Lower Pressure Pain Thresholds Research Articles

Altered pain sensitivity in elderly women with chronic neck pain.

BackgroundAge-related changes occur in both the peripheral and central nervous system, yet little is known about the influence of chronic pain on pain sensitivity in older persons. The aim of this study was to investigate pain sensitivity in elders with chronic neck pain compared to healthy elders.MethodsThirty elderly women with chronic neck pain and 30 controls were recruited. Measures of pain sensitivity included pressure pain thresholds, heat/cold pain thresholds and suprathreshold heat pain responses. The pain measures were assessed over the cervical spine and at a remote site, the tibialis anterior muscle.ResultsElders with chronic neck pain had lower pressure pain threshold over the articular pillar of C5-C6 and decreased cold pain thresholds over the cervical spine and tibialis anterior muscle when compared with controls (p < 0.05). There were no between group differences in heat pain thresholds and suprathreshold heat pain responses (p > 0.05).ConclusionThe presence of pain hypersensitivity in elderly women with chronic neck pain appears to be dependent on types of painful stimuli. This may reflect changes in the peripheral and central nervous system with age.

Central sensitization and changes in conditioned pain modulation in people with chronic nonspecific low back pain: a case-control study.

Quantitative sensory testing is widely used in human research to investigate the state of the peripheral and central nervous system contributions in pain processing. It is a valuable tool to help identify central sensitization and may be important in the treatment of low back pain. The aim of this study was to evaluate changes in local and segmental hypersensitivity and endogenous pain inhibition in people with chronic nonspecific low back pain. Thirty patients with chronic low back pain and thirty healthy subjects were studied. Pressure pain thresholds (PPTs) were measured from the lumbar region and over the tibialis anterior muscle (TA). A cold pressor test was used to assess the activation of conditioned pain modulation (CPM), and PPTs in the lumbar region were recorded 30s after immersion of participant's foot in a bucket with cold water. People with chronic low back pain have significantly lower PPT than controls at both the lumbar region [89.5kPa (mean difference) 95% CI 40.9-131.1kPa] and TA [59.45kPa (mean difference) 95% CI 13.49-105.42kPa]. During CPM, people with chronic low back pain have significantly lower PPT than controls in lumbar region [118.6kPa (mean difference) 95% CI 77.9-159.2kPa]. Women had significantly lower PPTs than men in both lumbar region [101.7kPa (mean difference) 95% CI 37.9-165.7kPa] and over the TA [189.7kPa (mean difference) 95% CI 14.2-145.2kPa]. There was no significant difference in PPTs in men between healthy controls and those with low back pain, suggesting the significant differences are mediated primarily by difference between women.

The role of sleep in pain and fibromyalgia.

Fibromyalgia is a common cause of chronic widespread pain, characterized by reduced pressure pain thresholds with hyperalgesia and allodynia. In addition to pain, common symptoms include nonrestorative sleep, fatigue, cognitive dysfunction, stiffness and mood disturbances. The latest research indicates that the dominant pathophysiology in fibromyalgia is abnormal pain processing and central sensitization. Neuroimaging studies have shown that patients with fibromyalgia have similar neural activation to healthy age-matched and gender-matched individuals; however, they have a lower pressure-pain threshold. Polysomnography data has demonstrated that these patients have reduced short-wave sleep and abnormal α-rhythms, suggestive of wakefulness during non-REM (rapid eye movement) sleep. Sleep deprivation in healthy individuals can cause symptoms of fibromyalgia, including myalgia, tenderness and fatigue, suggesting that sleep dysfunction might be not only a consequence of pain, but also pathogenic. Epidemiological studies indicate that poor sleep quality is a risk factor for the development of chronic widespread pain among an otherwise healthy population. Mechanistically, sleep deprivation impairs descending pain-inhibition pathways that are important in controlling and coping with pain. Clinical trials of pharmacological and nonpharmacological therapies have shown that improving sleep quality can reduce pain and fatigue, further supporting the hypothesis that sleep dysfunction is a pathogenic stimulus of fibromyalgia.

MTPs are a peripheral source of nociception.

