Judith Dobesberger

Video‐EEG monitoring: Safety and adverse events in 507 consecutive patients

Purpose:u2002 Video–electroencephalography (EEG) monitoring plays a central role in the presurgical evaluation of medically refractory epilepsies and the diagnosis of nonepileptic attack disorders (NEADs). The aim of this study was to analyze safety and adverse events (AEs) during video‐EEG monitoring.

Outcome of adult patients with temporal lobe tumours and medically refractory focal epilepsy

SummaryBackground. Tumours are a well-recognized cause of medically intractable epilepsies. Tumours represent the primary pathology in 10%–30% of patients undergoing surgical treatment for chronic epilepsy. This study examines the surgical and epileptological outcome of adults with temporal lobe tumoural epilepsy treated within a comprehensive epilepsy surgery programme.n Methods. Between 1999 and 2004, 99 consecutive patients have been operated for intractable temporal lobe epilepsy (TLE). Among these, 14 adult patients exhibited temporal lobe neoplasms associated with TLE. Every patient underwent a comprehensive presurgical evaluation including video-EEG monitoring, MRI, interictal PET scan, ictal SPECT and neuropsychological testing. Surgical strategies were determined in an interdisciplinary seizure conference and tailored to the findings of the presurgical evaluation. All patients were available for follow up at regular intervals after 3, 6, 12 months and yearly thereafter. Epileptological outcome was classified according to Engel [10] and the ILAE (International League Against Epilepsy)/systems [33].n Findings. The surgical procedures performed were temporal lobe resection in 3 patients, extended lesionectomy in 4 and extended lesionectomy with resection of the temporomesial structures in 7. One patient with an astrocytoma grade III underwent a second and third operation for recurrent disease. Histological results: Astrocytoma 5 patients, ganglioglioma/gangliocytoma 5, oligodendroglioma 2, ependymoma 1 and dysembryoplastic neuroepithelial tumour (DNET) 1. Postoperative follow-up was performed after 12–74 months (mean 31). The outcome according to the Engel classification indicated class IA in 9 patients, class IC in 3, and 1 each in classes IIIA and IVA. Epileptological outcome according to the ILAE classification indicated class 1 (12 patients) and class 4 (2 patients). Surgical mortality was zero and mild permanent neurological deficits due to surgery were seen in 2 patients. Postoperatively 3 patients showed a homonymous quadrantanopia.n Conclusions. Patients with drug resistant epilepsy and temporal lobe tumours should undergo evaluation in dedicated epilepsy surgery programmes.

Hippocampal formation involvement in a language-activation task in patients with mesial temporal lobe epilepsy

Summary:u2002 Purpose: The study aims to explore the contribution of the hippocampal formation to the retained language‐comprehension network in patients with unilateral mesial temporal lobe epilepsy (TLE).

Frame-based vs frameless placement of intrahippocampal depth electrodes in patients with refractory epilepsy: a comparative in vivo (application) study.

BACKGROUND:Despite progress in imaging technologies, documentation of unifocal electrical excitability is pivotal in patient selection for epilepsy surgery. OBJECTIVE:To compare the application accuracy of the Vogele-Bale-Hohner system (VBH), a maxillary fixation system with an external fiducial frame permitting frameless stereotactic guidance, with that of conventional frame-based stereotaxy for placement of intrahippocampal depth electrodes (DEs) in patients with refractory epilepsy. METHODS:Retrospective study. Comparison of two patient cohorts with DEs implanted along the occipitotemporal axis (group A, VBH; group B, frame-based stereotaxy). In vivo accuracy (lateral target localization error [TLE]), determined postoperatively by measuring the normal distance between virtual target and real electrode position at the tip and at 4cm from the tip, number of electrode contacts within the target structure, and diagnostic quality of electroencephalogram recordings were compared. RESULTS:Seventeen DEs (A, 6 electrodes, 60 contacts; B, 11 electrodes, 90 contacts) were placed. electroencephalogram recordings via DEs supported further treatment decisions in all patients. TLE was 2.433 ± 0.977 mm (SD) (95% confidence interval [CI], 1.715-3.214 mm) (A) and 1.803 ± 0.392 mm (SD) (95% CI,1.511-2.195 mm) (B) (P = .185). Maximal error was 4 mm (A) and 3.2 mm (B). TLE 4 cm from the tip was 2.166 ± 2.188 mm (SD) (95% CI,0.438-3.916 mm) (A) and 1.372 ± 0.548 mm (SD) (95% CI,1.049-1.695 mm) (B) (P = .39). Maximal error 4 cm from the tip was 6.4 mm (A) and 2.14 mm (B). On average, 7 (A) and 5 (B) electrode contacts were placed in the target region. CONCLUSION:The VBH and frame-based systems offer similar in vivo accuracy for intrahippocampal DE placement. With frame-based methods, accuracy is higher but the number of contacts per side is lower. This does not translate to clinically important differences.

