Perceptions of pain in women with headache: a laboratory investigation of the influence of pain-related anxiety and fear

Quantifying sensory thresholds along the migraine cycle: An exploratory longitudinal study

BACKGROUND

To date, a number of studies on migraine have cross-sectionally evaluated sensory sensitivity with aversion thresholds/scores along the migraine cycle, reporting a decreased tolerance to sensory stimuli in different sensory modalities. Our hypothesis was that patients with migraine would exhibit heightened sensitivity to sound, light, touch and smell on days where they reported greater headache intensity.

METHODS

This is an exploratory, longitudinal study, carried out over the course of 27 days. Aversion thresholds or scores to sound, light, touch and smell were quantified in six patients with migraine (11.33 ± 6.53 headache days/month).

RESULTS

Patients reported an increased sensitivity to light (padj = 0.0297), touch (padj = 0.0077), and smell (padj = 0.0201) on days with higher headache intensity. However, a greater sensitivity to sound on days with higher headache intensity was only reported when anxiety levels were high (padj = 1.4e-06). Interestingly, variable levels of tolerance to bothersome light over time can also influence the correlation between light sensitivity and headache intensity (padj = 1.4e-06).

CONCLUSIONS

Based on the present findings, future longitudinal studies evaluating sensory threshold changes along the migraine cycle in patients with migraine should account for the increased tolerance to bothersome light over time as well as the effect of anxiety on auditory sensitivity.

Pain sensitivity in men who have never experienced a headache: an observer blinded case control study

Background

Headache affects 90–99% of the population. Based on the question “Do you think that you never ever in your whole life have had a headache?” 4% of the population say that they have never experienced a headache. The rarity of never having had a headache suggests that distinct biological and environmental factors may be at play. We hypothesized that people who have never experienced a headache had a lower general pain sensitivity than controls.

Methods

We included 99 male participants, 47 headache free participants and 52 controls, in an observer blinded nested case-control study. We investigated cold pain threshold and heat pain threshold using a standardized quantitative sensory testing protocol, pericranial tenderness with total tenderness score and pain tolerance with the cold pressor test. Differences between the two groups were assessed with the unpaired Student’s t-test or Mann-Whitney U test as appropriate.

Results

There was no difference in age, weight or mean arterial pressure between headache free participants and controls. We found no difference in pain detection threshold, pericranial tenderness or pain tolerance between headache free participants and controls.

Conclusion

Our study clearly shows that freedom from headache is not caused by a lower general pain sensitivity. The results support the hypothesis that headache is caused by specific mechanisms, which are present in the primary headache disorders, rather than by a decreased general sensitivity to painful stimuli.

Trial registration

Registered at ClinicalTrials.gov (NCT04217616), 3rd January 2020, retrospectively registered.

The role of self-evaluated pain sensitivity as a mediator of objectively measured pain tolerance in Native Americans: findings from the Oklahoma Study of Native American Pain Risk (OK-SNAP)

Native Americans (NAs) are at increased risk for chronic pain. One mechanism contributing to this pain disparity could be personal pain beliefs, which may influence actual pain sensitivity. Thus, we examined whether self-evaluated pain sensitivity (SEPS) mediates the relationship between ethnicity [NAs vs. non-Hispanic Whites (NHWs)] and objectively-measured pain tolerance, and whether catastrophic thinking and pain-related anxiety influence these pain beliefs. 232 healthy, pain-free NAs and NHWs completed questionnaires measuring SEPS, catastrophizing, and anxiety. Objective pain tolerance was also assessed. Results suggested: (1) NAs reported higher levels of SEPS, catastrophizing, and anxiety, (2) catastrophizing may have enhanced anxiety and both catastrophizing and anxiety were associated with higher SEPS, and (3) anxiety and SEPS were associated with lower pain tolerance. A significant bootstrapped mediation analysis suggested NAs experienced higher pain-related anxiety, which may have promoted higher SEPS, that in turn reduced pain tolerance. Longitudinal research is needed to confirm this.

Learning the full impact of migraine through patient voices: A qualitative study

OBJECTIVE

To better characterize the ways that migraine affects multiple domains of life.

BACKGROUND

Further understanding of migraine burden is needed.