Quintner and Cohen have challenged the existence of myofascial trigger points ⇓. However, there is strong evidence that myofascial trigger points (MTPs) are a peripheral source of nociception, and act as ongoing nociceptive stimuli contributing to pain propagation and widespread pain ⇓. Pressure pain thresholds (PPTs) measurement applied to different locations over the muscles shows that the sites with the lowest PPT corresponding to the locations of MTPs, indicating that muscle nociceptors are sensitized. The sensitized nociceptors lead to an increased neuronal firing. In addition to the nociceptor sensitization, non-nociceptors (mainly the large diameter muscle afferents) may also via central neuronal reorganisation and sensitization contribute to pain perception generated from MTPs. Thus, local pain and tenderness at MTPs are largely due to nociceptor sensitization most likely with a lesser contribution from non-nociceptor activation ⇓. The study by Freeman et al. ⇓, found that anesthetizing of painful trigger points, provokes a remarkably rapid change in central sensitization symptoms (measuring PPTs in a site far away from the areas that had been infiltrated) due to the reduced nociceptive drive needed for maintaining central sensitization. Why such focal pain generators persist and remain active after a reasonable healing period for soft tissue remains unclear. The …

Toll-like receptor 4 and comorbid pain in Interstitial Cystitis/Bladder Pain Syndrome: a multidisciplinary approach to the study of chronic pelvic pain research network study.

Interstitial Cystitis/Bladder Pain Syndrome (IC/BPS) is a condition characterized by pelvic pain and urinary symptoms. Some IC/BPS patients have pain confined to the pelvic region, while others suffer widespread pain. Inflammatory processes have previously been linked to pelvic pain in IC/BPS, but their association with widespread pain in IC/BPS has not been characterized. Sixty-six women meeting criteria for IC/BPS completed self-report measures of pain as part of the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP), collected 3days of saliva for cortisol assays, and provided blood samples. Peripheral blood mononuclear cells (PBMCs) were stimulated with Toll-like Receptor (TLR) 2 and 4 agonists and cytokines were measured in supernatant; IL-6 was also measured in plasma. Associations between inflammatory variables and the likelihood of endorsing extra-pelvic pain, or the presence of a comorbid syndrome, were tested by logistic regression and General Linear Models, respectively. A subset of patients (n=32) completed Quantitative Sensory Testing. A one standard deviation increase in TLR-4 inflammatory response was associated with a 1.59 greater likelihood of endorsing extra-pelvic pain (p=.019). Participants with comorbid syndromes also had higher inflammatory responses to TLR-4 stimulation in PBMCs (p=.016). Lower pressure pain thresholds were marginally associated with higher TLR-4 inflammatory responses (p=.062), and significantly associated with higher IL-6 in plasma (p=.031). TLR-4 inflammatory responses in PBMCs are a marker of widespread pain in IC/BPS, and should be explored in other conditions characterized by medically unexplained pain.

Gender Differences in Pressure Pain Thresholds during Sustained Jaw Muscle Contraction

Purpose: To determine whether a fatiguing clench significantly affects the changes in pressure pain threshold (PPT) in men compared to women. Methods: The changes of PPTs from before to after a sustained clench in 12 men and 12 women were obtained. We used a decrease in median frequencies of surface electromyography (EMG) power spectra from the start to the end of the sustained clench as evidence of fatigue. Endurance time for the clench was used as a covariate. Results: The median frequencies decreased after the clench in both the anterior temporalis and masseter muscles, did not differ with the muscle or the gender of the subjects, and none of the interaction terms were significant. The PPTs were lower for women for both muscles, were decreased after the sustained clench, but failed to show the hypothesized gender by time interaction. Conclusions: Our results show that women have lower PPTs than men, but do not respond differently than men to jaw muscle fatigue.

Preoperative widespread pain sensitization and chronic pain after hip and knee replacement: a cohort analysis.

