Gerald Walser

Paracelsus Medical University Salzburg, Salzburg, Salzburg, Austria

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Publications (43)122.94 Total impact


  • No preview · Poster · Sep 2015
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    ABSTRACT: Introduction: Identifying seizures with prolonged duration during video-electroencephalographic (EEG) monitoring is of importance to inform clinicians when to start emergency treatment of seizures to prevent status epilepticus. The aims of this study were to assess the clinical and EEG seizure duration (SD) in consecutive patients with epilepsy who underwent prolonged video-EEG monitoring and to identify a seizure type-dependent time point to start emergency treatment based on the likelihood that seizures will not stop spontaneously. Furthermore, we sought to determine predictors of SD and explored the relationship between antiepileptic drug (AED) serum levels and SD. Material and methods: We retrospectively analyzed 1796 seizures in 200 patients undergoing video-EEG monitoring between January 2006 and March 2008. Results: Focal simple seizures lasted significantly shorter (clinical SD: 28s, EEG SD: 42s) compared with focal complex seizures (clinical SD: 64s, EEG SD: 62s), and both seizure types lasted significantly shorter compared with secondarily generalized tonic-clonic seizures (GTCSs; clinical SD: 90s, EEG SD: 96s). There was no difference between the duration of the convulsive phase of primary GTCSs (defined as nonfocal) and that of secondarily GTCSs (each 65s). Cumulative clinical SD (99%) was 7min in focal complex seizures and 11min in focal simple seizures. Mixed linear regression model demonstrated that history of status epilepticus (P=0.034), temporal lobe seizure onset (P=0.040), and MRI lesions (P=0.013) were significantly associated with logarithmic EEG SD in focal epilepsies recorded with scalp electrodes. We found significant negative correlations between the AED serum level and the EEG SD in patients treated with monotherapy: carbamazepine (P<0.001), levetiracetam (P=0.001), oxcarbazepine (P=0.001), and valproic acid (P=0.038) but not with lamotrigine monotherapy and EEG SD. Discussion: Based on the results of this study, we propose 2min of convulsive seizure activity (irrespective of focal or generalized onset) as a prolonged seizure, which could serve as a time point to consider treatment to prevent status epilepticus. In focal complex seizures, we suggest an upper limit of 7min, and in focal simple seizures 11min, as definition of prolonged seizures. History of status epilepticus, temporal seizure onset, and lesional MRI findings are factors associated with significantly longer SD. Negative correlations of carbamazepine, levetiracetam, oxcarbazepine, and valproic acid serum levels and SD suggest a prolonging effect on seizures during withdrawal of these AEDs during video-EEG monitoring sessions. This article is part of a Special Issue entitled "Status Epilepticus".
    Full-text · Article · Apr 2015 · Epilepsy & Behavior
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    ABSTRACT: Early identification of potential epilepsy surgery candidates is essential to the treatment process. To evaluate the clinical applicability of the ILAE definition of drug resistant epilepsy and its potential in identifying surgical candidates earlier compared to three established “older” definitions of drug resistant epilepsy. Retrospective analysis of 174 patients who underwent epilepsy surgery between 1998 and 2009. Clinical factors and course of disease were extracted from patients' charts. Drug resistant epilepsy was classified according to four definitions and the time until fulfillment of criteria compared. Mean time to fulfillment of criteria of drug resistant epilepsy ranged from 11.8 (standard deviation (SD) 9.8) to 15.6 years (SD 11.3). Time to drug resistance was significantly longer applying the only definition, requiring failure of three antiepileptic drugs (AEDs) (Canada definition), whereas time to fulfillment of all other definitions did not differ. Fifty percent of all patients experienced a seizure free period of ≥1 year prior to being classified as drug resistant, 13% entered another 1-year remission after fulfilling any criteria for drug resistance. We conclude that the ILAE definition identifies drug resistant epilepsy, with similar latency like two of three formerly used definitions. It is an easy applicable tool to minimize the delay of referral to a specialized center. Intermittent remissions delay assessment of drug resistance for all definitions and 13% of patients enter a remission despite established drug resistance.
