The connectivity-based architecture of the human piriform cortex.

The anatomy of the human piriform cortex (PC) is poorly understood. We used a bimodal connectivity-based-parcellation approach to investigate subregions of the PC and its connectional differentiation from the amygdala. One hundred (55 % female) genetically unrelated subjects from the Human Connectome Project were included. A region of interest (ROI) was delineated bilaterally covering PC and amygdala, and functional and structural connectivity of this ROI with the whole gray matter was computed. Spectral clustering was performed to obtain bilateral parcellations at granularities of k = 2-10 clusters and combined bimodal parcellations were computed. Validity of parcellations was assessed via their mean individual-to-group similarity per adjusted rand index (ARI). Individual-to-group similarity was higher than chance in both modalities and in all clustering solutions. The amygdala was clearly distinguished from PC in structural parcellations, and olfactory amygdala was connectionally more similar to amygdala than to PC. At higher granularities, an anterior and ventrotemporal and a posterior frontal cluster emerged within PC, as well as an additional temporal cluster at their boundary. Functional parcellations also showed a frontal piriform cluster, and similar temporal clusters were observed with less consistency. Results from bimodal parcellations were similar to the structural parcellations. Consistent results were obtained in a validation cohort. Distinction of the human PC from the amygdala, including its olfactory subregions, is possible based on its structural connectivity alone. The canonical fronto-temporal boundary within PC was reproduced in both modalities and with consistency. All obtained parcellations are freely available.

Stiripentol in the treatment of adults with focal epilepsy- a retrospective analysis.

OBJECTIVES: The aim of the present study was to evaluate the safety and efficacy of the add-on treatment of stiripentol (STP) in adult patients with severely pharmacoresistant focal or multifocal epilepsy. METHODS: Data on adult patients treated with STP from March 2007 to July 2020 and with at least one clinical follow-up (FU) were retrospectively reviewed. Data on tolerability, efficacy and concomitant medication were evaluated at baseline, 6 months (5.5 ± 1.6 months (mean ± SD)) and 12 months (13.1 ± 3.9 months (mean ± SD)). RESULTS: Data of 22 patients (54.5% male, mean age 34.4 ± 17.79 years (mean ± SD), including mean duration of epilepsy 17.6 ± 25.5 years (mean ± SD), median seizure frequency 30 ± 20 (median ± MAD) per month, and 63.6% being severely intellectually disabled, with 3 to 18 previous anti-seizure-drugs (ASD), were collected. After 6 months, 72.7% of the patients were still taking STP, and 31% of the patients were responders, including 13% who were seizure-free. The 12-month retention rate was 54.4 %, the response rate was 36.4% and 13.6% of patients were seizure-free at the 12-month FU. Reasons for discontinuation were increased seizure frequency, hyperammonaemia and encephalopathy. CONCLUSION: STP seems to be a useful option in the treatment of patients with severely pharmacoresistant epilepsy. Prospective trials are necessary to examine the efficacy of STP in adult patients with pharmacoresistant focal epilepsy.

[Epilepsy and Pregnancy]. / Epilepsie und Schwangerschaft.

BACKGROUND: On average, female patients with epilepsy have 0.9 children, which is below the birth rate of healthy women. One reason is insufficient counselling. OBJECTIVES: To summarize the current data relevant to counselling pregnant women with epilepsy. MATERIALS AND METHODS: Discussion of research and recommendations concerning seizure control during pregnancy, pregnancy and birth complications, congenital malformations, and breastfeeding. RESULTS: Changes in seizure frequency during pregnancy are variable and partly due to changes in the serum concentrations of antiepileptic drugs. Epilepsy patients have a slightly higher risk for some pregnancy and birth complications including spontaneous abortion, pre- and postpartum bleeding, induction of labour, and caesarean section. In particular, the administration of valproic acid can lead to congenital malformations and a lower IQ of the child. Folic acid seems to have a protective effect. Data concerning breastfeeding are insufficient. CONCLUSIONS: If possible, epilepsy patients should be treated with a low-dose monotherapy during pregnancy and valproic acid should be avoided. Treatment with lamotrigine requires frequent control of serum concentration. Supplementary folic acid (5 mg daily dose) is recommended. Epilepsy is not an indication for a caesarean section.

