Framingham Risk Stratification of Middle-Aged Migraineurs.

Introduction. Migraine is a common primary headache disorder involving about 10-15% of the whole population. Several epidemiological and prospective studies showed a link between migraine (especially migraine with aura) and cardio- and cerebrovascular events. OBJECTIVES: We prospectively analyzed the data of vascular event-free middle-aged patients with migraine who were referred to our Headache Clinic between 01/2014 and 01/2018. Framingham 10-year risk were calculated; covariates included in the analysis were age, total cholesterol, HDL cholesterol, systolic blood pressure, antihypertensive medication use, current smoking, and diabetes status. RESULTS: Total of 1037 patients were screened and 221 were selected, 161 were women (mean age 55.5 ± 5.2 years) and 60 were men (mean age 56 ± 6 years). 25 patients (11.3%) were labelled as having low risk, 162 patients (73.3%) had moderate risk, and 34 patients (15.4%) had high or very high risk. Blood pressure and lipid targets were reached in 73% and in 49% in the moderate risk and in 53% and 12% in the high risk/very high risk groups, respectively. Migraine with aura (MA) was associated significantly higher cardiovascular risk profile compared with migraine without aura (MO). About one-third of our nondiabetic patients had fasting blood glucose above the normal levels. 24 patients (mean age 60 ± 4.9 years) were diabetic. Mean blood pressure was 149/85 Hgmm, mean choleterol was 5.11 mmol/l, and mean LDL was 2.93 mmol/l in this subgroup, respectively, which do not fall within the recommended targets. CONCLUSION: Our article draws attention to the higher cardiovascular risk profile of middle-aged migraineurs and highlights the deficiency of primary prevention. Pain physicians must be aware of the cardiovascular aspects of migraine and holistic approach is required instead of focusing only on pain and pain relief.

The American Registry for Migraine Research: Research Methods and Baseline Data for an Initial Patient Cohort.

BACKGROUND: The American Registry for Migraine Research (ARMR) is a multicenter, prospective, longitudinal patient registry, biorepository, and neuroimaging repository that collects clinical data, electronic health record (EHR) data, blood samples, and brain imaging data from individuals with migraine or other headache types. In this manuscript, we outline ARMR research methods and report baseline data describing an initial cohort of ARMR participants. METHODS: Adults with any International Classification of Headache Disorders (ICHD) diagnosis were prospectively enrolled from one of the 8 participating headache specialty centers. At baseline, ARMR participants complete web-based questionnaires, clinicians enter the participant's ICHD diagnoses, an optional blood specimen is collected, and neuroimaging data are uploaded to the ARMR neuroimaging repository. Participants maintain the ARMR daily headache diary longitudinally and follow-up questionnaires are completed by participants every 3 months. EHR data are integrated into the ARMR database from a subset of ARMR sites. Herein, we describe the ARMR methodology and report the summary data from ARMR participants who had, from February 2016 to May 2019, completed at least 1 baseline questionnaire from which data are reported in this manuscript. Descriptive statistics are used to provide an overview of patient's sociodemographics, headache diagnoses, headache characteristics, most bothersome symptoms other than headache, headache-related disability, comorbidities, and treatments. RESULTS: Data were available from 996 ARMR participants, enrolled from Mayo Clinic Arizona, Dartmouth-Hitchcock Medical Center, University of Utah, University of Colorado, Thomas Jefferson University, University of Texas Health Science Center at Houston, Georgetown University Medical Center, and DENT Neurological Institute. Among ARMR participants, 86.7% (n = 864) were female and the mean age at the time of enrollment was 48.6 years (±13.9; range 18-84). The most common provider-reported diagnosis was chronic migraine (n = 622), followed by migraine without aura (n = 327), migraine with aura (n = 196), and medication overuse headache (n = 65). Average headache frequency was 19.1 ± 9.2 days per month (n = 751), with 68% reporting at least 15 headache days per month. Sensitivity to light was the most frequent (n = 222) most bothersome symptom overall, other than headache, but when present, cognitive dysfunction was most frequently (n = 157) the most bothersome symptom other than headache. Average migraine disability assessment (MIDAS) score was 52 ± 49 (n = 760), (very severe headache-related disability); however, 17% of the ARMR population had MIDAS scores suggesting "no" or "mild" disability. The most common non-headache health issues were allergies (n = 364), back pain (n = 296), neck pain (n = 296), depression (n = 292), and anxiety (n = 278). Nearly 85% (n = 695) of patients were using preventive medications and 24.7% were using non-medication preventive therapy (eg, vitamins and neuromodulation). The most common preventive medication classes were neurotoxins, anticonvulsants, antidepressants, vitamins/supplements, and anticalcitonin gene-related peptide ligand or receptor-targeted monoclonal antibodies. Nearly 90% (n = 734) of ARMR participants was taking medications to treat migraine attacks, with the most common classes being triptans, non-steroidal anti-inflammatory drugs, antiemetics, acetaminophen, and combination analgesics. CONCLUSIONS: ARMR is a source of real-world patient data, biospecimens, and brain neuroimaging data that provides comprehensive insight into patients with migraine and other headache types being seen in headache specialty clinics in the United States. ARMR data will allow for longitudinal and advanced analytics that are expected to lead to a better characterization of patient heterogeneity, healthcare resource utilization, identification of endophenotypes, factors that predict treatment outcomes and clinical course, and ultimately advance the field toward precision headache medicine.

