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Biomedical subjects

S R Stodieck

Publications and source records attributed to S R Stodieck.

18 recordsLinked to original sources
PubMed1998

The photic driving EEG response and photoreactive cerebral blood flow in the posterior cerebral artery in controls and in patients with epilepsy.

OBJECTIVES: Instantaneous changes in blood flow velocities during visual stimulation can be assessed by transcranial Doppler sonography (TCD). METHODS: We investigated the possible relationship between the characteristics of photic driving in the EEG elicited by repetitive intermittent photic stimulation and the photoreactive flow changes in the posterior and middle cerebral artery (PCA, MCA) of 25 normal controls and 25 patients with focal epilepsy. Cerebral blood flow velocities (CBFV) of the right PCA (P2 segment) and the left middle cerebral artery (MCA) were measured using a 2 Hz transcranial Doppler device. Simultaneously, scalp EEGs were recorded. RESULTS: During photic stimulation the mean CBFV increase was 20.4 +/- 9.5% in the PCA of the controls (n = 132 stimulations) and 16.0 +/- 10.8% in epileptic patients (n = 150 stimulations, P < 0.01). During those stimulation series with a good EEG driving response (n = 203), the mean increase of CBFV in the PCA was 19.7 +/- 10.0%, as opposed to 14.4 +/- 10.5% during the stimulations with a poor EEG response (n = 79, P < 0.01). A good photic driving response was associated with a higher increase of CBFV in the PCA than a poor one. The increase in CBFV of the PCA in normal controls was higher than in patients with focal epilepsy. CONCLUSIONS: This may indicate that epileptic patients have a reduced coupling between neuronal activation and blood flow.

Adolescent↗
PubMed1998

Cerebral hemodynamic response to generalized spike-wave discharges.

PURPOSE: Data in the literature concerning metabolic demand during generalized spike-wave activity (gSW) are conflicting. We investigated instantaneous changes in cerebral blood flow velocities (CBFV) in both middle cerebral arteries (MCAs) by transcranial Doppler sonography (TCD) during gSW paroxysms recorded by scalp EEG. METHODS: In 13 patients, CBFVs in both MCAs were averaged, time-locked to the occurrence of the gSW; respiratory rate (RR) and end-expiratory pco2 were measured in one patient. RESULTS: Nine patients showed significant changes in CBFV during gSW. Four had biphasic flow changes with an initial increase (p < 0.05) and a subsequent decrease (p < 0.01). This was partially paralleled by an increase in RR (p < 0.01) and a decrease in pco2 (p < 0.01). In three patients, an increase in CBFV that preceded the onset of gSW by several seconds was observed, followed by a decrease in CBFV. Two patients showed a significant decrease only of CBFV. Only gSWs of a median duration of >0.8 s were associated with significant changes in CBFV. CONCLUSIONS: We were able to demonstrate that gSWs of several seconds duration lead to cortical perfusion changes. We suggest that the initial increase of CBFV demonstrated in some patients reflects neuronal activation, whereas the subsequent decrease might in part be due to hyperventilation-induced hypocapnia.

Adult↗
PubMed1998

Measurement of temporal asymmetries of glucose consumption using linear profiles: reproducibility and comparison with visual analysis.

AIM: One approach to regionally analyze temporal glucose consumption consists in drawing linear profiles over the maximal values measured in the temporal cortical ribbon. The aim of our study was to test the reproducibility of this method and to compare its diagnostic performance to that of visual analysis in patients with complex partial seizures (CPS). METHODS: Regional cerebral glucose consumption (rCMRGIc) was measured interictally in 25 CPS patients and 10 controls using F-18-deoxyglucose and the positron emission tomography (PET) camera ECAT EXACT 47. The PET scans were visually analyzed for the occurrence of unilateral temporal hypometabolism. Furthermore, rCMRGIc was quantified on six contiguous coronal planes by manually tracing maximal values of temporal glucose consumption, thus creating line profiles of temporal glucose consumption for each side. Indices of asymmetry (ASY) were then calculated from these line profiles in four temporal regions and compared to the corresponding 95% confidence intervals of the control data. All analyses were performed by two observers independently from each other and without knowledge of the clinical findings. RESULTS: The agreement between the two observers with regard to focus lateralization was 96% (kappa = 0.93) on visual analysis and 100% (kappa = 1) on quantitative analysis. There was an excellent agreement with regard to focus lateralization between visual and quantitative evaluation (kappa = 0.8). CONCLUSION: Quantitation of local temporal rCMRGIc by using linear profile analysis is highly reproducible; for the lateralization of epileptogenic foci, however, this method does not possess significant advantages over the visual evaluation of the scans.

