The journal of pain : official journal of the American Pain Society
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Engaged attention, including music listening, has shown mixed results when used as a method for reducing pain. Applying the framework of constructivism, we extend the concept of engagement beyond attention/distraction to include all cognitive and emotional/motivational processes that may be recruited in order to construct an alternative experience to pain and thus reduce pain. Using a music-listening task varying in task demand, we collected stimulus-evoked potentials, pupil dilation, and skin conductance responses to noxious electrocutaneous stimulations as indicators of central and peripheral arousal, respectively. Trait anxiety (Spielberger State-Trait Anxiety Inventory) and absorption (Tellegen Absorption Scale) provided indicators of individual differences. One hundred and fifty-three healthy, normal volunteers participated in a test session in which they received 3 stimulus intensity levels while listening to background tones (No Task) or performing a music-listening task. Linear slopes indicating net engagement (change in stimulus arousal relative to task performance) decreased with increasing task demand and stimulus level for stimulus-evoked potentials. Slopes for pupil dilation response and skin conductance response varied with task demand, anxiety, and absorption, with the largest engagement effect occurring for high anxiety/high absorption participants. Music engagement reduces pain responses, but personality factors like anxiety and absorption modulate the magnitude of effect. ⋯ Engaging in music listening can reduce responses to pain, depending on the person: people who are anxious and can become absorbed in activities easily may find music listening especially effective for relieving pain. Clinicians should consider patients' personality characteristics when recommending behavioral interventions like music listening for pain relief.
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The primary symptom of fibromyalgia (FM) is chronic, widespread pain; however, patients report additional symptoms including decreased concentration and memory. Performance-based deficits are seen mainly in tests of working memory and executive function. Neural correlates of executive function were investigated in 18 FM patients and 14 age-matched healthy controls during a simple Go/No-Go task (response inhibition) while they underwent functional magnetic resonance imaging (fMRI). Performance was not different between FM and healthy control, in either reaction time or accuracy. However, fMRI revealed that FM patients had lower activation in the right premotor cortex, supplementary motor area, midcingulate cortex, putamen and, after controlling for anxiety, in the right insular cortex and right inferior frontal gyrus. A hyperactivation in FM patients was seen in the right inferior temporal gyrus/fusiform gyrus. Despite the same reaction times and accuracy, FM patients show less brain activation in cortical structures in the inhibition network (specifically in areas involved in response selection/motor preparation) and the attention network along with increased activation in brain areas not normally part of the inhibition network. We hypothesize that response inhibition and pain perception may rely on partially overlapping networks, and that in chronic pain patients, resources taken up by pain processing may not be available for executive functioning tasks such as response inhibition. Compensatory cortical plasticity may be required to achieve performance on a par with control groups. ⋯ Neural activation (fMRI) during response inhibition was measured in fibromyalgia patients and controls. FM patients show lower activation in the inhibition and attention networks and increased activation in other areas. Inhibition and pain perception may use overlapping networks: resources taken up by pain processing may be unavailable for other processes.
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In recent years, there has been increasing acknowledgment of the need for psychometric data regarding the dot-probe paradigm. The aim of the present study was to provide some data on the psychometric properties of the dot-probe paradigm in the context of pain-related research. Using the data of a large pain-free sample and a large chronic pain sample, the present study examined the psychometric properties of a picture- and word-based dot-probe task. It also examined the data of idiosyncratically selected stimuli designed to be relevant to each participant and compared this with the data of neutral stimuli and nonsalient pain-related stimuli. Poor levels of internal consistency (α range: -.44 to .28; split-half r range: -.35 to .11) and test-retest reliability (r range: -.14 to .13) were found among the pain-free sample, irrespective of the task used or the stimuli used. There was limited evidence of comparability between the 2 tasks among the chronic pain sample (r range: -.08 to .26) and similarly poor levels of internal-consistency (α range: -.56 to .17; split-half r range: -.20 to .25). The findings of the present study therefore suggest that psychometric issues may be important to pain-related attentional bias research. More research is, however, undoubtedly needed. ⋯ The aim of the present study was to provide data regarding the psychometric properties of the dot-probe paradigm within the specific context of pain-related attentional bias research. The findings of this study suggest that psychometric issues may be an important consideration in pain-related attentional biases research.
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Numerous studies have shown that pain-related fear is one of the strongest predictors of pain disability in patients with chronic musculoskeletal pain, and there is evidence that the reduction of pain-related fear through an exposure treatment can be associated with restoration of functional abilities in patients with complex regional pain syndrome type I (CRPS-I). These findings suggest that pain-related fear may be associated with functional limitations in neuropathic pain as well. The aim of the current study was to test whether the debilitating role of pain-related fear generalizes to patients with CRPS-I. The results of 2 studies are presented. Study I includes a sample of patients with early CRPS-I referred to an outpatient pain clinic. In Study II, patients with chronic CRPS who are members of a patients' association were invited to participate. The results show that in early CRPS-I, pain severity but not fear of movement/(re)injury as measured with the Tampa Scale for Kinesiophobia was related to functional limitations. In patients with chronic CRPS-I, however, perceived harmfulness of activities as measured with the pictorial assessment method significantly predicted functional limitations beyond and above the contribution of pain severity. Not fear of movement/(re)injury in general, but the perceived harmfulness of activities appears a key factor that might be addressed more systematically in the clinical assessment of patients with CRPS-I. These results support the idea that pain-related fear might be a promising concept in the understanding of pain disability in patients with neuropathic pain. ⋯ This is the first study showing that perceived harmfulness of activities contribute to the functional limitations in CRPS-I. The current findings may help clinicians customizing cognitive-behavioral treatments for patients with chronic neuropathic pain.
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The aim of this study was to evaluate motor unit activity from a latent myofascial trigger point (MTP) in an antagonist muscle during isometric agonist muscle contraction. Intramuscular activity was recorded with an intramuscular electromyographic (EMG) needle inserted into a latent MTP or a non-MTP in the posterior deltoid muscle at rest and during isometric shoulder flexion performed at 25% of maximum voluntary contraction in 14 healthy subjects. Surface EMGs were recorded from the anterior and posterior deltoid muscles. Maximal pain intensity and referred pain induced by EMG needle insertion were recorded on a visual analogue scale. The results showed that higher local pain was observed following needle insertion into latent MTPs (4.64 ± .48 cm) than non-MTPs (2.35 ± .43 cm, P < .005). Referred pain was reported in 6/14 subjects following needle insertion into latent MTPs, but none into the non-MTPs. The intramuscular EMG activity, but not surface EMG activity, in the antagonist muscle was significantly higher at rest and during shoulder flexion at latent MTPs than non-MTPs (P < .05). The current study provides the first evidence that increased motor unit excitability is associated with reduced antagonist reciprocal inhibition. ⋯ This study shows that MTPs are associated with reduced efficiency of reciprocal linhibition, which may contribute to the delayed and incomplete muscle relaxation following exercise, disordered fine movement control, and unbalanced muscle activation. Elimination of latent MTPs and/or prevention of latent MTPs from becoming active may improve motor functions.