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Biomedical subjects

M Feucht

Publications and source records attributed to M Feucht.

At least 19 recordsLinked to original sources
PubMed2006

Spacial perception and spatial memory in children with benign childhood epilepsy with centro-temporal spikes (BCECTS).

Despite the benign prognosis regarding the response of seizures to treatment, some evidence now exists that patients with benign childhood epilepsy with centro-temporal spikes (BCECTS) may have neuropsychological deficits sometimes leading to academic underachievement. There is, however, no general agreement on the exact profile of functions disturbed. This study was designed to identify significant deficits in spatial perception and memory in children with BCECTS (ages 6-10 years) compared with healthy controls matched for age, sex and socioeconomic status. The neuropsychological test battery administered consisted of the HAWIK-III, the "Tübinger Luria Christensen Neuropsychological Test Set for Children", the "Kaufman Assessment Battery for Children" and the "Differential Neuropsychological Test". Twenty-two patients and 22 control subjects completed all tests. Children with BCECTS exhibited significant deficits in higher functions of spatial perception, including spatial orientation, as well as in basal and complex spatial memory. Deficits were independent of the lateralization of the epileptogenic foci and independent of anti-convulsive drug treatment.

Case-Control Studies↗
PubMed2006

[Status of TTT in the therapy for CNV].

Transpupillary thermotherapy (TTT) and photodynamic therapy (PDT) are recent treatment options for choroidal neovascularisation (CNV). In PDT a photochemical reaction is induced by the injection of a photosensitising substance. In contrast to this, TTT is a non-invasive photothermal treatment option for CNV and choroidal tumours. It leads to a low-grade-hyperthermia with consecutive induction of metabolic processes and production of heat-shock proteins in order to restore cellular homeostasis. Classical laser coagulation as recommended by the Macular Photocoagulation Study Group produces a photocoagulative effect with significant tissue hyperthermia and prompt visual loss. For classic CNV, PDT represents an established therapy option. Positive results of the treatment of occult CNV by PDT have enlarged the use of PDT to this kind of CNV. TTT represents an economic therapy modality for (mainly) occult CNV. The effect for visual outcome varies in different studies. The results are shown in a .

Choroidal Neovascularization↗
PubMed2005

[Development of an epiretinal prosthesis for stimulation of the human retina].

Degenerations of the outer retina in retinal diseases such as retinitis pigmentosa lead to blindness due to photoreceptor loss. A therapeutic option for visual rehabilitation is presently not available. Over the last few years, a retinal prosthesis has been developed and its use has been tested in animal experiments as well as in humans. With the epiretinal implant images of the environment are taken by a camera, these data are transmitted to an intraocular encoder, and the retina is electrically stimulated by a retinal stimulator placed epiretinally. The stimulation electrodes are placed as flexible microcontact electrodes by pars plana vitrectomy in an epimacular position. The threshold is determined by stimulations of increasing amplitudes. Initial results of acute epiretinal stimulation using an epiretinal implant in legally blind patients demonstrate that acute epiretinal stimulation of the human retina is feasible and safe.

Animals↗
PubMed2005

[NF2: ocular, neural and genetic manifestations].

Neurofibromatosis 2 is an autosomal-dominant disease, which is characterized by vestibular schwannomas, cataract, retinal hamartomas as well as tumors of the peripheral and central nerve system, demonstrating a variety of expression. The ophthalmologist plays an important role in making the diagnosis, as several ocular manifestations may be shown during childhood, before tumors of the central nerve system become symptomatic. An early diagnosis of NF 2 may prevent deafness by early surgical intervention. Due to primary and secondary reasons such as age-related processes, different sensations like hearing or vision may be compromised. Neuropathy may lead to vestibular disturbances and loss of muscle control. Therapeutic options include cataract surgery, implantation of cochlear or brainstem implants as well as conservative therapy of the ocular surface in paresis of the VIIth cranial nerve or learning to read from the lips. The human NF2 gene was cloned from chromosome 22 in 1993. The major part of the genetic alterations described so far are point mutations as well as deletions or insertions in or around the exons. Geno-phenotype correlations allow some predictions of the course of the disease to be made.

