Is pain-related fear a predictor of somatosensory hypervigilance in chronic low back pain patients?

Pain-related fear has been found to be associated with increased disability and increased pain perception in patients with chronic low back pain. A po ssible mechanism by which pain-related fear could lead to increased pain pe rception is heightened attention to somatosensory sensations. In the presen t study, chronic pain patients reporting either a high or low level of pain related fear and control participants performed an auditory reaction time task, while occasionally non-painful electrical stimuli - accompanied by th reatening instructions - were given to the arm or back. In the primary task condition, participants had to perform the auditory task while ignoring th e electrical stimuli. Next, the task was presented under dual task conditio ns in which participants had to respond both to tones as well as to detecti on of electrical stimuli. It was hypothesized that for the primary task, hi gh fearful patients would show greater disruption of performance on the aud itory task than low fearful patients and controls when stimuli were present ed to the back. For the dual task, slower reaction times for the auditory t ask, in combination with faster detection of electrical stimuli was expecte d. The hypotheses were not confirmed but patients scoring high on pain-rela ted fear did show an overall increase in reaction time for all conditions o f the primary task, with or without simultaneous stimulation. Regression an alyses demonstrated that high pain-related fear was associated with increas ed reaction time to tones both in patients and healthy controls, and that w ithin patients pain-related fear was a better predictor of reaction time to tones than present pain intensity. The findings may be interpreted as show ing that patients with elevated levels of pain-related fear habitually atte nd to somatic sensations, giving less priority to other attention-demanding tasks. (C) 2001 Elsevier Science Ltd. All rights reserved.