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Polyvagal Theory ISSUE QUICK BYTES 48 TRAUMA NETWORK FOR CHILDREN Part 1: Polyvagal Theory Brought to you by the PTSS team (KKH) • April 2021 (This article is the first in a three-part series about Polyvagal theory and its clinical applications in trauma intervention.) It is commonly known that our Autonomic Nervous system has two main branches - the Sympathetic Nervous System (SNS) that oversees our fight and flight responses in response to threat in the environment, and What is the the Parasympathetic Nervous System (PNS) that helps our body regulate vagus nerve? to homeostasis after the threat has passed (i.e., Rest/digest). However, The vagus nerve is through his research about the nervous system, Dr Stephen Porges’ the 10th cranial (2018) suggests that our nervous system’s response to safety and threat is nerve that connects more complicated and nuanced than that. According to Polyvagal theory the brain stem to (Porges, 2009), in addition to the fight or flight response (i.e., organs in the neck, Mobilisation) of the SNS, there are two other pathways within the chest and abdomen. parasympathetic branch, that are found in the vagus nerve: the Ventral Vagus and the Dorsal Vagus. Let’s take a look at when these different systems are engaged and how our responses to threat may differ accordingly. The Polyvagal Ladder: A Tiered Response to Threat Our nervous system is constantly receiving and reacting to cues of safety or danger in the environment, and these reactions can happen without conscious awareness (a process that Porges coined as Neuroception). There are three types of cues (Dana, 2018): 1. Internal (e.g., body sensations, feelings, thoughts) 2. External (e.g., things in the environment like being overworked, seeing a trauma reminder) 3. Between (e.g., relational factors like acceptance, being shamed or rejected by others) The nervous system responds to these cues by moving us through these three states to protect us: Social Engagement, Mobilisation, and Immobilisation. An analogy used to describe these state shifts is the Polyvagal Ladder (Dana, 2018), where safety cues bring us up the ladder, and danger cues down the ladder. Ventral Vagus System (Top of the ladder) When the environment is safe, our ventral vagus system is engaged, and we are biologically wired to connect with people. This is a state where we feel safe, calm, present, and ready to communicate with others. Physiologically, our heart rate is slower, breathing is regular, muscles are relaxed, our vocal tone has more prosody, and our ears are tuned to human voices. At the first sense of danger or cues signalling danger, our nervous system will first try to re-establish a sense of safety by engaging and connecting with others. For example, if something goes wrong at home or at work, we often first ask family members or colleagues for help. We see this behaviour in children as well, who might seek out a caregiver the moment they are uncertain about something in their environment. Sympathetic Nervous System (Middle of the ladder) If our brain picks up more cues of danger in the environment, our body slides down a step in the ladder by engaging the sympathetic nervous system and activating a state of mobilisation (fight or flight). We may feel anxious, worried, panicked, or angry. Our heart rate and breathing increase, digestion slows down, muscles are braced for action, so that our body has energy to run away or fight back. We are not ready to reason through or talk about our emotions. For example, if a child perceives a threat in the environment and is not able to get reassurance from adults around, they may become clingy, cry, or shout. Dorsal Vagus System (Bottom of the ladder) When the danger is ongoing or extreme and we are not able to escape from it, we slip from the state of mobilisation down to the bottom of the ladder. Our Dorsal Vagus system is activated which brings our body into a state of immobilisation (i.e. shut down). In this state, we may feel numb, shame, hopeless, frozen, or disconnected. Physiologically, our heart rate slows down, blood pressure and body temperature drops, pain tolerance increases, and movements are slower. We disconnect from others and the present moment, are even less able to communicate, and our memory tends to be fragmented or hazy. This state is our nervous system’s way of giving us another chance to survive a dangerous situation (just like how certain animals play dead to avoid a predator). Trauma and Neuroception When an individual is exposed to trauma, their brains and bodies learn to associate danger with cues related to the threatening event, and their nervous systems then activates the mobilisation and/or immobilisation pathways. As the individual learns to differentiate between the danger in the past, and cues in the present, so too does the brain; it learns that it no longer needs to activate the nervous system for survival in response to these cues. For children who are exposed to chronic or multiple traumatic events, their brains adapt by strengthening the neural pathways for mobilisation and/or immobilisation, so that these pathways can be activated as quickly as possible for survival and protection. These adaptations, while helpful in moments of actual danger, may create other challenges for the child when their nervous systems continue to activate these pathways indiscriminately out of an abundance of caution, in response to cues that may not actually be dangerous (i.e., their window of tolerance narrows). In addition, because they spend so much time in the two bottom pathways (refer to ladder diagram), their bodies become less efficient at returning them back up the polyvagal ladder to the regulated, socially connected state of the Ventral Vagal system. Not only do they react stronger and faster to seemingly “minor” stressors or nonthreatening cues, they may also take longer to calm down. All hope is not lost though, as neuroscience also tells us that we can help clients, and ourselves, to notice what state our nervous systems are in and take steps to create state changes towards social engagement. In the next few articles, we will explore various strategies to regulate the nervous system using bottom-up and top-down approaches. References: Dana, D. (2018). The Polyvagal Theory in Therapy: Engaging the Rhythm of Regulation. W. W. Norton & Company, Inc. Porges, S. W. (2009) The Polyvagal Theory: New insights into adaptive reactions of the autonomic nervous system. Cleveland Clinic Journal of Medicine, 76(4), 86-89. https://doi.org/10.3949/ccjm.76.s2.17 Porges, S. W., & Dana, D. (2018). Clinical Applications of the Polyvagal Theory: The Emergence of Polyvagal Informed Therapies. W.W. Norton &Company Ltd. The Trauma Network for Children (TNC) programme is a joint collaboration between KK Women’s and Children’s Hospital (KKH) and Temasek Foundation. It aims to enhance the capability of the Singapore community in providing psychosocial support to children, youth and their families after crises or traumatic events..
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