Comparison of somatosensory cortex excitability between migraine and “strict-criteria” tension-type headache: a magnetoencephalographic study

Characteristic oscillatory brain networks for predicting patients with chronic migraine

To determine specific resting-state network patterns underlying alterations in chronic migraine, we employed oscillatory connectivity and machine learning techniques to distinguish patients with chronic migraine from healthy controls and patients with other pain disorders. This cross-sectional study included 350 participants (70 healthy controls, 100 patients with chronic migraine, 40 patients with chronic migraine with comorbid fibromyalgia, 35 patients with fibromyalgia, 30 patients with chronic tension-type headache, and 75 patients with episodic migraine). We collected resting-state magnetoencephalographic data for analysis. Source-based oscillatory connectivity within each network, including the pain-related network, default mode network, sensorimotor network, visual network, and insula to default mode network, was examined to determine intrinsic connectivity across a frequency range of 1-40 Hz. Features were extracted to establish and validate classification models constructed using machine learning algorithms. The findings indicated that oscillatory connectivity revealed brain network abnormalities in patients with chronic migraine compared with healthy controls, and that oscillatory connectivity exhibited distinct patterns between various pain disorders. After the incorporation of network features, the best classification model demonstrated excellent performance in distinguishing patients with chronic migraine from healthy controls, achieving high accuracy on both training and testing datasets (accuracy > 92.6% and area under the curve > 0.93). Moreover, in validation tests, classification models exhibited high accuracy in discriminating patients with chronic migraine from all other groups of patients (accuracy > 75.7% and area under the curve > 0.8). In conclusion, oscillatory synchrony within the pain-related network and default mode network corresponded to altered neurophysiological processes in patients with chronic migraine. Thus, these networks can serve as pivotal signatures in the model for identifying patients with chronic migraine, providing reliable and generalisable results. This approach may facilitate the objective and individualised diagnosis of migraine.

Visual Aura in Non-Migraine Headaches: A Population Study

BACKGROUND

Visual aura (VA) occurs mostly in migraine with aura (MA), but some case studies have reported aura in non-migraine headaches. Thus, information of VA in non-migraine headaches is scarce. Aim of this study was to investigate the prevalence and impact of VA in non-migraine headache and compare it with that of migraine headache.

METHODS

This study was a nationwide population-based study. We used an internet-based headache diagnosis questionnaire to diagnose headache, and various modules to evaluate clinical features and comorbidities of participants with headache. We defined migraine headache as migraine and probable migraine (PM), whereas non-migraine headache was defined as a headache but not migraine or PM. VA was defined as a self-reporting VA rating scale score ≥ 3.

RESULTS

Of the 3,030 participants, 1,431 (47.2%) and 507 (16.7%) had non-migraine headache and migraine headache, respectively. VA prevalence was much lower in the non-migraine headache group than in the migraine headache group (14.5% [207/1,431] vs. 26.0% [132/507], P < 0.001). In subjects with non-migraine headache, those with VA had a markedly higher number of headache days per 30 days (median [25th-75th percentiles]: 2.0 [1.0-5.0] vs. 2.0 [1.0-3.0], P < 0.001), and headache-related disability (6.0 [3.0-16.0] vs. 2.0 [0.0-7.0], P < 0.001) than those without VA. VA prevalence did not differ significantly according to age and sex.

CONCLUSION

Non-migraine headache with VA patients had more severe symptoms than those without VA. These findings may improve the understanding of VA and the management of individuals with non-migraine headache.

Intrinsic Brain Functional Activity Abnormalities in Episodic Tension-Type Headache

Objective

The neurobiological basis of episodic tension-type headache (ETTH) remains largely unclear. The aim of the present study was to explore intrinsic brain functional activity alterations in ETTH.

Methods

Resting-state functional magnetic resonance imaging (rs-fMRI) data were collected from 32 patients with ETTH and 32 age- and gender-matched healthy controls (HCs). Differences in intrinsic brain functional activity between patients with ETTH and HCs were analyzed utilizing the fractional amplitude of low-frequency fluctuation (fALFF) approach. Correlation analyses were performed to examine the relationship between fALFF alterations and clinical characteristics.

Results

Compared to HCs, patients with ETTH exhibited increased fALFF in the right posterior insula and anterior insula and decreased fALFF in the posterior cingulate cortex. Moreover, the fALFF in the right anterior insula was negatively correlated with attack frequency in ETTH.

Conclusions

This study highlights alterations in the intrinsic brain functional activity in the insula and posterior cingulate cortex in ETTH that can help us understand its neurobiological underpinnings.

