The Safe & Sound Protocol (SSP)
It is an innovative intervention designed to improve an individual’s social communication behaviors by reducing hearing sensitivities (i.e., hyperacusis) and improving the ability to process human speech. It is 5 hours of listening to specially treated music remotely or in-person.
The intervention is theoretically driven by scientific evidence relating the regulation of the middle ear muscles to:
- dampen background sounds and improve perception of human speech;
- neuroanatomical and neurophysiological circuits controlling facial expressions, vocal intonations and gestures; and
- neural circuits regulating behavioral state.
The Polyvagal Theory focuses on how function and structure changed in the vertebrate autonomic nervous system during evolution. The theory is named for the vagus, a major cranial nerve that regulates bodily state. As a function of evolution, humans and other mammals have a “new” vagal pathway that links the regulation of bodily state to the control of the muscles of the face and head including the middle ear muscles. These pathways regulating body state, facial gesture, listening (i.e., middle ear muscles), and vocal communication function collectively as a Social Engagement System.
Because the Social Engagement System is an integrated system, interventions influencing one component of this system (e.g., middle ear muscles) may impact the other components. Thus, shifts in physiological state ranging from calmness to tantrum will be reflected in the ability to process and understand human speech.
Based on the theory, this training should optimize not only verbal communication, but should also improve the regulation of affect through facial expressions, intonation of voice (i.e, prosody), gesture, and autonomic state.
The SSP, informed by the Polyvagal Theory, was developed to use a complex program of acoustic stimulation to improve the neural regulation of the middle ear muscles.[See Porges and Lewis (2010) and Kolacz, Lewis, & Porges (2018) for scientific basis of intervention and see Porges et al. (2013, 2014) for peer-reviewed publications of application of the intervention to children with autism spectrum disorders.]