Adult↗
PubMed1998

PET and SPECT in medically non-refractory complex partial seizures. Temporal asymmetries of glucose consumption, benzodiazepine receptor density, and blood flow.

AIM: In contrast to medically refractory complex partial seizures (CPS), only limited knowledge exists on cerebral perfusion and metabolism in medically non-refractory CPS. The aim of this study was to investigate the frequency of temporal asymmetries in regional cerebral glucose consumption (rCMRGlc), regional cerebral blood flow (rCBF), and regional cerebral benzodiazepine receptor density (BRD) in this group of patients. METHODS: The study included 49 patients with medically non-refractory cryptogenic CPS (age: 36.0 +/- 16.1 years). rCMRGlc was studied with F-18-FDG-PET (FDG), rCBF with Tc-99m-ECD-SPECT (ECD), and BRD with l-123-iomazenil-SPECT (IMZ). All studies were performed interictally and within four weeks in each patient. Duration of epilepsy ranged from 0.1 to 42 years (median 4.0 years). SPECT was performed with the triple-headed SPECT camera Multispect 3, PET with the PET camera ECAT EXACT 47. Using linear profiles, glucose consumption, as well as uptake of ECD and IMZ, were measured in four temporal regions of interest (ROIs), and asymmetry indices were calculated (ASY). The results were compared to 95% confidence intervals determined in control subjects. RESULTS: Thirty-five of the 49 (71%) patients had at least one significantly elevated ASY; temporal rCMRGlc was asymmetrical in 41% of the patients, temporal BRD in 29%, and temporal rCBF in 24%. One patient had an asymmetry of all three variables, two of temporal rCMRGlc and BRD, three of temporal rCMRGlc and rCBF, and another four of rCBF and BRD. Fourteen patients had an isolated temporal asymmetry in rCMRGlc, seven in BRD, and four in rCBF. A discrepancy in lateralization between the three modalities was not observed. CONCLUSION: The majority of patients with medically non-refractory CPS have focal abnormalities of blood flow and metabolism in their temporal lobe. In this group of patients, FDG-PET demonstrates abnormalities with the highest frequency of the three modalities studied, followed by IMZ-SPECT, and ECD-SPECT.

Adolescent↗
PubMed1997

Concentrations of lamotrigine in a mother on lamotrigine treatment and her newborn child.

OBJECTIVE: To investigate the transfer of lamotrigine in pregnancy and during lactation from a mother on lamotrigine treatment to her child. METHODS: Concentrations of lamotrigine were measured by high-pressure liquid chromatography in umbilical cord serum and in serum samples of the mother and her child as well as in the mother's milk during the first five postpartum months. RESULTS: In the child lamotrigine serum concentrations (up to 2.8 micrograms ml-1) comparable to those usually achieved in active treatment with lamotrigine were found not only after birth, but also during lactation. A considerable amount of lamotrigine (2-5 mg per day) was excreted in breast milk. No adverse effects were seen in the child. CONCLUSION: The transfer of lamotrigine taking place during pregnancy and lactation should not be neglected. In this case the child should be thoroughly observed for potential adverse effects.

Adult↗
PubMed1997

Spontaneous oscillations in cerebral blood flow velocities in middle cerebral arteries in control subjects and patients with epilepsy.

BACKGROUND AND PURPOSE: Cardiac arrhythmias mediated by the sympathetic nervous system have been implicated in sudden, unexplained deaths in patients with epilepsy. Cerebral blood flow velocities (CBFV) as measured by transcranial Doppler are characterized by slow spontaneous oscillations in part attributed to changes in sympathetic activity (M waves, 3 to 9 cycles per minute) and to discharges of monoaminergic neurons in the brain stem (B waves, 0.5 to 2 cycles per minute). This study was designed to compare spontaneous fluctuations of CBFV in patients with epilepsy with those in normal control subjects. METHODS: Simultaneous registrations of scalp electroencephalograms, with electrodes placed according to the 10-20 System, and transcranial Doppler recordings of both middle cerebral arteries were performed in 27 patients (9 with primary generalized epilepsy, 18 with focal epilepsy). Data analysis of CBFV was based on the envelope curves of the Doppler spectrum. A fast Fourier transformation over the 20-minute CBFV curve was performed, and the amplitudes of B and M waves were calculated and compared with those in 20 normal, age-matched control subjects. RESULTS: While the amplitudes of the B waves in both groups were similar, patients with epilepsy showed significantly increased M waves. Patients with focal epilepsy did not present asymmetries between the normal hemisphere and the side of the epileptic focus with respect to both M and B waves. CONCLUSIONS: Enhanced M waves in epileptic patients may reflect increased sympathetic activity even in the absence of seizures. This study provides further evidence for an autonomic dysfunction as a possible mechanism for sudden unexplained death in patients with epilepsy.