Chronic pain after joint replacement is common, affecting approximately 10% of patients after total hip replacement (THR) and 20% of patients after total knee replacement (TKR). Heightened generalized sensitivity to nociceptive input could be a risk factor for the development of this pain. The primary aim of this study was to investigate whether preoperative widespread pain sensitivity was associated with chronic pain after joint replacement. Data were analyzed from 254 patients receiving THR and 239 patients receiving TKR. Pain was assessed preoperatively and at 12 months after surgery using the Western Ontario and McMaster Universities Osteoarthritis Pain Scale. Preoperative widespread pain sensitivity was assessed through measurement of pressure pain thresholds (PPTs) at the forearm using an algometer. Statistical analysis was conducted using linear regression and linear mixed models, and adjustments were made for confounding variables. In both the THR and TKR cohort, lower PPTs (heightened widespread pain sensitivity) were significantly associated with higher preoperative pain severity. Lower PPTs were also significantly associated with higher pain severity at 12 months after surgery in the THR cohort. However, PPTs were not associated with the change in pain severity from preoperative to 12 months postoperative in either the TKR or THR cohort. These findings suggest that although preoperative widespread pressure pain sensitivity is associated with pain severity before and after joint replacement, it is not a predictor of the amount of pain relief that patients gain from joint replacement surgery, independent of preoperative pain severity.

Serotonin receptor gene (5HT-2A) polymorphism is associated with provoked vestibulodynia and comorbid symptoms of pain.

Provoked vestibulodynia (PVD) is a common type of dyspareunia among young women. The patho-physiology remains largely unclear. Women with PVD have general pain hypersensitivity and often report additional pain symptoms. Signs point towards PVD being a chronic pain disorder similar to other syndromes of longstanding pain, including a common comorbidity of anxiety and depression. Polymorphism in the serotonin receptor gene, 5HT-2A, has been associated with other chronic pain disorders such as fibromyalgia but has not been investigated in PVD patients. We aimed to investigate a possible contribution of polymorphism in the 5HT-2A gene to the etiology of PVD as well as a potential influence on pain sensitivity. In this case-control study 98 women with PVD and 103 healthy controls between 18 and 44 years and in the same menstrual cycle phase completed questionnaires and underwent quantitative sensory testing. Venous blood samples were collected for DNA isolation. Concomitant pain was reported, a bodily pain score was created and pressure pain thresholds (PPTs) on the arm, leg, and in the vestibule were measured. Intensity of coital pain was rated on a visual analog scale, range 0-100. The T102C (rs6313) and A-1438G (rs6311) single nucleotide polymorphisms (SNPs) in the 5HT-2A gene were analyzed. The probability of PVD was elevated in participants carrying the 1438G- and 102C-alleles of the 5HT-2A gene (OR 2.9). The G-/C- genotypes were also associated with more concomitant bodily pain in addition to the dyspareunia, but not with experimental PPTs or coital pain ratings. PVD patients reported more concomitant bodily pain and had lower PPTs compared with controls. The results indicate a contribution of alterations in the serotonergic system to the patho-genesis of PVD and gives further evidence of PVD being a general pain disorder similar to other chronic pain disorders.

The Interleukin-1α Gene C&gt;T Polymorphism rs1800587 is Associated With Increased Pain Intensity and Decreased Pressure Pain Thresholds in Patients With Lumbar Radicular Pain

Previous studies have suggested that many inflammatory cytokines, including interleukin (IL)-1α, may be associated with lumbar radicular pain after disk herniation. In the present study, we examined how variability of the IL-1α gene affects pain intensity and the pressure pain threshold (PPT) in patients with symptomatic disk herniation. A total of 121 patients with lumbar radicular pain due to disk herniation were recruited from Oslo University Hospital, Norway, and followed up at 6 weeks and 12 months. The primary outcome measures were pain intensity scores for the lower back and legs using a visual analog pain scale (VAS) and PPT for the gluteal muscles. Genotyping was carried out using a predesigned TaqMan assay for IL-1α rs1800587. The effect of the IL-1α genotype on the VAS and PPT was analyzed by repeated measure analyses of variance. The IL-1α gene C>T polymorphism rs1800587 affected VAS and PPT scores in patients with symptomatic disk herniation. Patients with the CT/TT genotype reported a higher VAS leg pain intensity (P=0.002) and also a lower PPT in the gluteal muscles (left P=0.016; right P=0.016) compared with patients with the CC genotype during 1 year of follow-up. The present data show that the IL-1α CT/TT genotype rs1800587 may be associated with increased pain intensity and corresponding reduced PPT during the first year after disk herniation.

