Neural Plasticity in Common Forms of Chronic Headaches. Neural Plast. 2015;2015:205985. [PMID: 26366304 PMCID: PMC4558449 DOI: 10.1155/2015/205985]

Dopamine D2 Receptor Activation Blocks GluA2/ROS Positive Feedback Loop to Alienate Chronic-Migraine-Associated Pain Sensitization

Chronic migraine is a disabling disorder without effective therapeutic medicine. AMPA receptors have been proven to be essential to pathological pain and headaches, but the related regulatory mechanisms in chronic migraine have not yet been explored. In this study, we found that the level of surface GluA2 was reduced in chronic migraine rats. Tat-GluR23Y (a GluA2 endocytosis inhibitor) reduced calcium inward flow and weakened synaptic structures, thus alleviating migraine-like pain sensitization. In addition, the inhibition of GluA2 endocytosis reduced the calcium influx and alleviated mitochondrial calcium overload and ROS generation in primary neurons. Furthermore, our results showed that ROS can induce allodynia and GluA2 endocytosis in rats, thus promoting migraine-like pain sensitization. In our previous study, the dopamine D2 receptor was identified as a potential target in the treatment of chronic migraine, and here we found that dopamine D2 receptor activation suppressed chronic-migraine-related pain sensitization through blocking the GluA2/ROS positive feedback loop in vivo and in vitro. Additionally, ligustrazine, a core component of ligusticum chuanxiong, was shown to target the dopamine D2 receptor, thereby alleviating ROS production and abnormal nociception in CM rats. This study provides valuable insight into the treatment of chronic migraine.

Adverse Childhood Experiences and Primary Headache Disorders: A Systematic Review, Meta-analysis, and Application of a Biological Theory

BACKGROUND AND OBJECTIVES

Headache disorders are among the leading causes of disability worldwide. While an association between adverse childhood experiences and primary headaches has been reported, the pooled magnitude across studies and pathways of the association are unknown. Our objectives were (1) to estimate the pooled effect of ≥1 adverse childhood experience (ACE) on primary headache disorders in adulthood and (2) to test the hypothesis that ACEs categorized as "threat" traumas or "deprivation" traumas have distinct effects on primary headaches based on a selected theory from our narrative review of how ACEs affect human development along the life course.

METHODS

PubMed, EMBASE, MEDLINE, Web of Science, Google Scholar, Biological Psychiatry, and gray literature were searched up to March 16, 2023 (PROSPERO, CRD42020223403). Selected articles included (1) observational studies with a comparator group, (2) ACEs that occurred before 18 years of age, and (3) primary headaches occurring at or after 21 years of age. Pooled odds ratios (ORs) were calculated using multilevel linear random-effects modeling. The narrative review included theories that describe how ACEs affect human development and disease across the life course. We selected a theory from our narrative review and tested ACEs categorized according to this theory for any modification of point estimates.

RESULTS

Our search identified 32 studies, of which 28 were eligible for meta-analysis (n = 154,739 participants, 19 countries). The occurrence of ≥1 adverse childhood experience(s) was associated with primary headaches (pooled OR = 1.48 [95% CI 1.36-1.61]; high-quality evidence, 134,696 participants). As the number of ACEs increased, the odds of primary headaches increased (range: 1 ACE OR = 1.24 [95% CI 1.14-1.35] to ≥4 ACEs OR = 2.09 [95% CI 1.83-2.38], p for trend <0.0001). From the narrative review, a neurodevelopmental theory that categorizes ACEs into threat or deprivation was tested, and both were independently associated with primary headaches (threat OR = 1.46 [95% CI 1.32-1.60] and deprivation OR = 1.35 [95% CI 1.23-1.49], respectively), accounting for heterogeneity (p = 0.021).

DISCUSSION

This systematic review and meta-analysis confirm that ACEs are important risk factors of primary headache disorders in adulthood. Our findings provide epidemiologic support that ACEs categorized as threat and deprivation may manifest as distinct pathways of early adversity.

Migraine: interactions between brain's trait and state

It is well established that migraine is a multifactorial disorder. A deep understanding of migraine should be based upon both the underlying traits and the current states affected by different physiological, psychological, and environmental factors. At this point, there is no framework fully meeting these criteria. Here, we describe a broader view of the migraine disorder defined as a dysfunctional brain state and trait interaction. In this model, we consider events that may enhance or diminish migraine responsivity based on an individual's trait and state. This could provide an expanded view for considering how migraine attacks are sometimes precipitated by "triggers" and sometimes not, how these factors only lead to migraine attacks in migraine patients, or how individuals with an increased risk for migraine do not show any symptoms at all. Summarizing recent studies and evidence that support the concept of migraine as a brain state-trait interaction can also contribute to improving patient care by highlighting the importance of precision medicine and applying measures that are able to capture how different traits and states work together to determine migraine.

