Noise as a Trigger for Headaches: Relationship Between Exposure and Sensitivity

Exploring the link between occupationally relevant whole body vibration and headache and neck pain: is elevated muscle tension an intermediary factor?

Whole body vibration (WBV) is linked to short- and longer-term adverse health outcomes, including cognitive impairment, stress and memory loss, loss of balance, reduced proprioception, visual and vestibular disturbances, gastrointestinal problems, and musculoskeletal disorders. Epidemiological evidence supports the link between WBV and headache and head discomfort, but few experimental studies have examined this relationship, particularly with increased muscle tension, as an intermediary. This study aimed to investigate the relationship between muscle tension and vibration intensity, between perceived neck pain and headache/head discomfort and vibration intensity, and between muscle tension and reported neck pain and headache symptoms from simulated WBV based on field measurements of all-terrain vehicle operation on farm terrain. We observed significantly higher electromyography amplitude in the High condition (equivalent to EU Directive's Exposure Limit Value) compared to both Low (equivalent to EU Directive's Exposure Action Value) and Control (quiet sitting) conditions at the left upper trapezius muscle but there were no significant time effects. Neck pain and headache/head discomfort significantly increased after both Low (91% increase from baseline) and High (154% increase from baseline) vibration conditions but there were no significant differences between conditions. Based on simple regression modeling, the relationship between muscle activity and neck pain or headache was very weak (R2 = 0-0.093). Given the possibility of multiple factors contributing to headache symptoms, future research should not only consider the role of muscle tension but also sensory conflict, excessive noise, biodynamic responses, and a combination of these factors.

Exploring Headaches in Pediatric Behçet Disease: Prevalence, Clinical Impact, and Management

Behçet's Disease (BD), also recognized as Behçet Syndrome, manifests uniquely in pediatric populations as Pediatric Behçet's Disease (PBD), characterized by multisystemic inflammatory symptoms including recurrent oral and genital aphthae, and diverse ocular, vascular, and neurological involvements. This review elucidates the prevalence, burden, and management strategies of headaches in children with PBD, focusing on both primary headaches, such as migraine and tension-type headaches, and secondary headaches linked to systemic disease manifestations. It explores the pathophysiological underpinnings specific to PBD-related headaches and discusses the intricate relationship between systemic inflammatory processes and neurological symptoms. By examining the literature from 2004 to 2024, this study highlights the high frequency of headache in PBD patients, underscoring its diagnostic and clinical significance. We aim to provide a detailed understanding of headache management in PBD, emphasizing tailored therapeutic strategies that address the unique challenges faced by this patient population. This review also underscores the importance of comprehensive clinical evaluations to optimize outcomes and mitigate long-term sequelae, proposing that awareness and understanding of headache in PBD can significantly enhance both diagnosis and management.

The Environment and Headache: a Narrative Review

PURPOSE OF REVIEW

In this narrative review, we summarize the peer-reviewed literature published between 2017 and 2022 that evaluated ambient environmental risk factors for primary headache disorders, which affect more than half of the population globally. Primary headache disorders include migraine, tension-type headache (TTH), and trigeminal and autonomic cephalalgias (TAC).

RECENT FINDINGS

We identified 17 articles that met the inclusion criteria via PubMed or Google Scholar. Seven studies (41%) relied on data from US populations. The remaining studies were conducted in China, Taiwan, Germany, Ghana, Japan, the Netherlands, South Korea, and Turkey. Air pollution was the most frequently assessed environmental risk factor. Most studies were cross-sectional and focused on all-cause or migraine headaches; one study included TTH, and none included TAC. Short-term exposure to fine particulate matter (PM2.5) was not consistently associated with headache endpoints, but long-term exposure to PM2.5 was associated with migraine headache prevalence and severity across multiple studies. Elevated ambient temperature, changes in weather, oil and gas well exposure, and less natural greenspace, but not noise pollution, were also associated with headache. No studies considered water pollution, metal exposure, ultrafine particulate matter, or wildfire smoke exposure. There is a need for ongoing research focused on headache and the environment. Study designs with the greatest explanatory power may include longitudinal studies that capture the episodic nature of headache and case-crossover analysis, which control for time-invariant individual-level confounders by design. There is also a clear need for research that considers comorbid psychiatric illness and socioeconomic position as powerful modifiers of the effect of the environment on headache.

Exploring the link between pediatric headaches and environmental noise exposure

BACKGROUND

Headaches are the most common neurologic symptoms in the pediatric population. Most primary headache in children and adolescents focuses on associated factors, including noise. Auditory discomfort is related to recognizing the pain. We aimed to analyze the headache profile of pediatric populations and the connection between noise exposure and head pain in children and adolescents.

METHODS

We reviewed retrospectively medical records of the pediatric population with headaches in Gyeongsang National University Changwon Hospital from January 2022 to April 2023. Personal headache profiling from self-questionnaires and environmental noise data from the National Noise Information System (NNIS) were used to analyze each variable, and chi-square tests and linear regression models by SAS were used to analyze the statistical correlation.

RESULTS

Of the 224 participants, 125 were clinically diagnosed with headaches. Of the 104 pubertal subjects, 56.7% were diagnosed with headaches, compared to 60% in the prepubertal group. Both daytime and nighttime noise was significantly higher in the diagnosed headache group than in the non-diagnosed group. Headache duration increased by daytime and nighttime noise with statistical significance in age-adjusted models.

CONCLUSION

We found that noise exposure is correlated to headaches in children and adolescents. Daytime and nighttime environmental noise exposure was significantly associated with the duration of headaches through our data. Therefore, we assume that noise exposure is vitally relevant to prolonged headaches in the pediatric population. Further research is needed to improve our data.

Expressed Beliefs about the Cause of Pain in a Pediatric Population: A Qualitative Study

(1) Background: The aims of this study are to explore what beliefs children and adolescents manifest about the cause of the pain they describe, to compare whether there are differences between beliefs by age and the persistence of pain, and to relate the explanations of the cause of pain with current scientific evidence. (2) Methods: a cross-sectional qualitative study was used. The primary endpoint of the study was obtaining explanations of the cause of pain recorded by means of an open-ended question. The participants were school-age children attending a charted school in the province of Barcelona. (3) Results: The children and adolescents proposed a diverse range of explanations for the cause of pain that they reported in their responses. The most frequent explanation for the cause of pain were pathologies and injuries (45.95%), ergonomic issues (22.60%) and psychological issues (15.95%). (4) Conclusions: There is a lot of variety in the explanations that young people give about the cause of their pain in schoolchildren aged between 10 and 16 years old. There exists a high prevalence of explanations non-associated with tissue damage (ENAD) concerning the causes of pain described. It is necessary that future health prevention programs dedicated to early ages consider which beliefs about the cause of pain are the most frequent in the pediatric population.

Learning headache triggers through experience: A laboratory study

OBJECTIVE

To examine how individuals may learn headache trigger beliefs through sequential symbolic pairings of trigger candidates and headache attacks.

