SEARCH · PubMed Health

Results for “Pain Perception”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 739 records · Page 41Linked to original sources

PubMed2004

Effects of distraction on magnetoencephalographic responses ascending through C-fibers in humans.

OBJECTIVE: Using magnetoencephalography (MEG), we evaluated the cerebral regions relating to second pain perception ascending through C-fibers and investigated the effect of distraction on each region. METHODS: Thirteen normal subjects participated in this study. CO2 laser pulses were delivered to the dorsum of the left hand to selectively activate C-fibers. The MEG responses were analyzed using a multi-dipole model. RESULTS: (1) primary somatosensory cortex (SI), and (2) secondary somatosensory cortex (SII)--insula were the main generators for the primary component, 1M, whose mean peak latency was 744 ms. In addition to (1) and (2), (3) cingulate cortex and (4) medial temporal area (MT) were also activated for the subsequent component, 2M, whose mean peak latency was 947 ms. During a mental calculation task (Distraction), all 6 sources were significantly reduced in amplitude, but the SII-insula (P < 0.01) and cingulate cortex (P < 0.001) were more sensitive than the SI (P < 0.05) and MT (P < 0.05). CONCLUSIONS: We confirmed that SI in the contralateral hemisphere and SII-insula, cingulate cortex and MT in bilateral hemispheres play a major role in second pain perception, and all sites were much affected by a change of attention, indicating that these regions are related to the cognitive aspect of second pain perception. SIGNIFICANCE: The SI, SII, cingulate and MT were activated during the C-fiber-related MEG response, and responses in these regions were significantly diminished during mental distraction.

Adult↗

PubMed2001

Involvement of vanilloid receptor VR1 and prostanoids in the acid-induced writhing responses of mice.

We found that intraperitoneal injection of organic acids, such as propionic and lactic acid, are able to develop writhing responses in mice similarly as that of acetic acid. These acid-induced writhing reactions were significantly attenuated by capsazepine, a VR1 receptor-specific antagonist, but the phenylbenzoquinone-induced one was not, suggesting that the acids but not phenylbenzoquinone activate the VR1 receptor, which is involved in polymodal pain perception. Hoe 140, a bradykinin B2 receptor antagonist, also suppressed the acid-induced writhing response. Furthermore, these writhing responses were significantly suppressed after neonatal treatment with capsaicin, which treatment is known to destroy peripheral sensory afferent C-fibers. Capsazepine and Hoe 140 did not further attenuate the already reduced writhing responses of capsaicin-treated mice, suggesting that the acids stimulate the VR1 and the bradykinin B2 receptor in the pathway comprising sensory afferent C-fibers. On the other hand, indomethacin further significantly suppressed the writhing number of the capsaicin-treated animals, suggesting that the acid-induced pain perception requires prostanoid receptors not only in the pathway via capsaicin-sensitive C-fibers but also in other sensory pathways. These results provide the first evidence for the involvement of the vanilloid receptor in the acid-induced inflammatory pain perception via sensory C-fibers in addition to the known mediators bradykinin, neurokinins, and prostanoids.

Acetic Acid↗

PubMed1996

Endogenous beta-endorphins in hypertension: correlation with 24-hour ambulatory blood pressure.

OBJECTIVES: The aims of this study were to determine whether hypertensive patients showed increased endogenous opioid tone and to find a possible correlation between beta-endorphin levels and 24-h ambulatory blood pressure. We also investigated whether circulating beta-endorphin levels were associated with pain perception at rest. BACKGROUND: Experimental studies suggest an involvement of the endogenous opioid system in cardiovascular control mechanisms. METHODS: We determined baseline beta-endorphin plasma levels by radioimmunoassay in 81 consecutive subjects (48 hypertensive, 33 normotensive) after a 30-min rest and before 24-h ambulatory blood pressure monitoring. In 72 of 81 subjects with a dental formula suitable for the pulpar test (graded increase of test current -0 to 0.03 mA applied to three healthy teeth), pain perception was also investigated. RESULTS: Hypertensive patients showed higher beta-endorphin plasma levels than normotensive subjects (p < 0.002). Circulating endogenous opioid levels correlated with 24-h diastolic blood pressure (p < 0.01), whereas the relation with systolic pressure did not reach statistical significance. When 24-h blood pressure recordings were divided into daytime and nighttime values, and blood pressure loads (percent of measurements > or = 140 mm Hg for systolic blood pressure and > or = 90 mm Hg for diastolic pressure) were calculated, a significant correlation was found between beta-endorphin levels and diastolic pressures and load. Similarly, presampling diastolic blood pressure was significantly correlated with beta-endorphin levels. Of the 72 subjects tested, hypertensive patients showed a lower pain sensitivity than normotensive subjects. A positive correlation was found between pain threshold and circulating beta-endorphin levels (p < 0.05). CONCLUSIONS: Sustained arterial pressure is probably involved in the tonic activation of cardiovascular mechanisms linked to endogenous opioid tone. Circulating plasma endorphins may account, at least in part, for the pain perception pattern relating to blood pressure levels at rest.

