Cognitive Bias Modification for Interpretation Individuals With Chronic Musculoskeletal Pain

Sensory and emotional pain words from the McGill Pain Questionnaire (MPQ) were presented, grouped as they are on the MPQ. Participants chose one word from each group most representing the pain experienced performing a dynamic arm exercise (rotating their arms in small circles forwards for 10 seconds then backwards for 10 seconds, repeating the process as many times as possible).

Participants rated each word from 0 (not at all representative) to 10 (extremely representative) or indicated if none represented their exercise pain. Emotional response to exercise pain was calculated from intensity and representativeness scores. For intensity, words were assigned a numeric score according to MPQ instructions and summed for emotional and sensory words. For representativeness, mean rating of representativeness was calculated for sensory and emotional pain words. The sensory score was subtracted from the emotional score to compute emotional response to pain relative to the sensory experience.

Participants were presented twenty pain-related images, and asked to rate the extent to which they felt negative emotions while viewing the image. After a fixation cross presented for 500 ms, a pain-related picture was presented for 6000 ms. This was followed by another cross presented for 500 ms then numbers from 0 (not at all negative) to 10 (very negative) was displayed. Participants were instructed to look at the picture on the screen then to rate their negative emotion from 0 (not at all negative) to 10 (very negative). The mean rating of emotional response to pain-related images was calculated for each participant.

Fear of Pain Questionnaire - III. A 30-item scale (0 - Not at all, to 5 - Extreme), including three subscales: major pain (e.g., a car accident), minor pain (e.g. biting your tongue), and medical pain (e.g. an injection), with 10 items in each subscale. Higher scores indicate higher levels of pain-related fear.

Anxiety subscale of the Hospital Anxiety and Depression Scale (HADS). A seven-item subscale of the 14-item HADS (ranging from 0 - 3, or 3 - 0), with higher scores indicating higher levels of anxiety.

Depression subscale of the Hospital Anxiety and Depression Scale (HADS). A seven-item subscale of the 14-item HADS (ranging from 0 - 3, or 3 - 0), with higher scores indicating higher levels of depression.

Sensory and emotional pain words from the McGill Pain Questionnaire (MPQ) were presented, grouped as they are on the MPQ. Participants chose one word from each group that was most representative of their average experience of clinical musculoskeletal pain. Participants rated each word on a scale from 0 (not at all representative) to 10 (extremely representative), or indicated if none of the words were representative of their pain. Indices of emotional response to musculoskeletal pain were calculated from intensity and representativeness scores. For intensity, words were assigned a numeric score according to the MPQ scoring instructions and these were summed for emotional and sensory words separately. For representativeness, the mean rating of representativeness was calculated for sensory and affective/evaluative (emotional) pain words separately. The sensory score was subtracted from the emotional score to determine the emotional response to pain relative to the sensory experience.

Pain severity subscale of the Brief Pain Inventory - Short Form, assessing pain at its worst and least in the last 24 hours, on average, and right now on a scale of 0 (no pain) to 10 (pain as bad as you can imagine).

Pain interference subscale of the Brief Pain Inventory - Short Form. A seven-item subscale which assesses the extent to which pain has interfered with general activity, mood, walking ability, normal work, relations with other people, sleep, and enjoyment of life over the past 24 hours on a scale of 0 (does not interfere) to 10 (completely interferes).

Assessed via Ambiguous Scenarios Task. The training phase presents ambiguous scenarios with a fragment of the last word shown, which participants completed. In the pain-related modification condition, the final word gave the scenario a pain-related meaning. In the benign modification condition, the final word gave the scenario a neutral meaning. The test phase assesses whether participants interpret new ambiguous scenarios as pain-related or benign, with participants rating the similarity of four endings (two pain-related and two neutral) to the original scenario from 1 (very different in meaning) to 4 (very similar in meaning). The mean score for benign target endings was subtracted from the mean score for negative endings to give an index of interpretation bias (a positive index indicates pain-related interpretation bias). To assess visual imagery, participants rated how easily they could imagine themselves as the protagonist in the scenarios from 1 (not at all) to 5 (extremely).