Integration of multimodality imaging and surgical navigation in the management of patients with refractory epilepsy. A pilot study using a new minimally invasive reference and head-fixation system

SummaryObjectiveTo review the experience with a new system (VBH system) for minimally invasive frameless stereotactic guidance, acting as a common platform to provide multimodal image integration and surgical navigation in a consecutive series of 25 patients who underwent surgery for drug-resistant seizures.MethodsThe usefulness of the VBH system for integrating all images to produce one dataset and for intraoperative instrument guidance and navigation was judged semiquantitatively in a three-tiered scale (+, ++, +++). Seizure outcome was classified according to Engel.ResultsThe presurgical evaluation extended over 21.2xa0months (mean). A total of 141 registrations of images were performed (mean 5.6 per patient, range: 2 to 16). In 19 (76%) of 25 patients structural data fused with functional data were used for the presurgical workup. Six patients proceeded directly to navigated resection. Nineteen patients (76%) underwent invasive recording, of whom 13 underwent resective surgery. In seven patients (28%) the combination of multimodal image fusion and intra-operative stereotactic guidance was judged “essential” (+++) to remove the epileptogenic zone. Integration of all images to form one dataset was “essential” (+++) for decision making in 15 and “helpful” (++) in 4 patients (overall 76% of patients). Intraoperative use of frameless neuronavigation was “essential” (+++) in ten and “helpful” (++) in all remaining patients. Eighty percent of the patients achieved satisfactory seizure outcome after 1 year.ConclusionThe VBH system is a safe and effective non-invasive tool for repetitive imaging, multimodal image fusion and frameless stereotactic surgical navigation in candidates for epilepsy surgery.

Idiopathic generalised epilepsy of late onset: a separate nosological entity?

Aim Seizure onset in idiopathic generalised epilepsies (IGE) is considered to be rare after the second decade of life. The authors aimed to explore age of seizure onset in patients with IGE and compare ‘classical’ onset to late onset cases. Methods Patients with IGE, treated at the outpatient epilepsy clinic (Medical University of Innsbruck, Austria, 1985–2006, n=798) were retrospectively screened. The inclusion criteria were: diagnosis of IGE, more than two follow-up (FU) visits, duration of FU more than 1u2005year and normal brain imaging. The authors analysed demographic data, age of seizure onset, seizure types, syndromes, neuroimaging and EEG findings, seizure triggers and seizure freedom for 1 and 5u2005years at last FU. Results A total of 492 patients (mean age at seizure onset 14.6u2005years, range 0.1–55, SD 7.9) with IGE were identified: childhood absence epilepsy (n=113, range 1–55, SD 6.5), juvenile absence epilepsy (n=75, range 4–39, SD 5.1), juvenile myoclonic epilepsy (n=112, range 2–39, SD 5.7), and epilepsy with grand mal seizures on awakening (n=192 range 1–52, SD 17.3). Population was stratified into three groups: 28 patients with seizure onset at >30u2005years, 180 patients between 15 and 30u2005years and 284 patients <15u2005years. The distribution of seizure types and epilepsy syndromes differed significantly in a group comparison (p<0.001); seizure outcome and other clinical variables did not differ throughout the groups. Conclusion Apart from age-related onset of seizure types and syndromes with a loose upper limit of onset age, patients with a late onset did not differ from their younger counterparts. These data do not support the view of IGE of late onset as a separate syndrome.