BACKGROUND

Learning from experience may be a major source of information about headache triggers. Little is known about learning-based influences on the establishment of trigger beliefs.

METHODS

This cross-sectional, observational study included N = 300 adults with headache who participated in a laboratory computer task. First, participants rated the chances (0%-100%) that encountering specific triggers would lead to experiencing a headache. Then, 30 sequential images with the presence or absence of a common headache trigger were presented alongside images representing the presence or absence of a headache attack. The primary outcome measure was the cumulative association strength rating (0 = no relationship to 10 = perfect relationship) between the trigger and headache using all previous trials.

RESULTS

A total of N = 296 individuals completed 30 trials for each of three triggers, yielding 26,640 total trials for analysis. The median [25th, 75th] association strength ratings for each of the randomly presented headache triggers were 2.2 [0, 3] for the Color Green, 2.7 [0, 5] for Nuts, and 3.9 [0, 8] for Weather Changes. There was a strong association between the "true" cumulative association strength and corresponding ratings. A 1-point increase on the phi scale (i.e., no relationship to perfect relationship) was associated with a 1.20 (95% CI: 0.81 to 1.49, p < 0.0001) point increase in association strength rating. A participant's prior belief about the potency of a trigger affected their perceived rating of the accumulating evidence, accounting for 17% of the total variation.

CONCLUSION

In this laboratory task, individuals appeared to learn trigger-headache associations through repeated exposures to accumulating symbolic evidence. Prior beliefs about the triggers appeared to influence ratings of the strength of relationships between triggers and headache attacks.

Galcanezumab effects on incidence of headache after occurrence of triggers, premonitory symptoms, and aura in responders, non-responders, super-responders, and super non-responders

BACKGROUND

The goal of this observational, open-label, cohort study was to determine whether prophylactic migraine treatment with galcanezumab, a peripherally acting drug, alters the incidence of premonitory symptoms, and/or occurrence of headache after exposure to triggers or aura episodes in treatment-responders (≥ 50% reduction in monthly migraine days [MMD]), super-responders (≥ 70%), non-responders (< 50%) and super non-responders (< 30%).

METHODS

Participants were administered electronic daily headache diaries to document migraine days and associated symptoms one month before and during the three months of treatment. Questionnaires were used to identify conscious prodromal and trigger events that were followed by headache prior to vs. after 3 months of treatment.

RESULTS

After 3 months of galcanezumab treatment, (a) the incidence of premonitory symptoms that were followed by headache decreased by 48% in the 27 responders vs. 28% in the 19 non-responders, and by 50% in the 11 super-responders vs. 12% in the 8 super non-responders; (b) the incidence of visual and sensory aura that were followed by headache was reduced in responders, non-responders, and super-responders, but not in super non-responders; (c) the number of triggers followed by headache decreased by 38% in responders vs. 13% in non-responders, and by 31% in super-responders vs. 4% in super non-responders; and (d) some premonitory symptoms (e.g., cognitive impairment, irritability, fatigue) and triggers (e.g., stress, sleeping too little, bright light, aura) were followed by headache only in super non-responders.

CONCLUSIONS

Mechanistically, these findings suggest that even a mild decrease in migraine frequency is sufficient to partially reverse the excitability and responsivity of neurons involved in the generation of certain triggers and potentially premonitory symptoms of migraine.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04271202. Registration date: February 10, 2020.

Avoid or seek light - a randomized crossover fMRI study investigating opposing treatment strategies for photophobia in migraine

Background

Photophobia, the aberrantly increased sensitivity to light, is a common symptom in migraine patients and light discomfort is frequently found as a trigger for migraine attacks. In behavioral studies, planned exposure to light was found to reduce headache in migraine patients with photophobia, potentially by increasing habituation to this migraine trigger. Here, we aimed to elucidate neurophysiological mechanisms of light exposure versus light deprivation in migraine patients using functional magnetic resonance imaging (fMRI).

Methods

Ten migraine patients (9 female, age = 28.70 ± 8.18 years) and 11 healthy controls (9 female, age = 23.73 ± 2.24 years) spent one hour on 7 consecutive days exposed to flashing light (Flash) or darkness (Dark) using a crossover design with a wash-out period of 3 months. Study participants kept a diary including items on interictal and ictal photophobia, presence and severity of headache 7 days before, during and 7 days after the interventions. One week before and one day after both interventions, fMRI using flickering light in a block design was applied. Functional activation was analyzed at whole-brain level and habituation of the visual cortex (V1) was modeled with the initial amplitude estimate and the corrected habituation slope.

Results

Mean interictal photophobia decreased after both interventions, but differences relative to the baseline did not survive correction for multiple comparisons. At baseline, flickering light induced activation in V1 was higher in the patients compared to the controls, but activation normalized after the Flash and the Dark interventions. V1 habituation indices correlated with headache frequency, headache severity and ictal photophobia. In the Flash condition, the individual change of headache frequency relative to the baseline corresponded almost perfectly to the change of the habituation slope compared to the baseline.

Conclusions

On average, light exposure did not lead to symptom relief, potentially due to the short duration of the intervention and the high variability of the patients’ responses to the intervention. However, the strong relationship between visual cortex habituation and headache symptoms and its modulation by light exposure might shed light on the neurophysiological basis of exposure treatment effects.

Trial registration

NCT05369910 (05/06/2022, retrospectively registered).

Bimodal sensory integration in migraine: A study of the effect of visual stimulation on somatosensory evoked cortical responses

BACKGROUND

Merging of sensory information is a crucial process for adapting the behaviour to the environment in all species. It is not known if this multisensory integration might be dysfunctioning interictally in migraine without aura, where sensory stimuli of various modalities are processed abnormally when delivered separately. To investigate this question, we compared the effects of a concomitant visual stimulation on conventional low-frequency somatosensory evoked potentials and embedded high-frequency oscillations between migraine patients and healthy volunteers.

METHODS

We recorded somatosensory evoked potentials in 19 healthy volunteers and in 19 interictal migraine without aura patients before, during, and 5 min after (T2) simultaneous synchronous pattern-reversal visual stimulation. At each time point, we measured amplitude and habituation of the N20-P25 low-frequency-somatosensory evoked potentials component and maximal peak-to-peak amplitude of early and late bursts of high-frequency oscillations.

RESULTS

In healthy volunteers, the bimodal stimulation significantly reduced low-frequency-somatosensory evoked potentials habituation and tended to reduce early high-frequency oscillations that reflect thalamocortical activity. By contrast, in migraine without aura patients, bimodal stimulation significantly increased low-frequency-somatosensory evoked potentials habituation and early high-frequency oscillations. At T2, all visual stimulation-induced changes of somatosensory processing had vanished.

CONCLUSION

These results suggest a malfunctioning multisensory integration process, which could be favoured by an abnormal excitability level of thalamo-cortical loops.

