Neurophysiological and Clinical Outcomes in Episodic Migraine Without Aura: A Cross-Sectional Study

PURPOSE

The aim of this study was to assess differences between people with episodic migraine and healthy controls in some neurophysiological and clinical outcomes, which, in turn, may highlight the differences in sensory processing, especially in cortical excitability, pain processing, and executive function.

METHODS

A cross-sectional study was performed, including the following outcomes: pressure pain thresholds with algometry; resting motor threshold, short-interval intracortical inhibition, and intracortical facilitation with transcranial magnetic stimulation; and executive functions with the trail making test and the frontal assessment battery.

RESULTS

Thirty adults with migraine (36 ± 10 years) and 30 healthy controls (29 ± 14 years) were included in this study. Compared with the healthy controls, participants with migraine presented lower pressure pain thresholds values in all the assessed muscles ( P < 0.001), lower resting motor threshold (-10.5% of the stimulator output, 95% CI: -16.8 to -4.2, P = 0.001, Cohen d = 0.869) and higher short-interval intracortical inhibition motor-evoked potential's amplitude at 3 ms (0.25, 95% CI: 0.05 to 0.46, P = 0.015, Cohen d = 0.662), and worse performances both in trail making test (7.1, 95% CI: 0.9 to 13.4, P = 0.027, Cohen d = 0.594) and frontal assessment battery (-1.1, 95% CI: -1.7 to -0.5, P = 0.001, Cohen d = 0.915).

CONCLUSIONS

Participants with migraine presented significant differences in cortical excitability, executive functions, and pressure pain thresholds, compared with healthy controls.

Changes in brain connectivity linked to multisensory processing of pain modulation in migraine with acupuncture treatment

Migraine without aura (MWoA) is a major neurological disorder with unsatisfactory adherence to current medications. Acupuncture has emerged as a promising method for treating MWoA. However, the brain mechanism underlying acupuncture is yet unclear. The present study aimed to examine the effects of acupuncture in regulating brain connectivity of the key regions in pain modulation. In this study, MWoA patients were recruited and randomly assigned to 4 weeks of real or sham acupuncture. Resting-state functional magnetic resonance imaging (fMRI) data were collected before and after the treatment. A modern neuroimaging literature meta-analysis of 515 fMRI studies was conducted to identify pain modulation-related key regions as regions of interest (ROIs). Seed-to-voxel resting state-functional connectivity (rsFC) method and repeated-measures two-way analysis of variance were conducted to determine the interaction effects between the two groups and time (baseline and post-treatment). The changes in rsFC were evaluated between baseline and post-treatment in real and sham acupuncture groups, respectively. Clinical data at baseline and post-treatment were also recorded in order to determine between-group differences in clinical outcomes as well as correlations between rsFC changes and clinical effects. 40 subjects were involved in the final analysis. The current study demonstrated significant improvement in real acupuncture vs sham acupuncture on headache severity (monthly migraine days), headache impact (6-item Headache Impact Test), and health-related quality of life (Migraine-Specific Quality of Life Questionnaire). Five pain modulation-related key regions, including the right amygdala (AMYG), left insula (INS), left medial orbital superior frontal gyrus (PFCventmed), left middle occipital gyrus (MOG), and right middle cingulate cortex (MCC), were selected based on the meta-analysis on brain imaging studies. This study found that 1) after acupuncture treatment, migraine patients of the real acupuncture group showed significantly enhanced connectivity in the right AMYG/MCC-left MTG and the right MCC-right superior temporal gyrus (STG) compared to that of the sham acupuncture group; 2) negative correlations were established between clinical effects and increased rsFC in the right AMYG/MCC-left MTG; 3) baseline right AMYG-left MTG rsFC predicts monthly migraine days reduction after treatment. The current results suggested that acupuncture may concurrently regulate the rsFC of two pain modulation regions in the AMYG and MCC. MTG and STG may be the key nodes linked to multisensory processing of pain modulation in migraine with acupuncture treatment. These findings highlighted the potential of acupuncture for migraine management and the mechanisms underlying the modulation effects.

Acute sleep deprivation enhances susceptibility to the migraine substrate cortical spreading depolarization

BACKGROUND

Migraine is a common headache disorder, with cortical spreading depolarization (CSD) considered as the underlying electrophysiological event. CSD is a slowly propagating wave of neuronal and glial depolarization. Sleep disorders are well known risk factors for migraine chronification, and changes in wake-sleep pattern such as sleep deprivation are common migraine triggers. The underlying mechanisms are unknown. As a step towards developing an animal model to study this, we test whether sleep deprivation, a modifiable migraine trigger, enhances CSD susceptibility in rodent models.

METHODS

Acute sleep deprivation was achieved using the "gentle handling method", chosen to minimize stress and avoid confounding bias. Sleep deprivation was started with onset of light (diurnal lighting conditions), and assessment of CSD was performed at the end of a 6 h or 12 h sleep deprivation period. The effect of chronic sleep deprivation on CSD was assessed 6 weeks or 12 weeks after lesioning of the hypothalamic ventrolateral preoptic nucleus. All experiments were done in a blinded fashion with respect to sleep status. During 60 min of continuous topical KCl application, we assessed the total number of CSDs, the direct current shift amplitude and duration of the first CSD, the average and cumulative duration of all CSDs, propagation speed, and electrical CSD threshold.

RESULTS

Acute sleep deprivation of 6 h (n = 17) or 12 h (n = 11) duration significantly increased CSD frequency compared to controls (17 ± 4 and 18 ± 2, respectively, vs. 14 ± 2 CSDs/hour in controls; p = 0.003 for both), whereas other electrophysiological properties of CSD were unchanged. Acute total sleep deprivation over 12 h but not over 6 h reduced the electrical threshold of CSD compared to controls (p = 0.037 and p = 0.095, respectively). Chronic partial sleep deprivation in contrast did not affect CSD susceptibility in rats.

CONCLUSIONS

Acute but not chronic sleep deprivation enhances CSD susceptibility in rodents, possibly underlying its negative impact as a migraine trigger and exacerbating factor. Our findings underscore the importance of CSD as a therapeutic target in migraine and suggest that headache management should identify and treat associated sleep disorders.

Objective Diagnosis of Migraine without Aura with Migraine Vascular Index: A Novel Formula to Assess Vasomotor Reactivity

This pilot study was aimed at developing an objective method to diagnose migraine by measuring the difference in vasomotor reactivity between migraineurs and non-migraineurs. Thirty patients diagnosed with migraine without aura and 30 healthy patients were recruited. Vasomotor reactivity of all patients was then assessed by measuring the breath holding index (BHI), hyperventilation index and a novel formula, the migraine vascular index (MVI), of the middle cerebral artery using transcranial Doppler ultrasonography. Migraineurs were found to have significantly lower BHI and MVI values (p < 0.001). Logistic regression analysis revealed that MVI was a significant independent predictor of migraine (p = 0.007). The sensitivity and specificity of MVI in diagnosing migraine with a cutoff value of 1.035 were 86.7% and 86.7%, respectively. In conclusion, MVI measurement is a reliable method for objectively diagnosing migraine. Further research is needed to validate the usage of MVI for migraine diagnosis.