METHODS

Adults with migraine randomized to mindfulness-based stress reduction or headache education arms (n = 81) in two separate randomized clinical trials participated in semistructured in-person qualitative interviews conducted after the interventions. Interviews queried participants on migraine impact on life and were audio-recorded, transcribed, and summarized into a framework matrix. A master codebook was created until meaning saturation was reached and magnitude coding established code frequency. Themes and subthemes were identified using a constructivist grounded theory approach.

RESULTS

Despite most participants being treated with acute and/or prophylactic medications, 90% (73/81) reported migraine had a negative impact on overall life, with 68% (55/81) endorsing specific domains of life impacted and 52% (42/81) describing impact on emotional health. Six main themes of migraine impact emerged: (1) global negative impact on overall life; (2) impact on emotional health; (3) impact on cognitive function; (4) impact on specific domains of life (work/career, family, social); (5) fear and avoidance (pain catastrophizing and anticipatory anxiety); and (6) internalized and externalized stigma. Participants reported how migraine (a) controls life, (b) makes life difficult, and (c) causes disability during attacks, with participants (d) experiencing a lack of control and/or (e) attempting to push through despite migraine. Emotional health was affected through (a) isolation, (b) anxiety, (c) frustration/anger, (d) guilt, (e) mood changes/irritability, and (f) depression/hopelessness. Cognitive function was affected through concentration and communication difficulties.

CONCLUSIONS

Migraine has a global negative impact on overall life, cognitive and emotional health, work, family, and social life. Migraine contributes to isolation, frustration, guilt, fear, avoidance behavior, and stigma. A greater understanding of the deep burden of this chronic neurological disease is needed to effectively target and treat what is most important to those living with migraine.

Walking the Tightrope: A Proposed Model of Chronic Pain and Stress

Pain and stress are both phenomena that challenge an individual’s homeostasis and have significant overlap in conceptual and physiological processes. Allostasis is the ability to adapt to pain and stress and maintain homeostasis; however, if either process becomes chronic, it may result in negative long-term outcomes. The negative effects of stress on health outcomes on physiology and behavior, including pain, have been well documented; however, the specific mechanisms of how stress and what quantity of stress contributes to the maintenance and exacerbation of pain have not been identified, and thus pharmacological interventions are lacking. The objective of this brief review is to: 1. identify the gaps in the literature on the impact of acute and chronic stress on chronic pain, 2. highlight future directions for stress and chronic pain research; and 3. introduce the Pain-Stress Model in the context of the current literature on stress and chronic pain. A better understanding of the connection between stress and chronic pain could provide greater insight into the neurobiology of these processes and contribute to individualized treatment for pain rehabilitation and drug development for these often comorbid conditions.

Pain Perception and Migraine

Background: It is well-known that both inter- and intra-individual differences exist in the perception of pain; this is especially true in migraine, an elusive pain disorder of the head. Although electrophysiology and neuroimaging techniques have greatly contributed to a better understanding of the mechanisms involved in migraine during recent decades, the exact characteristics of pain threshold and pain intensity perception remain to be determined, and continue to be a matter of debate.

Objective: The aim of this review is to provide a comprehensive overview of clinical, electrophysiological, and functional neuroimaging studies investigating changes during various phases of the so-called “migraine cycle” and in different migraine phenotypes, using pain threshold and pain intensity perception assessments.

Methods: A systematic search for qualitative studies was conducted using search terms “migraine,” “pain,” “headache,” “temporal summation,” “quantitative sensory testing,” and “threshold,” alone and in combination (subject headings and keywords). The literature search was updated using the additional keywords “pain intensity,” and “neuroimaging” to identify full-text papers written in English and published in peer-reviewed journals, using PubMed and Google Scholar databases. In addition, we manually searched the reference lists of all research articles and review articles.

Conclusion: Consistent data indicate that pain threshold is lower during the ictal phase than during the interictal phase of migraine or healthy controls in response to pressure, cold and heat stimuli. There is evidence for preictal sub-allodynia, whereas interictal results are conflicting due to either reduced or no observed difference in pain threshold. On the other hand, despite methodological limitations, converging observations support the concept that migraine attacks may be characterized by an increased pain intensity perception, which normalizes between episodes. Nevertheless, future studies are required to longitudinally evaluate a large group of patients before and after pharmacological and non-pharmacological interventions to investigate phases of the migraine cycle, clinical parameters of disease severity and chronic medication usage.