Perceptions of Modulatory Factors in Migraine and Epilepsy: A Multicenter Study

Background: Migraine and epilepsy are both common episodic disorders, typically precipitated or inhibited by some modulatory factors (MFs). Objective: To assess the self-perception of MFs in patients with migraine (PWM) compared to patients with epilepsy (PWE) with a standardized protocol in different countries. Methods: Transcultural multicenter comparative cross-sectional study. All consecutive patients who fulfilled the ICHD-3 criteria for migraine and ILAE's criteria for epilepsy, with at least 1 year of follow-up were interviewed with a semi-structured questionnaire on clinical and epidemiological data and were asked to identify all experienced MFs from a provided list. Results: A total of 608 individuals were surveyed at five university referral centers in Brazil, Guatemala, Lithuania and Turkey. Two hundred and nineteen (91.6%) PWM and 305 (82.7%) PWE identified attack precipitating factors (PFs; p < 0.001). The most frequent three PFs reported by epilepsy patients were: "lack of sleep" (56.6%), "emotional stress" (55.3%), "negative feelings" (53.9%), while among migraine patients "emotional stress" (81.6%), "lack of sleep" (77.8%), "negative feelings" (75.7%) were cited. Inhibitory factors (IFs) for the episodes were reported by 68 (28.5%) PWM and 116 (31.4%) PWE. "Darkness" was the most common one, described by 35.6% of PWM whereas "positive feelings" reported by 10.6% of PWE. Most MFs are concordant across the countries but some transcultural differences were noted. Conclusion: The MFs of migraine and epilepsy attacks and their varying frequencies according to different countries were investigated with the same standardized questionnaire, for the first time. MFs were recognized very often in both migraine and epilepsy cohorts, but in distinct disease-specific prevalence, being more frequent in migraine. Recognition of self-perceived MFs may be helpful for the management of both illnesses.

Residential traffic noise exposure and headaches: Results from the population-based heinz nixdorf recall study

Context and aim

The link between headaches and exposure to loud noise in occupational settings has been established. However, the effect of less intense but chronic residential traffic noise exposure on headache occurrence is less clear.

Settings and design

We included 3,025 participants from the Heinz Nixdorf Recall study in Germany for this cross-sectional analysis.

Methods and material

Residential road traffic noise exposure at the 2006-2008 address was modelled in A-weighted decibels (dB(A)) according to the European Noise Directive (2002/49/EC) for 24-hour (L_den) and night-time noise (22-6 h, L_night). Indoor traffic noise exposure was obtained by modifying L_den and L_night based on residence orientation, window type, and personal window opening habits. Traffic noise exposure below 55, 45 dB(A), 35 and 25 dB(A) were set as the reference for L_den, L_night, L_den,indoor and L_night,indoor, respectively. Average number of days with headache per month over the past three months was ascertained during the follow-up (2011-2015) medical interview.

Statistical analysis used

Prevalence Odds Ratios (POR) of having eight or more headaches per month per 5 dB(A) increase in traffic noise exposure were calculated using logistic regression, adjusting for age, sex, sport, number of chronic conditions, years of education and smoking status.

Results

The mean age of participants was 58.3. Mean L_den was 54 dB(A). Median monthly headache days was one. No association was seen between traffic noise exposure and having ≥8 headaches/month for all the examined traffic noise indicators. However, traffic noise was positively associated with traffic noise-annoyance and insomnia; and night-time traffic noise-annoyance and insomnia were positively associated with headache.

Conclusion

In conclusion, our data did not provide any evidence for an association between chronic traffic noise exposure and prevalence of headaches at this population's exposure levels. This should be explored in different populations given that this is the first study of its type and that noise exposure was generally low in our population.

Approximation to pain-signaling network in humans by means of migraine

Nociceptive signals are processed within a pain-related network of the brain. Migraine is a rather specific model to gain insight into this system. Brain networks may be described by white matter tracts interconnecting functionally defined gray matter regions. Here, we present an overview of the migraine-related pain network revealed by this strategy. Based on diffusion tensor imaging data from subjects in the Human Connectome Project (HCP) database, we used a global tractography approach to reconstruct white matter tracts connecting brain regions that are known to be involved in migraine-related pain signaling. This network includes an ascending nociceptive pathway, a descending modulatory pathway, a cortical processing system, and a connection between pain-processing and modulatory areas. The insular cortex emerged as the central interface of this network. Direct connections to visual and auditory cortical association fields suggest a potential neural basis of phono- or photophobia and aura phenomena. The intra-axonal volume (Vintra ) as a measure of fiber integrity based on diffusion microstructure was extracted using an innovative supervised machine learning approach in form of a Bayesian estimator. Self-reported pain levels of HCP subjects were positively correlated with tract integrity in subcortical tracts. No correlation with pain was found for the cortical processing systems.

Double-Containment Coil With Enhanced Winding Mounting for Transcranial Magnetic Stimulation With Reduced Acoustic Noise

OBJECTIVE

This work aims to reduce the acoustic noise level of transcranial magnetic stimulation (TMS) coils. TMS requires high currents (several thousand amperes) to be pulsed through the coil, which generates a loud acoustic impulse whose peak sound pressure level (SPL) can exceed 130 dB(Z). This sound poses a risk to hearing and elicits unwanted neural activation of auditory brain circuits.

METHODS

We propose a new double-containment coil with enhanced winding mounting (DCC), which utilizes acoustic impedance mismatch to contain and dissipate the impulsive sound within an air-tight outer casing. The coil winding is potted into a rigid block, which is mounted to the outer casing through the block´s acoustic nodes that are subject to minimum vibration during the pulse. The rest of the winding block is isolated from the casing by an air gap, and the sound is absorbed by polyester fiber panels within the casing. The casing thickness under the winding center is minimized to maximize the electric field output.

RESULTS

Compared to commercial figure-of-eight TMS coils, the DCC prototype has 18-41 dB(Z) lower peak SPL at matched stimulation strength, whilst providing 28% higher maximum stimulation strength than equally focal coils.

CONCLUSION

The DCC design greatly reduces the acoustic noise of TMS while increasing the achievable stimulation strength.

SIGNIFICANCE

The acoustic noise reduction from our coil design is comparable to that provided by typical hearing protection devices. This coil design approach can enhance hearing safety and reduce auditory co-activations in the brain and other detrimental effects of TMS sound.

Triggers of Primary Headaches: Issues and Pathways Forward

The triggers of primary headaches have considerable significance for our understanding and management of headache and migraine. Triggers explain the variance in headaches - why they occur when they do. Trigger management is generally viewed as an important component of a comprehensive treatment approach for headaches. Historically, however, triggers have not had a prominent place in the headache literature. This situation began to change 20 to 30 years ago, and the pace of change has increased exponentially in recent times. Nevertheless, the field is beset with issues that have held it back from achieving more. This review will focus on elaborating those issues with the goal of suggesting ways forward. The first issue considered will be the definition of a trigger, and how specific triggers are labeled. Consideration will then be given to a classification system for triggers. The review will discuss next the evidence relating to whether self-reported triggers can, indeed, precipitate headaches, and how the capacity to elicit headaches may be acquired or extinguished. Attention will be given to the very important clinical issue of trigger management. Finally, the pathways forward will be proposed. Perhaps the most useful thing to accomplish at this point in time would be agreement on a definition of headache triggers, a list of triggers, and a classification system for triggers. This would greatly assist in comparing research on triggers from different research groups as well as eliminating some of the issues identified in this review. An authoritative body such as the American Headache Society or the International Headache Society, could establish a multidisciplinary committee that would complete these tasks. Consideration should also be given to incorporating triggers into the International Classification of Headache Disorders as an axis or via the use of codes, as this would raise the profile of triggers in assessment and management.