Migraine Pathophysiology Revisited: Proposal of a New Molecular Theory of Migraine Pathophysiology and Headache Diagnostic Criteria

Various explanations for the pathophysiology of migraines have been proposed; however, none of these provide a complete explanation. The author critically reviews previous theories and proposes a new molecular theory of migraine pathophysiology. The diagnosis of primary headaches is generally based on clinical histories and symptoms only because there is no reliable diagnostic examination. The author proposes a new classification system and set of diagnostic criteria for headaches based on molecular markers.

Resting-state magnetoencephalographic oscillatory connectivity to identify patients with chronic migraine using machine learning

To identify and validate the neural signatures of resting-state oscillatory connectivity for chronic migraine (CM), we used machine learning techniques to classify patients with CM from healthy controls (HC) and patients with other pain disorders. The cross-sectional study obtained resting-state magnetoencephalographic data from 240 participants (70 HC, 100 CM, 35 episodic migraine [EM], and 35 fibromyalgia [FM]). Source-based oscillatory connectivity of relevant cortical regions was calculated to determine intrinsic connectivity at 1–40 Hz. A classification model that employed a support vector machine was developed using the magnetoencephalographic data to assess the reliability and generalizability of CM identification. In the findings, the discriminative features that differentiate CM from HC were principally observed from the functional interactions between salience, sensorimotor, and part of the default mode networks. The classification model with these features exhibited excellent performance in distinguishing patients with CM from HC (accuracy ≥ 86.8%, area under the curve (AUC) ≥ 0.9) and from those with EM (accuracy: 94.5%, AUC: 0.96). The model also achieved high performance (accuracy: 89.1%, AUC: 0.91) in classifying CM from other pain disorders (FM in this study). These resting-state magnetoencephalographic electrophysiological features yield oscillatory connectivity to identify patients with CM from those with a different type of migraine and pain disorder, with adequate reliability and generalizability.

Resting-state occipital alpha power is associated with treatment outcome in patients with chronic migraine

ABSTRACT

Preventive treatment is crucial for patients with chronic migraine (CM). This study explored the association between resting-state cortical oscillations and 3-month treatment outcome in patients with CM. Treatment-naïve patients with CM were recruited with their demographic data, psychosocial data, and headache profiles as well as the healthy controls (HCs). Resting-state cortical activities were recorded using an electroencephalogram and analysed using source-based and electrode-based spectral power method. The regions of interest were the bilateral primary somatosensory (S1) and visual (V1) cortices. After 3-month treatment with flunarizine, patients with CM were categorized into responders and nonresponders. Demographic, clinical, and electroencephalogram data from 72 patients with CM and 50 HCs were analysed. Elevated anxiety, depression, and stress were observed in patients with CM. Theta power in bilateral S1 and alpha and gamma powers in the right S1 increased in patients with CM. Nonresponders (n = 34) exhibited larger alpha powers in bilateral V1 than those in responders (n = 38). Alpha powers also exhibited significant correlations with changes of monthly headache days. Notably, in responders and nonresponders, occipital alpha powers did not differ at baseline and in the third month. In conclusion, patients with CM who were not responsive to preventive treatment were associated with augmented resting-state occipital alpha activity. Moreover, changes in migraine attack frequency were associated with baseline occipital alpha power. However, the prognostic feature of visual alpha oscillation seems to be inherent because it is not altered by flunarizine treatment. These findings may be useful for developing personalised migraine treatment plans.

Dynamic brainstem and somatosensory cortical excitability during migraine cycles

Abstract

Background

Migraine has complex pathophysiological characteristics and episodic attacks. To decipher the cyclic neurophysiological features of migraine attacks, in this study, we compared neuronal excitability in the brainstem and primary somatosensory (S1) region between migraine phases for 30 consecutive days in two patients with episodic migraine.

Methods

Both patients underwent EEG recording of event-related potentials with the somatosensory and paired-pulse paradigms for 30 consecutive days. The migraine cycle was divided into the following phases: 24–48 h before headache onset (Pre2), within 24 h before headache onset (Pre1), during the migraine attack (Ictal), within 24 h after headache offset (Post1), and the interval of ˃48 h between the last and next headache phase (Interictal). The normalised current intensity in the brainstem and S1 and gating ratio in the S1 were recorded and examined.