Pain and pressure pain thresholds in adolescents with chronic fatigue syndrome and healthy controls: a cross-sectional study

ObjectivesAlthough pain is a significant symptom in chronic fatigue syndrome (CFS), pain is poorly understood in adolescents with CFS. The aim of this study was to explore pain distribution and...

Study of the trapezius muscle region pressure pain threshold and latency time in young people with and without depressed scapula

The scapula is stabilized in or moved to a certain position to coordinate shoulder function and achieve shoulder and arm movement during the athletic and daily activities. An alteration in the scapular position both at rest and during arm movements is commonly associated with shoulder injury or dysfunction. The purpose of this study was to assess the influence of the depressed scapular position using pressure pain threshold (PPT) and delayed muscle activation of the upper and middle trapezius muscles. The study included 20 subjects who were divided into normal shoulder (n = 12) and depressed shoulder (n = 8) group. PPT was measured in a relaxed position. Muscle activity was recorded using surface electromyography and by calculating each shrug's muscle latency time (MLT). The results revealed that the healthy young subjects with depressed scapular position had significantly lower PPT levels than those with normal scapular position both in the upper and middle trapezius muscle (P < 0.05). MLT of the upper trapezius was significantly delayed in both sides during the shoulder shrugs (P < 0.05).

The interleukin-1α gene C>T polymorphism rs1800587 is associated with increased pain intensity and decreased pressure pain thresholds in patients with lumbar radicular pain

Abstract Aims Previous studies have suggested that many inflammatory cytokines, including interleukin (IL)-1α, may be associated with lumbar radicular pain after disc herniation. In the present study, we examined how variability of the IL-1α gene affects pain intensity and the pressure pain threshold (PPT) in patients with symptomatic disc herniation. Methods A total of 121 patients with lumbar radicular pain due to disc herniation were recruited from Oslo University Hospital, Norway, and followed up at 6 weeks and 12 months. The primary outcome measures were pain intensity scores for the lower back and legs using a visual analog pain scale (VAS) and PPT for the gluteal muscles. Genotyping was carried out using a predesigned TaqMan assay for IL-1α rs1800587. The effect of the IL-1α genotype on the VAS and PPT was analyzed by repeated measure analyses of variance. Results The IL-1α gene C&gt;T polymorphism rs1800587 affected VAS and PPT scores in patients with symptomatic disc herniation. Patients with the CT/TT genotype reported a higher VAS leg pain intensity (p = 0.002) and also a lower PPT in the gluteal muscles (left p = 0.016; right p = 0.016) compared to patients with the CC genotype during 1 year of follow-up. Conclusions The present data show that the IL-1α CT/TT genotype rs1800587 may be associated with increased pain intensity, and corresponding reduced PPT during the first year after disc herniation.

A Comparison Pressure Pain Threshold in Pericranial and Extracephalic Regions in Children with Migraine

There is evidence that the pressure pain threshold (PPT) is reduced in children with migraine and that it varies according to age, sex, and region of the body. However, in view of the lack of consensus in the literature, the objective of the present study was to evaluate the PPT in children with migraine of both genders aged 6-12 years. Fifty children with migraine without aura and 50 children without headache were studied. The PPT was evaluated using an algometer at nine bilateral anatomical sites. Comparison of children with migraine to children without headache did not show differences in PPT, except for the points of insertion of occipital muscles and the anterior aspect of C5-C7, where the values were lower in the children with migraine. Analysis according to gender revealed that both girls and boys had a lower PPT in at least one region evaluated. Comparison of the PPTs between sites revealed that the pericranial and cervical regions showed a lower PPT than the extracephalic sites in children with migraine.