Adult↗
PubMed1996

Reduced GABAA receptor density contralateral to a potentially epileptogenic MRI abnormality in a patient with complex partial seizures.

Imaging cerebral GABAA receptor density (GRD) with single-photon emission tomography (SPET) and iodine-123 iomazenil is highly accurate in lateralizing epileptogenic foci in patients with complex partial seizures of temporal origin. Limited knowledge exists on how iomazenil SPET compares with magnetic resonance imaging (MRI) in this regard. We present a patient with complex partial seizures in whom MRI had identified an arachnoid cyst anterior to the tip of the left temporal lobe. Contralaterally to this structural abnormality, interictal electroencephalography (EEG) performed after sleep deprivation disclosed an intermittent frontotemporal dysrhythmic focus with slow and sharp waves. On iomazenil SPET images GRD was significantly reduced in the right temporal lobe and thus contralaterally to the MRI abnormality, but ipsilaterally to the pathological EEG findings. These data suggest that iomazenil SPET may significantly contribute to the presurgical evaluation of epileptic patients even when MRI identifies potentially epileptogenic structural lesions.

Adult↗
PubMed1995

Scalp topography and analysis of intracranial sources of face-evoked potentials.

Several reports have described that a positive vertex peak of an evoked potential varied in amplitude and latency specifically when images of faces were the eliciting stimulus. The scalp topography and the possible underlying dipole sources of this peak are the subject of this report. We presented black-and-white photographs of human faces, flowers and leaves to 16 healthy subjects and recorded the evoked brain potentials from 31 scalp electrodes. We found the previously described higher amplitude of the positive vertex peak when faces were the crucial stimulus, but the latency of this peak was the same (180 ms) for all three categories of stimulus. At the posterior temporal electrodes, the face waveforms showed a negative peak at 175 ms, which was only rudimentary in the waveforms elicited by the other stimuli. Since in most previous reports a mastoid reference was used, it is most likely that the previously described latency shift of the positive vertex peak associated with face stimuli was due to the interaction with this posterior temporal peak. The dipole analysis of the possible generators of the recorded potentials suggested the sequential activation of occipital, lateral temporal and mesio-temporal brain structures during the perception of a human face.

Adult↗
PubMed1994

[Cardiac side effects and ECG changes with lamotrigine?--A clinical study].

After a patient treated with lamotrigine (LTG) had suffered from thoracal pain and repolarisation deficiencies in the electrocardiogram (ECG), we prospectively investigated 20 patients with localization-related epilepsies to assess cardiovascular side effects of LTG. During the study, LTG was added to a stable dosage of one to three first line antiepileptic drugs (AED). Physical examinations and ECG recordings were performed regularly. Clinical cardial side effects did not occur. Only in single ECG traces of six patients non specific abnormalities were seen. Only in one patient, the abnormalities (supraventricular extrasystoles and a first grade atrioventricular block) unequivocally appeared initially under LTG. However, in the same patient two later ECG recordings under higher LTG dosages were normal. The statistical analysis of the ventricular activation times did not reveal any significant changes under LTG (p = 0.05) with the exception of an extended PQ time when comparing a patient group before LTG (n = 11) with another patient group under LTG (n = 11). Since this observation was not confirmed by the statistical analysis of a third patient group (n = 10) with ECG data prior to and under LTG, we believe that the statistically significant changes mentioned above were based mainly on structural differences between the patient groups and not on true LTG effects. Our results do not give evidence for an elevated risk of clinically relevant cardial side effects under LTG.

Adolescent↗
PubMed1993

Temporary abolition of seizure activity by flumazenil in a case of valproate-induced non-convulsive status epilepticus.

We report on a 33-year-old female suffering from frequent complex-partial seizures who developed a non-convulsive status epilepticus after one week of antiepileptic therapy with valproate (VPA) which had been added to a basic medication with barbexaclone (BBC) in rapidly increasing dosage. The electroencephalogram (EEG) showed continuous rhythmic generalized sharp and slow wave activity with a frontal maximum. Intravenous administration of 3.0 mg of the benzodiazepine (BZ) receptor antagonist flumazenil under monitoring with video-EEG led to an immediate and marked electroclinical improvement, whereas 6.0 mg of the BZ receptor agonist midazolam was followed by a deterioration both clinically and in the EEG. We discuss the concept of VPA-encephalopathy and the possible mechanisms of the action of flumazenil on VPA-induced as well as on other toxic and metabolic encephalopathies. Flumazenil might antagonize increased benzodiazepine receptor activity with agonistic and even convulsive properties in these encephalopathic syndromes. Further investigations are needed concerning the relation of drug-induced or metabolic encephalopathies and central benzodiazepine receptor activity. We recommend a therapeutic trial with flumazenil, if stupor or decreased seizure control develop in patients treated with valproate.

