Abnormal causal connectivity of anterior cingulate cortex-visual cortex circuit related to nonsteroidal anti-inflammatory drug efficacy in migraine

The anterior cingulate cortex (ACC) and visual cortex are integral components of the neurophysiological mechanisms underlying migraine, yet the impact of altered connectivity patterns between these regions on migraine treatment remains unknown. To elucidate this issue, we investigated the abnormal causal connectivity between the ACC and visual cortex in patients with migraine without aura (MwoA), based on the resting-state functional magnetic resonance imaging data, and its predictive ability for the efficacy of nonsteroidal anti-inflammatory drugs (NSAIDs). The results revealed increased causal connectivity from the bilateral ACC to the lingual gyrus (LG) and decreased connectivity in the opposite direction in nonresponders compared with the responders. Moreover, compared with the healthy controls, nonresponders exhibited heightened causal connectivity from the ACC to the LG, right inferior occipital gyrus (IOG) and left superior occipital gyrus, while connectivity patterns from the LG and right IOG to the ACC were diminished. Based on the observed abnormal connectivity patterns, the support vector machine (SVM) models showed that the area under the receiver operator characteristic curves for the ACC to LG, LG to ACC and bidirectional models were 0.857, 0.898, and 0.939, respectively. These findings indicate that neuroimaging markers of abnormal causal connectivity in the ACC-visual cortex circuit may facilitate clinical decision-making regarding NSAIDs administration for migraine management.

Retinal nerve fiber layer changes in migraine: A protocol for systematic review and meta-analysis

BACKGROUND

Migraine is a common neurological disease, which seriously affects the quality of life and daily activities of patients. Although migraine is a transient phenomenon of cerebral vasoconstriction, it is well documented that recurrent attacks of migraine may lead to abnormalities in retinal structure. Optical coherence tomography (OCT) is a sensitive method to detect subtle damage in retinal nerve fiber layer (RNFL). There have been many studies investigating the difference in RNFL thickness with optical coherence tomography (OCT) between migraine patients and healthy controls. However, the results were not consistent. Our purpose is to perform a meta-analysis to investigate RNFL alterations in migraine.

METHODS

We will search PubMed, Embase, Web of science for studies assessing the differences in RNFL measured by OCT between patients with migraine and healthy controls. Case-control studies published in English will be included. Two reviewers will independently screen eligible articles, extract data, and assess quality. This meta-analysis will synthesize selected research data and compare the difference in RNFL thickness between patients with migraine and healthy controls. We will use Stata 15 in this meta-analysis. I statistics will be used to assess heterogeneity. If I ≤ 50%, the data are synthesized will use a fixed effect model. Otherwise, a random effect model will be performed. Publication bias will be determined by the Egger test. The methodological quality of all included studies will be evaluated by the Newcastle-Ottawa Scale (NOS). We will perform subgroup analysis, sensitivity analysis, and meta-regression analysis to test the robustness of the results.

RESULTS

We will obtain quantitative results regarding the difference in RNFL thickness between migraine patients and healthy controls. The results will be published in a peer-reviewed journal.

CONCLUSIONS

The results of this study provide a high-quality synthesis of existing evidence and provide a basis for assessing the effect of migraine on the thickness of RNFL.

REGISTRATION NUMBER

INPLASY 202060033.

Structural changes of cerebellum and brainstem in migraine without aura

BACKGROUND

Increasing evidence has suggested that the cerebellum is associated with pain and migraine. In addition, the descending pain system of the brainstem is the major site of trigeminal pain processing and modulation and has been discussed as a main player in the pathophysiology of migraine. Cerebellar and brainstem structural changes associated with migraineurs remain to be further investigated.

METHODS

Voxel-based morphometry (VBM) (50 controls, 50 migraineurs without aura (MWoAs)) and diffusion tensor imaging (DTI) (46 controls, 46 MWoAs) were used to assess cerebellum and brainstem anatomical alterations associated with MWoAs. We utilized a spatially unbiased infratentorial template toolbox (SUIT) to perform cerebellum and brainstem optimized VBM and DTI analysis. We extracted the average diffusion values from a probabilistic cerebellar white matter atlas to investigate whether MWoAs exhibited microstructure alterations in the cerebellar peduncle tracts.

