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Biomedical subjects

A Ebner

Publications and source records attributed to A Ebner.

At least 19 recordsLinked to original sources
PubMed2006

Patients' ability to react before complex partial seizures.

OBJECTIVE: The purpose of the study described here was to investigate the pathophysiology of patients' ability to react during the conscious (aura) phase of complex partial seizures (CPS) originating from the temporal lobe. METHODS: We reviewed video recordings of CPS experienced by 130 adult patients who had undergone epilepsy surgery for intractable medial temporal lobe epilepsy. All patients were instructed to push the alarm button when they felt an aura. We defined the preictal reactivity as the ability to push the alarm button before the complex partial (unconscious) phase of seizures. RESULTS: Seventy-seven patients (59%) pushed the alarm button before seizures. Patients with preictal reactivity were significantly younger, more often had lateralized EEG seizure patterns, and had a better postoperative outcome. Patients who did not push the alarm button had secondarily generalized seizures more often. CONCLUSIONS: Ability to react before CPS is associated with a circumscribed region involved at seizure onset and spread, and with a seizure-free postoperative outcome.

Adolescent↗
PubMed2006

Unilateral hand automatisms in temporal lobe epilepsy.

OBJECTIVES: To analyse the lateralising value of unilateral manual automatism (UMA), its relation to contralateral dystonia and the hand by which the UMA was performed. METHODS: In this retrospective study, we reviewed video recordings of 141 patients (mean age 34.1+/-10) who had consecutively undergone presurgical evaluations with ictal video-EEG recordings and high-resolution MRI, had had epilepsy surgery due to intractable medial temporal lobe epilepsy with complex partial seizures due to unilateral medial temporal lobe lesions. The video recordings were prospectively reviewed by one of the authors blinded to patient's clinical data except the diagnosis of medial temporal lobe epilepsy. Altogether 310 archived seizures were analysed. RESULTS: Hand automatisms occurred in 86.5% of patients. UMA occurred in 53% of patients. If UMA was accompanied by contralateral hand dystonia, it had a high lateralising value to the ipsilateral epileptic focus (EF), it was ipsilateral in 85% of patients. Conversely, if UMA occurred without contralateral dystonia, it had only a limited lateralising value because it was ipsilateral to the EF in only 63% of patients. However, we found that left-sided UMA without dystonia had a high lateralising value to the left hemisphere (ipsilateral to the EF in 82%), while right-sided UMA without dystonia has practically no lateralising value. CONCLUSIONS: UMA with contralateral dystonia has a high lateralising value to the ipsilateral hemisphere. Left-sided UMA without contralateral dystonia has a lateralising value to the left hemisphere. Right-sided UMA without contralateral dystonia has no lateralising value.

Adolescent↗
PubMed2006

Laughter and the mesial and lateral premotor cortex.

We report the induction of laughter and smiling by cortical electrical stimulation of the frontal lobe of two patients: an 18-month-old boy with a left frontal cortical lesion extending to the vertex and the central gyrus, and a 35-year-old woman with a lesion in the right supplementary sensorimotor area (SSMA). The subjects underwent presurgical epilepsy evaluation with subdural grid electrodes to determine surgical candidacy. Stimulation of the prefrontal area reproducibly induced laughter. The adult patient reported absence of emotional content. Slowing of speech occurred under stimulation of electrodes in the upper and posterior vicinity. In this patient laughter was elicited in the anterior part of the SSMA. In the child, this response was induced by stimulation of the lateral prefrontal cortex near the midline. We conclude that the anterior portion of the SSMA/lateral premotor cortex is involved in generating the motor pattern of laughter.

Adult↗
PubMed2006

Improving the contrast of topographical AFM images by a simple averaging filter.

New image-processing methods were applied to atomic force microscopy images in order to visualize small details on the surface of virus particles and living cells. Polynomial line flattening and plane fitting of topographical images were performed as first step of the image processing. In a second step, a sliding window approach was used for low-pass filtering and data smoothing. The size of the filtering window was adjusted to the size of the small details of interest. Subtraction of the smoothed data from the original data resulted in images with enhanced contrast. Topographical features which are usually not visible can be easily discerned in the processed images. The method developed in this study rendered possible the detection of small patterns on viral particles as well as thin cytoskeleton fibers of living cells. It is shown that the sliding window approach gives better results than Fourier-filtering. Our method can be generally applied to increase the contrast of topographical images, especially when small features are to be highlighted on relatively high objects.

