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Biomedical subjects

P Halász

Publications and source records attributed to P Halász.

At least 19 recordsLinked to original sources
PubMed2006

Electrode manipulation automatism during temporal lobe seizures.

OBJECTIVE: To describe clinical characteristics and lateralizing value of peri-ictal electrode manipulation automatism (EMA) in patients with temporal lobe epilepsy (TLE) and compare our data with ictal manual automatisms described in the literature. METHODS: Two-hundred and five videotaped seizures of 55 consecutive patients with refractory TLE and postoperatively seizure-free outcome were analyzed and EMA (tugging, scratching or adjusting the electrodes and cables) were monitored. RESULTS: Twenty-eight (51%) patients showed EMA during 47 (23%) seizures. Ictal start was noted in 22 seizures and in 19/22 cases EMA finished before the end of seizure. Ictal EMAs were always associated with automotor seizure components. During 25 seizures, exclusively postictal EMAs were observed. Electrode manipulation was presented during 24/112 left-sided and 23/93 right-sided seizures (p = 0.742). Peri-ictal EMA was unilateral (completed by one hand) in 24/47 seizures (10 ictal, 14 postictal); it was done by the hand ipsilateral to the seizure onset zone in 17/24 and by contralateral hand in 7/24 cases (p = 0.064). We observed concomitant contralateral dystonic posturing during 3/10 seizures with unilateral ictal EMA. Unilateral hand automatism, temporally independent from the EMA appeared in 30 (64%) of the 47 seizures. CONCLUSION: Peri-ictal EMA is a frequent phenomenon but shows no lateralizing value in TLE. The mechanism of EMA is in many ways dissimilar from that of earlier described manual automatisms.

Adolescent↗
PubMed2006

Lateralizing value of postictal automatisms in temporal lobe epilepsy.

PURPOSE: To describe clinical characteristics and lateralizing value of postictal automatisms in patients with temporal lobe epilepsy (TLE). METHODS: One hundred and ninety-three videotaped seizures of 55 consecutive patients with refractory TLE and postoperatively seizure-free outcome were analyzed. Ictal as well as postictal (manual, oral and speech) automatisms were monitored. RESULTS: Thirty-four (62%) of the 55 patients showed PA at least once during their seizures. Postictal automatism was observed in 70 (36%) attacks as manual (21%), oral (13%) or speech (9%) automatisms. Fifteen seizures contained a combination of two different postictal automatisms. The presence of postictal oral automatisms did not lateralize the seizure onset zone (p=0.834). Speech automatisms (repetitive verbal behavior) occurred more frequently after left-sided seizures (p=0.002). Postictal unilateral manual automatism showed no lateralizing value occurring by the ipsilateral hand in 10 and the contralateral upper limb in 6 seizures (p=0.454). CONCLUSION: : Postictal automatism is a relatively frequent phenomenon in TLE. Postictal speech automatism lateralizes the seizure onset zone to the left hemisphere. Our observation can help the presurgical evaluation of TLE because verbal perseveration frequently occurs spontaneously, even in seizures without appropriate postictal language testing.

Adolescent↗
PubMed2005

Overnight verbal memory retention correlates with the number of sleep spindles.

Despite strong evidence supporting a role for sleep in the consolidation of newly acquired declarative memories, the contribution of specific sleep stages remains controversial. Based on electrophysiological studies in animals, synchronous sleep oscillations have been long proposed as possible origins of sleep-related memory improvement. Nevertheless, no studies to date have directly investigated the impact of sleep oscillations on overnight memory retention in humans. In the present study we provide evidence that overnight verbal memory retention is highly correlated with the number of sleep spindles detected by an automatic algorithm over left frontocentral areas. At the same time, overnight retention of newly learned faces was found to be independent of spindle activity but correlated with non-rapid-eye-movement sleep time. The data strongly support theories suggesting a link between sleep spindle activity and verbal memory consolidation.

Adult↗
PubMed2004

Surviving CA1 pyramidal cells receive intact perisomatic inhibitory input in the human epileptic hippocampus.

