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H Stefan

Publications and source records attributed to H Stefan.

At least 55 records · Page 3Linked to original sources
PubMed2002

Sex differences and lateral asymmetry in heart rate modulation in patients with temporal lobe epilepsy.

This study was designed to study the influence of gender and lateral hemispheric asymmetry on heart rate modulation during temporal lobe seizures. Heart rate was recorded during complex partial seizures in 10 female and 11 male patients (12 with a right temporal lobe focus, nine with a left focus), with simultaneous video monitoring and bilateral subdural electrode placement. Heart rate changes were analysed during the seizure, at a time when the epileptic activity was restricted to one hemisphere. In this analysed interval, the heart rate of patients with a right temporal lobe focus showed a significant increase, from 73.5 to 91.0 beats/min (F = 10.7, df = 2.3/27, p < 0.001), while the heart rate of patients with a left sided focus only increased slightly, from 77.0 to 82.5 beats/min (NS). An effect of sex was demonstrated, in that the influence of focus laterality could only be shown in male patients (F = 14.24, df = 2.58/27, p < 0.001). These results confirm the right hemispheric lateralisation of sympathetic cardiac control in male patients.

Adult↗
PubMed2001

Ictal fear in temporal lobe epilepsy: surgical outcome and focal hippocampal changes revealed by proton magnetic resonance spectroscopy imaging.

BACKGROUND: Ictal fear (IF) is most frequently associated with epileptic discharges from mesial temporal areas. OBJECTIVES: To determine whether patients with IF were more likely to become seizure free after anteromesial temporal lobe resection compared with those without IF and whether they show more anteriorly pronounced metabolic changes assessed by means of multivoxel magnetic resonance spectroscopy (MRS) along the hippocampal axis. METHODS: Surgical outcome was assessed in 33 consecutive patients with temporal lobe epilepsy after a mean follow-up of 25 months (range, 12-38 months). Proton multivoxel MRS of the hippocampal formation was applied to detect regional differences along the axis of the hippocampus in patients with and without IF. Magnetic resonance tomography showed typical features of hippocampal sclerosis in all patients. RESULTS: Twelve (36%) of the 33 patients reported fear at the beginning of their habitual seizures. Eleven of these patients were seizure free postoperatively. In contrast, only 11 of 21 patients without IF had a favorable outcome. Results of MRS revealed significantly higher pathologic N-acetylaspartate-choline ratios in the anterior portion of the hippocampal formation in patients with than in those without IF, indicating focal metabolic and/or morphologic changes in the head of the hippocampus. CONCLUSIONS: These results indicate the importance of diagnosing auras with IF to provide a more detailed prognosis of the surgical outcome. In addition, our data emphasize that multivoxel MRS is a valuable tool in the presurgical evaluation, as it may reveal different topographical patterns of hippocampal sclerosis.

Adult↗
PubMed2001

[Diagnostic imaging in refractory temporal lobe epilepsy. A comparison of MR volumetry and multivoxel-MR-spectroscopy for assessment of postoperative prognosis].

While the importance of magnetic resonance (MR) spectroscopy, volumetry, and T2-relaxometry for preoperative localization has already been verified, the question arises as to what extent the individual techniques are useful for assessing postoperative prognosis with respect to seizures and neuropsychological outcome. In a prospective comparative study, 26 patients were examined preoperatively with a 1.5 T whole-body scanner. The MR spectroscopy was taken by high resolution 1 H proton spectroscopy, the volumetry with MP rage technique. The postoperative outcome was laid down using Engel's classification. Our results show that the metabolic changes can be divided into three groups using MR spectroscopy: unilateral, slightly bilateral, and severely bilateral to contralateral. In case of bilateral changes, the severity of metabolic changes in the nonoperated, contralateral side was decisive for postoperative outcome. The results from volumetry did not correlate with postoperative outcome.

Adult↗
PubMed2001

[Vagus nerve stimulation - a new option for the treatment of chronic pain syndromes?].

Electrical stimulation of the vagal nerve (VNS) has become an established method for treating medically refractory epilepsies. From animal experiments it is well known that depending on the stimulation intensity VNS can elicit both inhibition and facilitation of nociception. Recent physiologic investigations demonstrated a similar influence of VNS on pain perception in patients treated by chronic VNS. However, in humans, a more marked effect was shown for the pain inhibition which is probably mediated by neurobiochemical mechanisms. These findings are discussed in consideration of the physiologic mechanisms underlying the modulation of pain and seizures by VNS known from animal studies. First reports of attenuation of chronic pain by VNS indicate that the method might be an option for pain treatment in the future.

