Similarities in stress physiology among patients with chronic pain and headache disorders: evidence for a common pathophysiological mechanism?

How Can We Get to Equitable and Effective Postpartum Pain Control?

Postpartum pain is common, yet patient experiences and clinical management varies greatly. In the United States, pain-related expectations and principles of adequate pain management have been framed within established norms of Western clinical medicine and a biomedical understanding of disease processes. Unfortunately, this positioning of postpartum pain and the corresponding coping strategies and pain treatments is situated within cultural biases and systemic racism. This paper summarizes the history and existing literature that examines racial inequities in pain management to propose guiding themes and suggestions for innovation. This work is critical for advancing ethical practice and establishing more effective care for all patients.

The efficacy of botulinum toxin A treatment for tension-type or cervicogenic headache: a systematic review and meta-analysis of randomized, placebo-controlled trials

OBJECTIVES

The pathogeneses of chronic tension-type headache (CTTH) and cervicogenic headache (CEH) are not well established. Peripheral activation or sensitization of myofascial nociceptors is suggested as a potential mechanism and injections of botulinum toxin (BONTA) have thus been used in the treatment for both headache conditions. BONTA inhibits the release of acetylcholine at the neuromuscular junction and inhibits contraction of skeletal muscles. If the pain is precipitated by increased tone in cervical muscles, local injections of BONTA could represent a prophylactic measure. However, the treatment is still controversial, and a thorough assessment of the current evidence is required. This review aims to assess the evidence of BONTA injection as a prophylactic treatment for CTTH and CEH by reviewing and examining the quality of placebo-controlled, randomized trials.

METHODS

Data sources: we searched in the following databases: PubMed (including Medline), Embase, Cochrane Central register of Controlled Trials, Cinahl, Amed, SCOPUS and Google Scholar including other repository sources. Both MeSH and free keywords were used in conducting the systematic search in the databases. The search covered publications from the root of the databases to November 2020.

STUDY ELIGIBILITY CRITERIA

The review included RCTs, comparing single treatment of BONTA with placebo on patients with CTTH or CEH above 18 years of age, by measuring pain severity/relief or headache frequency.

DATA EXTRACTION

The following data were extracted: year of publication, country, setting, trial design, number of participants, injection procedure, BONTA dosages, and clinical outcome measures.

STUDY APPRAISAL

To assess validity and quality, and risk of bias, the Oxford Pain Validity Scale, Modified Jadad Scale, last version of Cochrane Collaboration's tool for assessing risk of bias (RoB 2), and the CONSORT 2010 Checklist were used. The trials were assessed, and quality scored independently by two of the reviewers. A quantitative synthesis and meta-analyses of headache frequency and intensity were performed.

RESULTS

We extracted 16 trials, 12 on prophylactic BONTA treatment for CTTH and four on CEH. Of these 12 trials (8 on CTTH and 4 on CEH) were included in the quantitative synthesis. A majority of the trials found no significant difference on the primary outcome measure when BONTA treatment was compared with placebo. Three "positive" trials, reporting significant difference in favor of BONTA treatment, but two of these were hampered by low validity and quality scores and high risk of bias.

CONCLUSIONS

There is no clear clinical evidence supporting prophylactic treatment with BONTA for CTTH or CEH.

Response of the autonomic activity to stress provocation in females with cervicogenic headache compared to asymptomatic controls: a cross-sectional study

BACKGROUND

Because abnormal activity of the autonomic nervous system is associated with chronification of pain, early detection of such dysfunction is important.

AIM

Although several studies highlight autonomic dysfunction in the chronification of headache, no study discussed its role in episodic cervicogenic headache.

DESIGN

Case-controlled cross-sectional single-blind comparative study between women with episodic cervicogenic headache and matched controls.

SETTING

Outpatient setting, Hasselt University.

POPULATION

Autonomic activity of 17 females with episodic cervicogenic headache (26.6±11.6 years) was compared with 17 age, gender and socio-economic matched asymptomatic controls (26.8±11.9 years).

