Decrease In Pressure Pain Threshold Research Articles

Assessing central sensitization with quantitative sensory testing in inflammatory rheumatic diseases: A systematic review.

The major therapeutic challenge in inflammatory rheumatic diseases is the persistence of pain despite good responses to specific therapies. Central sensitization, which can be assessed clinically by psychophysical measurements, including quantitative sensory testing (QST), is a widely proposed mechanism for chronic pain. In this systematic review, we explored the scientific literature addressing quantitative sensory testing in inflammatory rheumatic diseases. We searched Pubmed and Embase for publications up to December 2021 concerning studies on quantitative sensory testing focusing on pain thresholds, temporal summation (TS) and conditioned pain modulation (CPM), in adult patients with chronic inflammatory rheumatism (e.g. rheumatoid arthritis, spondyloarthritis, psoriatic arthritis, juvenile idiopathic arthritis). The exclusion criteria were reviews, inclusion of children and no reported pain threshold. Data quality was assessed with the National Institutes of Health (NIH) Quality Assessment tools. We identified 27 studies (18 controlled, 9 uncontrolled) including 1875 patients with inflammatory rheumatic diseases and 795 controls. A decrease in pressure pain threshold, in favor of allodynia, was found in 12 of 14 controlled studies on patients with rheumatoid arthritis and spondyloarthritis. The results of other psychophysical tests, including TS and CPM, were inconsistent due to population heterogeneity and a lack of standardization of the patients' disease duration, activity and treatment. Our review shows that pain in chronic inflammatory rheumatism is associated with pressure allodynia. However, given the heterogeneous quality and discrepant results of studies of other QST outcome measures, the hypothesis of central sensitization involvement in pain processing in these patients cannot be confirmed.

Effectiveness of Dry Needling and Ischemic Trigger Point Compression in the Gluteus Medius in Patients with Non-Specific Low Back Pain: A Randomized Short-Term Clinical Trial.

Background: The presence of latent myofascial trigger points (MTrPs) in the gluteus medius is one of the possible causes of non-specific low back pain. Dry needling (DN) and ischemic compression (IC) techniques may be useful for the treatment of these MTrPs. Methods: For this study, 80 participants were randomly divided into two groups: the dry needling group, who received a single session of DN to the gluteus medius muscle plus hyperalgesia (n = 40), and the IC group, who received a single session of IC to the gluteus medius muscle plus hyperalgesia (n = 40). Pain intensity, the pressure pain threshold (PPT), range of motion (ROM), and quality of life were assessed at baseline, immediately after treatment, after 48 h, and one week after treatment. Results: Statistically significant differences were shown between the two groups immediately after the intervention, showing a decrease in PPT (p < 0.05) in the DN group and an increase in PPT in the IC group. These values increased more and were better maintained at 48 h and after one week of treatment in the DN group than in the IC group. Quality of life improved in both groups, with greater improvement in the DN group than in the IC group. Conclusions: IC could be more advisable than DN with respect to UDP and pain intensity in the most hyperalgesic latent MTrPs of the gluteus medius muscle in subjects with non-specific low back pain, immediately after treatment. DN may be more effective than IC in terms of PPT, pain intensity, and quality of life in treating latent plus hyperalgesic gluteus medius muscle MTrPs in subjects with non-specific low back pain after 48 h and after one week of treatment.

Comparison of dry needling and kinesio taping methods in the treatment of myofascial pain syndrome: A single blinded randomised controlled study.

The aim of this study was to compare the effectiveness of kinesio taping (KT) and dry needling (DN) in the treatment of myofascial pain syndrome (MPS) of the trapezius muscle. The patients with MPS were divided into 3 groups as those who received exercise only (control group), those who received KT and exercise (KT group) and those who received DN and exercise (DN group) by using a sealed opaque envelope randomisation method. Visual Analog Scale (VAS), Pressure Pain Threshold (PPT), Neck Disability Index (NDI) and Global Perceived Effect Scale (GPES) were measured twice at baseline and at the end of the second week by blinded evaluator. A total of 26 patients were assigned to KT group, 32 to DN group and 30 to control group. The results of the study showed that PPT, VAS and NDI scores were significantly improved in the KT (1.61±1.25, -2.66±1.24 and -7.08±6.24, respectively) and DN (1.30±1.13, -3.34±1.40 and -10.63±7.80 respectively) groups (P<.001 for all). In the control group, no significant improvement was found in the VAS (.10±1.39) and NDI (-.83±4.91) scores (P>.05), with a significant decrease in PPT (-.98±1.92) (P=.014). KT and DN methods in MPS treatment have more positive effects in terms of pain, disability and global effect compared to the control group. In the treatment of MPS, adding DN or KT to exercise programme may provide important contributions to the treatment.

