Impact of Chronic Somatoform and Osteoarthritis Pain on Conscious and Preconscious Cognitive Processing

The study investigates the impact of chronic pain (CP) on conscious and preconscious cognitive processes and on guessing behavior and examines the mediating effect of a depressive state. Twenty-eight patients with CP due to hip osteoarthritis, 32 patients with a somatoform disorder including pain symptoms, and 31 participants who did not have CP were examined within the framework of a modified process-dissociation-paradigm. Neutral, health-threatening, and general threatening stimuli were presented acoustically in a lexical decision task. Parameters of conscious processing, preconscious processing, and of chance were estimated by a multinomial modeling procedure. CP patients with osteoarthritis showed the lowest level of conscious processing and the highest level of guessing behavior. Patients with somatoform pain tended to react preconsciously to health threatening stimuli but overall showed a profile similar to that of control subjects who did not have CP. The impact of the threatening quality of stimuli on different levels of cognitive processing was weak. Depression did not mediate between the experience of pain and estimates of conscious and preconscious processing. Perspective: The impact of CP on preconscious and conscious cognitive processing depends on types and causes of pain. The experience of CP caused by inflammation or physical damage tends to reduce the probability of conscious processing and to provoke memory biases. CP in the context of a somatoform disorder appears to have less impact on cognitive functions. (C) 2008 by the American Pain Society