Pressure Pain Threshold Values Research Articles

Experimental pain sensitivity in women with vestibulodynia: a pilot study

Objective: Investigate pain sensitivity in women with vestibulodynia using two experimental pain assessments outside the vulvar region: intramuscular infusion of an acidic phosphate buffer and pressure pain thresholds (PPTs) of the lower limb. Methods: Three women with a history of vestibulodynia (all 24 years old) participated after providing written informed consent. PPTs of the lower limb were assessed using a hand-held Somedic digital algometer (30 kilopascal (kPa)/sec) at baseline (pre-infusion) and during the intramuscular infusion. The acidic phosphate buffer (pH 5.2) was infused into the anterior tibialis muscle at a rate of 40 ml/hr for 15 min (10 ml total). Peak local (infusion site) and referred (ankle) pain ratings were assessed verbally, as well as vulvar pain at the time of the infusion (0 – 10 Borg Scale). Results: Peak local pain was higher in two of the three subjects (2.5, 4.0, 9.5) than the average pain ratings in 34 healthy age-matched (21 – 27 years old) women from our laboratory, mean 3.0/10 (standard deviation (SD) 2.2; range 0.5 to 10). Peak referred pain was also higher in the same two subjects (0, 4.25, and 7.5) than the average of the controls (mean 1.5; SD 1.8; range 0 – 9.0). Similarly, vulvar pain patients all exhibited greater mechanical pain sensitivity (lower PPT values) than the average of the healthy controls (mean [SD] 246.3 [101.7] kPa in patients vs. 431.3 [109.33] in controls). Conclusion: Preliminary data suggests women with vestibulodynia may exhibit greater generalized pain sensitivity to noxious stimuli than the general population of women.

Characteristic of the normal values of the pain threshold values in the dorsal region of the young women obtained by the pressure algometry method under different condition

The objective of the present study was to obtain the statistical characteristics of the individual pressure pain threshold (PPT) for the healthy women and patients presenting with minor disturbances of spinal motion segments (SMS) at the trigger points on the back. The secondary objective was to estimate the dependence of the PPT parameters on a variety of conditions. Two groups of female volunteers (students of the South Ural State Humanitarian Pedagogical University aged 19-21 years) were formed, one composed of the girls in the quiescent state (group 1, n=45), the other comprised of the girls in the state of emotional agitation and prepared for physical activity (group 2, n=105). Each group was split into two sub-groups depending on the presence or absence of complaints about the state of the SMS. PPT was evaluated in terms of kg/cm2 with the use of the Wagner FPX algometer (USA) at 3 paired paravertebral points localized at different levels: the second and third lumbar vertebrae (LII-LIII); the ninth-to-tenth thoracic vertebrae (DIХ-DХ), the seventh cervical, and first thoracic vertebrae (CVII-DI); as well as in pairs on the trapezius muscles in their upper parts. The height, weight, and body mass index of the participants in the study were measured. The PPTs values at the selected points on the back were log-normally distributed. The minimum values were measured on the trapezoidal muscles (about 2 kg/cm2) and the maximum ones in the lumbar spineregion (up to 7 kg/cm2). Complaints about the condition of SMS in group 1 were associated with the decrease of the PPT values at the paravertebral points on the neck and the lower back. No decrease of the PPT values in connection with the complaints was documented in the patients of group 2. The PPT values determined in the women of group 2 were statistically higher than in those of group 1 at all points studied and in all the subgroups; the differences ranged from 20% to 40%. The PPTs values at different points of the back correlated significantly between each other (Spearman correlation coefficient 0.6-0.9, p<0.001). In all the groups statistically significant asymmetry of the PPT values was documented (Kruskal-Wallis test, p<0.05); the right-side PPT values were lower than the left-side ones, with the difference amounting to 2-8%. The conditions of PPT measurements at the paravertebral points have a significant impact on the resultant values, being higher when the subject is ready for performing the physical exercises. The complaints about the state of the SMS are associated with the decrease in the PPT values that are lower on the right side of the body than on its left side.

