Gabriel Möddel

Nerve fiber impairment of anterior thalamocortical circuitry in juvenile myoclonic epilepsy

Background: Juvenile myoclonic epilepsy (JME) is a syndrome of idiopathic generalized epilepsy (IGE) without structural brain abnormalities detectable by MRI or CT. Objective: In the present study, we addressed the question of whether diffusion tensor MRI (DTI) can detect disease-specific white matter (WM) abnormalities in patients with JME. Methods: We performed whole head DTI at 3 T in 10 patients with JME, 8 age-matched patients with cryptogenic partial epilepsy (CPE), and 67 age-matched healthy volunteers. Nerve fiber integrity was compared between the groups on the basis of optimized voxel-by-voxel statistics of fractional anisotropy (FA) maps obtained by DTI (analysis of covariance, categorical factor “group,” covariate “age”). Results: FA was reduced in a WM region associated with the anterior thalamus and prefrontal cortex in patients with JME compared to both control subjects and patients with CPE (p < 0.001). The patients with CPE showed normal values in this particular WM region. The FA reductions in the patients with JME correlated with the frequency of generalized tonic-clonic seizures (Spearman R = 0.54, p = 0.05). No significant correlations were found in the JME sample between FA reduction and the duration of antiepileptic medication. Conclusions: The results support the hypothesis that juvenile myoclonic epilepsy is associated with abnormalities of the thalamocortical network that can be detected by diffusion tensor MRI. CPE = cryptogenic partial epilepsy; DTI = diffusion tensor imaging; EPI = echoplanar imaging; FA = fractional anisotropy; GMC = gray matter concentration; GTCS = generalized tonic-clonic seizures; IGE = idiopathic generalized epilepsy; JME = juvenile myoclonic epilepsy; MNI = Montreal Neurological Institute; ROI = region of interest; VBM = voxel based morphometry; WM = white matter.

Complications during the Wada test

OBJECTIVE The intracarotid amobarbital procedure (IAP) is routinely used in the preoperative workup of patients with epilepsy. We previously reported dissections and seizures as complications of this procedure and now have reviewed our cohort for additional complications associated with the IAP. METHODS Charts of 677 consecutive patients were reviewed for complications during the IAP. RESULTS Complications were observed in 74 patients (10.9%) and included encephalopathy (7.2%), seizures (1.2%), strokes (0.6%), transient ischemic attacks (0.6%), localized hemorrhage at the catheter insertion site (0.6%), carotid artery dissections (0.4%), allergic reaction to contrast (0.3%), bleeding from the catheter insertion site (0.1%), and infection (0.1%). Older patients were more prone to strokes and dissections, whereas younger patients more frequently experienced seizures. Use of amobarbital was associated with encephalopathy, whereas methohexital was related to seizures. CONCLUSION The IAP bears the risk of minor and major complications in up to 11% of patients. Risks, benefits, and possible alternative options have to be considered when a patient is to undergo the IAP.

Frequency of seizures and epilepsy in neurological HIV-infected patients

BACKGROUND Infection with the human immunodeficiency virus (HIV) is associated both with infections of the central nervous system and with neurological deficits due to direct effects of the neurotropic virus. Seizures and epilepsy are not rare among HIV-infected patients. We investigated the frequency of acute seizures and epilepsy of patients in different stages of HIV infection. In addition, we compared the characteristics of patients who experienced provoked seizures only with those of patients who developed epilepsy. METHODS The database of the Department of Neurology, University of Münster, was searched for patients with HIV infection admitted between 1992 and 2004. Their charts were reviewed regarding all available sociodemographic, clinical, neurophysiological, imaging and laboratory data, therapy and outcome. Stage of infection according to the CDC classification and the epileptogenic zone were determined. RESULTS Of 831 HIV-infected patients treated in our department, 51 (6.1%) had seizures or epilepsy. Three of the 51 patients (6%) were diagnosed with epilepsy before the onset of the HIV infection. Fourteen patients (27%) only had single or few provoked seizures in the setting of acute cerebral disorders (eight patients), drug withdrawal or sleep withdrawal (two patients), or of unknown cause (four patients). Thirty-four patients (67%) developed epilepsy in the course of their HIV infection. Toxoplasmosis (seven patients), progressive multifocal leukencephalopathy (seven patients) and other acute or subacute cerebral infections (five patients) were the most frequent causes of seizures. EEG data of 38 patients were available. EEG showed generalized and diffuse slowing only in 9 patients, regional slowing in 14 patients and regional slowing and epileptiform discharges in 1 patient. Only 14 of the patients had normal EEG. At the last contact, the majority of the patients (46 patients=90%) were on highly active antiretroviral therapy (HAART). Twenty-seven patients (53%) were on anticonvulsant therapy (gabapentin: 14 patients, carbamazepine: 9 patients, valproate: 2 patients, phenytoin: 1 patient, lamotrigine: 1 patient). Patients with only provoked seizures had no epilepsy risk factors except HIV infection, and were less likely to be infected via intravenous drug abuse. CONCLUSIONS Seizures are a relevant neurological symptom during the course of HIV infection. Although in some patients seizures only occur provoked by acute disease processes, the majority of patients with new onset seizures eventually develops epilepsy and require anticonvulsant therapy. Intravenous drug abuse and the presence of non-HIV-associated risk factors for epilepsy seem to be associated with the development of chronic seizures in this patient group.