Adult↗

PubMedDate not supplied

Patients' perception of pain during axillary and humeral blocks using multiple nerve stimulations.

BACKGROUND AND OBJECTIVES: Axillary or humeral blocks by multiple nerve stimulation (MNS) are used for ambulatory hand surgery. This double-blind study identified which of the three main components of the procedure (repeated needle passes, local anesthetic injections, or electrical stimulations) is most painful, quantified its intensity, and recorded patients' preferences for a future anesthetic. METHODS: Eighty unsedated ambulatory patients were randomized to 2 equal groups: axillary (A) and humeral (H). In each patient, 4 terminal motor nerves (musculocutaneous, median, ulnar, and radial) were electrolocated by use of an initial current of 2 mA, 0.1 ms and a target current of 0.1 to 0.5 mA. After block placement and before the start of surgery, patients were requested to identify which of the 3 main components of the block was most unpleasant and to quantify its intensity on a visual analog scale (VAS) of 0 to 100. Twenty minutes after completion of the block, the unblocked nerves were electrolocated at the elbow and supplemented. Patients were declared ready for surgery when they had complete analgesia of the hand and forearm. Before discharge from the hospital, patients indicated which anesthetic method (block alone, block plus sedation, or general anesthesia) they would choose for future hand surgery. RESULTS: Twenty-seven patients in group A vs. 17 patients in group H reported electrical stimulations as the most unpleasant block component (P =.03). No significant differences occurred in any of the VAS scores. Patients' request for the same anesthetic, 35 in group A and 37 in group H, were similar. Group A patients were ready for surgery sooner than group H patients (mean 26 minutes vs. mean 30 minutes for group H patients; P =.04). No serious complications were observed. CONCLUSIONS: This study found that more axillary-block patients compared with humeral-block patients reported electrical stimulation as the most unpleasant part of the block but failed to detect significant differences in the intensity of the 3 block components (repeated needle passes, local anesthetic injections, and electrical stimulations). Most patients in both groups would accept the same block for future hand operations. Patients were ready for surgery sooner after axillary block, but the clinical importance of this finding is doubtful.

Ambulatory Surgical Procedures↗

PubMed2001

Perception of pain coincides with the spatial expansion of electroencephalographic dynamics in human subjects.

The dynamics of cortex driven by painful median nerve stimulation were investigated in event-related oscillation (ERO). We applied a wavelet time-frequency analysis to differentiate the brain dynamics between painful and non-painful somatosensory stimulation. The observed pattern to pain-induced effects exhibited a stepwise decrease of frequencies over time, starting around 26 ms over somatosensory cortex at 80 Hz, intermediate oscillations at 40 and 20 Hz around 40 ms, and reaching down to 10 Hz after 160 ms. This step-wise frequency decrease of ERO, coincident with spatial shift from the contralateral somatosensory area at 80 Hz to the centro-frontal brain at 40/20 Hz and final spatial expansion to the large region of centro-parietal areas at 10 Hz, may represent the cortical processes necessary to transfer sensory information from perceptual stages to subsequent cognitive stages in consciousness.

Adult↗

PubMed2006

Perception of pain following rectal administration of morphine in children: a comparison of a gel and a solution.

BACKGROUND: Rectal administration of morphine is one possible route of delivery in children. The aim of this study was to determine the pain experience during rectal administration of two different morphine preparations. METHODS: The acceptance of the pain of rectal administration of morphine for premedication was studied in 120 children. Children were randomized to receive either morphine solution in saline (0.2 mg.kg(-1), 1 mg.ml(-1)) or morphine gel (0.2 mg.kg(-1), 1 mg.ml(-1)) with an adjusted pH for rectal use in a double-blind fashion. Children were stratified into three groups according to age (1-2, 3-6, and 7-10 years). Pain was assessed with the Children's Hospital of Eastern Ontario Pain Scale, the McGrath Facial Affective Scale, or the visual analogue scale, depending on the age group. RESULTS: The overall pain scores in all age groups were low. Children aged 1-2 years (P < 0.01) and 3-6 years (P < 0.05) had significantly less pain when morphine was administered as a gel than a solution. The difference in pain experience between the two forms was not significant in the age group of 7-10 years. CONCLUSION: The results indicate that most of the children tolerated rectal administration of morphine well in terms of pain experience, in both gel and solution form. The morphine gel, intended for rectal use appears to be the preparation of choice in children aged 1-6 years.

