice calms your (or your child’s) physiological state. Once the nervous system has been primed, and your physiological state is calm, further therapy is enhanced and behavioural regulation is improved. 

The SSP is a research-based therapy showing significant results in just five days in the following areas:

  • Social and emotional difficulties
  • Auditory sensitivities
  • Anxiety and trauma related challenges
  • Inattention
  • Stressors that impact social engagement


Safe and Sound Protocol Information sheet

The purpose of the Safe & Sound Protocol (SSP) is to initiate and access a physiological state conducive to well-being, positive engagement with others, and growth in learning and therapy.

Rooted in his Polyvagal Theory, Dr. Stephen Porges created the SSP to help people learn to attain a grounded state where they feel safe, connected, calm and social.

By helping to access a calm and grounded state, the SSP promotes a neural platform for health, growth and restoration.


What is Physiological State?

Physiological or emotional state is at the root of all behaviour. Some states promote sociability. Some promote tantrums. Others promote shut down.

  • What is the “just right” state for therapy? It’s the sweet spot where a person is available and motivated for the task at hand.
  • How do you know when your client or student is in the perfect state for optimal performance? You’ll notice signals in the: eyes (bright and focused); face (content with the ability to express all emotions); voice (capable of prosody or tone changes); body (relaxed but with good muscle tone); and rate of movement (smooth and responsive – not too fast or slow).
  • These are all indicators of a state of focused, relaxed, and confident alertness optimal for learning and performing with confidence.

State is critical to how we approach the task at hand. So when a client has better state control, not only can they be more socially engaged, they are more open to therapy. Better state regulation improves therapeutic outcomes.


What is the Polyvagal Theory? 

The Polyvagal Theory describes the evolutionary hierarchy of our autonomic nervous responses, central to which is the vagus nerve. The Social Engagement System (SES) is our highest level and newest (in evolutionary terms) strategy for self-regulation. It is triggered by signals of safety and puts the brakes on defensive strategies, allowing us to rest and digest (our parasympathetic system).

If we sense danger, however, the SES will release the brakes to engage a more primitive response: that of fight or flight (our sympathetic system). And if we detect life threat, our response may devolve even further to immobilization, or freezing behaviour (like a deer in headlights). None of these responses can be reasoned; they all occur unconsciously via neuroception, the body’s ability to perceive threat outside of our awareness.


Plasticity of the Autonomic Nervous System and State

The SSP exercises the neural pathways associated with regulating behavioural state and social engagement. These are aspects of the Autonomic Nervous System (ANS). And just as the brain is plastic and can change based on experience, the ANS is also plastic. Peer-reviewed research has shown the SSP to significantly increase vagal regulation of the heart, which promotes better control of our state.


What is the Social Engagement System? 

Critical to healthy engagement with the world, the Social Engagement System (SES) interprets cues from our social environment, like vocal prosody, eye contact and facial gestures to gauge our level of safety. Sensing safety, the SES allows us to participate genuinely with others and be open and willing to accept new ideas.


What is the Vagus Nerve? 

The vagus nerve carries the most bi-directional information between the brain and the body of any other nerve. It initiates in the core of the brain and travels to the depths of the gut. Along its travels, the vagus nerve affects eye movement, facial expressions, tone of voice, heart rate and heart rate variability, breathing, and the function of the spleen, liver, kidneys and intestines. It can help to reduce inflammation and to improve your immune response. It is the care-taking nerve of the body.
The vagus impacts more than just physiological processes. When you say something is “getting on my nerves” or that you have a “gut feeling”, you’re referring to the vagus nerve. Through neuroception, a term coined by Dr. Stephen Porges, the vagus nerve is assessing the safety of a situation and the mood of people you interact with. And that information is relayed to the brain.
The vagus nerve activates the parasympathetic nervous system. When the vagus is stimulated, it elicits the relaxation response, slowing your heart rate and relaying instructions to release certain proteins and enzymes to calm you down. When you are relaxed, people can see it in your face and hear it in your voice because of the vagus nerve. You are better able to: concentrate, self regulate and connect with others when you are in this more calm and safe state.


The SSP is best used together with other therapies

Changes from the SSP can be cumulative and will be enhanced by the social support the client receives and the learning opportunities they are presented. While you may notice some very positive changes while using the SSP, it is not meant to be used in isolation. The changes you see can potentiate neuroplasticity and functional change from subsequent therapy modalities.



Rather than using diagnoses to determine if the SSP is right for a particular person, we have instead referred to the features that the intervention addresses. Broadly, these can be categorized into: Social Communication; Physiological State; and Sound Sensitivity.

The following tables include direct responses from clients about the changes they or their child experienced following the five-day SSP intervention.



The SSP is a portal to the Social Engagement System and it can have powerful effects on how a client interacts with the world. Examples are: better eye contact and facial expressivity; improved understanding of speech; better emotional control; more reciprocal interactions; and increased emotional expressivity among others.



Just like the brain, the Autonomic Nervous System is plastic and can “learn” to stay more activated than necessary. Being in a state of chronic defensiveness, as in some psychiatric and behavioural disorders, compromises the social engagement system and the related neural networks “learn” to engage less.

By improving the ability to assess safety in social situations, the SSP helps clients to activate a parasympathetic state. Improving state promotes behavioural regulation.



Sensitivity to sounds is a prevalent symptom in a number of disorders. People who experience sound sensitivity may: respond negatively to unexpected or loud noises; become distracted or disturbed when there is a lot of or continuous background noise; and/or find it difficult to extract the frequencies of human speech from background noise. With the SSP, we have seen significant improvements on the SCAN-3 (a measure of auditory processing) specifically on the Filtered Words and Competing Words subtests. These respectively assess the ability to decipher human speech from background sounds and to hear equally from both ears.