[Brivaracetam for add-on treatment in focal epilepsy]. / Brivaracetam zur Zusatztherapie bei fokalen Epilepsien.

Brivaracetam is the latest antiepileptic drug to be approved for adjunctive therapy in focal epilepsy and has a high affinity as a SV2A ligand. The aim of this review article is to summarize the data from the pivotal studies in which more than 2000 patients received brivaracetam. A significant median reduction in seizures from 30.5 % to 53.1 % for 50 mg/day, from 32.5 % to 37.2 % for 100 mg/day and 35.6 % for 200 mg/day could be demonstrated. Overall brivaracetam appears to be well-tolerated, with fatigue, dizziness and somnolence being the main adverse side effects. An immediate change from levetiracetam to brivaracetam at a conversion ratio of 10:1 to 15:1 seems feasible and could alleviate behavioral side effects related to treatment with levetiracetam. A swift permeability into brain tissue and a faster onset of action compared to levetiracetam suggest that brivaracetam could be useful in emergency situations.

Brain energy metabolism in early MSA-P: A phosphorus and proton magnetic resonance spectroscopy study.

INTRODUCTION: Recently, mutations in the COQ2 gene, encoding for an enzyme involved in coenzyme Q10 biosynthesis, have been suggested to confer susceptibility risk for multiple system atrophy (MSA). Thus, the possible role of mitochondrial dysfunction in the pathophysiology of MSA has emerged. Here, we studied brain energy metabolism in vivo in early MSA-parkinsonism (MSA-P) patients and compared to healthy controls. METHODS: We have used combined phosphorus and proton magnetic resonance spectroscopy to measure high- and low-energy phosphates in the basal ganglia of early (Hoehn and Yahr stage I-III), probable MSA-P patients (N = 9) compared to healthy controls (N = 9). RESULTS: No significant changes in the high energy phosphates and other parameters reflecting the energy status of the cells were found in the basal ganglia of MSA-P patients compared to healthy controls. N-acetylaspartate was significantly reduced in MSA-P compared to healthy controls and correlated with the Unified Multiple System Atrophy Rating Scale. CONCLUSION: Brain energy metabolism in early MSA-P is not impaired, despite the presence of impaired neuronal integrity. This may imply that mitochondrial dysfunction may not play a primary role in the pathophysiology of MSA, at least in European populations.

Stiripentol for the treatment of super-refractory status epilepticus.

BACKGROUND: To determine whether stiripentol (STP) might be a treatment option in super-refractory status epilepticus (SRSE). METHODS: Medical records of patients treated due to a status epilepticus in Marburg between January 2013 and June 2014 were reviewed for administration of STP. Primary outcome measures were resolution of SE after initiation of STP. RESULTS: Five adult patients were started with STP due to SRSE. The median age was 78 years (interquartile range [IQR] 11 years), and four patients were female. The median duration of SRSE before initiation of STP was 39 days (IQR 16 days), and the median number of anticonvulsants used before was 6 (IQR 1). SRSE ceased in three patients within 2-4 days after the start of STP. In two patients, SRSE continued after administration of STP and further escalation of anticonvulsant regimen. Both were switched eventually to supportive care only. None serious side effects were observed while on STP. CONCLUSIONS: Based on our presented cases and previous experimental animal data, STP may prove useful in treating super-refractory SE. Prospective trials are warranted to examine the efficacy of the STP in adults with refractory SE and to examine whether earlier treatment leads to better control of SE.

[New aspects in the field of epilepsy]. / Neues auf dem Gebiet der Epilepsien.