Experimental and procedural pain responses in primary dysmenorrhea: a systematic review

Primary dysmenorrhea (PD) has been the focus of a number of experimental pain studies. Although a number of reviews exist, few have critically evaluated the existing body of research on PD and experimental and procedural pain. Data from 19 published research articles that include women with PD and responses to an experimental or procedural pain stimulus (or stimuli) suggest that women with PD may have elevated pain reactivity, as compared to women without PD. This pattern appears to be true across different phases of the menstrual cycle. However, there is an abundance of conflicting findings, which may be due to significant methodological issues such as inconsistent definitions of PD, wide variation in experimental pain methodologies, and inaccurate assessment of the menstrual cycle. Future research should focus on identifying specific symptoms (i.e., pain threshold ratings) to more clearly define what constitutes PD, establish reliable and valid laboratory testing protocols, and assess the menstrual cycle with greater precision.

Does pain sensitivity change by migraine phase? A blinded longitudinal study

Objective

Studies suggest that pain thresholds may be altered before and during migraine headaches, but it is still debated if a central or peripheral dysfunction is responsible for the onset of pain in migraine. The present blinded longitudinal study explores alterations in thermal pain thresholds and suprathreshold heat pain scores before, during, and after headache.

Methods

We measured pain thresholds to cold and heat, and pain scores to 30 seconds of suprathreshold heat four times in 49 migraineurs and once in 31 controls. Sessions in migraineurs were categorized by migraine diaries as interictal, preictal (≤one day before attack), ictal or postictal (≤one day after attack).

Results

Trigeminal cold pain thresholds were decreased ( p = 0.014) and pain scores increased ( p = 0.031) in the ictal compared to the interictal phase. Initial pain scores were decreased ( p < 0.029), and the temporal profile showed less adaptation ( p < 0.020) in the preictal compared to the interictal phase. Hand cold pain thresholds were decreased in interictal migraineurs compared to controls ( p < 0.019).

Conclusion

Preictal heat hypoalgesia and reduced adaptation was followed by ictal trigeminal cold suballodynia and heat hyperalgesia. Our results support that cyclic alterations of pain perception occur late in the prodromal phase before headache. Further longitudinal investigation of how pain physiology changes within the migraine cycle is important to gain a more complete understanding of the pathogenic mechanisms behind the migraine attack.

The Effects of Inflammatory Tooth Pain on Anxiety in Adult Male Rats

Introduction:

This study aimed to examine the effects of induced inflammatory tooth pain on anxiety level in adult male rats.

Methods:

The mandibular incisors of 56 adult male rats were cut off and prefabricated crowns were fixed on the teeth. Formalin and capsaicin were injected intradentally to induce inflammatory tooth pain. Diazepam treated group received diazepam 30 minutes before intradental injection. The anxiety-related behavior was evaluated with elevated plus maze test.

Results:

Intradental application of chemical noxious stimuli, capsaicin and formalin, significantly affected nociceptive behaviors (P<0.001). Capsaicin (P<0.001) and formalin (P<0.01) significantly increased the anxiety levels in rats by decrease in the duration of time spent in open arm and increase in the duration of time spent in closed arm. Rats that received capsaicin made fewer open arm entries compared to the control animals (P<0.05). Capsaicin (P<0.001) and formalin (P<0.01) treated rats showed more stretch attend postures compared to the control and sham operated animals. In diazepampretreated rats, capsaicin induced algesic effect was prevented (P<0.001).

Conclusion:

Inflammatory pulpal pain has anxiogenic effect on rats, whereas diazepam premedication showed both anxiolytic and pain reducing effects.

Reliable Digit Span is Unaffected by Laboratory-Induced Pain

Reliable Digit Span (RDS) is an indicator used to assess the validity of cognitive test performance. Scores of 7 or lower suggest poor effort or negative response bias. The possibility that RDS scores are also affected by pain has not been addressed thus potentially threatening RDS specificity. The current study used cold pressor-induced pain to investigate the effect of pain on RDS scores. Sixty undergraduate volunteers randomly assigned to one of three conditions (control, simulator, pain) completed the Digit Span subtest from the Wechsler Adult Intelligence Scale-III from which the RDS is derived. No differences in RDS scores were found between the control and pain groups, and neither group scored below 8. Sixty-five percent of the simulator group scored 7 or below. These results suggest that RDS is not affected by pain, and scores of 7 or less in persons with pain can be more confidently attributed to negative response bias.