    Full-text · Article · Jan 2015
  • G. Bauer · G. Walser · I. Unterberger
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    ABSTRACT: Jeder Anfall verändert das Bewusstsein, sei es quantitativ (Wachheit) oder qualitativ (Inhalte). Absencen und fokale komplexe Anfälle sowie deren Statusformen sind durch Bewusstseinsstörungen mit Reaktions- und Erinnerungslosigkeit gekennzeichnet. Aufgrund von Befunden simultaner Untersuchungen durch Elektroenzephalographie (EEG) und funktioneller Magnetresonanztomographie wurde eine kausale Funktionsstörung der Wecksysteme angenommen. Klinische und EEG-Untersuchungen hingegen favorisieren eine rein kortikale Ausbreitung der inhibitorischen Komponente des Anfallsgeschehens. Ausgedehnte kortikale Defizitsymptome im „unresponsive wakefullness syndrome“ oder im minimal-bewussten Zustand gehen einher mit einer kompensatorischen Überaktivität der Wecksysteme. Die Befunde bei Anfällen könnten analog erklärt werden. Die Propagation des Anfalls mündet in einer diffusen kortikalen Inhibition (Bewusstseinsstörung) und tiefe Strukturen reagieren sekundär mit einem Weckversuch. Im Grand mal hingegen sind die Patienten komatös, eine direkte Rolle der Wecksysteme scheint wahrscheinlich. Bewusstseinsstörungen dienen als Kriterium für die Klassifikation von Anfällen. Die Überbetonung dieses Kriteriums geht mit einem Informationsverlust einher. Ein einfaches Sammeln von verifizierbaren Symptomen kann davor schützen. Abstract Every epileptic seizure changes consciousness in terms of wakefulness or the contents of consciousness. Absence and focal complex seizures are characterized by a loss of both reaction and memory. The results of simultaneous electroencephalography (EEG)/functional magnetic resonance imaging studies suggest a pivotal role of the arousal systems. Clinical and EEG observations, however, stress a purely cortical propagation of the inhibitory components of seizure activities. Unresponsive wakefulness syndrome or minimally conscious state is characterized by severe cortical deficits accompanied by a compensatory over-activation of the arousal systems. The sequence of events in seizures might be explained in a similar way. Diffuse cortical inhibition results in loss of reaction and memory and leads to secondary activation of the arousal systems. In generalized tonic-clonic seizures, patients are truly comatose, probably due to a causal involvement of the deep structures. Seizures are classified according to disturbances of consciousness; however, classifications based solely on this criterion neglect important details. Therefore, a simple collection of verifiable symptoms can avoid loss of information.
    No preview · Article · Jan 2015 · Zeitschrift für Epileptologie
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    ABSTRACT: Introduction Juvenile myoclonic epilepsy (JME) is a genetic generalised epilepsy syndrome. Under appropriate antiepileptic drugs (AED) up to 85% of patients become seizure-free, but many may have a relapse after AED withdrawal. Methods We retrospectively studied 242 patients with JME at the Department of Neurology, Medical University Innsbruck, Austria (1975–2006). We analyzed age at seizure onset, age at last follow up, seizure types, photosensitivity, seizure outcome and neuroimaging findings; inclusion criterion was a medical treatment period of > 2 years; exclusion criteria were traumatic or infectious brain injury before the onset of JME and/or gross structural pathology on neuroimaging. Results We identified 175 patients (111 women) with a median age at seizure onset of 15 years, (range 3–46) and a median age at follow-up (FU) of 38 years (range 14–87; median FU 8 years, range 2–38). Fourteen per cent showed (24/175) photosensitivity on routine EEG. Seizure Outcome: 62% (109/175) were seizure-free of myoclonic seizures (MS), generalised tonic clonic seizures (GTCS) and absence seizures (AS) for >1 year, and 53% (94/175) for >2 years, including 16 patients (9%) without AEDs. Thirty-one per cent (54/175) were seizure-free between two and five years, 15% (26/175) between six and 10, and 8% (14/175) >10 years; 38% (66/175) were not seizure-free. Not seizure-free patients had more often MS, AS and GTCS within the first year of epilepsy than those who were seizure-free at last FU (11% vs. 3%, Chi2 = 4.679, df = 1, p = 0.043). Seizure-free patients had more often MS and GTCS as last seizure types in the year before becoming seizure-free (37% vs. 15%, p = 0.003), whereas in not seizure-free group MS only and GTCS only persisted. Conclusions JME does not always need lifelong treatment, as a substantial minority of patients remain seizure free without AEDs. AS, MS and GTCS at onset of the disease are indicators of poor long-term seizure control.