Enhanced Thalamocortical Synaptic Transmission and Dysregulation of the Excitatory-Inhibitory Balance at the Thalamocortical Feedforward Inhibitory Microcircuit in a Genetic Mouse Model of Migraine.

Migraine is a complex brain disorder, characterized by attacks of unilateral headache and global dysfunction in multisensory information processing, whose underlying cellular and circuit mechanisms remain unknown. The finding of enhanced excitatory, but unaltered inhibitory, neurotransmission at intracortical synapses in mouse models of familial hemiplegic migraine (FHM) suggested the hypothesis that dysregulation of the excitatory-inhibitory balance in specific circuits is a key pathogenic mechanism. Here, we investigated the thalamocortical (TC) feedforward inhibitory microcircuit in FHM1 mice of both sexes carrying a gain-of-function mutation in CaV2.1. We show that TC synaptic transmission in somatosensory cortex is enhanced in FHM1 mice. Due to similar gain of function of TC excitation of layer 4 excitatory and fast-spiking inhibitory neurons elicited by single thalamic stimulations, neither the excitatory-inhibitory balance nor the integration time window set by the TC feedforward inhibitory microcircuit was altered in FHM1 mice. However, during repetitive thalamic stimulation, the typical shift of the excitatory-inhibitory balance toward excitation and the widening of the integration time window were both smaller in FHM1 compared with WT mice, revealing a dysregulation of the excitatory-inhibitory balance, whereby the balance is relatively skewed toward inhibition. This is due to an unexpected differential effect of the FHM1 mutation on short-term synaptic plasticity at TC synapses on cortical excitatory and fast-spiking inhibitory neurons. Our findings point to enhanced transmission of sensory, including trigeminovascular nociceptive, signals from thalamic nuclei to cortex and TC excitatory-inhibitory imbalance as mechanisms that may contribute to headache, increased sensory gain, and sensory processing dysfunctions in migraine.SIGNIFICANCE STATEMENT Migraine is a complex brain disorder, characterized by attacks of unilateral headache and by global dysfunction in multisensory information processing, whose underlying cellular and circuit mechanisms remain unknown. Here we provide insights into these mechanisms by investigating thalamocortical (TC) synaptic transmission and the function of the TC feedforward inhibitory microcircuit in a mouse model of a rare monogenic migraine. This microcircuit is critical for gating information flow to cortex and for sensory processing. We reveal increased TC transmission and dysregulation of the cortical excitatory-inhibitory balance set by the TC feedforward inhibitory microcircuit, whereby the balance is relatively skewed toward inhibition during repetitive thalamic activity. These alterations may contribute to headache, increased sensory gain, and sensory processing dysfunctions in migraine.