Animals↗
PubMed2006

[Correlation between sex, intrauterine position and familial predisposition and neonatal hip ultrasound results].

AIM: To correlate findings of hip ultrasound on day 4-10 of life with sex, intrauterine position and a positive family history for congenital hip anomalies. METHODS: The SNiP-study ( Survey of Neonates In Pommerania) registered 2256 neonates (2030 term, 226 preterm) between May 2002 and March 2004. Hip ultrasound results of 1043 term and since October 2003 33 preterm neonates were analysed. Time of ultrasound was day 4-10 after birth. Preterm neonates were examined when reaching their corrected term gestational age. Ultrasound was applied with a 7.5 MHz linear scanner and results were classified according to Graf. Chi-square and Fishers exact test were used for statistical analysis. RESULTS: 4.9 % of the screened hips were classified as IIc or higher, 3.1 % were unilateral and 1.7 % bilateral. Incidence was significantly higher (p < 0.023) in females (6.6 %) than in males (3.2 %). There was no significant difference in intrauterine position or positive family history for hip anomalies with 3.7 % for mothers, 1.2 % of fathers and 2.4 % of siblings positive. There was a higher incidence for congenital hip dysplasia in preterms with 6.1 %, which is not significant due to the limited number. DISCUSSION: Current screening methods miss up to 18 % of newborns with severe hip dysplasia. We were able to demonstrate that screening for congenital hip dysplasia with ultrasound is a diagnostic tool even during the first days of life. There is a significantly higher incidence of congenital hip dysplasia in females, but in contrast to other studies we found no significant difference in intrauterine position or familial history. Earlier diagnosis and therapy on the base of relevant risk factors might correspond with an improved prognosis and outcome. Further studies are warranted to evaluate the significance in preterm neonates.

Female↗
PubMed2006

Prognostic factors for surgery of neocortical temporal lobe epilepsy.

OBJECTIVES: In the current classification of epilepsies two forms of temporal lobe epilepsy (TLE) were included: mesial and lateral (neocortical) TLE. We aimed at identifying prognostic factors for the surgical outcome of lesional neocortical TLE. METHODS: We included consecutive patients who had undergone presurgical evaluation including ictal video-EEG and high-resolution MRI, who had TLE due to neocortical lateral epileptogenic lesions, who had a lesionectomy and who had >2-year follow-up. RESULTS: There were 29 patients who met the inclusion criteria. Twenty of them became postoperatively seizure-free. Patients' mean age was 34.8+/-9 years (range 18-52). The age at epilepsy onset was 20.1+/-8 years. We found that left-sided surgery (p=0.048) and focal cortical dysplasia (FCD) on MRI (p=0.005) were associated with non-seizure-free outcome, while lateralized/localized EEG seizure pattern (p=0.032), tumors on the MRI (p=0.013), and a favorable seizure situation at the 6-month postoperative evaluation were associated with 2-year postoperative seizure-freedom (p<0.001). Multivariate analysis indicated that the side of surgery was not an independent predictor. CONCLUSION: More than two-thirds of the patients with neocortical TLE became seizure-free postoperatively. Lateralized/localized EEG seizure pattern and tumors on the MRI were associated with postoperative seizure-freedom, while FCD were associated with a poor outcome. The 6-month postoperative outcome is a reliable predictor for the long-term outcome.

Adolescent↗
PubMed2006

[Suggestion for a new, patient-oriented epilepsy classification].

The recent proposal by the ILAE Task Force for Epilepsy Classification is a multiaxial, syndrome-oriented approach. Epilepsy syndromes--at least as defined by the ILAE Task Force--group patients according to multiple, usually poorly defined parameters. As a result, these syndromes frequently show significant overlap and may change with patient age. We propose a five-dimensional and patient-oriented approach to epilepsy classification. This approach shifts away from syndrome orientation, using independent criteria in each of the five dimensions similarly to the diagnostic process in general neurology. The main dimensions of this new classification consist of (1) localizing the epileptogenic zone, (2) semiology of the seizure, (3) etiology, (4) seizure frequency, and (5) related medical conditions. These dimensions characterize all information necessary for patient management, are independent parameters, and include information more pertinent than the ILAE axes with regard to patient management. All cases can be classified according to this five-dimensional system, even at initial encounter when no detailed test results are available. Information from clinical tests such as MRI and EEG are translated into the best possible working hypothesis at the time of classification, allowing increased precision of the classification as additional information becomes available.

