Pain research has shown that fear-avoidance beliefs determine disability from back pain to a significant degree. It is assumed that anxiety regarding certain movements or activities motivates avoidance behavior. It has not yet been established whether chronic low back pain (CLBP) patients actually experience fear of movement when confronted with back pain-related movements. Startle response measures reliably differentiate the affective quality of a stimulus. This study investigates whether CLBP patients show a startle response typical for aversive stimuli when confronted with pictures of back pain-related movements.
In 36 patients with CLBP, 18 headache patients and 18 healthy controls, the startle response was examined in the presence of pictures of back pain-related movements (e.g., bending) and pleasant movements (e.g., taking a relaxed position). Back pain patients did not show the predicted startle potentiation when viewing back pain-related pictures, although they rated these pictures as more aversive than did the other two groups. Results may indicate that it is not fear of pain that motivates avoidance behavior and determines disability, but rather an individual’s beliefs and attitudes concerning back stressing movements.