Heat pain threshold and tolerance show no left–right perceptual differences at complementary sites of the human forearm (original) (raw)
Related papers
A new thermal stimulation method for human psychophysical studies: Pain intensity clamping
Journal of Neuroscience Methods, 2010
A method for testing changes in pain sensitivity of human subjects over the course of prolonged thermal stimulation is introduced. It uses a Peltier-device-based thermode to generate a thermal contact stimulus, an electronic visual analog scale to continuously record the pain intensity and a system that controls selected stimulus parameters (temperature or pulse timing) as a function of the pain intensity rating. The stimulus parameter that is modulated to clamp pain intensity near a desired setpoint serves as the response variable and is used to infer pain sensitivity. Advantages of the method are that it automatically finds the stimulus magnitude that elicits predetermined pain intensity, regardless of how sensitive or insensitive the subject is, and it allows prolonged stimulation, because it does not allow pain intensity to escalate to unacceptable levels due to progressive sensitization. The subject is blinded regarding experimental effects because average pain intensity remains constant regardless of sensitization or pharmacological interventions.
The effects of stimulus location on the gating of touch by heat- and cold-induced pain
Somatosensory & Motor Research, 2000
The influence of heat-and cold-induced pain on tactile sensitivity, a ª touch gateº , was measured under conditions in which the location of the noxious stimuli was varied with respect to the tactile stimulus applied to the thenar em inence of humans. Vibrotactile thresholds were m easured in the absence of pain and during administration of a painful stimulus, with the stim ulus frequencies selected to activate independently the four psychophysical channels hypothesized to exist in human glabrous skin. Heat-induced pain produced by spatially co-localizing the noxious stimuli with the tactile stimuli was found, on average, to elevate threshold amplitude by 2.2 times (6.7 dB). Co-localized, cold-induced pain raised the average thresholds by about 1.5 times (3.6 dB). Heat-induced pain presented contralaterally produced no change in vibrotactile sensitivity indicating that the effect is probably not due to attentional mechanisms. Ipsilateral heat-induced pain caused an elevation in tactile thresholds even when the noxious and non-noxious stimuli were not co-localized, and the effect may seem to require that the painful stimulus be within the som atosensory region defined possibly in terms of dermatomal organization. Thus the effect is probably related to som atotopic organization and is not peripherally mediated. A brief discussion as to the possible locus of the touch gate within the nervous system is also given.
Neuromodulation: Technology at the Neural Interface, 2003
A BSTRACT This study was aimed to test whether the administration of transcutaneous electrical neural stimulation (TENS), heat or cold alone, or the coadministration of TENS in combination with heat or with cold may alter the thresholds of the sensory (algosity) and the affective (unpleasantness) dimensions of experimental pain. Mechanical pain induced by a pressure algometer was applied to the tibial shaft of 180 healthy volunteers before and after random application of one of the six following modalities: shamstimulation, cold, heat, TENS, combination of TENS + cold, or combination of TENS + heat. All modalities were applied in the same (L4) dermatome with the use of Thermotens (Mediseb Technologies Ltd., Hertzelia, Israel), a device which produces quantifiable combinations of thermal and electrical modalities separately or simultaneously. Only the combination of TENS + heat significantly elevated the thresholds of algosity (from 221 mmHg to 262 mmHg, p < 0.01) and of unpleasantness (from 134 ± 9 to 197 ± 9 mmHg; p < 0.001). These findings suggest that the coadministration of several physical modalities can be more efficacious in the treatment of pain than each modality alone.