Manual therapy in adults with tension-type headache: A systematic review

INTRODUCTION

Tension-type headache is the most common primary headache, with a high prevalence and a considerable socioeconomic impact. Manual physical therapy techniques are widely used in the clinical field to treat the symptoms associated with tension-type headache. This systematic review aims to determine the effectiveness of manual and non-invasive therapies in the treatment of patients with tension-type headache.

DEVELOPMENT

We conducted a systematic review of randomised controlled trials in the following databases: Brain, PubMed, Web of Science, PEDro, Scopus, CINAHL, and Science Direct. Ten randomised controlled trials were included for analysis. According to these studies, manual therapy improves symptoms, increasing patients' well-being and improving the outcome measures analysed.

CONCLUSIONS

Manual therapy has positive effects on pain intensity, pain frequency, disability, overall impact, quality of life, and craniocervical range of motion in adults with tension-type headache. None of the techniques was found to be superior to the others; combining different techniques seems to be the most effective approach.

Clinical and Neurophysiological Effects of Botulinum Neurotoxin Type A in Chronic Migraine

Chronic pain syndromes present a subversion of both functional and structural nociceptive networks. We used transcranial magnetic stimulation (TMS) to evaluate changes in cortical excitability and plasticity in patients with chronic migraine (CM) treated with botulinum neurotoxin type A (BoNT/A). We enrolled 11 patients with episodic migraine (EM) and 11 affected by CM. Baseline characteristics for both groups were recorded using single- and paired-pulse TMS protocols. The same TMS protocol was repeated in CM patients after four cycles of BoNT/A completed in one year. At baseline, compared with EM patients, patients with CM had a lower threshold in both hemispheres (right hemisphere: 46% ± 7.8 vs. 52% ± 4.28, p = 0.03; left hemisphere: 52% ± 4.28 vs. 53.54% ± 6.58, p = 0.02). In EM, paired-pulse stimulation elicited a physiologically shaped response, whereas in CM, physiological intracortical inhibition (ICI) between 1 and 3 ms intervals was absent at baseline. On the contrary, increasing intracortical facilitation (ICF) was observed for all interstimulus intervals (ISIs). In CM, cortical excitability was partially reduced after BoNT/A treatment, along with a significant decrease observed in MIDAS score (from 20.7 to 9.8; p = 0.008). The lower motor threshold in CM reflects a higher cortical hyperexcitability. The lack of physiological ICI in CM could indicate sensitisation of the trigeminovascular system. Although reduced, this type of response is still observable after treatment, despite a marked clinical improvement. Our study suggests a long-term alteration of cortical plasticity due to chronic pain.

[Cognitive and emotional disorders in patients with migraine and signs of leukoencephalopathy]

OBJECTIVE

To identify cognitive and emotional disorders and their correlation with neuroimaging parameters in patients with chronic migraine.

MATERIAL AND METHODS

We examined 50 patients (8 men and 42 women, mean age 41.9±11.9 years) with migraine, including 31 with chronic migraine, and signs of leukoencephalopathy according to magnetic resonance imaging (MRI). A control group comprised 40 healthy individuals (13 men and 27 women) aged 20 to 64 years (mean 42.6±12.0 years). A number of tests for neuropsychological examination and assessment of the emotional state, including a 12-word test, literal and categorical associations, Benton Test, the Montreal cognitive scale (MOCA), the Hospital Depression Scale, the Beck Depression Scale, the Center for Epidemiological Research scale, the Hospital Anxiety Scale and the Spielberger-Khanin scale, were administered at baseline and after 3 and 6 month of preventive therapy.

RESULTS

Patients with migraine had lower scores (p=0.004) on MOCA, memorization of 12 words (p=0.0003), test for literal (p=0.001) and categorical associations (p=0.0002) compared with the control group. No significant correlations were found between the volume of white matter lesions according to MRI and the severity of cognitive impairment. An inverse correlation of average strength was noted (correlation coefficient R=-0.41) between the number of days with headache per month and the MOCA score (p<0.05). In patients with migraine, signs of depression were found on the Hospital Depression Scale (p=0.04), Beck Depression Scale (p=0.003), the Center for Epidemiological Research scale (p=0.0001), and increased anxiety on the Hospital Anxiety Scale (p=0.0001) and the Spielberger-Khanin scale (p=0.0001). A significant relationship was found between the degree of depression and the MOCA score (p=0.007). The frequency of headaches decreased from 19.4±2.9 to 12.6±4.4 days per month (p<0.05).

CONCLUSION

There were a significant decrease of emotional disorders and improvement of cognitive functions compared with baseline scores during the 6 month therapy. Preventive treatment of migraine and concomitant emotional disorders seems to be the most effective way to improve cognitive functions.