    Full-text · Article · Dec 2014 · Epilepsy Research

  • No preview · Presentation · Nov 2014
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    ABSTRACT: Objective Selective 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. Methods We 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 generalised 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. Results Ictal 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. Conclusion Seizures 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.
    Full-text · Article · May 2014 · Clinical neurology and neurosurgery
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    ABSTRACT: Midbrain–hindbrain malformations (MHM) may coexist with malformations of cortical development (MCD). This study represents a first attempt to investigate the spectrum of MHM in a large series of patients with MCD and epilepsy. We aimed to explore specific associations between MCD and MHM and to compare two groups of patients: MCD with MHM (wMHM) and MCD without MHM (w/oMHM) with regard to clinical and imaging features. Two hundred and twenty patients (116 women/104 men, median age 28 years, interquartile range 20–44 years at the time of assessment) with MCD and epilepsy were identified at the Departments of Neurology and Pediatrics, Innsbruck Medical University, Austria. All underwent high-resolution MRIs (1.5-T) between 01.01.2002 and 31.12.2011. Midbrain–hindbrain structures were visually assessed by three independent raters. MHM were seen in 17% (38/220) of patients. The rate of patients wMHM and w/oMHM differed significantly (p = 0.004) in three categories of MCD (category I – to abnormal neuronal proliferation; category II – to abnormal neuronal migration; and category III – due to abnormal neuronal late migration/organization): MCD due to abnormal neuronal migration (31%) and organization (23%) were more commonly associated with MHM compared to those with MCD due to abnormal neuronal proliferation (9%). Extensive bilateral MCD were seen more often in patients wMHM compared to those w/oMHM (63% vs. 36%; p = 0.004). In wMHM group compared to w/oMHM group there were higher rates of callosal dysgenesis (26% vs. 4%; p < 0.001) and hippocampal abnormalities (52% vs. 27%; p < 0.001). Patients wMHM were younger (median 25 years vs. 30 years; p = 0.010) at the time of assessment and had seizure onset at an earlier age (median 5 years vs. 12 years; p = 0.043) compared to those w/oMHM. Patients wMHM had higher rates of learning disability (71% vs. 38%; p < 0.001), delayed developmental milestones (68% vs. 35%; p < 0.001) and neurological deficits (66% vs. 47%; p = 0.049) compared to those w/oMHM. The groups (wMHM and w/oMHM) did not differ in their response to antiepileptic treatment, seizure outcome, seizure types, EEG abnormalities and rate of status epilepticus. Presence of MHM in patients with MCD and epilepsy is associated with severe morphological and clinical phenotypes.
    Full-text · Article · Jun 2013 · Epilepsy research
  • Thomas Benke · Eva Kuen · Michael Schwarz · Gerald Walser
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    ABSTRACT: The objective of this study was to further explore proper name (PN) retrieval and conceptual knowledge in patients with left and right temporal lobe epilepsy (69 patients with LTLE and 62 patients with RTLE) using a refined assessment procedure. Based on the performance of a large group of age- and education-matched normals, a new test of famous faces and famous landmarks was designed. Recognition, naming, and semantic knowledge were assessed consecutively, allowing for a better characterization of deficient levels in the naming system. Impairment in PN retrieval was common in the cohort with TLE. Furthermore, side of seizure onset impaired stages of name retrieval differently: LTLE impaired the lexico-phonological processing, whereas RTLE mainly impaired the perceptual-semantic stage of object recognition. In addition to deficient PN retrieval, patients with TLE had reduced conceptual knowledge regarding famous persons and landmarks.