Advanced visual network and cerebellar hyperresponsiveness to trigeminal nociception in migraine with aura.

BACKGROUND: Despite the growing body of advanced studies investigating the neuronal correlates of pain processing in patients with migraine without aura (MwoA), only few similar studies have been conducted in patients with migraine with aura (MwA). Therefore, we aimed to explore the functional brain response to trigeminal noxious heat stimulation in patients with MwA. METHODS: Seventeen patients with MwA and 15 age- and sex-matched healthy controls (HC) underwent whole-brain blood oxygen level-dependent (BOLD) fMRI during trigeminal noxious heat stimulation. To examine the specificity of any observed differences between patients with MwA and HC, the functional response of neural pathways to trigeminal noxious heat stimulation in patients with MwA was compared with 18 patients with MwoA. Secondary analyses investigated the correlations between BOLD signal changes and clinical parameters of migraine severity. RESULTS: We observed a robust cortical and subcortical pattern of BOLD response to trigeminal noxious heat stimulation across all participants. Patients with MwA showed a significantly increased activity in higher cortical areas known to be part of a distributed network involved in advanced visual processing, including lingual gyrus, inferior parietal lobule, inferior frontal gyrus and medial frontal gyrus. Moreover, a significantly greater cerebellar activation was observed in patients with MwA when compared with both patients with MwA and HC. Interestingly, no correlations were found between migraine severity parameters and magnitude of BOLD response in patients with MwA. CONCLUSION: Our findings, characterized by abnormal visual pathway response to trigeminal noxious heat stimulation, support the role of a functional integration between visual and trigeminal pain networks in the pathophysiological mechanisms underlying migraine with aura. Moreover, they expand the concept of "neurolimbic-pain network" as a model of MwoA including both limbic dysfunction and cortical dys-excitability. Indeed, we suggest a model of "neurolimbic-visual-pain network" in MwA patients, characterized by dysfunctional correlations between pain-modulating circuits not only with the cortical limbic areas but with advanced visual areas as well. Furthermore, the abnormal cerebellar response to trigeminal noxious heat stimulation may suggest a dysfunctional cerebellar inhibitory control on thalamic sensory gating, impinging on the advanced visual processing cortical areas in patients with MwA.

Current understanding of cortical structure and function in migraine.

OBJECTIVE: To review and discuss the literature on the role of cortical structure and function in migraine. DISCUSSION: Structural and functional findings suggest that changes in cortical morphology and function contribute to migraine susceptibility by modulating dynamic interactions across cortical and subcortical networks. The involvement of the cortex in migraine is well established for the aura phase with the underlying phenomenon of cortical spreading depolarization, while increasing evidence suggests an important role for the cortex in perception of head pain and associated sensations. As part of trigeminovascular pain and sensory processing networks, cortical dysfunction is likely to also affect initiation of attacks. CONCLUSION: Morphological and functional changes identified across cortical regions are likely to contribute to initiation, cyclic recurrence and chronification of migraine. Future studies are needed to address underlying mechanisms, including interactions between cortical and subcortical regions and effects of internal (e.g. genetics, gender) and external (e.g. sensory inputs, stress) modifying factors, as well as possible clinical and therapeutic implications.

Alpha-Lipoic Acid Shows Promise to Improve Migraine in Patients with Insulin Resistance: A 6-Month Exploratory Study.