Temporal lobe epilepsy (TLE) is known to be linked to an impaired balance of excitation and inhibition. Whether inhibition is decreased or preserved in the human epileptic hippocampus, beside the excess excitation, is still a debated question. In the present study, quantitative light and electron microscopy has been performed to analyse the distribution, morphology and input-output connections of parvalbumin (PV)-immunopositive interneurons, together with the entire perisomatic input of pyramidal cells, in the human control and epileptic CA1 region. Based on the degree of cell loss, the patients with therapy-resistant TLE formed four pathological groups. In the non-sclerotic CA1 region of TLE patients, where large numbers of pyramidal cells are preserved, the number of PV-immunopositive cell bodies decreased, whereas axon terminal staining, and the distribution of their postsynaptic targets was not altered. The synaptic coverage of CA1 pyramidal cell axon initial segments (AISs) remained unchanged in the epileptic tissue. The somatic inhibitory input is also preserved; it has been decreased only in the cases with patchy pyramidal cell loss in the CA1 region (control, 0.637; epileptic with mild cell loss, 0.642; epileptic with patchy cell loss, 0.424 microm synaptic length/100 microm soma perimeter). The strongly sclerotic epileptic CA1 region, where pyramidal cells can hardly be seen, contains a very small number of PV-immunopositive elements. Our results suggest that perisomatic inhibitory input is preserved in the epileptic CA1 region as long as pyramidal cells are present. Basket and axo-axonic cells survive in epilepsy if their original targets are present, although many of them lose their PV content or PV immunoreactivity. An efficient perisomatic inhibition is likely to take part in the generation of abnormal synchrony in the non-sclerotic epileptic CA1 region, and thus participate in the maintenance of epileptic seizures driven, for example, by hyperactive afferent input.

Adolescent↗
PubMed2004

Postoperative interictal spikes during sleep contralateral to the operated side is associated with unfavourable surgical outcome in patients with preoperative bitemporal spikes.

PURPOSE: To correlate the persistence of contralateral spikes during sleep after unilateral surgery with seizure outcome in a temporal lobe epilepsy (TLE) population and to test the existing hypotheses about the origin of the contralateral spikes in temporal lobe epilepsy. METHODS: In the 19 patients selected for this study unilateral temporal lobe surgery was performed. To investigate the course of bilateral interictal epileptiform discharges observed before surgery in awake or sleep over the temporal lobe contralateral to surgery, 24 h mobile 12 channel EEG recording was performed at minimum two, in average 4.6 (2-10) years after the surgery. RESULTS: The association of postoperative contralateral spikes and non-seizure free outcome was highly significant. The existence of unilateral pathology before surgery was highly predictive for good outcome and disappearance of contralateral spikes. The association between good seizure outcome, disappearance of contralateral spikes and the existence of unilateral pathology before surgery was also significant. Our data partially satisfies the expectations of both the "seizure induced" and mirror type secondary epileptogenesis hypotheses concerning origin of contralateral spikes, but were not completely congruent with either of them. CONCLUSIONS: Unfavourable surgical outcome in a temporal lobe epilepsy group with preoperative independent bilateral interictal spikes was associated with the persistence of postoperative contralateral spikes and lack of unilateral pathology. Compared with seizure outcome the presence/absence and distribution of postoperative interictal spikes in NREM sleep not entirely fit to the predictions of existing secondary epileptogenesis hypotheses.

Adolescent↗
PubMed2003

Right hippocampal sclerosis is more common than left after febrile seizures.

Temporal lobe epilepsy (TLE) is frequently associated with hippocampal sclerosis (HS) and a history of febrile convulsions (HFC). The authors investigated 292 patients with TLE due to HS. Left HS occurred more frequently (57%) than right HS (43%, p = 0.01). Forty-seven percent of the patients had HFC. In patients with right HS, HFC occurred in 59.6%, whereas in patients with left HS, HFC was present in 37.5%, showing a highly significant lateralization difference.

Adolescent↗
PubMed2003

Clinical differences in patients with unilateral hippocampal sclerosis and unitemporal or bitemporal epileptiform discharges.

PURPOSE: To investigate factors determining the presence of bilateral interictal epileptiform discharges (IEDs) in temporal lobe epilepsy (TLE) with unilateral hippocampal sclerosis (HS). METHODS: We analysed data of 243 TLE patients with unilateral HS who had long-term video-EEG. Eighty-one patients (33%) had bitemporal IEDs. RESULTS: We categorised patients into a unilateral group (UG), a bilateral group (BG) according to presence of bitemporal IEDs. We found no difference between UG and BG regarding epilepsy duration, secondarily generalised seizures, and history of febrile seizures. Mean seizure frequency was significantly higher in the BG (UG: 7.7+/-14.7 seizures/month; BG: 13+/-35 seizures/month, P=0.01). We found a significant correlation between late epilepsy onset and the presence of bitemporal IEDs. The mean age at epilepsy onset in UG was 10.1+/-7.9 years, while in BG it was 13+/-9.2 years (P=0.02). CONCLUSIONS: The traditional concept of the evolution of mirror focus cannot apply for humans because the duration of epilepsy does not influence the evolution of bitemporal IEDs. Other factors, i.e. age at onset and seizure frequency may play a role in this process. The association between the higher seizure frequency and mirror foci indicates that the development of mirror focus depends on seizures and not on a progressive 'interictal' epileptogenesis.

Adolescent↗
PubMed2003

Misleading hallucinations in unrecognized narcolepsy.