Altered lateral geniculate nucleus functional connectivity in migraine without aura: a resting-state functional MRI study

OBJECTIVES

To investigate the structural and functional connectivity changes of lateral geniculate nucleus (LGN) and their relationships with clinical characteristics in patients without aura.

METHODS

Conventional MRI, 3D structure images and resting state functional MRI were performed in 30 migraine patients without aura (MwoA) and 22 healthy controls (HC). The lateral geniculate nucleus volumes and the functional connectivity (FC) of bilateral lateral geniculate nucleus were computed and compared between groups.

RESULTS

The lateral geniculate nucleus volumes in patient groups did not differ from the controls. The brain regions with increased FC of the left LGN mainly located in the left cerebellum and right lingual gyrus in MwoA compared with HC. The increased FC of right LGN located in left inferior frontal gyrus in MwoA compared with HC. The correlation analysis showed a positive correlation between VLSQ-8 score and the increased FC of left cerebellum and right lingual gyrus.

CONCLUSIONS

Photophobia in MwoA could be mediated by abnormal resting state functional connectivity in visual processing regions, the pain perception regulatory network and emotion regulation network. This result is valuable to further understanding about the clinical manifestation and pathogenesis of migraine.

Impaired intrinsic functional connectivity between the thalamus and visual cortex in migraine without aura

BACKGROUND

Resting-state functional magnetic resonance imaging (fMRI) has confirmed disrupted visual network connectivity in migraine without aura (MwoA). The thalamus plays a pivotal role in a number of pain conditions, including migraine. However, the significance of altered thalamo-visual functional connectivity (FC) in migraine remains unknown. The goal of this study was to explore thalamo-visual FC integrity in patients with MwoA and investigate its clinical significance.

METHODS

Resting-state fMRI data were acquired from 33 patients with MwoA and 22 well-matched healthy controls. After identifying the visual network by independent component analysis, we compared neural activation in the visual network and thalamo-visual FC and assessed whether these changes were linked to clinical characteristics. We used voxel-based morphometry to determine whether functional differences were dependent on structural differences.

RESULTS

The visual network exhibited significant differences in regions (bilateral cunei, right lingual gyrus and left calcarine sulcus) by inter-group comparison. The patients with MwoA showed significantly increased FC between the left thalami and bilateral cunei and between the right thalamus and the contralateral calcarine sulcus and right cuneus. Furthermore, the neural activation of the left calcarine sulcus was positively correlated with visual analogue scale scores (r = 0.319, p = 0.043), and enhanced FC between the left thalamus and right cuneus in migraine patients was negatively correlated with Generalized Anxiety Disorder scores (r = - 0.617, p = 0.005).

CONCLUSION

Our data suggest that migraine distress is exacerbated by aberrant feedback projections to the visual network, playing a crucial role in migraine physiological mechanisms. The current study provides further insights into the complex scenario of migraine mechanisms.

Migraine without Aura and Subclinical Atherosclerosis in Young Females: Is Gut Microbiota to Blame?

Background and Objectives: Migraine with aura (MA) could be considered a risk factor for developing atherosclerosis and cardio-vascular events. However, less is known about the relation between migraine without aura (MWA) and atherosclerosis. Our study aimed to assess whether young female migraineurs, with alterations of gut microbiota could associate early atherosclerosis. Materials and Methods: We conducted an exploratory cross-sectional, pilot study concerning 105 consecutive young females having MWA, with recent normal brain scans, that were free of cardio-vascular risk factors, non-smokers, not on oral contraception, not pregnant, and without thyroid or parathyroid diseases, chronic organ failure, cancer, or on probiotic or antibiotic treatment. Consecutive to assessment of gut microbiota, patients were assigned to two groups: dysbiosis positive (n = 45) and dysbiosis negative (n = 60). All study participants underwent clinical examinations with an assessment of migraine severity, body mass index and carotid intima-media thickness (CIMT), as well as laboratory workups. Statistical analysis was performed using a chi-squared test (χ2), a two-tailed t-test and a nonparametric Spearman's correlation test. Results: The dysbiosis positive migraineurs showed a significant increase in CIMT along with several anthropometrical, biological and clinical particularities. Significant positive correlations between dysbiosis and CIMT, glycosylated hemoglobin, migraine severity and duration, tumor necrosis factor-alpha, and body mass index were found. Conclusions: Young female migraineurs with significant alterations of gut microbiota experienced early signs of atherosclerosis and displayed severe migraine disability, as well as multiple biological and clinical particularities.

Differences in treatment response between migraine with aura and migraine without aura: lessons from clinical practice and RCTs

Migraine is a major public health problem afflicting approximately 10% of the general population and is a leading cause of disability worldwide, yet our understanding of the basis mechanisms of migraine remains incomplete. About a third of migraine patients have attacks with aura, consisting of transient neurological symptoms that precede or accompany headache, or occur without headache. For patients, aura symptoms are alarming and may be transiently disabling. For clinicians and scientists, aura represents an intriguing neurophysiological event that may provide important insight into basic mechanisms of migraine. Several observations point toward important differences between migraine with and without aura. Compared with migraine without aura, migraine with aura has different heritability, greater association with different conditions including stroke, different alterations of brain structure and function as revealed by imaging studies. A number of studies also indicate that migraine with aura may respond differently to acute and preventive therapies as compared to migraine without aura. The purpose of this review is to provide an overview of these differences in treatment responses, and to discuss the possibility of different therapeutic strategies for migraine with vs. without aura.

Relating excitatory and inhibitory neurochemicals to visual perception: A magnetic resonance study of occipital cortex between migraine events

Certain perceptual measures have been proposed as indirect assays of brain neurochemical status in people with migraine. One such measure is binocular rivalry, however, previous studies have not measured rivalry characteristics and brain neurochemistry together in people with migraine. This study compared spectroscopy-measured levels of GABA and Glx (glutamine and glutamate complex) in visual cortex between 16 people with migraine and 16 non-headache controls, and assessed whether the concentration of these neurochemicals explains, at least partially, inter-individual variability in binocular rivalry perceptual measures. Mean Glx level was significantly reduced in migraineurs relative to controls, whereas mean occipital GABA levels were similar between groups. Neither GABA levels, nor Glx levels correlated with rivalry percept duration. Our results thus suggest that the previously suggested relationship between rivalry percept duration and GABAergic inhibitory neurotransmitter concentration in visual cortex is not strong enough to enable rivalry percept duration to be reliably assumed to be a surrogate for GABA concentration, at least in the context of healthy individuals and those that experience migraine.

The altered Granger causality connection among pain-related brain networks in migraine

Numerous fMRI studies have confirmed functional abnormalities in resting-state brain networks in migraine patients. However, few studies focusing on causal relationships of pain-related brain networks in migraine have been conducted. This study aims to explore the difference of Granger causality connection among pain-related brain networks in migraine without aura (MWoA) patients.Twenty two MWoA patients and 17 matched healthy subjects were recruited to undergo resting-state fMRI scanning. Independent component analysis was used to extract pain-related brain networks, and Granger causality analysis to characterize the difference of Granger causality connection among pain-related brain networks was employed.Seven pain-related brain networks were identified, and MwoA patients showed more complex Granger causality connections in comparison with healthy subjects. Two-sample t test results displayed that there was the significant difference between right-frontoparietal network (RFPN) and executive control network (ECN).This study indicates that the specific intrinsic brain Granger causality connectivity among pain-related networks in MwoA patients are affected after long-term migraine attacks.

