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Biomedical subjects

H Stefan

Publications and source records attributed to H Stefan.

At least 145 records · Page 8Linked to original sources
PubMed1992

[Etiology, follow-up and therapy of seizure clusters in temporal lobe epilepsy and catamenial epileptic seizures].

The phenomenon of seizure clustering is still poorly understood. We therefore investigated 192 patients with temporal lobe epilepsies among whom 60 showed clustering of seizures. The percentage of women was significantly higher in the cluster than in the non-cluster group, the history of epilepsy lasted longer and the excess of complex partial seizures over tonic clonic seizures was more prominent in the cluster group. In 46 out of the 60 patients the clustering did not occur initially but developed in the course of the disease. In a particular subgroup the development initiated with isolated tonic clonic seizures, in a later phase complex partial seizures appeared and finally only complex partial seizures remained. This type of history was found significantly more frequent in the cluster than in the non-cluster group (27% versus 7%). It is conjectured that endogenous, as well as exogenous factors, both of them not completely revealed, cause the occurrence of clusters; anticonvulsant drug therapy might even enlarge this trend. Patients with seizure clustering tend to be pharmacoresistant. Chronic therapy with antiepileptic drugs besides intermittent therapy with benzodiazepines may help. A particular type of seizure clustering is observed in catamenial epilepsies where seizures appear in the perimenstrual and/or periovulatory phase of the menstrual hormonal cycle of females. This type of seizure incidence is obviously influenced by hormonal rhythms. Ten patients suffering from catamenial epileptic seizures were therefore treated with a synthetic analogue of GnRH in order to suppress the menstrual hormonal rhythm. As a result 3 patients became seizure free and in 5 patients seizure frequency decreased.

Adolescent↗
PubMed1992

Endoscopic retrograde cholangiopancreatography in childhood.

ERCP was performed in 19 children and adolescents aged 4 to 16 years. In 13 children the examination was done under general anesthesia, in 6 cases with the usual premedication using dolsin and atropine. Indications for examination were unclear abdominal pain with occasional amylase elevation, in 3 patients status after an abdominal injury. In 16 patients the examination clarified the complaints by detecting organic disease of the gallbladder or the pancreas. ERCP is an important procedure in the event of uncertain diagnosis in children and adolescents and, if the indication is correct, and the technique good, is well tolerated by the patients.

Abdominal Pain↗
PubMed1992

[Esophageal replacement using the large intestine in children].

Oesophageal replacement with an interposed graft of the large intestine on a vascular pedicle between the cervical oesophagus and oesophageal stump over the diaphragm was performed in four children for Vogt's classification Type-I and II oesophageal atresia. A tracheooesophageal fistula was closed in three, and gastrostomy was established in four neonates to provide nutrition. Oesophageal replacement was performed in patients aged 2 years and 5 months to 5 years and 4 months. One girl died following oesophageal replacement for bilateral pneumonia. A non-functioning oesophageus was extirpated for corrosive oesophageal stricture with simultaneous replacement by means of colonoplasty in two boys aged 3 1/4 years and 3 1/2 years. As regards complications, a shortly persisting salivary fistula developed in the cervical anastomosis, and an abundant graft was made shorter and a fundoplication for gastrooesophageal reflux was established in the same patient. To prevent leakage of the anastomosis and its stricture, the anastomoses were constructed obliquely and sutured in two layers using thin atraumatic suture with silk thread. The patients have been on follow-up for 3 to 12 years (mean 6.5 years) after oesophageal replacement; their ability to swallow, psychosomatic development and surgical criteria were employed to evaluate the outcome as excellent in four, and good in one of the children operated on.

Child, Preschool↗
PubMed1991

[Rise in serum prolactin concentration after frontal lobe seizures. Possibilities in differential diagnosis of psychogenic seizures].