Regarding epilepsy several new developments can be reported. The International League Against Epilepsy (ILAE) has suggested a new definition of epilepsy, for the first time including a definition of epilepsy resolution. Progress in the diagnosis relates to new genetic findings, improvements in magnetic resonance imaging (MRI) and the increasing use of stereo electroencephalograms (sEEG). Regarding treatment there are new clinically relevant data on the pathophysiology and prevention of sudden unexpected death in epilepsy (SUDEP). Zonisamide has been approved by the European Medicines Agency (EMA) for monotherapy in adults with focal seizures and combination therapy in children aged ≥ 6 years. Retigabin and perampanel have been approved but are currently taken off the market in Germany (only) because the Gemeinsamer Bundesausschuss (GBA, Joint Federal Committee) did not find any additional therapeutic value as compared to lamotrigine due to a lack of data. A decision regarding a new application for perampanel is pending. Regarding surgical treatment novel ablation techniques (e.g. stereotactic radiofrequency and laser ablation as well as focussed ultrasound ablation) and brain stimulation paradigms are under investigation. Experimental studies, generously supported by the European Union (EU) and the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) are focusing on (opto-)genetic (e.g. using lentoviral transfection), epigenetic (e.g. micro-RNA-related) approaches and on the investigation of neuronal micronetworks.

Definition of DLPFC and M1 according to anatomical landmarks for navigated brain stimulation: inter-rater reliability, accuracy, and influence of gender and age.

The optimization of the targeting of a defined cortical region is a challenge in the current practice of transcranial magnetic stimulation (TMS). The dorsolateral prefrontal cortex (DLPFC) and the primary motor cortex (M1) are among the most usual TMS targets, particularly in its "therapeutic" application. This study describes a practical algorithm to determine the anatomical location of the DLPFC and M1 using a three-dimensional (3D) brain reconstruction provided by a TMS-dedicated navigation system from individual magnetic resonance imaging (MRI) data. The coordinates of the right and left DLPFC and M1 were determined in 50 normal brains (100 hemispheres) by five different investigators using a standardized procedure. Inter-rater reliability was good, with 95% limits of agreement ranging between 7 and 16 mm for the different coordinates. As expressed in the Talairach space and compared with anatomical or imaging data from the literature, the coordinates of the DLPFC defined by our algorithm corresponded to the junction between BA9 and BA46, while M1 coordinates corresponded to the posterior border of hand representation. Finally, we found an influence of gender and possibly of age on some coordinates on both rostrocaudal and dorsoventral axes. Our algorithm only requires a short training and can be used to provide a reliable targeting of DLPFC and M1 between various TMS investigators. This method, based on an image-guided navigation system using individual MRI data, should be helpful to a variety of TMS studies, especially to standardize the procedure of stimulation in multicenter "therapeutic" studies.

[Non-convulsive status epilepticus: temporary fad or reality in need of treatment?]. / Nonkonvulsiver Status epilepticus : Modeerscheinung oder behandlungspflichtige Realität?

The term non-convulsive status epilepticus (NCSE) refers to a heterogeneous group of diseases with different etiology, prognosis and treatment. The different forms of NCSE comprise about 25-50% of all status epilepticus cases. The most frequent form encountered in clinical practice is complex-partial SE but the rarer conditions of absence status, aura status and subtle SE are also included under this category. A diagnosis of NCSE should be considered in all patients with otherwise unexplained changes in consciousness or behavior and this diagnosis demands rapid further diagnostic work up including clinical examination, a detailed clinical history from the patient or an accompanying person, cranial computed tomography (CCT) and an electroencephalogram (EEG). If signs of an infectious or inflammatory disorder are present, a spinal tap is indicated. The EEG is of high relevance although interpretation can be challenging in NCSE.Absence status is usually treated by benzodiazepines and if necessary a broad spectrum anticonvulsive drug (ACD) such as valproic acid (VPA) can be added. The treatment of complex-partial SE follows the same scheme as that of generalized tonic-clonic SE and an initial benzodiazepine (i.v. lorazepam or intramuscular midazolam) followed by a bolus of one of the ACDs available as i.v. solution (e.g. VPA, phenytoin, phenobarbitol or levetiracetam). The third treatment step is general anesthesia if NCSE fails to be controlled. The aggressiveness of the applied therapy depends on the severity of the NCSE and the general condition of the patient. The prognosis is determined by the subtype of NCSE and the underlying etiology.