Administration, Rectal↗

PubMed2005

Noninvasive monitoring of diabetes-induced cutaneous nerve fiber loss and hypoalgesia in thy1-YFP transgenic mice.

Progressive loss of pain perception and cutaneous nerve fibers are frequently observed in diabetic patients. We evaluated the feasibility of using thy1-YFP mice that express the yellowish-green fluorescent protein (YFP) in all of their sensory/motor neurons for noninvasive monitoring of cutaneous nerve fiber loss during diabetes. Fluorescent fibers in skin sections from the leg of thy1-YFP mice stained positive for the neuron-specific protein gene product 9.5 (PGP9.5), indicating that the cutaneous fluorescent fibers are indeed nerve fibers. In diabetic thy1-YFP mice, significant small cutaneous nerve fiber loss in the leg was observed at 3 months following the onset of diabetes, but loss of heat-induced pain perception occurred as early as 1 month following the onset of diabetes, indicating that functional impairment of sensory nerves precedes cutaneous nerve fiber loss. Immunostaining of skin sections of mice killed at 6 months following the onset of diabetes showed that parallel to the loss of small fluorescent nerve fibers, there was a significant decrease in fibers stained positive for calcitonin gene-related peptide, substance P, and purinoreceptor subtype in diabetic thy1-YFP mice. These mice will be useful for noninvasive monitoring of cutaneous nerve fiber degeneration and loss of heat-induced pain perception during diabetes and for the assessment of efficacy of therapeutic treatment of diabetic neuropathy.

Animals↗

PubMed2004

A conceptual model of pain assessment for noncommunicative persons with dementia.

PURPOSE: Our objectives are to present a conceptual model of the pain assessment process in persons with dementia and discuss methods for validating our model within this population. DESIGN AND METHODS: This conceptual work is based on an integrative review and current pain theory, pain assessment research in demented and nondemented populations, and research on the science of self-report. RESULTS: We present a multidimensional model of pain assessment that emphasizes the role of the external rater. Our model posits that a nociceptive stimulus leads to pain sensation, followed by pain perception, followed by the exhibition of external signs of pain by the patient, followed by an external rater's observation and interpretation of those external signs. Further, the model specifies the effects of nociceptive stimulus factors on pain sensation; patient-specific factors on pain perception; method-specific factors on external sign observation; and rater-specific factors on external sign interpretation. IMPLICATIONS: Pain assessment in persons with dementia must go beyond a unidimensional model of pain assessment. This multidimensional model also directly addresses the challenges of using external ratings to assess pain in persons with dementia. Finally, we present clinical recommendations for applying the model to pain assessment endeavors and research recommendations for evaluating models of pain in this population.

Dementia↗

PubMed2003

Dressing size and pain: a prospective trial.

BACKGROUND: Pain is a personal, subjective experience. In the postoperative period, pain may be influenced by patient, pharmacological and environmental factors. In surgery the aim is to reduce pain in this period by educating patients and using adequate analgesia. The aim of the present study was to assess the effect of perceived wound size on pain, as indicated by wound dressing, in the immediate postoperative period. METHODS: Patients undergoing appendicectomy were randomized into a group having a dressing the same size (SSD) as the surgical wound or double the size (DSD) of the wound. Patients' pain perception and analgesic requirements were then recorded and analysed to compare the two groups. RESULTS: Both groups had similar results when comparing pain perception. The median total pain score for the SSD and DSD groups at 12 and 24 h postoperatively revealed no statistically significant difference (P > 0.05). CONCLUSION: The data do not support the hypothesis that postoperative pain may be altered by perceived wound dressing size. Dressing size does not appear to be a variable that could easily be altered to reduce postoperative pain in surgical patients.

Adolescent↗

PubMed1995

II. Do chronic pain patients' perceptions about their preinjury jobs differ as a function of worker compensation and non-worker compensation status?