Treatment of Myofascial Triggerpoints: A Comparison of “Spray and Stretch” and “Postisometric Relaxation”

Purpose: Referred pain from myofascial trigger points (MTrP) frequently can be found as the underlying condition in patients presenting with back pain, joint pain, or headache. The purpose of this trial was to compare the pain reduction of postisometric relaxation therapy (PIR) and spray and stretch therapy (SAS). Materials and Methods: Outpatients (24 female and 3 male) with at least one active MTrP were randomised to either SAS or PIR therapy. In both groups, every participant received 3 treatment sessions. The pressure pain threshold (PPT) was measured. Additionally, the pain level was rated by the patient using a visual analogue scale (VAS). The primary outcome was the difference in PPT at follow up after 3–4 weeks (t4) and time of randomisation (t0). As an exploratory data analysis PPT values and VAS ratings before and after each treatment session and VAS ratings at t0 and t4 have been evaluated. Results: The mean change in PPT was +22.1 kPa (SD 70.3 kPa) in the SAS group and −25.6 kPa (SD 80.5 kPa) in the PIR group. There was no significant difference between these mean values (p=0.1146). Hence no difference between these treatment options could be found. Also, the exploratory data analysis of PPT and VAS values did not suggest a difference between SAS and PIR treatments. In both groups, some patients worsened and some improved. In some cases PPT measurements and VAS ratings were inconsistent. Discussion: No difference was found between SAS and PIR, but the number of patients evaluated may have been too small to show an existing difference between the 2 treatment options. We included patients with acute myofascial pain as well as patients with chronic myofascial pain. They may react differently to treatment and should probably be evaluated separately. There may be a bias due to the change of the examiner in our trial. We can not explain the majority of women presenting with myofascial pain but this is consistent with former studies. Conclusions: Further research is necessary to reveal if either PIR or SAS therapy is more appropriate in terms of pain reduction. Patients with chronic pain and those with acute pain should be evaluated separately.

Somatosensory and Biomechanical Abnormalities in Females With Patellofemoral Pain.

Chronic patellofemoral pain (PFP) is a common orthopedic condition for which little is understood of the alterations in pain processing such as hyperalgesia, hypoesthesia, and the relationship of altered knee mechanics to hyperalgesia. We assessed pain, pressure pain thresholds (PPT), detection to light touch, and the relationship of pain and PPTs to knee abduction angle during a stair step down task between females with and without PFP. Twenty females diagnosed with PFP and 20 age-matched pain-free females participated in this study. Individuals underwent an instrumented assessment of knee mechanics during a stair step down task, PPT and detection of light touch over the center of the patella and lateral retinaculum, and PPT outside painful area over the right elbow. The PFP group had significantly lower PPT values at the patella (P=0.02), lateral retinaculum (P=0.001), and at the elbow (P=0.03). There was an elevated threshold to detect light touch over the center of their patella (P=0.04). A significant relationship between both pain (r=-0.49, P=0.03) and PPT values (r=0.65, P=0.004) to the frontal plane knee angle existed in the PFP group which was not present in the control group (r=-0.17, P=0.49) or in the elbow (r=-0.009, P=0.972). These results suggest that PFP is characterized by an increase in both localized and centralized pain sensitivity that is related to movement mechanics. Thus, PFP has both biomechanical, nociceptive components as well as inferred aspects of altered central sensitization.

Pressure thresholds and stiffness on the plantar surface of the human foot

A methodology to assess Pressure Discomfort Thresholds (PDT), Pressure Pain Thresholds (PPT) and tissue stiffness on the plantar surface of the foot was developed. Ten male and 10 female participants volunteered for the study. Foot landmarks were used to create a standardised grid-type template of 95 points. For each test point, PPT and PDT values were obtained, and stiffness was calculated for each of the 20 participants. Cluster analyses were performed to determine the regions of similarity for the three dependent variables, PPT, PDT and stiffness. Moran’s-I-index was used to determine the spatial auto correlations. The use of k-means clustering showed five distinct clusters while the three dependent variables showed strong correlations to each other. Morisita’s similarity index was used to check the similarity of the grid among all participants. Both male and female participants showed a Morisita’s index greater than 0.7 confirming the reliability of the foot template.Practitioner Summary: Pressure Discomfort thresholds (PPT), Pressure pain thresholds (PPT) and tissue stiffness were evaluated at 95 points on the plantar surface of the foot. The PPT and related PDT map are useful to design the footbeds of shoes. Based on the data collected, five distinct clusters of locations were identified.

