In addition to these external sensations, this sensory experience would also be accompanied by visceral and affective sensations that evoke emotion (e.g., love). Now, imagine the person greeting you with a handshake was a loved one.

Here, you see the person through visual input, you hear the person’s verbal greeting through auditory input, and you experience the handshake through tactile input. For example, imagine an individual greeting you “hello” with a handshake. A single sensory experience contains various sources of incoming sensory input that require integrative processing. Sensory processing refers to the ability to register, modulate, and organize incoming sensory information from one’s internal and external worlds, and in turn, guides adaptive and goal-oriented behavioral responses to sensory stimuli ( Atick, 1992 Baker et al., 2008 Chun et al., 2011 Gilbert and Sigman, 2007). The ability to interpret sensations from the external world and from within the internal body influences one’s perception, which informs how we navigate and communicate with our surroundings. Finally, we introduce a theoretical neurobiological framework to account for altered sensory processing among traumatized individuals with and without the dissociative subtype of PTSD. We postulate that alterations in the neural pathways important for the processing of sensations originating in the outer and inner worlds may have cascading effects on the performance of higher-order cognitive functions, including emotion regulation, social cognition, and goal-oriented action, thereby shaping the perception of and engagement with the world. Here, we review putative neural alterations that may underlie how sensations are experienced among traumatized individuals with PTSD and its dissociative subtype, including those from the outside world (e.g., touch, auditory, and visual sensations) and the internal world of the body (e.g., visceral sensations, physical sensations associated with feeling states). This presentation includes symptoms of depersonalization and derealization, where individuals may feel as if the world or self is “dream-like” and not real and/or describe “out-of-body” experiences. Approximately 14–30% of traumatized individuals present with the dissociative subtype of PTSD, which is often associated with repeated or childhood trauma. Post-traumatic stress disorder (PTSD) is triggered by an individual experiencing or witnessing a traumatic event, often precipitating persistent flashbacks and severe anxiety that are associated with a fearful and hypervigilant presentation. 7The Brain and Mind Institute, London, ON, Canada.6Imaging Division, Lawson Health Research Institute, London, ON, Canada.5Department of Neuroscience, Western University, London, ON, Canada.4Department of Psychiatry, Western University, London, ON, Canada.Joseph’s Healthcare, Hamilton, ON, Canada 2Homewood Research Institute, Guelph, ON, Canada.

1Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, ON, Canada.

Auditory overload anxiety