Fear, Avoidance, and Disability in Headache Disorders

PURPOSE OF REVIEW

The purpose of this review is to summarize the role of avoidance behavior in headache-related disability and overview relevant clinical implications.

RECENT FINDINGS

Avoidance occupies a central role in contemporary psychological perspectives on headache disorders and other chronic pain conditions. Several cognitive constructs of relevance to headache are influenced and maintained by avoidance behavior. A growing body of literature attests to the notion that avoidance of headache triggers, of stimuli that exacerbate headache, and of broader life domains can negatively affect headache progression, disability/quality of life, and comorbid psychiatric symptoms. Interventions targeting avoidance behavior, such as therapeutic exposure to headache triggers, mindfulness, and acceptance and commitment therapy (ACT), hold promise for headache disorders but need to be tested in larger trials. Researchers and clinicians are encouraged to attend to functional impairment as a critically important treatment outcome. Comprehensive understanding of headache disorders necessitates attention not merely to diagnostic symptoms and their reduction, but to patterns of avoidance behavior that inadvertently exacerbate headache and contribute to functional impairment.

Association Between Occupational Physicochemical Exposures and Headache/Eyestrain Symptoms Among Korean Indoor/Outdoor Construction Workers

Background

Headache/eyestrain symptoms are common health problems that people experience in daily life. Various studies have examined risk factors contributing to headache/eyestrains, and physicochemical exposure was found to be a leading risk factor in causing such symptoms. The purpose of this study was to examine the relationship of headache/eyestrain symptoms with physicochemical exposure among Korean construction workers depended on worksite.

Methods

This study used data from the 4th Korean Workers Conditions Survey and selected 1,945 Korean construction workers as participants. Multivariable logistic regression analysis was used to determine the relationship.

Results

Exposure to vibrations among all construction workers affected the moderate exposure group [odds ratio (OR) 1.53, 95% confidence interval (CI) 1.01–2.32], the high exposure group (OR 1.77 95%CI 1.17–2.67), and the indoor high exposure group (OR 1.61, 95%CI 1.02-2.55) and among outdoor construction workers, the moderate group (OR 6.61, 95%CI 15.4–28.48) and the high group (OR 6.61, 95%CI 1.56–27.98). When exposed to mist, dust, and fumes, the indoor high exposure group was significantly affected (OR 1.63, 95%CI 1.07–2.47). All construction workers exposed to organic solvents were affected, high exposure group (OR 1.69, 95%CI 1.15–2.49) and indoor high exposure group (OR 1.77, 95%CI 1.08–2.89). The high exposure group in all construction worker (OR 1.70, 95%CI 1.20–2.42) and the indoor high exposure group (OR 1.83, 95%CI 1.17–2.89) also were affected by secondhand smoking exposure.

Conclusion

Many physicochemical exposure factors affect headache/eyestrain symptoms among construction workers, especially indoor construction workers, suggesting a deficiency in occupational hygiene and health environments at indoor construction worksites.

Sensory Modulation Disorder (SMD) and Pain: A New Perspective

Sensory modulation disorder (SMD) affects sensory processing across single or multiple sensory systems. The sensory over-responsivity (SOR) subtype of SMD is manifested clinically as a condition in which non-painful stimuli are perceived as abnormally irritating, unpleasant, or even painful. Moreover, SOR interferes with participation in daily routines and activities (Dunn, 2007; Bar-Shalita et al., 2008; Chien et al., 2016), co-occurs with daily pain hyper-sensitivity, and reduces quality of life due to bodily pain. Laboratory behavioral studies have confirmed abnormal pain perception, as demonstrated by hyperalgesia and an enhanced lingering painful sensation, in children and adults with SMD. Advanced quantitative sensory testing (QST) has revealed the mechanisms of altered pain processing in SOR whereby despite the existence of normal peripheral sensory processing, there is enhanced facilitation of pain-transmitting pathways along with preserved but delayed inhibitory pain modulation. These findings point to central nervous system (CNS) involvement as the underlying mechanism of pain hypersensitivity in SOR. Based on the mutual central processing of both non-painful and painful sensory stimuli, we suggest shared mechanisms such as cortical hyper-excitation, an excitatory-inhibitory neuronal imbalance, and sensory modulation alterations. This is supported by novel findings indicating that SOR is a risk factor and comorbidity of chronic non-neuropathic pain disorders. This is the first review to summarize current empirical knowledge investigating SMD and pain, a sensory modality not yet part of the official SMD realm. We propose a neurophysiological mechanism-based model for the interrelation between pain and SMD. Embracing the pain domain could significantly contribute to the understanding of this condition’s pathogenesis and how it manifests in daily life, as well as suggesting the basis for future potential mechanism-based therapies.

Identification of Everyday Sounds Perceived as Noise by Migraine Patients

Objective Sound hypersensitivity is highly comorbid with migraine headaches. To elucidate the pathogenic mechanism of migraine attacks, we must first identify the types of everyday environmental sounds they perceive as unpleasant and clarify the acoustic properties of such sounds. This study aimed to clarify the true nature of "noise," i.e. everyday sounds perceived as unpleasant by migraineurs, by evaluating their subjective comfort/discomfort in response to several sounds commonly heard in everyday life. Methods Participants were presented with 20 environmental sounds they would likely hear daily. Subjects rated the pleasantness/unpleasantness of each stimulus using a nine-step scale. Patients We recruited 50 adults with migraine headaches (46 women, 4 men) and 50 healthy controls (35 women, 15 men). Results Migraineurs provided statistically significantly lower (more unpleasant) ratings to ambulance sirens, police car sirens, and railroad crossing bells than did controls. Our analysis also investigated the acoustic characteristics associated with higher rating gaps between the two groups. Greater divergence in ratings for the same stimulus was associated with less power (smaller amplitude envelope) and slower temporal variation in signals in the 400-Hz band. Conclusion We identified specific signal components associated with different subjective (un) pleasantness scores between migraineurs and healthy adults, which may lead to the elucidation of the pathogenic mechanism underlying migraine attacks triggered by sound.

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.

Headache Triggers as Surprise

OBJECTIVES

To examine the hypothesis that surprising experiences of headache triggers are associated with daily headache activity.

BACKGROUND

Little is known about the specific environmental or behavioral interactions that might trigger a headache attack in a prone individual. We propose that headache trigger exposures can be usefully characterized, not only by their mechanisms of action, but also on the degree of "surprise" they present to the individual. This hypothesis is based on elements of information theory: that unusual events and experiences carry more information than common events and experiences and that headache attacks are associated with reactions to uncommon or unexpected biopsychosocial exposures.