Effectiveness of a Treatment Involving Soft Tissue Techniques and/or Neural Mobilization Techniques in the Management of Tension-Type Headache: A Randomized Controlled Trial

ObjectiveTo evaluate the effects of a protocol involving soft tissue techniques and/or neural mobilization techniques in the management of patients with frequent episodic tension-type headache (FETTH) and those with chronic tension-type headache (CTTH). DesignRandomized, double-blind, placebo-controlled before and after trial. SettingRehabilitation area of the local hospital and a private physiotherapy center. ParticipantsPatients (N=97; 78 women, 19 men) diagnosed with FETTH or CTTH were randomly assigned to groups A, B, C, or D. Interventions(A) Placebo superficial massage; (B) soft tissue techniques; (C) neural mobilization techniques; (D) a combination of soft tissue and neural mobilization techniques. Main Outcomes MeasuresThe pressure pain threshold (PPT) in the temporal muscles (points 1 and 2) and supraorbital region (point 3), the frequency and maximal intensity of pain crisis, and the score in the Headache Impact Test-6 (HIT-6) were evaluated. All variables were assessed before the intervention, at the end of the intervention, and 15 and 30 days after the intervention. ResultsGroups B, C, and D had an increase in PPT and a reduction in frequency, maximal intensity, and HIT-6 values in all time points after the intervention as compared with baseline and group A (P<.001 for all cases). Group D had the highest PPT values and the lowest frequency and HIT-6 values after the intervention. ConclusionsThe application of soft tissue and neural mobilization techniques to patients with FETTH or CTTH induces significant changes in PPT, the characteristics of pain crisis, and its effect on activities of daily living as compared with the application of these techniques as isolated interventions.

Comparison of ischemic compression and lumbopelvic manipulation as trigger point therapy for patellofemoral pain syndrome in young adults: A double-blind randomized clinical trial

To compare the effectiveness of ischemic compression (IC) directly to the vastus medialis obliquus (VMO) versus lumbopelvic manipulation (LPM) in improving pain, functional status and sensitivity to mechanical stimulation of the VMO trigger point in patients with patellofemoral pain syndrome (PFPS). 40 patients with unilateral PFPS aged 20-30 years were selected randomly among patients with unilateral PFPS referred to physical therapy clinics of Shiraz University of Medical Sciences in Shiraz, Iran, between March 2014 and July 2014. 30 young adults participated. Participants were blinded to treatment allocation, and 15 patients were allocated to either IC or LPM. Patients in both groups were treated in three sessions per week. IC consisted of three sets of continuous pressure applied for on the myofascial trigger point (MTrP) of VMO. LPM consisted of supine rotational glide manipulation of the ipsilateral lumbopelvic region of the involved knee. Numeric pain rating scale (VAS) for pain intensity, Kujala questionnaire for functional status, and pressure pain threshold (PPT) for sensitivity to mechanical stimulation. All three were recorded before treatment, 1 week, 1 month and 3 months after the last session. Both groups showed significant improvement (p<0.05, 95% confidence interval) in pain, functional status and PPT values. However, the IC group showed greater improvements, and outcome measures remained significantly better than in the LPM group during post-intervention follow-up. Both groups showed improvements throughout the study and follow-up period. However, the IC showed better short-term and long-term effectiveness than LPM for treating PFPS.

