scholarly journals Neural markers of nociceptive input and pain intensity coding: a signal detection approach

2019 ◽  
Author(s):  
Brianna Beck ◽  
Stephanie Cook ◽  
Giandomenico Iannetti ◽  
Patrick Haggard
Keyword(s):  
Electrical Stimulation ◽  
Signal Detection ◽  
Pain Intensity ◽  
Stimulus Intensity ◽  
Pain Perception ◽  
Electrical Stimulus ◽  
Afferent Input ◽  
Individual Variability ◽  
Healthy Human ◽  
Subjective Pain

The N2 and P2 vertex waves are the largest electroencephalographic (EEG) responses evoked by transient nociceptive stimuli. N2 and P2 amplitudes often correlate with both stimulus energy and pain intensity. However, studies using paradigms that dissociated afferent input from stimulus salience suggested the N2 and P2 waves primarily reflect supramodal salience, rather than being selective for nociception or pain. Here we investigated how well EEG responses to nociceptive laser stimuli discriminate stimulus intensities and subjective pain in healthy human volunteers. Specifically, we applied signal detection theory (SDT) to calculate how well single-trial amplitudes of stimulus-related EEG responses (contralateral N1 wave, vertex N2 and P2 waves, and gamma-band oscillations) discriminate between two laser energies (neuro-d’obj), and between participants’ reports of “high” or “low” pain intensity (neuro-d’subj). As a control, we applied the same procedure to similar brain potentials evoked by non-painful electrical stimulation. Participants’ perceptual sensitivity to stimulus intensity (d’) was similar between modalities, indicating that laser and electrical stimulus discriminations were similarly difficult. Laser-evoked N1, N2 and P2 waves were sensitive to stimulus intensity, whereas the same waves evoked by electrical stimulation showed minimal sensitivity. Inter-individual differences in laser-evoked N1, N2 and P2 neuro-d’obj also predicted inter-individual variability in nociceptive sensitivity (d’). Together, these findings show that the laser-evoked potential—elicited by stimuli at long, variable intervals—reflects nociceptive intensity discrimination. Further, the laser-evoked N2 wave captured trial-by-trial variability in pain perception that was unrelated to stimulus intensity. This indicates that the N2 carries particular information about subjective pain intensity.

scholarly journals Onset hyperalgesia and offset analgesia: Transient increases or decreases of noxious thermal stimulus intensity robustly modulate subsequent perceived pain intensity

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0231124
Author(s):  
Benedict J. Alter ◽  
Mya Sandi Aung ◽  
Irina A. Strigo ◽  
Howard L. Fields
Keyword(s):  
Pain Intensity ◽  
Stimulus Intensity ◽  
Noxious Stimulus ◽  
Thermal Stimulus ◽  
Experienced Pain ◽  
Perceived Pain ◽  
Subjective Pain ◽  
Higher Temperature ◽  
Absolute Magnitudes ◽  
Lower Temperature

Reported pain intensity depends not only on stimulus intensity but also on previously experienced pain. A painfully hot temperature applied to the skin evokes a lower subjective pain intensity if immediately preceded by a higher temperature, a phenomenon called offset analgesia. Previous work indicated that prior pain experience can also increase subsequent perceived pain intensity. Therefore, we examined whether a given noxious stimulus is experienced as more intense when it is preceded by an increase from a lower temperature. Using healthy volunteer subjects, we observed a disproportionate increase in pain intensity at a given stimulus intensity when this intensity is preceded by a rise from a lower intensity. This disproportionate increase is similar in magnitude to that of offset analgesia. We call this effect onset hyperalgesia. Control stimuli, in which a noxious temperature is held constant, demonstrate that onset hyperalgesia is distinct from receptor or central sensitization. The absolute magnitudes of offset analgesia and onset hyperalgesia correlate with each other but not with the noxious stimulus temperature. Finally, the magnitude of both offset analgesia and onset hyperalgesia depends on preceding temperature changes. Overall, this study demonstrates that the perceptual effect of a noxious thermal stimulus is influenced in a bidirectional manner depending upon both the intensity and direction of change of the immediately preceding thermal stimulus.

scholarly journals Evaluation of pain intensity of the masticatory muscles after occlusal appliance and combined therapy

2020 ◽  
Vol 19 ◽  
pp. e200119
Author(s):  
Tainá Queiroz dos Santos ◽  
Giancarlo De la Torre Canales ◽  
Celia Marisa Rizzatti-Barbosa ◽  
Victor Ricardo Manuel Muñoz-Lora
Keyword(s):  
Pain Intensity ◽  
Pain Perception ◽  
Combined Therapy ◽  
Pressure Pain Threshold ◽  
Masticatory Muscles ◽  
Significance Level ◽  
Evaluation Time ◽  
Subjective Pain ◽  
Treatment Data ◽  
Reduction Of Pain