Clinical characteristics of menstrually related and non-menstrual migraine

Migraine attacks increase during the perimenstrual period in approximately half of female migraineurs. There are differences in the pathogenesis and clinical features of menstrually related and non-menstrual migraine attacks. The objective of this study was to compare the characteristics of migraine in patients with menstrually related and non-menstrual migraine, and to investigate the differences between premenstrual, menstrual, and late-menstrual migraine attacks. Three-hundred and thirty-two women with migraine without aura were evaluated using questionnaires and diaries to determine the characteristics of headache, preceding and accompanying symptoms, and the relation of migraine attacks and menstruation. One-hundred and sixty-three women had menstrually related migraine without aura (49.1%). Duration of disease and duration of headache were longer (p = 0.002 and p < 0.001, respectively), and nausea, vomiting, phonophobia, and aggravation of headache with physical activity were more frequent in patients with menstrually related migraine (p = 0.005, p = 0.006, p < 0.001 and p = 0.006, respectively). Premonitory symptoms and allodynia were observed more frequently in the menstrually related migraine group (p = 0.012 and p = 0.004, respectively). Perimenstrual migraine attacks occurred premenstrually (days -2 and -1) in 46 patients (25.3%), menstrually (days 1 to 3) in 90 patients (49.4%), and late menstrually (days 4 to 7) in 19 patients (10.4%). Our results showed that the duration of headache was longer and accompanying symptoms were more frequent and diverse in patients with menstrually related migraine without aura, suggesting that these findings may reflect the increase in excitability or susceptibility of the brain in these patients.

Acupuncture modulates the abnormal brainstem activity in migraine without aura patients

Migraine is a common neurological disease with a high prevalence and unsatisfactory treatment options. The specific pathophysiological mechanisms of migraine remain unclear, which restricts the development of effective treatments for this prevalent disorder. The aims of this study were to 1) compare the spontaneous brain activity differences between Migraine without Aura (MwoA) patients and healthy controls (HCs), using amplitude of low-frequency fluctuations (ALFF) calculation method, and 2) explore how an effective treatment (verum acupuncture) could modulate the ALFF of MwoA patients. One hundred MwoA patients and forty-six matched HCs were recruited. Patients were randomized to four weeks' verum acupuncture, sham acupuncture, and waiting list groups. Patients had resting state BOLD-fMRI scan before and after treatment, while HCs only had resting state BOLD-fMRI scan at baseline. Headache intensity, headache frequency, self-rating anxiety and self-rating depression were used for clinical efficacy evaluation. Compared with HCs, MwoA patients showed increased ALFF in posterior insula and putamen/caudate, and reduced ALFF in rostral ventromedial medulla (RVM)/trigeminocervical complex (TCC). After longitudinal verum acupuncture treatment, the decreased ALFF of the RVM/TCC was normalized in migraine patients. Verum acupuncture and sham acupuncture have different modulation effects on ALFF of RVM/TCC in migraine patients. Our results suggest that impairment of the homeostasis of the trigeminovascular nociceptive pathway is involved in the neural pathophysiology of migraines. Effective treatments, such as verum acupuncture, could help to restore this imbalance.

Aerobic Exercise and Plasma Beta Endorphin Levels in Patients with Migrainous Headache Without Aura

This study aims to evaluate the effects of plasma beta endorphin level and exercise on migrainous headache. Forty patients with migrainous headache without aura (MWOA), firstly exercised on a treadmill and afterwards were asked to continue an aerobic home exercise program for six weeks. On evaluation, basal plasma beta endorphin level was negatively correlated with total duration of attacks in the last month period ( P = 0.01). Exercise was found to have beneficial effects on all migraine parameters ( P < 0.0001) and to increase beta endorphin levels after the treadmill practice ( P < 0.0001) and after the home exercise program except four patients not regularly attended to the program ( P < 0.0001). Any of the changes in headache parameters was not correlated with the change in beta endorphin level. However, pre-exercise beta endorphin level was found to be negatively correlated with the changes in the number of attacks ( P < 0.05) and total duration of attacks ( P = 0.01) and also with the change in beta endorphin level due to exercise ( P < 0.0001). As a result, this study emphasizes the beneficial effect of exercise on migrainous headache, especially in patients with lower basal beta endorphin level.

Cognitive and Behavioural Effects of Migraine in Childhood and Adolescence

Since cognitive and behavioural characteristics of paediatric migraineurs have yet to be adequately defined, in this study we assessed the effect of migraine on the interictal functioning of children and adolescents by comparing the performance of two patient groups, 17 migraineurs with aura (MA) and 31 without aura (MoA) and by correlating the duration of the disorder, the frequency of attacks and interictal period with neuropsychological and behavioural findings. Both patient groups had cognitive performance within normal range except for a significant delay in the reaction time (RT) task. Both MA and MoA revealed a behavioural phenotype characterized by internalizing problems on Child Behaviour Check List (CBCL) scales. Slower RT to simple visual stimuli may be an early sign of a subclinical neuropsychological dysfunction, significantly correlated with the frequency of headache attacks and interictal period. The lack of a control group and other methodological limitations, such as patient selection bias and unadjusted P-value for multiple testing, make it difficult to give this finding a clearcut meaning. Further studies are needed on larger samples compared with a control group.

Interictal Executive Dysfunction in Migraineurs Without Aura: Relationship With Duration and Intensity of Attacks

Subjects with migraine are at increased risk of subcortical white matter lesions (WML). Reports of cognitive testing in adults with migraine have yielded inconsistent results. We performed a cross-sectional study to assess whether migraine without aura (MwA) is associated with impairment in executive functioning, a typical cognitive correlate of subcortical WML. Forty-five subjects with MwA and 90 controls, matched for age and education, underwent a cognitive battery of tests evaluating executive functions. The following migraine characteristics were collected: age at onset and length of migraine history, and frequency, duration and intensity of attacks. Subjects with MwA performed significantly lower than controls in tests evaluating complex, multifactorial executive functions. After multiple adjustments, the duration and intensity of migraine attacks significantly predicted cognitive disturbances. In the interictal phase of MwA there is evidence of mild executive dysfunction. The cumulative effects of repeated migraine attacks on prefronto-cerebellar loop probably account for our results.

Cognitive Function is not Impaired in People with a Long History of Migraine: A Blinded Study

Little is known about the long-term consequences of migraine for cognitive functioning. This study compared older migraine patients with matched controls on four measures of cognitive ability, in a blinded design. Migraine patients and case-matched controls were recruited from the database records of a pre-existing study of ageing. Data were available from four tests of cognitive ability: verbal/arithmetic problem solving, spatial problem solving, processing speed, and vocabulary. There were no significant differences between the mean scores of migraine and control groups on any of the four cognitive tests. In addition, there were no significant differences between migraine and control groups in the effect of age on any of the four tests. A long history of migraine does not compromise scores on the four cognitive tests used in this study. These tests are predictive of memory and executive functioning in cognitive ageing, but it remains possible that lower-level cognitive processes, particularly as assessed by visual tasks, may be vulnerable to migraine.

