Chiara Lepre

Dynamic changes in thalamic microstructure of migraine without aura patients: a diffusion tensor magnetic resonance imaging study.

The thalamus seems to be profoundly involved in the cyclical recurrence of migraine clinical and neurophysiological features. Here possible structural changes in the thalamus of migraineurs were searched for by means of diffusion tensor (DT) magnetic resonance imaging (MRI). This MRI technique provides quantitative data on water molecule motion as a marker of tissue microstructure.

Evidence for brain morphometric changes during the migraine cycle: A magnetic resonance-based morphometry study

Neurophysiological investigations have demonstrated that there are unique fluctuations in the migraine brain functional activity between the ictal and interictal periods. Here we investigated the possibility that there are fluctuations over time also in whole brain morphometry of patients affected by episodic migraine without aura (MO). Twenty-four patients with untreated MO underwent 3T MRI scans during (n = 10) or between attacks (n = 14) and were compared to a group of 15 healthy volunteers (HVs). We then performed voxel-based-morphometry (VBM) analysis of structural T1-weighted MRI scans to determine if changes in brain structure were observed over the course of the migraine cycle. Interictally, MO patients had a significantly lower gray matter (GM) density within the right inferior parietal lobule, right temporal inferior gyrus, right superior temporal gyrus, and left temporal pole than did HVs. Ictally, GM density increased within the left temporal pole, bilateral insula, and right lenticular nuclei, but no areas exhibited decreased GM density. These morphometric GM changes between ictal and interictal phases suggest that abnormal structural plasticity may be an important mechanism of migraine pathology. Given the functional neuroanatomy of these areas, our findings suggest that migraine is a condition associated with global dysfunction of multisensory integration and memory processing.

Cortical response to somatosensory stimulation in medication overuse headache patients is influenced by angiotensin converting enzyme (ACE) I/D genetic polymorphism

Background Medication overuse headache (MOH) is a disabling health problem. Convincing evidence attributes a pathophysiologic role to central sensitization. By recording somatosensory evoked potentials (SSEPs) in patients with MOH, we observed increased sensitization and deficient habituation to repetitive sensory stimuli consistent with drug overuse. The renin–angiotensin system in the brain seems to play a relevant role in neural plasticity and dependence behavior. We therefore sought differences in SSEP sensitization and habituation in patients with MOH who underwent angiotensin converting enzyme (ACE) I/D polymorphism analysis. Methods We recorded median-nerve SSEPs (two blocks of 100 sweeps) in 43 patients with MOH. We measured N20–P25 amplitudes, and assessed sensitization using the first block amplitudes, and habituation using amplitude changes between the two sequential blocks. According to their genotype, subjects were divided into three groups: “D/D”, “D/I” and “I/I” carriers. Results The habituation slope of the two SSEP block amplitudes was significantly increased in the D/D subgroup (n = 16) with respect to that of the I/I subgroup (n = 6), with the D/I subgroup (n = 21) falling in between. In D/D carriers, the habituation slope correlated positively with the duration of the overuse headache, and the first SSEP block amplitudes, a measure of sensitization, increased in strict relationship with the type of overused medication in the MOH patients overall and in the D/D subgroup; this was not so in the D/I and I/I subgroups. Conclusion In patients with MOH, the homozygote D/D ACE polymorphism influences habituation and sensitization to repeated sensory stimuli in strict relationship with medication overuse. We suggest that angiotensin peptides influence neuronal mechanisms of plasticity by interacting with central monoaminergic synaptic transmission.

Recurrent leukoencephalopathy in a cocaine abuser

We report the case of a cocaine abuser who presented two consecutive episodes of acute leukoencephalopathy, documented by serial MRI, with favourable outcome. Clinical findings and brain imaging led to the diagnosis of cocaine-induced toxic leukoencephalopathy and other possible mimickers have been excluded on the basis of clinical assessment. The patients unexpected recovery on neurological and neuropsychological examination, despite initially severe neurological symptoms, is striking and differs from more common reports of a rapid progression to death. Of note, case presented in the peculiar form of recurrent episodes of acute leukoencephalopathy, with favourable outcome, which, to our knowledge, has not been described yet. We speculate about the aetiology of this condition, which is still poorly understood.

Influence of rTMS over the left primary motor cortex on initiation and performance of a simple movement executed with the contralateral arm in healthy volunteers

Repetitive transcranial magnetic stimulation (rTMS) affects cortical excitability according to the frequency of stimulation. Few data are available on the influence of rTMS applied over the primary motor cortex (M1) on motor performances in healthy volunteers. The aim of this study was to determine, through kinematic analysis, whether rTMS over the left M1 changes initiation and performance of movement executed with the contralateral arm. Nine healthy males completed a set of motor tasks, consisting of a single-joint rapid movement between two objects performed under three different behavioral conditions (self-initiated; externally triggered known, during which the subject could see where the target was positioned in advance; externally triggered unknown, during which the subject could not see where the target was positioned until he reached it). The tasks were performed in a randomized order in three different sessions, with a seven-day interval between each session: (1) without stimulation (baseline); (2) immediately after 1-Hz rTMS; (3) immediately after 10-Hz rTMS. We measured reaction time, movement time, calculated as the sum of the time taken to reach the target from movement onset (T1) and that taken to reach the target to movement termination (T2), acceleration and deceleration time on the velocity profile, as well as the ratio between them, and maximum speed and maximum acceleration. Reaction time, movement time, and T2 significantly increased after 1-Hz rTMS and decreased after 10-Hz rTMS, while the other parameters remained unchanged. Our results suggest that rTMS may modify both initiation and performance of a voluntary movement.

