Pain
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The current study examined the Photograph Series of Daily Activities (PHODA) Scale in a sample of chronic low back pain patients with high and low levels of kinesiophobia (pain-related fear). Thirty-three participants completed a modified version of the PHODA (PHODA-M) that obtained ratings of both anticipated pain and harm. Participants' responses on the PHODA-M were compared to predicted and experienced pain and harm ratings collected during a graded-difficulty reaching task. ⋯ In comparison to low fear participants, high fear participants showed larger correlations between pain expectancies for movements depicted in the PHODA and their ratings of predicted and experienced pain on each movement comprising the reaching task. Additionally, high fear participants showed larger associations between the perceived harmfulness of PHODA activities and predicted and experienced harm ratings in response to the reaching task. Implications for the findings are discussed.
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Area-specific representation of mechanical nociceptive stimuli within SI cortex of squirrel monkeys.
While functional imaging studies in humans have consistently reported activation of primary somatosensory cortex (SI) with painful stimuli, the specific roles of subdivisions of areas 3a, 3b, and 1 within SI during pain perception are largely unknown, particularly in the representation of mechanical evoked pain. In this study, we investigated how modality, location, and intensity of nociceptive stimuli are represented within SI by using high-spatial resolution optical imaging of intrinsic signals in Pentothal-anesthetized squirrel monkeys. Perceptually comparable mechanical nociceptive and innocuous tactile stimuli were delivered by indenting the glabrous skin of the distal finger pads with 0.2 and 2mm diameter probes, respectively. ⋯ However, with innocuous tactile stimulation, mainly areas 3b and 1 exhibited response modulation with different levels of stimulation. In summary, mechanical nociceptive inputs are area-specific and topographically represented within SI. We propose that all areas of SI are implicated in encoding the features of mechanical nociception, where areas 3a and 3b are distinctively involved in coding nociceptive and pressure sensation components of stimulation.
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Direct application of cannabinoids to the medullary dorsal horn (MDH) inhibits lamina V nociceptive neurons. The present study compared the effect of the cannabinoid receptor agonist, WIN 55,212-2 (WIN-2) on the activity of lamina I and lamina V MDH neurons using extracellular single unit recording in anesthetized rats. Activity evoked by a contact thermode was measured before and after local application of WIN-2 (0.5-2.0 microg/microl) to the brainstem. ⋯ In separate experiments, the effect of intrathecal administration of WIN-2 to the MDH on head withdrawal latencies elicited by fast and slow heat ramps applied to the whisker pad was assessed in lightly anesthetized rats. Head withdrawal latencies elicited by slow but not by fast heat stimulation were increased by WIN-2. Taken together, these results emphasize the importance of lamina I neurons in the control of a nociceptive heat-evoked reflex.
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Randomized Controlled Trial
Evaluating the effectiveness of exposure and acceptance strategies to improve functioning and quality of life in longstanding pediatric pain--a randomized controlled trial.
Although several studies have illustrated the effectiveness of cognitive behavior therapy (CBT) on adult pain patients, there are few randomized controlled trials on children and adolescents. There is particularly a need for studies on pediatric patients who are severely disabled by longstanding pain syndromes. Acceptance and Commitment Therapy, as an extension of traditional CBT, focuses on improving functioning and quality of life by increasing the patient's ability to act effectively in concordance with personal values also in the presence of pain and distress. ⋯ When follow-up assessments were included, ACT performed significantly better than MDT on perceived functional ability in relation to pain, pain intensity and to pain-related discomfort (intent-to-treat analyses). At post-treatment, significant differences in favor of the ACT condition were also seen in fear of re/injury or kinesiophobia, pain interference and in quality of life. Thus, results from the present study support previous findings and suggest the effectiveness of this ACT-oriented intervention for pediatric longstanding pain syndromes.