DTI reveals hypothalamic and brainstem white matter lesions in patients with idiopathic narcolepsy.

BACKGROUND: Symptomatic narcolepsy is often related to hypothalamic, pontine, or mesencephalic lesions. Despite evidence of disturbances of the hypothalamic hypocretin system in patients with idiopathic narcolepsy, neuroimaging in patients with idiopathic narcolepsy revealed conflicting results and there is limited data on possible structural brain changes that might be associated with this disorder. METHODS: We investigated with diffusion tensor imaging (DTI) whether microstructural abnormalities in the brain of eight patients with idiopathic narcolepsy with cataplexy are detectable compared to 12 healthy controls using a 1.5T MRI scanner. Whole-head DTI scans were analyzed without an a priori hypothesis. Voxelwise statistical analysis of fractional anisotropy (FA) data was performed using Tract-Based Spatial Statistics (TBSS), a non-linear analysis approach. RESULTS: Patients with narcolepsy showed microstructural white matter changes in the right hypothalamus as well as in the left mesencephalon, pons, and medulla oblongata. Additionally, areas in the left temporal lobe, the pre- and postcentral gyrus, the frontal and parietal white matter, the corona radiata, the right internal capsule, and the caudate nucleus had altered microstructure in patients with narcolepsy. CONCLUSIONS: Our study shows widespread microstructural white matter changes that are not visible on conventional MRI scans in patients with idiopathic narcolepsy. In support of the evidence from patients with symptomatic narcolepsy, we found microstructural changes in the hypothalamus, mesencephalon, pons, and medulla oblongata. Changes are in accordance with disturbances of the hypothalamic hypocretin system and its projections to mesencephalic and pontine areas regulating REM sleep.

Intraoperative ultrasound in malformations of cortical development.

PURPOSE: Malformations of cortical development (MCD) are a common cause of medically refractory focal epilepsy. However, the intraoperative definition of MCD can be challenging. In this study we assess the feasibility of intraoperative ultrasound (IOUS) for the intraoperative localization of MCD. MATERIALS AND METHODS: Five epilepsy patients with at least one suspected lesion of MCD were operated with the aid of IOUS. IOUS was compared to preoperative MRI and histopathology. RESULTS: In three cases of focal cortical dysplasia (FCD) type IIB and one case of periventricular heterotopia, the lesions could be delineated well on IOUS and the configuration of the lesion corresponded to the appearance on MRI. However, only one of two FCD type I lesions could be detected on IOUS. CONCLUSION: IOUS can be helpful in defining FCD IIB as well as periventricular heterotopia intraoperatively, but this seems to be more difficult in FCD type I.

Men and women are different: diffusion tensor imaging reveals sexual dimorphism in the microstructure of the thalamus, corpus callosum and cingulum.

INTRODUCTION: Numerous magnetic resonance imaging (MRI) studies have addressed the question of morphological differences of the brain of men and women, reporting conflicting results regarding brain size and the ratio of gray and white matter. In the present study, we used diffusion tensor imaging (DTI) to delineate sex differences of brain white matter. METHODS: We investigated brain microstructure in 25 male and 25 female healthy subjects using a 3T MRI scanner. Whole-head DTI scans were analyzed without a-priori hypothesis using Tract-Based Spatial Statistics (TBSS) calculating maps of fractional anisotropy (FA), radial diffusivity (RD, a potential marker of glial alteration and changes in myelination) and axial diffusivity (AD, a potential marker of axonal changes). RESULTS: DTI revealed regional microstructural differences between the brains of male and female subjects. Those were prominent in the thalamus, corpus callosum and cingulum. Men showed significantly (p<0.0001) higher values of fractional anisotropy and lower radial diffusivity in these areas, suggesting that the observed differences are mainly due to differences in myelination. DISCUSSION: As a novel finding we showed widespread differences in thalamic microstructure that have not been described previously. Additionally, the present study confirmed earlier DTI studies focusing on sexual dimorphism in the corpus callosum and cingulum. All changes appear to be based on differences in myelination. The sex differences in thalamic microstructure call for further studies on the underlying cause and the behavioral correlates of this sexual dimorphism. Future DTI group studies may carefully control for gender to avoid confounding.