Contributions of aversive environmental stress to migraine chronification: Research update of migraine pathophysiology

Clinical studies have suggested that internal and/or external aversive cues may produce a negative affective-motivational component whereby maladaptive responses (plasticity) of dural afferent neurons are initiated contributing to migraine chronification. However, pathophysiological processes and neural circuitry involved in aversion (unpleasantness)-producing migraine chronification are still evolving. An interdisciplinary team conducted this narrative review aimed at reviewing neuronal plasticity for developing migraine chronicity and its relevant neurocircuits and providing the most cutting-edge information on neuronal mechanisms involved in the processing of affective aspects of pain and the role of unpleasantness evoked by internal and/or external cues in facilitating the chronification process of migraine headache. Thus, information presented in this review promotes the understanding of the pathophysiology of chronic migraine and contribution of unpleasantness (aversion) to migraine chronification. We hope that it will bring clinicians’ attention to how the maladaptive neuroplasticity of the emotion brain in the aversive environment produces a significant impact on the chronification of migraine headache, which will in turn lead to new therapeutic strategies for this type of pain.

Proton Magnetic Resonance Spectroscopy to Detect Correlations between Clinical Symptoms and Brain Metabolite Levels in Patients with Tension-type Headache

Background:

Proton magnetic resonance spectroscopy (¹HMRS) is a noninvasive method to quantify pain. A ¹HMRS spectrum is a group of peaks at different radiofrequencies, showing proton nuclei in various chemical environments. These MR spectra provide information about metabolite concentrations, and make MRS a useful procedure to monitor metabolic fluctuations due to disease, and to track the efficacy of treatment.

Objective:

This study aims to identify correlations between clinical symptoms in patients with tension-type headache (TTH) and concentrations of brain metabolites.

Material and Methods:

In this observational study, twenty-four patients (4 men and 20 women) with chronic TTH were included. To evaluate their clinical symptoms, the number of trigger points, headache frequency and headache intensity were recorded. The levels of anxiety and depression were recorded with the Beck Anxiety Inventory (BAI) and Beck Depression Inventory II (BDI- II). Concentrations of brain metabolites were determined in the anterior cingulate cortex, thalamus and primary somatosensory cortex of left hemisphere with ¹HMRS.

Results:

There was a negative correlation between trigger point count and choline/creatine (Cho/Cr) ratio in the primary somatosensory cortex [r= −0.509, n= 24, p= 0.01]. There were no correlations between other clinical symptoms of TTH and concentrations of brain metabolites.

Conclusion:

Patients with more trigger points had a lower Cho/Cr ratio, which may indicate alterations in brain metabolic activity.

Intracortical Inhibition in the Affected Hemisphere in Limb Amputation

Phantom limb pain (PLP) affects up to 80% of amputees. Despite the lack of consensus about the etiology and pathophysiology of phantom experiences, previous evidence pointed out the role of changes in motor cortex excitability as an important factor associated with amputation and PLP. In this systematic review, we investigated changes in intracortical inhibition as indexed by transcranial magnetic stimulation (TMS) in amputees and its relationship to pain. Four electronic databases were screened to identify studies using TMS to measure cortical inhibition, such as short intracortical inhibition (SICI), long intracortical inhibition (LICI) and cortical silent period (CSP). Seven articles were included and evaluated cortical excitability comparing the affected hemisphere with the non-affected hemisphere or with healthy controls. None of them correlated cortical disinhibition and clinical parameters, such as the presence or intensity of PLP. However, most studies showed decreased SICI in amputees affected hemisphere. These results highlight that although SICI seems to be changed in the affected hemisphere in amputees, most of the studies did not investigate its clinical correlation. Thus, the question of whether they are a valid diagnostic marker remains unanswered. Also, the results were highly variable for both measurements due to the heterogeneity of study designs and group comparisons in each study. Although these results underscore the role of inhibitory networks after amputation, more studies are needed to investigate the role of a decreased inhibitory drive in the motor cortex to the cause and maintenance of PLP.

Retinal Nerve Fiber Layer Thickness and Oxidative Stress Parameters in Migraine Patients without Aura: A Pilot Study

BACKGROUND

Migraine is one of the most common disorders and its pathophysiological mechanisms are still under research, oxidative stress being emphasized as an important contributor. This study aimed to analyze the retinal nerve fiber layer (RNFL) thickness and oxidative/anti-oxidant balance in migraine patients.

METHODS

Two groups of subjects were evaluated: a group of patients with migraine and a control group of healthy volunteers. RNFL thickness was assessed for all subjects by the ocular coherence tomography spectral domain (OCT-SD). The oxidative stress parameter, namely nitric oxide (NOx), malondialdehyde (MDA), and total oxidative stress (TOS) were assessed. The antioxidant capacity of plasma was evaluated by assessing the level of catalase, and total anti-oxidative (TOS) capacity. Migraine severity was graded using the Migraine Disability Assessment Score (MIDAS) questionnaire.