Adolescent↗
PubMed2004

EKG abnormalities in children and adolescents with symptomatic temporal lobe epilepsy.

BACKGROUND: Changes in cardiac rate and rhythm are often found in adult patients with temporal lobe epilepsy (TLE) and could be involved in the pathogenesis of sudden unexplained death (SUDEP). However, little is known about heart rate (HR) variability in pediatric patients with TLE. OBJECTIVES: To investigate ictal and peri-ictal HR abnormalities in children and adolescents with medically refractory symptomatic TLE and to determine the influence of focus localization and laterality. METHODS: Patients younger than 18 years, with drug-resistant unilateral symptomatic TLE and presenting with at least one habitual complex partial seizure (CPS) during presurgical noninvasive video-EEG monitoring, were enrolled. Synchronous single-channel EKG recordings were analyzed during the preictal, ictal, and postictal stages. RESULTS: Twenty patients fulfilled the inclusion criteria. Seventy-two temporal lobe seizures (TLSs) were analyzed. Ictal tachycardia was found in 71 TLSs (98%), whereas ictal bradycardia was not observed. During preictal stages, tachycardia occurred in 20 seizures and mild bradycardia in 3. In 44 seizures (62%), tachycardia was still present >60 seconds after EEG seizure termination. Cluster analysis revealed significant differences in HR evolution depending on location and side of seizure onset: Early and high HR increase was primarily associated with right mesial TLSs. CONCLUSIONS: Cardiovascular dysregulation is common during temporal lobe CPSs in children. These results confirm a right hemispheric lateralization of sympathetic cardiac control.

Adolescent↗
PubMed2004

[Transpupillary thermotherapy for subfoveal choroidal neovascularization. A 9-month follow-up].

PURPOSE: The purpose of this study was to evaluate the efficiency, stability, and safety of transpupillary thermotherapy as a treatment of subfoveal occult choroidal neovascularizations (CNV) in age-related macular degeneration. METHODS: Transpupillary thermotherapy (TTT) was performed in 40 patients with uni- or bilateral predominantly occult CNV. Laser light derived from an infrared diode laser at 810 nm was used to apply spots for a duration of 60 s. A complete ophthalmic examination was performed prior to and 9 months after the treatment. RESULTS: After 9 months, visual acuity remained stable in 65% (+/-2 lines). In 35% of the patients TTT could not prevent further visual loss. Retinal leakage, assessed by fluorescein angiography, stabilized in 67.5% of the treated patients. CONCLUSIONS: The present data show stabilization of visual acuity in 65% after TTT. Compared to the natural course of occult and mixed subfoveal CNV, these data give some evidence for patient benefit after TTT.

Aged↗
PubMed2003

Glatiramer acetate treatment in patients with childhood and juvenile onset multiple sclerosis.

BACKGROUND: Recent data indicate that in multiple sclerosis disease onset before the age of 16 is more common than previously assumed. However, current therapeutic options are limited to the treatment of acute attacks in these patients. Glatiramer acetate has been successfully applied in adults with relapsing-remitting multiple sclerosis, but there are no data available about the use of glatiramer acetate in childhood and juvenile onset multiple sclerosis. METHODS: Seven patients with relapsing-remitting multiple sclerosis and disease onset between 9 and 16 years of age were treated with daily subcutaneous injection of 20 mg glatiramer acetate (Copaxone). Patients were followed for 24 months. Treatment was initiated in all patients before the age of 18. RESULTS: The use of glatiramer acetate in our cohort of early onset multiple sclerosis patients was safe and well tolerated. Two out of seven patients remained relapse-free during the two year period. Clinical disability as measured by the EDSS remained stable in three out of seven patients. CONCLUSION: Due to the small number of patients the efficacy of the treatment has to be interpreted with caution. However, there might be a more pronounced treatment benefit in patients with low disability at treatment initiation and early treatment onset.