OBJECTIVES: (1) To demonstrate a relationship between intent to return to preinjury job and preinjury job perceptions about that job; and (2) to demonstrate that worker compensation chronic pain patients (WC CPPs) would be more likely than non-worker compensation chronic pain patients (NWC CPPs) not to intend to return to a preinjury type of job because of preinjury job perceptions. STUDY DESIGN: The relationship between preinjury job perceptions and intent to return to the preinjury job was investigated and compared between worker compensation (WC) and nonworker compensation (NWC) chronic pain patients (CPPs). Within the WC and NWC groups CPPs not intending to return to their preinjury type of work were compared to those CPPs intending to return on preinjury job perception. BACKGROUND DATA: Compensation status, being a WC CPPs or being a non-WC CPPs, has been claimed to be predictive or not predictive of return to work post pain treatment. These studies have, however, ignored the preinjury job stress perception variable as an area of research. METHODS: WC CPPs were age- and sex-matched to NWC CPPs and statistically compared on their responses to rating scale and yes/no questionnaires for intent to return to work and perceived preinjury job stress. In a second analysis, both the WC and NWC groups were divided according to their intent to return to work and statistically compared on their responses to these questionnaires. RESULTS: Both male and female WC CPPs were less likely than their counterparts to intend to return to their preinjury job. Both WC and NWC were found to complain of preinjury job complaints, and these complaints were found to differ between WC and NWC CPPs. An association between intent not to return to work and the perceptions of preinjury job dissatisfaction and job dislike was found for male and female WC CPPs and for male and female NWC CPPs. CONCLUSIONS: There may be a relationship between some preinjury job perceptions and intent to return to the preinjury type of work in some groups of CPPs. However, a specific relationship between WC status, intent not to return to the preinjury type of work, and preinjury job perceptions in comparison to NWC CPPs could not be demonstrated.

Accidents, Occupational↗

PubMed1979

Evaluation of sedative/analgesic combination for postoperative pain.

Current pain concepts suggest a dual role in pain perception. Both motivational, effective, and somatosensory components are noted. Pain affects the patient's psyche and, conversely, the patient's state of mind modifies pain perception. Consequently, it might be expected that a sedative/analgesic combination might be more effective than either the sedative or the analgesic alone in controlling pain. A clinical study was carried out to compare a promethazine-A.P.C. combination with promethazine and A.P.C. alone. One hundred forty-nine patients undergoing third molar removal were studied, with each patient serving as his own control. The results indicated a significant difference between the promethazine-A.P.C. combination and prometazine alone or Phenergan alone. No significant difference was noted between the promethazine-A.P.C. combination and A.P.C. alone.

Anxiety↗

PubMed1984

Relevant and irrelevant anxiety in the reaction to pain.

Despite its importance in pain perception, there is a paucity of research investigating the influence of anxiety. This study tested the proposition that anxiety can lead to the exacerbation of pain perception when the source of anxiety is related to the pain experience. When the source is related to something else, anxiety may even reduce the reaction to pain. Sources of anxiety were manipulated in the laboratory--anxiety related to pain and anxiety related to successful learning or the combination of anxiety related to both pain and learning. Verbal, physiological, and behavioral differences were obtained showing that focus upon both the pain and the learning task yielded the strongest pain reactions, while focus upon the learning alone yielded the lowest pain reaction, but the largest learning errors. Focus upon pain was in-between. The theoretical implications of these data were discussed.

Adult↗

PubMed1989

Anxiety and pain response changes across treatment: sensory decision analysis.

Relationships between anxiety and pain perception were investigated by comparing pre- and post-pain reactions of highly anxious detoxified substance abusers categorized on the basis of anxiety level changes over treatment. Sensory decision theory methodology was applied to measure discriminative and decisional aspects of pain response. Men exhibiting significant pre-post-anxiety state decreases showed greater discriminability index increases and greater response bias index decreases at post-test, compared to their counterparts exhibiting minimal changes in severe anxiety levels across treatment. Findings have relevance for understanding pain perception and interventions in clinical samples.

Adult↗

PubMedDate not supplied

Understanding chronic pain and the mind-body connection.

This article investigates the mind-body connection in chronic pain. A discussion of pain physiology is designed to identify the role of the neurological system in chronic pain perception. The gate control theory and the neurotransmitter theory of pain are explored. A description of mind-body and pain management methods, and an illustrative case study are provided. The information presented concerning mind-body connection in chronic pain perception will enable practicing nurses to be more fully aware of the chronic pain phenomenon, and lead to better chronic pain assessment, management, and evaluation.

Adaptation, Psychological↗

PubMed1998

Functional mapping of pain-related activation with echo-planar MRI: significance of the SII-insular region.

Activation in numerous regions of the brain is likely to be involved in the complex neural network function of pain perception. To detect the cortical representation during nonpainful and painful stimuli, which were presented using electrical finger stimulation in six normal right-handed male volunteers, we performed echo-planar functional magnetic resonance imaging (fMRI). Using a 1.5-T MR system that scanned the supratentorial region of the brain, we obtained multislice BOLD-based functional MR images with single-shot gradient-echo echo-planar imaging (EPI). The data show that dispersed brain regions are activated during painful stimulation, and especially demonstrate the significance of the SII-insular region in pain perception.

