Interoceptive Exposure In Treatment Of Disabling Fear Of Pain: A Single Case Series

Background. This study investigated the use of Interoceptive Exposure (IE) in treatment of disabling fear of pain using a single-case series design. IE is used in treatment of a variety of problems where body sensations are experienced as threatening. IE was used here as an extension of the Fear Avoidance Model. The main hypotheses were that the intervention will reduce fear of pain and increase activity. Additionally, we expected to see a decrease in pain distress and interference, and increase in acceptance of pain. Method. An ABC multiple baseline single-case series design was used. Eight adults referred to clinical psychology through a Pain Clinic were recruited; seven completed treatment. The intervention comprised: one pain education session, two sessions of training in IE plus selfmonitored home practice twice daily for two weeks. Depending on the length of the baseline the study lasted between six and seven weeks. A nine-item instrument was designed to measure fear of pain, pain distress and interference on a daily basis. Physical activity was measured using wearable activity monitors. Standard outcome measures included: pain anxiety, catastrophising, disability and general anxiety and depression. Results. The intervention resulted in reduced fear of pain in some participants, but not all. Six participants improved on at least one of three measures of fear of pain, with two participants improving on all three measures. For one participant there were no changes in fear of pain. Our strongest finding was that the treatment reduced catastrophising, with five participants making significant reliable improvement. All study participants increased their activity levels following the intervention, but for only four participants was this change meaningful. Additionally, contrary to our hypothesis, reduction in fear of pain did not lead to increase in activity. The intervention had no effect on pain acceptance, disability, nor depression and anxiety.