Alpha-lipoic acid (ALA) is known to lower insulin resistance (IR), which is common among migraineurs. To assess the effect of ALA on headache in migraineurs with IR, we performed an exploratory study on a cohort of patients with migraine, followed at our Headache Center. The 32 patients took ALA 400 mg b.i.d. for 6 months in addition to their on-going treatment. The percentage of patients with a reduction of at least 50% of the attacks was 0.53 (confidence interval [95% CI] 0.36-0.70) at 2 months, 0.56 (0.39-0.73) at 4 months, and 0.69 (0.53-0.85) at 6 months. The incidence rate ratio of attacks at 6 months versus baseline was 0.48 (0.43-0.53, P < .001), corresponding to a mean (95% CI) number of attacks of 5 (4-6) versus 11 (10-12). The number of days of treatment in the previous month was 7.7 (6.8-8.7) at baseline, 5.4 (4.6-6.2) at 2 months, 5.3 (4.5-6.1) at 4 months, and 4.3 (3.6-5.0) at 6 months. Baseline and 120-min glucose and insulin and quantitative insulin sensitivity check index (QUICKI) and the Stumvoll index did not change at 6 months versus baseline. This exploratory study shows that the administration of ALA may be associated with a reduction in the number of attacks and the days of treatment in migraineurs with IR. A randomized controlled trial is needed to test this possibility.

Enhanced susceptibility to cortical spreading depression in two types of Na+,K+-ATPase α2 subunit-deficient mice as a model of familial hemiplegic migraine 2.

Background Patients with familial hemiplegic migraine type 2 (FHM2) have a mutated ATP1A2 gene (encoding Na+,K+-ATPase α2 subunit) and show prolonged migraine aura. Cortical spreading depression (CSD), which involves mass depolarization of neurons and astrocytes that propagates slowly through the gray matter, is profoundly related to aura. Methods In two types of Atp1a2-defective heterozygous mice, Atp1a2tm1Kwk (C-KO) and Atp1a2tm2Kwk (N-KO), the sensitivity and responsiveness to CSD were examined under urethane anesthesia. Results In both cases, heterozygotes exhibited a low threshold for induction of CSD, faster propagation rate, slower recovery from DC deflection, and profound suppression of the electroencephalogram, compared to wild-type mice. A high dose of KCl elicited repeated CSDs for a longer period, with a tendency for a greater frequency of CSD occurrence in heterozygotes. The difference of every endpoint was slightly greater in N-KO than C-KO. Change of regional cerebral blood flow in response to CSD showed no significant difference. Conclusion Heterozygotes of Atp1a2-defective mice simulating FHM2 demonstrated high susceptibility to CSD rather than cortical vasoreactivity, and these effects may differ depending upon the knockout strategy for the gene disruption. These results suggest that patients with FHM2 may exhibit high susceptibility to CSD, resulting in migraine.

Auditory Processing in Children with Migraine: A Controlled Study.

Background This study aimed to investigate central auditory processing performance in children with migraine and compared with controls without headache. Methods Twenty-eight children of both sexes, aged between 8 and 12 years, diagnosed with migraine with and without aura, and a control group of the same age range and with no headache history, were included. Gaps-in-noise (GIN), duration pattern test (DPT), synthetic sentence identification (SSI) test, and nonverbal dichotic test (NVDT) were used to assess central auditory processing performance. Results Children with migraine performed significantly worse in DPT, SSI test, and NVDT when compared with controls without headache; however, no significant differences were found in the GIN test. Conclusions Children with migraine demonstrate impairment in the physiologic mechanism of temporal processing and selective auditory attention. In our short communication, migraine could be related to impaired central auditory processing in children.

Comparative potency of sensory-induced brainstem activation to trigger spreading depression and seizures in the cortex of awake rats: Implications for the pathophysiology of migraine aura.

BACKGROUND: Migraine and epilepsy are highly co-morbid neurological disorders associated with episodic dysfunction of both cortical and subcortical networks. The study examined the interrelation between cortical spreading depression, the electrophysiological correlate of migraine aura and seizures triggered at cortical and brainstem levels by repeated sound stimulation in rats with acoustic hypersensitivity (reflex audiogenic epilepsy). METHOD: In awake, freely moving rats with innate audiogenic epilepsy, 25 episodes of running seizure (brainstem seizures) were induced by repeated sound stimulation. Spreading depression and seizures were recorded using implanted cortical electrodes. RESULTS: The first sound-induced brainstem seizures evoked neither spreading depression nor seizures in the cortex. With repetition, brainstem seizures began to be followed by a single cortical spreading depression wave and an epileptiform discharge. Spreading depression was more frequent an early cortical event than seizures: spreading depression appeared after 8.4 ± 1.0 repeated stimulations in 100% rats (n = 24) while cortical seizures were recorded after 12.9 ± 1.2 tests in 46% rats. Brainstem seizure triggered unilateral long-latency spreading depression. Bilateral short-latency cortical spreading depression was recorded only after intense cortical seizures. CONCLUSION: These data show that episodic brainstem activation is a potent trigger of unilateral cortical spreading depression. Development of intense seizures in the cortex leads to initiation of spreading depression in multiple cortical sites of both hemispheres.