European Journal of Pain, 2003
The increased use of quantitative sensory testing in the study of pain raises the need to characterize various aspects of psychophysical response to noxious stimulation in healthy subjects. The present study aims to address several issues regarding the use of heat pain stimuli: (a) Are pain scores for short-term repeated phasic stimuli consistent? (b) Does an exposure to tonic heat pain stimulus cause sensitization and change the scores for subsequent phasic stimuli? and (c) Are pain scores for phasic and tonic heat pain correlated? To address these questions, a series of four phasic heat pain stimuli of 47°C were given to the forearms of 70 healthy volunteers, over the course of an hour. Pain scores by Visual Analog Scale (VAS) were obtained for each stimulus. In 50 subjects, a tonic heat pain of 70 s duration at 47.5°C was given between the first and second phasic stimuli. Pain scores were obtained at four points along this tonic stimulus. Repeated measures ANOVA and a sensitive post hoc analysis indicated that, while the pain perception was reduced on the second, nearly immediate trial, subsequent VAS scores of pain perception were not different from the first (#1: 35:2 AE 19:2; #2: 31:4 AE 20:2, #3: 33:0 AE 21:6; and #4: 33:2 AE 20:1, respectively), with strong correlation among the phasic tests. The average tonic pain score was 53:7 AE 23:1. Administration of tonic pain stimuli did not result in different VAS scores of subsequent phasic pain stimuli, compared to those subjects who did not receive tonic pain stimuli. Tonic and phasic pain were positively correlated (e.g., r ¼ 0:45; p < 0:001 for the first phasic stimuli). However, no relation was found between the level of perceived pain, either for phasic or for tonic stimuli, and presence or absence of temporal summation during the tonic pain. In conclusion: (i) phasic pain scores assessments at 30 0 and 60 0 after baseline is consistent; (ii) tonic heat pain, despite relatively high VAS scores, does not cause a change in the scoring of subsequent phasic stimuli; and (iii) phasic and tonic pain scores correlate with each other. Thus, the normal pattern of pain perception is stable and not altered by single tonic pain stimulation.
Objective Correlate of Subjective Pain Perception by Contact Heat-Evoked Potentials
The Journal of Pain, 2008
The method of pain-evoked potentials has gained considerable acceptance over the last 3 decades regarding its objectivity, repeatability, and quantifiability. The present study explored whether the relationship between pain-evoked potentials and pain psychophysics obtained by contact heat stimuli is similar to those observed for the conventionally used laser stimulation. Evoked potentials (EPs) were recorded in response to contact heat stimuli at different body sites in 24 healthy volunteers. Stimuli at various temperatures were applied to the forearm (43°C, 46°C, 49°C, and 52°C) and leg (46°C and 49°C). The amplitudes of both components (N2 and P2) were strongly associated with the intensity of the applied stimuli and with subjective pain perception. Yet, regression analysis revealed pain perception and not stimulus intensity as the major contributing factor. A significant correlation was found between the forearm and the leg for both psychophysics and EPs amplitude.
BioMed Research International, 2013
Background. TENS (transcutaneous electrical nerve stimulation) is probably the most diffused physical therapy used for antalgic purposes. Although it continues to be used by trial and error, correct targeting of paresthesias evoked by the electrical stimulation on the painful area is diffusely considered very important for pain relief.Aim. To investigate if TENS antalgic effect is higher in the cutaneous area of the stimulated nerve when confronted to neighbouring areas.Methods. 10 volunteers (4 males, 6 females) underwent three different sessions: in two, heat pain thresholds (HPTs) were measured on the dorsal hand skin before, during and after electrical stimulation (100 Hz, 0.1 msec) of superficial radial nerve; in the third session HPTs, were measured without any stimulation.Results. Radial nerve stimulation induced an increase of HPT significantly higher in its cutaneous territory when confronted to the neighbouring ulnar nerve territory, and antalgic effect persisted beyond th...