METHODS

Autonomic activity was compared via repeated measures of the activity of the dermal sweat glands (µmho), peripheral circulation (%), electrical activity of the bilateral upper trapezius (μV) before, during and after cognitive stress provocation.

RESULTS

Whereas the autonomic parameters of the control group behaved as expected, participants in the headache group showed: 1) to stress provocation a significant lower dermal sweat gland activity (3.03±0.44 vs. 4.19±0.91 µmho, P<0.0001), higher vasodilatation (-5.56±1.45% vs. -5.61±1.85%, P=0.03), lower activity of the left upper trapezius (0.21±0.44 vs. 0.89±0.59 µV, P=0.03), significant less recuperation of the dermal sweat gland activity (-2.57±0.40 vs. -3.29±0.84 µmho, P<0.0001); 2) no recuperation of the activity (μV) of the left (P=0.83) and right (P=0.99) upper trapezius; 3) from stress provocation to recuperation a significant negative correlation (ρ=0.69, P=0.04) between dermal sweat gland and right upper trapezius activity.

CONCLUSIONS

Females with episodic cervicogenic headache reacted less to cognitive stress provocation. Recuperation after such provocation was absent. More research is needed to associate autonomous responses with a possible chronification process.

CLINICAL REHABILITATION IMPACT

A dysfunctional reaction to cognitive stress could be a threat to allostasis.

Phenotypic Characterization of Paclitaxel-Induced Peripheral Neuropathy in Cancer Survivors

CONTEXT

Although paclitaxel is one of the most commonly used drugs to treat breast, ovarian, and lung cancers, little is known about the impact of paclitaxel-induced peripheral neuropathy (PIPN) on cancer survivors.

OBJECTIVES

The purposes of this study were to evaluate for differences in demographic and clinical characteristics as well as measures of sensation, balance, upper extremity function, perceived stress, symptom burden, and quality of life (QOL) between survivors who received paclitaxel and did (n = 153) and did not (n = 58) develop PIPN.

METHODS

Pain characteristics associated with PIPN are described in detail. Both subjective and objective measures were used to evaluate the impact of PIPN.

RESULTS

Survivors with PIPN were significantly older, had a higher body mass index, and a worse comorbidity profile. The duration of PIPN was almost four years, and pain scores were in the moderate range. Compared with survivors without PIPN, survivors with PIPN had a higher number of upper and lower extremity sites that had lost light touch, cold, and pain sensations. Survivors with PIPN had worse upper extremity function, more problems with balance, a higher symptom burden, and higher levels of perceived stress. In addition, survivors with PIPN had worse QOL scores particularly in the domain of physical functioning.

CONCLUSION

The findings from this large descriptive study are the first to document the impact of PIPN on survivors' symptom burden, functional status, and QOL.

Associations Between Perceived Stress and Chemotherapy-Induced Peripheral Neuropathy and Otoxicity in Adult Cancer Survivors

CONTEXT

The most common adverse effects from neurotoxic chemotherapy are chemotherapy-induced neuropathy (CIPN), hearing loss, and tinnitus. Although associations between perceived stress and persistent pain, hearing loss, and tinnitus are documented, no studies have examined these associations in cancer survivors who received neurotoxic chemotherapy.

OBJECTIVES

In this cross-sectional study, we evaluated for associations between perceived stress and the occurrence of CIPN, hearing loss, and tinnitus, in 623 adult cancer survivors who received platinum and/or taxane compounds.

METHODS

Survivors completed self-report measures of hearing loss, tinnitus, and perceived stress (i.e., Impact of Events Scale-Revised [IES-R]). Separate logistic regression analyses were done for each neurotoxicity to evaluate whether each of the IES-R subscale (i.e., intrusion, avoidance, hyperarousal) and total scores made a significant independent contribution to neurotoxicity group membership.