Masticatory muscle pain (MMP) is a common type of orofacial pain. Occlusal appliance (OA) is contemplated as a first-line conservative approach for chronic MMP, however, integrated biopsychosocial approaches such as counseling and self-care therapies (CSG) are also considered essential. AIM: This pilot study aimed to compare the use of a combined therapy (GSG + OA) and solely OA treatment on pain intensity related to chronic MMP over a 6-month follow-up. METHODS: For this, 20 patients diagnosed with chronic MMP using the Diagnostic criteria for temporomandibular disorders (DC/TMD) were divided into 2 groups (n=10) and treated with OA or combined therapy (CoT; OA + CSG). Electromyographic muscle activity (EMG), visual analogue scale (VAS) and pressure pain threshold (PPT) were recorded at baseline, 1, 3 and 6 months after treatment. Data was collected and statistical analysis were applied at a significance level of 5%. RESULTS: Results showed no significant differences at baseline among groups for any assessment. VAS showed that both treatments decreased subjective pain in volunteers over time, but no significant differences among both groups were observed at any evaluation time. For electromyography, CoT and OA presented no significant differences throughout the experiment neither on relaxed muscle position or maximum volunteer contraction. Finally, a significantly higher PPT for CoT was found for all muscles at the last assessment point (p<0.05). CONCLUSION: These findings suggest that both treatments are effective for the reduction of pain perception (VAS) in patients with chronic MMP. However, the addition of CSG to an OA therapy may be more beneficial for the improvement of tenderness on the same patients, at least in a long-term basis (> 3 months). Notwithstanding, a larger study should be performed to substantiate these findings.

scholarly journals Gender Differences in Subjective Pain Perception during and after Tattooing

2020 ◽  
Vol 17 (24) ◽  
pp. 9466
Author(s):  
Joanna Witkoś ◽  
Magdalena Hartman-Petrycka
Keyword(s):  
Pain Intensity ◽  
Pain Perception ◽  
Patient Characteristics ◽  
The Body ◽  
Binary Outcomes ◽  
Cycle Phase ◽  
Regression Analyses ◽  
Pain Medications ◽  
Subjective Pain ◽  
The Impact

Background: The aim of the research was to analyse the impact of gender on pain perception during and directly after tattooing, with the following predictors as covariates: the body area chosen for a tattoo, the character of the pain, the time it takes to complete the tattoo, bleeding, the level of stress, analgesics taken before the tattooing procedure, and the cycle phase. Methods: A total of 1092 participants took part in this study (F: 863, M: 229). A proprietary survey was used in the research, including patient characteristics and questions relating to the above-mentioned variables. Multiple regression analyses were used for continuous outcomes and multiple logistic regression analyses for binary outcomes. Results: Factors increasing pain during tattooing include: time B: 0.35; 95% CIs: 0.27–0.43; p = 0.001; bleeding B: 0.36; 95% CIs: 0.00–0.72; p = 0.052; level of stress B: 0.45; 95% CIs: 0.31–0.60; p = 0.001; pain medications taken before tattooing B: 1.42; 95% CIs: 0.60–2.23; p = 0.001. Factors increasing pain after tattooing include: time B: 0.21; 95% CIs: 0.15–0.27; p = 0.001; bleeding B: 0.47; 95% CIs: 0.20–0.72; p = 0.001; level of stress B: 0.15; 95% CIs: 0.04–0.26; p = 0.001. Conclusions: There was no difference between females and males in pain intensity during tattooing. Directly after the procedure, however, pain intensity was higher in women when compared to men. The most important factors increasing pain were time, bleeding, and the level of stress.

scholarly journals The onset and offset of noxious stimuli robustly modulate perceived pain intensity

2020 ◽  
Author(s):  
Benedict J. Alter ◽  
Mya Sandi Aung ◽  
Irina A. Strigo ◽  
Howard L. Fields
Keyword(s):  
Pain Intensity ◽  
Stimulus Intensity ◽  
Stimulus Change ◽  
Noxious Stimulus ◽  
Noxious Heat ◽  
Temperature Changes ◽  
Hot Temperature ◽  
Experienced Pain ◽  
Subjective Pain ◽  
Higher Temperature