OBJECTIVE: To describe psychosis-like hallucinatory states in unrecognized narcolepsy. METHOD: Two patients with hypnagogic/hypnapompic hallucinations are presented. RESULTS: Both patients had realistic and complex - multi-modal and scenic-daytime sexual hallucinations leading, in the first case, to a legal procedure because of false accusation, and in the second, to serious workplace conflicts. Both patients were convinced of the reality of their hallucinatory experiences but later both were able to recognize their hallucinatory character. Clinical data, a multiple sleep latency test, polysomnography, and HLA typing revealed that both patients suffered from narcolepsy. CONCLUSION: We suggest that in unrecognized narcolepsy with daytime hypnagogic/hypnapompic hallucinations the diagnostic procedure may mistakenly incline towards delusional psychoses. Daytime realistic hypnagogic/hypnapompic hallucinations may also have forensic consequences and mislead legal evaluation. Useful clinical features in differentiating narcolepsy from psychoses are: the presence of other narcoleptic symptoms, features of hallucinations, and response to adequate medication.

Adult↗
PubMed2002

Orgasmic aura originates from the right hemisphere.

The authors present a patient with right mesiotemporal epileptogenic region who experienced orgasmic epileptic aura. Twenty-two similar published cases were also evaluated. Among 15 patients with unilateral EEG foci, 13 (87%) had right and 2 (13%) had left focus. All of the nine patients who had sufficient data on ictal onset area had right-sided seizure onset. The authors suggest that orgasmic aura is an ictal lateralizing sign to the right hemisphere.

Adult↗
PubMed2002

Synaptic reorganization of calbindin-positive neurons in the human hippocampal CA1 region in temporal lobe epilepsy.

The distribution, morphology, synaptic coverage and postsynaptic targets of calbindin-containing interneurons and afferent pathways have been analyzed in the control and epileptic CA1 region of the human hippocampus. Numerous calbindin-positive interneurons are preserved even in the strongly sclerotic CA1 region. The morphology of individual cells is altered: the cell body and dendrites become spiny, the radially oriented dendrites disappear, and are replaced by a large number of curved, distorted dendrites. Even in the non-sclerotic epileptic samples, where pyramidal cells are present and calbindin-immunoreactive interneurons seem to be unchanged, some modifications could be observed at the electron microscopic level: they received more inhibitory synaptic input, and the calbindin-positive excitatory afferents - presumably derived from the CA1, the CA2 and/or the dentate gyrus - are sprouted. In the strongly sclerotic tissue, with the death of pyramidal cells, calbindin-positive terminals (belonging to interneurons and the remaining excitatory afferents) change their targets. Our data suggest that an intense synaptic reorganization takes place in the epileptic CA1 region, even in the non-sclerotic tissue, before the death of considerable numbers of pyramidal cells. Calbindin-positive interneurons participate in this reorganization: they show plastic changes in response to epilepsy. The enhanced inhibition of inhibitory interneurons may result in the disinhibition of pyramidal cells or in an abnormal synchrony in the output region of the hippocampus.

Adult↗
PubMed2002

Spike-wave discharge and the microstructure of sleep-wake continuum in idiopathic generalised epilepsy.

This review summarises all the evidences about the influence of different vigilance states on the occurrence of spike wave discharge (SWD) in idiopathic generalised epilepsy (IGE) patients. Numerous converging observations showed that full REM-sleep and alert wakefulness exert strong inhibition. A critical zone of vigilance which is a transitional state between waking and non-REM (NREM) sleep, and NREM sleep and REM sleep, has a promoting effect on the absence type spike wave discharge. Spike wave discharges are associated with phasic arousals without awakening and are attached to oscillation son the microstructural level of sleep, perpetuated by cyclic arousal events known as 'cyclic alternating pattern' (CAP), especially within the critical zone, but also along the whole sleep process. More specifically SWD seems to be attached to the 'A-phase' of CAP which is a reactive one and reflects synchronised NREM sleep EEG elements, like K-complexes, spindles and delta groups. The more slow wave elements are found in phase A--like in subtype A1--the more the coincidence with SWD occurs, and the more it is characterised by fast rhythms--as in subtype A2 and A3--the less the association with SWD could be observed. Since subtype A1 is associated with the first sleep cycle and with the descending branches of cycles, it is concluded that SWD appear in those dynamic moments of vigilance level oscillations which were characterised by strong sleep-like answers to arousal influences in high sleep pressure periods of sleep cyclicity. These data harmonize with another line of evidence suggesting that SWD represent the epileptic variant of the complex thalamocortical system function which is the substrate of NREM sleep EEG phenomena. In idiopathic generalised epilepsy there is a growing body of evidence that--as it was assumed by Gloor--spindles transform to SWD pattern. These data explain why those dynamic changes which evoke sleep responses are promoting for the occurrence of SWD. Adapting these data we offer a new interpretation to explain the strong activation effect of sleep deprivation in this kind of epilepsy. We assume that it is mainly due to the forced vigilance level oscillations, especially in morning, when elevated sleep pressure and circadian wake promoting forces, representing opposite tendencies, increase the amount of oscillations.

