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Results for “Pain Perception”

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At least 145 records · Page 8Linked to original sources

PubMed1998

The effects of branched chain amino acid infusion on pain perception and plasma concentrations of monoamines.

Infusions of branched chain amino acids (BCAA) have been shown to have several CNS-mediated effects including antinociceptive action. We investigated the effects of BCAA infusion on pain perception, respiratory control, and plasma monoamine concentrations. Six healthy female volunteers were given in a double-blind, random, crossover design an 8-h infusion (1.75 ml/kg/h) of either (a) Ringers lactate, (b) conventional 4% amino acid solution, or (c) 4% BCAA solution with intervals of at least 48 h. Respiratory control was evaluated with continuous capnography. Pain perception was measured using dental dolorimetry for sharp pain, and pain transmitted by afferent C-fibers was evaluated with tourniquet test. Changes in vigilance were measured using critical flicker fusion technique. Evaluations were made for baseline, and after 2.5, 5, and 8 h. Plasma samples were collected at the same time points for amino acid and monoamine analysis. BCAA infusion resulted in significant increases of plasma concentrations of all BCAAs, with a simultaneous decrease in concentrations of aromatic amino acids. Of the measured monoamines and their metabolites dihydroxyphenylacetic acid (DOPAC) decreased, showing significant treatment effect for BCAA. Despite these changes no significant effect of BCAAs on respiratory control, vigilance, or pain perception was observed. In conclusion, despite significant changes in plasma concentrations of both amino acids and DOPAC, BCAA infusion did not show any clinically relevant antinociceptive effect.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1994

Altered pain perception and psychosocial features among women with gastrointestinal disorders and history of abuse: a preliminary model.

OBJECTIVES: To evaluate the relationships between sexual/physical abuse, pain perception, environmental events, coping strategies, and psychiatric morbidity in a sample of female patients with painful gastrointestinal disorders. PATIENTS: Fifty paid volunteers from a tertiary care center including 13 patients with gastroesophageal reflux disease (GERD), 26 with noncardiac chest pain (NCCP), and 11 with irritable bowel syndrome (IBS). MEASUREMENTS: (1) Sexual and physical abuse interview questions; (2) Structured psychiatric interview; (3) Self-report questionnaires: demographics, clinical pain measurement, Millon Behavioral Health Inventory, Hassles and Uplifts Scales, Sickness Impact Profile, Life Experiences Survey, Pain Beliefs and Perceptions Inventory, and Coping Strategies Questionnaire; (4) Pain Perception and Sensory Decision Theory tasks. RESULTS: Fifty-six percent of the sample reported a history of sexual/physical abuse. Abuse was significantly more prevalent among patients with GERD (92%) and IBS (82%) compared with those with NCCP (27%). Abused patients, relative to nonabused patients, had significantly lower pain threshold levels in response to finger pressure stimuli and significantly lower cognitive standards for judging stimuli as noxious. Abused patients reported significantly higher levels of functional disability and a significantly greater number of psychiatric disorders, minor daily hassles, and pain syndromes unrelated to gastrointestinal disorders. In addition, abused patients more frequently blamed themselves for their pain and reported significantly greater use of maladaptive pain coping strategies than nonabused patients. CONCLUSION: These data suggest that the relationships between abuse, disability, multiple pain syndromes, and health care seeking behavior are mediated by abnormal pain perception, psychiatric disorders, disruption of physical function, and environmental stressors.

Adaptation, Psychological↗

PubMed2001

Age-related differences in pain perception and report.

The clinical and laboratory-based evidence for age-related differences in pain perception and report are reviewed. Most clinical studies suggest a relative decrease in the frequency and intensity of pain symptoms associated with myocardial complaints, visceral infections, musculoskeletal conditions, and postoperative and malignant pain problems in adults of advanced age. The findings from experimentally controlled laboratory investigations are more equivocal and vary according to the type and intensity of noxious stimulation. Nonetheless, such studies also provide some additional support for the notion of an age-related decrease in pain perception and report. Evidence has not determined whether the observed changes are caused by the aging process or reflect other age-associated effects, including an increased presence of comorbid disease, biocultural cohort effects, or altered psychosocial influences.

Adolescent↗

PubMed2005

Evaluating effects of preservative-containing saline solution on pain perception during botulinum toxin type-a injections at different locations: a prospective, single-blinded, randomized controlled trial.