Adult↗

PubMed1996

Pain mechanisms in osteoarthritis of the knee: effect of intraarticular anesthetic.

OBJECTIVE: The causes of pain in osteoarthritis (OA) remain unclear. We examined the effect of intraarticular (IA) local anesthetic (LA) on pain perception in OA knee to test the hypothesis that pain arises from structures in contact with the intraarticular surface. The effect of intervention on one knee on perception of pain in the other was also studied. METHODS: Using a single blind, blind observer design, 20 subjects with bilateral symptomatic OA knee were randomized to receive either IA LA (bupivacaine 0.25%, 5 ml) or placebo into the most painful knee. Pain from both knees was assessed at 1 h, 24 h, and 7 days using a 100 mm visual analog scale (VAS). Pain descriptors using a standardized questionnaire (McGill) were recorded. RESULTS: At 1 h there was a significant fall in pain in LA knees (median VAS 61.5 to 0.0; p = 0.007). The change at VAS was significantly different between knees receiving LA and placebo (median change -45.5 vs +3.5; p = 0.03). 6/10 LA knees scored 0 on VAS at 1 h. Noninjected knees also showed a fall in pain scores. For knees contralateral to those receiving LA, the fall was from median 28.0 to 1.0 (p = 0.08). The reduction in pain was much less in knees contralateral to those receiving placebo (median 43.5 to 38.0), though the difference between the changes did not reach statistical significance. VAS scores remained below baseline for 7 days, though this difference was not significant. McGill pain scores fell in the LA group (for all categories of pain), but did not change in the placebo group. CONCLUSION: Pain in some cases of OA knee can be abolished by IA LA, suggesting that the structures responsible for pain are in contact with the intraarticular environment. As well, interventions in one knee have significant effects on pain perception in the contralateral knee.

Aged↗

PubMed1998

Memories of chronic pain and perceptions of relief.

Clinicians and researchers often ask patients to remember their past pain. They also use patient's reports of relief from pain as evidence of treatment efficacy, assuming that relief represents the difference between pretreatment pain and present pain. We have estimated the accuracy of remembering pain and described the relationship between remembered pain, changes in pain levels and reports of relief during treatment. During a 10-week randomized controlled clinical trial on the effectiveness of oral appliances for the management of chronic myalgia of the jaw muscles, subjects recalled their pretreatment pain and rated their present pain and perceived relief. Multiple regression analysis and repeated measures analyses of variance (ANOVA) were used for data analysis. Memory of the pretreatment pain was inaccurate and the errors in recall got significantly worse with the passage of time (P < 0.001). Accuracy of recall for pretreatment pain depended on the level of pain before treatment (P < 0.001): subjects with low pretreatment pain exaggerated its intensity afterwards, while it was underestimated by those with the highest pretreatment pain. Memory of pretreatment pain was also dependent on the level of pain at the moment of recall (P < 0.001). Ratings of relief increased over time (P < 0.001), and were dependent on both present and remembered pain (Ps < 0.001). However, true changes in pain were not significantly related to relief scores (P = 0.41). Finally, almost all patients reported relief, even those whose pain had increased. These results suggest that reports of perceived relief do not necessarily reflect true changes in pain.

Adolescent↗

PubMed2005

Anterior cingulate cortical neuronal activity during perception of noxious thermal stimuli in monkeys.

It has been reported that the anterior cingulate cortex (ACC) has a variety of functions relating to pain as well as pain perception. However, the underlying mechanisms for those functions remain unclear. To elucidate the functional role of the ACC in pain perception and pain-related functions such as attention to pain and escape from pain, single neuronal activity was recorded from the ACC, and the behavioral correlates of this neuronal activity was studied. A total of 667 neurons were recorded from the ACC in awake behaving monkeys. Twenty-one had modulated activity during a heat-detection task. Eighteen of these increased their firing frequency following an increase in stimulus temperature, whereas three of them had decreased firing during heating of the face. Seventy-five percent of heat-evoked responses of heat-responsive ACC neurons were significantly depressed when monkeys detected the change in magnitude of illumination of a light presented on the front panel. The neuronal activity was significantly higher when monkeys escaped from a noxious heat stimulus than when the monkeys detected a small change in temperature (T2) above a larger initial shift (T1). No relationship between firing frequency and detection latency of the T2 stimulation was observed. These findings suggest that ACC nociceptive neurons are involved in attention to pain and escape from pain but not in the sensory discriminative aspect of pain.

Action Potentials↗