RESULTS

MWoAs showed decreased fractional anisotropy (FA) in the vermis VI extending to the bilateral lobules V and VI of the cerebellum. We also found higher axial diffusivity (AD), mean diffusivity (MD), and radial diffusivity (RD) in the right inferior cerebellum peduncle tract in MWoAs. MWoAs exhibited both reduced gray matter volume and increased AD, MD and RD in the spinal trigeminal nucleus (SpV).

CONCLUSION

MWoAs exhibited microstructural changes in the cerebellum and the local brainstem. These structural differences might contribute to dysfunction of the transmission and modulation of noxious information, trigeminal nociception, and conduction and integration of multimodal information in MWoAs. These findings further suggest involvement of the cerebellum and the brainstem in the pathology of migraine without aura.

Structural abnormalities in the thalamus of migraineurs with aura: a multiparametric study at 3 T

BACKGROUND AND OBJECTIVES

The thalamus exerts a pivotal role in pain processing and cortical excitability control, and migraine is characterized by repeated pain attacks and abnormal cortical habituation to excitatory stimuli. This work aimed at studying the microstructure of the thalamus in migraine patients using an innovative multiparametric approach at high-field magnetic resonance imaging (MRI).

DESIGN

We examined 37 migraineurs (22 without aura, MWoA, and 15 with aura, MWA) as well as 20 healthy controls (HC) in a 3-T MRI equipped with a 32-channel coil. We acquired whole-brain T1 relaxation maps and computed magnetization transfer ratio (MTR), generalized fractional anisotropy, and T2* maps to probe microstructural and connectivity integrity and to assess iron deposition. We also correlated the obtained parametric values with the average monthly frequency of migraine attacks and disease duration.

RESULTS

T1 relaxation time was significantly shorter in the thalamus of MWA patients compared with MWoA (P < 0.001) and HC (P ≤ 0.01); in addition, MTR was higher and T2* relaxation time was shorter in MWA than in MWoA patients (P < 0.05, respectively). These data reveal broad microstructural alterations in the thalamus of MWA patients compared with MWoA and HC, suggesting increased iron deposition and myelin content/cellularity. However, MWA and MWoA patients did not show any differences in the thalamic nucleus involved in pain processing in migraine.

CONCLUSIONS

There are broad microstructural alterations in the thalamus of MWA patients that may underlie abnormal cortical excitability control leading to cortical spreading depression and visual aura.

White matter integrity affected by depressive symptoms in migraine without aura: a tract-based spatial statistics study

Previous studies have proven that migraine and depression are bidirectionally linked. However, few studies have investigated white matter (WM) integrity affected by depressive symptoms in patients suffering from migraine without aura (MWoA). Forty patients with MWoA were divided into two groups according to their self-rating depression scale (SDS) score in the present study, including 20 in the SDS (+) (SDS > 49) group and 20 in the SDS (-) (SDS ≤ 49) group. Forty healthy participants were also recruited as the control group. Tract-based spatial statistics analyses with multiple diffusion tensor imaging-derived indices [fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), axial diffusivity (AD)] were employed collectively to investigate WM integrity between all patients with MWoA and all healthy controls, between each subgroup (SDS (-) group and SDS (+) group) and healthy controls, and between the SDS (-) and SDS (+) groups. Compared with healthy controls, decreased AD was shown in several WM tracts of the whole MWoA group, SDS (-) group and SDS (+) group. In addition, compared with the SDS (-) group, the SDS (+) group showed decreased FA and increased MD and RD, with conserved AD, including the genu, body and splenium of the corpus callosum, bilateral superior longitudinal fasciculi, the right anterior corona radiata and some other WM tracts, similar to previous findings in depression disorder. Furthermore, mean FA and RD in some of the above-mentioned WM tracts in the SDS (+) group were correlated significantly with SDS scores, including the genu and splenium of the corpus callosum, the right anterior corona radiata and the superior longitudinal fasciculi. Our results suggest that WM integrity may be affected by both depression symptoms (more sensitive as RD) and migraine (more sensitive as AD). The findings may serve as a sensitive biomarker of depression severity in MWoA.

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.

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.