Pain sensitivity increases more in younger runners during an ultra-marathon.

Ultra-endurance research interest has increased in parallel with an increased worldwide participation in these extreme activities. Pain-related data for the growing population of ultra-endurance athletes, however, is insufficient. More data is especially needed regarding the variation in the aging populations of these athletes. We have previously shown that peripheral and central pain sensitivity increases during an ultra-marathon. To further clarify these changes inpain sensitivity during ultra-endurance competition we investigated these variations in two age populations: Younger runners≤39-year-old (younger) and an older group of runners being≥40years of age (older). Subjects were recruited from ultra-marathon competitions held over a three-year period in Florida, USA. All courses were flat with either hard macadam surface or soft sandy trails; run in hot, humid weather conditions. Pressure pain threshold (PPT) was measured with a pressure algometer on the distal, dominant arm before and immediately after an ultra-marathon. Conditioned pain modulation (CPM) was also measured pre and post, immediately after the PPT by placing the non-dominant hand in a cold-water bath maintained at 13.5±1.5°C. The difference between the pre and post measurements for both PPT and CPM were calculated and referred to as ΔPPT and ΔCPM, respectively for analysis. Data were analyzed with a Mixed 2×2 (Within X Between) MANOVA. Both PPT and CPM decreased during the ultra-marathons (p<0.05) in the younger group of runners. In the older runners there was not a statistically significant decrease in PPT during the ultramarathons whereas CPM did significantly decrease statistically (p=0.031). The ΔPPT was less in the older group compared to the younger group (p=0.018). The difference between the younger and older groups ΔCPM approached statistical significance at p=0.093. This statistical evidence suggests that the overall increase in peripheral and possibly central pain sensitivity was different between our age groups. Pain sensitivity during the ultra-marathon increased more in our younger group of runners than in our older group. This study suggests that there is an unidentified factor in an older population of ultra-marathon runners that results in an attenuated increase in pain sensitivity during an ultra-endurance activity. These factors may include a decreased innate immune response, lower fitness level, lower exertion during the ultra-marathon, variation in endorphin, enkephalin, endocannabinoid and psychological factors in the older age runners.

Minocycline reduces experimental muscle hyperalgesia induced by repeated nerve growth factor injections in humans: A placebo-controlled double-blind drug-crossover study.

Hyperalgesia is a heightened pain response to a noxious stimulus and is a hallmark of many common neuropathic and chronic pain conditions. In a double-blind placebo-controlled drug-crossover trial, the effects of concomitant and delayed minocycline treatment on the initiation and resolution of muscle hyperalgesia were tested. An initial cohort (n=10) received repeated injections (5µg: days 0, 2 and 4) of nerve growth factor (NGF) in the flexor carpi ulnaris muscle of the forearm and pressure pain thresholds were collected at day 0 (control), day 7 (peak) and day 14 (recovery). A second cohort (n=18) underwent an identical procedure, however, half received a placebo between days 0 and 7 before switching to minocycline from days 7 to 14 (P1/M2), while the remaining subjects received minocycline (day 0: 200mg then 100mg b.i.d. for 7days) before switching to placebo (M1/P2). The initial cohort exhibited a diffuse muscular pain hypersensitivity with a decrease in pressure pain thresholds at day 7 before a partial return to normalcy at day 14. The P1/M2 treatment group exhibited an identical peak in hypersensitivity at day 7, however, after switching to minocycline in week 2 showed a significant reduction in muscle hyperalgesia compared with the initial cohort at day 14. The M1/P2 treatment group had significantly less (~43%) hyperalgesia at day 7 compared with the other groups. The study indicates that the administration of minocycline can reduce experimentally induced muscle pain regardless of the time of administration. In a double-blind placebo-controlled drug-crossover study, the common antibiotic minocycline was found to reduce the muscle hyperalgesia induced by intramuscular injection of nerve growth factor. The results of the study showed that both concomitant (pre-emptive) and delayed administration of minocycline can ameliorate the onset and facilitate the resolution of experimentally induced muscle hyperalgesia.

