不同年龄妇科患者痛阈测试及其临床意义

采用双盲、前瞻性研究,选择90例妇科择期全麻下子宫肌瘤剔除或子宫全切手术患者,ASA分级Ⅰ或Ⅱ级,按年龄分两组,中青年组（A组）50例,年龄25岁～50岁,老年组（B组）40例,年龄60岁-80岁,术前使用电刺激测定并记录患者的痛阈和耐痛阈,观察不同年龄妇科患者痛阈和耐痛阈以及两者之间相关性。结果显示A组与B组痛阈分别为（1．86±0．51）mA和（1．89±0．66）mA差异无统计学意义;A组比B组耐痛阈低分别为（6．16±2．53）mA和（8．40士3．21）mA,差异有统计学意史;A组痛阈与耐痛阈之间有相关性（Spearman相关系数为-0．42,P〈0．05）;B组痛阈与耐痛阈之间无相关性。因此,老年患者耐痛阈升高,中青年患者术前痛阈和耐痛闽均可预测术后疼痛,老年患者术前痛阈不能预测术后疼痛。     

Psychophysical features of the transition from pure heat perception to heat pain perception

The psychophysical features of the transition from the pure heat to the heat pain range were studied in 25 healthy subjects (mean age 28.8 years). Thirty short heat stimuli from ?1.6° C to + 1.6° C relative to the pain threshold were applied to the thenar of the left hand with an apparatus containing a Peltier thermode (nine different temperatures at 0.4°C intervals). The subjects rated the sensation intensity on a visual analogue scale. The resulting stimulus/sensation intensity relations could be explained equally well (same goodness of fit) by a model with a power function (PF) and by a model with two linear regression lines (TLR), one for stimulus intensities below and one for those above the pain threshold and intersecting at the pain threshold. The slopes of the TLR model were significantly larger above the pain threshold than below it. The PF model produced exponents between 1.8 and 1.9. We conclude that to describe the transition area, it is sufficient to use simple linear models for both the pure heat and the heat pain ranges.     

Psychophysical features of the transition from pure heat perception to heat pain perception.

The psychophysical features of the transition from the pure heat to the heat pain range were studied in 25 healthy subjects (mean age 28.8 years). Thirty short heat stimuli from -1.6 degrees C to +1.6 degrees C relative to the pain threshold were applied to the thenar of the left hand with an apparatus containing a Peltier thermode (nine different temperatures at 0.4 degrees C intervals). The subjects rated the sensation intensity on a visual analogue scale. The resulting stimulus/sensation intensity relations could be explained equally well (same goodness of fit) by a model with a power function (PF) and by a model with two linear regression lines (TLR), one for stimulus intensities below and one for those above the pain threshold and intersecting at the pain threshold. The slopes of the TLR model were significantly larger above the pain threshold than below it. The PF model produced exponents between 1.8 and 1.9. We conclude that to describe the transition area, it is sufficient to use simple linear models for both the pure heat and the heat pain ranges.     

Is the Effect of Behavioral Synchrony on Cooperative Behavior Mediated by Pain Threshold?

Synchronized behavior results in a variety of prosocial behaviors. Research has also implicated that interpersonal synchrony affects pain thresholds, inferred as indicative of endorphin levels. The current study was designed to see if these pain threshold effects mediated the effect of synchrony on interpersonal cooperation. Twenty six individuals were randomly assigned to complete a 30 minute run on a treadmill in either a synchronized or nonsynchronized condition. Pain threshold was measured both before and after exercise as an indicator of endorphin activity. A postrun social investment game measured interpersonal cooperation. Analyses showed that there was a significant direct relationship between condition and cooperation but that this effect was not mediated by pain threshold.     

The influence of preferred coping style and cognitive strategy on laboratory-induced pain.

OBJECTIVE: To evaluate the effects of matching an individual's coping style (low, mixed, or high monitoring) to an appropriate cognitive strategy (distraction or sensation monitoring) to improve pain management. DESIGN: This study used a split-plot factorial design in a laboratory setting. MAIN OUTCOME MEASURES: Main outcomes were pain threshold, pain tolerance, pain intensity, pain affect, and anxiety. RESULTS: The results of the 2 x 3 x 3 (Experimental Condition x Coping Style x Trial) analysis of variance (ANOVA) interaction were significant for pain threshold scores, F(4, 178) = 2.95, p < .01. Low monitors in the matched distraction trial had higher pain threshold scores than during baseline, t(15) = -2.68, p = .017, and the mismatched sensation monitoring trial, t(15) = 2.80, p = .014. High monitors' pain threshold scores were higher than baseline only during the matched sensation monitoring trial, t(27) = -2.75, p = .010. The results of the 2 x 3 x 3 ANOVA interaction were not significant for pain tolerance scores; however, when the mixed monitors were excluded, the 3-way interaction was significant, F(2, 124) = 3.48, p < .05. The results were nonsignificant for pain intensity, pain affect, and anxiety. CONCLUSION: Results demonstrate that matching coping style to the appropriate cognitive strategy is important for improving pain threshold and pain tolerance; however, matching did not reduce pain intensity, pain affect, or anxiety. Future studies should explore the explanation for differential responses of high and low monitors and should test these hypotheses in a clinical setting.     