RESULTS

All the oxidative stress parameters (NOx, MDA, and TOS) were significantly increased, and both parameters for anti-oxidative status were significantly decreased in the migraine group compared with the control group (p < 0.0001). Significant correlations with all the quadrants and different oxidative stress parameters were found, most involved being temporal quadrant. A significant positive correlation between catalase and macular RNFL thickness (inner ring, temporal quadrant) in migraine patients, for both eyes, was observed (p = 0.014 for the right eye and p = 0.12 for the left eye).

CONCLUSION

The assessment of the oxidative stress/anti-oxidative balance together with RFLN thickness can constitute a promising method to evaluate the progression of the diseases. It can also contribute to the estimation of the efficiency of various therapies targeting oxidative stress and associated inflammation.

The fifth cranial nerve in headaches

The fifth cranial nerve is the common denominator for many headaches and facial pain pathologies currently known. Projecting from the trigeminal ganglion, in a bipolar manner, it connects to the brainstem and supplies various parts of the head and face with sensory innervation. In this review, we describe the neuroanatomical structures and pathways implicated in the sensation of the trigeminal system. Furthermore, we present the current understanding of several primary headaches, painful neuropathies and their pharmacological treatments. We hope that this overview can elucidate the complex field of headache pathologies, and their link to the trigeminal nerve, to a broader field of young scientists.

Genetic Screening of Plasticity Regulating Nogo-Type Signaling Genes in Migraine

Migraine is the sixth most prevalent disease in the world and a substantial number of experiments have been conducted to analyze potential differences between the migraine brain and the healthy brain. Results from these investigations point to the possibility that development and aggravation of migraine may include grey matter plasticity. Nogo-type signaling is a potent plasticity regulating system in the CNS and consists of ligands, receptors, co-receptors and modulators with a dynamic age- and activity-related expression in cortical and subcortical regions. Here we investigated a potential link between migraine and five key Nogo-type signaling genes: RTN4, OMGP, MAG, RTN4R and LINGO1, by screening 15 single nucleotide polymorphisms (SNPs) within these genes. In a large Swedish migraine cohort (749 migraine patients and 4032 controls), using a logistic regression with sex as covariate, we found that there was no such association. In addition, a haplotype analysis was performed which revealed three haplotype blocks. These blocks had no significant association with migraine. However, to robustly conclude that Nogo-type genotypes signaling do not influence the prevalence of migraine, further studies are encouraged.

Osteopathic Manipulative Therapy in Patients With Chronic Tension-Type Headache: A Pilot Study

CONTEXT

Nonpharmacologic treatment, such as osteopathic manipulative therapy (OMTh; manipulative care provided by foreign-trained osteopaths) may be a beneficial complementary treatment for tension-type headache. However, to the authors' knowledge, the benefit of OMTh in the management of tension-type headache has not been explored, especially chronic tension-type headache (CTTH).

OBJECTIVE

To investigate the effectiveness of OMTh compared with traditional treatment in reducing pain intensity, frequency, and duration of CTTH, and to evaluate the objective postural measurement of the forward head posture (FHP) as an integral parameter in the assessment of the effects of OMTh and traditional management of CTTH.

METHODS

Patients with CTTH were registered at the Headache Centre of Trieste in Italy. At the time of the study, none of the patients had been taking any headache prophylaxis in the past 3 months. A 3-month baseline period was recorded by all patients with an ad hoc diary. Patients were randomly placed in the test or control group using a simple randomization program in Excel (Microsoft). Patients in the OMTh group underwent a 3-month period of OMTh, and patients in the control group were treated with amitriptyline. Pain intensity, frequency, and duration of headaches, as well as FHP were analyzed.

RESULTS

The study enrolled 10 patients (mean [SD] age, 42.6 [15.2] years) in the OMTh group and 10 patients (51.4 [17.3] years) in the control group. The final assessment of OMTh patients showed statistically significant changes in all headache parameters: pain intensity decreased from a mean (SD) score of 4.9 (1.4) to 3.1 (1.1) (P=.002); frequency decreased from 19.8 (6) to 8.3 (6.2) days per month (P=.002); and the duration of headaches decreased from 10 (4.2) to 6 (3) hours (P=.01). Significant improvement of all parameters was found in the control group as well: pain intensity decreased from a mean (SD) score of 5.9 (0.7) to 4.2 (1.75) (P=.03); frequency decreased from 23.4 (7.2) to 7.4 (8.7) days per month (P=.003); and duration decreased from 7.8 (2.9) to 3.6 (2.1) hours (P=.002). Forward head posture significantly improved in OMTh patients (P=.003).

CONCLUSIONS

Our data suggested that OMTh may be an effective treatment to improve headaches in patients with CTTH. Our results also suggest that OMTh may reduce FHP.