Pain is a side effect of botulinum toxin type-A (BTX-A) injections. The efficiency of the preservative-containing saline solution used as the "dilution solution" for controlling the pain felt during multiple injections in different areas has been investigated by a prospective, randomized, single-blinded, controlled study. A total of 93 patients were divided into three groups for the study. All the patients were given BTX-A. Of these 93 patients, 60 received injections in the upper face, 15 in the neck, and 18 in the axillary regions. The visual analog scale (VAS), a single-dimension pain intensity rating scale, was used to evaluate pain perception. The average VAS values for pain sensation experienced by the groups were 1.2 of 10 points for the upper face area in the experimental group (n = 60) and 4.5 point for the control group. In the neck region (n = 15), the respective scores were 0.6 in the experimental group and 3.9 in the control group. Finally, in the axillary region (n = 18), the respective values were 0.9 and 5.1. The authors conclude that the preservative-containing saline solution significantly decreased pain perception during BTX-A injections (p = 0.000).

Adult↗

PubMed1997

Sickle cell-related pain: perceptions of medical practitioners.

Pain is the most common problem encountered by patients with sickle cell disease (SCD). We report the results of a survey sent to hematologists and emergency department (ED) physicians regarding their perceptions and practices concerning pain and its management. Hematologists and ED physicians differed considerably in their perceptions about the natural history of the pain, and about the percentage of patients who are addicted to analgesics. Fifty-three percent of the ED physicians and 23% of the hematologists thought that more than 20% of patients are addicted. These beliefs and perceptions about SCD-related pain and the prevalence of addiction must be addressed if clinical care is to be changed substantively.

Anemia, Sickle Cell↗

PubMed2005

Sex differences in nociceptive withdrawal reflex and pain perception.

Experimentally induced pain often reveals sex differences, with higher pain sensitivity in females. The degree of differences has been shown to depend on the stimulation and assessment methods. Since sex differences in pain develop anywhere along the physiological and psychological components of the nociceptive system, we intended to compare the nociceptive flexion reflex (NFR) as a more physiological (spinal) aspect of pain procession to the verbal pain report of intensity and unpleasantness as the more psychological (cortical) aspect. Twenty female and twenty male healthy university students were investigated by use of nociceptive flexion reflex threshold (staircase method) after electrical stimulation of the N. suralis. Furthermore, we assessed supra-threshold reflex responses (latency, amplitude and area) by applying 10 stimuli 5 mA above reflex threshold. Following each stimulation, the subjects provided pain ratings of intensity and unpleasantness on a visual analogue scale. Females exhibited marked lower nociceptive flexion reflex thresholds than males, while the supra-threshold reflex response tailored to the individual reflex threshold did not show any significant differences. The verbal pain ratings, corrected for NFR threshold, were not found to differ significantly. The large sex differences in nociception that were present in NFR threshold but not in the pain ratings corroborate the hypothesis that spinal processes contribute substantially to sex differences in pain procession.

Adult↗

PubMedDate not supplied

Children's medical fears, coping behaviors, and pain perceptions during a lumbar puncture.

This study explored the relationships among medical fears, coping behaviors, and acute pain perceptions in 17 children with cancer who were encountering a painful medical procedure. The children completed the Child Medical Fear Scale (CMFS) before undergoing a lumbar puncture (LP), which was videotaped. The children's coping behaviors during the procedure were rated independently and classified as active or passive behaviors. Immediately following the LP, the children, using a pictorial scale, reported their pain perceptions. Most of the children's scores on the CMFS indicated a moderately low level of fear of medical experiences. A majority of the children perceived a great deal of pain during the LP. During the five phases of the painful medical procedure, more than half of the children exhibited a combination of active and passive behaviors. No significant differences were found between exhibited active or passive coping behaviors and reported medical fear levels; however, children who exhibited passive coping behaviors reported more pain than those who demonstrated active coping behaviors. Implications for practice relate to the need for continual preparation and support of children during a painful procedure.

Adaptation, Psychological↗

PubMed1997

Functional localization of pain perception in the human brain studied by PET.

To elucidate the functional localization and somatotopic organization of pain perception in the human cerebral cortex, we studied the regional cerebral blood flow using positron emission tomography during selective painful stimulation in six normal subjects. Response to a painful stimulus was elicited using a special CO2 laser, which selectively activates nociceptive receptors, to the hand and foot. Multiple brain areas, including bilateral secondary somatosensory cortices (SII) and insula, and the frontal lobe and thalamus contralateral to the stimulus side, were found to be involved in the response to painful stimulation. While our data indicate that the bilateral SII play an important role in pain perception, they also indicate that there is no pain-related somatotopic organization in the human SII or insula.

Adult↗

PubMed1998

Attentional control of pain perception: the role of hypochondriasis.