METHODS

A secondary analysis of the Headache Prediction Study, this prospective cohort study followed N = 95 individuals with episodic migraine who contributed 4195 days of diary data. Information was collected on daily levels of several common headache triggers: number of caffeinated beverages, number of alcoholic beverages, stress (Daily Stress Inventory), and mood disturbance (Profile of Mood States). The probability of observing variations in each trigger was used to estimate the "surprisal" of experiencing each trigger, and this information, measured in bits, was used to predict headache attacks.

RESULTS

Participants experienced a headache attack on 1613 of 4195 days (38.5%). Each of the triggers was modestly related to the probability of experiencing a future headache in a complex manner that involved interactions between current headache status, current levels of the trigger, and lagged (previous) levels of the trigger. However, when expressed as a surprisal, the associations were simplified and strengthened. For example, each of the individual trigger surprisals exhibited a meaningful association with the development of a future headache attack (expressed as a 1 SD change in surprisal), with odds ratios ranging from a low of 1.11 (95%CI: 1.00 to 1.24) for alcohol to a high of 1.30 (95%CI: 1.14 to 1.46) for stress. The individual surprisals could be summed for total trigger surprise and exhibited a reliable association with new onset headache, OR 1.35 (95%CI: 1.17 to 1.49). This score exhibited superior discrimination between headache and non-headache days from all of the individual triggers (ignoring base rate, AUC: 0.61; AUC: 0.71 with base rate).

CONCLUSIONS

Diverse headache triggers can be uniformly described using their probability distributions. Rare values of headache triggers, or surprising values, were found to have consistent associations with headache activity across a variety of triggers. This finding, if validated in external data using other triggers, has potential to be used to conceptualize the influence of a wide range of headache triggers.

Neurobiology of Photophobia

BACKGROUND

Photophobia is commonly associated with migraine, meningitis, concussion, and a variety of ocular diseases. Advances in our ability to trace multiple brain pathways through which light information is processed have paved the way to a better understanding of the neurobiology of photophobia and the complexity of the symptoms triggered by light.

PURPOSE

The purpose of this review is to summarize recent anatomical and physiological studies on the neurobiology of photophobia with emphasis on migraine.

RECENT FINDINGS

Observations made in blind and seeing migraine patients, and in a variety of animal models, have led to the discovery of a novel retino-thalamo-cortical pathway that carries photic signal from melanopsinergic and nonmelanopsinergic retinal ganglion cells (RGCs) to thalamic neurons. Activity of these neurons is driven by migraine and their axonal projections convey signals about headache and light to multiple cortical areas involved in the generation of common migraine symptoms. Novel projections of RGCs into previously unidentified hypothalamic neurons that regulate parasympathetic and sympathetic functions have also been discovered. Finally, recent work has led to a novel understanding of color preference in migraine-type photophobia and of the roles played by the retina, thalamus, and cortex.

SUMMARY

The findings provide a neural substrate for understanding the complexity of aversion to light in patients with migraine and neuro-ophthalmologic other disorders.

Color-selective photophobia in ictal vs interictal migraineurs and in healthy controls

Aversion to light is common among migraineurs undergoing acute attacks. Using psychophysical assessments in patients with episodic migraine, we reported that white, blue, amber, and red lights exacerbate migraine headache in a significantly larger percentage of patients and to a greater extent compared with green light. This study aimed at determining whether these findings are phase-dependent-namely, manifested exclusively during migraine (ictally) but not in its absence (interictally), or condition-dependent-ie, expressed uniquely in migraineurs but not in healthy controls. To determine whether the color preference of migraine-type photophobia is phase- or condition-dependent, we compared the effects of each color of light in each intensity between migraineurs during and in-between attacks and healthy controls. During the ictal and interictal phases, the proportion of migraineurs reporting changes in headache severity when exposed to the different colors of light increased in accordance with elevated light intensities. During the ictal phase, white, blue, amber, and red lights exacerbated headaches in ∼80% of the patients; however, during the interictal phase, light initiated headache in only 16% to 19%. Notably, green light exacerbated headaches in 40% and triggered headaches in 3% of the patients studied during the ictal and interictal phases, respectively. With one exception (highest red light intensity), no control subject reported headache in response to the light stimuli. These findings suggest that color preference is unique to migraineurs-as it was not found in control subjects-and that it is independent of whether or not the patients are in their ictal or interictal phase.

The relationship between occupational noise and vibration exposure and headache/eyestrain, based on the fourth Korean Working Condition Survey (KWCS)

INTRODUCTION

The individual and combined effect of occupational noise and vibration exposures, on workers' health has not been thoroughly investigated. In order to find better ways to prevent and manage workers' headache, this study aimed to investigate the effects of occupational noise and vibration exposure on headache/eyestrain.

METHODS

We used data from the fourth Korean Working Condition Survey (2014). After applying inclusion and exclusion criteria, 25,751 workers were included. Occupational noise and vibration exposure and the prevalence of headache/eyestrain were investigated by self-reported survey. Chi-square tests were used to compare differences in baseline characteristics between the group with headache/eyestrain and the group without. Odds ratios and 95% confidence intervals were estimated using a logistic regression model adjusted for several covariates. Area under the receiver operating characteristics curve (AUROC) analysis was used to evaluate the effect of occupational noise and/or vibration exposure.

RESULTS

Among the 25,751 study subjects, 4,903 had experienced headache/eyestrain in the preceding year. There were significant differences in age, education level, household income, occupational classification, shift work, occupational vibration exposure, and occupational noise exposure between the two groups (all p<0.05). The odds ratios between each exposure and headache/eyestrain increased proportionally with the level of exposure, increasing from 1.08 to 1.26 with increasing vibration exposure, and from 1.25 to 1.41 with increasing noise exposure. According to the AUROC analysis, the predictive power of each exposure was significant, and increased when the two exposures were considered in combination.

DISCUSSION

The findings of this study show that both occupational noise and vibration exposures are associated with headache/eyestrain; noise exposure more strongly so. However, when the two exposures are considered in combination, the explanatory power for headache/eyestrain is increased. Therefore, efforts aimed at reducing and managing occupational noise and vibration exposure are crucial to maintaining workers' health.

Association of posttraumatic stress disorder symptoms with migraine and headache after a natural disaster

OBJECTIVE

Previous research shows that migraine and general headache symptoms increase after traumatic events. Questions remain about whether posttraumatic stress disorder (PTSD) produces migraine/headache symptoms, or if individuals afflicted by migraine/headache are especially likely to develop PTSD. We test whether PTSD symptoms following a natural disaster are associated with higher odds of reporting frequent headaches/migraines postdisaster. We decompose PTSD into intrusion, avoidance, and hyperarousal symptom clusters to examine which, if any, are uniquely related to headache/migraine postdisaster.

METHOD

We use prospectively collected pre- and postdisaster data to explore whether overall PTSD symptoms and symptom clusters are associated with migraine/headache in a sample of Hurricane Katrina survivors. We account for severity of hurricane exposure and control for baseline migraine and headache problems to reduce the probability that heightened PTSD susceptibility among those who already suffered from the conditions could explain observed associations.

