Pain
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Multicenter Study
Determining behavioural and physiological responses to pain in infants at risk for neurological impairment.
Multiple researchers have validated indicators and measures of infant pain. However, infants at risk for neurologic impairment (NI) have been under studied. Therefore, whether their pain responses are similar to those of other infants is unknown. ⋯ A significant Phase effect for low/high frequency Heart Rate Variability (HRV) ratio (F(2,216)=4.97, p=0.008) was found with the greatest decrease in Cohort A. Significant Cohort by Phase interactions existed for low and high frequency HRV. All infants responded to the most painful phase of the heel lance; however, infants at moderate and highest risk for NI exhibited decreased responses in some indicators.
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Review Meta Analysis Comparative Study
Systematic review of observational (behavioral) measures of pain for children and adolescents aged 3 to 18 years.
Observational (behavioral) scales of pain for children aged 3 to 18 years were systematically reviewed to identify those recommended as outcome measures in clinical trials. This review was commissioned by the Pediatric Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (www.immpact.org). In an extensive literature search, 20 observational pain scales were identified for review including behavior checklists, behavior rating scales, and global rating scales. ⋯ No observational measures were recommended for assessing chronic or recurrent pain because the overt behavioral signs of chronic pain tend to habituate or dissipate as time passes, making them difficult to observe reliably. In conclusion, no single observational measure is broadly recommended for pain assessment across all contexts. Directions for further research and scale development are offered.
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Randomized Controlled Trial
Analgesic action of gabapentin on chronic pain in the masticatory muscles: a randomized controlled trial.
Chronic masticatory myalgia (CMM) can be defined as constant pain in the masticatory muscles for more than 6 months and is influenced by the central nervous system. The antiepileptic agent gabapentin acts centrally and is used for managing different types of chronic pain conditions. The objective of this study was to evaluate the analgesic action of gabapentin on CMM. ⋯ Thirty-six patients completed the study. Gabapentin showed to be clinically and statistically superior to placebo in reducing pain reported by patients (gabapentin=51.04%; placebo=24.30%; P=0.037), masticatory muscle hyperalgesia (gabapentin=67.03%; placebo=14.37%; P=0.001) and impact of CMM on daily functioning (gabapentin=57.70%; placebo=16.92%; P=0.022). It can be concluded from this study that gabapentin is effective for the management of CMM.
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Controlled Clinical Trial
Placebo analgesia is accompanied by large reductions in pain-related brain activity in irritable bowel syndrome patients.
Previous experiments found that placebos produced small decreases in neural activity of pain-related areas of the brain, yet decreases were only statistically significant after termination of stimuli and in proximity to when subjects rated them. These changes could reflect report bias rather than analgesia. This functional magnetic resonance imaging (fMRI) study examined whether placebo analgesia is accompanied by reductions in neural activity in pain-related areas of the brain during the time of stimulation. ⋯ Large reductions in pain and in brain activation within pain-related regions (thalamus, somatosensory cortices, insula, and anterior cingulate cortex) occurred during the placebo condition. Results indicate that decreases in activity were related to placebo suggestion and a second factor (habituation/attention/conditioning). Although many factors influence placebo analgesia, it is accompanied by reduction in pain processing within the brain in clinically relevant conditions.
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Biopsychosocial models of chronic pain that recognize psychological and environmental factors as important aspects of adjustment to pain have been proposed for understanding chronic pain and related suffering in persons with multiple sclerosis (MS), but such models have not been empirically tested. The objective of this study was to test such a model by evaluating the associations of several psychosocial variables (i.e., pain-related catastrophizing, perceived social support, pain beliefs, and pain coping) with pain intensity, pain interference with functioning, and psychological functioning in persons with chronic pain and MS, after controlling for demographic and disease-related factors. Participants were 125 community-dwelling persons with MS and pain who completed a mailed questionnaire that included measures of pain intensity and interference, psychological functioning, catastrophizing, social support, and pain beliefs and coping. ⋯ These variables explained an additional 22% of the variance in pain-related interference (p<.001) and 43% of the variance in psychological functioning (p<.001), after adjusting for demographic and MS-related variables and average pain intensity. Catastrophizing was consistently and independently associated with all criterion measures, whereas social support, pain beliefs, and pain coping were associated with some criterion measures but not others. The results provide empirical support for a biopsychosocial understanding of chronic pain in MS and suggest that specific psychosocial factors (e.g., catastrophizing) may be important regarding adjustment to pain in persons with MS.