    No preview · Article · Mar 2013 · Epilepsy & Behavior
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    Full-text · Dataset · Nov 2012
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    Full-text · Dataset · Nov 2012
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    ABSTRACT: Valproic acid (VPA), as one of the most widely prescribed antiepileptic drugs (AED) for many types of epilepsy in adults and children, is associated with weight gain, alteration of adipocytokine homeostasis, insulin resistance and Non-Alcoholic Fatty Liver Disease (NAFLD). Retinol-binding protein 4 (RBP4) and Glucagon-like peptide-1 (GLP-1) are considered as important new targets in modern type 2 diabetes mellitus therapy linked to insulin resistance, NAFLD and visceral obesity acting via peripheral or central mechanisms. We herein demonstrate the lack of an influence of VPA treatment on RBP4 and GLP-1 in otherwise healthy patients. In summary, the absence of any relationship with RBP4 and GLP-1 concentrations does not suggest a role of these novel insulin resistance parameters as potential regulators of glucose and fat metabolism during VPA-therapy.
    No preview · Article · Nov 2012 · Epilepsy research
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    ABSTRACT: This study investigates the impact of generalized tonic-clonic seizures (GTCS) and antiepileptic drugs (AED) during pregnancy on gestational age (GA) and anthropometric data of newborns. One hundred twenty-nine singleton pregnancies resulting in live births from September 1999 to October 2010 in 106 women with epilepsy on AED therapy, recorded within the framework of the EURAP (International Registry of Antiepileptic Drugs and Pregnancy) program at the Department of Neurology, Medical University Innsbruck, Austria, were studied. Occurrence of ≥1 GTCS during pregnancy was associated with a shorter GA [median (range) 37.5 [35.1-41.6] vs. 39.7 [29.1-46.3] weeks; p ≤ 0.001], an overall five times higher preterm risk (p = 0.042) and a reduced birth weight in boys (2,900 [2,050-3,870] vs. 3,205 [1,575-4,355] g; p = 0.040). In primipara, when compared to multipara, GTCS ≥1 significantly reduced the GA (37.9 [35.1-41.6] vs. 39.7 [29.4-44.9] weeks; p = 0.020) and raised the incidence of low birth weight (LBW) (p = 0.022) in neonates. Antiepileptic drug polytherapy significantly increased the risk for small-for-gestational-age regarding weight (SGA(W); p = 0.035) and regarding weight and/or length (SGA(W/L); p = 0.046) when compared to monotherapy. GTCS during pregnancy was associated with diverse negative effects comprising shorter GA, an increased incidence of prematurity and LBW in primiparous women. Furthermore, AED polytherapy was correlated with an enhanced risk for SGA delivery. Re-evaluating the need for drug therapy (in particular polytherapy), maintaining seizure control for a given period before pregnancy and counseling about the importance of preventing GTCS might improve pregnancy outcome in women with epilepsy.
    Full-text · Article · Sep 2012 · Journal of Neurology
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    ABSTRACT: Selective amygdalohippocampectomy (AHE) has been associated with postoperative cerebral vasospasm (CVS) in patients with medically intractable temporal lobe epilepsy. The incidence in temporal lobe resection (TLR) is unknown. This retrospective cohort study evaluates the incidence of and risk factors for the development of CVS in patients with TLR and AHE. A total of 119 patients were included between 1998 and 2009. All patients were evaluated by standardized preoperative and postoperative transcranial Doppler sonography (TCD) evaluations and neurologic examinations. Postoperative CT scans were evaluated by an independent radiologist and the volume of bleeding within the resection cavity was quantified. Of 107 patients with longitudinal TCD data, 35 (32.7%) developed postoperative CVS. The incidence of CVS did not differ between patients with TLR and AHE. CVS was associated with female gender and a higher bleeding volume in the postoperative CT scan (p = 0.035 and 0.046). Patients with CVS showed a significantly higher incidence of postoperative neurologic signs and symptoms (48.6%) compared to patients without CVS (25%, p = 0.015). The mean length of stay was significantly prolonged in patients with diffuse CVS compared to patients with localized CVS or no CVS (28.8 ± 10.9, 24.2 ± 6.6, and 18.2 ± 6.1 days, p < 0.001). CVS is a frequent complication of surgery for temporal lobe epilepsy irrespective of the resection method. Important risk factors for the development of postoperative CVS are female gender and a higher amount of bleeding in the postoperative CT. Patients with CVS more frequently have neurologic signs and symptoms resulting in prolonged hospital stay.