Epilepsy↗
PubMed2005

Transient lesion in the splenium of the corpus callosum and antiepileptic drug withdrawal.

OBJECTIVE: To test pathophysiologic hypotheses regarding the occurrence of a splenial lesion in patients with epilepsy. METHODS: The authors studied 16 patients with a splenial lesion and 32 control patients, all of whom had MRI examination immediately after presurgical EEG long-term monitoring (LTM). The authors compared the number of generalized tonic-clonic and partial seizures during LTM, antiepileptic drug (AED) withdrawal, and laboratory results. RESULTS: All of the patients with a splenial lesion had their AEDs stopped completely, vs 47% of the controls (p = 0.001). Patients with SCC lesion had a longer duration of complete withdrawal (median 3.5 vs 2 days, p = 0.03). There was no correlation with seizure frequency or the introduction of new AEDs. CONCLUSION: A lesion of the splenium of the corpus callosum in patients with epilepsy is not associated with toxic drug effects or high seizure frequency, but might be induced by a rapid and relatively long-lasting reduction of antiepileptic drugs. Its frequency might be underestimated as MRI after long-term monitoring is rarely done.

Adolescent↗
PubMed2005

Temporal lobe epilepsy with hippocampal sclerosis: predictors for long-term surgical outcome.

Temporal lobe epilepsy (TLE) accompanied by hippocampal sclerosis (HS) is the type of epilepsy most frequently operated on. The predictors for long-term seizure freedom after surgery of TLE-HS are unknown. In this study, we aimed to identify prognostic factors which predict the outcome 6 months and 2, 3 and 5 years after epilepsy surgery of TLE-HS. Our working hypothesis was that the prognostic value of potential predictors depended on the post-operative time interval for which the assessment was made. We included 171 patients (100 females and 71 males, aged 16-59 years) who had undergone presurgical evaluation, including video-EEG, who had had MRI-defined HS, and who had undergone temporal lobectomy. We found that secondarily generalized seizures (SGTCS) and ictal dystonia were associated with a worse 2-year outcome. Both these variables together with older age and longer epilepsy duration were also related to a worse 3-year outcome. Ictal limb dystonia, older age and longer epilepsy duration were associated with long-term surgical failure evaluated 5 years post-operatively. In order to determine the independent predictors of outcomes, we calculated multivariate analyses. The presence of SGTCS and ictal dystonia independently predicted the 2-year outcome. Longer epilepsy duration and ictal dystonia predicted the 3-year outcome. Longer epilepsy duration (P = 0.003) predicted a poor 5-year outcome. Conclusively, predictors for the long-term surgical results of TLE with HS are different from those variables that predict the short-term outcome. Epilepsy duration is the most important predictor for long-term surgical outcome. Our results strongly suggest that surgery for TLE-HS should be performed as early as possible.

Adolescent↗
PubMed2005

Vagus nerve stimulation: predictors of seizure freedom.

OBJECTIVES: To identify predictive factors for the seizure-free outcome of vagus nerve stimulation (VNS). METHODS: All 47 patients who had undergone VNS implantation at one centre and had at least one year of follow up were studied. They underwent complete presurgical evaluation including detailed clinical history, magnetic resonance imaging, and long term video-EEG with ictal and interictal recordings. After implantation, adjustment of stimulation parameters and concomitant antiepileptic drugs were at the discretion of the treating physician. RESULTS: Mean (SD) age of the patients was 22.7 (11.6) years (range 7 to 53). Six patients (13%) became seizure-free after the VNS implantation. Only two variables showed a significant association with the seizure-free outcome: absence of bilateral interictal epileptiform discharges (IED) and presence of malformation of cortical development (MCD). Epilepsy duration showed a non-significant trend towards a negative association with outcome. By logistic regression analysis, only absence of bilateral IED correlated independently with successful VNS treatment (p<0.01, odds ratio = 29.2 (95% confidence interval, 2.4 to 353)). Bilateral IED (independent or bilateral synchronous) was found in one of six seizure-free patients and in 33 of 41 non-seizure-free patients. When bilateral IED were absent, the sensitivity for seizure-free outcome was 0.83 (0.44 to 0.97), and the specificity was 0.80 (0.66 to 0.90). CONCLUSIONS: Bilateral IED was independently associated with the outcome of VNS. These results are preliminary because they were based on a small patient population. They may facilitate prospective VNS studies enrolling larger numbers of patients to confirm the results.