Mechanisms underlying immobilization-induced muscle pain in rats.

We investigated the mechanisms underlying immobilization-induced muscle pain in rats. In rat skeletal muscle, pressure pain threshold (PPT) of the gastrocnemius muscle was measured, and nerve growth factor (NGF) level, peripheral nerve fiber density, macrophage number, and interleukin-1β (IL-1β) mRNA expression were examined. An NGF receptor inhibitor was injected intramuscularly to assess the relationship between PPT and NGF levels. Immobilization resulted in a decrease in PPT and increases in NGF level, C-fiber density, M1 macrophage number, and IL-1β mRNA expression. Injection of NGF receptor inhibitor reversed the decrease in PPT. NGF upregulation may be a major contributor to immobilization-induced muscle pain. The increases in C-fiber density, M1 macrophage number, and IL-1β mRNA expression may be related to immobilization-induced muscle pain.

Pressure pain thresholds in children before and after surgery: a prospective study.

Background and aims This prospective study aimed to assess pressure pain thresholds (PPTs) by pressure algometry and the correlation to postoperative pain in children undergoing orthopaedic surgery. We hypothesized, that the PPTs would decline immediately after elective orthopaedic surgery and return to baseline values at follow-up. Methods Thirty children aged 6-16 years were included. PPTs and intensity of pain (Numerical Rating Scale, NRS) were assessed 3-6 weeks before surgery (baseline), 1-2 h before surgery (Day 0), the first postoperative day (Day 1) and 6-12 weeks after surgery (Follow-up). Results A significant difference of PPTs between the four assessments was seen using the Friedman test for detecting differences across multiple tests and Wilcoxon signed-rank test with a Bonferroni adjustment. The changes in PPTs between baseline (PPTcrus = 248 kPa, PPTthenar = 195 kPa) and day 1 (PPTcrus = 146 kPa, PPTthenar = 161 kPa) showed a decline of PPTs as hypothesized (Zcrus = 2.373, p = 0.018; Zthenar = 0.55, p = 0.581). More surprisingly, a significant decrease in PPTs between baseline and day 0, just before surgery (PPTcrus = 171 kPa, PPTthenar = 179 kPa), was also measured (Zcrus = 2.475, p = 0.013; Zthenar = 2.414, p = 0.016). PPTs were positively correlated to higher age, weight and height; but not to NRS or opioid equivalent use. Conclusions Children undergoing orthopaedic surgery demonstrate significant changes in PPTs over time. The PPTs decrease significantly between baseline and day 0, further decreases the first day postoperatively and returns to baseline values at follow-up. This suggests that other factors than surgery modulate the threshold for pain. Implications Awareness of pressure pain thresholds may help identify children with affected pain perception and hence improve future pain management in children undergoing orthopaedic surgery. Factors as for example anticipatory anxiety, psychological habitus, expected pain, catastrophizing, distraction, physical activity, patient education and preoperative pain medication might play a role in the perception of pain and need further investigation.

Erratum to: Quantitative Sensory Testing in Patients with Multisomatoform Disorder with Chronic Pain as the Leading Bodily Symptom-a Matched Case-Control Study.

OBJECTIVE Chronic pain is a debilitating condition of multifactorial origin, often without physical findings to explain the presenting symptoms. Of the possible etiologies of persisting painful symptoms, somatoform disorders and functional somatic syndromes (FSS) are among the most challenging, with a prevalence of 8-20%. Many different somatoform disorders and FSS have overlapping symptoms, with pain being the most prevalent one. The concept of multisomatoform disorder (MSD) has been developed to acknowledge that fact. We hypothesized that the concept of MSD will be reflected in a distinct sensory profile of patients compared with healthy controls and possibly provide insight into the type and pathophysiology of the pain commonly experienced by patients. DESIGN We performed comprehensive quantitative sensory testing (QST) in 151 patients and 149 matched controls. RESULTS There were significant differences in the sensory profiles of patients compared with controls. Patients with MSD showed a combination of tactile and thermal hypesthesia combined with mechanical and cold hyperalgesia. This was true for measurements at test and control sites, with the exception of vibration detection threshold and mechanical pain threshold. Among the observed changes, a marked sensory loss of function, as evidenced by an increase in cold detection threshold, and a marked gain of function, as evidenced by a decrease of pressure pain threshold, were most notable. There was no evidence of concurrent medication influencing QST results. CONCLUSIONS The observed somatosensory profile of patients with MSD resembles that of patients suffering from neuropathic pain with evidence of central sensitization.