Who is healthy? Aspects to consider when including healthy volunteers in QST--based studies-a consensus statement by the EUROPAIN and NEUROPAIN consortia

Clinical and human experimental pain studies often include so-called "healthy" controls in investigations of sensory abnormalities, using quantitative sensory testing (QST) as an outcome measure. However, the criteria for what is considered "healthy" vary among the different studies and between study centers and investigators, partly explaining the high variability of the results. Therefore, several aspects should be considered during inclusion of healthy volunteers in QST-based trials to have homogenous groups of healthy controls with less variability between human experimental studies, so that results are less likely to be false negative or false positive because of subject-related factors. The EUROPAIN and NEUROPAIN consortia aimed to define factors influencing the variability in selection of healthy subjects in QST-based studies before the start of both projects and to give recommendations how to minimize it based on the current literature and expertise of the participants. The present suggestions for inclusion criteria of healthy volunteers into QST-based trials describe a 2-level approach including standardized questionnaires enabling the collection of relevant information on sociodemographic data, medical history, current health status, coping strategies in dealing with pain, and the motivation of the volunteer to participate in the study. These suggestions are believed to help researchers interpret their results in comparison with others and improve the quality of clinical studies including healthy volunteers as controls or in human experimental pain studies. They aim to reduce any confounding factors. Furthermore, the acquired information will allow post hoc analyses of variance for different potential influencing factors.

Enhanced short-term sensitization of facial compared with limb heat pain

Habituation and sensitization are important features of individual sensitivity to repetitive noxious stimulation and have been investigated in numerous studies. However, it is unclear whether these phenomena vary depending on the site of stimulation. Here we compared short-term and long-term effects of painful heat stimulation on the forehead and limb using an established longitudinal heat pain paradigm performed over 8 consecutive days in 36 healthy volunteers. Participants were randomized into 2 groups; participants received repetitive heat pain stimulation either on the left volar forearm or on the left side of the forehead. Our data show a comparable degree of habituation over the course of 8 days in both groups. However, participants in the trigeminal stimulation group exhibited stronger within-session sensitization (indexed by a higher within-session increase in pain intensity ratings) than those who received the forearm stimulation. Furthermore, over the course of the experiment we found a correlation between habituation and anxiety, showing less habituation in participants with higher trait anxiety scores. Our findings are in line with somatotopic differences in response to painful stimulation and a higher proneness of trigeminal pain to sensitization processes, which might be explained by the biological relevance of the head and facial area for vital functions. The contribution of this sensitivity to the development and maintenance of clinical facial pain and headache disorders warrants further investigation.

PERSPECTIVE

This study uses psychophysical methods to evaluate the differences in long-term habituation and short-term sensitization to heat pain between the trigeminal and spinal systems. We found stronger sensitization for trigeminal compared with nociceptive stimuli on the forearm. The contribution of this sensitivity to clinical pain states warrants further investigation.

Habituation and sensitization in primary headaches

The phenomena of habituation and sensitization are considered most useful for studying the neuronal substrates of information processing in the CNS. Both were studied in primary headaches, that are functional disorders of the brain characterized by an abnormal responsivity to any kind of incoming innocuous or painful stimuli and it's cycling pattern over time (interictal, pre-ictal, ictal). The present review summarizes available data on stimulus responsivity in primary headaches obtained with clinical neurophysiology. In migraine, the majority of electrophysiological studies between attacks have shown that, for a number of different sensory modalities, the brain is characterised by a lack of habituation of evoked responses to repeated stimuli. This abnormal processing of the incoming information reaches its maximum a few days before the beginning of an attack, and normalizes during the attack, at a time when sensitization may also manifest itself. An abnormal rhythmic activity between thalamus and cortex, namely thalamocortical dysrhythmia, may be the pathophysiological mechanism subtending abnormal information processing in migraine. In tension-type headache (TTH), only few signs of deficient habituation were observed only in subgroups of patients. By contrast, using grand-average responses indirect evidence for sensitization has been found in chronic TTH with increased nociceptive specific reflexes and evoked potentials. Generalized increased sensitivity to pain (lower thresholds and increased pain rating) and a dysfunction in supraspinal descending pain control systems may contribute to the development and/or maintenance of central sensitization in chronic TTH. Cluster headache patients are characterized during the bout and on the headache side by a pronounced lack of habituation of the brainstem blink reflex and a general sensitization of pain processing. A better insight into the nature of these ictal/interictal electrophysiological dysfunctions in primary headaches paves the way for novel therapeutic targets and may allow a better understanding of the mode of action of available therapies.