Adolescent↗
PubMed2005

Spike frequency is dependent on epilepsy duration and seizure frequency in temporal lobe epilepsy.

OBJECTIVES: We wanted to investigate factors that are associated with frequency of interictal epileptiform discharges by investigating 303 patients with temporal lobe epilepsy (TLE). METHODS: We included all patients who consecutively underwent the adult presurgical evaluation program at our center and who had intractable, medial TLE with complex partial seizures due to unilateral medial temporal lobe lesions. The interictal EEG samples were automatically recorded and stored on computer. The location and frequency of interictal epileptiform discharges were assessed by visual analysis of interictal EEG samples of 2-minute duration every hour. RESULTS: There were 303 patients (aged 16-63) who met the inclusion criteria. The median interictal epileptiform discharge frequency was 15 IED/h, the median seizure frequency was 4 seizures/month. According to univariate analyses, we found that age at monitoring, epilepsy duration, and higher seizure frequency were associated with higher interictal epileptiform discharge frequency. In the logistic regression analysis, we found that higher seizure frequency (p < 0.001) and longer epilepsy duration (p = 0.007) were independently associated with higher spike frequency, while the age at monitoring was not. CONCLUSIONS: Seizure frequency and epilepsy duration (years of patient's life with seizure activity) were independently associated with IED frequency, suggesting that IED are modulated by seizures.

Adolescent↗
PubMed2004

Epileptic activity influences the lateralization of mesiotemporal fMRI activity.

OBJECTIVE: To identify clinical factors contributing to the lateralization of mesiotemporal memory functions in epilepsy by using memory-activated fMRI. METHODS: Sixty patients aged 16 to 63 years with mesial temporal lobe epilepsy (MTLE) and 20 patients aged 16 to 60 years with extratemporal epilepsy (ETE) due to circumscribed epileptogenic lesions who consecutively underwent presurgical evaluation including continuous video-EEG monitoring and structural MRI examinations were examined. During memory fMRI, the activation condition consisted of retrieval from long-term memory induced by self-paced performance of an imaginative walk through the patient's hometown. On the basis of a previous study, memory lateralization was defined as typical if larger fMRI activation was in the mesiotemporal structures contralateral to the epileptic focus. RESULTS: There were 45 patients with MTLE who had typical memory lateralization (75%), whereas only 9 patients (45%) with ETE exhibited typical memory lateralization (p = 0.013). In MTLE patients, bilateral independent epileptiform discharges occurred more often in the atypical group than in patients with typical memory lateralization (p = 0.015). CONCLUSIONS: The fMRI lateralization of mesiotemporal visuospatial memory functions in patients with mesiotemporal lobe epilepsy (MTLE) is asymmetric: The larger activation usually appears contralateral to the side of the epileptogenic region. These findings occur more often in MTLE; in patients with extratemporal epilepsy, such type of asymmetry is not characteristic. In MTLE patients with bilateral independent epileptiform discharges, this type of asymmetry is also less frequent.

Adolescent↗
PubMed2004

Characterization of a fast transient outward current in neocortical neurons from epilepsy patients.

