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The Safe & Sound Protocol

The Safe & Sound Protocol (SSP) is a series of listening programs based on the Polyvagal Theory as developed by Dr Steven Porges (and is distributed by Unyte iLs.) Designed to improve social engagement, SSP is the only evidence based listening protocol that is also an acoustic vagus nerve stimulator, acting as a direct reboot of the autonomic nervous system via the ears.

What is SSP?

An evidenced based sound protocol and listening programme developed by iLs (Integrated Listening Systems) and based on the ground breaking work of Dr Steven Porges, the founder of Polyvagal Theory. 

SSP affects the nervous system directly, enabling the listener/client to be more present and regulated while improving their capacity for connection and receptivity to other therapies.

How does SSP work?

Music that has been filtered to include a very precise band of frequencies is listened to via over the ear headphones. The targeted frequency range provides the listener with a gradual exposure to these sounds, which specifically stimulate the vagus and facial nerves that enable individuals to self-regulate and engage socially with others. 

Applications of SSP

The Safe and Sound Protocol promotes vastly improved social engagement by triggering relaxation and softening of the facial muscles, allowing the face to become more expressive and engaging. It also enables increased focus on conversation, as sensitivity decreases to frequencies of background noise which trigger alarm.


By bringing the nervous system out of "fight, flight, freeze" and back to the parasympathetic state of "rest & digest" homeostasis is facilitated and clients feel more settled, grounded and connected with those around them.

It is particularly effective for children and adults who experience:

  • Social and emotional difficulties

  • Auditory sensitivities

  • Auditory processing difficulties

  • Anxiety and trauma related symptoms

  • Difficulties with sustained attention

  • Difficulties with social engagement

Physiological effects of nervous system shifts
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Fuel storage, insulin activity. Endorphins that help numb and raise pain threshold


Heart rate, blood pressure, temperature, muscle tone, expressivity, eye contact, intonation, awareness of voice, sexual response, immune response. 



Blood pressure, heart rate, fuel availability,m adrenaline, oxygen to vital organs, blood clotting, pupil size


Fuel storage, insulin activity, digestion, relational ability, immune response, salivation.




Digestion, intestinal motility, immune response, rest & recuperation, circulation to non vital organs, oxytocin, ability to relate and connect,


Defensive responses

Polyvagal Theory & the Social Engagement System

The polyvagal theory (PVT), discovered by Dr. Stephen Porges in 1994, is a collection of evolutionary, neuroscientific, and psychological theories that describe the role of the vagus nerve in emotional regulation, social cues, and the fear response. It emphasises our evolutionary perspective where we needed different physiological states to feel connected with our tribe and have a sense of safety.


PVT is a vast and complex subject which you can read about in detail here.

To summarise greatly, it describes how our nervous system responds to threat (perceived or actual), and outlines three main pathways of response.

Our first port of call when registering that we are not safe is to turn to others who we trust in an attempt to re-establish safety. This is known as our Social Engagement System (SES). You can read about this system in detail here. If that fails, or the danger is more severe and imminent, then our sympathetic nervous system engages a fight or flight response to deal with the situation. If that also fails then we enter a parasympathetic, dorsal ventral, state of shutdown or immobilisation (freeze).

The way in which our body builds awareness and deals with sensory stimulation is vital to our ability to ‘learn’ and develop skills.

SSP is a 'bottom up' approach that affects us at an autonomic level, establishing a regulated and adaptive system which is then receptive to further input.

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The extraordinary power of music........

Our nervous system is highly attuned to pick up messages of threat, which when perceived cause physiological changes affecting our heartrate, breathing and visceral metabolism. The tension in our middle ear muscles (specifically the strapedius) also decreases in response to these messages, increasing our sensitivity to sounds associated with danger, and resulting in our ears becoming less sensitive to mid-range frequencies associated with the human voice (essential for communication and social engagement). 

There can't be many people who have not experienced the distinct and immediate effect that music can have on their mood, with certain songs or orchestral arrangements having the capacity to instantly raise a smile, a tear or a rush of nostalgia.


SSP capitalises on this phenomenon by training our auditory pathways to better attune to the frequency range of the human voice. Just as lifting weights can strengthen a bicep, listening to the filtered music of the protocol recruits the middle ear muscles and reinforces their ability to pick up sounds in this range.

Someone experiencing a state of fight, flight or freeze cannot distinguish between perceived and actual threats. SSP can rectify this by interrupting the reflex to divert nervous system activation and allow for enhanced social engagement. 

After completing the SSP program clients experience a calmer emotional and physiological state, promoting homeostasis and visceral regulation which in turn improves overall health. They are more able to respond appropriately to social cues and engage with others in a functional manner. 

If you think you, or someone you know, could benefit from SSP or would like to discuss it further, please contact Chloe for more information:

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