Perivascular neurotransmitters: Regulation of cerebral blood flow and role in primary headaches

In order to understand the nature of the relationship between cerebral blood flow (CBF) and primary headaches, we have conducted a literature review with particular emphasis on the role of perivascular neurotransmitters. Primary headaches are in general considered complex polygenic disorders (genetic and environmental influence) with pathophysiological neurovascular alterations. Identified candidate headache genes are associated with neuro- and gliogenesis, vascular development and diseases, and regulation of vascular tone. These findings support a role for the vasculature in primary headache disorders. Moreover, neuronal hyperexcitability and other abnormalities have been observed in primary headaches and related to changes in hemodynamic factors. In particular, this relates to migraine aura and spreading depression. During headache attacks, ganglia such as trigeminal and sphenopalatine (located outside the blood-brain barrier) are variably activated and sensitized which gives rise to vasoactive neurotransmitter release. Sympathetic, parasympathetic and sensory nerves to the cerebral vasculature are activated. During migraine attacks, altered CBF has been observed in brain regions such as the somatosensory cortex, brainstem and thalamus. In regulation of CBF, the individual roles of neurotransmitters are partly known, but much needs to be unraveled with respect to headache disorders.

Depression is not the only cause of cognitive impairment in chronic migraine

Background. Patients with the chronic migraine frequently present with memory and attention complaints. However, the prevalence and phenotype of such impairment in chronic migraine have not been studied.

Objective – to evaluate the prevalence of the objective cognitive deficit in patients with chronic migraine and factors underlying its etiology.

 Materials and methods. We recruited 62 subjects with chronic migraine and 36 genderand age-matched controls with low-frequency episodic migraine (not more, then 4 headache days per month) aged 18–59. All patients filled in the Hospital Anxiety and Depression Scale (HADS) and Sheehan Disability Scale. Cognitive function was assessed with the Montreal Cognitive Assessment (MoCA), Digital Symbol Substitution Test (DSST), Rey Auditory Verbal Learning Test (RAVLT), and the Perceived Deficits Questionnaire (PDQ-20).

Results. In this study 58 % of patients with chronic migraine complained of memory loss. Cognitive impairment was also found with PDQ-20. Objectively, we found a significant decrease in 90-second DSST results and RAVLT total recall and learning rate. In 40 % of subjects with chronic migraine scored lower than 26 points on MoCA. Patients with chronic migraine more frequently had lower DSST rates as compared to episodic migraine (odds ratio 5.07 (95 % confidence interval – 1.59–16.17); p = 0.003). Depression and anxiety did not correlate with performance on cognitive tests. Chronic migraine (frequent headache) and longer headache history, but not depression, anxiety or medication overuse were independent predictors of cognitive impairment.

Conclusion. Subjective and objective cognitive deficits are prevalent in the chronic migraine population. Most often memory and attention are impaired. Longer headache history and presence of chronic migraine are independent risk factors for cognitive impairment in patients with chronic migraine.

Neurophysiological correlates of clinical improvement after greater occipital nerve (GON) block in chronic migraine: relevance for chronic migraine pathophysiology

BACKGROUND

Therapeutic management of Chronic Migraine (CM), often associated with Medication Overuse Headache (MOH), is chiefly empirical, as no biomarker predicting or correlating with clinical efficacy is available to address therapeutic choices. The present study searched for neurophysiological correlates of Greater Occipital Nerve Block (GON-B) effects in CM.

METHODS

We recruited 17 CM women, of whom 12 with MOH, and 19 healthy volunteers (HV). Patients had no preventive treatment since at least 3 months. After a 30-day baseline, they received a bilateral betamethasone-lidocaine GON-B of which the therapeutic effect was assessed 1 month later. Habituation of visual evoked potentials (VEP) and intensity dependence of auditory evoked potentials (IDAP) were recorded before and 1 week after the GON-B.

RESULTS

At baseline, CM patients had a VEP habituation not different from HV, but a steeper IDAP value than HV (p = 0.01), suggestive of a lower serotonergic tone. GON-B significantly reduced the number of total headache days per month (- 34.9%; p = 0.003). Eight out 17CM patients reversed to episodic migraine and medication overuse resolved in 11 out of 12 patients. One week after the GON-B VEP habituation became lacking respect to baseline (p = 0.01) and to that of HV (p = 0.02) like in episodic migraine, while the IDAP slope significantly flattened (p < 0.0001). GON-B-induced reduction in headache days positively correlated with IDAP slope decrease (rho = 0.51, p = 0.03).

CONCLUSIONS

GON-B may be effective in the treatment of CM, with or without MOH. The pre-treatment IDAP increase is compatible with a weak central serotonergic tone, which is strengthened after GON-B, suggesting that serotonergic mechanisms may play a role in CM and its reversion to episodic migraine. Since the degree of post-treatment IDAP decrease is correlated with clinical improvement, IDAP might be potentially useful as an early predictor of GON-B efficacy.

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.

Pericranial Tenderness in Females With Episodic Cervical Headache vs Asymptomatic Controls: A Cross-sectional Study

OBJECTIVES

The purpose of this study was to compare pericranial tenderness of females with episodic cervical headache vs matched asymptomatic controls.