Quantitative Sensory Testing in Patients with Multisomatoform Disorder with Chronic Pain as the Leading Bodily Symptom-a Matched Case-Control Study.

Chronic pain is a debilitating condition of multifactorial origin, often without physical findings to explain the presenting symptoms. Of the possible etiologies of persisting painful symptoms, somatoform disorders and functional somatic syndromes (FSS) are among the most challenging, with a prevalence of 8-20%. Many different somatoform disorders and FSS have overlapping symptoms, with pain being the most prevalent one. The concept of multisomatoform disorder (MSD) has been developed to acknowledge that fact. We hypothesized that the concept of MSD will be reflected in a distinct sensory profile of patients compared with healthy controls and possibly provide insight into the type and pathophysiology of the pain commonly experienced by patients. We performed comprehensive quantitative sensory testing (QST) in 151 patients and 149 matched controls. There were significant differences in the sensory profiles of patients compared with controls. Patients with MSD showed a combination of tactile and thermal hypesthesia combined with mechanical and cold hyperalgesia. This was true for measurements at test and control sites, with the exception of vibration detection threshold and mechanical pain threshold. Among the observed changes, a marked sensory loss of function, as evidenced by an increase in cold detection threshold, and a marked gain of function, as evidenced by a decrease of pressure pain threshold, were most notable. There was no evidence of concurrent medication influencing QST results. The observed somatosensory profile of patients with MSD resembles that of patients suffering from neuropathic pain with evidence of central sensitization.

A new experimental model of muscle pain in humans based on short-wave diathermy.

Experimental models of pain in humans are crucial for understanding pain mechanisms. The most often used muscle pain models involve the injection of algesic substances, such as hypertonic saline solution or nerve growth factor or the induction of delayed onset muscle soreness (DOMS) by an unaccustomed exercise routine. However, these models are either invasive or take substantial time to develop, and the elicited level of pain/soreness is difficult to control. To overcome these shortcomings, we propose to elicit muscle pain by a localized application of short-wave diathermy (SWD). In this crossover study, SWD was administered to 18 healthy volunteers to the wrist extensor muscle group, with a constant stimulation intensity and up to 4min. Pressure pain threshold (PPT), pinprick sensitivity (PPS) and self-reported muscle soreness were assessed at baseline and at 0, 30 and 60min after application of SWD. SWD evoked localized muscle pain/soreness in the wrist extensor muscle group and a decrease of PPT in the treated arm compared with the control arm that lasted for at least 60min, reflecting ongoing hyperalgesia after SWD application. PPS was not significantly altered 30-60min following SWD, suggesting a minimal contribution from skin tissue to sustained hyperalgesia. SWD was able to elicit muscle soreness and hyperalgesia up to 60min after its application. Thus, this new model represents a promising tool for investigating muscle pain in humans. This study presents an experimental model to elicit sustained muscle pain based on short-wave diathermy. The main advantages of the model are its noninvasiveness, the possibility to control stimulation parameters in a reliable way and the convenience of the time frame in which pain and hyperalgesia are developed.

No difference in pressure pain threshold and temporal summation after lumbar spinal manipulation compared to sham: A randomised controlled trial in adults with low back pain

BackgroundChanges in quantitative sensory tests have been observed after spinal manipulative therapy (SMT), particularly in pressure pain thresholds (PPT) and temporal summation (TS). However, a recent systematic review comparing SMT to sham found no significant difference in PPT in patients with musculoskeletal pain. The sham-controlled studies were generally low quality, and conclusions about other quantitative sensory tests could not be made. ObjectivesWe aimed to perform a sham-controlled study with the specific objective of investigating changes in PPT and TS short-term after lumbar SMT compared to sham manipulation in people with low back pain. MethodsThis was a double-blind randomised controlled trial comparing high-velocity low-amplitude lumbar SMT against sham manipulation in participants with low back pain. Primary outcome measures were PPT at the calf, lumbar spine and shoulder, and TS at the hands and feet. These were measured at baseline, then immediately, 15 min and 30 min post-intervention. ResultsEighty participants (42 females) were included in the analyses (mean age 37 years), with 40 participants allocated to each intervention group. Significant between-group differences were only observed for calf PPT, which could be explained by a decrease in PPT (increased sensitivity) after SMT and an increase after sham. Feet TS decreased significantly over time after both SMT and sham, and any other changes over time were inconsistent. ConclusionsOur results suggest that lumbar SMT does not have a short-term hypoalgesic effect, as measured with PPT and TS, when compared to sham manipulation in people with low back pain.