Inhibition of the Nociceptive R2 Blink Reflex after Supraorbital or Index Finger Stimulation is Normal in Migraine Without Aura Between Attacks

In order to explore possible interictal brainstem dysfunctions in migraine, we have studied the R2 component of the nociceptive specific blink reflex (nBR) after conditioning by supraorbital or index finger stimuli in 14 untreated migraine without aura patients (MO) between attacks and in 15 healthy volunteers. We determined the R2 recovery curve at increasing inter-stimulus intervals between 50 and 600 ms. The nBR was conditioned by a paired supraorbital stimulus and, in another session, by an ipsilateral electrical shock delivered to the index finger. The R2 nBR recovery curves were normal in MO patients for both the supraorbital and peripheral conditioning. These results do not favour persistent interictal sensitization in the spinal trigeminal sensory system. They also suggest that the control exerted by descending brainstem pathways on medullary R2 interneurones is normal in migraine between attacks.

Near infrared spectroscopy--investigations in neurovascular diseases

The purpose of this thesis was to explore and develop methods, where continuous wave near infrared spectroscopy (CW-NIRS) can be applied in different neurovascular diseases, in order to find biological markers that are useful in clinical neurology. To develop a new method to detect changes in cerebral blood flow (CBF), the first study investigated a multi-source detector separation configuration and indocyanine green (ICG) as a tracer to calculate a corrected blood flow index (BFI) value. The study showed no correlation between CBF changes measured by 133Xenon single photon emission computer tomography (133Xe-SPECT) and the corrected BFI value. It was concluded, that it was not possible to obtain reliable BFI data with the ICG CW-NIRS method. NIRS measurements of low frequency oscillations (LFOs) may be a reliable method to investigate vascular alterations in neurovascular diseases, but this requires an acceptable LFOs variation between hemispheres and over time in the healthy brain. The second study therefore investigated day-to-day and hemispheric variations in LFOs with NIRS. It was shown that NIRS might be useful in assessing LFOs between hemispheres, as well as interhemispheric phase and gain directly and over time. Migraine may be associated with persistent impairment of neurovascular coupling, but there is no experimental evidence to support this. The third study therefore investigated interictal neurovascular coupling during a mental task by a Stroop test in migraine without aura (MO) patients, which is the most common type of migraine. The study showed intact neurovascular coupling in the prefrontal cortex outside of attacks in patients with MO. The fourth study aimed to investigate possible changes in LFOs amplitude following nitric oxide (NO) donor infusion in familial hemiplegic migraine (FHM), which is a rare Mendelian subtype of migraine with aura. This study showed increased LFOs amplitude only in FHM patients with co-existing common type of migraine, but not in patients with pure FHM phenotype. This suggests that the sensitivity to NO resides within the common migraine phenotypes rather than the FHM phenotype. Stimulation of the sphenopalatine ganglion (SPG) may lead to parasympathetic outflow and cause pain in cluster headache (CH). The fifth study therefore investigated pain and autonomic symptoms in relation to high or low SPG frequency stimulation in chronic CH patients. Cortical changes in oxygenated hemoglobin (HbO) were also recorded with NIRS and showed a moderate HbO increase, which was most pronounced on the ipsilateral CH side following high frequency stimulation. A possible application of NIRS to assess cerebral vascular changes due to sympathetic activity was investigated in obstructive sleep apnoea (OSA) patients, who have increased sympathetic activity and risk of stroke. Following successful continuous positive airway pressure (CPAP) therapy, OSA patients decreased their LFOs amplitude, which was interpreted as a marker of decreased sympathetic activity in cortical vessels. Finally, a novel hybrid technique, combining NIRS and ultrasound, was tested to detect CBF changes after acetazolamide injection in healthy volunteers using a cerebral flow index (CFI). The study showed an increase in CFI, which correlated with CBF measured with 133Xe-SPECT at 15 min. but not 60 min. Further methodological and explorative clinical studies are needed to assess the feasibility of ultrasound-tagged NIRS in clinical neurology. In summary, the thesis presents several novel approaches, by which NIRS may be used in clinical neurology, and potentials of NIRS to investigate complex mechanisms in neurovascular diseases.

Autonomic impairment in patients with migraine

OBJECTIVE

Heart rate variability analysis of electrocardiogram is becoming an increasingly common method to non-invasively evaluate autonomic nervous function. The aim of the study was to investigate cardiac autonomic function in subjects with and without migraine by using 24-hour ambulatory electrocardiographic recordings.

PATIENTS AND METHODS

We investigated 27 subjects with migraine (10 with migraine with aura and 17 without aura) during headache free periods and 10 age-matched healthy control subjects. The migraine was diagnosed using the International Classification of Headache Disorders 2nd Edition criteria. Beck Depression and Beck Anxiety Inventory forms were completed by all subjects. Time and frequency-domain of HRV was analyzed for two periods: diurnal and nocturnal.

RESULTS

We found an increased frequency of anxiety and depressive symptoms in migraine patients, especially in migraine with aura group. The heart rate variability parameters SDNN, RMSSD, high frequency were decreased and low frequency was increased in migraine patients during night period compared with normal subjects, most affected were migraine with aura patients. During day period we found modification for SDNN, RMSSD and high frequency parameters only in migraine with aura group.

CONCLUSIONS

Reduced parasympathetic activity with sympathetic predominance was found in migraine patients during the night period, most affected being migraine with aura patients.

Elevated audiovisual temporal interaction in patients with migraine without aura

BACKGROUND

Photophobia and phonophobia are the most prominent symptoms in patients with migraine without aura. Hypersensitivity to visual stimuli can lead to greater hypersensitivity to auditory stimuli, which suggests that the interaction between visual and auditory stimuli may play an important role in the pathogenesis of migraine. However, audiovisual temporal interactions in migraine have not been well studied. Therefore, our aim was to examine auditory and visual interactions in migraine.

METHODS

In this study, visual, auditory, and audiovisual stimuli with different temporal intervals between the visual and auditory stimuli were randomly presented to the left or right hemispace. During this time, the participants were asked to respond promptly to target stimuli. We used cumulative distribution functions to analyze the response times as a measure of audiovisual integration.

RESULTS

Our results showed that audiovisual integration was significantly elevated in the migraineurs compared with the normal controls (p < 0.05); however, audiovisual suppression was weaker in the migraineurs compared with the normal controls (p < 0.05).

CONCLUSIONS

Our findings further objectively support the notion that migraineurs without aura are hypersensitive to external visual and auditory stimuli. Our study offers a new quantitative and objective method to evaluate hypersensitivity to audio-visual stimuli in patients with migraine.

Abnormal thalamic function in patients with vestibular migraine

OBJECTIVE

To investigate the functional response of neural pathways associated with vestibular stimulation in patients with vestibular migraine (VM).

METHODS

Twelve patients with VM underwent whole-brain blood oxygen level-dependent (BOLD) fMRI during ear irrigation with cold water. The functional response of neural pathways to this stimulation in patients with VM was compared with age- and sex-matched patients with migraine without aura and healthy controls. Secondary analyses explored associations between BOLD signal change and clinical features of migraine in patients.