O028. Thalamo-cortical network changes during the migraine cycle: insights from MRI-based microstructural and functional resting-state network correlation analysis

O028. Thalamo-cortical network changes during the migraine cycle: insights from MRI-based microstructural and functional resting-state network correlation analysis Gianluca Coppola, Antonio Di Renzo, Emanuele Tinelli, Chiara Lepre, Elisa Iacovelli, Cherubino Di Lorenzo, Giorgio Di Lorenzo, Vincenzo Parisi, Mariano Serrao, Flavia Pauri, Giancarlo Fiermonte, Claudio Colonnese, Jean Schoenen, Francesco Pierelli

Short-term cortical synaptic depression/potentiation mechanisms in chronic migraine patients with or without medication overuse:

Objective To study the effects of trains of repetitive transcranial magnetic stimulation (rTMS) over the motor cortex in patients with chronic migraine (CM) with or without medication overuse (MOH). Subjects and methods Thirty-two patients (CM [n = 16]; MOH [n = 16]) and 16 healthy volunteers (HVs) underwent rTMS recording. Ten trains of 10 stimuli each (120% resting motor threshold) were applied over the left motor cortex at 1 Hz or 5 Hz in random order. The amplitude of motor evoked potential (MEP) was evaluated from electromyographic recording in the first dorsal interosseous muscle. The slope of the linear regression line for the 10 stimuli for each participant was calculated using normalized data. Results rTMS-1 Hz had a normal depressive effect on MEP amplitude in all groups. rTMS-5 Hz depressed instead of potentiating MEP amplitudes in MOH patients, with a significantly different response from that in HVs and CM patients. The slope of the linear regression of MEP amplitudes was negatively correlated with pain intensity in CM patients, and with the duration of overuse headache in MOH patients. Conclusions This different plastic behaviour suggests that MOH and CM, despite exhibiting a similar clinical phenotype, have different neurophysiological learning processes, probably related to different pathophysiological mechanisms of migraine chronification.

EHMTI-0177. Evidence for plastic brain morphometric changes during the migraine cycle

Background Neurophysiological investigations have demonstrated that there are distinctive fluctuations in the brain’ se lectric signals between the ictal and interictal periods of recurrent migraine. Whether structural plasticity of the brain is also an important feature of episodic migraine remains unresolved. Aim We therefore investigated the possibility that there are fluctuations over time in whole brain grey matter morphometry of patients affected by episodic migraine without aura (MO). Method Twenty-four patients with untreated MO underwent MRI scans (3-Tesla Siemens Verio) during (n = 10) or between attacks (n = 14) and were compared to a group of 15 healthy volunteers (HV). We then performed voxelbased-morphometry (VBM) analysis of structural T1-weighted MRI scans to determine if changes in brain structure were observed over the course of the migraine cycle. Results During the interictal phase, MO patients had a significantly lower grey matter (GM) density within the right inferior parietal lobule, right temporal inferior gyrus, right superior temporal gyrus, and left temporal pole than did HV. During attacks, GM density increased within the left temporal pole, bilateral insula, and right lenticular nuclei, but no areas exhibited decreased GM density. Conclusion The morphometric GM changes between ictal and interictal phases reported in the present study suggest that abnormal structural plasticity may be an important mechanism of migraine pathology. Given the functional neuroanatomy of these areas, our findings suggest that migraine is a condition associated with global dysfunction of multisensory integration and memory processing. No conflict of interest.

Altered thalamic microstructure in migraine without aura patients: a diffusion tensor magnetic resonance imaging study.

Background and objectives Studies of spontaneous EEG and visual or somatosensory evoked high frequency oscillations indicate that the abnormal fluctuations of cortical responsivity over time in relation to the migraine attack could be due to abnormal thalamic control. Here we searched for possible structural changes in the thalamus of migraineurs by mean of acquiring diffusion tensor magnetic resonance imaging (MRI). This MRI technique provides quantitative data on water molecular motion, as a marker of tissue structure. Materials & Method – Seventeen untreated migraine without aura (MO) patients underwent MRI scan (3-Tesla Siemens Gyroscan) during (n=7) and between attacks (n=10) and were compared to a group of 14 healthy volunteers (HV). We examined fractional anisotropy (FA) and mean diffusivity (MD) in the thalamus.