Painful temporomandibular disorders and central sensitization: implications for management—a pilot study

The objective was to investigate the presence of cutaneous allodynia and hyperalgesia in the trigeminal and extra-trigeminal areas, as a surrogate for central sensitization (CS), in women with a painful temporomandibular disorder (TMD) and without other painful conditions. Painful TMDs, depression, and non-specific physical symptoms (NSPS) were classified according to the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The amount of pain in the trigeminal and extra-trigeminal areas was determined using a visual analogue scale (0–100mm) after the application of a vibrotactile stimulus and assessment of the pressure pain threshold (PPT). Statistical tests (Fisher's, χ2, and Mann–Whitney) were performed, with a significance level of 5%. The sample comprised 45 women (mean age 37.5 years; 16 with a painful TMD) who were free of any headache, fibromyalgia, or other painful condition. Painful TMD was associated with higher pain sensitivity and lower PPT values in the trigeminal (P<0.01) and extra-trigeminal regions (P<0.01). The presence of depression contributed significantly to increased pain sensitivity. The presence of hyperalgesia and allodynia in both the trigeminal and extra-trigeminal regions among women with a painful TMD indicated the presence of CS. Changes involving the central nervous system should be considered during the evaluation and management of patients with a painful TMD.

Intra-session absolute and relative reliability of pressure pain thresholds in the low back region of vine-workers: ffect of the number of trials.

BackgroundPressure pain thresholds (PPT) are commonly used to quantify mechanical pain sensitivity of deep structures. Excellent PPT reliability has been previously reported among the low back of healthy subjects. However, there is a lack of studies assessing PPT over the low back of workers exposed to biomechanical risk factors of low back pain. Thus, the purpose of this study was threefold: (1) to evaluate the intra-session absolute and relative reliability as well as minimal detectable change (MDC) values of PPT within 14 locations covering the low back region of vine-workers and (2) to determine the number of trial required to ensure reliable PPT assessments and (3) to assess the effect of modifier factors such as gender, age, body mass index (BMI) and pain intensity on PPT reliability.MethodsTwenty-nine vine-workers voluntarily participated in this study. Twenty-two reported low intensity of low-back pain while seven were pain-free. PPTs were assessed among 14 anatomical locations in the lower back region. Three trials were performed on each location with an interval time of at least one minute. Reliability was assessed computing intraclass correlation coefficients (ICC), standard error of measurement (SEM) for all possible combinations between trials. Bland-Altman plots were also generated to assess potential bias in the dataset. Finally, a repeated measure analysis of variance (RM-ANOVA) with the number of trials used as within subject factor was performed on (1) PPT, (2) ICC and (3) SEM values.ResultsICC ranged from 0.86 to 0.99 for all anatomical locations and for all possible combinations between trials. SEM for comparison between trial 1–2, 2–3, 1–3 and, 1-2-3 ranged from respectively, 36.7–77.5, 27.8–77.7, 50–95.2 and, 39.3–80.8 kPa. ICC and SEM remained similar to the ones obtained for the entire population when taking modifier factors in consideration. The visual analysis of Bland-Altman plots suggested small measurement errors for all anatomical locations and for all possible combinations between trials.ConclusionsThe assessment of PPTs of the lower back among vine-workers was found to have excellent relative and absolute reliability. Moreover, reliable measurements can be equally achieved when using the mean of three PPT measurement or with the first one.

Metformin increases pressure pain threshold in lean women with polycystic ovary syndrome.

BackgroundDespite the strong preclinical rationale, there are only very few data considering the utility of metformin as a potential pain therapeutic in humans. The aim of this study was to determine the association between metformin therapy and pressure pain threshold (PPT) in lean women with polycystic ovary syndrome (PCOS). We hypothesized that metformin therapy in lean PCOS women increases PPT.Materials and methodsTwenty-seven lean PCOS women with free androgen index phenotype >5 and 18 lean healthy controls were enrolled in the study. Fifteen of the PCOS women were randomly assigned to be treated with metformin 1,500 mg daily for 6 months. PPT and plasma β-endorphin levels were measured in all women at the beginning of the study and after 6 months of observation.ResultsWe observed an increase in PPT values measured on deltoid and trapezius muscle in the PCOS with metformin group after 6 months of metformin administration (4.81±0.88 kg/cm2, P<0.001 on deltoid muscle, and 5.71±1.16 kg/cm2 on trapezius muscle). We did not observe any significant changes in PPT values in the PCOS without treatment group and in controls. We did not observe any significant changes in serum β-endorphin levels in any studied groups during the 6-month observation.ConclusionWe conclude that metformin therapy increases PPT in lean PCOS women, without affecting plasma β-endorphin concentration. Our results may suggest the potential role of metformin in pain therapy. We propose that larger, randomized studies on metformin impact on pain perception should be performed.