METHODS

Through a single-blind, cross-sectional study, pericranial tenderness was compared between 20 females with episodic cervical headaches (29.4 ± 13.2 years) and 20 age-matched female asymptomatic controls (30.1 ± 13.7 years). Pericranial tenderness was bilaterally measured in a headache-free period with the "total tenderness score" (TTS) in the suboccipital, temporal, frontal, masseter, upper trapezius (UT), levator scapula, and sternocleidomastoid (SCM) muscle insertions. Passive cervical mobility, headache intensity, frequency, and duration were secondary outcomes. Analysis was done with a 95% confidence level (SPSS version 22). The Mann-Whitney U-test was used to compare pericranial, cephalic, cervical, and muscle-specific tenderness between groups. Correlations between passive cervical mobility and headache characteristics and the TTS were estimated with Spearman's ρ.

RESULTS

The headache group (1.25 ± 0.89) showed a 2 times higher (P < .05) pericranial TTS compared to the control group (0.62 ± 0.70). Higher (P < .05) scores were observed for the left suboccipital, temporal, masseter, UT, levator scapula, and SCM muscles and the right suboccipital, frontal, UT, and levator scapula muscles. Grouping the tenderness scores into cervical (suboccipital, UT, levator scapula, SCM) and cephalic (frontal, temporal, masseter) regions revealed greater scores (P < .05) in the headache group. In the latter, the TTS was significantly positively correlated with passive cervical extension (ρ = 0.78).

CONCLUSION

Consistent higher tenderness scores were observed and suggest involvement of sensitization in patients with episodic cervical headaches. A positive correlation was seen between passive cervical extension and sensitivity.

Pain chronification: what should a non-pain medicine specialist know?

OBJECTIVE

Pain is one of the most common reasons for an individual to consult their primary care physician, with most chronic pain being treated in the primary care setting. However, many primary care physicians/non-pain medicine specialists lack enough awareness, education and skills to manage pain patients appropriately, and there is currently no clear, common consensus/formal definition of "pain chronification".

METHODS

This article, based on an international Change Pain Chronic Advisory Board meeting which was held in Wiesbaden, Germany, in October 2016, provides primary care physicians/non-pain medicine specialists with a narrative overview of pain chronification, including underlying physiological and psychosocial processes, predictive factors for pain chronification, a brief summary of preventive strategies, and the role of primary care physicians and non-pain medicine specialists in the holistic management of pain chronification.

RESULTS

Based on currently available evidence, we propose the following consensus-based definition of pain chronification which provides a common framework to raise awareness among non-pain medicine specialists: "Pain chronification describes the process of transient pain progressing into persistent pain; pain processing changes as a result of an imbalance between pain amplification and pain inhibition; genetic, environmental and biopsychosocial factors determine the risk, the degree, and time-course of chronification."

CONCLUSIONS

Early intervention plays an important role in preventing pain chronification and, as key influencers in the management of patients with acute pain, it is critical that primary care physicians are equipped with the necessary awareness, education and skills to manage pain patients appropriately.

Functional Neuroimaging Biomarkers in Migraine: Diagnostic, Prognostic and Therapeutic Implications

BACKGROUND

In current migraine clinical practice, conventional neuroimaging examinations are often sought to exclude possible causes of secondary headaches or migraineassociated disorders. Contrariwise, although advanced Magnetic Resonance Imaging (MRI) has improved tremendously our understanding of human brain processes in migraine patients, to the state of the art they have not superseded the conventional neuroimaging techniques in the migraine clinical setting.

METHODS

A comprehensive review was conducted of PubMed citations by entering the keyword "marker" and/or "biomarker" combined with "migraine" and/or "headache". Other keywords included "imaging" or "neuroimaging", "structural" or "functional". The only restriction was English-language publication. The abstracts of all articles meeting these criteria were reviewed, and the full text was retrieved and examined for relevant references.

RESULTS

Several authors tried to identify imaging biomarkers able to identify different migraine phenotypes or, even better, to follow-up the same migraine patients during the course of the disease, to predict the evolution into more severe phenotypes and, finally, the response to specific treatment.

CONCLUSION

The identification of diagnostic, prognostic and therapeutic advanced neuroimaging biomarkers in the migraine clinical setting, in order to approach to patients in a more and more rational and "tailored" way, is extremely intriguing and futuristic. Unfortunately, reliable and robust neuroimaging biomarkers are still lacking for migraine, probably due to both not completely understood pathogenesis and clinical and neuroimaging heterogeneity. Although further longitudinal advanced neuroimaging studies, aimed to identify effective neuroimaging biomarkers, are needed, this review aims to collect the main and most recent works on this topic.