Adjuvants, Immunologic↗
PubMed2001

Identification of the stimulated hemiretina in primary school children and adults based on left and right hemifield pattern reversal visual evoked potentials--a comparative study.

OBJECTIVES: The analysis of left and right hemifield pattern-reversal visual evoked potentials (PVEPs) in children and the identification of the stimulated hemiretina testing different identification procedures previously applied to adults. METHODS: Lateral hemifield PVEPs were recorded in 40 children (6-11 years) and 27 adults (25-40 years) from, at least, 19 standard electrodes. Two procedures were tested for the determination of the stimulated hemifield: firstly, the evaluation of the values of instantaneous frequency at the occipital electrodes at P100 latency (determined by the global field power), and secondly, the application of a generalised dynamic neural network (GDNN) using the PVEP time course at selected electrode positions as the external input. RESULTS: P100 latency as well as P100 amplitude over the contralateral occiput in children were significantly greater than in adults. Contrary to the behaviour in adults, instantaneous frequency is not a robust identifier of left and right hemiretina stimulation in children. The best identification performances were achieved when using group trained GDNNs with the bipolar difference signals of electrodes P3/P4 or T5/T6 as the external input. CONCLUSIONS: The PVEPs at electrodes P3/P4 and T5/T6 contain essential information for the determination of the stimulated hemifield. This should be further considered during the development of on-line procedures for automatic PVEP detection in future studies.

Adult↗
PubMed2000

Ictal urinary urge indicates seizure onset in the nondominant temporal lobe.

The authors describe six patients with medically refractory temporal lobe epilepsy whose seizures were characterized by an aura of ictal urinary urge. All seizures originated in the nondominant temporal lobe as evidenced from interictal spikes, ictal EEG, and MRI. Ictal SPECT, which was obtained in two patients, showed a hyperperfusion of the insular cortex, indicating a critical role of the insula for the generation of this symptom. Ictal urinary urge represents a new lateralizing sign indicating a seizure onset in the nondominant temporal lobe.

Adolescent↗
PubMed1999

Possible association between childhood absence epilepsy and the gene encoding GABRB3.

BACKGROUND: Childhood Absence Epilepsy (CAE) is considered to have a predominantly, perhaps exclusively, genetic background. To date, genes responsible for susceptibility to CAE have not been identified. The object of the present study was to test association between CAE and the genes encoding the gamma-aminobutyric acid (GABA) type-A receptor subunits alpha 5 (GABRA5) and beta 3 (GABRB3) located on the long arm of chromosome 15 (15q11-q13). METHODS: A family-based candidate gene approach was applied: 50 Austrian nuclear families ascertained for the presence of an affected child were investigated. GABRA5 and GABRB3 subunit genes were genotyped using DNA gained from peripheral blood samples by Polymerase Chain Reactions (PCR). Genetic association was tested using a Monte Carlo Version of the multi-allele Transmission-Disequilibrium Test (TDT). RESULTS: The TDT displayed significant overall association with GABRB3 (p = .0118). CONCLUSIONS: The present data suggest that the tested polymorphism may be either directly involved in the etiology of CAE or in linkage disequilibrium with disease-predisposing sites.

Adolescent↗
PubMed1999

Application of correlation dimension and pointwise dimension for non-linear topographical analysis of focal onset seizures.

For many patients who are candidates for epilepsy surgery, non-invasive evaluation fails to provide sufficient information to permit surgical treatment. Since there are also definite risks and considerable costs associated with invasive procedures, new (non-invasive) techniques are required. This study provides empirical evidence that a non-linear approach applied to ictal surface electroencephalograms (EEGs) can help to delineate the area of seizure onset and may prove useful in complementing visual analysis of the EEG. Multichannel EEGs, recorded from eight patients with different drug-resistant localisation-related epilepsies, were analysed using the concept of correlation dimension and two extensions based on the pointwise dimension. The latter also provided results in cases where assessment of the correlation dimension was not feasible. Comparative values between 2 and 6 were accepted as the result of the algorithms, mostly 3-4 for the EEG channels strongly reflecting epileptic activity, and 4-6 for the other signals. The proportion of accepted pointwise values was usually 200-800% for strong epileptic EEG activity compared to the other data. The approach permitted the characterisation of the scalp area reflecting epileptic activity. The results obtained were in perfect concordance with those obtained during pre-surgical work-up and confirmed by the post-operative outcome.