RESULTS

We observed a robust cortical and subcortical pattern of BOLD signal change in response to ear irrigation across all participants. Patients with VM showed a significantly increased thalamic activation in comparison with both patients with migraine without aura and healthy controls. The magnitude of thalamic activation was positively correlated with the frequency of migraine attacks in patients with VM.

CONCLUSIONS

We provide novel evidence for abnormal thalamic functional response to vestibular stimulation in patients with VM. These functional abnormalities in central vestibular processing may contribute to VM pathophysiology.

Migraine generator network and spreading depression dynamics as neuromodulation targets in episodic migraine

Migraine is a common disabling headache disorder characterized by recurrent episodes sometimes preceded or accompanied by focal neurological symptoms called aura. The relation between two subtypes, migraine without aura (MWoA) and migraine with aura (MWA), is explored with the aim to identify targets for neuromodulation techniques. To this end, a dynamically regulated control system is schematically reduced to a network of the trigeminal nerve, which innervates the cranial circulation, an associated descending modulatory network of brainstem nuclei, and parasympathetic vasomotor efferents. This extends the idea of a migraine generator region in the brainstem to a larger network and is still simple and explicit enough to open up possibilities for mathematical modeling in the future. In this study, it is suggested that the migraine generator network (MGN) is driven and may therefore respond differently to different spatio-temporal noxious input in the migraine subtypes MWA and MWoA. The noxious input is caused by a cortical perturbation of homeostasis, known as spreading depression (SD). The MGN might even trigger SD in the first place by a failure in vasomotor control. As a consequence, migraine is considered as an inherently dynamical disease to which a linear course from upstream to downstream events would not do justice. Minimally invasive and noninvasive neuromodulation techniques are briefly reviewed and their rational is discussed in the context of the proposed mechanism.

Regional homogeneity abnormalities affected by depressive symptoms in migraine patients without aura: a resting state study

Background

Bidirectional relationship between migraine and depression suggests that there might be some etiological risk factors shared. However, few studies investigated resting state abnormalities affected by depressive symptoms in migraine patients without aura (MWoA).

Materials and Methods

According to their self-rating depression scale (SDS) score, MWoA were divided into twenty in the SDS (+) (SDS > 49) group and 20 in the SDS (−) (SDS ≤ 49) group. Regional homogeneity (ReHo) method were employed to assess local features of spontaneous brain activity between 1) all MWoA and healthy controls, 2) each subgroup and healthy controls, and 3) SDS (−) group and SDS (+) group.

Results

Compared with healthy controls, decreased ReHo in similar regions were shown in the MWoA group and subgroups. It is noteworthy that the caudate showed increased ReHo in the SDS (−) group compared with healthy controls and the SDS (+) group. Moreover, the average ReHo values of the caudate in SDS (−) group were significantly positively correlated with duration of migraine.

Conclusions

Our results suggested that ReHo patterns in migraine patients may be affected by depressive symptoms and serve as a biomarker to reflect depression severity in MWoA.

Alterations of regional spontaneous neuronal activity and corresponding brain circuit changes during resting state in migraine without aura

Although previous resting-state studies have reported abnormal functional cerebral changes in patients with migraine without aura (MwoA), few have focused on alterations in both regional spontaneous neuronal activity and corresponding brain circuits in MwoA patients during rest. Eighteen MwoA patients and 18 age- and gender-matched healthy controls (HC) were recruited in the current study. Baseline cerebral alterations were investigated using amplitude of low-frequency fluctuation (ALFF) and region of interest (ROI)-based functional connectivity (FC) analyses. Compared with HC, MwoA patients showed decreased ALFF values in the left rostral anterior cingulate cortex (rACC) and bilateral prefrontal cortex (PFC) as well as increased ALFF values in the right thalamus. FC analysis also revealed abnormal FCs associated with these ROIs. In addition, ALFF values of the left rACC correlated with duration of disease in MwoA. Our findings could lead to a better understanding of intrinsic functional architecture of baseline brain activity in MwoA, providing both regional and brain circuit spontaneous neuronal activity properties.

Structural and functional abnormalities in migraine patients without aura

Migraine is a primary headache disorder characterized by recurrent attacks of throbbing pain associated with neurological, gastrointestinal and autonomic symptoms. Previous studies have detected structural deficits and functional impairments in migraine patients. However, researchers have failed to investigate the functional connectivity alterations of regions with structural deficits during the resting state. Twenty-one migraine patients without aura and 21 age- and gender-matched healthy controls participated in our study. Voxel-based morphometric (VBM) analysis and functional connectivity were employed to investigate the abnormal structural and resting-state properties, respectively, in migraine patients without aura. Relative to healthy comparison subjects, migraine patients showed significantly decreased gray matter volume in five brain regions: the left medial prefrontal cortex (MPFC), dorsal anterior cingulate cortex (dACC), right occipital lobe, cerebellum and brainstem. The gray matter volume of the dACC was correlated with the duration of disease in migraine patients, and thus we chose this region as the seeding area for resting-state analysis. We found that migraine patients showed increased functional connectivity between several regions and the left dACC, i.e. the bilateral middle temporal lobe, orbitofrontal cortex (OFC) and left dorsolateral prefrontal cortex (DLPFC). Furthermore, the functional connectivity between the dACC and two regions (i.e. DLPFC and OFC) was correlated with the duration of disease in migraine patients. We suggest that frequent nociceptive input has modified the structural and functional patterns of the frontal cortex, and these changes may explain the functional impairments in migraine patients.

Intrinsic brain network abnormalities in migraines without aura revealed in resting-state fMRI

BACKGROUND

Previous studies have defined low-frequency, spatially consistent intrinsic connectivity networks (ICN) in resting functional magnetic resonance imaging (fMRI) data which reflect functional interactions among distinct brain areas. We sought to explore whether and how repeated migraine attacks influence intrinsic brain connectivity, as well as how activity in these networks correlates with clinical indicators of migraine.

METHODS/PRINCIPAL FINDINGS

Resting-state fMRI data in twenty-three patients with migraines without aura (MwoA) and 23 age- and gender-matched healthy controls (HC) were analyzed using independent component analysis (ICA), in combination with a "dual-regression" technique to identify the group differences of three important pain-related networks [default mode network (DMN), bilateral central executive network (CEN), salience network (SN)] between the MwoA patients and HC. Compared with the HC, MwoA patients showed aberrant intrinsic connectivity within the bilateral CEN and SN, and greater connectivity between both the DMN and right CEN (rCEN) and the insula cortex - a critical region involving in pain processing. Furthermore, greater connectivity between both the DMN and rCEN and the insula correlated with duration of migraine.

CONCLUSIONS

Our findings may provide new insights into the characterization of migraine as a condition affecting brain activity in intrinsic connectivity networks. Moreover, the abnormalities may be the consequence of a persistent central neural system dysfunction, reflecting cumulative brain insults due to frequent ongoing migraine attacks.