Central auditory processing and migraine: a controlled study.

BACKGROUND: This study aimed to verify and compare central auditory processing (CAP) performance in migraine with and without aura patients and healthy controls. METHODS: Forty-one volunteers of both genders, aged between 18 and 40 years, diagnosed with migraine with and without aura by the criteria of "The International Classification of Headache Disorders" (ICDH-3 beta) and a control group of the same age range and with no headache history, were included. Gaps-in-noise (GIN), Duration Pattern test (DPT) and Dichotic Digits Test (DDT) tests were used to assess central auditory processing performance. RESULTS: The volunteers were divided into 3 groups: Migraine with aura (11), migraine without aura (15), and control group (15), matched by age and schooling. Subjects with aura and without aura performed significantly worse in GIN test for right ear (p = .006), for left ear (p = .005) and for DPT test (p < .001) when compared with controls without headache, however no significant differences were found in the DDT test for the right ear (p = .362) and for the left ear (p = .190). CONCLUSIONS: Subjects with migraine performed worsened in auditory gap detection, in the discrimination of short and long duration. They also presented impairment in the physiological mechanism of temporal processing, especially in temporal resolution and temporal ordering when compared with controls. Migraine could be related to an impaired central auditory processing. CLINICAL TRIAL REGISTRATION: Research Ethics Committee (CEP 0480.10) - UNIFESP.

Is the brain of migraineurs "different" even in dreams?

Migraineurs brain is hyper-excitable and hypo-metabolic. Dreaming is a mental state characterized by hallucinatory features in which imagery, emotion, motor skills and memory are created de novo. To evaluate dreams in different kinds of headache. We included 219 controls; 148 migraineurs (66 with aura-MA, 82 without aura-MO); 45 tension type headache (TTH) patients. ICHD-II diagnostic criteria were used. Ad hoc questionnaire was used to evaluate oneiric activity. The Generalized Anxiety Disorder Questionnaire, and the Patient Health Questionnaire were administered to evaluate anxiety and mood. The prevalence of dreamers was similar in different groups. Frequency of visual and auditory dreams was not different between groups. Migraineurs, particularly MA, had an increased frequency of taste dreams (present in 19.6 % of controls, 40.9 % of MA, 23.2 % of MO, 11.1 % of TTH, p < 0.01), and of olfactory dreams (present in 20 % of controls, 36 % of MA, 35 % of MO and 20 % of TTH, p < 0.01). Anxiety and mood did not influence these results. The increased frequency of taste and olfactory dreams among migraineurs seems to be specific, possibly reflecting a particular sensitivity of gustative and olfactory brain structures, as suggested by osmofobia and nausea, typical of migraine. This may suggest the role of some cerebral structures, such as amygdala and hypothalamus, which are known to be involved in migraine mechanisms as well in the biology of sleep and dreaming.

Occipital nerve stimulation for chronic migraine.

Occipital nerve stimulation may be effective in treating chronic migraine. Six studies, including three double-blind studies, were performed, with five showing evidence of benefit. However, of the three randomized, controlled trials, none has met a primary endpoint successfully. A separate study suggested a benefit for combined supraorbital and greater occipital nerve stimulation.

Alliaceous migraines.

