Defence response mobilization in response to provocation or imagery of interoceptive sensations in adolescents with chronic pain: a study protocol

Introduction: Fear of pain seems to be a key factor in the development and maintenance of chronic pain and pain-related disability. Interoceptive fear conditioning is assumed to constitute an important mechanism in the origins and maintenance of fear of pain. If conditioned stimuli such as internal bodily sensations are repeatedly paired with pain (unconditioned stimulus), they in turn elicit a conditioned fear response, including defence mobilization such as startle modulation and changes in heart rate and electrodermal activity. Research into emotional imagery suggests that defensive responses can also be elicited through imagery of fear scripts. Objectives: We present 2 novel paradigms adapted from research on anxiety disorders, which allow to test, if perceived or imagined sensations locally proximal to the main pain location trigger heightened defence response mobilization in adolescents with chronic headaches and abdominal pain. Methods: The provocation paradigm includes the anticipation and provocation of locally proximal and locally distal interoceptive sensations through disorder-specific muscle tensing tasks (tightening the neck or the abdominal muscles). The imagery paradigm includes 3 imagery scripts (standard neutral, standard fear, and disorder-specific). Startle probes are presented in both paradigms. Defence response mobilization is assessed using psychophysiological measures (startle response modulation, skin conductance level, and heart rate), as well as self-reported measures of fear. Perspective: The paradigms will give insight into the defence response of adolescents with chronic pain, when confronted with or imagining interoceptive sensations. Results may inform the improvement of clinical interventions aimed to decrease fear of bodily sensations such as interoceptive exposure or interoceptive imagery exposure.