Prostaglandin E(2) induces immediate migraine-like attack in migraine patients without aura

BACKGROUND

Prostaglandin E(2) (PGE(2)) has been suggested to play an important role in the pathogenesis of migraine. In the present experiment we investigated if an intravenous infusion of PGE(2) would induce migraine-like attacks in patients with migraine.

METHODS

Twelve patients with migraine without aura were randomly allocated to receive 0.4 µg/kg/min PGE(2) (Prostin(®)E2, dinoprostone) or placebo over 25 minutes in a two-way, crossover study. Headache intensity was recorded on a verbal rating scale, middle cerebral artery blood flow velocity (V(MCA)) was measured by transcranial Doppler (TCD) and diameter of the superficial temporal artery (STA) was obtained by c-series scan (Dermascan C).

RESULTS

In total, nine migraine patients (75%) experienced migraine-like attacks after PGE(2) compared to none after placebo (p = 0.004). Seven out of 9 (58%) patients reported the migraine-like attacks during the immediate phase (0-90 min) (p = 0.016). Only two patients experienced the delayed migraine-like attacks several hours after the PGE(2) infusion stop (p = 0.500). The V(MCA) decreased during the PGE(2) infusion (p = 0.005) but there was no significant dilatation of the STA (p = 0.850).

CONCLUSION

The migraine-like attacks during, and immediately after, the PGE(2) infusion contrast with those found in previous provocation studies, in which the other pharmacological compounds triggered the delayed migraine-like attacks several hours after the infusion. We suggest that PGE(2) may be one of the important final products involved in the generation of migraine attacks.

Regional homogeneity abnormalities in patients with interictal migraine without aura: a resting-state study

Previous studies have provided evidence of structural and task-related functional changes in the brains of patients with migraine without aura. Resting-state brain activity in patients with migraine provides clues to the pathophysiology of the disease. However, few studies have focused on the resting-state abnormalities in patients with migraine without aura. In the current study, we employed a data-driven method, regional homogeneity (ReHo), to analyze the local features of spontaneous brain activity in patients with migraine without aura during the resting state. Twenty-six patients with migraine without aura and 26 age-, education- and gender-matched healthy volunteers participated in this study. Compared with healthy controls, patients with migraine without aura showed a significant decrease in ReHo values in the right rostral anterior cingulate cortex (rACC), the prefrontal cortex (PFC), the orbitofrontal cortex (OFC) and the supplementary motor area (SMA). In addition, we found that ReHo values were negatively correlated with the duration of disease in the right rACC and PFC. Our results suggest that the resting-state abnormalities of these regions may be associated with functional impairments in pain processing in patients with migraine without aura. We hope that our results will improve the understanding of migraine.

Detection and discrimination of flicker contrast in migraine

AIMS

Flickering light is strongly aversive to many individuals with migraine. This study was designed to evaluate other abnormalities in the processing of temporally modulating visual stimulation.

METHODS

We measured psychophysical thresholds for detection of a flickering target and for the discrimination of suprathreshold flicker contrasts (increment thresholds) in 14 migraineurs and 14 healthy controls with and without prior adaptation to high-contrast flicker. Visual discomfort (aversion) thresholds were also assessed.

RESULTS

In the baseline (no adaptation) conditions, detection and discrimination thresholds did not differ significantly between groups. Following adaptation, flicker detection thresholds were elevated equivalently in both groups; however, discrimination thresholds were more strongly affected in migraineurs than in controls, showing greater elevation at moderate contrasts and greater threshold reduction (sensitisation) at high contrast (70%). Migraineurs also had significantly elevated discomfort scores, and these were significantly correlated with number of years with migraine.

DISCUSSION

We conclude that visual flicker not only causes discomfort but also exerts measurable effects on contrast processing in the visual pathways in migraine. The findings are discussed in the context of the existing literature on habituation, adaptation and contrast-gain control.

Patients with migraine with aura have increased flow mediated dilation

BACKGROUND

Endothelium-derived nitric oxide (NO) mediates the arterial dilation following a flow increase (i.e. flow-mediated dilation, FMD), easily assessed in the brachial artery. NO is also involved in cerebral hemodynamics and it is supposed to trigger vascular changes occurring during migraine. This study aimed at investigating whether migraine patients present an altered response to NO also in the peripheral artery system.

METHODS

We enrolled 21 migraineurs (10 with aura [MwA], 11 without aura [MwoA]), and 13 controls. FMD was evaluated with ultrasound in all subjects by measuring the percentage increase of the brachial artery diameter induced by hyperaemia reactive to sustained cuff inflation around the arm above systolic pressure. FMD values were then normalized for shear stress.

RESULTS

Normalized FMD values were higher in patients with MwA (28.5 10-2%.s) than in controls (9.0 10-2%.s) and patients with MwoA (13.7 10-2%.s) (p < 0.001). FMD was over the median value (19%) in 23.1% of controls, in 45.5% of the MwoA patients, and in 90% of the MwA patients.

CONCLUSIONS

Migraineurs with aura present an excessive arterial response to hyperaemia, likely as an effect of an increased sensitivity to endothelium-derived nitric oxide. This phenomenon observed peripherally might reflect similar characteristics in the cerebral circulation.

Somatosensory evoked potentials in children with migraine with aura and without aura

BACKGROUND

The Interictal abnormalities of cerebral information processing in migraine were found by studying different modality-specific evoked and event related potentials, mostly visual and auditory. In this study we focused on short-latency somatosensory evoked potentials (SEP) in children and adolescents suffering from migraine with and without aura.

MATERIAL AND METHODS

The study group consisted 111 of children and adolescents at the age of 7-18 years: 27 of them suffered from migraine with aura, 36 of them suffered from migraine without aura, 48 subjects have episodic tension-type headache. SEPs was performed interictally at least two days after the last headache attack.

RESULTS

There were no significant differences in the latency averages of SEP components between all migraneurs and tension-type headache subjects. However, N9 and N13 latency averages were significantly shorter in migraine without aura group compared with migraine with aura and tensiom type headaches. We did not find any significant correlations for either headache type between evoked potentials parametrs and illness duration, unilateral localisation of pain, migraine in family and aura.

CONCLUSIONS

In concert with similar studies in adult migraineurs, our findings showed no disturbances of somatosensory information processing in children with migraine with aura and without aura. The diagnosis of migraine in children actually remains predominantly based on medical history. However, electrophysiological techniques allow the study of some of the structures in vivo and enlarge our knowledge on controversial aspects of migraine pathophysiology.

Increased baroreflex sensitivity and heart rate variability in migraine patients

OBJECTIVES

We investigated whether spontaneous baroreflex sensitivity and heart rate variability (HRV) are different in migraine patients compared to healthy controls.

MATERIAL AND METHODS

Sixteen female migraine patients without aura aged 18-30 years and 14 age-matched healthy female controls were included. Continuous finger blood pressure and ECG were measured supine during paced breathing in the laboratory. Continuous finger blood pressure was measured the following 24-h period. Spontaneous baroreflex sensitivity (time-domain cross correlation baroreflex sensitivity) as well as HRV parameters were calculated.

RESULTS

Spontaneous baroreflex sensitivity measured in the 24-h period was increased in patients (20.6 ms/mmHg) compared to controls (15.7 ms/mmHg, P = 0.031). HRV parameters were increased during paced breathing in patients (P < 0.045).