Chronic pain in patients with the hypermobility type of Ehlers–Danlos syndrome: evidence for generalized hyperalgesia

Background: The Ehlers-Danlos Syndrome (EDS) is one the most prevalent heritable connective tissue disorders. Generalized severe joint hypermobility, which is frequently associated with joint dislocations, chronic joint and limb pain, and premature osteoarthritis, are the dominant clinical manifestations of the hypermobility type of EDS (EDS-HT). Chronic widespread pain is highly present in this patient group, but up to now, evidence for generalized hyperalgesia is lacking. Several studies in chronic pain disorders examined whether central hyperexcitability could be existent by using algometry. Purpose: The primary objective of the study was to investigate whether pressure pain thresholds (PPTs) at both symptomatic and asymptomatic body areas differ in EDS-HT patients compared to healthy subjects. In addition, we examined the type of chronic pain EDS-HT patients experience. Methods: Twenty-three women with EDS-HT and 23 gender- and age-matched healthy controls participated. All subjects marked on Margolis Pain Diagram where they felt pain lasting longer than 24 hours in the past 4 weeks. Then, they completed several questionnaires assessing pain cognitions (Pain Catastrophizing Scale, Pain Vigilance and Awareness Questionnaire, Hospital Anxiety and Depression Scale), fatigue (Checklist Individual Strength subscale fatigue), disability (Health Assessment Questionnaire), and general health status (Short Form Health Survey-36), in order to take the possible influence of these factors on PPTs into account. Patients also completed the Pain Detect Questionnaire regarding the severity, course, quality and nature of the pain they experienced. Thereupon, a blinded researcher assessed PPTs at 14 body locations on the trunk and extremities. The pressure was gradually increased at a rate of 1kg/s until the subject indicated that the pain level has been reached. The threshold was determined as the mean of the 2 last values out of the 3 consecutive measurements. This method has been found to be efficient and reliable in the exploration of pathophysiological mechanisms involved in pain. PPTs were compared for the 2 complete groups. In addition, PPTs of patients and controls who did not report pain in a respective zone were compared. Results: The EDS-HT patient group demonstrated significantly lower PPTs compared to the control group for all zones. The mean (SD) PPT was 2.9 (1.62) kg/cm2 in the EDS-HT patients and 5.2 (1.88) kg/cm2 in the controls (P<0.001). Also at asymptomatic (pain-free) zones, EDS-HT patients systematically showed significantly lower pain thresholds compared to the healthy subjects. No confounding factors responsible for the observed differences could be revealed. According to the Margolis Pain Diagram, EDS-HT patients experienced pain on an average of 31% (±17.8) of their body surface, compared to 1% (±2.4) in the control subjects. Furthermore, approximately 40% of the patients presented with a nociceptive pain pattern, whereas in about 50% a predominantly neuropathic pain component was likely present. Conclusion: This study shows that several forms of pain coexist in EDS-HT which are likely the result of different pain-triggering mechanisms. The widespread pain lacking local distinction together with the lower PPTs in body zones outside and remote to the symptomatic zone provide evidence for the existence of generalized secondary hyperalgesia in patients with EDS-HT, which may represent the involvement of a sensitized central nervous system as an important mechanism in the chronic pain problems of this challenging patient group.

Short-Term Treatment with Parecoxib for Complex Regional Pain Syndrome: A Randomized, PlaceboControlled Double-Blind Trial

Background: Complex regional pain syndrome (CRPS) is characterized by signs and symptoms of peripheral inflammation, which leads to peripheral neural sensitization associated most frequently (in about 70%) with blunt pressure hyperalgesia. Therefore, we hypothesized that treatment of CRPS patients with a selective COX-2-inhibitor would alleviate the abnormally low pressure pain threshold (PPT) and reduce pain intensity and edema. Methods: Twenty patients with CRPS type I (n = 16) and II of the upper limb and abnormally low PPT were double-blind randomised into 2 groups of 10 patients each to receive a 2-day intravenous treatment of either 80 mg parecoxib per day (group I) or placebo (NaCl 0.9%, group II). Standardized quantitative sensory testing (QST) using the DFNS protocol was performed before and after treatment. Pain intensity (NRS 0 – 10); circumferences of the fingers II, IV, and V (mm); PPT (kPa, thenar/hypothenar); and adverse events were recorded daily. Statistics: Wilcoxon-test, Mann-Whitney-U-test, Friedman-test, Fisher-test, significance level: P &lt; 0.05. Study Design: Proof of concept trial performed in randomized, placebo-controlled, double blind style . Setting: Pain Management Center in Germany. Results: There were no group differences in PTT or other QST parameters. After treatment, PPT decreased insignificantly in group I (median [range]; before: 224.0 [121.0 – 52937] kPa, afterwards: 186.4 [101.4 – 526.5] kPa) and increased insignificantly in group II (before: 207.6 [170.0 – 320.5] kPa; afterwards: 235.4 [163.5 – 349.9] kPa). Pain scores and finger circumferences remained unchanged in both groups. Limitations: Due to difficulty in recruitment the trial was closed after inclusion of 20 patients. Conclusion: In the present proof-of-concept trial, short-term treatment with the selective COX2-inhibitor parecoxib influenced neither PPT nor edema or pain. COX-2 might be less important than previously assumed. However, the results are limited due to the small number of patients, short-term treatment, and focus on the PPT, which could have led to false negative results of the present study and covered the expected therapeutic effect. Key words: Parecoxib, complex regional pain syndrome, pressure pain threshold, pressure hyperalgesia, quantitative sensory testing, inflammation