Characterization of a novel model of tonic heat pain stimulation in healthy volunteers
Pain, 2008
The vast majority of the experimental pain studies have used acute, phasic heat stimuli to investigate the neurobiological mechanisms of pain. However, the validity of these models for understanding clinical forms of pain is questionable. We here describe the characteristics of a model of prolonged tonic heat pain stimulation and compared the responses on this test with other measures of pain. In 58 normal volunteers, we applied a 7-min lasting contact heat stimulation of 47°C to the upper leg while participants constantly rated their pain. Average pain rating during the 7-min period was 6.2 ± 0.4, females scoring higher than men (7.4 ± 0.5 vs. 5.2 ± 0.5; p < 0.005). Pain ratings showed a steady increase during the first half of the stimulation period after which they stabilized. A strong interindividual variability was observed in the time profiles of the pain ratings over the course of the 7-min stimulation period. The model showed a good test-retest reproducibility. Tonic heat pain ratings only correlated moderately with the pain threshold while stronger correlations were observed with pain tolerance and ratings of suprathreshold phasic heat pain. We conclude that the tonic heat model is a suitable model that can be applied without excessive discomfort in the majority of subjects and offers a valuable addition to the armamentarium of experimental pain models. The model can be particularly suitable for brain imaging receptor binding studies which require long stimulation periods. Ó
Europa medicophysica, 2007
Transcutaneous electrical nerve stimulation (TENS) is used worldwide for pain relief, but its mechanisms of action are not completely understood. High frequency transcutaneous peripheral nerve stimulation (HF-TPNS) is a term describing a type of TENS where a peripheral nerve is stimulated transcutaneously. The aim of the investigation was to verify the hypothesis that HF-TPNS increases the heat pain threshold in the skin territory of the stimulated nerve, during and after stimulation. Eighteen volunteers (8 men, 10 women) participated in 2 sessions conducted on different days. In each session their heat pain thresholds were measured in basal conditions and after 5, 10, 15, 25, 40, 70 min. In one session, HF-TPNS was delivered for 10 min immediately after basal evaluation (HF-TPNS session). In the other session the heat pain thresholds only were measured (control session). The superficial radial nerve was stimulated at the wrist (frequency of 100 Hz, pulse duration of 0.1 ms). The he...
Heat hyperalgesia in humans: assessed by different stimulus temperature profiles
European Journal of Pain, 2002
The aim of the present study was to investigate the effect of the rate of temperature increase on the intensity of the evoked pain before and after hyperalgesia induced by topical capsaicin. Further, hyperalgesia to suprathreshold heat stimuli was investigated. Thirteen healthy volunteers were included in the experiment. All stimuli were applied in randomised order within the volar surface of both forearms using a computer-controlled contact stimulator. In one of the forearms, the effect of the rate of temperature change was investigated for 1.0, 5.0, and 8.0°C/s reaching a peak temperature of 30.0, 33.0, 36.0, 39.0, and 42.0°C in the primary hyperalgesic area and reaching a peak temperature of 33.0, 36.0, 39.0, 42.0, 45.0, 47.0, and 49.0°C in the secondary hyperalgesic area before and after the induction of hyperalgesia. In the other forearm, the same procedure was repeated without capsaicin application as a control measurement. After the induction of hyperalgesia, the pain ratings were significantly higher in the arm treated with capsaicin compared with baseline for 36, 39, and 42°C heating rates in the primary hyperalgesic area. The pain ratings were significantly higher with 1°C/s heating rate compared with 5 and 8°C/s for 36, 39, and 42°C in the primary hyperalgesic area. Heat hyperalgesia was also observed within the secondary hyperalgesic area to pin-prick for stimulus temperatures of 45, 47, and 49°C compared with the baseline measurements. Increased ratings were found for all three heating rates in the secondary hyperalgesic area. There were no heat hyperalgesia in the control arm. In conclusion, hyperalgesia to suprathreshold heat stimuli was observed in the secondary hyperalgesic area and C-fibres play an important role in the primary hyperalgesia to heat.
Medical review, 2019
Introduction. The objective of the study was to determine the potentials and reliability of conditioned pain modulation effect in healthy population by application of a conditioning contact heat stimulus, and heat and pressure applied to the low back region as a test stimulus. Material and Methods. The study included 33 healthy subjects (average age 25.73 ? 5.35 years). Pressure and heat pain thresholds were examined on the paravertebral musculature of the lower back as test stimuli. Contact heat was used on the contralateral forearm as a conditioning stimulus. Conditioned pain modulation was calculated as the difference between pain thresholds after and before conditioning stimulus application. To assess the reliability, identical testing was performed 14 ? 2 days later. Results. The pressure and heat pain thresholds, after the conditioning stimulus, were significantly higher compared to pain thresholds obtained before the conditioning stimulus (101,63 N/cm2 ? 45,21N/cm2 vs 82,15 N...