Pain
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Randomized Controlled Trial Clinical Trial
Effects of TENS frequency, intensity and stimulation site parameter manipulation on pressure pain thresholds in healthy human subjects.
This study evaluated the effects of varying frequency, intensity and stimulation site, of transcutaneous electrical nerve stimulation (TENS) in an experimental model of pain. In a double-blind design 240 volunteers were randomised to one of six experimental TENS groups, a sham TENS or control (n=30 per group; gender balanced). Two TENS frequencies (110 or 4 Hz) and two intensities (strong but comfortable or highest tolerable) at a fixed pulse duration (200 micros) were applied at three sites relative to the measurement site (segmentally, extrasegmentally or a combination of these), for 30 min. Pressure pain thresholds (PPT) were measured using a pressure algometer, in the first dorsal interosseous muscle, every 10 min, during stimulation and for a further 30 min. The high frequency, high intensity segmental, and combined stimulation groups, showed rapid onset and significant hypoalgesic effects. This effect was sustained for 20 min post-stimulation in the high frequency segmental group. All other TENS intervention groups showed hypoalgesic responses similar to the sham TENS group, and none of these groups reached a clinically significant hypoalgesic level. ⋯ The role of TENS frequency, intensity and site are pivotal to achieving optimal hypoalgesic effects, during and after stimulation. Clinical applications of these parameter combinations require further investigations.
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Comparative Study
Gender and laterality differences in thermosensation throughout the perceptible range.
Several studies suggest that females exhibit greater sensitivity to experimentally induced thermal pain than males. These investigations have focused mainly on the sensory-discriminative rather than the affective aspect of pain. Moreover, potential gender differences for the affective components of innocuous thermal sensations have yet to be examined. ⋯ Ratings of unpleasantness also tended to be higher for the left vs. right hand, but this difference fell just short of statistical significance (P=0.06). These findings indicate that sex differences in thermosensory perception are not general, but occur only for the painful and affective components. Of particular note is the sex difference for affective but not intensive ratings of innocuous temperatures, revealing sex differences in thermal perception outside the nociceptive system.
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The etiology and prognosis of chronic daily headache (CDH) are not well understood. The aim of this study is to describe factors that predict CDH onset or remission in an adult population. Potential cases (180+ headaches per year, n=1134) and controls (two to 104 headaches per year, n=798) were interviewed two times over an average 11 months of follow-up. ⋯ A better prognosis was associated with higher education, non-white race, being married, and with diagnosed diabetes. Individuals with less than a high-school education, whites, and those who were previously married had a higher risk of CDH at baseline and reduced likelihood of remission at follow-up. New onset CDH was associated with baseline headache frequency and obesity.
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Joint manipulation has long been used for pain relief. However, the underlying mechanisms for manipulation-related pain relief remain largely unexplored. The purpose of the current study was to determine which spinal neurotransmitter receptors mediate manipulation-induced antihyperalgesia. ⋯ NAN-190 also blocked manipulation-induced antihyperalgesia suggesting that effects of methysergide are mediated by 5-HT1A receptor blockade. However, spinal blockade of opioid or GABAA receptors had no effect on manipulation induced-antihyperalgesia. Thus, the antihyperalgesia produced by joint manipulation appears to involve descending inhibitory mechanisms that utilize serotonin and noradrenaline.
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Comparative Study
The parents' postoperative pain measure: replication and extension to 2-6-year-old children.
Pain assessment is a difficult task for parents at home following children's surgery. The purpose of the present study was to confirm the psychometric properties of a behavioural measure of postoperative pain developed to assist parents with pain assessment in children aged 7-12 years following day surgery. The study also examined the reliability and validity of the measure with children aged 2-6 years. ⋯ As global pain ratings decreased from Days 1 to 2, so did scores on the PPPM. Scores on the PPPM were successful in discriminating between children who had undergone low/moderate and high pain surgeries. The results of this study provide evidence of the reliability and validity of the PPPM as a measure of postoperative pain among children aged 2 through to 12 years.