Pressure pain threshold is higher in hypertensive compared with normotensive older adults: A case-control study.

To establish whether there are differences in pain sensitivity between hypertensive and normotensive older adults. A cross-sectional case control study was carried out. A total of 72 older adults, 36 normotensive and 36 hypertensive, participated in the study. The pressure pain threshold (PPT) was assessed on seven points bilaterally in both groups by means of pressure algometry. Two-factor analysis of variance (anova) - group and sex - was carried out, and the magnitude of the differences was calculated using Cohen's index. The PPT values were higher in the group of hypertensive older adults compared with the normotensive older adults; that difference was significant (P < 0.05) for the following points: right and left trochanters, left trapezium, left L3/L4 and left anterior tibialis muscle, with both trochanter and left L3/L4 PPT showing moderate magnitude of the differences. The correlations shown among the PPT were stronger in the group of hypertensive older adults. Thus, hypoalgesia was more generalized among the hypertensive older adults compared with the normotensive older adults. Sex did not influence that difference, although the magnitude of the difference was greater among men compared with women. Hypoalgesia, as assessed by means of PPT, showed a relationship with arterial hypertension in older adults. The influence of sex on hypoalgesia shown by hypertensive individuals is controversial. Geriatr Gerontol Int 2017; 17: 967-972.

Manual trigger point therapy of shoulder pain : Randomized controlled study of effectiveness

Although chronic shoulder pain is highly prevalent and myofascial trigger points (mTrP) are thought to be found in the majority of patients with shoulder complaints, the influence on the pain mechanism remains unclear. There are only very few controlled clinical studies on the effects of manual trigger point compression therapy. This randomized controlled trial (RCT) compared the short-term effects of manual trigger point compression therapy (n= 6) with manual sham therapy (n= 6) in patients with unilateral shoulder pain due to myofascial syndrome (MFS). The measurement data were collected before and after two sessions of therapy. Pressure pain thresholds (PPT) of mTrP and symmetrically located points on the asymptomatic side were measured together with neutral points in order to detect a potential unilateral or generalized hyperalgesia. Additionally, the pain was assessed on a visual analog scale (VAS) at rest and during movement and the neck disability index (NDI) and disabilities of the arm, shoulder and hand (DASH) questionnaires were also completed and evaluated. Both treatment modalities led to a significant improvement; however, the manual trigger point compression therapy was significantly more effective in comparison to sham therapy, as measured by different parameters. The significant improvement of PPT values in the interventional group even at sites that were not directly treated, indicates central mechanisms in pain threshold modulation induced by manual compression therapy. The weaker but still measurable effects of sham therapy might be explained by the sham modality being a hands on technique or by sufficient stimulation of the trigger point region during the diagnostics and PPT measurements.

Pressure pain thresholds in patients with chronic nonspecific low back pain.