RESULTS

Of the 623 survivors in this study, 68.4% had CIPN, 34.5% reported hearing loss, and 31.0% reported tinnitus. Older age, higher body mass index, poorer functional status, being born prematurely, cancer diagnosis, and higher intrusion (P = 0.013), hyperarousal (P = 0.014), and total (P = 0.047) IES-R scores were associated with CIPN. Older age, being male, poorer functional status, a worse comorbidity profile, and a higher IES-R hyperarousal (P = 0.007) score were associated with hearing loss. Being male, having less education, a worse comorbidity profile, and a higher IES-R hyperarousal (P = 0.029) score were associated with tinnitus.

CONCLUSION

These findings suggest that increased levels of perceived stress are associated with the most common chemotherapy-induced neurotoxicities.

Systematic review of quantitative imaging biomarkers for neck and shoulder musculoskeletal disorders

Background

This study systematically summarizes quantitative imaging biomarker research in non-traumatic neck and shoulder musculoskeletal disorders (MSDs). There were two research questions: 1) Are there quantitative imaging biomarkers associated with the presence of neck and shoulder MSDs?, 2) Are there quantitative imaging biomarkers associated with the severity of neck and shoulder MSDs?

Methods

PubMed and SCOPUS were used for the literature search. One hundred and twenty-five studies met primary inclusion criteria. Data were extracted from 49 sufficient quality studies.

Results

Most of the 125 studies were cross-sectional and utilized convenience samples of patients as both cases and controls. Only half controlled for potential confounders via exclusion or in the analysis. Approximately one-third reported response rates. In sufficient quality articles, 82% demonstrated at least one statistically significant association between the MSD(s) and biomarker(s) studied. The literature synthesis suggested that neck muscle size may be decreased in neck pain, and trapezius myalgia and neck/shoulder pain may be associated with reduced vascularity in the trapezius and reduced trapezius oxygen saturation at rest and in response to upper extremity tasks. Reduced vascularity in the supraspinatus tendon may also be a feature in rotator cuff tears. Five of eight studies showed an association between a quantitative imaging marker and MSD severity.

Conclusions

Although research on quantitative imaging biomarkers is still in a nascent stage, some MSD biomarkers were identified. There are limitations in the articles examined, including possible selection bias and inattention to potentially confounding factors. Recommendations for future studies are provided.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1694-y) contains supplementary material, which is available to authorized users.

Accelerated aging in adults with knee osteoarthritis pain: consideration for frequency, intensity, time, and total pain sites

INTRODUCTION

Individuals with osteoarthritis (OA) show increased morbidity and mortality. Telomere length, a measure of cellular aging, predicts increased morbidity and mortality. Telomeres shorten with persisting biological and psychosocial stress. Living with chronic OA pain is stressful. Previous research exploring telomere length in people with OA has produced inconsistent results. Considering pain severity may clarify the relationship between OA and telomeres.

OBJECTIVES

We hypothesized that individuals with high OA chronic pain severity would have shorter telomeres than those with no or low chronic pain severity.

METHODS

One hundred thirty-six adults, ages 45 to 85 years old, with and without symptomatic knee OA were included in the analysis. Peripheral blood leukocyte telomere length was measured, and demographic, clinical, and functional data were collected. Participants were categorized into 5 pain severity groups based on an additive index of frequency, intensity, time or duration, and total number of pain sites (FITT). Covariates included age, sex, race or ethnicity, study site, and knee pain status.

RESULTS

The no or low chronic pain severity group had significantly longer telomeres compared with the high pain severity group, P = 0.025. A significant chronic pain severity dose response emerged for telomere length, P = 0.034. The FITT chronic pain severity index was highly correlated with the clinical and functional OA pain measures. However, individual clinical and functional measures were not associated with telomere length.

CONCLUSION

Results demonstrate accelerated cellular aging with high knee OA chronic pain severity and provide evidence for the potential utility of the FITT chronic pain severity index in capturing the biological burden of chronic pain.