Longitudinal assessment of gray matter volumes and white matter integrity in patients with medication-overuse headache

Background Medication-overuse headache is a common clinical entity, but neuroimaging studies investigating volumetric and microstructural alterations of the brain in medication-overuse headache are rare. Therefore, in the current longitidunal study we evaluated gray matter volume and white matter integrity in patients with medication-overuse headache before and after drug withdrawal. Methods A prospective study evaluated 27 patients with medication-overuse headache and 27 age-, sex-, and education-matched healthy adults. High-resolution T1-weighted magnetic resonance imaging and diffusion tensor imaging were obtained from the control group and medication-overuse headache patients before and six months after drug withdrawal. Tract-based spatial statistics of multiple diffusivity indices and voxel-based morphometry were employed to investigate white and gray matter abnormalities. Results No correlation was found between age, gender, education and smoking status in both groups. The most commonly overused medications were simple analgesics (96.3%) and combined analgesics (3.7%). The mean duration of the history of medication overuse and headaches was 56.7 ± 63.5 months. White matter diffusional and gray matter morphological alterations including volume, fractional anisotropy, radial diffusivity, and axial diffusivity analyses showed no significant relationship in the patients before and six months after withdrawal of analgesics. Also no difference was observed between the patients versus controls. Conclusion Our data demonstrated no structural alterations within the brain in medication-overuse headache.

Comparison of gray matter volume between migraine and "strict-criteria" tension-type headache

BACKGROUND

Despite evidently distinct symptoms, tension-type headache (TTH) and migraine are highly comorbid and exhibit many similarities in clinical practice. The purpose of this study was to investigate whether both types of headaches are similar in brain morphology.

METHODS

Consecutive patients with TTH and age- and sex-matched patients with migraine and healthy controls were enrolled for brain magnetic resonance imaging examination. Patients with TTH were excluded if they reported any headache features or associated symptoms of migraine. Changes in gray matter (GM) volume associated with headache diagnosis (TTH vs. migraine) and frequency (episodic vs. chronic) were examined using voxel-based morphometry. The correlation with headache profile and the discriminative ability between TTH and migraine were also investigated for these GM changes.

RESULTS

In comparison with controls (n = 43), the patients with TTH (25 episodic and 24 chronic) exhibited a GM volume increase in the anterior cingulate cortex, supramarginal gyrus, temporal pole, lateral occipital cortex, and caudate. The patients with migraine (31 episodic and 25 chronic) conversely exhibited a GM volume decrease in the orbitofrontal cortex. These GM changes did not correlate with any headache profile. A voxel-wise 2 × 2 factorial analysis further revealed the substantial effects of headache types and frequency in the comparison of GM volume between TTH and migraine. Specifically, the migraine group (vs. TTH) had a GM decrease in the superior and middle frontal gyri, cerebellum, dorsal striatum, and precuneus. The chronic group (vs. episodic group) otherwise demonstrated a GM decrease in the bilateral insula and anterior cingulate cortex. In receiver operating characteristic analysis, the GM volumes of the left superior frontal gyrus and right cerebellum V combined had good discriminative ability for distinguishing TTH and migraine (area under the curve = 0.806).

CONCLUSIONS

TTH and migraine are separate headache disorders with different characteristics in relation to GM changes. The major morphological difference between the two types of headaches is the relative GM decrease of the prefrontal and cerebellar regions in migraine, which may reflect a higher allostatic load associated with this disabling headache.

Anodal transcranial direct current stimulation over the left temporal pole restores normal visual evoked potential habituation in interictal migraineurs

Background

Neuroimaging data has implicated the temporal pole (TP) in migraine pathophysiology; the density and functional activity of the TP were reported to fluctuate in accordance with the migraine cycle. Yet, the exact link between TP morpho-functional abnormalities and migraine is unknown. Here, we examined whether non-invasive anodal transcranial direct current stimulation (tDCS) ameliorates abnormal interictal multimodal sensory processing in patients with migraine.

Methods

We examined the habituation of visual evoked potentials and median nerve somatosensory evoked potentials (SSEP) before and immediately after 20-min anodal tDCS (2 mA) or sham stimulation delivered over the left TP in interictal migraineurs.

Results

Prior to tDCS, interictal migraineurs did not exhibit habituation in response to repetitive visual or somatosensory stimulation. After anodal tDCS but not sham stimulation, migraineurs exhibited normal habituation responses to visual stimulation; however, tDCS had no effect on SSEP habituation in migraineurs.

Conclusion

Our study shows for the first time that enhancing excitability of the TP with anodal tDCS normalizes abnormal interictal visual information processing in migraineurs. This finding has implications for the role of the TP in migraine, and specifically highlights the ventral stream of the visual pathway as a pathophysiological neural substrate for abnormal visual processing in migraine.

Cortical plasticity between the pain and pain-free phases in patients with episodic tension-type headache

Background

State-related brain structural alterations in patients with episodic tension-type headache (ETTH) are unclear. We aimed to conduct a longitudinal study to explore dynamic gray matter (GM) changes between the pain and pain-free phases in ETTH.