OBJECTIVE: To report a migraineur with osmophobia and trigger to garlic and onion aroma. BACKGROUND: While odors serve as a trigger in 70% of migraineurs, alliaceous aromas have been described only rarely. Furthermore, nor has more than one type of alliaceous odor acted as a trigger in the same individual. Neither has migraine with aura been described as precipitated by such aromas. A patient experiencing migraines with aura, triggered almost exclusively by alliaceous aromas, is described. CASE STUDY: 32-year-old woman; 5 years previously felt nasal pruritis upon eating a red onion dip. Shortly thereafter, the mere aroma of raw onions caused a sensation of her throat closing along with an associated panic attack. Over the intervening years, upon exposure to onions and garlic aroma she experienced a fortification spectra and visual entopia, followed by a bipareital, crushing level 10/10 headache, burning eyes and nose, lacrimation, perioral paresthesias, generalized pruritis, nausea, fatigue, sore throat, dysarthria, confusion, dyspnea, palpitations, presyncopal sensations, hand spasms, tongue soreness, neck pain, phonophobia, and photophobia. These would persist for 1 hour after leaving the aroma. She was unresponsive to medication and would wear a surgical mask when out. The patient also experienced chemosensory complaints: dysosmias every few months; phantosmias of food or cleaning products every month for a minute of level 5/10 intensity; pallinosmia of onion or garlic odor for 30 minutes after exposure; and metallic pallinugeusia after eating with metal utensils. RESULTS: Neurological exam normal except for bilateral positive Hoffman reflexes. CHEMOSENSORY TESTING: Quick Smell Identification Test 3/3 and Brief Smell Identification Test 12/12 were normal. Magnetic resonance imaging and computed tomography with and without contrast normal. Allergy skin test was positive for garlic and onion. Nose plug and counter stimulation with peppermint prevented the onset of headaches and associated symptoms. CONCLUSION: This is the first report of migraines with aura triggered by more than one alliaceous compound in the same individual. Possible mechanisms include odor induced, emotional change, vasomotor instability, trigeminal-induced neurogenic inflammation, and allergic response. In alliaceous and odor-induced migraines, a trial of counter stimulation and nose plugs is warranted.

Impaired glutamatergic neurotransmission in migraine with aura? Evidence by an input-output curves transcranial magnetic stimulation study.

OBJECTIVE: An imbalance between activity of inhibitory and facilitatory intracortical circuits could play a central role in migraine etiology. We used input-output curves to achieve further information about intracortical excitability of motor cortex in migraine with aura. METHODS: Input-output curves were measured in the right abductor pollicis brevis muscle at rest in 12 patients suffering from migraine with aura and 8 healthy subjects. Stimuli were delivered at intensity ranging from 100% to 160% of resting motor threshold with 10-second inter-stimulus intervals. Seven patients were studied before and during treatment with levetiracetam. RESULTS: Results showed a greater motor-evoked potential amplitude in response to increasing intensity of stimuli in patients compared to controls (P < .02). This increased facilitatory effect was abolished by levetiracetam (P < .005). CONCLUSIONS: Our findings support the hypothesis of an interictal cortical hyper-responsivity in migraine patients that appears to be normalized by levetiracetam. This effect could support the potential therapeutic role of levetiracetam in migraine with aura prevention.

Effects of an estrogen-free, desogestrel-containing oral contraceptive in women with migraine with aura: a prospective diary-based pilot study.