The prolactin concentration profile over 24 hours was determined in three men, aged 19, 27 and 43 years, who suffered from treatment-resistant complex-partial and (or) grand mal seizures of frontal lobe origin. All three patients were examined in the course of preoperative epilepsy diagnosis, the seizures being classified by video-EEG recordings, including subdural and sphenoidal foramen ovale electrodes. Seizures were recorded in all three patients (4 grand mal; 2 complex-partial), each of them followed by a rise in serum prolactin concentration (over 700 microU/ml). These findings contradict the theory that prolactin concentration rises only after temporal, not after frontal seizures. Knowing the postseizure serum prolactin concentration may help to distinguish frontal epileptic from psychogenic seizures.

Adult↗
PubMed1991

Blindness as an ictal phenomenon: investigations with EEG and SPECT in two patients suffering from epilepsy.

Blindness is a rare ictal phenomenon in epileptic seizures. It can occur as an aura, as the seizure itself, or postictally. We investigated two such patients, in one of whom blindness manifested as an aura prior to tonic clonic seizures; the interictal EEG exhibited a spike-wave focus bioccipitally. In the second patient blindness occurred postictally. An ictal SPECT, carried out at the onset of the seizure demonstrated marked hyperperfusion in both occipital regions.

Adult↗
PubMed1991

The neocortico to mesio-basal limbic propagation of focal epileptic activity during the spike-wave complex.

In order to localize epileptogenic electrophysiological sources, a multichannel MEG system was used in 3 patients with partial epilepsy during presurgical evaluation. MEG and EEG (including scalp, sphenoidal and intracranial foramen ovale electrodes) were recorded simultaneously during a period of intensive video-EEG monitoring in order to observe single spontaneous spikes. In addition to MRI, SPECT and PET investigations were performed. Electrical activity subsequent to the activity of the epileptic focus could be localized by the MEG after noise reduction using a temporal correlation technique. Simultaneous registration of the magnetic field and the electrical field showed that the source of the primary focal epileptic activity (first period during the total spike wave complex where a dipolar magnetic field pattern is found) is localized in neocortical lateral regions, whereas another focal epileptic activity in a later phase of propagation occurs in temporal mesial regions. In 1 patient (case 1) the primary focal epileptic activity was localized in the surrounding neocortical tissue of an angioma and the middle and inferior temporal gyrus. The second phase of propagation is localized in temporo-basal-mesial regions, including para- and hippocampal structures. The latest center of activity occurred in posterior parts of the gyrus cinguli. In 2 other patients, the primary focal epileptogenic activity was localized at the insula and also spread into temporal basal mesial regions. A multi-modal approach to research of focal epilepsy, combining metabolic, electrical potential, magnetoencephalographic and morphological data, recorded by non-invasive techniques, offers new perspectives for the detection of involved brain regions. The 3-D and time-resolved localization of focal epileptic activity, correlated with the individual anatomy of the human brain, may improve the determination of neuronal populations involved in the individual epileptogenic process, especially in the interaction between temporal or extratemporal neocortex and limbic system.

Adult↗
PubMed1991

[Craniocerebral trauma and glioma].

There are only a few well documented cases in the literature which allow for the assumption of traumatic origin of some intracranial tumors. Four cases are presented in whom the authors have accepted the traumatic origin of gliomas because of it's evidence, but--from their scientific understanding of tumor development--without being convinced of such a correlation. It is stressed that scientific points of view and argumentation in social insurance affairs may differ and that they should be carefully distinguished.

Adult↗
PubMed1991

Electrocorticography in temporal lobe epilepsy surgery.

The results of intra-operative cortical EEG recordings (ECoG) were assessed in 30 patients with medically refractory complex partial seizures submitted to temporal lobectomy. Interictal spiking was most frequently recorded from mesial temporal lobe structures (amygdaloid-hippocampal region) and from the temporal neocortex synchronously, as observed in 21/30 patients. In 7 patients, the interictal spiking involved the temporal neocortex exclusively. Electrical stimulation of mesial temporal lobe structures reproduced the patient's habitual warning in 10 patients. The results of this study confirms that ECoG provides reliable intra-operative mapping of the epileptogenic brain tissue to be excised.