Frameless Stereotactic Placement of Foramen Ovale Electrodes in Patients with Drug-refractory Temporal Lobe Epilepsy

OBJECTIVE Semi-invasive foramen ovale electrodes (FOEs) are used as an alternative to invasive recording techniques in the presurgical evaluation of patients with temporal lobe epilepsy. To maximize patient safety and interventional success, frameless stereotactic FOE placement by use of a variation of an upper jaw fixation device with an external fiducial frame, in combination with an aiming device and standard navigation software, was evaluated by the Innsbruck Epilepsy Surgery Program. METHODS Patients were immobilized noninvasively with the Vogele-Bale-Hohner headholder (Medical Intelligence GmbH, Schwabmünchen, Germany) to plan computed tomography and surgery. Frameless stereotactic cannulation of the foramen and intracranial electrode placement were achieved with the help of an aiming device mounted to the base plate of the headholder. Ease of applicability, safety, and results obtained with foramen ovale recording were investigated. RESULTS Twenty-six FOEs were placed in 13 patients under general anesthesia. The foramen ovale was successfully cannulated in all patients. One patient reported transient painful mastication after the procedure as a complication attributable to use of the Vogele-Bale-Hohner mouthpiece. In one patient, a persistent slight buccal hypesthesia was present 3 months after the procedure. To pass the foramen, slight adjustments in the needle position had to be made in 10 sides (38.4%). To place the intracranial electrodes, adjustments were necessary six times (23.7%). An entirely new path had to be planned once (3.8%). Seizure recording provided conclusive information in all patients (100%). Outcome in operated patients was Engel Class Ia in six patients, Class IId in one patient, Class IIb in one patient, and Class IVa in one patient (minimum follow-up, 6 mo). CONCLUSION The Vogele-Bale-Hohner headholder combined with an external registration frame eliminates the need for invasive head clamp fixation. FOE placement can be planned “offline” and performed under general anesthesia later. This can be valuable in patients with distorted anatomy and/or small foramina or in patients not able to undergo the procedure under sedation. Results are satisfactory with regard to patient safety, patient comfort, predictability, and reproducibility. FOEs supported further treatment decisions in all patients.

Tuberous sclerosis complex with unilateral perisylvian polymicrogyria and contralateral hippocampal sclerosis—A case report

Malformations of cortical development (MCD) encompass a wide spectrum of brain disorders. Although rare, the combination of certain MCD may occur. We report a rare case of combination of three distinct cerebral pathologies: tuberous sclerosis, polymicrogyria and hippocampal sclerosis in a patient with intractable epilepsy. Ictal EEG and ictal SPECT suggested right perisylvian area as a seizure onset zone. However, on MRI multiple potentially epileptogenic lesions were identified. The neurobiological background of the coexistence of different types of malformations of cortical development remains enigmatic.

Selective serotonin reuptake inhibitors prolong seizures – Preliminary results from an observational study

OBJECTIVEnSelective serotonin reuptake inhibitors (SSRIs) are often used in the treatment of depressive disorders in patients with epilepsy. Pro- and anti-convulsive effects of SSRIs are discussed controversially. The aim of this study was to investigate a possible impact of SSRIs-treatment on duration of EEG and clinical features in epilepsy patients.nnnMETHODSnWe studied video-EEG data from 162 patients with focal epilepsies between January 2006 and March 2008 using a case-control study design. Eleven patients with 19 complex focal seizures (CFSs) and 16 secondary generalized tonic-clonic seizures (sGTCSs) treated with SSRIs (SSRIs+) were matched to 13 patients without SSRIs-treatment (SSRIs-). We compared duration of ictal EEG in CFSs and sGTCSs, duration of convulsions in sGTCSs and duration of postictal EEG suppression after sGTCSs in SSRIs+ and SSRIs- patients.nnnRESULTSnIctal EEG duration of both, CFSs and sGTCSs, was significantly longer in SSRIs+ patients than in SSRIs- patients (p=0.004 and p=0.015, respectively). No significant difference was found between convulsive phase duration of sGTCSs as well as duration of postictal EEG suppression after sGTCSs in both groups.nnnCONCLUSIONnSeizures last significantly longer in patients with epilepsy and SSRIs as co-medication. A causative role of SSRIs in ictal activity has to be explored in prospective studies.