The role of hypochondriasis in the attentional control of pain perception was investigated in 28 in-patients (12 women and 16 men) at a hospital for psychosomatic disorders, who had been classified into high- and low-hypochondriacal categories by means of the Illness Attitude Scales (IAS). The two groups did not differ in their basic pain sensitivity based on their heat pain thresholds. Attentional control was manipulated by a mental arithmetic task, resulting in one experimental condition with distraction and one without distraction. In both of the conditions, subjects rated the intensity and the unpleasantness of nonpainful and painful heat stimuli on visual analog scales (VAS). Distraction significantly reduced the perceived intensity and unpleasantness of the stimuli at painful levels but not at nonpainful levels. Contrary to our expectation, the individual level of hypochondriasis did not influence this result. Although distraction seemed to have a strong influence on pain perception, hypochondriasis as a symptom or a trait did not contribute to this effect.

Adult↗

PubMed1986

Comparison of pain perception in normotensives and borderline hypertensives by means of a tooth pulp-stimulation test.

Recent studies indicate a reduced sensitivity to pain in genetically and experimentally hypertensive rats. A similar finding is also reported for human established hypertension. However, to our knowledge, no data have been reported in borderline hypertension. The aim of this study was to assess in subjects with borderline hypertension the sensory and pain thresholds by a noninvasive pulp-stimulation test performed with a commercial pulp tester that delivered stepwise increased electrical stimuli to four healthy teeth. The data reported are the means of measurements. In order to assess the possible importance of differences in the selection of the controls, two distinct groups of normotensives were chosen, one of volunteers and the other of outpatients. Significantly higher values for the pain and sensory thresholds were observed in borderline hypertensives compared with pooled normotensives. No significant effect on pain perception could be observed for sex, whereas a significant tendency toward higher threshold levels was found for younger subjects. In two normotensive groups, the sensory and pain thresholds were significantly higher in volunteers than in patients. These results suggest that changes in pain perception are present not only in established hypertension but also in borderline hypertension and, moreover, that differences in the selection of normotensive controls can have important influences on the results.

Adult↗

PubMed1991

Impairment of corneal pain perception in cluster headache.

Despite many studies, the mechanisms underlying the pathogenesis of pain in cluster headache (CH) still remain obscure. An involvement of substance P (SP) containing neurons of the Gasserian ganglion and/or of the spinal trigeminal nucleus has recently been suggested, e.g., by impairment of inhibitory descending pathways on trigeminal nociceptive neurons. The electrically elicited corneal reflex was studied in 21 CH patients (15 in active phase, 6 in remission). This method allows simultaneous measurements of the trigemino-facial reflex and corneal pain perception. A significant reduction of pain thresholds (more evident on the pain side) was observed in CH during the active phase, while normal values were recorded during the remission phase. Ten out of 15 patients in the active phase showed a significantly reduced corneal pain threshold on the pain side, while tactile sensibility was normal. Moreover, latency, amplitude and duration of the corneal reflex were normal for both painful and painless stimulations during both phases. The threshold of the nociceptive muscular response in the active phase was significantly reduced, suggesting that the excitability of trigeminal nociceptive neurons or of the motor neurons is increased in CH. The results agree with the hypothesis that a reversible impairment of several integrative functions, including the activity of trigeminal pain control system, exists in CH during the active phase.

Adult↗

PubMed2000

Effect of transcutaneous electrical nerve stimulation on pain perception threshold of human teeth: a double-blind, placebo-controlled study.

In this double-blind, placebo-controlled study, we studied the effect of three different transcutaneous electrical nerve stimulation (TENS) devices with extra- and intraoral electrodes on the pain perception thresholds of 234 unrestored, caries-free human teeth of 66 healthy individuals subjected to stimulation with an electric pulp tester. A placebo control collective of 64 healthy subjects received no electrical stimulation, since an inactive TENS device was used. In all tooth types tested (maxillary and mandibular incisors and premolars), the use of the active TENS devices resulted in an increase of 16.3-32.5% versus baseline in the pain perception threshold. The differences between active TENS and baseline were statistically significant for both TENS devices using extraoral electrodes (P < 0.05). No statistically significant differences were found between the different devices tested (P > 0.05). In the placebo collective, the increase in the pain perception threshold ranged between 6.4% and 10.3% versus baseline. There were no significant differences between placebo TENS and baseline on the one hand and between placebo TENS and the active TENS devices on the other hand (P > 0.05). The findings suggest that, as an alternative to local anesthetics, TENS seems not to be useful in the case of painful dental interventions, since it offered only minor advantages over a placebo.

Adult↗

PubMed2000

Role of histamine H(1) receptor in pain perception: a study of the receptor gene knockout mice.