BACKGROUND: Migraine with aura (MA) is a contraindication to the use of combined oral contraceptives (COCs) because of the increased risk of ischemic stroke. Progestogen-only contraceptive pill (POP) is a safe alternative to COCs and it is preferable in women with cerebrovascular diseases or risk factors for stroke. STUDY DESIGN: Prospective diary-based pilot study. Thirty women with MA (n = 15 who have never used COCs and n = 15 who had previously used COCs were diagnosed according to the International Headache Society criteria. The observational period lasted 9 months during which women filled in a diary with the clinical characteristics of headache attacks. After a 3-month run-in period, each subject received an estrogen-free desogestrel (DSG) (75 mcg/day)-containing OC (Cerazette(®); Schering-Plough, formerly NV Organon, Oss, The Netherlands). Follow-up evaluations were planned at the end of the third and sixth month of treatment. RESULTS: The number (mean±S.D.) of migraine attacks was significantly reduced both in previous COCs users (from 3.9±1.0 to 2.9±0.8; p<.001) and nonusers (from 3.2±0.9 to 2.6±1.3; p<.02) following 6 months of POP use in comparison with the run-in period. Duration of headache pain did not differ significantly in both groups throughout the study. Interestingly enough, a beneficial POP effect on the duration (mean±S.D.) of visual aura (from 16.3±9.5 to 11.4±5.6 min) and on the total duration (mean±S.D.) of neurological symptoms (from 33.6±23.3 to 18.6±18.0 min) was only significantly reported by previous COCs users (p<.001, for both) by the end of the study period. The POP was well tolerated by each woman and the bleeding pattern was variable with a tendency towards infrequent bleeding. CONCLUSIONS: The present study supports the use of the POP containing desogestrel in a population of women with MA and underlines a positive effect on symptoms of aura, especially in MA sensitive to previous use of COCs.

Unilateral cortical spreading depression induced by sound in rats.

Cortical spreading depression (SD) is thought to underlie the migraine aura but the mechanisms of triggering SD in the human cortex remain unknown. Because growing evidence points to a key role of brainstem circuits in initiating migraine attacks, the present study examined whether recurrent episodes of brainstem activation in rats could induce cortical SD. Explosive running elicited by sounds in rodents with inherited hypersensitivity to acoustic stimuli (reflex audiogenic epilepsy), is known to reflect a transient aberrant activation of the brainstem. Repeated induction of such audiogenic responses enhances the excitability of the cortex, culminating in its epileptic activation (audiogenic kindling). In Wistar rats with inherited hypersensitivity to sounds, 15 brief episodes of running were induced by sound stimulation, and slow potential shifts as well as the EEG were recorded in the cortex. Single unilateral SD began to occur in the cortex following a running episode after the 5th to 15th test (mean 9.4+/-1.2). Once appeared, SD was regularly recorded in subsequent tests. The side of the SD initiation closely correlated with the direction of running. Triggering SD was not associated with epileptic activation of the cortex in most rats. The present findings suggest that the sensory-induced brainstem excitation could be a potent trigger of SD in the hyperexcitable cortex, providing an experimental evidence of a possible causative role of the brainstem activation in initiating the migraine aura.

Somatosensory evoked high-frequency oscillations reflecting thalamo-cortical activity are decreased in migraine patients between attacks.

A deficit of habituation in cortical information processing, including somatosensory evoked potentials (SSEPs), is the most consistent neurophysiological abnormality in migraine patients between attacks. To explore further the mechanisms underlying this interictal neural dysfunction, we have studied the high-frequency oscillations (HFOs) embedded in SSEPs because they are thought to reflect spike activity in thalamo-cortical cholinergic fibres (early HFOs) and in cortical inhibitory GABAergic interneurons (late HFOs). Untreated migraine patients with (MA) and without (MO) aura were recorded during (n = 13: nine MO, four MA) and between attacks (n = 29: 14 MO, 15 MA) and compared with healthy volunteers. SSEPs were filtered off-line (digital band-pass between 450 and 750 Hz) to extract the two HFO bursts from the broad-band contralateral N20 somatosensory cortical response obtained by median nerve stimulation. In both migraine groups, amplitudes and latencies of conventional broad-band SSEPs recorded interictally from cervical and parietal active electrodes were not significantly different from those found in healthy volunteers. In contrast, maximum peak-to-peak amplitude and area under the rectified curve of the early HFO burst were significantly smaller in both MA and MO patients than in healthy volunteers. There was no significant difference in the later HFO burst between migraineurs and healthy volunteers. During attacks, all electrophysiological measurements in migraineurs were similar to those found in healthy volunteers. Thalamo-cortical activation, as reflected by the early SSEP HFO burst, may thus be reduced in migraine interictally, but normalizes during an attack, whereas intracortical inhibition, as indexed by the late HFO burst, is normal at any time. This supports the hypothesis that the habituation deficit in migraineurs is due to a reduced pre-activation level of sensory cortices and not to increased cortical excitability or reduced intracortical inhibition.