Adolescent↗
PubMed1991

[4-Tesla 1H MR spectroscopy in patients with temporal lobe epilepsy].

7 patients with drug-resistant temporal lobe epilepsy (TLE) and localized EEG-focus were investigated with a 4 Tesla whole body MR-scanner. Proton (1H) magnetic resonance (MR) spectra were analyzed quantitatively and compared to the healthy side. MRS allowed the differentiation of the following metabolites in 5 patients: N-acetyl-aspartate (NAA), creatine and phosphocreatine, phosphorylcholine and glycerophosphorylcholine, beta- and gamma-glutamate (GLU). To compare the results with those of an already evaluated normal population, these metabolites were measured also in parietal region. The standard deviation was 42-46% in the patients. Unfortunately, in the temporal region, the field homogeneity was worse than parietal and thus the spectral analysis less distinct especially for GLU with a standard deviation of 45% for NAA and 66% for GLU on the healthy side. Thus, no significant findings were seen on focus side. There was only a tendency to an elevation of glutamate and a reduction of N-acetyl-aspartate.

Adolescent↗
PubMed1991

[Site and propagation of focal epileptic activity: multichannel MEG/EEG analysis].

Electrophysiological examinations provide the basis for a deeper pathophysiological understanding of focal epileptic activity. In addition to electroencephalography, magnetoencephalography from field measurements is now available for biomagnetic diagnosis. As magnetoencephalography (MEG) is basically better suited for the localization of focal epileptic activity than EEG, an increase in MEG measurements has taken place over the last years. In this study we discuss magnetic source localization which was combined with anatomical 3-D-MR-images and compared with the results of EEG-registration carried out simultaneously and with other investigative procedures of presurgical diagnosis. The results of investigation show that simultaneous magnetic field measurements over one hemisphere of the skull allow localization of sources both in the temporal lobe and in deeper areas of the brain. Furthermore, propagation of epileptic activity can be registered not only in neighbouring areas of the epileptogenic source but also in regions localized deeper in the temporal lobe. This opens new possibilities for presurgical evaluation as well as an understanding of partial and generalized epilepsies. The results of investigation show primary focal epileptic activity neocortex laterally or surrounding a mesio-temporal lesion in all investigated patients with partial (temporal, frontal) and secondary generalized epilepsies. Furthermore, a pattern of propagation of focal epileptic activity which is directed from neocortical-lateral to mediobasal-limbic brain structures is found in most of these patients.

Brain Diseases↗
PubMed1991

[Ictal and interictal 99mTc-HMPAO-SPECT studies in temporal lobe epilepsy with unilateral EEG focus].

Ictal and interictal SPECT measurements using 99mTc-HMPAO are helpful in localising an epileptic focus. 24 patients (12 women and 12 men; mean age 30 years) suffering from temporal lobe epilepsies with unilateral EEG foci were examined. In all patients a presurgical evaluation including sphenoidal and foramen oval electrodes was carried out. The analysis of SPECT measurement was done visually and semi-quantitatively, comparing the data with findings in healthy persons (10 women and 10 men; mean age 24 years). The etiology of the epilepsy was confirmed by histological investigation in 16 cases, and by CT and MRI in 8 cases. The findings were gliosis in 6 cases, astrocytoma in 3 cases, cysts in 4 cases, and angioma in 3 cases. In 8 cases no pathological findings could be detected. In 46% of cases interictal SPECTs exhibited a focal hypoperfusion corresponding with the EEG-focus. In ictal SPECTs this could be found in 75% of cases. In all 10 patients without morphological findings or with gliosis (proved by histological investigations) a hyperperfusion coincident with the EEG-focus appeared in ictal SPECTs.

Adolescent↗
PubMed1991

[Quantitative and qualitative MRI changes in temporal lobe epilepsy. A comparison with normal parameters of nuclear magnetic resonance tomography].