To study the participation of histamine H(1) receptors in pain perception, histamine H(1) receptor knockout mice were examined for pain threshold by means of three different kinds of nociceptive tasks. These included assays for thermal nociception (hot-plate, tail-flick, paw-withdrawal), mechanical nociception (tail-pressure), and chemical nociception (abdominal constriction, formalin test, capsaicin test) which evoked pain by the activation in nociceptive Adelta and C fibers. The mutant mice lacking histamine H(1) receptors showed significantly fewer nociceptive responses to the hot-plate, tail-flick, tail-pressure, paw-withdrawal, formalin, capsaicin, and abdominal constriction tests. Sensitivity to noxious stimuli in histamine H(1) receptor knockout mice significantly decreased when compared to wild-type mice. This data indicates that histamine plays an important role in both somatic and visceral pain perceptions through histamine H(1) receptors. The difference in the effect of histamine H(1) receptors antagonist, the active (D-) and inactive (L-) isomers of chlorpheniramine on ICR mice further substantiates the evidence of the role of histamine H(1) receptors on pain threshold.

Animals↗

PubMed1996

The effect of age on A delta- and C-fibre thermal pain perception.

It has been suggested that ageing may have a differential effect on C fibre-mediated protopathic/tonic pain versus epicritic/phasic pain perception mediated by A delta fibres. The present study attempted to independently assess age-related changes in the function of A delta- and C-nociceptive fibres by examining CO2 laser-induced thermal pain thresholds before, during and after a compression block of the superficial radial nerve in 15 young and 15 healthy elderly adult subjects. Nerve block efficacy was monitored via measures of cold, warm and mechanical threshold, and simple reaction time. During nerve compression block, reaction time and mechanical threshold increased, cold sensation became impaired while warm sensation remained unaffected throughout the test in both groups. With respect to pain sensitivity, young adults exhibited significant increases in thermal pain threshold during A-fibre block while pain threshold remained relatively stable across the 3 test periods in the elderly group. It would appear that elderly adults rely predominantly on C-fibre input when reporting pain whereas younger adults utilise additional input from A delta fibres. Subsequent analysis revealed that during pre- and post-block periods, older adults exhibited a significant elevation in thermal pain threshold; however, when A delta-fibre function was impaired and only C-fibre information was available, both groups responded similarly. These findings support the notion of a differential age-related change in A-fibre-mediated epicritic pain perception versus C-fibre-mediated protopathic pain.

Adult↗

PubMed2004

Adelta nociceptor response to laser stimuli: selective effect of stimulus duration on skin temperature, brain potentials and pain perception.

OBJECTIVE: To disclose a possible effect of duration of pulsed laser heat stimuli on Adelta nociceptor responses, skin temperature profiles, brain evoked potentials and pain perception. METHODS: We used a laser stimulator which works in the millisecond range and allows us to change the duration of the pulse while keeping the total energy of the stimulus constant. In 10 healthy volunteers, we measured the intensity of perceived pain with a 0-10 scale and the latency and amplitude of the early N1 and late N2 components of the scalp potentials evoked by laser pulses of equal energy and three different stimulus durations (2, 10, and 20 ms). Using a specifically developed pyrometer with a temporal resolution lower than 1 ms we also measured stimulus-induced changes of skin temperature. RESULTS: Stimulus duration significantly influenced temperature rise times, pain perception, and brain potentials. Shorter stimulus durations yielded steeper slopes in the skin temperature profiles and higher pain ratings, shortened the latency of the N1 and N2 components, and increased the amplitude of N1. CONCLUSIONS AND SIGNIFICANCE: The shorter stimulus duration shortens receptor activation times and yields a more synchronous afferent volley, thus providing a stronger spatial-temporal summation at central synapses that enhances intensity of first pain and brain potentials. This may prove useful in clinical applications.

Adult↗

PubMed2003

Different lipid profiles as constituencies of liquid formula diets do not influence pain perception and the efficacy of opioids in a human model of acute pain and hyperalgesia.

Nutritional support and pain control by medication are often used concomitantly, but interactions are hardly investigated. A randomised, double-blind, cross-over study in ten right-handed volunteers was performed evaluating the influence of cholecystokinin (CCK)-excretion on the perception of pain in a standardised model. CCK-excretion was induced by a liquid formula diet with either long- or medium-chain triglycerides (LCT, MCT). Plasma samples were drawn over a 60 min period in 15-min intervals and CCK and somatostatin (SMS) were measured by radioimmunoassay (RIA). Gastric emptying was evaluated by C-13-breath testing. Transcutaneous electrical stimulation at a high current density (5 Hz, 70.1+/-5.8 mA) was used to provoke acute pain and stable areas of secondary mechanical hyperalgesia and pinprick allodynia for 2 h. Ongoing pain ratings as well as extension of pinprick-hyperalgesia and allodynia were compared between both liquid formula diets. In a second series of experiments, alfentanil (4.1+/-0.5 mg) was administered for 90 min using target-controlled infusions and measurements were performed as stated above. Oral administration of LCT as well as MCT may lead to different CCK blood levels, but we found no evidence for CCK-induced effects on pain sensation, touch-evoked allodynia, secondary hyperalgesia or morphine-induced anti-nociception in humans. In our studies, liquid formula diets did not influence acute pain perception or the efficacy of opioids in a human model of pain.