Results

Six migraine cycles (three for each patient) were analysed. In both patients, the somatosensory excitability in the brainstem (peaking at 12–14 ms after stimulation) and S1 (peaking at 18–19 ms after stimulation) peaked in the Pre1 phase. The S1 inhibitory capability was higher in the Ictal phase than in the Pre1 phase.

Conclusion

This study demonstrates that migraine is a cyclic excitatory disorder and that the neural substrates involved include the somatosensory system, starting in the brainstem and spanning subsequently to the S1 before the migraine occurs. Further investigations with larger sample sizes are warranted.

Psychophysical testing in chronic migraine and chronic tension type headache: An observational study

BACKGROUND

Clinical presentation is the key to the diagnosis of patients with migraine and tension-type headache, but features may overlap when both become chronic. Psychophysical parameters may distinguish both conditions. We aimed to compare psychophysical aspects of patients with chronic migraine, chronic tension-type headache and headache-free controls, and to determine whether these can predict headache frequency.

METHODS

An examiner blinded to the diagnosis assessed 100 participants (chronic migraine (n = 38), chronic tension-type headache (n = 31) and controls (n = 31)). Assessed variables included painful area, pressure pain thresholds, temporal summation, cervical range of motion, neck posture, headache and neck impact, quality of life, and kinesiophobia. Comparison between groups was performed with one-way ANOVA and multiple linear regression was used to assess the headache frequency predictors.

RESULTS

We found differences of both headache groups compared to controls (p < 0.01), but not between headache groups. Neck disability was a significant predictor of headache frequency for chronic tension-type headache (adjusted R² = 0.14; β = 0.43; p = 0.03) and chronic migraine (adjusted R² = 0.18; β = 0.51; p < 0.01).

CONCLUSIONS

Chronic tension-type headache and chronic migraine showed similar psychophysical results, but were significantly worse when compared to controls. The psychophysical examination did not discriminate between headache types. The variable best explaining headache frequency for both headache types was neck disability.

Tension-type headache

Tension-type headache (TTH) is the most prevalent neurological disorder worldwide and is characterized by recurrent headaches of mild to moderate intensity, bilateral location, pressing or tightening quality, and no aggravation by routine physical activity. Diagnosis is based on headache history and the exclusion of alternative diagnoses, with clinical criteria provided by the International Classification of Headache Disorders, third edition. Although the biological underpinnings remain unresolved, it seems likely that peripheral mechanisms are responsible for the genesis of pain in TTH, whereas central sensitization may be involved in transformation from episodic to chronic TTH. Pharmacological therapy is the mainstay of clinical management and can be divided into acute and preventive treatments. Simple analgesics have evidence-based effectiveness and are widely regarded as first-line medications for the acute treatment of TTH. Preventive treatment should be considered in individuals with frequent episodic and chronic TTH, and if simple analgesics are ineffective, poorly tolerated or contraindicated. Recommended preventive treatments include amitriptyline, venlafaxine and mirtazapine, as well as some selected non-pharmacological therapies. Despite the widespread prevalence and associated disability of TTH, little progress has been made since the early 2000s owing to a lack of attention and resource allocation by scientists, funding bodies and the pharmaceutical industry.

Somatosensory Gating Responses Are Associated with Prognosis in Patients with Migraine

Sensory gating, a habituation-related but more basic protective mechanism against brain sensory overload, is altered in patients with migraine and linked to headache severity. This study investigated whether somatosensory (SI) gating responses determined 3-months treatment outcomes in patients with episodic migraine (EM) and chronic migraine (CM). A 306-channel magnetoencephalography (MEG) with paired-pulse stimulation paradigm was used to record their neuromagnetic responses. To calculate the peak amplitude and latency and compute the gating ratios (second vs. first amplitude), the first and second responses to the paired stimuli from the primary somatosensory cortex were obtained. All patients were assigned to subgroups labeled good or poor according to their headache frequency at baseline compared with at the third month of treatment. The gating ratio in the CM group (n = 37) was significantly different between those identified as good and poor (p = 0.009). In the EM group (n = 30), the latency in the second response differed by treatment outcomes (p = 0.007). In the receiver operating characteristic analysis, the areas under the curve for the CM and EM groups were 0.737 and 0.761, respectively. Somatosensory gating responses were associated with treatment outcomes in patients with migraine; future studies with large patient samples are warranted.

Brain Excitability in Tension-Type Headache: a Separate Entity from Migraine?

PURPOSE OF REVIEW

Tension-type headache is often regarded as the "normal" headache due to its high prevalence and mild disability in contrast with migraine. Clinically, both headaches are common comorbidities to each other. To date there has been many studies linked migraine to a brain excitability disorder. This review summarized earlier studies on brain excitability of TTH and discuss if TTH is a separate clinical entity from migraine as suggested by the diagnostic criteria.