Biofeedback-assisted relaxation in migraine headache: relationship to cerebral blood flow velocity in the middle cerebral artery.

OBJECTIVE: To determine if migraineurs with aura respond differently to biofeedback/relaxation than those without aura and, if so, whether the variability in outcome can be explained by blood flow velocity. Background.-The relationship between cerebral blood flow velocity and treatment response to biofeedback/relaxation in migraine with and without aura is uncertain. METHOD: Twenty migraineurs underwent 12 sessions of biofeedback/relaxation therapy, while 20 controls simply were told to relax on their own. Cerebral blood flow velocity was measured bilaterally in the middle cerebral artery with transcranial Doppler. RESULTS: The biofeedback group showed significant (P <.05) reductions in pain, depression, and anxiety compared to the control group. Patients with and without aura did equally well. There were significant (P <.05) left to right blood flow velocity differences only in the migraine with aura group. Maximum blood flow velocities were significantly higher (P <.05) in the migraine with aura group than in the cohort without aura. There was an inverse correlation between indicators of anxiety and blood flow velocity, perhaps related to hyperventilation-induced constriction in the small vessels distal to the middle cerebral artery. CONCLUSION: The positive treatment response to biofeedback/relaxation in migraine headache is not related to presence of aura, nor to changes in blood flow velocity, but may be associated with reduction in anxiety and depression.

Comparison of visual and auditory evoked cortical potentials in migraine patients between attacks.

OBJECTIVE: As both habituation of pattern reversal visual evoked potentials (PR-VEP) (Schoenen J, Wang W, Albert A, Delwaide PJ. Potentiation instead of habituation characterizes visual evoked potentials in migraine patients between attacks. Eur J Neurol 1995;2:115-122) and intensity dependence of auditory evoked cortical potentials (IDAP) (Wang W, Timsit-Berthier M, Schoenen J. Intensity dependence of auditory evoked potentials in migraine: an indication of cortical potentiation and low serotonergic neurotransmission? Neurology 1996;46:1404-1409) were found abnormal in migraine between attacks, we have searched for intraindividual correlations between both tests in 59 migraine patients (22 with aura [MA], 37 without aura [MO]) and in 23 healthy volunteers (HV). METHODS: Amplitude change of the PR-VEP N1-P1 was measured between the 1st and 5th block of 50 sequential averagings during continuous stimulation at 3.1 Hz. IDAP was computed from N1-P2 amplitudes of 100 averagings during stimulations at 40, 50, 60 and 70 dB SL. Amplitude-stimulus intensity function (ASF) slopes and amplitude changes between 40 and 70 dB were calculated. MO and MA differed from HV in PR-VEP amplitude change (P=0.007) and IDAP slope (P = 0.0004). RESULTS: There was no significant correlation between VEP amplitude changes and IDAP slopes, nor between the latter two and attack frequency or disease duration. A negative correlation was found between the amplitude of the first block of averaged responses and potentiation of VEP in all subject groups (P = 0.03) as well as between the amplitude of the auditory evoked potential, at 40 dB, and the percentage of amplitude increase between 40 and 70 dB in MO (P = 0.004) and MA (P = 0.007). ASF slopes and 40 dB amplitudes were significantly correlated only in the MA group (P = 0.002). These results confirm the interictal deficit of habituation in cortical processing of repetitive visual and auditory information in migraine. Since there is no intraindividual correlation between the cortical responses to these sensory modalities they are complementary tools for the study of migraine and may help to identify subgroups of patients with distinct pathophysiological mechanisms. CONCLUSIONS: The strong negative correlation between the initial amplitude of evoked potentials and their amplitude increase during subsequent averaging confirms that the response potentiation in migraine is likely to be due to a reduced preactivation level of sensory cortices.