Animals↗
PubMed2001

Topiramate on ictal seizure semiology: a quantitative, randomized, low and medium dose-controlled study.

OBJECTIVE: Intensive and quantitative evaluation of the severity and frequency of seizures and ictal signs during topiramate (TPM) treatment. METHODS: Twenty patients with refractory partial seizures undergoing presurgical evaluation were randomized into a low dosage (100 mg daily) and a parallel medium dosage (200 mg daily) group of TPM add-on medication. Study phases included a 3-day baseline video-EEG phase, a 10-day TPM titration phase without video-EEG and a 3-day TPM dose maintenance phase with video-EEG. During the baseline and the dose maintenance phase seizures were recorded using video-EEG monitoring and the following parameters were measured: duration (lasting seconds of each seizure and ictal sign), intensity (on a 0-3 scale), N/24 h (numbers of attacks per 24 h), D/24 h (duration per 24 h) of both seizures and defined ictal signs. RESULTS: A total of 399 seizures during the baseline phase and the dose maintenance phase were intensively analyzed. Intergroup comparison suggested that duration, N/24 h and D/24 h of all seizures decreased more in the medium dosage group computing the reduction from baseline to the dose maintenance phase (P<0.05). There were statistically more significant reductions in the duration, intensity and N/24 h of ictal signs like hypermotoric movements, fumbling and vocalization in the medium dosage group (P<0.05). CONCLUSION: Topiramate has an early dose-dependent effect on ictal seizures. SHORT COMMUNICATION: The present study intensively analyzed the duration, intensity, N/24 h and D/24 h of ictal seizure manifestations. The quantitative data suggested that topiramate had an early effect on ictal phenomena like ictal hypermotoric movements, fumbling and vocalization (P<0.05); effects were more prominent in the medium dosage group (200 mg daily) than the low dosage group (100 mg daily).

Adolescent↗
PubMed2001

Therapeutic intensive seizure analysis (TISA) in presurgical evaluation of Losigamone.

OBJECTIVE: The new method TISA was used to evaluate Losigamone efficacy. METHODS: Sixteen patients with pharmacoresistant partial seizures undergoing presurgical evaluation were randomized in this double-blind, placebo-controlled, parallel-group Losigamone monotherapy study under continuous video-EEG monitoring. Duration (in s, of each seizure and each ictal sign), intensity (grade zero to three), N/24h (number of seizures and ictal signs per 24 h), D/24h (seconds per 24 h covered by seizures and ictal signs) and seizure free intervals were recorded. RESULTS: A total of 246 seizures were intensively analyzed. The duration and intensity of all seizures improved more in the active treatment group than in the placebo group. There was a statistically significant superiority in the duration of the seizure free interval in the Losigamone group. Ictal signs such as oro-alimentary automatisms and fumbling were improved during Losigamone treatment. CONCLUSION: Losigamone has a preferred inhibitory effect on propagated epileptic activity. TISA is a sensitive method for evaluation of the selective effects of AEDs.

Adult↗
PubMed2001

Recent advances in the diagnosis and treatment of epilepsy.

Recent advances in the diagnosis and treatment of epilepsies are discussed with special consideration of epidemiology and classification, progress in neuroimaging, electrophysiological studies using EEG and MEG, initiation of medical and surgical treatment, the role of new antiepileptic drugs and selected aspects of genetics of idiopathic epilepsies. In addition from conclusions obtained by the review of recent developments suggestions for future work in Europe are discussed. A constructive approach from multicenter studies requires homologous definitions, documentations and standardization of procedures of trials for European multicenter studies.

Anticonvulsants↗
PubMed2001

Magnetic resonance spectroscopy and histopathological findings in temporal lobe epilepsy.

PURPOSE: In some patients with temporal lobe epilepsy, histopathological evaluation of resected brain tissue after surgical treatment may reveal several features indicative of discrete cortical malformations. We sought to determine whether these histopathological features were accompanied by hippocampal changes detectable preoperatively by proton magnetic resonance (MR) spectroscopy and to evaluate their relationship with postoperative outcome. METHODS: In 25 consecutive temporal lobe epilepsy patients who were scheduled for surgical treatment, MR spectroscopy was performed, and resected brain tissue was analyzed histopathologically for the presence of discrete cortical malformations (e.g., microdysgenesis). Outcome was assessed in all patients with an average postoperative period of 26 months. RESULTS: In 13 patients, we found subtle, histopathologically detectable signs of cortical malformation: 6 of them with concomitant hippocampal sclerosis (dual pathology) and 7 without. The latter subgroup had a worse surgical outcome and showed enhanced bilateral and/or contralateral pathological changes in the hippocampal formation when investigated by MR spectroscopy. CONCLUSIONS: These data suggest that by showing contralaterally or bilaterally abnormal spectra, MR spectroscopy might be able to indicate pathological changes in subtle developmental disorders that are possibly more widespread over the brain. This observation may improve noninvasive diagnosis in presurgical evaluation and the neurobiological understanding of cortical malformations in pharmacoresistant temporal lobe epilepsy.