Dysfunctional coping in headache: avoidance and endurance is not associated with chronic forms of headache

INTRODUCTION

About 4% of the population suffer from daily or near daily headache, which in most cases evolved from an episodic type of headache. The impact of psychological factors on this process is unknown. It seems reasonable to assume, that besides somatic and social conditions psychological factors like pain-related coping and cognition play an important role, as has been shown for other pain conditions.

METHODS

We performed a cross sectional study on pain coping behaviour in 211 patients with migraine and tension type headache. Pain-related cognition and coping was investigated using the Kiel Pain Inventory. Prevalence of depression, medication intake and headache characteristics were analysed in regard to chronicity of headache.

RESULTS

Overall pain intensity was high in the patient sample. The level of depression increased with headache frequency. Dysfunctional coping, characterized by fear and avoidance is frequently used by headache patients. As in low back pain, also endurance is highly prevalent. Other features known to be associated with chronic headache, like depression and medication overuse, could be confirmed.

DISCUSSION

Dysfunctional coping was seen with high prevalence in the entire patient sample (66%). Against our hypothesis, it was not confined to chronic forms of headache. In respect to our data, we discuss the role of avoidance and endurance coping in headache and its possible role in chronicity.

Pain sensitivity mediates the relationship between stress and headache intensity in chronic tension-type headache

BACKGROUND

A central model for chronic tension-type headache (CTH) posits that stress contributes to headache, in part, by aggravating existing hyperalgesia in CTH sufferers. The prediction from this model that pain sensitivity mediates the relationship between stress and headache activity has not yet been examined.

OBJECTIVE

To determine whether pain sensitivity mediates the relationship between stress and prospective headache activity in CTH sufferers.

METHOD

Self-reported stress, pain sensitivity and prospective headache activity were measured in 53 CTH sufferers recruited from the general population. Pain sensitivity was modelled as a mediator between stress and headache activity, and tested using a nonparametric bootstrap analysis.

RESULTS

Pain sensitivity significantly mediated the relationship between stress and headache intensity.

CONCLUSIONS

The results of the present study support the central model for CTH, which posits that stress contributes to headache, in part, by aggravating existing hyperalgesia in CTH sufferers. Implications for the mechanisms and treatment of CTH are discussed.

Stress and tension-type headache mechanisms

Stress is widely demonstrated as a contributing factor in tension-type headache (TTH). The mechanisms underlying this remain unclear at present. Recent research indicates the importance of central pain processes in tension-type headache (TTH) pathophysiology. Concurrently, research with animals and healthy humans has begun to elucidate the relationship between stress and pain processing in the central nervous system, including central pain processes putatively dysfunctional in TTH. Combined, these two fields of research present new insights and hypotheses into possible mechanisms by which stress may contribute to TTH. To date, however, there has been no comprehensive review of this literature. The present paper provides such a review, which may be valuable in facilitating a broader understanding of the central mechanisms by which stress may contribute to TTH.

An experimental investigation of emotional willingness and physical pain tolerance in deliberate self-harm: the moderating role of interpersonal distress

Although theoretical and clinical literature emphasize the role of both an unwillingness to experience emotional distress and physical pain tolerance in deliberate self-harm (DSH), research on their associations with DSH remains limited. This study sought to examine the relationships between DSH and the willingness to experience emotional distress and tolerate physical pain, including the moderating role of interpersonal distress in these relationships. To this end, young adults with recent DSH (n = 43) and controls without any DSH (n = 52) were randomly assigned to 1 of 2 emotion-induction conditions (distressing or neutral), after which behavioral measures of both the willingness to experience distress and physical pain tolerance were obtained. Consistent with hypotheses, findings indicated heightened physical pain tolerance among self-harming individuals only under conditions of interpersonal distress. Furthermore, findings provided some support for the hypothesized association between DSH and the unwillingness to experience emotional distress, suggesting that self-harming women evidence less willingness to experience emotional distress only under conditions of depleted regulatory capacity (eg, following an interpersonal stressor).

Migraine education improves quality of life in a primary care setting

OBJECTIVE

The objective of this study was to evaluate the effectiveness of the Mercy Migraine Management Program (MMMP), an educational program for physicians and patients. The primary outcome was change in headache days from baseline at 3, 6, and 12 months. Secondary outcomes were changes in migraine-related disability and quality of life, worry about headaches, self-efficacy for managing migraines, emergency room (ER) visits for headache, and satisfaction with headache care.