The lumbar back and hip muscles are important for a normal functioning of the human spine and they are considered to be of etiological significance in chronic nonspecific low back pain (nCLBP). Inactivity and a lower level of physical activity in patients with nCLBP may change muscle characteristics and may be associated with pain and disability. Pressure algometry has been found to be non-invasive, efficient and reliable in the exploration of physio-pathological mechanisms involved in muscle pain syndromes. The subjective characteristic of the pressure pain thresholds (PPTs) cannot be avoided once it is the very objective of the measurement, i.e. the minimum pain perceptible by the person, is a subjective factor. Most studies have revealed gender differences between PPTs, with females showing lower thresholds. to determine whether demographic variables and PPTs, are related pain intensity and a disability in patients with nCLBP. One hundred and twenty-four patients with nCLBP were included in the study. The Visual Analogue Scale (VAS) and the Roland-Morris Questionnaire for Low Back Pain (RM) were used to evaluate the intensity of pain and degree of disability. The PPT was performed from L1 up to S2 dermatomes, at the muscles over the Gluteus medius, minimus and maximus, including a point located at the level of the piriformis, at the Quadratus lumborum, at the Iliopsoas and points of reference located at the level of the L1 up to L5 ligaments. The pain intensity was assessed by visual analogue scale (VAS) and the lumbar function by Roland Morris questionnaire (RM). Multiple linear regression models were used for both the VAS and the RM. No significant differences were found between the PPTs measured at either left or right limb. The mean VAS value was 7.3 (± 1.5) and the RM score was 14.2 (± 5.3). The PPT-values showed significant negative correlations to the VAS and the RM. The highest correlation between the mean VAS and PPT-values were found at the level of the Gluteus medius (r= -0.34, p< 0.001), which was the only measurement correlated to the intensity of pain (r2 = 0.11, p< 0.001). The RM was correlated to the BMI, the level of education and the PPT values at the level of the Iliopsoas muscle and the L4-L5 supraspinous ligament. This study showed that most PPT values are correlated to the VAS and the RM. Nevertheless, the variability explained by PPT values and demographic characteristics was low for pain intensity and function.

Therapeutic effectiveness of a combined counseling plus stabilization appliance treatment for myofascial pain of the jaw muscles: A pilot study

Objective: This study aims to assess changes over time in pain intensity (VAS) and in pressure pain threshold (PPT) of the anterior temporalis and masseter muscles with a treatment protocol combining counseling and stabilization appliance as well as its effects on psychosocial factors.Methods: Twenty individuals with myofascial pain of jaw muscles lasting from at least six months were selected for an uncontrolled before-after study. Counseling was performed by giving information on myofascial pain and advice on self-management. Stabilization appliances were delivered one week after the first counseling session. A number of outcome variables (i.e. visual analogue scale [VAS], pain pressure threshold [PPT] and Research Diagnostic Criteria for Temporomandibular Disorders axis II [RDC/TMD]) were assessed at different evaluation points during a six-month follow-up. ANOVA for repeated measures and Pearson’s correlation test were used to evaluate changes in the outcome variables over time.Results: Compared to baseline data, a significant positive change was found at the 1st week, 1st, 3rd, and 6th month evaluations for VAS values (P < 0.0001) and at the 1st week, 3rd, and 6th month evaluations for PPT values (P < 0.05). RDC/TMD axis II values were significantly different (P < 0.05) from baseline to all evaluations points.Conclusion: The association of counseling and stabilization appliance is effective in the management of chronic myofascial pain of jaw muscles. Future controlled studies are required to get deeper into the assessment of the relative effectiveness of counseling and stabilization appliances.

Pain Threshold Tests in Patients With Heel Pain Syndrome.

Pressure pain threshold (PPT) is a useful tool for evaluating mechanical sensitivity in patients suffering from various musculoskeletal disorders. However, no previous study has investigated PPT in the heel of patients experiencing plantar heel pain syndrome (PHPS). The aim of this study was to compare PPT levels and topographic presentation of sensitivity in the heel of patients with PHPS and in healthy controls. The reliability of PPT testing in patients with PHPS was assessed for intra- and interrater recordings. The PPT levels of 40 feet in each group were then assessed on 5 predetermined sites in the heel using a standardized measurement protocol. Patient functional status (FS) as measured by the Foot & Ankle Computerized Adaptive Test was employed as an external reference. Multivariate analysis of covariance revealed no group differences for PPTs at all sites (P = .406). Age (P = .099) or BMI (P = .510) did not affect PPT values, although there was an effect on gender (P = .006). The analysis revealed significant differences between sites (P < .001) demonstrating a diverse topographic distribution. In the PHPS group, PPT levels at the anterior/medial, posterior/medial and central sites were significantly lower than at the posterior/lateral and anterior/lateral sites (P < .05). For the control group, PPT levels at the anterior/medial site were significantly lower than all other sites (P < .001). No significant differences were found between PPT of the PHPS patients and controls, therefore, PPT cannot be recommended as an assessment tool for these patients. The topographic distribution indicated low PPT levels at the anterior/medial area of the heel in patients with PHPS and controls. Level II, comparative study.