Delayed-Onset Muscle Soreness and Topical Analgesic Alter Corticospinal Excitability of the Biceps Brachii.

The interactive effect of delayed-onset muscle soreness (DOMS) and a topical analgesic on corticospinal excitability was investigated. Thirty-two participants completed Experiments A (no DOMS) and B (DOMS). For each experiment, participants were randomly assigned to two groups: 1) topical analgesic gel (topical analgesic, n = 8), or 2) placebo gel (placebo, n = 8) group. Before the application of gel (pregel), as well as 5, 15, 30, and 45 min postgel, motor-evoked potential (MEP) area, latency, and silent period, as well as cervicomedullary MEP and maximal compound motor unit action potential areas and latencies were measured. In addition, pressure-pain threshold (PPT) was measured pre-DOMS and at the same timepoints in experiment B. In experiment A, neither group showed a significant change for any outcome measure. In experiment B, both groups exhibited a significant decrease in PPT from pre-DOMS to pregel. After the application of topical analgesic, but not placebo, there was a significant increase in PPT at 45 min postgel, respectively, compared with pregel and a main effect of time for the silent period to increase compared with pregel. Participants with DOMS had reduced MEP and cervicomedullary MEP areas and increased corticospinal silent periods compared with those who did not have DOMS. These findings suggest that DOMS reduced corticospinal excitability and after the administration of menthol-based topical analgesic, there was a reduction in pain, which was accompanied by increased corticospinal inhibition.

Effect of Low-Volume High-Intensity Interval Exercise and Continuous Exercise on Delayed-Onset Muscle Soreness in Untrained Healthy Males.

Farias Junior, LF, Browne, RAV, Frazão, DT, Dantas, TCB, Silva, PHM, Freitas, RPA, Aoki, MS, and Costa, EC. Effect of low-volume high-intensity interval exercise and continuous exercise on delayed-onset muscle soreness in untrained healthy males. J Strength Cond Res 33(3): 774-782, 2019-The aim of this study was to compare the effect of a single session of a low-volume high-intensity interval exercise (HIIE) and a continuous exercise (CE) on the magnitude of delayed-onset muscle soreness (DOMS) in untrained healthy males. Fifteen participants (25.1 ± 4.4 years) completed 2 experimental sessions in a randomized order: (a) low-volume HIIE: 10 × 60 seconds at 90% of maximal velocity (MV) interspersed with 60 seconds of active recovery at 30% of MV and (b) CE: 20 minutes at 60% of MV. Pressure-pain threshold (PPT), pressure-pain tolerance (PPTol), and perceived pain intensity (PPI) were assessed in the rectus femoris, biceps femoris, and gastrocnemius before and 24 hours after exercise. There was a decrease of PPT in the rectus femoris (-0.5 kg·cm) and PPTol in the gastrocnemius (-1.4 kg·cm) and an increase of PPI in the rectus femoris (14.4 mm) and in the biceps femoris (11.7 mm) 24 hours after the low-volume HIIE session (p ≤ 0.05). There was a decrease of PPT (rectus femoris: -0.8 kg·cm; biceps femoris: -0.5 kg·cm; gastrocnemius: -0.9 kg·cm) and PPTol (rectus femoris: -1.9 kg·cm; biceps femoris: -2.7 kg·cm; gastrocnemius: -1.6 kg·cm) and an increase of PPI (rectus femoris: 8.1 mm; biceps femoris: 10.3 mm; gastrocnemius: 17.5 mm) in all muscles 24 hours after the CE session (p ≤ 0.05). No difference was observed between HIIE and CE sessions in any DOMS-related parameter (p > 0.05). In conclusion, a single session of low-volume HIIE and CE elicited a similar mild DOMS 24 hours after exercise in untrained healthy males.