RECENT FINDINGS

A recent magnetoencephalographic study from our group enrolled patients with "strict-criteria" TTH (i.e., absence of any migraine characteristics and associated symptoms) to compare the somatosensory excitability with patients with migraine and controls. This study provided evidence that TTH and migraine differ in excitability profiles and the measurement of preactivation excitability was able to discriminate TTH from migraine. Earlier studies on brain excitability of TTH yielded negative findings or a common change shared with migraine. Future studies using strict diagnostic criteria to avoid the unwanted interference from migraine comorbidity may help decipher the "true" pathophysiology of TTH, which may pave the way to a TTH-specific brain signature and treatment.

Neuromagnetic Amygdala Response to Pain-Related Fear as a Brain Signature of Fibromyalgia

INTRODUCTION

Fibromyalgia (FM) is a chronic pain condition characterized by impaired emotional regulation. This study explored the brain response to pain-related fear as a potential brain signature of FM.

METHODS

We used a conditioned fear task and magnetoencephalography to record pain-related fear responses in patients with FM. Two blocks of 30 fear responses were collected to compute the response strength in the first block and the strength difference between the first and second blocks (fear habituation). These measurements were investigated for their clinical relevance and compared with measurements obtained from healthy controls and patients with chronic migraine (CM), a different chronic pain condition often comorbid with FM.

RESULTS

Pain-related fear clearly activated the bilateral amygdala and anterior insula in patients with FM (n = 52), patients with CM (n = 50), and the controls (n = 30); the response strength in the first block was consistent across groups. However, fear habituation in the right amygdala decreased in the FM group (vs. CM and control groups, both p ≤ 0.001, no difference between CM and control groups). At the 3-month follow-up, the patients with FM reporting < 30% improvement in pain severity (n = 15) after pregabalin treatment exhibited lower fear habituation in the left amygdala at baseline (vs. ≥ 30% improvement, n = 22, p = 0.019). Receiver operating characteristic analysis confirmed that amygdala fear habituation is a suitable predictor of diagnosis and treatment outcomes of FM (area under the curve > 0.7).

CONCLUSIONS

Amygdala activation to pain-related fear is maladaptive and linked to treatment outcomes in patients with FM. Because the aberrant amygdala response was not observed in the CM group, this response is a potential brain signature of FM.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier, NCT02747940.

Individual pain sensitivity is associated with resting-state cortical activities in healthy individuals but not in patients with migraine: a magnetoencephalography study

Background

Pain sensitivity may determine the risk, severity, prognosis, and efficacy of treatment of clinical pain. Magnetic resonance imaging studies have linked thermal pain sensitivity to changes in brain structure. However, the neural correlates of mechanical pain sensitivity remain to be clarified through investigation of direct neural activities on the resting-state cortical oscillation and synchrony.

Methods

We recorded the resting-state magnetoencephalographic (MEG) activities of 27 healthy individuals and 30 patients with episodic migraine (EM) and analyzed the source-based oscillatory powers and functional connectivity at 2 to 59 Hz in pain-related cortical regions, which are the bilateral anterior cingulate cortex (ACC), medial orbitofrontal (MOF) cortex, lateral orbitofrontal (LOF) cortex, insula cortex, primary somatosensory cortex (SI), primary motor cortex (MI), and posterior cingulate cortex (PCC). The mechanical punctate pain threshold (MPPT) was obtained at the supraorbital area (the first branch of the trigeminal nerve dermatome, V1) and the forearm (the first thoracic nerve dermatome, T1) and further correlated with MEG measures.

Results

The MPPT is inversely correlated with the resting-state relative powers of gamma oscillation in healthy individuals (all corrected P < 0.05). Specifically, inverse correlation was noted between the MPPT at V1 and gamma powers in the bilateral insula (r = − 0.592 [left] and − 0.529 [right]), PCC (r = − 0.619 and − 0.541) and MI (r = − 0.497 and − 0.549) and between the MPPT at T1 and powers in the left PCC (r = − 0.561) and bilateral MI (r = − 0.509 and − 0.520). Furthermore, resting-state functional connectivity at the delta to beta bands, especially between frontal (MOF, ACC, LOF, and MI), parietal (PCC), and sensorimotor (bilateral SI and MI) regions, showed a positive correlation with the MPPT at V1 and T1 (all corrected P < 0.05). By contrast, in patients with EM, the MPPT was not associated with resting-state cortical activities.