Allostatic load and pain severity in older adults: Results from the English Longitudinal Study of Ageing

Pain is common in older adults, is frequently experienced as stressful, and is associated with increased morbidity and mortality. Stress regulatory systems are adaptive to challenge and change, allostasis, until demands exceed the adaptive capacity contributing to dysregulation, resulting in a high allostatic load. A high allostatic load is associated with increased risk of morbidity and mortality. Pain severity, based on the average intensity of frequent pain, was hypothesized to be positively associated with AL. Four formulations of AL were investigated. Cross-sectional data from Wave 4 (2008-2009) of the English Longitudinal Study of Aging (ELSA) were analyzed. Covariates in the model included age, sex, education, smoking status, alcohol consumption, activity level, depression and common comorbid health conditions. A total of 5341 individuals were included; mean age 65.3(±9.2) years, 55% female, 62.4% infrequent or no pain, 12.6% mild pain, 19.1% moderate pain, and 5.9% severe pain. Severe pain was associated with greater AL defined by all four formulations. The amount of variance explained by pain severity and the covariates was highest when allostatic load was defined by the high risk quartile (12.9%) and by the clinical value (11.7%). Findings indicate a positive relationship between pain severity and AL. Further investigation is needed to determine if there is a specific AL signature for pain that differs from other health conditions.

Sensory and sympathetic disorders in chronic non-specific neck pain

The signs of sympathetic and sensory nerve-related disorders are not widely investigated in chronic nonspecific neck pain (NNP) patients. Thus, we performed skin temperature (Tsk), evaporation and touch threshold (TT) measurements to reveal possible dysfunctions at the fingertips of NNP patients (n=60) compared with healthy controls (n=11). Neck pain intensity was the main modifier of Tsk, and age the main modifier of TT in a multivariate model. On comparisons of the subgroups of NNP patients with unilateral (n=26) and bilateral (n=34) symptoms and controls, TT differed and Tsk tended to differ, the unilateral pain patients being found to demonstrate higher TT values on both sides. Interrelations between the measured parameters were found in the controls, but not in the patients. The NNP patients exhibited signs of functional impairment of innervation reflected in changes in tactile sensitivity and vasoactive sympathetic function. These changes may be based on both central and peripheral mechanisms, which possibly differ in patients with unilateral and bilateral symptoms.

Investigating the Burden of Chronic Pain: An Inflammatory and Metabolic Composite

Background. Chronic pain is associated with increased morbidity and mortality, predominated by cardiovascular disease and cancer. Investigating related risk factor measures may elucidate the biological burden of chronic pain. Objectives. We hypothesized that chronic pain severity would be positively associated with the risk factor composite. Methods. Data from 12,982 participants in the 6th Tromsø study were analyzed. Questionnaires included demographics, health behaviors, medical comorbidities, and chronic pain symptoms. The risk factor composite was comprised of body mass index, fibrinogen, C-reactive protein, and triglycerides. Chronic pain severity was characterized by frequency, intensity, time/duration, and total number of pain sites. Results. Individuals with chronic pain had a greater risk factor composite than individuals without chronic pain controlling for covariates and after excluding inflammation-related health conditions (p < 0.001). A significant "dose-response" relationship was demonstrated with pain severity (p < 0.001). In individuals with chronic pain, the risk factor composite varied by health behavior, exercise, lower levels and smoking, and higher levels. Discussion. The risk factor composite was higher in individuals with chronic pain, greater with increasing pain severity, and influenced by health behaviors. Conclusions. Identification of a biological composite sensitive to pain severity and adaptive/maladaptive behaviors would have significant clinical and research utility.

Stress-induced allodynia--evidence of increased pain sensitivity in healthy humans and patients with chronic pain after experimentally induced psychosocial stress

Background

Experimental stress has been shown to have analgesic as well as allodynic effect in animals. Despite the obvious negative influence of stress in clinical pain conditions, stress-induced alteration of pain sensitivity has not been tested in humans so far. Therefore, we tested changes of pain sensitivity using an experimental stressor in ten female healthy subjects and 13 female patients with fibromyalgia.

Methods

Multiple sensory aspects of pain were evaluated in all participants with the help of the quantitative sensory testing protocol before (60 min) and after (10 and 90 min) inducing psychological stress with a standardized psychosocial stress test (“Trier Social Stress Test”).