Magnetic resonance imaging in progressive supranuclear palsy.

Progressive supranuclear palsy (PSP) is a tauopathy, presenting clinically most often with a symmetrical akinetic-rigid syndrome, postural instability, supranuclear gaze palsy and frontal dementia. In the absence of reliably validated biomarkers, the diagnosis of PSP in vivo is presently based on clinical criteria, which to date do not include supporting imaging findings, as is accepted for other neurodegenerative diseases. However, data from conventional magnetic resonance imaging (MRI) and various advanced MRI techniques including magnetic resonance volumetry, voxel-based morphometry, diffusion-weighted and diffusion-tensor imaging, magnetization transfer imaging and proton resonance spectroscopy suggest that MRI can contribute valuable information for the differential diagnosis of PSP. We review here the presently published literature concerning MRI in PSP and discuss the potential role of MRI in differentiating PSP from other parkinsonian syndromes.

[Primary brain tumors and brain metastases. Symptomatic epilepsy and driving ability - systematic review and expert opinion]. / Primäre Hirntumoren und Hirnmetastasen. Symptomatische Epilepsie und Fahreignung - Expertenumfrage und systematisches Review.

PURPOSE: Primary brain tumors and metastases are common causes of symptomatic epilepsy. Seizures, neurological and neuropsychological deficits can interfere with driving ability. The present paper aims to systematically review the incidence of epileptic seizures in brain tumor patients and to discuss driving ability in the context of the current German guidelines and expert opinions. METHODS: To evaluate the incidence of epileptic seizures which occur at the beginning and in the course of the disease, we performed a systematic literature research in PubMed from 1960 to 2007. Additionally on the basis of this data we performed a survey collecting expert opinions regarding the driving ability of brain tumor patients from members of the German working groups "Arbeitsgemeinschaft für prächirurgische Epilepsiediagnostik und operative Epilepsietherapie" (Working Group for Presurgical Epilepsy Diagnostics and Operative Epileptic Therapy) and "Neuroonkologische Arbeitsgemeinschaft" (Neuro-oncological Working Group). RESULTS: The incidence of epileptic seizures depends on the entity, dignity and localization of the tumor. The driving ability of brain tumor patients is not explicitly regulated in Germany. Of the interviewed experts 72% judged the guidelines to be precise enough and 44% did not want to deprive the patients of their driving ability without a first seizure, independent of the individual risk. DISCUSSION: The available studies are methodologically insufficient and show that a further evaluation is necessary to assess the driving ability. Possible restrictions of the driving ability in patients with a high risk of seizures in the course of the disease have to take into account the balance between individual rights and the interests of the general public.

Evaluation of MRI criteria (1.5 T) for the diagnosis of hippocampal sclerosis in healthy subjects.

PURPOSE: The presence of hippocampal sclerosis (HS) on MRI has a great impact on the clinical evaluation and counselling of patients with temporal lobe epilepsy (TLE) and is considered as a key criterion for the decision to recommend epilepsy surgery. However, neuropathological studies describe evidence of HS in up to 10% of non-epileptic individuals, questioning the impact of this MRI finding in patients with TLE. We evaluated the prevalence of HS on MRI in the general population. METHODS: 100 healthy subjects and 10 patients with TLE due to HS were investigated in a prospective study using a specific protocol for the detection of hippocampal pathology (coronal FLAIR, coronal T2 TSE and a T1 weighted 3D SPGR sequence). RESULTS: HS was detected in none of the healthy subjects (95% confidence interval=0-3.6%), but in all patients. Inter-rater agreement was perfect for presence of HS. Thirty-three subjects had an unilaterally enlarged temporal horn as an isolated secondary criterion for HS and inter-rater agreement was slight for this point. Incidental pathological findings were detected in two patients (2%): one had a low grade astrocytoma (1%), one an aneurysm of the posterior communicating artery (1%). CONCLUSIONS: HS was not diagnosed in healthy subjects, supporting its impact on the evaluation of patients with temporal lobe epilepsy. An unilateral enlarged temporal horn that occurred in one third of the healthy subjects should not be considered as a pathologic finding or even as a marker for HS.