Effect of somatosensory amplification and trait anxiety on experimentally induced orthodontic pain.

The perception of pain varies considerably across individuals and is affected by psychological traits. This study aimed to investigate the combined effects of somatosensory amplification and trait anxiety on orthodontic pain. Five-hundred and five adults completed the State Trait Anxiety Inventory (STAI) and the Somatosensory Amplification Scale (SSAS). Individuals with combined STAI and SSAS scores below the 20th percentile (LASA group: five men and 12 women; mean age ± SD = 22.4 ± 1.3 yr) or above the 80th percentile (HASA group: 13 men and seven women; mean age ± SD = 23.7 ± 1.0 yr) were selected and filled in the Oral Behaviors Checklist (OBC). Orthodontic separators were placed for 5 d in order to induce experimental pain. Visual analog scales (VAS) were administered to collect ratings for occlusal discomfort, pain, and perceived stress. Pressure pain thresholds (PPT) were measured. A mixed regression model was used to evaluate pain and discomfort ratings over the 5-d duration of the study. At baseline, the LASA group had statistically significantly higher PPT values for the masseter muscle than did the HASA group. During the experimental procedure, the HASA group had statistically significantly higher discomfort and pain. A significant difference in pain ratings during the 5 d of the study was found for subjects in the HASA group. Higher OBC values were statistically significantly positively associated with pain. Somatosensory amplification and trait anxiety substantially affect experimentally induced orthodontic pain.

A comparison between different modes of real-time sonoelastography in visualizing myofascial trigger points in low back muscles

ObjectiveCurrently, there is a lack of objective means to quantify myofascial trigger points (MTrPs) and their core features. Our research compares (1) MTrPs and surrounding myofascial tissue using two-dimensional grayscale ultrasound (2DGSUS) and vibration sonoelastography (VSE); (2) the accuracy of both modes in visualizing MTrPs; (3) ‘active’ and ‘latent’ MTrPs, using VSE; and (4) the accuracy of both modes in visualizing deep and superficially located MTrPs.MethodsFifty participants with more than two MTrPs in their quadratus lumborum, longissimus thoracis, piriformis, and gluteus medius muscles were assigned to an active MTrP (low back pain) group or a latent (currently pain free) MTrP group. MTrP identification was based on their essential criteria. An electronic algometer measured repeatedly the tenderness of MTrPs with reference to pressure pain threshold values. A handheld vibrator was applied over MTrPs, while VSE and 2DGSUS readings were taken using an EUB-7500 ultrasound scanner.ResultsThere was a significant difference between MTrP strain and that of the immediately surrounding myofascial tissue, as measured using VSE (P = 0·001). VSE visualized all superficial and deep MTrPs with an accuracy of 100% (for both groups); the blinded results obtained using 2DGSUS achieved 33% and 35% accuracy, respectively. There was no significant difference found between the tissue strain ratios of active and latent MTrPs (P = 0·929).DiscussionSonoelastography can visualize superficial and deep MTrPs, and differentiate them from surrounding myofascial structure through tissue stiffness and echogenicity. VSE was more accurate than 2DGSUS in visualizing and imaging MTrPs.

Pain pressure threshold of a muscle tender spot increases following local and non-local rolling massage.