Volumetric evaluation of hemicerebellar changes in migraine patients without aura

Brain balance changes have been recognised in migraine, but cerebellar function between or during attacks has been assessed only in a few studies. Previous studies have indicated that migraine affects cerebellar function. In the present study we aimed to evaluate the hemicerebellar volume changes of patients with migraine without aura (MWoA). Volumetric changes of cerebellar hemispheres were evaluated in terms of asymmetry using stereological methods on magnetic resonance images (MRI) retrospectively. Nineteen patients with MWoA and 18 age- and gender-matched control subjects were included in the study. MRIs were analysed by using the point-counting approach of stereological methods by Cavalier's principle. There was no statistically significant cerebellar atrophy or hemicerebellar asymmetry between the MWoA and control subjects. There was no cerebellar atrophy or asymmetry between the MWoA and age-matched control group. The stereological evaluation of cerebellar asymmetry and atrophy in humans is important for both clinicians and anatomists. The technique is simple, inexpensive, and reliable.

[Modern methods of neurovisualization and preventive treatment of migraine]

Forty-eight patients have been examined in the Centre of Headache Treatment. MRI of the brain revealed the changes in the white matter in 69% of patients, 39% had multiple foci (more than 3). The largest number of foci was seen in patients with frequent and chronic migraine without aura, but not in those with migraine with aura. The foci were located more often in frontal areas and less often in parietal and temporal areas. Twenty-three patients with frequent and chronic migraine received the preventive treatment with the anticonvulsant topiramate (topamax, capsules 25 and 50 mg). The duration of treatment was from 4 to 12 months depending on the disease severity. The decrease in frequency of migraine attacks was seen after 1 month of the treatment. After 6 months, mean score on the MIDAS decreased from 26.5 that indicated the severity of migraine and significant decrease in working capacity to 5.7 that corresponded to the mild form of migraine.

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.

Scanning laser polarimetry with variable corneal compensation in migraine patients

PURPOSE

 This study aimed to compare scanning laser polarimetry measurements of retinal nerve fibre layer (RNFL) thickness in eyes of migraine patients with those in eyes of age-matched, healthy subjects.

METHODS

 The study was designed as an observational, prospective, cross-sectional study. It included 57 eyes of 57 patients with migraine with or without aura according to the criteria of the International Headache Society and 44 eyes of 44 age-matched healthy controls. Scanning laser polarimetry images were obtained using a commercial GDx VCC system (Version 5.3.1; Laser Diagnostic Technologies, Inc.). At each sitting, three sets of GDx VCC measurements were acquired for each patient and used in the analysis. Image acquisition was performed in undilated eyes in all subjects.

RESULTS

 The mean ± standard deviation RNFL average thickness parameter in the migraine subjects was significantly lower than in the control group, at 50.4 ± 4.8 μm versus 54.7 ± 3.4 μm, respectively (p < 0.0001). However, there were no differences between migraine subjects and controls in mean RNFL thickness in superior and inferior areas. In the migraine group the mean migraine disability assessment (MIDAS) score was 34.3 ± 15.3 and the mean number of attacks per year was 17.1 ± 6.9 (range 6-28). The mean RNFL average thickness parameter was significantly correlated with MIDAS score (r = - 0.86, p < 0.0001) and frequency of attacks (r = - 0.86, p < 0.0001).

CONCLUSIONS

The mean RNFL average thickness parameter was found to be thinner in migraine patients. In addition, we found a strong correlation between migraine severity and RNFL average thickness parameters.

[Effect of ear point combined therapy on plasma substance P in patients of no-aura migraine at different stages]

OBJECTIVE

To evaluate the therapeutic effect of ear point combined therapy on no-aura migraine at different stages and the mechanism.

METHODS

Thirty cases of no-aura migraine at different stages were treated with ear point combined therapy, including blood-letting at the ear back, injection of auto-blood into Fengchi (GB 20), Yanglingquan (GB 34), and pricking at ear points Nie (AT2), Yidan (CO11), Shenmen (TF4), etc. Their clinical therapeutic effects were evaluated at the end of one therapeutic course, and substance P (SP) contents were detected before and after treatment.

RESULTS

The clinical effective rate was 86.7%, and the effective rate was 87.5% at the attack stage and 86.4% at the remission stage with no significant difference between the attack stage and the remission stage (P>0.05); after treatment, SP content had significant change as compared with that before treatment (P<0.05, P<0.01), and there was very significant difference in SP content between the attack stage before treatment and the remission stage (P<0.01).