CONCLUSIONS

The results suggest that central hypersensitivity in migraine also includes cardiovascular reactivity and may be important for the understanding of the mechanisms for the effect of antihypertensive drugs for migraine prophylaxis.

Migraine presenting as chronic facial pain

We report the case of a 44-year-old woman with chronic facial pain. She was treated with several analgesics, prophylactic medications and infiltrations, but all treatment modalities were ineffective. Finally, the diagnosis of medication-overuse headache complicating migraine without aura was made and an appropriate treatment was initiated. Migraine is a very common primary headache and rarely presents as isolated facial pain. Stimulation of the dura with activation of the trigeminovascular system can result in pain in any of the three divisions of the trigeminal nerve. This is the anatomic basis of migraine pain presenting as referred pain to the second division of the trigeminal nerve. The atypical presentation of migraine pain can easily lead to inappropriate treatment regimens.

Visual evoked potential and spatial frequency in migraine: a longitudinal study

OBJECTIVES

Reduced habituation of visual evoked potentials (VEP) has been reported in migraine. We aimed to study if preattack excitability changes were related to check size using a paired longitudinal design.

MATERIALS AND METHODS

Magnocellular and parvocellular functions were studied with monocular 31 and 62 checks in 33 adult migraine patients without aura (MwoA), 8 with aura (MA) and 31 controls. VEP was recorded in four blocks of 50 stimuli. N1P1 and P1N2 amplitudes were measured. Sessions were classified as preattack or interictal.

RESULTS

MA patients had significantly higher P1N2 and N1P1 amplitude than the controls and MwoA. VEP amplitude habituation was not found in controls. Migraine patients had significantly higher P1N2 amplitude before the attack compared with a paired interictal recording for large checks.

CONCLUSIONS

Cortical excitability is high in MA. Headache severity affects visual excitability. Increased P1N2 VEP amplitude before the attack suggests a cyclic decreased intracortical inhibition in extrastriate magnocellular pathways in migraine.

Jactatio extra-capitis and migraine suppression

Sleep often terminates migraine headaches, and sleep disorders occur with greater prevalence in individuals with chronic or recurrent headaches. Rhythmic head, limb or body movements are common in children before falling asleep, but they very rarely persist into adolescence and adulthood, or appear de novo later in life as sleep-related rhythmic movement disorders. A 22-year-old female with migraine without aura and history of early childhood pre-dormital body rocking (jactatio) discovered that unilateral slow rhythmic movements of her right foot greatly facilitated falling sound asleep while reclining. Sleep served every time to terminate her migraine attack. Rhythmic movements may serve on occasion as a therapeutic hypnotic maneuver in migraine sufferers.

[The mechanism of peripheral and central sensitization in migraine. A literature review]

Migraine attacks are characterized by unilateral throbbing, pulsating headache associated with nausea, vomiting, photophobia, phonophobia and allodynia. Peripheral sensitization is an acute, chemical-induced form of functional plasticity, which converts high-threshold nociceptors into low-threshold sensory neurons. This form of sensitization occurs when the nerve terminals (meningeal nociceptors) of the neurons of the trigeminal ganglion are soaked with the "inflammatory" soup (prostaglandin E2, bradykinin, serotonin and cytokines) along the vasculature of the cerebral dura mater. Peripheral sensitization in migraine attacks is explained clinically by intracranial hypersensitivity (the headache worsens during coughing or physical activity) and by a throbbing element in the pain of migraine (sensitized nociceptors become hyperresponsive to the otherwise innocuous and unperceived rhythmic fluctuation in intracranial pressure produced by normal arterial pulsation). The essence of central sensitization is that the second-order neurons in the trigeminocervical complex become hyperexcitable. The altered behavior of the second-order neurons is based on the increased glutamate sensistivity of the NMDA receptors and the neuronal nitric oxide synthase activity stimulated by nitric oxide. This process is explained clinically by face and scalp ollodynia and by neck stiffness (extracranial tenderness).

The middle meningial artery during a migraine attack: 3T magnetic resonance angiography study

We performed 3T magnetic resonance angiography (MRA) during a spontaneous migraine attack. The patient was a 42-year-old woman migraineur diagnosed by the IHS criteria. The change of the middle meningial artery (MMA) was measured on the axial brain images using MATLAB for three phases (attack-free period, during an attack, a period after medication). There were no dramatic changes of vasodilation in the MMA during the attack (2.0 mm), attack-free period (diameter 1.9 mm), or period after medication (1.7 mm), resembling extrapolations of observations in experimental animal models. This finding suggests that the dramatic vasomotion might not be associated with migraine pathophysiology.

The effects of magnesium prophylaxis in migraine without aura

There are inconsistent findings about the efficacy of magnesium in the prophylaxis of migraine attacks and there is no study of magnesium prophylaxis focused on migraine subtypes without aura. In this double blind, randomized, placebo controlled study; we tried to evaluate the prophylactic effects of oral magnesium in migraine patients without aura. The prophylactic effects of 600 mg/day oral magnesium citrate supplementation were assessed by means of clinical evaluation, visual evoked potential and statistical parametric mapping of brain single photon emission computerized tomography before and after a 3 month treatment period. The results of 30 patients with migraine without aura (20-55 years old with 2-5 migraine attacks per month) on magnesium treatment were compared with those of 10 patients with similar properties on placebo treatment. Migraine attack frequency, severity and P1 amplitude in visual evoked potential examination decreased after magnesium treatment with respect to pretreatment values (p < 0.001). In a comparison of the effects of magnesium treatment with those of placebo, post/pretreatment ratios of migraine attack frequency, severity and P1 amplitude in Mg treatment group were found to be significantly lower than those in placebo treatment group (attack frequency p = 0.005, attack severity p < 0.001, P1 amplitude p < 0.05). Cortical blood flow in inferolateral frontal (p < 0.001), inferolateral temporal (p = 0.001) and insular regions (p < 0.01) increased significantly after magnesium treatment with respect to the pretreatment; while such significant changes of cortical blood flow were not observed with placebo treatment. These results have made us think that magnesium is a beneficial agent in prophylaxis of migraine without aura and might work with both vascular and neurogenic mechanisms.

Clinical correlates of phosphene perception in migraine without aura: An Asian study

INTRODUCTION

Although controversy exists with regard to the presence of hypoexcitability versus hyperexcitability of the visual cortex in migraine patients, there remain a group who do not perceive phosphenes (P-). However, its clinical implications have not been systematically addressed. In this study, we hypothesize that P- patients classified as migraine without aura (MO) have distinct clinical features.

METHODS

Twenty-nine Asian MO patients (7 men; mean age: 44; median: 45; range: 25 to 65) were consecutively entered into the study. Visual cortex transcranial magnetic stimulation (TMS) was performed in the migraine interictum.

RESULTS

Of the 19 patients, 19 (66%) were able to perceive phosphenes (P+), while 10 (34%) were not able to after repeated TMS (P-). P- patients had significantly higher headache frequency (p=0.008) and pain score (p=0.002) compared with P+ patients. In addition, there was significant positive correlation of phosphene threshold with pain score (r=0.52, p=0.02) in P+ patients. There was no significant difference between P+ and P- patients in terms of age (t-test, p=0.6).