From acute to persistent low back pain: a longitudinal investigation of somatosensory changes using quantitative sensory testing-an exploratory study.

Chronic low back pain (LBP) is commonly associated with generalised pain hypersensitivity. It is suggested that such somatosensory alterations are important determinants for the transition to persistent pain from an acute episode of LBP. Although cross-sectional research investigating somatosensory function in the acute stage is developing, no longitudinal studies designed to evaluate temporal changes have been published. This exploratory study aimed to investigate the temporal development of somatosensory changes from the acute stage of LBP to up to 4 months from onset. Twenty-five people with acute LBP (<3 weeks' duration) and 48 pain-free controls were prospectively assessed at baseline using quantitative sensory testing with the assessor blinded to group allocation, and again at 2 and 4 months. Psychological variables were concurrently assessed. People with acute LBP were classified based on their average pain severity over the previous week at 4 months as recovered (≤1/10 numeric rating scale) or persistent (≥2/10 numeric rating scale) LBP. In the persistent LBP group, (1) there was a significant decrease in pressure pain threshold between 2 and 4 months (P < 0.013), and at 4 months, pressure pain threshold was significantly different from the recovered LBP group (P < 0.001); (2) a trend towards increased temporal summation was found at 2 months and 4 months, at which point it exceeded 2 SDs beyond the pain-free control reference value. Pain-related psychological variables were significantly higher in those with persistent LBP compared with the recovered LBP group at all time points (P < 0.05). Changes in mechanical pain sensitivity occurring in the subacute stage warrant further longitudinal evaluation to better understand the role of somatosensory changes in the development of persistent LBP. Pain-related cognitions at baseline distinguished persistent from the recovered LBP groups, emphasizing the importance of concurrent evaluation of psychological contributors in acute LBP.

The effects of dry needling and radial extracorporeal shockwave therapy on latent trigger point sensitivity in the quadriceps: A randomised control pilot study

ObjectivesLatent myofascial trigger points (TrP) can alter joint kinematics, reduce strength and alter activation patterns, affecting athletic performance. TrP sensitivity can be measured with the pressure pain threshold (PPT). Dry needling (DN) has been used to treat latent TrPs, but may cause post-needling soreness. Radial extracorporeal shockwave therapy (rESWT) could be used as an alternative to DN during heavy training or competition. MethodsAfter baseline measures, 21 recreational athletes were split into three groups: DN, rESWT or control group, and were treated for three sessions in one week. Follow-up outcome sessions were conducted two to four and seven days after the last treatment. TrP sensitivity was measured using the PPT. ResultsThere was a groupXtime interaction for the PPT (p < 0.05). After a decrease in PPT during treating, there was a significant increase (p < 0.05) in PPT for the DN group (12.92%). The rESWT group also significantly (p < 0.05) increased (13.26%), but did not show any post-treatment soreness during the treatment phase. There was no difference in the PPT in the control group during any session. ConclusionDN is effective for increasing PPT of latent TrPs, but can be associated with post-treatment soreness. rESWT is as effective, but without the post-treatment soreness. Future studies should include treating multiple TrPs in the lower kinetic chain as well as measuring muscle activation and joint function. Furthermore, consideration for the current training load and up-coming competition is needed. Optimum timing and longer follow-up periods of such interventions should be explored. Level of evidence2b. SummaryTreating latent TrPs in the lower kinetic chain may improve muscle activation. Unlike DN, rESWT does not cause post- treatment soreness. Consideration of training load and up-coming competition is needed to deliver the optimum treatment strategy for athletes with latent TrPs.