Gender differences in pressure pain threshold in a repeated measures assessment

The objective of this study was to evaluate gender differences in the pain threshold, considering the type of pressure point, its location and the repetition of the assessment. The pressure pain threshold was evaluated in 30 healthy volunteers (12 men and 18 women) in three assessment sessions separated by 15 min and 7 days, respectively. Each assessment session was in turn composed of two trials in each of which 24 different pressure points (symmetrically located), representing the 18 tender points for the diagnosis of fibromyalgia and six control points, were assessed. Gender differences were found in the pain threshold for all of the points and the measures taken, women showing a lower pain threshold in comparison to men and being these differences more pronounced for control points than for tender points, the former reaching statistical significance in all cases. The analysis of the influence of repeated measures on gender differences in the pain threshold showed a distinct pattern of recuperation in men than in women, although only one difference in pain threshold was significant. The utility of the tender point concept to study gender differences in pain threshold and the mechanisms that may explain different patterns of recuperation between genders are discussed.     

The mental pain of the psychoanalyst: A personal view

Abstract

Mental pain is a common concern of psychoanalysts in their professional life. Combining her clinical experience with previous contributions by others, the author presents a personal overview of the patient-triggered mental pain of the analyst. Countertransference is considered to be the major source of the analyst's work-derived mental pain. This type of mental pain is not to be avoided or discarded by the analyst. Rather, the analyst will benefit from tolerating and even welcoming professional mental pain: in most cases, mental pain will bring with it rich clinical material that, upon interpretation, will help him or her to offer previously intolerable contents back to the patient in a transformed version that now becomes acceptable. The analyst's mental pain may emerge in his dreams; clinical examples of this phenomenon are presented. It is suggested that there is an increased chance of the analyst undergoing mental pain when treating patients suffering from severe psychopathology, and a clinical case is reported to illustrate this assertion. The author proposes that a lifelong effort is to be expected from analysts in terms of enhancing their threshold of tolerance to professional mental pain. In situations of mental pain, analysts must be particularly aware of the need to modulate their interpretations before transmitting them to the patient. The capacity of analysts to transform their mental pain (Ta, according to Bion) will depend on the plasticity of their container functions, the quality of their transformation abilities and, in particular, their threshold of tolerance to mental pain.     

Threshold tracking for assessment of long-term adaptation and sensitization in pain perception

To assess temporal variations in the perception of "phasic" heat pain stimuli a psychophysical tracking procedure was developed that enables repeated assessment of the pain threshold at short intervals. This "double-tracking" procedure produces two tracking curves simultaneously, one that approaches the pain threshold gradually from above, the other from below. The threshold for phasic heat pain was measured in 80 tracking trials with stimuli at temperatures near the pain threshold. Concurrently, the threshold for "tonic" heat pain was determined after every 20 tracking trials with a stimulus adjustment procedure. Eleven healthy subjects (age: 26.4 yr. +/- 6.0) participated in 2 sessions each. Phasic stimulation near the pain threshold did not produce any trends in either of the two threshold measures. Hence there was no long-term adaptation or sensitization. However, there were random variations (random walks) in the tracking curves, which we interpret as resulting from a stochastic relationship between stimulus and sensation. In agreement with other reports, discrimination seemed to be better at painful than at nonpainful temperatures.     

A technique for rapid,reliable assessment of thermal-pain threshold in humans

A simple and reliable method of assessing pain threshold in humans may be useful in a number of research areas, such as in examining acute antinociceptive effects of drugs. We have developed a low-cost, computer-controlled method to reliably assess thermal-pain threshold using radiant heat focused from a slide projector and applied to a small area of skin. An electronic shutter is attached to the projector opening to provide precise onset and offset of heat. A computer keypad allows for subject response at the point of pain onset (i.e., threshold), with latency to threshold determined by computer timer. The details of the apparatus setup, subject preparation, and instructions to subjects are presented. The development of the method is described, and sources of unreliability are identified. Coefficients of variation (CVs) are calculated to provide a measure of variability within subjects across trial exposures and across sessions. Results indicate that the method is reliable for determining pain threshold, especially within sessions, and can be employed with relatively minimal expense and subject preparation.     