CONCLUSIONS

Our study is inkeeping with the hypothesis that interictal visual cortex excitability is reduced in relation to the severity of migraine in Asian MO patients, and lack of phosphene perception may be related to significantly elevated thresholds beyond the output of TMS stimulators.

Massaging over the greater occipital nerve reduces the intensity of migraine attacks: evidence for inhibitory trigemino-cervical convergence mechanisms

Activation of the trigemino-cervical system constitutes one of the first steps in the genesis of migraine. The objective of this study was to confirm the presence of trigemino-cervical convergence mechanisms and to establish whether such mechanisms may also be of inhibitory origin. We describe a case of a 39-years-old woman suffering from episodic migraine who showed a significant improvement in her frontal headache during migraine attacks if the greater occipital nerve territory was massaged after the appearance of static mechanical allodynia (cortical sensitization). We review trigemino-cervical convergence and diffuse nociceptive inhibitory control (DNIC) mechanisms and suggest that the convergence mechanisms are not only excitatory but also inhibitory.

[Observation on the therapeutic effect of ear point combined therapy on common migraine at the remission stage and effects on plasma CGRP and ET in the patient]

OBJECTIVE

To probe into the therapeutic effect of ear point combined therapy on common migraine at the remission stage and the mechanism.

METHODS

Thirty-two cases of common migraine at the remission stage were treated with ear point combined therapy, including blood-letting at ear back, injection of autoblood into Fengchi (GB 20), Yanglingquan (GB 34), and pricking at ear points Nie, Yi-dan (pancreas and gallbladder), Shenmen, etc.. Clinical therapeutic effect was evaluated at the end of one therapeutic course, and calcitonin gene-related peptide (CGRP) and endotheline (ET) were detected before and after treatment, and the CGRP and ET contents were compared with those in 22 normal persons.

RESULTS

The effective rate was 78.1% (P<0.001), CGRP and ET contents had very significant changes after treatment (P<0.01), and CGRP and ET showed negative correlativity (P<0.05).

CONCLUSION

The ear point combined therapy can regulates the balance between the plasma CGRP and ET in the patient of common migraine and improve vasodilative, vasoconstrictive and endothelial fuctions in the brain, hence stopping pain.

Effects of remote cutaneous pain on trigeminal laser-evoked potentials in migraine patients

The present study aimed to evaluate heat pain thresholds and evoked potentials following CO(2) laser thermal stimulation (laser-evoked potentials, LEPs), during remote application of capsaicin, in migraine patients vs. non-migraine healthy controls. Twelve outpatients suffering from migraine without aura were compared with 10 healthy controls. The LEPs were recorded by 6 scalp electrodes, stimulating the dorsum of the right hand and the right supraorbital zone in basal condition, during the application of 3% capsaicin on the dorsum of the left hand and after capsaicin removal. In normal subjects, the laser pain and the N2-P2 vertex complex obtained by the hand and face stimulation were significantly reduced during remote capsaicin application, with respect to pre-and post-capsaicin conditions, while in migraine LEPs and laser pain were not significantly modified during remote painful stimulation. In migraine a defective brainstem inhibiting control may coexist with cognitive factors of focalised attention to facial pain, less sensitive to distraction by a second pain.

Impairment in Color Perception in Migraine With and Without Aura

OBJECTIVE

To assess visual perception in 40 patients suffering from migraine with aura (MA), 40 patients suffering from migraine without aura (MO), and 40 controls.

BACKGROUND

Visual perception abnormalities are a common feature in both MA and MO.

METHODS

We performed luminance and color central perimetry. Black and white pattern reversal visual-evoked potentials were also assessed.

RESULTS

Luminance perimetry was similar in patients and controls. Color perimetry instead revealed an impairment in the perception of red ("quantitative perception index") in migraine patients; this impairment was more pronounced in patients with MA (P < .001) than in those with MO (P < .05) and was related to the degree of photophobia recorded before testing. A subgroup of MO patients who had a migraine attack shortly after being tested also displayed a marked impairment in the perception of blue. This subgroup of patients had a statistically significant (P < .001) lower perception of blue than the rest of the MO patients, who had a migraine attack later; they also had a high degree of unpleasant perceptions after testing. Black and white visual evoked potentials were similar in patients and controls.

CONCLUSION

The impairment in visual perception of red, which was more marked in MA than in MO patients, may be related to the degree of photophobia recorded before testing. The reduced perception of blue, which only occurred in a subgroup of MO patients in the premonitory phase of the migraine attack, probably occurs through mechanisms that involve dopaminergic function. We cannot exclude the possibility that the visual stimulations induced the migraine attack in this subgroup of MO patients shortly after they were tested.

Transcranial direct current stimulation reveals inhibitory deficiency in migraine

The issue of interictal excitability of cortical neurons in migraine patients is controversial: some studies have reported hypo-, others hyperexcitability. The aim of the present study was to observe the dynamics of this basic interictal state by further modulating the excitability level of the visual cortex using transcranial direct current stimulation (tDCS) in migraineurs with and without aura. In healthy subjects anodal tDCS decreases, cathodal stimulation increases transcranial magnetic stimulation (TMS)-elicited phosphene thresholds (PT), which is suggested as a representative value of visual cortex excitability. Compared with healthy controls, migraine patients tended to show lower baseline PT values, but this decrease failed to reach statistical significance. Anodal stimulation decreased phosphene threshold in migraineurs similarly to controls, having a larger effect in migraineurs with aura. Cathodal stimulation had no significant effect in the patient groups. This result strengthens the notion of deficient inhibitory processes in the cortex of migraineurs, which is selectively revealed by activity-modulating cortical input.

Habituation of sympathetic skin response in migraine and tension type headache

This study aimed to investigate the changes of habituations in the autonomic function of patients suffering from migraine or tension type headache through sympathetic skin responses. Patients with migraine without aura (n=26), with episodic tension type headache without migraine (n=28) and 30 healthy controls were studied. During continuous stimulation, four blocks of 20 responses were sequentially recorded. Mean amplitude changes in the second, third and fourth blocks are expressed as the percentages of the first block. In both headache groups, there was a lack of habituation compared to the control group.

Intracortical Inhibition and Facilitation in Migraine-A Transcranial Magnetic Stimulation Study

OBJECTIVE

Migraine is a disease of altered cortical excitability between attacks. However, the mechanisms of abnormal excitability in migraine are insufficiently investigated. Hence, the aim of the study was to investigate intracortical inhibition/facilitation of the motor circuit in migraine.

METHODS

Sixteen women suffering from migraine without aura and 15 healthy women were investigated using a suprathreshold transcranial magnetic stimulation (TMS) in the paired-pulse paradigm with long interstimulus intervals (ISI = 20, 60, 120 ms) and measurement of the cortical silent period.

RESULTS

We found no differences for the cortical silent period and for the long intracortical inhibition between the groups. Concerning intracortical facilitation, this ability was significantly more pronounced in patients suffering from migraine compared with healthy controls.

CONCLUSION

Migraineurs produce an increased intracortical facilitation. The results may be discussed in line of glutamatergic mechanisms in migraine, which could be related to altered facilitation.