A-type currents powerfully modulate discharge behavior and have been described in a large number of different species and cell types. However, data on A-type currents in human brain tissue are scarce. Here we have examined the properties of a fast transient outward current in acutely dissociated human neocortical neurons from the temporal lobe of epilepsy patients by using the whole-cell voltage-clamp technique. The A-type current was isolated with a subtraction protocol. In addition, delayed potassium currents were reduced pharmacologically with 10 mM tetraethylammonium chloride. The current displayed an activation threshold of about -70 mV. The voltage-dependent activation was fitted with a Boltzmann function, with a half-maximal conductance at -14.8 +/- 1.8 mV (n = 5) and a slope factor of 17.0 +/- 0.5 mV (n = 5). The voltage of half-maximal steady-state inactivation was -98.9 +/- 8.3 mV (n = 5), with a slope factor of -6.6 +/- 1.9 mV (n = 5). Recovery from inactivation could be fitted monoexponentially with a time constant of 18.2 +/- 7.5 msec (n = 5). At a command potential of +30 mV, application of 5 mM 4-aminopyridine or 100 microM flecainide resulted in a reduction of A-type current amplitude by 35% or 22%, respectively. In addition, flecainide markedly accelerated inactivation. Current amplitude was reduced by 31% with application of 500 microM cadmium. All drug effects were reversible. In conclusion, neocortical neurons from epilepsy patients express an A-type current with properties similar to those described for animal tissues.

Adolescent↗
PubMed2004

Orgasmic aura--a report of seven cases.

We report on seven patients who experienced an orgasmic aura at the start of their seizures. The patients (five women, two men) were aged 36-58. Three of seven patients described the exact nature of their auras only many years after their appearance, when the epilepsy diagnostic procedure became more intensive due to drug resistance. Moreover, one patient even refused any new therapeutical options due to the reportedly positive role of the orgasmic aura in her life. All of our patients had temporal lobe epilepsy. The clinical picture, EEG, MRI or SPECT findings suggested a right temporal epileptic focus in six patients, while in one patient the epileptogenic region was localised in the left temporal lobe. In the latter case, the left hemisphere was speech-dominant, while in the other cases no Wada tests were done. Our results confirm that orgasmic aura could be considered as an ictal lateralising sign to the right hemisphere, however, it has no 100% lateralising value.

Adult↗
PubMed2004

Intentional seizure interruption may decrease the seizure frequency in drug-resistant temporal lobe epilepsy.

We investigated the nature of preictal subjective phenomena and whether they had any effect on the seizure frequency in 95 adult patients with medial temporal lobe epilepsy. Seventy-three (77%) patients indicated that they experienced seizure-provoking factors. Ten patients (11%) had prodromas independent of auras, while auras occurred in 89%. Forty-four patients (46%) reported that that they had tried to stop their seizures in the presence of prodroma or aura and this action had resulted in success at least once. Twenty-one patients (22%) regularly tried to stop their seizures because this effort was often successful according to their interpretation. Patients who reported that they could frequently inhibit their seizures had 1.8 +/- 1.6 seizures/month, a significantly lower mean seizure frequency than those 74 patients who did not do it regularly (4.6 +/- 4.8 seizures/month, P<0.001). Patients who reported regular experience in inhibiting intentionally their seizures more often had affective (P=0.05) and vertiginous auras (P<0.01) as well as isolated auras (P<0.05). Patients who experienced provoking factors showed the same seizure frequency as those who did not. Our results suggest that intentional seizure inhibition had an impact on the severity of drug-resistant epilepsy.

Adolescent↗
PubMed2004

Simple partial seizures (isolated auras) in medial temporal lobe epilepsy.

We analysed whether the medial temporal lobe epilepsy (MTLE) with isolated auras makes any difference in the clinical picture in comparison with MTLE in which only complex partial seizures (CPS) occur. We included 100 patients (aged 16-59 years) with unilateral medial temporal lobe lesions who consecutively underwent presurgical evaluation due to intractable MTLE and who became completely aura- and seizure-free after the anterior temporal resection. Preoperatively, isolated auras were present in 70 patients. These patients were categorised into the IA group. The remaining 30 patients in whom the auras preceded seizures were categorised into the NIA group. We found no difference between the two groups for the age at onset, epilepsy duration or aura types. Conversely, a right-sided epileptogenic region (61%) occurred more frequently in the IA group than in the NIA group (27%, P = 0.001). Conclusively, isolated auras show affinity to the right hemisphere. One explanation may be that seizures stop more quickly in the right hemisphere. Another hypothesis is that consciousness can be disturbed much easier by the ictal activity in left temporal seizures: auras evolve more frequently to CPS due to the disturbance of consciousness.

Adolescent↗