Motor and visual cortical excitability in migraineurs patients with or without aura: transcranial magnetic stimulation

Khedr, Eman M.; Ahmed, Mohamed A.; Mohamed, Khaled

doi:10.1016/j.neucli.2006.01.007

Cited by 64 publications

(54 citation statements)

References 30 publications

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“…Finally, PTs in migraine patients were not different from those of normal participants. This finding was similar to that reported by several authors (23)(24)(25)(26) but at variance with several others (15,17,(19)(20)(21)(22), we found no significant decrease of PT in migraineurs.…”

Section: Discussionsupporting

confidence: 93%

“…Studies with TMS of the occipital cortex have reported increased phosphene prevalence and/or thresholds particularly in migraine with aura (12,(14)(15)(16)(17)(18)(19)(20)(21)(22), suggesting therefore an increased excitability of cerebral cortex. By contrast, several authors reported opposite results (23)(24)(25)(26): lower phosphene prevalence in MA but no difference between controls and MO patients, and similar mean PT in individuals reporting phosphenes, which was confirmed in the present investigation.…”

Section: Discussionmentioning

confidence: 99%

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Correlation between habituation of visual-evoked potentials and magnetophosphene thresholds in migraine: A case-control study

et al. 2015

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Introduction: In migraine most studies report an interictal deficit of habituation of visual-evoked potentials (VEP-hab) and reduced thresholds for phosphene induction (PT) by transcranial magnetic stimulation (TMS). We searched for a possible correlation between VEP-hab and PT in migraine patients and healthy controls to test whether they reflect the same pathophysiological abnormality. Methods:We assessed PT and VEP-hab measured as the percentage change of N1/P1 amplitude over six blocks of 100 responses in 15 healthy volunteers (HV) and in 13 episodic migraineurs without aura (MO) between attacks. Results were compared using Mann-Whitney U test. Interrelationships were examined using Spearman's correlation. Results: In MO patients VEP-hab was reduced compared to HV (p ¼ 0.001), while PT were not significantly different between HV and MO. There was no correlation between PT and VEP-hab in either group of participants. Conclusions: We confirm that in interictal migraine VEP habituation is deficient, but magnetophosphene threshold normal. VEP-hab and PT were not correlated with each other in healthy controls or in migraineurs. This finding suggests that they index different facets of cortical excitability in migraine, i.e. a punctual normal measure of the cortical activation threshold for PT and a dynamic response pattern to repeated stimuli for VEP habituation.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Correlation between habituation of visual-evoked potentials and magnetophosphene thresholds in migraine: A case-control study

et al. 2015

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“…Occurrence of CNS hyperexcitability in migraine is also supported by neurophysiological studies employing transcranial magnetic stimulation (TMS) of occipital lobe [15] and measuring the resting motor threshold and silent period [16]. Further evidence of the hyperexcitability of brain in migraineurs is supported by 31 pNMR studies and pharmacological evidences employing lamotrigine.…”

Section: Glutamate and Auramentioning

confidence: 88%

Biochemistry of primary headaches: role of tyrosine and tryptophan metabolism

D’Andrea¹,

Cevoli

Colavito³

et al. 2015

Neurol Sci

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The pathogenesis of migraine as well as cluster headache (CH) is yet a debated question. In this review, we discuss the possible role of the of tyrosine and tryptophan metabolism in the pathogenesis of these primary headaches. These include the abnormalities in the synthesis of neurotransmitters: high level of DA, low level of NE and very elevated levels of octopamine and synephrine (neuromodulators) in plasma of episodic migraine without aura and CH patients. We hypothesize that the imbalance between the levels of neurotransmitters and elusive amines synthesis is due to a metabolic shift directing tyrosine toward an increased decarboxylase and reduced hydroxylase enzyme activities. The metabolic shift of the tyrosine is favored by a state of neuronal hyperexcitability and a reduced mitochondrial activity present in migraine. In addition we present biochemical studies performed in chronic migraine and chronic tension-type headache patients to verify if the same anomalies of the tyrosine and tryptophan metabolism are present in these primary headaches and, if so, their possible role in the chronicity process of CM and CTTH. The results show that important abnormalities of tyrosine metabolism are present only in CM patients (very high plasma levels of DA, NE and tryptamine). Tryptamine plasma levels were found significantly lower in both CM and CTTH patients. In view of this, we propose that migraine and, possibly, CH attacks derive from neurotransmitter and neuromodulator metabolic abnormalities in a hyperexcitable and hypoenergetic brain that spread from the frontal lobe, downstream, resulting in abnormally activated nuclei of the pain matrix. The low tryptamine plasma levels found in CM and CTTH patients suggest that these two primary chronic headaches are characterized by a common insufficient serotoninergic control of the pain threshold.

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“…The neurophysiological assessment of cortical excitability was performed in patients and healthy volunteers using TMS, as previously published by our group in other clinical conditions [16][17][18][19][20][21][22]. The studied parameters consisted of: resting and active motor thresholds (RMT and AMT), cortical silent period (CSP), transcallosal inhibition (TCI), short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF).…”

Section: Neurophysiological Assessmentmentioning

confidence: 99%

“…This deficient inhibition is thought to have a neurophysiological signature that is an increased level of cortical excitability [25,33]. In a number of studies of our group, transcranial magnetic stimulation (TMS) of motor cortex has been used to evaluate both cortical facilitatory and inhibitory mechanisms in different groups of patients [16][17][18][19][20][21][22]. In OCD a recent meta-analysis [31] was published and concluded that there is deficient cortical inhibition in OCD.…”

Section: Introductionmentioning

confidence: 99%

Motor cortical excitability in obsessive-compulsive disorder: Transcranial magnetic stimulation study

Khedr

Elbeh

Elserogy

et al. 2016

Neurophysiologie Clinique/Clinical Neurophysiology

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Motor and visual cortical excitability in migraineurs patients with or without aura: transcranial magnetic stimulation

Cited by 64 publications

References 30 publications

Correlation between habituation of visual-evoked potentials and magnetophosphene thresholds in migraine: A case-control study

Correlation between habituation of visual-evoked potentials and magnetophosphene thresholds in migraine: A case-control study

Biochemistry of primary headaches: role of tyrosine and tryptophan metabolism

Motor cortical excitability in obsessive-compulsive disorder: Transcranial magnetic stimulation study

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