Short-term effects of kinesio taping on trigger points in upper trapezius and gastrocnemius muscles

BackgroundKinesio taping is a possible therapeutic modality for myofascial pain, nevertheless, very scarce research has been performed on this subject. ObjectiveTo evaluate the immediate and short-term effect of kinesio taping application on myofascial trigger points (MTrPs) and pressure pain thresholds (PPTs) in the upper trapezius and gastrocnemius muscles. MethodsTwo randomized, single-blinded, controlled trials were simultaneously executed on the upper trapezius and gastrocnemius muscles. Different participants in each study were randomly assigned to an active intervention (N = 15) or control (N = 15) group. Kinesio taping was applied on the gastrocnemius or upper trapezius muscles by positioning three “I” strips in a star shape (tension on base) directly above the MTrPs in the active intervention group and a few centimeters away from the MTrPs in the controls. ResultsThe second evaluation on both sides showed lower PPT values than the first evaluation in the control group, denoting that the spots were more sensitive. The third evaluation showed even lower values. The active intervention group showed a contralateral side pattern similar to the controls. However, on the side of the kinesio taping application, the PPT values of the second evaluation were higher (the spots were less sensitive) and after 24 h returned to the original values. The difference between the PPT measurements on the MTrPs’ side of the active intervention group vs. the controls (time-group interaction) was significant (F (2,56) = 3.24, p = 0.047). ConclusionsWe demonstrated that a kinesio taping application positioned directly above the MTrPs may prevent an increase in sensitivity (decrease in PPT) immediately after application and prevent further sensitization up to 24 h later. The fact that two different muscles were similarly affected by the kinesio taping application, confirmed that the results were not in error. Further studies are needed to directly test the effect of a kinesio taping application on post-treatment soreness.

In patients with fibromyalgia, there are 18 tender points that are more sensitive than in healthy subjects

Fibromyalgia (FM) is a syndrome whose main symptoms include chronic fatigue, extensive muscle pain and a decrease in pressure pain thresholds (PPT). The Fibromyalgia Impact Questionnaire (FIQ) is a valid and reliable tool that reflects the impact of the disease on the quality of life of patients with FM. Our goal was two-fold: – to compare the PPT of 18 points between healthy subjects and fibromyalgia patients; – to compare the FIQ score with the mean of the PPT. The sample of the population consisted of two groups, 10 patients with FM and 15 healthy subjects (control group). The PPT was determined with an Algometer ® . We used an algorithm to determine order of measure of PPT. We applied increased pressure until the subject felt pain and pressed the button. We tested the 18 points (9 pairs: Occiput, low cervical, trapezius, supraspinatus second rib, lateral epicondyle, gluteal, greater knee) three times. Then, the subjects with FM completed the FIQ and obtained a score of 0 to 100. The mean age of the FM and control groups are 57.4 and 48.8 years old respectively ( P > 0.05). The FIQ score in FM group was 58 ± 12 (M ± SD). For all of the 18 tender points tested, patients with FM showed lower PPT that healthy participants (129 ± 58 vs. 349 ± 73 Kpa, P < 0.001). Patients with FM had PPT between 0.8 (second rib) and 1.7 kg/cm 2 (trochanter), whereas in healthy subjects, they were between 2.8 (occiput) and 4.4 kg/cm 2 (great trochanter). Furthermore, we did not find any significant correlation between the score of the FIQ and the mean PPT of the patients with FM ( r > –0.648; P = 0.07). We confirmed the data from the literature, that the PPT is lower in patients with fibromyalgia. Nevertheless, the presence of PPT less than 400 Kpa (4 kg/cm 2 ) in healthy subjects calls into question this threshold. However, more subjects would be required to confirm this trend and to show a correlation between the FIQ score and the PPT of fibromyalgia subjects.

The interaction between NGF-induced hyperalgesia and acid-provoked pain in the infrapatellar fat pad and tibialis anterior muscle of healthy volunteers.

Tissue pH is lowered in inflamed tissues, and the increased proton concentration activates acid-sensing ion channels (ASICs), contributing to pain and hyperalgesia. ASICs can be upregulated by nerve growth factor (NGF). The aim of this study was to investigate two new human experimental pain models combining NGF- and acid-induced pain in a randomized, controlled, double-blind study. In experiment 1, volunteers (N=16) received an injection of either NGF or isotonic saline in each infrapatellar fat pad (IFP). One day after 5mL of phosphate-buffered acidic saline was infused into each IFP at a rate of 20mL/h. In experiment 2, the tibialis anterior (TA) muscle of additional volunteers (N=16) was examined, following the same procedure except that the volume and infusion rate of acid were different (10mL, 30mL/h). Continuous pain ratings were recorded during and after acid infusions. In addition, soreness scores on a Likert scale and pressure pain thresholds (PPTs) were assessed. The PPT of the IFP was significantly decreased at the NGF injection site on day 1, but acid-provoked pain ratings and the change in PPT from pre- to postinfusion between the knees were similar. In the muscle pain model, local mechanical hyperalgesia developed 3h after the NGF injection and a significant additional decrease in PPT was found after acid infusion compared to preinfusion. NGF sensitization in the IFP was not facilitated by acid, whereas an acid-provoked enhancement of muscle hyperalgesia was found. NGF sensitization of adipose tissue responds differently to acid provocation compared to muscle tissue. Quantification of two novel pain models combining NGF and acid. Hyperalgesia developed after NGF injection in the infrapatellar fat pad, but it was not facilitated by acid provocation. Contrary, NGF-induced hyperalgesia in muscle tissue was enhanced by acid.

