Articles: pain-threshold.
-
Pressure-pain threshold (PPT) measurements were performed with a pressure algometer, at 22 specified points in the head in patients with cervicogenic headache (n = 32), migraine (with and without aura) (n = 26) and tension-type headache (n = 17). Comparisons were made with a group of healthy controls (n = 20). The average PPT differed significantly between the groups (ANOVA, F = 9.5, P < 0.0005), largely caused by the low threshold in cervicogenic headache patients. ⋯ The ratio between the dominant and non-dominant sides (all 11 points on each side) was 0.85 in cervicogenic headache, whereas it was 0.99 in migraine patients with side preponderance of the pain. The present results support the view that the pathogenesis of cervicogenic headache differs from that of migraine and tension-type headache. The results may further support the theory that fibres from the C2 level (innervating the occipital part of the head) may be included in the pathogenetic mechanism in cervicogenic headache.
-
Pain threshold, nociceptive flexion reflex (NFR) threshold and responses to suprathreshold stimulation were investigated in 15 female patients (mean age 32 yr (range 22-48 yr)) before and 68 (range 48-96) h after gynaecological laparotomy. Control measurements were performed in 17 healthy human volunteers (five males, age 30 yr (range 24-41 yr)). In the surgical patients, pain threshold decreased and pain to suprathreshold stimulation increased significantly (P = 0.006 and P = 0.04, respectively) from before to after surgery. ⋯ The correlations between the relative change in pain and reflex thresholds, and time from surgery, were statistically significant (pain threshold: rs = 0.53, P = 0.04; NFR thresholds: rs = 0.54, P = 0.04). In the healthy volunteers, no significant differences in thresholds and responses to suprathreshold stimulation were observed between two recordings with an interval of at least 48 h. The allodynia and hyperalgesia observed in postsurgical patients may be related to postoperative sensitization of central neurones.
-
The analgesic effects induced by two different kinds of peripheral conditioning stimulations, electroacupuncture (EA) and transcutaneous electrical nerve stimulation (TENS), were compared in the rat using the latency of radiant heat-evoked tail flick reflex as nociceptive index. The parallel elevations of withdrawal latency of tail flick were produced by EA and TENS administrations at the acupoints of S36 and Sp6 with low intensity (1-2-3 mA) and one of three different frequencies (2, 15 and 100 Hz). Analgesic effects of EA or TENS were characterized by slow-on and slow-off nature, and a significant linear correlation was found between both at any one of three frequencies. ⋯ Tolerance to EA stimulation with one of three frequencies reduced the corresponding frequency TENS-induced analgesia and vice versa. These data indicate that: (a) there is no significant difference in producing antinociception for two different peripheral conditioning stimulations when applied at the same sites and (b) the common neural mechanisms most likely process the analgesic effects of EA and TENS. The involvement of (an) endogenous opiate mechanism in the management of different frequency EA and TENS analgesia is discussed in detail.
-
Using a new electronic algometer, the mean values and standard deviations of pressure pain threshold and the intrarater and interrater reliability were evaluated on 13 muscles of the human head and neck region. The subjects were 40 healthy individuals, 21 females and 19 males. ⋯ Statistically significant correlation coefficients were obtained from the values of intra-examiners and inter-examiners in all muscles except the medial pterygoid and middle sternocleidomastoid muscle in male subjects (p < 0.05). This study showed that the electronic algometer could be recommended for evaluation of the pressure pain threshold of human head and neck muscles in clinical and experimental studies.
-
A series of studies with humans as well as experiments carried out on animals have shown that physical exercise leads to temporary hypoalgesia. Reduced sensitivity to pain is not only demonstrable after long-distance exercise (such as a marathon run) but also during and after intensive physical exercise on a laboratory ergometer. In a double blind study (20 mg naloxone versus placebo) experimental pain thresholds (electrical intracutaneous finger and dental pulp stimulation) and plasma hormone levels (beta-endorphin, cortisol, and catecholamines) were measured in ten healthy athletic men before, during, and after physical exercise on a cycle ergometer. ⋯ Central pain inhibitory systems are probably thereby activated by the stimulation of afferent nerves endings (group III and IV) in the skeletal muscle. The same trigger mechanism also plays a role as a release stimulus for hormones which are secreted in increased measure during physical exercise (catecholamines, pituitary hormones). Plasma beta-endorphin is probably not directly involved in the exercise-induced hypoalgesia but is rather a "marker" for the activating of central analgesia mechanisms.