RESULTS

PTSD symptoms were associated with higher odds of experiencing frequent headaches or migraines with a standard deviation change in PTSD score corresponding to over twice the odds (95% confidence interval [1.64, 2.68]) of having trouble with frequent headaches or migraines in the post-Katrina period. Each additional point on the intrusion subscale (sample M [SD] = 1.6 [1.1]) was associated with 55% higher odds of reporting frequent headache/migraine (95% confidence interval [1.03, 2.33]), but we found no association with avoidance or hyperarousal symptoms.

CONCLUSIONS

Clinicians and disaster planners should be aware that disaster survivors might be at heightened risk of migraine/headache episodes, and those experiencing intrusive reminders may be most affected. (PsycINFO Database Record

The Headache Triggers Sensitivity and Avoidance Questionnaire: Establishing the Psychometric Properties of the Questionnaire

OBJECTIVE

The purpose of this study was to evaluate the psychometric properties of the newly developed Headache Triggers Sensitivity and Avoidance Questionnaire (HTSAQ) designed to measure variables relating to the Trigger Avoidance Model of Headaches.

BACKGROUND

The Trigger Avoidance Model of Headaches proposes that one pathway to developing a primary headache disorder is through the avoidance of headache triggers, resulting in an increase in trigger potency through sensitization. Conversely, prolonged exposure to certain triggers may reduce a potential trigger's ability to precipitate a headache. This model has led to an alternative approach to trigger management being proposed called Learning to Cope with Triggers, which advocates the desensitization of certain headache triggers through controlled exposure, while supporting avoidance of those triggers that are detrimental to health and wellbeing. To be able to evaluate predictions based on the Trigger Avoidance Model of Headaches and to investigate the effectiveness of Learning to Cope with Triggers, psychometrically sound measures of trigger sensitivity and trigger avoidance are needed.

METHOD

A convenience sample of 376 participants (87.5% female; 64.1% European descent) was recruited for the online study which consisted of a battery of measures including the HTSAQ, Brief Headache Screen, Pain Anxiety Symptoms Scale, Pain Sensitivity Questionnaire, Chronic Pain Acceptance Questionnaire, and demographic items. With an interval of 2-6 weeks, a subsample of participants (n = 201) completed the HTSAQ for a second time. The mean age of the sample was 31.4 years (SD = 12.8). The most common headache diagnoses (based on the Brief Headache Screen) were migraine (chronic = 62; episodic = 160), followed by medication-overuse headache (n = 87). The remaining participants (n = 67) were diagnosed as having episodic less severe headache (most likely tension-type headache).

RESULTS

Reliability was assessed through internal consistency and test-retest reliability over a period of 2-6 weeks, and both were excellent (alpha > .80). Strong construct validity was demonstrated by the measure's scale scores being significantly correlated in theoretically consistent ways with the Pain Sensitivity Questionnaire, Pain Anxiety Symptoms Scale, and Chronic Pain Acceptance Questionnaire. As the Trigger Avoidance Model of Headaches would predict, correlations between the HTSAQ Sensitivity scales and the Avoidance scale were strong (P < .001), and participants with chronic migraine had significantly higher HTSAQ scores than those with episodic headaches.

CONCLUSION

The findings support the use of the HTSAQ as a valid and reliable tool for assessing sensitivity to headache triggers and avoidance of headache triggers. Further research examining the factor structure of the HTSAQ is warranted.

Efficacy of Diet Restriction on Migraines

Introduction

Migraine is a common type of headache, but its pathogenesis is still not fully understood. Triggering factors may vary in migraine patients with a particular importance of certain food intake. In this study, the efficacy of limiting certain migraine- triggering foods in the prevention of migraine attacks was investigated.

Methods

Patients diagnosed with migraine without aura according to the International Classification of Headaches were enrolled. Fifty migraine patients stating that migraine attack started after the intake of certain foods were evaluated. The patients were randomly divided into 2 groups. The migraine-triggering foods identified by the patients were excluded from the diet in both groups 1 (n=25) and 2 (n=25). Monthly attack frequency, attack duration, and attack severity (using the visual analogue scale) were recorded before starting the diet restriction and 2 months after the diet restriction. Diet restriction was relaxed in group 1 after the second month and continued in group 2. In the fourth month, the monthly attack frequency, attack duration, and attack severity (using the visual analogue scale) were determined in both groups.

Results

A total of 50 patients comprising 9 males and 41 females were evaluated in this study. In both the groups, in the second month after diet implementation, monthly attack frequency, attack duration, and attack severity were found to have decreased to a statistically significant extent compared to those in the period before diet implementation [group 1 (p=0.011, p=0.041, and p=0.003, respectively) and group 2 (p=0.015, p=0.037, and p=0.003, respectively)]. In the evaluation in the fourth month, it was observed that this significant decrease was maintained only in group 2.

Conclusion

The results of the study reveal that if migraine-triggering foods are identified by migraine patients, restricting their intake can be an effective and reliable method to reduce migraine attacks.

The relative importance of anxiety and depression in pain impact in individuals with migraine headaches

BACKGROUND

Psychological factors are thought to impact headache as triggering, maintaining, and exacerbating factors. A better understanding of the role that modifiable factors, such as anxiety or depression, play in the impact of migraine could help identify potential treatment targets in this population.

OBJECTIVES

The objective of this study was to evaluate the relative importance of anxiety and depression as predictors of the impact of migraine on function. Thus, we aim to understand the relative importance that anxiety and depression have on the impact of migraines by assessing both and some life domains.

METHODS

Cross-sectional study involving forty-three individuals, mostly females (93%), with migraine headaches aged between 20 and 60 years old. Participants answered questions about headache pain intensity at the time of data collection and the usual in the past 30 days (0-10 Numerical Rating Scales) as well as other pain characteristics (i.e., duration, frequency, and duration), headache impact (vitality and social, role, and cognitive functioning), anxiety and depression by using the Hospital Anxiety and Depression Scale.

RESULTS

Anxiety (r=0.56, p<.001), but not depression (r=0.09, p=.59), was significantly associated with headache impact. Thus showing the relative importance that anxiety has on headache impact.

CONCLUSIONS

The findings support a larger role for anxiety than depression in the impact of migraine headaches on patient function. There are a number of mechanisms by which anxiety could potentially influence the impact of headache on patient function, and this study highlights that anxiety could potentially be a trigger of headache activity.

IMPLICATIONS

The findings thus suggest the possibility that treatments that focus on anxiety might be potentially more important for individuals with migraine than treatments that focus on depression, at least with respect to having a beneficial impact on the interference of headache with activity. Research is needed to evaluate the beneficial impact of anxiety treatment in individuals with migraine headaches. Clinicians should evaluate and consider treating, as appropriate and necessary, anxiety in patients with migraine.