Adult↗
PubMed2001

Interictal cardiac autonomic dysfunction in temporal lobe epilepsy demonstrated by [(123)I]metaiodobenzylguanidine-SPECT.

We studied the post-ganglionic cardiac sympathetic innervation in patients with chronic temporal lobe epilepsy (TLE) by means of [(123)I]metaiodobenzylguanidine-single photon computed tomography (MIBG-SPECT) and evaluated the effects of carbamazepine on cardiac sympathetic innervation. TLE is frequently associated with dysfunction of the autonomic nervous system. Autonomic dysregulation might contribute to unexplained sudden death in epilepsy. Anticonvulsive medication, particularly with carbamazepine, might also influence autonomic cardiovascular modulation. MIBG-SPECT allows the quantification of post-ganglionic cardiac sympathetic innervation, whereas measuring the variability of the heart rate provides only functional parameters of autonomic modulation. Antiepileptic drugs, especially carbamazepine (CBZ), can affect cardiovascular modulation. We determined the index of cardiac MIBG uptake (heart/mediastinum ratio) and heart rate variability (HRV) using time and frequency domain parameters of sympathetic and parasympathetic modulation in 12 women and 10 men (median age 34.5 years) with a history of TLE for 7-41 years (median 20 years). Myocardial perfusion scintigrams were examined to rule out deficiencies of MIBG uptake due to myocardial ischaemia. To assess the possible effects of CBZ on autonomic function, we compared MIBG uptake and HRV in 11 patients who had taken CBZ and 11 patients who had not taken CBZ, and in 16 healthy controls. In order to identify MIBG uptake defects due to myocardial ischaemia, all patients had a perfusion scintigram. Cardiac MIBG uptake was significantly less in the TLE patients (1.75) than in the controls (2.14; P = 0.001), but did not differ between subgroups with and without CBZ treatment. The perfusion scintigram was normal in all patients. Time domain analysis of HRV parameters suggested the predominance of parasympathetic cardiac activity in the TLE patients, but less parasympathetic modulation in the patients treated with CBZ than in those not treated with CBZ (P < 0.05), whereas frequency domain parameters showed no significant difference between the subgroups of patients or between patients and controls. MIBG-SPECT demonstrates altered post-ganglionic cardiac sympathetic innervation. This dysfunction might carry an increased risk of cardiac abnormalities.

3-Iodobenzylguanidine↗
PubMed2000

Alteration of the somatosensory cortical map in peripheral mononeuropathy due to carpal tunnel syndrome.

Substantial plasticity of the mature mammalian somatosensory cortex was demonstrated after deprivation of sensory input produced by amputation or somatosensory deafferentation. Following transection of the median nerve, adult owl and squirrel monkeys exhibit extensive reorganization in the cortical representation of the hand in areas 3b and 1. In the present study we investigated the possible effect of incomplete median nerve damage on sensory cortex somatotopy in a patient with unilateral carpal tunnel syndrome. We assessed interhemispheric differences of the hand representation in SI by means of magnetic source imaging. Additional intersubject data comparison was performed for specific results on the basis of available normal data from the literature and from own investigations in five healthy volunteers. Our results demonstrated a decreased extension of the cortical zone representing the injured median nerve and suggested invasion of the deprived area by cortical sectors receiving inputs from the little finger (supplied by the ulnar nerve) and from the dorsum of the thumb (innervated by the radial nerve). The study indicates topographic rearrangement of the hand representational zone in the human primary somatosensory cortex in a case of chronic median nerve injury.

Aged↗
PubMed2000

Left vagus nerve stimulation suppresses experimentally induced pain.