AbstractReported pain intensity depends not only on stimulus intensity but also on previously experienced pain. A painfully hot temperature applied to the skin evokes a lower subjective pain intensity if immediately preceded by a higher temperature, a phenomenon called offset analgesia. This is typically evoked using a three-step noxious heat stimulus. In other clinical and laboratory settings, prior pain experience may increase pain intensity as well. Therefore, we hypothesized that even small increases in stimulus intensity within the noxious range would be accompanied by enhanced reported pain intensity. To test this possibility, we inverted the intensity order of the three-step stimulus, so that the same hot temperature is immediately preceded by an increase from a transiently lowered temperature. Using healthy volunteer subjects, we observed a disproportionate increase in pain intensity during the novel, inverted, three-step stimulus. This disproportionate increase is similar in magnitude to that of offset analgesia. Control stimuli demonstrate that these changes in pain intensity are distinct from habituation. The magnitudes of offset analgesia and the disproportionate increase in pain intensity correlate with each other but not with the absolute noxious stimulus temperature. These observations suggest that the disproportionate increase in pain intensity represents an “onset hyperalgesia.” Finally, the magnitude of both offset analgesia and onset hyperalgesia depends on preceding temperature changes. Overall, this study finds that perceptual enhancement of noxious stimulus change occurs bidirectionally and that this depends on the intensity and direction of change of the immediately preceding stimulus.

scholarly journals Unpredictable pain timings lead to greater pain when people are highly intolerant of uncertainty

2017 ◽  
Vol 17 (1) ◽  
pp. 367-372 ◽  
Author(s):  
Clémence Bélanger ◽  
Bernard Blais Morin ◽  
Andréanne Brousseau ◽  
Nicolas Gagné ◽  
Anne Tremblay ◽  
...  
Keyword(s):  
Pain Intensity ◽  
Pain Perception ◽  
Rating Scale ◽  
Numerical Rating Scale ◽  
Pain Catastrophizing ◽  
Intolerance Of Uncertainty ◽  
Time Frame ◽  
Added Value ◽  
Subjective Pain ◽  
The Impact

AbstractBackground and purposeMany psychological factors are known to influence pain perception. Among them, intolerance of uncertainty (IU) may play a key modulating role in situations where uncertainty prevails, especially uncertainty regarding the timing of painful events. The objective of this study was to explore the impact of individual differences in IUon pain perception during predictable and unpredictable stimulation timings. We hypothesized that people with high IU, as opposed to those with low IU, would perceive more pain when the timing of painful stimulations cannot be predicted, as compared to when they can.MethodsTwenty (20) healthy adults, aged between 18 and 35 years old, were recruited. Painful sensations were provoked using transcutaneous electrical stimulations of the right sural nerve. By measuring IU (Intolerance of Uncertainty Scale) and subjective pain (verbal numerical rating scale), it was possible to test the relationship between IU and pain perception, by simulating predictable and unpredictable painful experiences. This was done through cued shock interval (CSI) blocks, with either variable timing or fixed timings (long or short time frame). Self-administered questionnaires were also used to measure pain hypervigilance, pain catastrophizing, state anxiety, and trait anxiety.ResultsPearson correlations confirmed the presence of an association (r = 0.63) between IU and the change in pain intensity provoked by unpredictable stimulation timings. Importantly, this association was significant only for stimulations provided at long CSIs, indicating that higher IU scores predicted higher pain intensity scores when stimulation timings became unpredictable, and when the cued delay was long. No association was found between pain scores and other psychological variables.ConclusionsOur results show that IU moderately correlates to the change in pain intensity provoked by unpredictable stimulation timings. High IU scores were associated with a worsening of the subjective pain experience, especially during long delays in an unpredictable situation. These observations suggest that IU could be considered as a psychological variable that is able to influence pain perception in certain situations.ImplicationsAssessing and addressing IU could be an added value in pain-related therapy, especially in chronic pain.

scholarly journals Processing of Pain by the Developing Brain: Evidence of Differences Between Adolescent and Adult Females

2021 ◽  
Author(s):  
Han Tong ◽  
Thomas C. Maloney ◽  
Michael F. Payne ◽  
Christopher D. King ◽  
Tracy V. Ting ◽  
...  
Keyword(s):  
Pain Intensity ◽  
Cognitive Processing ◽  
Stimulus Intensity ◽  
Pain Perception ◽  
Anterior Cingulate ◽  
Female Adolescents ◽  
Sensitive Period ◽  
Significant Group ◽  
Brain Responses ◽  
Pain Ratings