CONCLUSION

The ear point combined therapy can relieve pain possibly through decreasing plasma SP content, and the SP con tent possibly is one of main factors inducing migraine attack.

Cerebrospinal fluid sodium increases in migraine

BACKGROUND

Pharmaceuticals with calcium- or sodium-channel-blocking activity have proven useful for migraine prophylaxis, and calcium channel, sodium transporter, and sodium channel gene mutations have been found in familial hemiplegic migraine. However, it is not known whether calcium or sodium homeostasis is altered in migraine.

OBJECTIVE

To compare levels of sodium, calcium, potassium, and magnesium in cerebrospinal fluid (CSF) and blood plasma between migraineurs and controls.

METHODS

We recruited 20 migraineurs without aura and 11 controls prospectively, and studied migraineurs in sick (MH(+)) and well (MH(-)) states. We collected lumbar CSF and venous blood plasma, quantified elements with ion-selective electrodes or colorimetry, and determined osmolality by depression of freezing point. We compared levels of Na(+), Ca(2+), K(+), and Mg among and also within subjects who were studied in both MH(+) and MH(-) states.

RESULTS

Mean CSF Na(+) levels were increased by 3 mmol/L in MH(+) compared with MH(-) and by 4 mmol/L compared to controls (P < 0.005). In 4 subjects who were sampled in both MH(+) and MH(-) states, mean CSF Na(+) concentration increased by 2 mmol/L in the MH(+) state compared with the MH(-) state (P < 0.05). Simultaneous plasma Na(+) levels did not differ among the 3 clinical groups, nor did osmolality, total Ca and Ca(2+), K(+), and total Mg levels in CSF.

CONCLUSIONS

Compared to both controls and the MH(-) state, CSF Na(+) concentration increased in MH(+) independently from other clinical or pharmacological fluctuations, CSF concentrations of Ca(2+), Mg, and K(+), and blood plasma Na(+) levels. These results implicate a deviation of Na(+) homeostasis in migraine. The modestly elevated extracellular Na(+) in MH(+) may cause the neural changes that underlie clinical features of migraine.

NF-kappaB activity and iNOS expression in monocytes from internal jugular blood of migraine without aura patients during attacks

This study investigated nuclear factor-kappa B (NF-kappaB) activity by electrophoresis mobility gel shift assay and IkappaBalpha expression by Western blot analysis in monocytes obtained from serial samples of internal jugular venous blood taken from seven migraine patients without aura during attacks. Inducible nitric oxide synthase (iNOS) expression was also assessed by reverse transcription-polymerase chain reaction. An increase in NF-kappaB activity peaked 2 h after attack onset. This was accompanied by a transient reduction in IkappaBalpha expression. Up-regulation of iNOS was evident at 4 h, maintained at 6 h and reduced at the end of the attack. These findings substantiate the hypothesis of transitory delayed inflammation, as suggested by the animal model, and suggest the possibility of using therapeutic approaches to target NF-kappaB transcription in the treatment of migraine.

Retinal Vascular Caliber and Migraine: The Blue Mountains Eye Study

OBJECTIVE

To assess whether migraine is associated with retinal microvascular caliber.

BACKGROUND

Migraine is believed to be associated with vascular disease, but few studies have investigated the relationship between structural microvascular changes and migraine.

DESIGN

Population-based cross-sectional study.

METHODS

Participants in the Blue Mountains Eye Study follow-up (1997 to 1999, n = 2,335, aged 54+) had retinal photographs taken. A computer-assisted method was used to measure average retinal arteriolar and venular diameters and calculate the arteriole-to-venule ratio. History of migraine was recorded by interview using International Headache Society criteria (1988).

RESULTS

Subjects giving a history of migraine without aura (n = 128) had narrower retinal arterioles than subjects giving a history of migraine with aura (n = 182) or subjects with no migraine history (n = 1619). After multivariate adjustment, mean retinal arteriolar diameter was 4.3 microm (95% confidence interval 0.5, 8.1) narrower in subjects reporting migraine without aura as compared to subjects with no migraine.

CONCLUSIONS

Individuals with a history of migraine without aura were more likely to have slightly narrower retinal arteriolar caliber than individuals without migraine. This relationship was not present for migraine with aura. These data support the hypothesis that microvascular disease may be associated with certain types of migraine.