Methods

We recruited 40 treatment-naïve ETTH patients and 40 healthy controls. All participants underwent brain structural scans on a 3.0-T MRI system. ETTH patients were scanned in and out of pain phases. Voxel-based morphometry analysis was used to determine the differences in regional gray matter density (GMD) between groups. Additional regression analysis was used to identify any associations between regional GMD and clinical symptoms.

Results

ETTH patients exhibited reduced GMD in the bilateral primary somatosensory cortex, and increased GMD in the bilateral anterior cingulate cortex (ACC) and anterior insula for the in pain phase compared with the out of pain phase. The out of pain phase of ETTH patients exhibited no regions with higher or lower GMD compared with healthy controls. GMD in the left ACC and left anterior insula was negatively correlated with headache days. GMD in the left ACC was negatively correlated with anxiety and depressive symptoms in ETTH patients.

Conclusions

This is the first study to demonstrate dynamic and reversible GMD changes between the pain and pain-free phases in ETTH patients. However, this balance might be disrupted by increased headache days and progressive anxiety and depressive symptoms.

A 'complex' of brain metabolites distinguish altered chemistry in the cingulate cortex of episodic migraine patients

Despite the prevalence of migraine, the pathophysiology of the disease remains unclear. Current understanding of migraine has alluded to the possibility of a hyperexcitable brain. The aim of the current study is to investigate human brain metabolite differences in the anterior cingulate cortex (ACC) during the interictal phase in migraine patients. We hypothesized that there may be differences in levels of excitatory neurotransmitters and/or their derivatives in the migraine cohort in support of the theory of hyperexcitability in migraine. 2D J-resolved proton magnetic resonance spectroscopy (¹H-MRS) data were acquired on a 3 Tesla (3 T) MRI from a voxel placed over the ACC of 32 migraine patients (MP; 23 females, 9 males, age 33 ± 9.6 years) and 33 healthy controls (HC; 25 females, 8 males, age 32 ± 9.6 years). Amplitude correlation matrices were constructed for each subject to evaluate metabolite discriminability. ProFit-estimated metabolite peak areas were normalized to a water reference signal to assess subject differences. The initial analysis of variance (ANOVA) was performed to test for group differences for all metabolites/creatine (Cre) ratios between healthy controls and migraineurs but showed no statistically significant differences. In addition, we used a multivariate approach to distinguish migraineurs from healthy subjects based on the metabolite/Cre ratio. A quadratic discriminant analysis (QDA) model was used to identify 3 metabolite ratios sufficient to minimize minimum classification error (MCE). The 3 selected metabolite ratios were aspartate (Asp)/Cre, N-acetyl aspartate (NAA)/Cre, and glutamine (Gln)/Cre. These findings are in support of a ‘complex’ of metabolite alterations, which may underlie changes in neuronal chemistry in the migraine brain. Furthermore, the parallel changes in the three-metabolite ‘complex’ may confer more subtle but biological processes that are ongoing. The data also support the current theory that the migraine brain is hyperexcitable even in the interictal state.

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3 T MRI was used to acquire 2D J-resolved proton magnetic resonance spectroscopy.

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Metabolite alterations are reported in the anterior cingulate cortex of episodic migraineurs.

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The complex of metabolites may reflect multiple chemical changes in migraineurs.

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The observed chemical changes support the theory that the brain of migraineurs is hyperexcitable.

New Directions in the Treatment of Chronic Pain: National Pain Strategy Will Guide Prevention, Management, and Research

More than four years after the release of a landmark report by the Institute of Medicine focused attention on pain in America, there are encouraging signs that the nation may be poised to undergo the "cultural transformation" advocated by the report.

Update of Inpatient Treatment for Refractory Chronic Daily Headache

Chronic daily headache (CDH) is a group of headache disorders, in which headaches occur daily or near-daily (>15 days per month) and last for more than 3 months. Important CDH subtypes include chronic migraine, chronic tension-type headache, hemicrania continua, and new daily persistent headache. Other headaches with shorter durations (<4 h/day) are usually not included in CDH. Common comorbidities of CDH are medication overuse headache and various psychiatric disorders, such as depression and anxiety. Indications of inpatient treatment for CDH patients include poor responses to outpatient management, need for detoxification for overuse of specific medications (particularly opioids and barbiturates), and severe psychiatric comorbidities. Inpatient treatment usually involves stopping acute pain, preventing future attacks, and detoxifying medication overuse if present. Multidisciplinary integrated care that includes medical staff from different disciplines (e.g., psychiatry, clinical psychology, and physical therapy) has been recommended. The outcomes of inpatient treatment are satisfactory in terms of decreasing headache intensity or frequency, withdrawal from medication overuse, reducing disability, and improving life quality, although long-term relapse is not uncommon. In conclusion, inpatient treatment may be useful for select patients with refractory CDH and should be incorporated in a holistic headache care program.