    Full-text · Article · Mar 2012 · Neurology
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    ABSTRACT: Status epilepticus (SE) and seizure clusters (SC) represent neurologic emergencies with a case fatality rate up to 34%, depending on cause and comorbidity. As SE becomes more refractory to treatment over time, appropriate medication is important. This study aimed to investigate efficacy and tolerability of intravenous (IV) lacosamide (LCM) in treatment of SC and SE. Data of patients with SE or SC who were treated with IV LCM between December 2009 and February 2011 in two Austrian centers were analyzed retrospectively. Clinical information was extracted from patients' charts. Forty-eight patients (26f/22m) aged median 62 years (range 17-95 years) were identified. Thirty-five percent of patients (17 of 48) had SC and 65% (31 of 48) had SE. SE was nonconvulsive in 10 (32%), convulsive in 11 (36%), and focal in 10 (32%) patients. SE was acute symptomatic in six (20%) and remote symptomatic in 11 (35%) patients. Fourteen (45%) had preexisting epilepsy. Median initial bolus dose was 200 mg (range 200-400 mg) in patients with SE and 200 mg in patients with SC. Maximum infusion rate was 60 mg/min. Cessation was observed in 42 patients (88%). Success rate in patients with SE receiving LCM as first or second drug was 100% (8 of 8), as third drug 81% (11 of 15), and as fourth or later drug 75% (6 of 8). There were no side effects observed except for pruritus and skin rash in two patients. These data support use of IV LCM as a potential alternative to standard antiepileptic drugs for acute treatment of seizure emergency situations, although randomized controlled studies are needed.
    No preview · Article · Jul 2011 · Epilepsia
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    ABSTRACT: Cranial nerves (CNs) crossing between the brainstem and skull base at the level of the tentorial hiatus may be at risk in temporomesial surgery involving subpial dissection and/or tumorous growth leading to distorted anatomy. We aimed to identify the surgical steps most likely to result in CN damage in this type of surgery. Electromyographic responses obtained with standard neuromonitoring techniques and a continuous free-running EMG were graded as either contact activity or pathological spontaneous activity (PSA) during subpial resection of temporomesial structures in 16 selective amygdalohippocampectomy cases. Integrity of peripheral motor axons was tested by transpial/transarachnoidal electrical stimulation while recording compound muscle action potentials from distal muscle(s). Continuous EMG showed pathological activity in five (31.2%) patients. Nine events with PSA (slight activity, n = 8; strong temporary activity, n = 1) were recorded. The oculomotor nerve was involved three times, the trochlear nerve twice, the facial nerve once, and all monitored nerves on three occasions. Surgical maneuvers associated with PSA were the resection of deep parts of the hippocampus and parahippocampal gyrus (CN IV, twice; CN III, once), lining with or removing cotton patties from the resection cavity (III, twice; all channels, once) and indirect exertion of tension on the intact pia/arachnoid of the uncal region while mobilizing the hippocampus and parahippocampal gyrus en bloc (all channels, once; III, once). CMAPs were observed at 0.3 mA in two patients and at 0.6 mA in one patient, and without registering the exact amount of intensity in three patients. The most dangerous steps leading to cranial nerve damage during mesial temporal lobe surgery are the final stages of the intervention while the resection is being completed in the deep posterior part and the resection cavity is being lined with patties. Distant traction may act on nerves crossing the tentorial hiatus via the intact arachnoid.
