Pain
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Randomized Controlled Trial
Psychophysical study of the effects of topical application of menthol in healthy volunteers.
Cold hyperalgesia is a major clinical phenomenon, but validated experimental models are still lacking for humans. Topical menthol application has recently been proposed as a possible model for the study of cold pain. We characterized the psychophysical effects of 30% l-menthol in ethanol on glabrous skin in 39 healthy subjects, using a double-blind, randomized, crossover design, with ethanol as a control. ⋯ No subject displayed signs of skin irritation or redness. These data suggest that 30% menthol application may be a useful experimental model for studies of cold hyperalgesia in humans. The absence of local skin reactions also makes this test potentially suitable for use in patients.
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Randomized Controlled Trial
Effects of intensity of electroacupuncture upon experimental pain in healthy human volunteers: a randomized, double-blind, placebo-controlled study.
Electroacupuncture is commonly used for pain relief. Despite an extensive evidence-base guiding the selection of stimulation parameters, little methodologically robust research exists regarding the level of intensity required to provide effective doses. This study investigated the hypoalgesic effects of two stimulation intensities compared to placebo on pressure pain thresholds (PPTs) in pain-free humans. ⋯ The control group displayed stable PPT readings over time. No significant differences were observed between the placebo and control groups. These findings suggest that high-intensity levels may be important in optimal dose selection.
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Controlled Clinical Trial
Opioidergic activation in the medial pain system after heat pain.
Opioids modulate the affective component of pain and in vivo data indicate that opioids induce activation changes in the rostral ACC, insula and other brain areas. Hence, opioidergic release is to be expected in these brain regions following experimental pain stimulation. ⋯ Pain stimulation led to significant reduction of diprenorphine binding in limbic and paralimbic brain areas including the rostral ACC and insula. The finding of altered opioidergic receptor availability in the rostral ACC after experimental nociceptive pain is novel and provides direct evidence for the involvement of this region in endogenous opioidergic inhibition of pain.
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Randomized Controlled Trial
Predictive factors for 1-year and 5-year outcome for disability in a working population of patients with low back pain treated in primary care.
Many patients seeking primary care for low back pain continue to report disability several years after their initial visit. The aims of this study were to assess the independent predictive value of a number of potential predictive factors for disability at the 1-year and 5-year follow-ups, and to examine whether prediction models were improved by replacing baseline health-state-related variables with corresponding variables after treatment. A further aim was to describe possible differences between those on sick leave, early retirement or disability pension, and those who were not. ⋯ For those without disability the corresponding figure was 9% (n=8/92). Being a woman, duration of the current episode, similar problems during the previous 5 years, exercise level before the current episode, pain frequency at baseline, and disability after treatment emerged as predictive factors for disability at the 5-year follow-up. Replacing baseline health-state-related measures with corresponding measures after the treatment period, and adding physical-activity-related and possibly work-related factors might improve the likelihood of predicting future disability.
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Randomized Controlled Trial
Parent attention versus distraction: impact on symptom complaints by children with and without chronic functional abdominal pain.
The objective of this study was to assess the impact of parent attention and distraction on symptom complaints by children with and without chronic functional abdominal pain. The water load symptom provocation task was used to induce visceral discomfort in pediatric patients with abdominal pain (N=104) and well children (N=119), ages 8-16 years. Parents were randomly assigned and trained to interact with their children according to one of three conditions: Attention, Distraction, or No Instruction. ⋯ Parents of pain patients rated distraction as having greater potential negative impact on their children than attention. Parents' responses to children's symptom complaints can significantly increase or decrease those complaints. Girls with functional abdominal pain are particularly vulnerable to the symptom-reinforcing effects of parental attention.