BackgroundThe aim of the present study was to determine the acute effect of rolling massage on pressure pain threshold (PPT) in individuals with tender spots in their plantar flexor muscles.MethodsIn a randomized control trial and single blinded study, tender spots were identified in 150 participants’ plantar flexor muscles (gastrocnemius or soleus). Then participants were randomly assigned to one of five intervention groups (n = 30): 1) heavy rolling massage on the calf that exhibited the higher tenderness (Ipsi-R), 2) heavy rolling massage on the contralateral calf (Contra-R), 3) light stroking of the skin with roller massager on the calf that exhibited the higher tenderness (Sham), 4) manual massage on the calf that exhibited the higher tenderness (Ipsi-M) and 5) no intervention (Control). PPT was measured at 30 s and up to 15 min post-intervention via a pressure algometer.ResultsAt 30 s post-intervention, the Ipsi-R (24 %) and Contra-R (21 %) demonstrated higher (p < 0.03) PPT values compared with Control and Sham. During 15 min post-intervention, PPT was higher (p < 0.05) following Ipsi-R (19.2 %), Contra-R (15.9 %) and Ipsi-M (10.9 %) compared with Control. There was no difference between the effects of three deep tissue massages (Ipsi-R, Ipsi-M and Contra-R) on PPT.DiscussionWhereas the increased PPT following ipsilateral massage (Ipsi-R and Ipsi-M) might be attributed to the release of fibrous adhesions; the non-localized effect of rolling massage on the contralateral limb suggests that other mechanisms such as a central pain-modulatory system play a role in mediation of perceived pain following brief tissue massage.ConclusionOverall, rolling massage over a tender spot reduces pain perception.Trial registrationClinicalTrials.gov (NCT02528812), August 19th, 2015.

Pressure pain thresholds assessed over temporalis, masseter, and frontalis muscles in healthy individuals, patients with tension-type headache, and those with migraine--a systematic review.

A systematic review was conducted to identify and summarize the available scientific literature addressing pressure pain threshold (PPT) values over the temporalis, masseter, and frontalis muscles in healthy humans, patients with tension-type headache (TTH), and those with migraine both in males and females. Six relevant medical databases for the literature search were included: PubMed, Web of Science, Cochrane, CINAHL, BioMed Central, and Embase. The search strategy was performed applying 15 keywords (eg, pressure pain threshold, temporalis muscle, tension type headache, pressure algometer) and their combinations. A total of 156 articles were identified, and 40 relevant articles were included. The main outcomes of the systematic review were extracted, and it was demonstrated that the PPT values in general were lower in patients compared with healthy subjects, and this was especially noted for temporalis in both females (migraine: 231.2 ± 38.3 kPa < TTH: 248.4 ± 39.3 kPa < healthy: 282.1 ± 70.8 kPa) and males (migraine: 225.5 ± 61.2 kPa < TTH: 264.2 ± 32.5 kPa < healthy: 314.8 ± 63.3 kPa). The masseter muscle seemed to be more sensitive than the other 2 muscles, in both females (healthy: masseter 194.1 ± 62.7 kPa < frontalis 277.5 ± 51.1 kPa < temporalis 282.1 ± 70.8 kPa) and males (healthy: masseter 248.2 ± 48.4 kPa < temporalis 314.8 ± 63.3 < frontalis 388 kPa). Females had lower PPT values than those of males in temporalis, masseter, and frontalis muscles. This work is the first to systematically review the scientific literature addressing PPT values over craniofacial muscles of healthy subjects, patients with TTH, and those with migraine to provide the PPT value ranges. Based on these findings, a set of guidelines was established to assist future studies including PPT assessments over craniofacial muscles.

Correlation between pressure pain threshold and pain intensity in patients with temporomandibular disorders who are compliant or non-compliant with conservative treatment

To investigate the correlation between pain measurements performed using a visual analogue scale (VAS) and pressure pain threshold (PPT) in individuals with temporomandibular disorders who underwent conservative treatment. This prospective study assessed 78 individuals diagnosed with myofascial pain, and the treatment consisted of counseling and self-care therapy sessions. Pain was assessed by means of a VAS and PPT at baseline (T0), after 15 to 30 days (T1), and after 75 to 90 days (T2). The participants were divided into two groups: "Compliant Group" and "Non-Compliant Group." The data were analyzed by means of Spearman's correlation test and Friedman's analysis of variance by ranks. Correlations were not identified between the VAS and PPT values at time points-T0, T1, or T2-in any group. Although, VAS and PPT represent subjective features, such as the perception of pain, the hypothesis that high pain intensity levels are equivalent to high pain sensitivity levels was not demonstrated.