BACKGROUND

Despite progress in the understanding of the pathophysiology of migraine and development of effective therapeutic agents, many practitioners and patients continue to lack the knowledge and skills to effectively manage migraine. Educational efforts have been helpful in improving the quality of care and quality of life for migraine sufferers. However, little work has been performed to evaluate these changes over a longer period of time. Also, there is a paucity of published research evaluating the influence of education about migraine management on cognitive and emotional factors (for example, self-efficacy for managing headaches, worry about headaches).

METHODS

In this open-label, prospective study, 284 individuals with migraine (92% female, mean age = 41.6) participated in the MMMP, an educational and skills-based program. Of the 284 who participated in the program, 228 (80%) provided data about their headache frequency, headache-related disability (as measured by the Headache Impact Test-6 (HIT-6), migraine-specific quality of life (MSQ), worry about headaches, self-efficacy for managing headaches, ER visits for headaches, and satisfaction with care at 4 time points over 12 months (baseline, 3 months, 6 months, 12 months).

RESULTS

Overall, 46% (106) of subjects reported a 50% or greater reduction in headache frequency. Over 12 months, patients reported fewer headaches and improvement on the HIT-6 and MSQ (all P < .001). The improvement in headache impact and quality of life was greater among those who had more worry about their headaches at baseline. There were also significant improvements in "worry about headaches,""self-efficacy for managing headaches," and "satisfaction with headache care."

CONCLUSION

The findings demonstrate that patients participating in the MMMP reported improvements in their headache frequency as well as the cognitive and emotional aspects of headache management. This program was especially helpful among those with high amounts of worry about their headaches at the beginning of the program. The findings from this study are impetus for further research that will more clearly evaluate the effects of education and skill development on headache characteristics and the emotional and cognitive factors that influence headache.

Effect of mental stress on cold pain in chronic tension-type headache sufferers

Mental stress is a noted contributing factor in chronic tension-type headache (CTH), however the mechanisms underlying this are not clearly understood. One proposition is that stress aggravates already increased pain sensitivity in CTH sufferers. This hypothesis could be partially tested by examining effects of mental stress on threshold and supra-threshold experimental pain processing in CTH sufferers. Such studies have not been reported to date. The present study measured pain detection and tolerance thresholds and ratings of supra-threshold pain stimulation from cold pressor test in CTH sufferers (CTH-S) and healthy Control (CNT) subjects exposed to a 60-min stressful mental task, and in CTH sufferers exposed to a 60-min neutral condition (CTH-N). Headache sufferers had lower pain tolerance thresholds and increased pain intensity ratings compared to controls. Pain detection and tolerance thresholds decreased and pain intensity ratings increased during the stress task, with a greater reduction in pain detection threshold and increase in pain intensity ratings in the CTH-S compared to CNT group. The results support the hypothesis that mental stress contributes to CTH through aggravating already increased pain sensitivity in CTH sufferers.

Differences in trigeminal and peripheral electrical pain perception in women with and without migraine

Pain perception studies in migraine patients have shown trigeminal and peripheral pain facilitation during the migraine attack. We were interested in differences of trigeminal and peripheral pain perception between migraine patients during the migraine interval and healthy subjects. Perception of electrical pain stimulation was measured in 20 migraine subjects outside a migraine attack (10 migraine with aura and 10 migraine without aura) and in 20 healthy subjects. We recorded sensory and pain thresholds, pain ratings after suprathreshold stimulation, and pain rating after two trains of repetitive stimulation (i.e., pain facilitation). Migraine subjects showed a significantly higher pain rating after suprathreshold stimulation in the trigeminal region as compared to healthy subjects (4.8 ± 1.6 versus 3.8 ± 2.2, p < 0.04 after Bonferroni correction) but not in the peripheral region. Furthermore, migraine subjects showed a pain facilitation after repetitive trigeminal stimulation whereas healthy subjects showed a pain habituation. We observed no significant differences between migraine subjects and healthy subjects for all parameters in the peripheral stimulation. Migraine patients with and without aura did not differ in any parameter. All subjects showed decreased sensory and pain thresholds after trigeminal as compared to peripheral stimulation. Migraine subjects show an increased pain perception after trigeminal but not after peripheral pain stimulation as compared to healthy subjects. This phenomenon is probably due to the observed pain facilitation after painful trigeminal stimulation.

