An experimental study of attention, labelling and memory in people suffering from chronic pain.

Cognitive-behavioural approaches to treatment have become an important part of the clinical management of chronic pain. More recent developments in cognitive-behavioural theory, based on recent developments in the understanding and treatment of health anxiety, have emphasized the importance of catastrophizing appraisals, which drive both attentional processes and behavioural responses, which in turn are believed to be crucial for the maintenance of chronic pain. The experiment conducted here investigated the responses of pain patients (n=39) and controls (n=71) to a behavioural task (prolonged squeezing a dynamometer). Subsequently, the impact of a cognitive task, which fully engaged participants' attention (dichotic listening) was examined. Participants were asked, firstly, to sustain an isometric muscle contraction task (squeezing); secondly, to learn an attentional demanding task (dichotic listening); thirdly, to recall the discomfort experienced in the squeezing task and lastly, to perform both squeezing and dichotic listening at the same time. The squeezing tasks were experimentally manipulated by attaching a more or less negative label ("pain tolerance test" vs. "muscle stamina and strength test"). Patients were found to be less able to sustain prolonged muscle tension than controls, but the effect was not evident once the distracting task was introduced; similar effects were found for discomfort. All participants subsequently recalled the squeezing task as being longer and associated with less discomfort than they had actually recorded it at the time. In the dichotic listening tasks, although patients detected the same number of words overall as controls did, they were less able to focus on the target channel (i.e. they detected more of the words included as distractors on the unattended channel).