The influence of stimulus scale-interval upon the assessment of pain threshold

An experiment concerning the influence of the scale of stimulus values upon the perception of heat-pain is reported in which it is found that the value of the threshold stimulus is dependent upon the size of the steps between successive stimuli.

The results are analysed in the light of a paper by Brown and Cane (1959) in which they point out that the value of a sensory threshold yielded by the Limiting Method is mathematically dependent upon the size of the steps between successive values of the variable stimulus. The threshold values reported here are found to be dependent on the step-size between stimuli to a greater extent than that which would be predicted by Brown and Cane.

In view of these results, an attempt is made to explain the wide variety of pain threshold values reported in the literature.     

Shorter articles and notes an optimum interval in the assessment of pain threshold

When the Limiting Method is used to measure heat-pain threshold, the observed threshod has been shown to depend on the size of the stimulus increment used (Haslam, 1965). An experiment is reported here which repeats a finding of the experiment referred to above that the variablility of threshold is relatively large when the stimulus increment is small. A statitistical analysis of the data shows that the previously untested hypothesis that pain threshold is uniform over the population (Hardy, Wolff and Goodell, 1952) is a reasonable one. The psychological implications of threshold variability are discussed in the light of a theoretical model, and a criterion for an optimum interval in the assessment of heat-pain threshold is discussed.     

Pain sensitivity and individual differences in self-reported sexual behavior

The relationship between sexual behavior and pain sensitivity was assessed in 27 heterosexual men and 20 heterosexual women. Sexual behavior measures included sexual motivation and ratings of subjective sexual arousal to and enjoyment of an auditory stimulus. Pain sensitivity measures were pain threshold and pain tolerance in a cold pressor task. Participants were tested after exposure to a neutral or a sexual audio stimulus. Exposure to the sexual stimulus increased pain sensitivity in women but not in men. However, sexual behavior measures were correlated with pain threshold for both men and women. Specifically, higher pain thresholds were associated with weaker sexual motivation, lower enjoyment potential for sexual interaction, and increased inhibition during intercourse. These results are consistent with findings in laboratory animals, suggesting that differences in sexual behavior may reflect differences in responsiveness to a variety of stimuli.     

Active and passive distraction using a head-mounted display helmet: effects on cold pressor pain in children.

OBJECTIVE: The current study tested the effectiveness of interactive versus passive distraction that was delivered via a virtual reality type head-mounted display helmet for children experiencing cold pressor pain. DESIGN: Forty children, aged 5 to 13 years, underwent 1 or 2 baseline cold pressor trials followed by interactive distraction and passive distraction trials in counterbalanced order. MAIN OUTCOME MEASURES: Pain threshold and pain tolerance. RESULTS: Children who experienced either passive or interactive distraction demonstrated significant improvements in both pain tolerance and pain threshold relative to their baseline scores. In contrast, children who underwent a second cold pressor trial without distraction showed no significant improvements in pain tolerance or threshold. CONCLUSION: Although both distraction conditions were effective, the interactive distraction condition was significantly more effective. Implications for the treatment of children's distress during painful medical procedures are discussed.     

Prediction of experimental pain sensitivity by attention to pain-related stimuli in healthy individuals

The aim of the present study was to assess the predictive power of the processing of pain-related information, comprising concepts of hypervigilance to pain, pain catastrophizing, and pain-related anxiety (questionnaires) as well as attentional processes related to pain-related stimuli (dot-probe task) in explaining individual differences in experimental pain sensitivity (pressure/thermal pain threshold). In 160 healthy participants (ages 13-61; 80 females), results of hierarchical multiple regression analyses showed that self-reported hypervigilance contributed significantly to the prediction of pain sensitivity, whereas pain catastrophizing and anxiety did not. However, inconsistent with prediction, the effect was in the opposite direction, indicating that vigilance to pain sensations or stimuli is associated with lower pain sensitivity in healthy individuals. Entering the attentional bias indices from the dot-probe task showed that an increased bias to pain words is related to higher experimental pain sensitivity, which confirms the hypothesis.     

The effect of situation-evoked anxiety and gender on pain report using the cold pressor test

The aims of the present study were to investigate the influence of anxiety on pain perception and to test whether gender differences in pain perception are anxiety dependent. Sixty male and female university students exposed to situation-evoked anxiety or a control procedure were measured for their pain threshold, tolerance, and perceived intensity during a cold pressor test. Both subjective and autonomic responses indicated that anxiety was successfully induced in participants exposed to the anxiety condition. Increased situational anxiety had no significant effect on pain threshold or pain tolerance. Significant increases in pain intensity were found for the anxiety group. Levels of anxiety, however, did not correlate with this increased intensity, raising doubt as to the role of anxiety in producing this effect. No gender differences were found for pain tolerance or pain intensity. Gender differences were found for pain threshold in the anxiety group with, contrary to past findings, females showing significantly higher pain thresholds than males. The results are discussed in the light of related studies.     