Conclusions

Pain sensitivity in healthy individuals is associated with the resting-state gamma oscillation and functional connectivity in pain-related cortical regions. Further studies must be conducted in a large population to confirm whether resting-state cortical activities can be an objective measurement of pain sensitivity in individuals without clinical pain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-020-01200-8.

Misperception of Visual Verticality in Patients with Primary Headache Disorders: A Systematic Review with Meta-Analysis

Migraine and tension-type headache (TTH) are the two most prevalent primary headache disorders (PHDs) that may involve visual and vestibular impairments, neck pain, and postural unsteadiness. The perception of visual verticality (VV) has been studied in patients diagnosed with PHD to assess balance disorders showing varying findings. Our study aimed to assess the VV perception in patients diagnosed with PHD in comparison to healthy controls. A systematic review with meta-analysis was carried out in PubMed MEDLINE, Scopus, WOS, CINAHL, and SciELO. The Cohen standardized mean difference (SMD) was used to estimate the differences between exposed and healthy controls. Seven studies with 816 participants were included. The quality of included studies, according to the Newcastle–Ottawa Scale (NOS), was moderate (mean score of 5.2). Patients diagnosed with PHD showed a moderate misperception of VV as assessed with the subjective visual vertical (SVV) test (SMD = 0.530; 95% CI = 0.225, 0.836; p < 0.001). Specifically, a misperception of the SVV was found in patients with migraine (SMD = 0.369; 95% CI = 0.1, 0.638; p = 0.007) and with TTH (SMD = 1.122; 95% CI = 0.540, 1.704; p < 0.001). This review shows a misperception of VV in patients with migraine and TTH when assessed with the SVV test, being higher in patients with TTH, although the THH sample size was low.

Risks of tinnitus, sensorineural hearing impairment, and sudden deafness in patients with non-migraine headache

Tinnitus and hearing impairment are prevalent among headache patients. This study aims to investigate the risk of tinnitus, sensorineural hearing impairment, and sudden deafness in patients with non-migraine headache. Participants included 43 294 patients with non-migraine headache (non-migraine headache cohort) and 173 176 patients with no headache of any type (control cohort) frequency-matched with respect to 10-year age interval and sex from the Longitudinal Health Insurance Database 2005 of the Taiwan National Health Insurance Research Database. The mean age of the non-migraine headache cohort was 28.4 ± 14.9 years, and 58.5% of this cohort was male. The incidence rates of tinnitus, sensorineural hearing impairment, and sudden deafness were compared between cohorts using the Kaplan–Meier method with the log-rank test. A Cox proportional hazard model was used to examine the association of tinnitus, sensorineural hearing impairment, and sudden deafness with non-migraine headache, with adjustment for all covariates. The combined risk of either tinnitus, sensorineural hearing impairment, or sudden deafness was higher in the non-migraine headache cohort than in the control cohort (adjusted odds ratio [aHR], 2.73; 95% confidence interval [95% CI], 2.62–2.84; p < 0.0001). Subgroup analysis showed that patients in the non-migraine headache cohort were at significantly higher risk of developing tinnitus (aHR, 3.05; 95% CI, 2.91–3.19; p < 0.0001), sensorineural hearing impairment (aHR, 1.89; 95% CI, 1.74–2.05; p < 0.0001), and sudden deafness (aHR, 2.14; 95% CI, 1.77–2.59; p < 0.0001) than were controls. In this population-based study, the risks of tinnitus, sensorineural hearing impairment, and sudden deafness were found to be significantly higher in patients with non-migraine headache than in those without headache.

Primary headaches during lifespan

Primary headaches are one of the most prevalent neurological disorders and can occur during a wide range of lifespan. Primary headaches, especially migraine, are cyclic disorders with a complex sequence of symptoms within every headache attack. There is no systematic review of whether these symptoms changes during lifespan. Indeed, the clinical presentation of migraine shows an age-dependent change with a significantly shorter duration of the attacks and occurrence of different paroxysmal symptoms, such as vomiting, abdominal pain or vertigo, in childhood and, in contrast, largely an absence of autonomic signs and a more often bilateral headache in the elderly. The age-dependent differences in the clinical presentation are less distinct in cluster headache and, especially, in tension-type headache. The differences in the clinical presentation are in agreement with the idea that the connectivity of hypothalamic areas with different brainstem areas, especially the central parasympathetic areas, is important for the clinical manifestation of migraine, as well as, the change during lifespan.