Adolescence is a sensitive period for both brain development and the emergence of chronic pain particularly in females. However, the brain mechanisms supporting pain perception during adolescence remain unclear. This study compares perceptual and brain responses to pain in female adolescents and adults to characterize pain processing in the developing pain. Thirty adolescent (ages 13-17) and thirty adult (ages 35-55) females underwent a functional MRI scan involving acute experimental pain. Participants received 12 ten-second noxious pressure stimuli, which were applied to the left thumbnail at 2.5 and 4 kg/cm2, and rated pain intensity and unpleasantness on a visual analogue scale. We found a significant group-by-stimulus intensity interaction on pain ratings. Compared to adults, adolescents reported greater pain intensity and unpleasantness in response to 2.5 kg/cm2, but not 4 kg/cm2. Adolescents showed greater medial-lateral prefrontal cortex (PFC) and supramarginal gyrus activation in response to 2.5 kg/cm2, and greater medial PFC and rostral anterior cingulate responses to 4 kg/cm2. Adolescents showed augmented pain-evoked responses in the Neurologic Pain Signature and greater activation in the default mode (DMN) and ventral attention (VAN) networks. Also, the amygdala and associated regions played a stronger role in predicting pain intensity in adolescents, and activity in DMN and VAN regions more strongly mediated the relationship between stimulus intensity and pain ratings. This study provides the first evidence of augmented pain-evoked brain responses in healthy female adolescents involving regions important for nociceptive, affective and cognitive processing, in line with their augmented sensitivity to low-intensity noxious stimuli.

scholarly journals Differential Coding of Pain Intensity in the Human Primary and Secondary Somatosensory Cortex

2001 ◽  
Vol 86 (3) ◽  
pp. 1499-1503 ◽  
Author(s):  
Lars Timmermann ◽  
Markus Ploner ◽  
Katrin Haucke ◽  
Frank Schmitz ◽  
Rüdiger Baltissen ◽  
...  
Keyword(s):  
Pain Intensity ◽  
Stimulus Intensity ◽  
Pain Perception ◽  
Activation Pattern ◽  
Secondary Somatosensory Cortex ◽  
Healthy Humans ◽  
Somatosensory Cortices ◽  
Nociceptive Stimulus ◽  
Pain Ratings ◽  
The Right

The primary (SI) and secondary (SII) somatosensory cortices have been shown to participate in human pain processing. However, in humans it is unclear how SI and SII contribute to the encoding of nociceptive stimulus intensity. Using magnetoencephalography (MEG) we recorded responses in SI and SII in eight healthy humans to four different intensities of selectively nociceptive laser stimuli delivered to the dorsum of the right hand. Subjects' pain ratings correlated highly with the applied stimulus intensity. Activation of contralateral SI and bilateral SII showed a significant positive correlation with stimulus intensity. However, the type of dependence on stimulus intensity was different for SI and SII. The relation between SI activity and stimulus intensity resembled an exponential function and matched closely the subjects' pain ratings. In contrast, SII activity showed an S-shaped function with a sharp increase in amplitude only at a stimulus intensity well above pain threshold. The activation pattern of SI suggests participation of SI in the discriminative perception of pain intensity. In contrast, the all-or-none–like activation pattern of SII points against a significant contribution of SII to the sensory-discriminative aspects of pain perception. Instead, SII may subserve recognition of the noxious nature and attention toward painful stimuli.

Circle therapy for headache management: case studies

2020 ◽  
Vol 24 (1) ◽  
pp. 101-104
Author(s):  
Muhammad Rafiq
Keyword(s):  
Pain Intensity ◽  
Case Studies ◽  
Rating Scale ◽  
Psychological Pain ◽  
Current Case ◽  
Paired Samples ◽  
Subjective Pain ◽  
Headache Management ◽  
Test Use ◽  
Pain Rating Scale

Recent findings have indicated that hypnotic interventions produce significant decrease in pain intensity. This current case studies are focused to highlight significant impact on pain management including headache. All the patients underwent a complete observation and clinical interview and only patients with psychological pain were included in the study group. For the management of headache, a novel hypnotic intervention - Circle Therapy (CT), was applied on a group of ten patients indicating their pain intensity in the range of 8-10 on subjective pain rating scale. According to rating scale, headache above 8 was considered as severe, 5-8 moderate and < 5 as mild.  CT is a brief hypnotic technique limited to about 10 min. Post hypnosis ratings were also measured. The pre and post hypnosis data were recorded and analyzed by paired samples t test. Use of CT showed significant results between pre and post rating e.g. 9 ± 0.25 vs. 1 ± 0.21 (p < 0.001). This brief CT intervention provided an immediate relief from headache, however, this is limited to few case studies focusing on just headache. So, we recommend large sample studies to document the effects of CT in different types of pain. Citation: Rafiq M. Circle therapy for headache management: case studies. Anaesth pain intensive care 2020;24(1):__ DOI: https://doi.org/10.35975/apic.v24i1. Received – 28 December 2019; Reviewed – 10 January 2020; Accepted - 10 January 2020;

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