Magnetic resonance imaging (MRI) often reveals no pathology in patients with temporal lobe epilepsy (TLE) who are candidates for surgery, even though post-surgery histology reveals atrophy or sclerosis. To differentiate these pathologies in MRI, we performed a standardized acquisition and a quantitative analysis of MRI data (qMRI). The standard values of 43 healthy subjects (both sex, left and right handed) were compared with those of 10 patients with TLE and unilateral EEG focus. A reduced estimated total brain extension, a significant atrophy of both temporal lobes with accentuation on the focus side and a significant hippocampal atrophy on focus-side were seen even in patients with no visually detectable pathology. The analysis of the signal intensities did not give additional information. Thus, qMRI is a helpful additional tool in the course of presurgical evaluation for focus lateralization.

Adolescent↗
PubMed1990

[Surgical treatment of drug resistant epilepsy].

Even today, epilepsy is resistant to conservative treatment in a certain number of patients. In many of these cases surgical treatment is a meaningful alternative. The most important procedure is the resection of the epileptogenic focus. Thus, surgical treatment is only possible if the preoperative evaluation of the patient reveals a focus in a resectable area of the brain. In this article the modern electrophysiological, nuclear medical and neuroradiological diagnostic procedures, together with the various surgical procedures of surgery for epilepsy are presented.

Brain Mapping↗
PubMed1990

Regional cerebral blood flow during focal seizures of temporal and frontocentral onset.

Ictal single photon emission computed tomography recordings were performed in 9 patients in the course of 11 seizures. Injections of radionuclide were made an average of 72 seconds after the onset of the seizure as indicated by electroencephalography. All patients also underwent interictal recordings. In 6 patients, the localization of the electroencephalographic focus and the morphological lesions corresponded with the ictal hyperperfusion. This could be seen in single photon emission computed tomography. Seizures triggered by hyperventilation, and seizures of patients with anatomical brain lesions (e.g., cysts, surgical defects, and recent injections of technetium-hexamethylene-propylene-amine-oxime) showed an absent or noncorresponding localization of the ictal recording. The ictal and interictal recording seems suitable as a confirmatory noninvasive method for the localization of the epileptogenic focus, particularly in the preoperative evaluation of epilepsy.

Adolescent↗
PubMed1990

Pattern recognition in biomagnetic signals by spatio-temporal correlation and application to the localisation of propagating neuronal activity.

A combined correlation analysis of temporal and spatial patterns in a biomagnetic multichannel recording is proposed to extract patterns of transient, randomly repetitive physiological events from biomagnetic data sets with a low signal-to-noise ratio. This method is especially sensitive in the differentiation of signals from different source propagation pathways. The recognition and subsequent averaging of spike events in the MEG of an epileptic patient by this method is shown to provide an essential improvement in the signal-to-noise ratio. The source localisation from the averaged data showed electrical activity which propagated from the primary epileptogenic focus to distant parts of the brain.

Brain Mapping↗
PubMed1990

Magnetic source localization in focal epilepsy. Multichannel magnetoencephalography correlated with magnetic resonance brain imaging.

Initial results of magnetic source localization by means of multichannel recording using a 10 or a 31 channel system are reported. Simultaneous magnetoencephalographic (MEG) and electroencephalographic (EEG) (scalp, sphenoidal and foramen oval) recording, as well as magnetic resonance imaging (MRI) with a fixed head position, permits the projection of brain structures and the source localized from MEG into a three-dimensional coordinate system. From 8 patients investigated it can be clearly seen that the method is of diagnostic relevance for patients with temporal lobe epilepsy. Results are demonstrated for 3 patients with interesting findings concerning the anatomical correlation with source localization. The findings indicate that MRI-correlated magnetic source localization by means of multichannel recordings provides important advantages in epilepsy research. (1) Increased precision permits noninvasive localization. Deeper sources in the temporal lobe are localized from MEG combined with scalp or minor invasive EEG. (2) Investigation time is considerably shortened. (3) Single events can be localized for supplementary presurgical information concerning the three-dimensional anatomical localization of focal epileptic activity in the brain.

Adult↗