The Linear Behavior of the System Middle Cerebral Artery Flow Velocity and Blood Pressure in Patients With Migraine

BACKGROUND AND PURPOSE

Migraine is considered a disorder of the autonomic nervous system. We used the frequency analysis of dynamic cerebral autoregulation to assess whether blood flow regulation disturbances can be found at the frequencies at which sympathetic and parasympathetic activity is present.

METHODS

We measured simultaneously mean arterial blood pressure (BP) and the mean blood velocity (V) in the middle cerebral artery using transcranial Doppler ultrasound in 33 healthy controls (mean age+/-SD; 36+/-13 years) and in 22 patients with migraine (mean age; 39+/-7 years). Apart from assessing spectral power density for BP and V, we calculated the transfer function parameters gain, phase, and coherence at the frequency range between 0.0 and 0.25 Hz.

RESULTS

Compared with the controls, the spectral power density of BP and V exhibited a maximum magnitude of 10(26) in the migraine patients, whereas the maximum magnitude of BP and V in the controls was 10(-3). Coherence showed no difference between patients and controls. Gain between BP and V increased in the controls >0.01 Hz but was approximately 0 or negative in the migraine patients over the whole frequency range (P<0.01). The usually observed phase lead of V against BP was absent in the migraine patients in whom BP leaded V over nearly the whole frequency range (P<0.01).

CONCLUSIONS

In terms of phase and gain, dynamic cerebral autoregulation is completely different in migraine patients compared with healthy subjects. Insofar, this can be interpreted as a lack of sympathetic and parasympathetic control of cerebral blood flow.

Functional 1H-MRS findings in migraine patients with and without aura assessed interictally

The present study was aimed at investigating changes in brain metabolites due to visual cortex activation in migraineurs and normal subjects by (1)H-magnetic resonance spectroscopy (MRS). Twenty-two migraine patients with aura, 22 migraine patients without aura, and 10 control subjects were assessed. The volume of interest (about 8 cm(3)) was placed on the visual cortex area and the visual stimulus was applied using MR-compatible goggles with a flashing red light at a frequency of 8 Hz and an intensity of 14 lx. Data were acquired over 36'40". The experimental time course was: baseline phase, from 0 to 3'40" (1 spectrum); on phase (flashing light condition), from 3'40" to 29'20" (1540") (7 spectra), and off phase, from 29'20" to the end of the experiment at 36'40" (2 spectra). The main result of photic stimulation in patients with migraine with aura is the more consistent decrease (-14.61%) of the N-acetylaspartate (NAA) signal, which is significantly greater than that found in migraine patients without aura and control subjects. A parallel slight increase in the lactate peak was also detected. The above findings support little differences in brain metabolites between the two patient groups assessed in interictal periods, which suggests a less efficient mitochondrial functioning in migraine with aura patients.

The contribution of functional neuroimaging to primary headaches

Functional imaging techniques have begun to provide considerable insight into the pathophysiology of primary headache syndromes. PET and f-MRI have allowed to to monitor the physiological cortical reaction and nociceptor transmission of head-pain, but more importantly have identified pathophysiological abnormalities and even the "motor" in migraine and cluster headache attacks. This has even prompted new treatment options such as DBS in cluster headache and will undoubtly change the way we see headache. Innovative techniques such as voxel- and deformation-based morphometry have just started to unravel the structural consequences of chronic pain. Functional imaging will undoubtedly provide further opportunities to study and compare metabolic, haemodynamic and structural parameters in headache sufferers' brains.

Functional neuroimaging of primary headache disorders

Until recently, primary headache disorders such as migraine and cluster headache were considered to be vascular in origin. However, advances in neuroimaging techniques, such as positron emission tomography, single photon emission computerized tomography, and functional magnetic resonance imaging, have augmented the growing clinical evidence that these headaches are primarily driven from the brain. This review covers functional imaging studies in migraine, cluster headache, rarer headache syndromes, and experimental head pain. Together with newer techniques, such as voxel-based morphometry and magnetic resonance spectrometry, functional imaging continues to play a role in elucidating and targeting the neural substrates in each of the primary headache syndromes.