Adult↗
PubMed1993

Transcranial magnetic stimulation (TMS) of the brain in patients with mesiotemporal epileptic foci.

Transcranial magnetic stimulation (TMS) of the human brain is mainly used for the diagnosis of diseases with disturbed central motor conduction. Recent studies revealed controversial results concerning the possibility of a TMS-induced specific activation of epileptogenic foci in patients with localization-related epilepsies, which would make TMS an additional diagnostic tool for the presurgical localization of the primary epileptogenic zone. We applied TMS to 19 patients with complex-partial seizures and investigated its effects and safety. In 12 patients we performed TMS during scalp electroencephalogram (EEG) recordings. The remaining 7 patients with localization-related epilepsies of mesiobasal limbic seizure origin underwent EEG with additionally implanted foramen-ovale-electrodes (FOE). We did not notice any significant spike activation and even observed bilateral reduction of epileptic activity in some patients. On the contrary, hyperventilation induced a marked activation of the epileptic focus. Our findings support that TMS is safe since adverse effects did not occur. However, due to possible safety hazards, TMS in epileptic patients still requires cautious application until more data will be available.

Anticonvulsants↗
PubMed1992

Hyponatremic coma under oxcarbazepine therapy.

Oxcarbazepine (OXC) is considered to be a promising new antiepileptic drug with similar efficacy and better tolerability compared to carbamazepine (CBZ). However, hyponatremia is supposed to occur even more often than with CBZ. We report on a patient who developed hyponatremic coma under OXC with a serum sodium level of 115 mmol/l, the second published case of OXC-induced hyponatremia with serious clinical adverse effects.

Anticonvulsants↗
PubMed1991

Abolition of photoparoxysmal response in progressive myoclonus epilepsy.

We have investigated the effect of piracetam on photoparoxysmal responses in 3 patients with progressive myoclonus epilepsy. With doses of up to 10 g/day, elimination of photoparoxysmal responses was achieved in all 3 patients. Corresponding to EEG improvement, the clinical performance improved slightly in 2 patients and definitely in 1 patient when piracetam was added to their medication of valproate and clonazepam. According to our data, medical treatment of myoclonus with piracetam is justified particularly in myoclonus of cortical origin.

Adolescent↗
PubMed1985

The 'foramen ovale electrode': a new recording method for the preoperative evaluation of patients suffering from mesio-basal temporal lobe epilepsy.

A technique to record from the mesio-basal aspect of the temporal lobe by a subdural electrode inserted through the foramen ovale (FO) is described. For this purpose a special electrode was developed that, in addition, allowed epicortical DC recording. After having tested its value experimentally in dogs with penicillin-induced hippocampal seizure foci, this 'FO electrode' was subsequently applied to 10 patients. Nine of them suffered from drug-resistant complex partial seizures suspected to be of mesio-basal limbic origin. Seven patients had in addition to the FO electrode depth electrodes stereotactically implanted within the hippocampus and nucleus amygdalae, thus allowing an evaluation of this new FO recording technique by direct comparison with stereo-EEG. Our results indicate that interictal epileptiform potentials as well as ictal discharges are reliably picked up by the FO electrode whenever nucleus amygdalae, hippocampus and parahippocampal gyrus show synchronous epileptic activity. As a rule, these events are not reflected in conventional scalp EEG records. Epileptiform activity in subcompartments of the mesio-basal limbic structures is not reliably reflected by the FO electrode. Negative epicortical DC shifts recorded by the FO electrode are a sensitive indicator of epileptic activity within the underlying deeper structures. In conclusion, in certain patients with drug-resistant epilepsy of suspected mesio-basal limbic origin the use of FO recording in the presurgical evaluation might provide sufficient information to give an indication for resective surgery, either by anterior temporal lobectomy or by selective amygdalo-hippocampectomy.

Amygdala↗
PubMed1985

Foramen ovale electrodes: a new technique enabling presurgical evaluation of patients with mesiobasal temporal lobe seizures.

A recently developed technique to record from the mesiobasal aspect of the temporal lobes by subdural electrodes inserted through the foramen ovale is described. Experience with this technique in 13 candidates for surgical epilepsy therapy is presented. Our results indicate that interictal epileptiform potentials as well as ictal discharges are reliably picked up by the foramen ovale electrode whenever nucleus amygdallae, hippocampus and parahippocampal gyrus show synchronous epileptic activity. The advantages of this technique are discussed.

Adolescent↗