Results

Both healthy subjects and patients with fibromyalgia showed stress-induced enhancement of pain sensitivity in response to thermal stimuli. However, only patients showed increased sensitivity in response to pressure pain.

Conclusions

Our results provide evidence for stress-induced allodynia/hyperalgesia in humans for the first time and suggest differential underlying mechanisms determining response to stressors in healthy subjects and patients suffering from chronic pain. Possible mechanisms of the interplay of stress and mediating factors (e.g. cytokines, cortisol) on pain sensitivity are mentioned. Future studies should help understand better how stress impacts on chronic pain conditions.

Salivary cortisol and melatonin levels in children with frequent episodic tension-type headache do not differ from healthy children

AIM

To investigate the differences in cortisol and melatonin concentrations between children with frequent episodic tension-type headache (FETTH) and healthy children.

METHODS

Forty-four children, 12 boys/32 girls (age: 9 ± 2 years) with FETTH associated to peri-cranial tenderness and 44 age- and sex- matched healthy children participated. Both salivary cortisol and melatonin concentrations were collected from non-stimulated saliva following standardized guidelines. A headache diary for 4 weeks was used for collecting intensity, frequency and duration of headache.

RESULTS

No significant differences for cortisol (t = -0.431; p = 0.668), and melatonin (z = -1.564; p = 0.118) concentrations and salivary flow rate (z = -1.190; p = 0.234) were found between both groups. No significant effect of age or gender was found. In addition, no significant association between cortisol-melatonin concentrations and between cortisol-melatonin concentrations and headache clinical parameters were found.

CONCLUSION

These results suggest that children with FETTH, at first instance, do not present deficits in the secretion of these cortisol and melatonin. Prospective longitudinal studies are needed to further elucidate the direction of current findings, particularly the synchronism of cortisol and melatonin and the course of the headache.

Chronic migraine plus medication overuse headache: two entities or not?

Chronic migraine (CM) represents migraine natural evolution from its episodic form. It is realized through a chronicization phase that may require months or years and varies from patient to patient. The transition to more frequent attacks pattern is influenced by lifestyle, life events, comorbid conditions and personal genetic terrain, and it often leads to acute drugs overuse. Medication overuse headache (MOH) may complicate every type of headache and all the drugs employed for headache treatment can cause MOH. The first step in the management of CM complicated by medication overuse must be the withdrawal of the overused drugs and a detoxification treatment. The goal is not only to detoxify the patient and stop the chronic headache but also to improve responsiveness to acute or prophylactic drugs. Different methods have been suggested: gradual or abrupt withdrawal; home treatment, hospitalization, or a day-hospital setting; re-prophylaxes performed immediately or at the end of the wash-out period. Up to now, only topiramate and local injection of onabotulinumtoxinA have shown efficacy as therapeutic agents for re-prophylaxis after detoxification in patients with CM with and without medication overuse. Although the two treatments showed similar efficacy, onabotulinumtoxinA is associated with a better adverse events profile. Recently, the Phase III Research Evaluating Migraine Prophylaxis Therapy (PREEMPT) clinical program proved that patients with CM, even those with MOH, are the ones most likely to benefit from onabotulinumtoxinA treatment. Furthermore, it provided an injection paradigm that can be used as a guide for a correct administration of onabotulinumtoxinA.

Effects of heart rate variability biofeedback in subjects with stress-related chronic neck pain: a pilot study