Behavioural Management of Headache Triggers: Three Case Examples Illustrating a New Effective Approach (Learning to Cope with Triggers)

The traditional approach to headache trigger management is to advise avoidance of all triggers, but we have advocated an alternative approach called ‘Learning to Cope with Triggers’ (LCT), in which the objective is to desensitise headache sufferers to some triggers or to build up tolerance for the triggers, using exposure techniques. A recent publication established the efficacy of this approach to trigger management. Reported here are three cases to illustrate how LCT is used in practice. Two cases were male and one was female, with ages ranging from 32 to 67 years. The headache diagnoses were frequent episodic tension-type headache, migraine without aura, and chronic tension-type headache; all had had headaches since childhood/adolescence. The headache triggers that were the focus of the intervention were heat, tiredness, and stress/anger. Post-treatment, changes in the capacity of the triggers to elicit headaches were reported in all three cases. Reductions in headaches from pre- to post-treatment, and from pre- to 4-month follow-up, were: case 1, 69% and 60% respectively; case 2, 76% and 80% respectively; and case 3, 73% and 61% respectively. Decreases in medication consumption, and enhanced self-efficacy were also recorded.

Functional MRI of migraine

Migraine is a disabling neurological condition manifesting with attacks of headache, hypersensitivities to visual, auditory, olfactory and somatosensory stimuli, nausea, and vomiting. Exposure to sensory stimuli, such as odours, visual stimuli, and sounds, commonly triggers migraine attacks, and hypersensitivities to sensory stimuli are prominent during migraine attacks, but can persist with less magnitude between attacks. Functional MRI (fMRI) has been used to investigate the mechanisms that lead to migraine sensory hypersensitivities by measuring brain responses to visual, olfactory, and painful cutaneous stimulation, and functional connectivity analyses have investigated the functional organisation of specific brain regions and networks responsible for sensory processing. These studies have consistently shown atypical brain responses to sensory stimuli, absence of the normal habituating response between attacks, and atypical functional connectivity of sensory processing regions. Identification of the mechanisms that lead to migraine sensory hypersensitivities and that trigger migraine attacks in response to sensory stimuli might help to better understand neural dysfunction in migraine and provide new targets for migraine prevention, and could provide fMRI biomarkers that indicate early responses to preventive therapy.

Enhancing cognitive-behavioural therapy for recurrent headache: design of a randomised controlled trial

Background

We have argued against the traditional approach of counselling avoidance of all triggers of headaches and migraine. Problems with this approach include the impossibility of avoiding all triggers and the high costs associated with trying to do so, and that avoidance could lead to reduced tolerance for the triggers. We have developed an alternative approach called Learning to Cope with Triggers (LCT) that encourages avoidance of triggers that are detrimental to health and wellbeing, but uses exposure to other triggers to desensitise headache sufferers to the triggers. This approach has been shown to be more effective than advising avoidance of all triggers. Trigger management is only one component of a comprehensive treatment program and the current study is designed to evaluate a new approach to treating headaches in which LCT has been integrated into an established cognitive-behavioural therapy (CBT) package (LCT/CBT).

Methods/Design

A target sample of 120 adult participants who suffer from migraine or tension-type headache, at least six days per month, and have done so for at least 12 months will be recruited. Participants will be randomly assigned to one of three groups: LCT/CBT; Avoid/CBT (CBT combined with instructions to avoid all triggers); and waiting-list control. Measures will include: daily diaries for recording headaches, triggers and medication consumption; headache disability and quality of life; trigger avoidance; locus of control and self-efficacy; and coping strategies. Treatment will involve 12 60-minute sessions scheduled weekly. Assessment will be completed before and after treatment, and at 4 and 12 month follow-up. The data will be analysed to determine which approach is most effective, and predictors of response to treatment.

Discussion

Migraine and tension-type headache are common and can be disabling. CBT has been demonstrated to be an efficacious treatment for both disorders. However, there is room for improvement. This study aims to increase the efficacy of behavioural approaches and identify factors predictive of a positive response.

Trial registration

Australian and New Zealand Clinical Trials Registry ACTRN12614000435684.

Multisensory integration in migraine

PURPOSE OF REVIEW

Migraine attacks consist of head pain and hypersensitivities to somatosensory, visual, auditory, and olfactory stimuli. Investigating how the migraine brain simultaneously processes and responds to multiple incoming stimuli may yield insights into migraine pathophysiology and migraine symptoms.

RECENT FINDINGS

The presence and intensity of hypersensitivity to one stimulus type are positively associated with the presence and intensity of hypersensitivities to other stimuli and to headache intensity. Furthermore, exposure to visual, auditory, and olfactory stimuli can trigger migraine attacks. These relationships suggest a role for multisensory integration in migraine.

SUMMARY

Multisensory integration of somatosensory, visual, auditory, and olfactory stimuli by the migraine brain may be an important concept for understanding migraine.

Migraine and triggers: post hoc ergo propter hoc?

The influence of environmental factors on the clinical manifestation of migraine has been a matter of extensive debate over the past decades. Migraineurs commonly report foods, alcohol, meteorologic or atmospheric changes, exposure to light, sounds, or odors, as factors that trigger or aggravate their migraine attacks. In the same way, physicians frequently follow this belief in their recommendations in how migraineurs may reduce their attack frequency, especially with regard to the consumption of certain food components. Interestingly, despite being such a common belief, most of the clinical studies have shown conflicting results. The aim of the review is to critically analyze clinical and pathophysiological facts that support or refute a correlation between certain environmental stimuli and the occurrence of migraine attacks. Given the substantial discrepancy between patients' reports and objective clinical data, the methodological difficulties of investigating the link between environmental factors and migraine are highlighted.

Atypical resting-state functional connectivity of affective pain regions in chronic migraine

OBJECTIVE

Chronic migraineurs (CM) have painful intolerances to somatosensory, visual, olfactory, and auditory stimuli during and between migraine attacks. These intolerances are suggestive of atypical affective responses to potentially noxious stimuli. We hypothesized that atypical resting-state functional connectivity (rs-fc) of affective pain-processing brain regions may associate with these intolerances. This study compared rs-fc of affective pain-processing regions in CM with controls.

METHODS

Twelve minutes of resting-state blood oxygenation level-dependent data were collected from 20 interictal adult CM and 20 controls. Rs-fc between 5 affective regions (anterior cingulate cortex, right/left anterior insula, and right/left amygdala) with the rest of the brain was determined. Functional connections consistently differing between CM and controls were identified using summary analyses. Correlations between number of migraine years and the strengths of functional connections that consistently differed between CM and controls were calculated.

RESULTS

Functional connections with affective pain regions that differed in CM and controls included regions in anterior insula, amygdala, pulvinar, mediodorsal thalamus, middle temporal cortex, and periaqueductal gray. There were significant correlations between the number of years with CM and functional connectivity strength between the anterior insula with mediodorsal thalamus and anterior insula with periaqueductal gray.

CONCLUSION

CM is associated with interictal atypical rs-fc of affective pain regions with pain-facilitating and pain-inhibiting regions that participate in sensory-discriminative, cognitive, and integrative domains of the pain experience. Atypical rs-fc with affective pain regions may relate to aberrant affective pain processing and atypical affective responses to painful stimuli characteristic of CM.

