Measuring fear of movement/(re)injury in chronic low back pain using implicit measures.

Fear of movement/(re)injury is assumed to contribute to the development and maintenance of chronic low back pain (CLBP) in a subgroup of patients. Studying fear of movement/(re)injury with implicit attitude measures, without the awareness of the patient, might be a valuable addition to self-report questionnaires. The aims of the current study were to investigate whether CLBP patients demonstrate more implicit fear of movement/(re)injury than healthy controls, and whether 2 implicit measures are related to each other, and to an explicit self-report measure of fear of movement/(re)injury. A group of 66 CLBP patients and 30 healthy controls took part in this study. In addition to self-report questionnaires, fear of movement/(re)injury was implicitly assessed by the Extrinsic Affective Simon Task (EAST) and the Go-No-Go-Association Task (GNAT) that aimed to determine the association between back-stressing movements and the evaluation "threatening". On both implicit tasks it was found that neither CLBP patients nor healthy controls demonstrated implicit fear of movement/(re)injury, and that CLBP patients did not differ from healthy controls in their level of implicit fear of movement/(re)injury. In general, no associations were found between the EAST and the GNAT, or between implicitly measured and self-reported fear of movement/(re)injury. One major caveat in drawing inferences from these findings is the poor reliability of these implicit measures. Research towards the psychometric properties of these measures should first be expanded before modifying, and applying, them to more complex domains such as fear of movement/(re)injury.