Determination of a pressure pain threshold cut‐off value for the diagnosis of temporomandibular joint arthralgia

Temporomandibular joint (TMJ) disorders are divided by the American Academy of Orofacial Pain into five categories. The most common ones are joint pain, as arthralgia and joint disorders, as disc displacements. An important clinical presentation of arthralgia is the painful tenderness to manual palpation or decreased pressure pain threshold (PPT). The authors conducted a study to determine the appropriate PPT value to discriminate asymptomatic TMJ individuals from those with moderate to severe arthralgia. Forty-nine individuals was evaluated and divided into groups: TMJ arthralgia, asymptomatic disc displacement and control group. Magnetic resonance images were obtained for all the groups, and algometry was performed on the TMJ lateral pole. Patients with arthralgia filled out a visual analogue scale (VAS). anova test with 1% of significance analysed the data. Specificity, sensitivity and ROC curve were also determined. Arthralgia group had significant lower PPT (mean of 1.07 kgf cm(-2) ) than the others. Asymptomatic disc displacement group (mean of 1.64 kgf cm(-2) ) has shown significant lower PPT than the control (mean of 2.35 kgf cm(-2) ). 89.66% of specificity and 70% of sensitivity were obtained when 1.36 kgf cm(-2) was applied to the TMJ (ROC area = 0.90). This value was considered to be the most appropriate to detected moderate to severe TMJ arthralgia. Indeed, the presence of disc displacement seems to significantly decrease PPT levels in asymptomatic subjects. The PPT value of 1.36 kgf cm(-2) can be used in the calibration procedures of the professionals involved with temporomandibular disorders and orofacial pain.

Pressure pain threshold of the cervico‐facial muscles in healthy elderly people: the role of gender, age and dominance

The aim of this study was to assess the impact of age on pressure pain threshold (PPT) of cervico-facial muscles in healthy geriatric subjects and to investigate the role of gender and dominance on nociception. Musculo-skeletal pain is common in the elderly, but being subjective, it risks to be underdiagnosed and undertreated. A useful method for assessment of local pain is determining PPT through pressure algometry. Ageing process seems to increase PPTs, but reference values for the assessment of pain in geriatric subjects are lacking. In this study, PPTs in temporal muscle, masseter, sternocleidomastoid, occipital and splenius capitis of 97 healthy elderly subjects were measured using Fischer algometer. Participants were divided by age in four classes (years 65-69; 70-74; 75-79; ≥80). Women had lower PPTs in all muscles compared with men. Comparing PPTs obtained from the right and the left side, no significant differences were recorded neither in men nor in women. When dividing subjects by age class and education, in both genders no significant differences were observed in PPTs among the groups, neither in the right nor in the left sides. In conclusion, the present study reports reference PPT values for the cervico-facial muscles that can be applied to a population of healthy elderly subjects. After 65 years of age, further ageing does not influence PPTs in cervico-facial muscles whereas female gender has lower PPTs.

Higher serum S100B and BDNF levels are correlated with a lower pressure-pain threshold in fibromyalgia.

