Comparison of cortical excitability in chronic migraine (transformed migraine) and migraine without aura

Abstract

We studied the excitability of the motor cortex in patients with migraine without aura (MWOA) (n = 20) and with chronic migraine (CM) (n = 20) using transcranial magnetic stimulation (TMS). By using a 90-mm circular coil placed over the vertex and recording of the first dorsal interosseous muscle, we measured thresholds, latencies and amplitudes of motor evoked potentials and duration of cortical silent periods in patient groups and in controls (n = 20). No differences were found between groups for threshold, latency and amplitude values. However, the duration of the cortical silent period was longer in CM patients, being significantly different from both controls and MWOA. We suggest that either this difference in cortical excitability may develop during transformation from MWOA to CM or different pathophysiological mechanisms may play a role in these two headache syndromes.

Motor and Occipital Cortex Excitability in Migraine Patients

“…Similarly, no interhemispheric difference between these parameters was noted. Our results support the studies 10,16 indicating that there is no hyperexcitability of motor cortex in migraine patients during interictal period.…”

“…Another two studies, however, showed no interictal changes of excitability of the motor cortex in migraine. 10,16 In our study performed during the interictal period, we did not find any significant difference in either MwA and MwoA patients compared with controls, in respect to the motor threshold, cortical MEP latencies and amplitudes, MEPmax/CMAPmax ratio and CMCT. Similarly, no interhemispheric difference between these parameters was noted.…”

“…Three different studies showed that the duration of CSP in migraine patients did not significantly differ from that of controls. 5,10,16 On the other hand, using low intensity magnetic stimulation, Aurora et al 8 found shortened CSP in MwA patients; but at maximal intensity levels of stimuli, this difference disappeared. In the light of these findings they suggested that there might be a dysfunction of GABAergic inhibitory interneurons depending on the level of stimulus intensity.…”

“…Motor symptoms in some migraine subtypes have also drawn attention to the hyperexcitability of motor cortex. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Transcranial magnetic stimulation (TMS) is a non-invasive tool to investigate physiology and excitability of both motor-and occipital cortices. 11,[21][22][23][24][25] The changes in motor threshold, latency and amplitude of motor evoked potential, central motor conduction time and cortical silent period after magnetic ABSTRACT: Objective: We evaluated motor and occipital cortex excitability in migraine patients using transcranial magnetic stimulation.…”

Neurophysiologische Befunde bei Migräne - Spiegelbild der Pathophysiologie oder Epiphänomen?

“…Diese zeigten nicht nur Abnormalitäten der extra-und intrazerebralen kraniellen Zirkulation während verschiedener Stadien einer Migräneat-tacke, sondern erlaubten darüber hinaus Rückschlüsse auf involvierte Strukturen und pathophysiologische Prozesse [15]. Messungen der regionalen zerebralen Perfusion während der Migrä-neaura, zunächst mithilfe der 133 Xenon-Perfusionsszintigraphie [16,17] und nachfolgende PET-Untersuchungen [18], demonstrierten dynamische, meist vom okzipitalen Kortex nach anterior wandernde Perfusionsminderungen (¹Spreading oligemiaª). Zeitlich und räumlich hochauflösende funktionelle MRT-Studien zur Messung des Blutflusses und der Oxygenierung (BOLD-MRT) aus jüngster Zeit ergaben darüber hinaus Anhaltspunkte für eine transiente kortikale Hyperperfusion im Initialstadium der Aura, die erst anschlieûend in eine Minuten bis wenige Stunden anhaltende kortikale Hypoperfusion übergeht und teilweise mit klinischen Zeichen kortikaler Stimulation (Szintillationen etc.)…”