Causality and headache triggers

OBJECTIVE

The objective of this study was to explore the conditions necessary to assign causal status to headache triggers.

BACKGROUND

The term "headache trigger" is commonly used to label any stimulus that is assumed to cause headaches. However, the assumptions required for determining if a given stimulus in fact has a causal-type relationship in eliciting headaches have not been explicated.

METHODS

A synthesis and application of Rubin's Causal Model is applied to the context of headache causes. From this application, the conditions necessary to infer that 1 event (trigger) causes another (headache) are outlined using basic assumptions and examples from relevant literature.

RESULTS

Although many conditions must be satisfied for a causal attribution, 3 basic assumptions are identified for determining causality in headache triggers: (1) constancy of the sufferer, (2) constancy of the trigger effect, and (3) constancy of the trigger presentation. A valid evaluation of a potential trigger's effect can only be undertaken once these 3 basic assumptions are satisfied during formal or informal studies of headache triggers.

CONCLUSIONS

Evaluating these assumptions is extremely difficult or infeasible in clinical practice, and satisfying them during natural experimentation is unlikely. Researchers, practitioners, and headache sufferers are encouraged to avoid natural experimentation to determine the causal effects of headache triggers. Instead, formal experimental designs or retrospective diary studies using advanced statistical modeling techniques provide the best approaches to satisfy the required assumptions and inform causal statements about headache triggers.

Triggers of migraine and tension-type headache in China: a clinic-based survey

BACKGROUND AND PURPOSE

Identification of the trigger factors of headache could be an important aspect of preventive management, but the characteristics of primary headache triggers in China are unknown. This study was performed to estimate the frequencies of the putative headache triggers, which are endorsed by patients with migraine and tension-type headache (TTH).

METHODS

From July 2011 to December 2011, a cross-sectional survey was conducted in the neurological clinic of a tertiary care hospital in Chongqing. All consecutive patients with the chief complaint of headache were interviewed by a board-certified headache specialist. The diagnoses were made according to International Classification of Headache Disorders - 2nd edition. Patients with migraine and TTH were recruited.

RESULTS

The number of investigated patients was 1219, of whom 394 were migraine and 344 were TTH; and 80.2% migraineurs and 67.4% TTH patients reported trigger factors. The most common triggers for both migraine and TTH were sleep disturbance, negative affect and sunlight. Menstrual cycle (OR 3.6, 95%CI 1.2, 11.2), change of the weather (OR 3.1, 95%CI 1.9, 4.8), noise (OR 2.2, 95%CI 1.1, 4.4) and alcohol (OR 1.8, 95%CI 0.7, 1.8) were more associated with migraineurs. Negative affect was more associated with TTH (OR 2.0, 95%CI 1.3, 2.9).

CONCLUSIONS

Trigger factors were frequent among both migraine and TTH patients. Avoidance of all headache triggers is impractical. Learning to cope with triggers is important to headache prevention.

Panic disorder and migraine: comorbidity, mechanisms, and clinical implications

A growing body of literature suggests that comorbid anxiety disorders are more common and more prognostically relevant among migraine sufferers than comorbid depression. Panic disorder (PD) appears to be more strongly associated with migraine than most other anxiety disorders. PD and migraine are both chronic diseases with episodic manifestations, involving significant functional impairment and shared symptoms during attacks, interictal anxiety concerning future attacks, and an absence of identifiable secondary pathology. A meta-analysis of high-quality epidemiologic study data from 1990 to 2012 indicates that the odds of PD are 3.76 times greater among individuals with migraine than those without. This association remains significant even after controlling for demographic variables and comorbid depression. Other less-rigorous community and clinical studies confirm these findings. The highest rates of PD are found among migraine with aura patients and those presenting to specialty clinics. Presence of PD is associated with greater negative impact of migraine, including more frequent attacks, increased disability, and risk for chronification and medication overuse. The mechanisms underlying this common comorbidity are poorly understood, but both pathophysiological (eg, serotonergic dysfunction, hormonal influences, dysregulation of the hypothalamic-pituitary-adrenal axis) and psychological (eg, interoceptive conditioning, fear of pain, anxiety sensitivity, avoidance behavior) factors are implicated. Means of assessing comorbid PD among treatment-seeking migraineurs are reviewed, including verbal screening for core PD symptoms, ruling out medical conditions with panic-like features, and administering validated self-report measures. Finally, evidence-based strategies for both pharmacologic and behavioral management are outlined. The first-line migraine prophylactics are not indicated for PD, and the selective serotonin re-uptake inhibitors used to treat PD are not efficacious for migraine; thus, separate agents are often required to address each condition. Core components of behavioral treatments for PD are reviewed, and their integration into clinical headache practice is discussed.

Clinical features of headache associated with mobile phone use: a cross-sectional study in university students

BACKGROUND

Headache has been reported to be associated with mobile phone (MP) use in some individuals. The causal relationship between headache associated with MP use (HAMP) and MP use is currently undetermined. Identifying the clinical features of HAMP may help in clarifying the pathophysiology of HAMP and in managing symptoms of individuals with HAMP. The aim of the present study is to describe the clinical features of HAMP.

METHODS

A 14-item questionnaire investigating MP use and headache was administered to 247 medical students at Hallym University, Korea. Individual telephone interviews were subsequently conducted with those participants who reported HAMP more than 10 times during the last 1 year on the clinical features of HAMP. We defined HAMP as a headache attack during MP use or within 1 hour after MP use.

RESULTS

In total, 214 (86.6%) students completed and returned the questionnaire. Forty (18.9%) students experienced HAMP more than 10 times during the last 1 year in the questionnaire survey. In subsequent telephone interviews, 37 (97.4%) interviewed participants reported that HAMP was triggered by prolonged MP use. HAMP was usually dull or pressing in quality (30 of 38, 79.0%), localised ipsilateral to the side of MP use (32 of 38, 84.2%), and associated with a burning sensation (24 of 38, 63.2%).

CONCLUSION

We found that HAMP usually showed stereotyped clinical features including mild intensity, a dull or pressing quality, localisation ipsilateral to the side of MP use, provocation by prolonged MP use and often accompanied by a burning sensation.

Behavioral management of migraine headache triggers: learning to cope with triggers

The literature on migraine triggers is reviewed, including the most common triggers, interactions between triggers, the research evidence related to the capacity of self-reported triggers to precipitate headaches, and the neurobiologic pathways by which triggers induce migraine attacks. An argument is developed against the standard advice to avoid migraine triggers as the best way of preventing attacks, based on conceptual and practical criticisms, and consideration of cognate literatures on chronic pain, stress, and anxiety. A small number of studies suggest that exposure to headache triggers has the same effect as exposure to anxiety-eliciting stimuli, with short exposure associated with increased pain response and prolonged exposure associated with decreased pain response. On the basis of this literature, "learning to cope with triggers" is advocated, where controlled exposure and approach/confront strategies are used to manage migraine triggers, except in cases where such an approach would probably be inappropriate.