Recent studies focusing on autonomic nervous system (ANS) dysfunctions, together with theoretical pathophysiological models of musculoskeletal disorders, indicate the involvement of ANS regulation in development and maintenance of chronic muscle pain. Research has demonstrated the effectiveness of heart rate variability (HRV) biofeedback (BF) in increasing HRV and reducing the symptoms of different disorders characterized by ANS aberration. The study investigated the effects of resonance frequency HRV BF on autonomic regulation and perceived health, pain, stress and disability in 24 subjects with stress-related chronic neck-shoulder pain. Twelve subjects participated in 10 weekly sessions of resonant HRV BF and were compared to a control group. Subjective reports and HRV measures during relaxation and in response to a standardized stress protocol were assessed for both groups pre- and post-intervention. Group × time interactions revealed a significantly stronger increase over time in perceived health (SF-36) for the treatment group, including vitality, bodily pain and social functioning. Interactions were also seen for HRV during relaxation and reactivity to stress. The present pilot study indicates improvement in perceived health over a 10 week intervention with HRV-biofeedback in subjects with chronic neck-pain. Increased resting HRV as well as enhanced reactivity to hand grip and cold pressor tests might reflect beneficial effects on ANS regulation, and suggest that this intervention protocol is suitable for a larger controlled trial.

Effects of static contraction and cold stimulation on cardiovascular autonomic indices, trapezius blood flow and muscle activity in chronic neck-shoulder pain

The aim of the present study was to investigate reactions in trapezius muscle blood flow (MBF), muscle activity, heart rate variability (HRV) and systemic blood pressure (BP) to autonomic tests in subjects with chronic neck-shoulder pain and healthy controls. Changes in muscle activity and blood flow due to stress and unfavourable muscle loads are known underlying factors of work-related muscle pain. Aberration of the autonomic nervous system (ANS) is considered a possible mechanism. In the present study, participants (n = 23 Pain, n = 22 Control) performed autonomic tests which included a resting condition, static hand grip test (HGT) at 30% of maximal voluntary contraction, a cold pressor test (CPT) and a deep breathing test (DBT). HRV was analysed in time and frequency domains. MBF and muscle activity were recorded from the upper trapezius muscles using photoplethysmography and electromyography (EMG). The pain group showed reduced low frequency-HRV (LF) and SDNN during rest, as well as a blunted BP response and increased LF-HRV during HGT (∆systolic 22 mm Hg; ∆LF(nu) 27%) compared with controls (∆systolic 27; ∆LF(nu) 6%). Locally, the pain group had attenuated trapezius MBF in response to HGT (Pain 122% Control 140%) with elevated trapezius EMG following HGT and during CPT. In conclusion, only HGT showed differences between groups in systemic BP and HRV and alterations in local trapezius MBF and EMG in the pain group. Findings support the hypothesis of ANS involvement at systemic and local levels in chronic neck-shoulder pain.

Lower immunglobulin A levels but not lower cortisol or α-amylase activity in children with chronic tension-type headache

Objective

The tudy was designed to investigate the differences in salivary cortisol (hypothalamic-pituitary-adrenocortical[HPA] axis), immunoglobulin A (IgA) (immune system) concentrations and α-amylase (sympathetic nervous system [SNS]) activity between children with chronic tension-type headache (CTTH) and healthy children.

Methods

Thirty-six children, 10 boys and 26 girls (age: 9±2 years) with CTTH and 36 age - and sex-matched healthy children were recruited. Salivary cortisol, αm-amylase activity, salivary flow rate, IgA concentration and IgA rate were collected from non-stimulated saliva. A headache diary was used for collecting data on intensity, frequency and duration of headache for four weeks.

Results

Children with CTTH showed lower IgA concentration (p = .008) and IgA rate (p = .039), but not lower cortisol concentration (p = .447), salivary flow rate (p = .289) or α-amylase activity (p = .559), as compared to healthy children. Neither age (p < .582) nor gender (p < .227) influenced salivary markers. A significant association between the number of years with headache and IgA concentration (rs = - 0.385; p = .023) was found: the greater the number of years with headache, the lower the IgA concentration.

Conclusions

These results suggest that children with CTTH present with deficits in the immune system, but not dysfunction in the HPA axis or SNS. Future studies are needed to elucidate the direction of these relationships.

What is the effect of selective serotonin reuptake inhibitors on temperament and character in patients with fibromyalgia?

OBJECTIVE

The purpose of the present study was to assess a group of patients with fibromyalgia (FM) and control subjects using the personality questionnaire proposed by Cloninger and to determine possible changes in the Italian version of the Temperament and Character Inventory-Revised patterns of patients with FM after therapy with serotoninergic antidepressants (selective serotonin reuptake inhibitors [SSRIs]).