Acute Disease↗

PubMed2002

Changes in pain perception during treatment with angiotensin converting enzyme-inhibitors and angiotensin II type 1 receptor blockade.

OBJECTIVES: Besides the well-known role of the angiotensin system in blood pressure control, an interaction of angiotensin and pain perception has been suggested. This study sought to investigate whether an angiotensin converting enzyme inhibitor, which facilitates bradykinins, algesic peptides, and/or an AT1 receptor antagonist may modify hypertension-related hypoalgesia in humans. The study was approved by the ethical committee of our Department. METHODS: A total of 22 hypertensive patients were submitted to dental pulp stimulation to obtain the dental pain threshold and tolerance, and to 24 h blood pressure monitoring together with a control group of 55 normotensives. Then the hypertensives were randomized to enalapril or losartan treatment and were re-evaluated (dental pain perception and ambulatory monitoring) after 8 weeks of the first treatment and after an additional 8 weeks of the second treatment. RESULTS: Untreated hypertensives showed a reduced perception to painful stimuli when compared with normotensives. A significant reduction of both pain threshold and tolerance was observed during the anti-hypertensive treatments (Friedman test: P = 0.007 and P = 0.006, respectively). Pain sensitivity was similar during the two treatments and it did not differ from pain sensitivity values of normotensive controls. ANCOVAs were computed to evaluate the relationship between anti-hypertensive agents and pain sensitivity, after controlling for blood pressure. A 24 h mean pressure served as covariate, removing any effect of blood pressure; a significant difference was observed entering both pain threshold and tolerance as dependent variables (F = 5.28, P = 0.0076; F = 8.16, P = 0.0007, respectively). CONCLUSIONS: Both the angiotensin converting enzyme inhibitor enalapril and the AT1 receptor blocking agent losartan acted similarly on pain threshold and tolerance, pain sensitivity being increased during the two anti-hypertensive treatments. The blood pressure reduction during drug assumption could not account for the pain sensitivity changes observed. The latter may be due to a specific pharmacodynamic mechanism mediated through angiotensin II AT1 receptors.

Adult↗

PubMed2001

An examination of pain perception and cerebral event-related potentials following carbon dioxide laser stimulation in patients with Alzheimer's disease and age-matched control volunteers.

BACKGROUND: Pain perception is known to depend on integrated cognitive processing. Alzheimer's disease affects 5% to 10% of older adults, but the impact of this disease on pain sensitivity and report has yet to be fully investigated. AIM OF INVESTIGATION: The present study examined pain threshold, the reliability of pain report and the central nervous system processing of noxious input, as indexed by cerebral event-related potentials (CERP). METHODS: Carbon dioxide laser detection and heat pain thresholds were determined on the hand dorsum of 15 healthy older adults (Mini-Mental State Examination [MMSE] score 29.9 +/- 0.3) and 15 persons with cognitive impairment (MMSE score 12.7 +/- 6.1). Using an array of 15 silver/silver chloride scalp electrodes, the CERP and subjective rating of stimulus intensity were recorded after fixed intensity, 25 W laser stimuli. RESULTS: Compared with age-matched controls, the detection threshold for just noticeable sensation was significantly increased in elderly adults suffering from Alzheimer's disease. There was no difference in pain threshold intensity between persons with cognitive impairment and controls, although the former group was less reliable in reporting detection and pain threshold sensations. The subjective rating of a 25 W stimulus was virtually identical in both groups, and the amplitude of the major CERP component (P400) was similar; however, cognitively impaired adults exhibited a significant increase in the latency of the P400 response. CONCLUSIONS: The present findings indicate that pain perception in response to an acute heat pain stimulus is not diminished in older persons with cognitive impairment. Patients with Alzheimer's disease may be slightly less reliable in threshold pain report, although the subjective rating of evoked pain and the level of poststimulus cortical activation following noxious stimulation were found to be similar to those of controls. A longer latency of the CERP may suggest slower cortical processing of nociceptive input by persons with Alzheimer's disease.

Aged↗