Cervical muscle co-activation in isometric contractions is enhanced in chronic tension-type headache patients

The purpose of the study was to compare the co-activation of cervical agonist and antagonist muscles between people with chronic tension-type headache (CTTH) and healthy controls during brief isometric cervical flexion and extension contractions. Nine women with CTTH and 10 matched controls participated. Surface electromyographic (EMG) signals were detected from the sternocleidomastoid and splenius capitis muscles bilaterally during cervical flexion and extension contractions of linearly increasing force from 0% to 60% of the maximum voluntary contraction (MVC) in 3 s. Sternocleidomastoid and splenius capitis EMG average rectified values (ARV) were estimated at 10% MVC force increments. During cervical extension contraction, sternocleidomastoid (i.e. antagonist muscle) ARV was greater for patients than for controls in the force range 20-60% MVC (P = 0.029). During cervical flexion, the left splenius capitis (i.e. antagonist muscle) ARV was greater for CTTH patients regardless of the force level (P = 0.02). Maximum cervical flexion and extension force was lower for the CTTH patients compared with controls (P = 0.001). In conclusion, women with CTTH demonstrated greater co-activation of antagonist musculature during cervical extension and flexion contractions compared with healthy women. Increased co-activation of antagonist musculature may reflect reorganization of the motor control strategy in CTTH patients, potentially leading to muscle overload and increased nociception.

Effects of the remote C fibres stimulation induced by capsaicin on the blink reflex in chronic migraine

The aim of this study was to test the function of the diffuse noxious inhibitory control system (DNIC) in chronic and episodic migraine, exploring the blink reflex (BR) modifications induced by topical application of capsaicin on the hand. We evaluated 11 migraine without aura (MA) and nine chronic migraine (CM) patients during the not symptomatic phase; they were compared with 14 non-headache subjects (N). The BR was elicited by weak electrical stimuli delivered to the right supraorbital nerve; it was obtained 10 min and 20 min after the application of 1 ml of 3% capsaicin in a cream base (Teofarma) on the skin of the dorsum of the right hand, and 60 min after capsaicin removal. The subjective pain sensation induced by capsaicin was significantly increased in CM with respect to both MA patients and normal subjects; the R2 area was increased in CM patients during capsaicin application, with respect to controls and MA patients, who did not exhibit any reflex alterations. These results may suggest a failure of DNIC and a disturbed control of the trigeminal reflex at the central level, linked with migraine frequency.

Psychological risk factors in headache

Headache is a chronic disease that occurs with varying frequency and results in varying levels of disability. To date, the majority of research and clinical focus has been on the role of biological factors in headache and headache-related disability. However, reliance on a purely biomedical model of headache does not account for all aspects of headache and associated disability. Using a biopsychosocial framework, the current manuscript expands the view of what factors influence headache by considering the role psychological (i.e., cognitive and affective) factors have in the development, course, and consequences of headache. The manuscript initially reviews evidence showing that neural circuits responsible for cognitive-affective phenomena are highly interconnected with the circuitry responsible for headache pain. The manuscript then reviews the influence cognitions (locus of control and self-efficacy) and negative affect (depression, anxiety, and anger) have on the development of headache attacks, perception of headache pain, adherence to prescribed treatment, headache treatment outcome, and headache-related disability. The manuscript concludes with a discussion of the clinical implications of considering psychological factors when treating headache.

The Fear of Pain questionnaire: factor structure in samples of young, middle-aged and elderly European people

The present study examined the factor structure of the Fear of Pain questionnaire in three independent samples composed of European young adults, middle-aged, and elderly people. Seven hundred and thirty one adults (426 females and 305 males) were presented with the French adaptation of the questionnaire (30 items) and with an Exposure to Painful Situations questionnaire that contained the same items as the Fear of Pain questionnaire and where participants were instructed to indicate all the painful situations they have experienced in the past. When tested on the whole set of 30 items, the correlated three-factor model evidenced in previous studies - Severe pain, Minor pain and Medical pain - poorly fit the data. When tested on a set of 15 two-item parcels, the fit of this model was much better but the correlations between factors were very high. When tested on a reduced set of 15 items, the model fit the data as well as when it was tested on the set of 15 parcels, and the correlations between the three factors were lower. The study also examined the link between previous exposure to pain and fear of pain. The hypothesis that previous "natural" exposure to pain should generally result in a decrease in fear of pain was supported by the data. For 14 items, the exposure effect was moderate to strong.