METHODS

Sixty patients with FM filled out the Temperament and Character Inventory-Revised and Beck Depression Inventory before and after 6-month therapy with SSRIs (escitalopram 10 mg, fluoxetine 20 mg, or paroxetine 20 mg). A total of 80 age-, sex-, and education level-matched healthy subjects were selected as a control group.

RESULTS

Both in the pretreatment and posttreatment period, patients were found to have higher harm avoidance and lower self-directedness scores than healthy controls. In addition, harm avoidance and self-directedness were state and trait dependent.

CONCLUSIONS

Depressive symptoms in patients with FM can be significantly decreased by treatment with SSRIs. A careful clinical assessment and study of personality profile is needed to identify patients with FM who may benefit from antidepressant pharmacologic therapy and specific psychotherapeutic interventions.

A possible neural basis for stress-induced hyperalgesia

Intense stress and fear have long been known to give rise to a suppression of pain termed "stress-induced analgesia", mediated by brainstem pain-modulating circuitry, including pain-inhibiting neurons of the rostral ventromedial medulla. However, stress does not invariably suppress pain, and indeed, may exacerbate it. Although there is a growing support for the idea of "stress-induced hyperalgesia", the neurobiological basis for this effect remains almost entirely unknown. Using simultaneous single-cell recording and functional analysis, we show here that stimulation of the dorsomedial nucleus of the hypothalamus, known to be a critical component of central mechanisms mediating neuroendocrine, cardiovascular and thermogenic responses to mild or "emotional" stressors such as air puff, also triggers thermal hyperalgesia by recruiting pain-facilitating neurons, "ON-cells", in the rostral ventromedial medulla. Activity of identified RVM ON-cells, OFF-cells and NEUTRAL cells, nociceptive withdrawal thresholds, rectal temperature, and heart rate were recorded in lightly anesthetized rats. In addition to the expected increases in body temperature and heart rate, disinhibition of the DMH induced a robust activation of ON-cells, suppression of OFF-cell firing and behavioral hyperalgesia. Blocking ON-cell activation prevented hyperalgesia, but did not interfere with DMH-induced thermogenesis or tachycardia, pointing to differentiation of neural substrates for autonomic and nociceptive modulation within the RVM. These data demonstrate a top-down activation of brainstem pain-facilitating neurons, and suggest a possible neural circuit for stress-induced hyperalgesia.

Mental turmoil, suicide risk, illness perception, and temperament, and their impact on quality of life in chronic daily headache

To evaluate the relationship among quality of life, temperament, illness perception, and mental turmoil in patients affected by chronic daily headache with concomitant medication overuse headache. Participants were 116 consecutive adult outpatients admitted to the Department of General Medicine of the Sant'Andrea Hospital in Rome, between January 2007 and December 2007 with a diagnosis of chronic daily headache (illness duration >5 years). Patients were administered the Temperament Evaluation of Memphis, Pisa, Paris and San Diego-autoquestionnaire version (TEMPS-A), the Beck Hopelessness Scale (BHS), the Hamilton Rating Scale for Depression (HAM-D), the Mini-International Neuropsychiatric Interview (MINI), the Revised Illness Perception Questionnaire (IPQ), the Suicide Score Scale (SSS), and the Quality of Life Index (QL-Index). Twenty-eight percent of the patients evidenced moderate to severe depression, and 35% evidenced severe hopelessness. Analyses also indicated that quality of life, temperament, illness perception, and psychological turmoil are associated. However, a hierarchical multivariate regression analysis with quality of life as dependent variable indicated that only a model with mental turmoil variables may fit data; further, only the MINI suicidal intent resulted associated with quality of life (standardized regression coefficient = -0.55; t = -3.06; P < 0.01). Suicide risk may play a central role in affecting the quality of life of patients with chronic headache. The investigation of the interplay of factors that precipitate suicide risk should include assessment of chronic headache and its effects on wellbeing.