Parecoxib increases muscle pain threshold and relieves shoulder pain after gynecologic laparoscopy: a randomized controlled trial.

ObjectivesPostlaparoscopic shoulder pain (PLSP) remains a common problem after laparoscopies. The aim of this study was to investigate the correlation between pressure pain threshold (PPT) of different muscles and PLSP after gynecologic laparoscopy, and to explore the effect of parecoxib, a cyclooxygenase-2 inhibitor, on the changes of PPT.Materials and methodsThe patients were randomly allocated into two groups; group P and group C. In group P, parecoxib 40 mg was intravenously infused at 30 minutes before surgery and 8 and 20 hours after surgery. In group C, normal saline was infused at the corresponding time point. PPT assessment was performed 1 day before surgery and at postoperative 24 hours by using a pressure algometer at bilateral shoulder muscles (levator scapulae and supraspinatus) and forearm (flexor carpi ulnaris). Meanwhile, bilateral shoulder pain was evaluated through visual analog scale score at 24 hours after surgery.ResultsPreoperative PPT level of the shoulder, but not of the forearm, was significantly and negatively correlated with the intensity of ipsilateral PLSP. In group C, PPT levels of shoulder muscles, but not of forearm muscles, decreased after laparoscopy at postoperative 24 hours. The use of parecoxib significantly improved the decline of PPT levels of bilateral shoulder muscles (all P<0.01). Meanwhile, parecoxib reduced the incidence of PLSP (group P: 45% vs group C: 83.3%; odds ratio: 0.164; 95% confidence interval: 0.07–0.382; P<0.001) and the intensity of bilateral shoulder pain (both P<0.01).ConclusionPreoperative PPT levels of shoulder muscles are closely associated with the severity of shoulder pain after gynecologic laparoscopy. PPT levels of shoulder muscles, but not of forearm muscles, significantly decreased after surgery. Parecoxib improved the decrease of PPT and relieved PLSP.

Transcranial direct current stimulation and exercises for treatment of chronic temporomandibular disorders: a blind randomised‐controlled trial

To evaluate the effect of adding transcranial direct current stimulation (tDCS) to exercises for chronic pain, dysfunction and quality of life in subjects with temporomandibular disorders (TMD). Participants were selected based on the RDC/TMD criteria and assessed for pain intensity, pressure pain threshold over temporomandibular joint and cervical muscles and quality of life. After initial assessment, all individuals underwent a 4-week protocol of exercises and manual therapy, together with active or sham primary motor cortex tDCS. Stimulation was delivered through sponge electrodes, with 2 mA amplitude, for 20 min daily, over the first 5 days of the trial. A total of 32 subjects (mean age 24.7 ± 6.8 years) participated in the evaluations and treatment protocol. Mean pain intensity pre-treatment was 5.5 ± 1.4 for active tDCS group, and 6.3 ± 1.2 for sham tDCS. Both groups showed a decrease in pain intensity scores during the trial period (time factor--F(4.5,137.5) = 28.7, P < 0.001; group factor--F(1.0,30.0 = 7.7), P < 0.05). However, there were no differences between the groups regarding change in pain intensity (time*group interaction--F(4.5,137.5) = 1.5, P = 0.137). This result remained the same after 5 months (t-test t = 0.29, P > 0.05). Pressure pain thresholds decrease and improvement in quality of life were also noticeable in both groups, but again without significant differences between them. Absolute benefit increase was 37.5% (CI 95%: -15.9% to 90.9%), and number needed to treat was 2.66. This study suggests that there is no additional benefit in adding tDCS to exercises for the treatment of chronic TMD in young adults.