Adolescent↗
PubMed1998

Paracrine and autocrine regulation of vascular endothelial growth factor during tissue differentiation in the quail.

The expression of vascular endothelial growth factor (VEGF) has been described to coincide both temporally and spatially with angiogenesis suggesting a role as a paracrine stimulator of endothelial cells. We have used digoxigenin labelled RNA probes to VEGF and the VEGF receptor-2 (Quek1) to investigate the relationship between VEGF expression and vascular events in quail embryos from day 1 to 13 of incubation. Furthermore, the effect of exogenously applied VEGF was studied in day 4 quail embryos using polyclonal anti-VEGF antibodies. Expression of VEGF mRNA was observed in day 1 and 2 embryos in regions of active angiogenesis and hemangiopoiesis. VEGF mRNA expression was found at high levels in the ventral aspect of the neural tube and Quek1 mRNA expression in the accompanying endothelial cells of day 3 embryos, suggesting a function in brain angiogenesis. However, in the neural tube, thyroid gland and cartilaginous skeleton VEGF mRNA was expressed at least 1 day before the ingrowth of vessels, suggesting that additional mechanisms are involved in control of angiogenesis. This is supported by the observation that application of VEGF165 into the midbrain induced dilatation of perineural vessels, while the intraneural vessels remained almost unaffected. Expression of VEGF mRNA was also observed at high levels in podocytes during all stages, indicative of its importance in glomerular development and function. The results of the present study indicate that as angiogenesis occurred in other tissues and organs (day 13 metanephros, dorsal third of the day 7 neural tube, skeletal muscle, and many mesodermal compartments), there was concurrent paracrine expression of VEGF mRNA and Quek1 mRNA. One noteable exception was the hepatocytes of the developing liver which appeared to remain VEGF-negative throughout the study. However, a small number of endothelial cells within liver sinuses, and additionally within the kidney and the elastic arteries, expressed VEGF mRNA. These results suggest that VEGF may also act as an autocrine mediator of angiogenesis, possibly as a result of localised tissue hypoxia.

Animals↗
PubMed1998

Nonlinear dynamics of 3 Hz spike-and-wave discharges recorded during typical absence seizures in children.

One-channel routine recordings of the scalp electroencephalogram (EEG) from unmedicated children strictly classified as unprovoked typical (3 c/s) absence seizures were selected. The dynamics of spike-and-wave discharges (SWD) were then examined by means of autocorrelation, correlation dimension, averaged pointwise dimension and largest Lyapunov exponent. For one EEG signal with pronounced spike-and-wave (SW) patterns, these measures were used complementary to a surrogate data method, a nonlinear (SETAR) modeling approach, and a SW simulation procedure providing five types of SW test signals. The SETAR model exhibited stationary SW dynamics, visually very similar to the EEG target signal, and with clear nonlinear structure. According to the results, the EEG episodes investigated represent low-dimensional dynamics, possibly recorded during nonstationary periods. Arguments that justify the assumption of deterministic chaos in our EEG signals were not obtained with the current methods. From the results one may conclude that two global oscillatory modes are present for the model, and three modes are active during the EEG recording period.

Algorithms↗
PubMed1997

Simultaneous spike detection and topographic classification in pediatric surface EEGs.