Altered Glutamate Receptor—Transporter Expression and Spontaneous Seizures in Rats Exposed to Methylazoxymethanol in Utero

Summary:  Purpose: Brain malformations are a common cause of intractable epilepsy and cognitive dysfunction in children. Prenatal exposure to the teratogen methylazoxymethanol (MAM) is a rodent model of brain malformation featuring loss of lamination, clusters of displaced hippocampal cells, and pharmaco‐resistance to antiepileptic drugs. In a normotopic hippocampus, expression of postsynaptic glutamate receptors and the transporters regulating neurotransmitter reuptake are critical factors modulating excitation and synaptic communication. Alterations in this system can have profound effects on overall excitability, cognitive function, and seizure thresholds.

Atypical Language Lateralization in Epilepsy Patients

Purpose:  To investigate whether atypical language dominance in epilepsy patients is related to localization and type of lesions.

Microstructural and volumetric abnormalities of the putamen in juvenile myoclonic epilepsy

Purpose:  Patients with juvenile myoclonic epilepsy (JME) show evidence of microstructural white matter (WM) damage of thalamocortical fiber tracts and changes of blood oxygen level dependent (BOLD) signal in a striatothalamocortical network. The objective of the present study was to investigate microstructural and volumetric alterations of the putamen in patients with JME using diffusion tensor imaging (DTI) and conventional magnetic resonance imaging (MRI).

Intravenous lacosamide—An effective add-on treatment of refractory status epilepticus

Status epilepticus (SE) is a frequent neurological emergency requiring immediate treatment. Therapy usually requires intravenous anticonvulsive medication. Lacosamide is a novel anticonvulsant drug that is available as infusion solution. We describe seven patients with focal SE who were treated with intravenous Lacosamide. All patients in our case series were unsuccessfully treated with other antiepileptic drugs before Lacosamide i.v. was added. In all cases, SE was terminated within 24 h after Lacosamide. There were no serious side effects or adverse events attributable to Lacosamide i.v. Our data suggest that Lacosamide might be an effective add-on treatment, if standard drugs fail or are unsuitable.

Gelastic seizures: A case of lateral frontal lobe epilepsy and review of the literature

We describe a 40-year-old patient with gelastic seizures triggered by hand movement. Despite nonlesional magnetic resonance imaging (MRI), electroencephalography (EEG), functional magnetic resonance imaging (fMRI), and diffusion tensor imaging (DTI) are concordant with seizure onset in the right frontocentral area. Seizure semiology and EEG recordings imply involvement of mesial frontal structures remote from seizure initiation site. We reviewed all published cases on gelastic seizures of frontal lobe origin to find characteristic features. For further investigation of the phenomenon of movement-induced seizures, fMRI was performed using a finger tapping paradigm. Interictal fMRI revealed widespread activation of right motor cortex during finger tapping on either side outreaching the anatomical representation of the left finger. In line with this finding DTI revealed fiber track impairment in the right frontocentral region, supporting the hypothesis of a focal derangement. This case highlights the importance of complementary functional investigations in MRI-negative epilepsies.

Voxel-Based Statistical Analysis of Fractional Anisotropy and Mean Diffusivity in Patients with Unilateral Temporal Lobe Epilepsy of Unknown Cause

To determine regional alterations of fractional anisotropy (FA) and mean diffusivity (MD) in patients with magnetic resonance imaging (MRI)‐negative temporal lobe epilepsy with unknown cause (TLEu) using diffusion tensor imaging (DTI) and voxel‐based statistics (VBS).

Seizures during intracarotid methohexital and amobarbital testing

BACKGROUND Methohexital and amobarbital have been used as agents for Wada testing in the presurgical evaluation of patients with epilepsy. Previous experience with methohexital as an anesthetic indicates that methohexital may decrease seizure threshold and may trigger seizures. METHODS A retrospective chart review of 760 intracarotid amobarbital and methohexital tests was performed to determine the frequency of seizures associated with preoperative intracarotid barbiturate testing for language and memory lateralization. RESULTS Sixteen patients (2.1%) who had seizures were found. In 3 patients, seizures occurred prior to barbiturate injection, and in 13, following barbiturate injection. After injection of amobarbital, 4 of 538 patients (0.7%) had a seizure. Nine of 222 patients had a seizure after methohexital injection (4.1%) (P=0.001). CONCLUSION Patients with a previous history of epilepsy may be at higher risk for seizures after methohexital injection as compared with amobarbital injection.