OBJECTIVE: To test whether electric stimulation of the vagus nerve has an antinociceptive effect in humans. BACKGROUND: In a variety of animal studies, vagus nerve stimulation was shown to inhibit nociceptive behavior as well as electric responses of spinal nociceptive neurons. In humans, chronic left vagus nerve stimulation is used to treat pharmacologically refractory epilepsy. METHODS: The authors investigated experimental pain in 10 patients with seizures before and twice after implantation of a vagus nerve stimulator by using different controlled stimuli, including noxious heat, tonic pressure, and short impact. Pain was quantified on a visual analogue scale. Twelve nonepileptic age- and gender-matched individuals served as control subjects. RESULTS: Vagus nerve stimulation reduced increasing pain associated with trains of five consecutive stimuli at 1.5-second intervals ("wind-up"; p < 0.001). In a similar manner, pain on tonic pressure was reduced by vagus nerve stimulation (p < 0.03). Pain associated with single-impact stimuli as well as heat pain thresholds were unaltered under vagus nerve stimulation. Thus, vagus nerve stimulation led to pain relief predominantly in experimental procedures in which pain magnitude was amplified by central processing. The antinociceptive effect was independent of the acute on-off cycles of vagus nerve stimulation. CONCLUSIONS: Vagus nerve stimulation is effective in reducing pain in humans. In humans, the antinociceptive effect might rely on central inhibition rather than alterations of peripheral nociceptive mechanisms. These results indicate a promising, potential future role of vagus nerve stimulation in pain treatment.

Adult↗
PubMed2000

[MRI spectroscopy, T2 relaxometry, and postoperative prognosis in cryptogenic temporal lobe epilepsy].

The preoperative localization of pharmaco-resistant focal epilepsies before surgery and the prognosis concerning seizure outcome are both of importance. In addition to conventional MRI diagnostics for the detection of small epileptogenic lesions, proton magnetic resonance spectroscopic imaging (HMR spectroscopy) can be useful for assessing the bilaterality of pathological changes in cryptogenic temporal lobe epilepsies. The technique and findings of HMR spectroscopy are reported in patients with cryptogenic temporal lobe epilepsies. The findings indicate that chemical shift imaging (CSI) investigations of the ipsilateral and contralateral hemispheres provide important information for the prediction of seizure outcome after epilepsy surgery.

Adult↗
PubMed2000

[Drug therapy before and after surgery for epilepsy. Critical review and recommendations].

As a result of a critical review of the literature and a survey at German epilepsy centers of usual pre- and postoperative drug treatment, the following strategy is recommended: 1. Patients under consideration for surgery should be referred to specialists. Experience has shown that surgery is reasonable for only about a third of all patients with refractory epilepsies. The patient should first have been treated for at least 3 years with at least two first-line drugs in monotherapy and subsequent combined therapy. This applies only to medial temporal lobe epilepsies with very good postoperative prognoses. All other surgically removable epilepsy syndromes with less positive prognosis should be treated with additional antiepileptic drugs before any surgery. 2. There is no exception to the continuation of drug treatment after epilepsy surgery. If the patient remains free of seizures for at least 2 years, discontinuing the drug treatment can be discussed, just as with patients who are free of seizures due to drug treatment alone. In general, the less successful the operative therapy, the longer and more intensive the drug treatment.

Adult↗
PubMed2000

[Temporal lobe epilepsy: effect of focus side on the autonomic regulation of heart rate?].

Epileptic activity can modulate reactions of the autonomic nervous system. Although there is some evidence of a differential left/right hemispheric influence on the cardiovascular system, diverse investigations have shown controversial results. In our study, complex partial seizures of patients with temporal lobe epilepsy were recorded using subdural electrodes, thus providing reliable information on the focus side. We analyzed the preictal and ictal heart rates of 27 patients, 16 revealing right and 11 revealing left temporal foci. During the seizures, both groups showed a significant increase in heart rate. Preictal tachycardia was only significant in the right focus group, whereas no significant change in heart rates could be detected in the left focus group. Our results confirm a right hemispheric lateralization of sympathetic cardiac control.

Adult↗
PubMed2000

Progressive muscle pain, weight gain, fatique and unusual body shape change.

Multiple symmetrical lipomatosis (MSL) is a rare syndrome characterized by symmetric unencapsulated lipomas around the axial region and frequently associated with neurological involvement, particularly myopathy and neuropathy (Klopstock et al., 1994). Here we present a typical image of a patient with MSL, explaining this disease for neurologists who might care for these patients in an average day at the neuromuscular consultation unit.

Fatigue↗
PubMed2000

Magnetoencephalography in extratemporal epilepsy.

Epilepsy surgery candidates with extratemporal foci represent a particular diagnostic and therapeutic challenge, because of anatomic and functional features of the pertaining areas. In the last decade, novel developments in the field of electrophysiological techniques have offered new approaches to detailed localization of specific epileptic discharges as well as eloquent regions. Magnetoencephalography, in combination with neuroimaging data and simultaneously recorded EEG, yields promising results to clarify centers of epileptic activity and their relationship to structural abnormalites and functionally significant areas. Examples are given to illustrate the range of applications of this method as a contribution to routine presurgical evaluation.

Adolescent↗