In this study, an algorithm is introduced for the automatic detection and simultaneous topographic classification of interictal regional spike activity in pediatric surface EEG records. The algorithm is based on the classification of the topographic distribution of instantaneous power by means of a 'group' trained classifier. The results of automatic spike analysis were compared with the decisions of two experienced electroencephalographers. Four routine EEG records exhibiting (multi)regional spikes were examined. The mean selectivity for the automatic spike detector was 84.6% (mean sensitivity 88.1%, mean specificity 89.3%) and for the electroencephalographers 85.3%. All spikes detected by the algorithm were simultaneously classified according to their topographic characteristics. The results of automatic spike classification (lateralization/localization) corresponded to the results of visual analysis.

Algorithms↗
PubMed1997

[Presurgical diagnosis of epilepsy and surgical epilepsy treatment].

20% of patients with focal epilepsy suffer from medically refractory seizures. Many of these patients can be cured by a surgical intervention removing the brain area where the seizures are originating (epileptogenic zone). 6000 patients in Austria would benefit from epilepsy surgery with an additional 150-200 new patients appearing each year. Potential candidates have to undergo an extensive presurgical work-up. During the non-invasive Phase I each patient is evaluated with an intensive video-EEG monitoring with scalp-EEG, a high resolution MRI, a SPECT and/or PET, a neuropsychological evaluation and a Wada-test. If the epileptogenic zone cannot be localized adequately with these methods, invasive electrophysiological techniques (epidural Peg-electrodes, Foramen-ovale electrodes, depth electrodes, subdural strip and grid electrodes) have to be applied. Operative strategies for temporal lobe epilepsies include antero-mesial temporal lobe resections and selective amygdala-hippocampectomies. Extratemporal epilepsies are treated by cortical resections guided by structural and electrophysiological parameters. The new technique of multiple subpial transections facilitates treatment of seizures originating in essential brain regions. Catastrophic epilepsies of early childhood often are caused by extensive pathologies affecting one hemisphere and can be treated successfully by large multilobar resections or hemispherectomies. Epilepsy surgery renders 70-80% of patients seizure free and thus can be regarded as an effective and safe treatment option for patients with medically refractory focal epilepsies.

Brain Diseases↗
PubMed1997

VEGF induces cardiovascular malformation and embryonic lethality.

The essential function of vascular endothelial growth factor (VEGF) in embryonic angiogenesis has clearly been documented in murine embryos with targeted deletions of either VEGF or its receptors. The effects of VEGF in the organogenetic phase of development have not been studied to date. Therefore, we applied 0.7 to 0.9 microgram of VEGF via methylcellulose carriers into the midbrain or onto the right forelimb of 4.5-day-old quail embryos. Another group of embryos was treated with 1 microgram of platelet-derived growth factor and controls were carried out using carriers without any growth factor. VEGF-induced cardiovascular malformations resulted in embryonic lethality. The venous area of the vasculature was dilated in almost all organs. The heart was most seriously affected and showed typical characteristics of insufficiency. VEGF strongly increased endocardial cell proliferation and obviously induced impairment of the growth rates of myocardium and endocardium. The myocardium of the ventricles was extremely thin, and septation defects were observed. As a result of the disturbed outflow, the atria were extremely dilated and thin-walled. The morphology of the hearts was reminiscent of that observed in congenital malformations such as Uhl's and Osler's syndromes. Our results show that expression of VEGF has to be tightly controlled during development.

Animals↗
PubMed1996

Analysis and classification of interictal spike discharges in benign partial epilepsy of childhood on the basis of the Hilbert transformation.

The spatial distribution of instantaneous power during the occurrence of rolandic spikes (computed via Hilbert transformation) can be utilized for classification of topographically different spike types. By visual analysis of the instantaneous power maps we found seven characteristic spike classes which correspond to the results of visual analysis of potential distribution. A neural network (NN) was trained with representatives of these classes. Single instantaneous power maps of 55/56 visually selected rolandic spikes, as well as map sequences of averaged spike segments (on-line) of 17 patients, were correctly classified by means of NN. The sensitivity of the NN for spikes from unknown patients was 98%. The classification scheme enables an objective classification of (multi-) regional spikes for selective averaging and for studies dealing with syndrome classification.

Child↗