    Full-text · Article · Mar 2011 · Acta Neurochirurgica
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    ABSTRACT: 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. We retrospectively evaluated 596 video-EEG sessions in 507 patients (233 men, mean age 36 years, standard deviation = 14, range 9-80 years) within a 6-year period. AEs were examined in detail and their risk factors were assessed using multiple logistic regression analysis. Key Forty-four patients (9%) experienced 53 AEs: 20 had psychiatric events (17 postictal psychosis, 2 panic attacks, 1 interictal psychosis), 15 had injuries (14 falls with minor injuries, 2 falls with fractures, 2 fractures without fall, 1 fall with epidural hematoma), 10 patients had 13 episodes of status epilepticus (SE), and one AE was treatment-related (valproic acid--induced encephalopathy). Patients with AEs were older (p = 0.036) and had a longer duration of epilepsy (p = 0.019). All AEs resulted in a prolonged hospital stay (p < 0.001). Ninety-one percent of the AEs occurred within the first 4 days of monitoring. Independent risk factors were duration of epilepsy >17 years [odds ratio (OR) 3.096; 95% confidence interval (CI) 1.548-6.189], a previous history of psychiatric illness (OR 16.882; 95% CI 5.469-52.110), a history of seizure-related injuries (OR 3.542; 95% CI 1.069-11.739), or a history of SE (OR 3.334; 95% CI 1.297-8.565). Significance:  The most common AEs were postictal psychosis, falls, and SE. Patients with an older age, long disease duration, psychiatric comorbidity, history of injuries, and SE have a higher risk.
    Full-text · Article · Nov 2010 · Epilepsia
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    ABSTRACT: Hippocampal abnormalities may coexist with malformations of cortical development (MCD). This cross-sectional MRI study aimed at categorizing hippocampal abnormalities in a large group of MCD and comparing MCD patients with (group W) and without (group W/O) hippocampal abnormalities. Hippocampal anatomy, rotation, size, internal structure, and MRI signal alterations were assessed visually by 3 independent raters in patients with MCD and epilepsy. Four types of hippocampal abnormalities were examined in 220 patients (116 women, mean age 31 +/- 16.6, range 2-76 years): partially infolded/hypoplastic hippocampus (HH), hippocampal sclerosis (HS), malrotated hippocampus (MH), and enlarged hippocampus (EH). The commonest MCD in the cohort were focal cortical dysplasia (27%), polymicrogyria (PMG) (21%), developmental tumors (15%), and periventricular nodular heterotopia (PNH) (14%). Hippocampal abnormalities were seen in 69/220 (31%) patients: HH in 34/69 (49%); HS in 18/69 (26%); MH in 15/69 (22%); and EH in 2/69 (3%). PNH (21/30 [70%]) and PMG (22/47 [47%]) were most commonly associated with hippocampal abnormalities. Compared to the W/O group, patients in the W group had a higher rate of learning disability (W 41/69 [59%] vs W/O 56/151 [37%]; p = 0.003) and delayed developmental milestones (W 36/69 [52%] vs W/O 53/151 [35%]; p = 0.025); groups did not differ otherwise with regard to clinical presentation. HH was associated with symptomatic generalized epilepsies (11/34 [32%]) and high rate of learning disability (27/34 [79%]), neurologic deficits (25/34 [73%]), and delayed developmental milestones (23/34 [68%]). About a third of patients with malformations of cortical development had hippocampal abnormalities. Patients with hypoplastic hippocampus had the most severe clinical phenotype.
    No preview · Article · May 2010 · Neurology

  • No preview · Conference Paper · Dec 2009
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    ABSTRACT: To 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. The 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. The presurgical evaluation extended over 21.2 months (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. The 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.
    Full-text · Article · Dec 2009 · Acta Neurochirurgica

Publication Stats

440 Citations
122.94 Total Impact Points

Institutions

  • 2010-2015
    • Paracelsus Medical University Salzburg
      Salzburg, Salzburg, Austria
  • 2005-2014
    • University of Innsbruck
      • Institute of Biochemistry
      Innsbruck, Tyrol, Austria
  • 2007
    • Medizinische Universität Innsbruck
      • Department of Neurology
      Innsbruck, Tyrol, Austria
  • 2002
    • Landeskrankenhaus - Universitätskliniken Innsbruck
      Innsbruck, Tyrol, Austria