Latent class and genetic analysis does not support migraine with aura and migraine without aura as separate entities

Latent class and genetic analyses were used to identify subgroups of migraine sufferers in a community sample of 6,265 Australian twins (55% female) aged 25-36 who had completed an interview based on International Headache Society (IHS) criteria. Consistent with prevalence rates from other population-based studies, 703 (20%) female and 250 (9%) male twins satisfied the IHS criteria for migraine without aura (MO), and of these, 432 (13%) female and 166 (6%) male twins satisfied the criteria for migraine with aura (MA) as indicated by visual symptoms. Latent class analysis (LCA) of IHS symptoms identified three major symptomatic classes, representing 1) a mild form of recurrent nonmigrainous headache, 2) a moderately severe form of migraine, typically without visual aura symptoms (although 40% of individuals in this class were positive for aura), and 3) a severe form of migraine typically with visual aura symptoms (although 24% of individuals were negative for aura). Using the LCA classification, many more individuals were considered affected to some degree than when using IHS criteria (35% vs. 13%). Furthermore, genetic model fitting indicated a greater genetic contribution to migraine using the LCA classification (heritability, h(2)=0.40; 95% CI, 0.29-0.46) compared with the IHS classification (h(2)=0.36; 95% CI, 0.22-0.42). Exploratory latent class modeling, fitting up to 10 classes, did not identify classes corresponding to either the IHS MO or MA classification. Our data indicate the existence of a continuum of severity, with MA more severe but not etiologically distinct from MO. In searching for predisposing genes, we should therefore expect to find some genes that may underlie all major recurrent headache subtypes, with modifying genetic or environmental factors that may lead to differential expression of the liability for migraine.

Contrasts in cortical magnesium, phospholipid and energy metabolism between migraine syndromes

BACKGROUND

Previous single voxel (31)P MRS pilot studies of migraine patients have suggested that disordered energy metabolism or Mg(2+) deficiencies may be responsible for hyperexcitability of neuronal tissue in migraine patients. These studies were extended to include multiple brain regions and larger numbers of patients by multislice (31)P MR spectroscopic imaging.

METHODS

Migraine with aura (MWA), migraine without aura (MwoA), and hemiplegic migraine patients were studied between attacks by (31)P MRS imaging using a 3-T scanner.

RESULTS

Results were compared with those in healthy control subjects without headache. In MwoA, consistent increases in phosphodiester concentration [PDE] were measured in most brain regions, with a trend toward increase in [Mg(2+)] in posterior brain. In MWA, phosphocreatine concentration ([PCr]) was decreased to a minor degree in anterior brain regions and a trend toward decreased [Mg(2+)] was observed in posterior slice 1, but no consistent changes were found in phosphomonoester concentration [PME], [PDE], inorganic phosphate concentration ([Pi]), or pH. In hemiplegic migraine patients, [PCr] had a tendency to be lower, and [Mg(2+)] was significantly lower than in the posterior brain regions of control subjects. Trend analysis showed a significant decrease of brain [Mg(2+)] and [PDE] in posterior brain regions with increasing severity of neurologic symptoms.

CONCLUSIONS

Overall, the results support no substantial or consistent abnormalities of energy metabolism, but it is hypothesized that disturbances in magnesium ion homeostasis may contribute to brain cortex hyperexcitability and the pathogenesis of migraine syndromes associated with neurologic symptoms. In contrast, migraine patients without a neurologic aura may exhibit compensatory changes in [Mg(2+)] and membrane phospholipids that counteract cortical excitability.

Valproic acid in prophylaxis of refractory migraine

OBJECTIVE

The efficacy and safety of valproic acid were assessed as a prophylactic agent in migraine patients who previously derived no significant benefit from conventional prophylactic medications for migraine.

PATIENTS AND METHODS

One hundred and twenty patients aged 23-58 years with the diagnosis of migraine without aura. Response to therapy was determined by using a headache calendar detailing the frequency and severity of attacks. Reduction of 50% or greater in the frequency or severity of headache was considered as improvement.

RESULTS

Improvement was observed in headache frequency within 67% of patients. Headache severity had been improved in 60% of patients. The mean average dosage of valproic acid was 1,250 mg daily. Most of the side effects are mild and tolerable.

CONCLUSION

These results suggest that valproic acid is effective and safe in the treatment of refractory migraine headache.