Functional transcranial Doppler sonography and a spatial orientation paradigm identify the non-dominant hemisphere.

RATIONALE: Functional transcranial Doppler sonography (fTCD) during word generation is well established for language lateralization. In this study, we evaluated a fTCD paradigm to reliably identify the non-dominant hemisphere. METHODS: Twenty-nine right-handed healthy subjects (27.1+/-7.6 years) performed the 'cube perspective test' [Stumpf, H., & Fay, E. (1983). Schlauchfiguren: Ein Test zur Beurteilung des räumlichen Vorstellungsvermögens. Verlag für Psychologie Dr. C. J. Hogrefe, Göttingen, Toronto, Zürich] a spatial orientation task, while the cerebral blood flow velocity (CBFV) was simultaneously measured in both middle cerebral arteries (MCAs). In addition, the established word generation paradigm for language lateralization was performed. Subjects with atypical language representation were excluded. Data were analysed offline with the software Average, which performed a heart-cycle integration and a baseline-correction and calculated a lateralization index (LI) with its standard error of the mean increase in CBFV separately for both MCAs. RESULTS: Twenty-one of 29 subjects (72.4%) lateralized to the right hemisphere (chi2=5.828, p=0.016). The mean LI of the spatial orientation paradigm pointed to the right hemisphere (x =-1.9+/-3.2) and was different from the LI of word generation (x =3.9+/-2.2;p<0.001). There was no correlation between the LI of spatial orientation and word generation (R=0.095, p=0.624). Age of the subjects did not correlate with the LI during spatial orientation (p>0.05) but negatively with the LI during word generation (R=-0.468, p=0.010). The maximum increase of CBFV was greater in the spatial orientation (14.0%+/-3.6%) than in the word generation paradigm (9.4%+/-4.0%; p<0.001). CONCLUSIONS: In more than two thirds of the subjects with left-sided language dominance, the spatial orientation paradigm was able to identify the non-dominant hemisphere. The results suggest both paradigms to be independent of each other. The spatial orientation paradigm, therefore, appears to be a non-verbal fTCD paradigm with possible clinical relevance.

The Wada test in Austrian, Dutch, German, and Swiss epilepsy centers from 2000 to 2005: a review of 1421 procedures.

Twenty-six Austrian, Dutch, German, and Swiss epilepsy centers were asked to report on use of the Wada test (intracarotid amobarbital procedure, IAP) from 2000 to 2005 and to give their opinion regarding its role in the presurgical diagnosis of epilepsy. Sixteen of the 23 centers providing information had performed 1421 Wada tests, predominantly the classic bilateral procedure (73%). A slight nonsignificant decrease over time in Wada test frequency, despite slightly increasing numbers of resective procedures, could be observed. Complication rates were relatively low (1.09%; 0.36% with permanent deficit). Test protocols were similar even though no universal standard protocol exists. Clinicians rated the Wada test as having good reliability and validity for language determination, whereas they questioned its reliability and validity for memory lateralization. Several noninvasive functional imaging techniques are already in use. However, clinicians currently do not want to rely solely on noninvasive functional imaging in all patients.

Intravenous levetiracetam in the treatment of benzodiazepine refractory status epilepticus.

In 2006, levetiracetam was approved as the first of the newer anticonvulsive drugs as an intravenous formulation (ivLEV) for patients with epileptic seizures who are unable to take oral medication. We report our experience with the use of ivLEV for the treatment of 18 episodes of benzodiazepine refractory focal status epilepticus (SE) in 16 patients, including four patients with secondary generalised SE. SE was controlled in all patients by the given combination of drugs; application of further antiepileptic medications after ivLEV was necessary in two episodes. No severe side effects occurred. Our data suggest that ivLEV may be an alternative for the treatment of SE in the future, even in patients that did not respond to benzodiazepines. A large prospective, randomised, controlled study is warranted to investigate the efficacy and safety of ivLEV for the treatment of SE.