(324) Pain-related fear: one or many?

Pain-related fear (PRF) is considered important for pain chronification and disability (Vlaeyen, 1996). Several scales are used to assess PRF, including the Tampa Scale for Kinesiophobia (TSK) and the Fear Avoidance Belief Questionnaire (FABQ). However, Lundberg et al. (2011) concluded that “[…] the weak construct validity (of PRF questionnaires) implies that no measure can […] identify who is fearful.” We reasoned that different PFR constructs should be associated with distinguishable neural patterns during relevant brain activity. Brain activation was recorded using functional magnetic resonance imaging while 20 non-specific chronic low back pain patients viewed videos of activities potentially harmful for the back. PRF was assessed using the 17-item TSK and the FABQ (German versions). Multi-variate pattern analysis (MPVA) was used to determine whether different activity patterns within the fear network related to individuals' TSK and FABQ scores. MPVA (PRoNTo) of the individual beta images (SPM 12) was performed with the TSK and FABQ scores as regression targets. Two separate feature sets were defined (I: bilateral amygdalae II: a NeuroSynth forward-inference mask based on the term ‘fear’). Pattern decoding performance was defined on r2-values significance determined by a null distribution (1000 permutations). TSK and FABQ scores were not correlated in our sample, although both are used to measure PRF. Supporting the notion that they assess different PRF constructs, MVPA results differed for the two questionnaires. A significant multivariate pattern across the fear network (r2 = 0.37, p = 0.01) predicted TSK scores, whereas the amygdala pattern predicted FABQ scores (r2 = 0.31, p = 0.04). These results indicate that two different PRF measures, specifically the TSK and the FABQ, are related to different activation patterns within fear-processing regions, suggesting that these two measures of PRF are not inter-changeable. Future studies should aim at differentiating health outcomes associated with individual PRF measures.