BackgroundFibromyalgia (FM) is conceptualized as a central sensitization (CS) condition, that presents high serum brain-derived neurotrophic factor (BDNF) and neuroglia activation. Although the S100B protein regulates neuroglia functions, it has been traditionally used as a proxy of central nervous system damage. However, neither BDNF nor S100B association with the clinical picture of FM has been elucidated. To explore their association with the pressure-pain threshold (PPT) in FM, we performed a cross-sectional study, including 56 females with confirmed FM aged 18–65 years. Linear regression models were used to adjust for potential confounding factors between serum BDNF, S100B and PPT.ResultsSerum BDNF and S100B were correlated (Spearman’s Rho = 0.29). Serum BDNF (log) and S100B (log) were correlated with the PPT (log) (Partial η2 = 0.129, P = 0.012 for the BDNF (log), and Partial η2 = 0.105, P = 0.025 for the S100B (log)). Serum BDNF (log) was inversely associated with PPT (log) (β = -1.01, SE = 0.41), age (β = -0.02, SE = 0.15) and obsessive compulsive disorder (β = -0.36, SE = 0.15), while serum S100B (log) was inversely associated with PPT (log) (β = -1.38, SE = 0.50), only.ConclusionsBoth neuroglia key mediators in the CS process were inversely correlated with the PPT. Serum assessment of BDNF and S100B deserve further study to determine its potential as a proxy for the CS spectrum in FM.

Sleep quality, arousal and pain thresholds in tension-type headache: A blinded controlled polysomnographic study

We aimed to compare subjective and objective sleep quality in tension-type headache (TTH) patients and to evaluate the relationship between sleep quality and pain thresholds (PT) in controls and TTH patients. A blinded cross-sectional study where polysomnography (PSG) and PT (to pressure, heat and cold) measurements were done in 20 patients with TTH (eight episodic (ETTH) and twelve chronic (CTTH) TTH) and 29 healthy controls. Sleep diaries and questionnaires were applied. TTH patients had more anxiety ( P = 0.001), insomnia ( P < 0.0005), daytime tiredness ( P < 0.0005) and reduced subjective sleep quality ( P < 0.0005) compared to healthy controls. Sleep diaries revealed more long awakenings in TTH ( P = 0.01) but no total sleep-time differences. TTH patients had more slow-wave sleep ( P = 0.002) and less fast arousals ( P = 0.004) in their PSGs. CTTH subjects had lower pressure PT ( P = 0.048) and more daytime sleepiness than the controls ( P = 0.039). Among TTH lower cold PT (CPT) correlated inversely with light sleep (N1) ( R = -0.49, P = 0.003) while slow arousals correlated inversely with headache-frequency ( R = -0.64, P = 0.003). We hypothesize that TTH patients need more sleep than healthy controls and might be relatively sleep deprived. Inadequate sleep may also contribute to increased pain sensitivity and headache frequency in TTH.

Strength gain through eccentric isotonic training without changes in clinical signs or blood markers

BackgroundLocalized exercises are widely used in rehabilitation processes. The predominant options are exercises with an emphasis on either concentric or eccentric contractions. Eccentric exercises promote greater strength gains compared to classical concentric stimuli, but can cause muscle damage. The aim of present study was to compare strength training composed of 10 sessions with progressive loads between groups with a predominance of concentric versus eccentric contraction through an analysis of isotonic strength, pressure pain threshold, creatine kinase, tumor necrosis factor-alpha and cortisol.MethodsOne hundred twenty male subjects were divided into four groups: C1 and E1 – single session of maximum strength with emphasis on concentric and eccentric contraction, respectively; C10 and E10 – 10 sessions with progressive loads from 80% to maximum strength with emphasis on concentric and eccentric contraction, respectively.ResultsIsotonic strength increased by 10% in E10 following the ten training sessions. C1 and E1 exhibited a lower pressure pain threshold 48 hours after the sessions in comparison to C10 and E10, respectively. Creatine kinase was increased in C1 in comparison to baseline, with significant differences (p ≤ 0.05) in comparison to E1 at 48 and 96 hours as well as C10 at 48, 72 and 96 hours. No significant differences were found in TNF-α or cortisol among the groups or evaluation times.ConclusionEccentric contraction training promotes functional adaptation. Moreover, both concentric and eccentric contraction training have a protective effect on the muscle in relation to a single session of maximum strength exercise.Trial registrationRBR-75scwh