PHASE AND SEX EFFECTS IN PAIN PERCEPTION: A CRITICAL REVIEW

The psychological literature in pain perception is reviewed to clarify the influence of sex and menstrual phase on the phenomenon of pain. An attempt is made to resolve some of the discrepancies in the reported findings by taking special note of the methodological differences in the pain studies. The appropriateness of the measures of pain threshold, pain tolerance, discrimination accuracy, and of response bias to the study of pain are discussed.     

Influence of acetaminophen consumption on perceived exertion at the lactate concentration threshold

The purpose of this investigation was to study effects of acetaminophen consumption on ratings of perceived exertion and estimated time limit responses at the lactate threshold. 98 young regional to national level athletes performed a graded exhausting exercise on an outdoor running track to estimate their maximal aerobic velocity and the velocity associated with their lactate concentration threshold. Urine (30 mL) was collected during this test and analysed for numerous substances. During urinary screening for doping substances, 9 acetaminophen consumers (9.2%) among the 98 included athletes were detected. These acetaminophen consumers have significantly lower perceived exertion at velocity corresponding to the lactate concentration threshold than nonconsumers (11.9 +/- 2.1 vs 13.6 +/- 2.1, respectively) although they were at the same relative exercise intensity. This result shows that acetaminophen consumption may have mediated the perceived exertion response at the lactate concentration threshold. This may then suggest that the pain induced by training load could be a factor in use of self-prescribed pain relievers. Such consumption must be taken into account by medical staff, trainers, or educators who have to give information on the use and adverse effects of this substance and to propose palliative methods to their athletes.     

Pain sensitivity and coping strategies among dysmenorrheic women: much ado about nothing

Samples of spasmodic, congestive and combined dysmenorrheic women and non-dysmenorrheic women were subjected to an ischemic pain procedure to measure their pain threshold, pain tolerance and self-reported pain. Cognitive and behavioral strategies that subjects had spontaneously used during the pain procedure were later assessed. A classification system was derived for categorizing subjects' responses to the interview and questionnaire used in this assessment. Contrary to previous claims that dysmenorrheic women may be hypersensitive to pain, no differences in pain sensitivity were discovered among the four groups of subjects. A few differences in cognitive and behavioral strategies did emerge, but these were of insufficient magnitude to contend that dysmenorrheic women are disadvantaged in their strategies for coping with pain.     

Pain perception to the cold pressor test during the menstrual cycle in relation to estrogen levels and a comparison with men.

Animal and human research has shown that pain sensitivity changes during the menstrual cycle. This has sometimes been ascribed to hormonal variations. The aim of the present study was to examine how perception of pain, induced by the cold pressor test to the dominant hand, was related to gender and phases of the menstrual cycle. A repeated-measures design was used, where twenty-two female students participated at two different phases of the menstrual cycle (days 2-4 and days 20-24). A control group of nineteen male students participated on two occasions, separated by a three week period. The cycle phase during which each woman began her participation was randomized. Pain was induced using the cold pressor test. Pain threshold was determined as the duration of time between when the subject first reported pain and exposure to the painful stimulus. Pain tolerance was determined as the duration of time until the subject withdraw her/his hand from the test water because the pain was too intensive. The results showed that men tolerated significantly greater pain than women. Women's pain threshold was significantly higher during the second phase of the menstrual cycle. Systolic pressure was higher in men than women, increasing more in men in response to cold pressor testing than women. Further research, including measurements of plasma hormone levels during the menstrual cycle, is needed to clarify the role played by estrogens in pain perception.     

Relation of skin temperature to pain threshold

Two recent studies have established a very close relationship between environmentally-induced changes in skin temperature and the pain threshold for radiant heat stimuli. The present experiment was designed to verify the relationship by using as pain test area the skin surface of the back of the hand, as the skin temperature here is likely to vary from individual to individual much more than for the forehead.

Subjects were 50 neurotic and depressed patients of both sexes, age range 20-79. Skin temperatures were recorded on the right hand until a steady level was reached, then radiant heat stimuli were applied to a blackened area of the left hand. Results showed a highly significant negative correlation between pain threshold and skin temperature level, while differences due to age and sex were negligible. Drops in skin temperature were a common reaction during pain testing.

The significance of this finding is discussed in terms of the adaptive function of skin temperature changes and their relation to tissue damage. The results are consistent with the view that the pain experience, although having its distinctive sensory components, is intimately related to, and affected by, central factors of autonomic regulation. Some implications for general experimental and clinical research on pain are briefly outlined.