Epilepsy, Generalized↗
PubMed2002

Number of GABA immunonegative and GABA immunopositive neurons in human epileptic temporal cortex.

The number of neurons, both GABA immunopositive and immunonegative, was determined in temporal epileptic foci of 7 patients after temporal lobectomy, and compared to neuronal numbers in temporal cortex of two controls taken from tumor operated patients. The thickness of the cortex of the epileptic cortex diminished by about 10%, while the number of nerve cells decreased to 67% of that of the control value: it was 19.000/mm(3) vs. 28.000/mm(3) found in the control. This decline was due to cell degeneration, which, however, was more severe for non-GABAergic nerve cells. Accordingly, the proportion of the GABA-positive neurons in the otherwise diminished neuronal population increased to 36.4% from the 32% control value. The number of GABAergic terminals, however, decreased even further, explaining the resulting disinhibition during epileptic seizures.

Epilepsy↗
PubMed2002

Misleading lateralization by ictal SPECT in temporal lobe epilepsy-- a case report.

A 28-year-old woman with temporal lobe epilepsy underwent presurgical evaluation. Scalp-EEG showed non-localizing seizure patterns. MRI revealed a right hippocampal sclerosis. Ictal HMPAO-SPECT showed a marked left temporal hyperperfusion. Video-EEG monitoring with foramen ovale electrodes (FOE) showed an initial seizure pattern which appeared in the right FOE and which shifted to the left 8 s after clinical onset. Three years after a right temporal lobectomy, the patient is seizure-free. In conclusion, although the ictal SPECT suggested a left temporal seizure focus, the intracranial EEG and the postoperative seizure-freedom confirmed the right-sidelocation of the epileptogenic region. A rapid right-left seizure spread explains the mechanism of falsely lateralizing ictal SPECT.

Adult↗
PubMed2001

[Treatment and long-term follow-up of post-anoxic myoclonus].

UNLABELLED: Postanoxic myoclonic (Lance-Adams) syndrome is characterized by myoclonic jerking provoked by intention or external stimuli. The authors present a patient in whom high-dose piracetam treatment resulted in a long-term improvement. Their female patient jumped into the river in order to commit a suicide. She was rescued in the state of clinical death. After a successful reanimation, she was comatose for 16 days. Despite the adequate rehabilitation therapy, her movement status did not change, due to jerking induced by external stimuli. Two months after the asphyxia, the patient was still confined to bed. The authors diagnosed her illness as Lance-Adams syndrome, based on the clinical history and symptoms. Valproic acid and clonazepam was introduced and, after a few days 24 g piracetam was added intravenously. After the first piracetam infusion, the jerking dramatically diminished, she was able to walk with some help. During the 4-years follow up, she received orally 19.2 g piracetam, 1500 mg valproic acid and 6 mg clonazepam. Now she is able to walk without help for a short distance and her cognitive functions have almost completely restituted. CONCLUSION: Lance-Adams syndrome is usually recognized only in a late phase, preventing the early rehabilitation. The trias consisting of anoxia, coma, and stimulus-sensitive myoclonus, however, can be easily recognized, and the adequate treatment may lead to a significant improvement.

Adult↗
PubMed2001

[Surgically treatable epilepsy--a review].

20-25% of epileptic patients do not become seizure free on adequate drug therapy. In 25-50% of patients with intractable epilepsy, the brain area responsible for seizures is well localizable and does not involve eloquent regions. In these patients, the surgical excision of the epileptic focus may lead to relief from seizures. In Hungary, there may be 5-6000 patients who needs an epilepsy surgery, but till now only 200 patients with chronic epilepsy underwent a surgical procedure. In the surgically remediable epilepsies, the operation is not a "ultima ratio". Concerning these syndromes, if 2-3 adequate antiepileptic drugs do not lead to seizure freedom within 1-3 years after the epilepsy onset, then a presurgical evaluation is necessary. The most common surgically remediable epilepsy is the temporal lobe epilepsy in which 60-90% of drug-resistant patients could be surgically cured. In lesional neocortical epilepsies 50-80% of patients become postoperatively seizure free. In childhood hemispheric epilepsies, the surgery could lead to seizure freedom in 70-80% of patients. The basic tools of the presurgical evaluation are the detailed history, the high resolution-MRI, the video-EEG monitoring, and the neuropsychological assessment. These investigation methods are usually enough to evaluate the necessity of the surgery and the postoperative outcome as well as to plan the localization and the extension of the resection. In some cases, ictal SPECT, PET, or video-EEG monitoring with intracranial electrodes could also be necessary in order to localize the epileptic focus.

Algorithms↗