European journal of pain : EJP
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Whiplash injury and chronic whiplash syndrome represent major health problems in certain western communities, pain being the main symptom. Sensitization of the nociceptive system may play a role for non-recovery after whiplash injury. ⋯ This study examined if tolerance to endure pain stimuli may predict outcome in whiplash injury. In a prospective fashion, 141 acute whiplash patients exposed to rear-end car collision (WAD grade 1-3) and 40 ankle-injured controls were followed and exposed to a cold pressor test, respectively, 1 week, 1, 3, 6 and 12 months after the injury. VAS score of pain and discomfort was obtained before, during and after immersion of the dominant hand into cold water for 2 min. The McGill Pain Questionnaire showed that ankle-injured controls had higher initial pain scores than the corresponding whiplash group, while whiplash-injured subjects had higher scores at 6 months; pain scores being similar at other time points. No difference was found in cold pressor pain between recovered whiplash patients and ankle-injured subjects. Non-recovery was only encountered in whiplash injury. Eleven non-recovered whiplash patients (defined as: handicap after 1 year) showed reduced time to peak pain from 1 week to 3 months (P<0.001), 6 months (P<0.01), but not 12 months after the injury. A larger pain area was seen in non-recovered vs. recovered whiplash-injured subjects during the entire observation period (P<0.001). Non-recovery after whiplash was associated with initially reduced cold pressor pain endurance and increased peak pain, suggesting that dysfunction of central pain modulating control systems plays a role in chronic pain after acute whiplash injury.
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Comparative Study
Comparing acceptance- and control-based coping instructions on the cold-pressor pain experiences of healthy men and women.
The current study reflects recent developments in psychotherapy by examining the effect of acceptance-based coping instructions, when compared to the opposite, more control/distraction-based instructions, on cold-pressor pain. Since previous research indicates gender differences in how people cope with pain, we also sought to determine whether differences would be found between healthy men and women. ⋯ Finally, for affective pain, acceptance instructions only benefited women. These results suggest that acceptance-based coping may be particular useful in moderating the way in which individuals, especially women, cope with pain.
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Needle stimulation (acupuncture) has recently been shown to increase blood flow in the tibialis anterior muscle and overlying skin in healthy subjects (HS) and patients with fibromyalgia (FM). The aim of the present study was to examine the effect of needle stimulation on local blood flow in the trapezius muscle and overlying skin in HS and two groups of patients suffering from chronic pain in the trapezius muscle, i.e., FM and work-related trapezius myalgia (TM) patients. Two modes of needling, deep muscle stimulation (Deep) and subcutaneous needle insertion (SC), were performed at the upper part of the shoulder and blood flow was monitored for 60 min post-stimulation. ⋯ Positive correlations were found between muscle blood flow at Deep and pressure pain threshold in the trapezius muscle, neck movement and pain experienced at the stimulation, and negative correlations were found with spontaneous pain-related variables, symptom duration and age, pointing to less favorable results with worsening of symptoms, and to the importance of nociceptor activation in blood flow increase. It was hypothesized that the different patterns of muscle blood flow response to the needling may mirror a state of increased sympathetic activity and a generalized hypersensitivity in the patients. The intensity of stimulation should be taken into consideration when applying local needle stimulation (acupuncture) in order to increase the trapezius muscle blood flow in chronic pain conditions.
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Pain is more common in multiple sclerosis (MS) than has previously been recognised. In the present study we have investigated the occurrence of central pain (CP) in MS and defined its characteristics. Questionnaires were sent to all 429 patients with definite MS in the patient register at our neurology department. ⋯ Trigeminal neuralgia in MS started later in life and after longer disease duration than non-trigeminal pain. Both types of CP existed either chronically or as a feature of relapse. Central pain is thus an important symptom in MS (around 30%) and causes much suffering.
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The present study examined the influence of innocuous skin cooling on the perception and neurophysiological correlates of brief noxious CO2 laser stimuli. In nine normal subjects, brief CO2 laser pulses of four different intensities (duration 50 ms; diameter 5 mm; intensity range 5.8-10.6 mJ/mm2) were delivered at random every 5-10 s on the dorsum of the hand. Innocuous skin cooling was performed by a thermode (20 degrees C; 3x3 cm) with a central hole for the laser test stimuli. ⋯ Reaction times were delayed. The late-LEPs, correlates of Adelta-nociceptor activations, were also significantly depressed while the ultra-late LEPs, correlates of C-nociceptors, were not affected. Taken together, these results strongly suggest that innocuous skin cooling interfered with the sensory processing of laser heat stimuli and more prominently with those related to Adelta-nociceptive input.