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Biomedical subjects

P Genton

Publications and source records attributed to P Genton.

At least 55 records · Page 3Linked to original sources
PubMed2000

Antimyoclonic effect of levetiracetam.

Treatment of severe, incapacitating action myoclonus is difficult. Piracetam has been shown to be a very potent antimyoclonic agent, but only at very high, impractical doses, ranging from 24 to 40 g/d. Levetiracetam (LEV), a new antiepileptic drug, is a structurally related compound that has a distinct pharmacological profile and appears to be efficient at much lower doses. We gave LEV, 4,000 mg/d, without titration, to three volunteers with post-anoxic myoclonus (PAM) (one case) and Unverricht-Lundborg disease (two cases), over 2, 2 and 10 weeks, respectively. LEV produced a clear abatement of myoclonus, which is demonstrated on video for the patient with post-anoxic myoclonus, without any unwanted side-effects. These preliminary findings suggest that LEV may have interesting antimyoclonic properties that deserve further investigation.

Adult↗
PubMed1999

[Benign epilepsy in children and adolescents].

THE CONCEPT OF BENIGN EPILEPSY: The benign nature of epilepsy is difficult to establish. The diagnosis of epilepsy often has an effect disproportionate to the severity. In everyday practice, most cases of epilepsy follow a benign course. A benign evolution is the rule in certain syndromes which are usually diagnosed early. In other cases however, the benign prognosis cannot be determined except after long-term follow-up. BENIGN EPILEPSY: There are 3 large categories of benign epilepsy: partial idiopathic epilepsy, generalized idiopathic epilepsy, occasional seizures. They are particularly frequent in children and adolescents, but can be observed in the neonatal period and in older patients. DIAGNOSIS OF BENIGN EPILEPSY: A syndromic approach to the problem is required. The patient's history, clinical signs, electroencephalographic data, and in certain cases neuroimaging findings are required for diagnosis. Confirmation of the benign nature of the epilepsy is reassuring for the patient and the family and can avoid unnecessary explorations. The appropriate therapeutic attitude is usually abstention from long-term antiepileptic treatment. It is importance for all clinicians to be familiar with "benign" epilepsy.

Adolescent↗
PubMed1999

Are there generalised spike waves and typical absences in benign rolandic epilepsy?

Generalised 3 Hz spike wave (SW) discharges with or without absences have been described in children with benign epilepsy with centrotemporal spikes (BECTS), leading to speculations about a continuum between childhood absence epilepsy (CAE) and BECTS. We thus decided to evaluate the prevalence of absence seizures (AS) and generalised 3 Hz SW in patients with BECTS. All patients with BECTS first referred since 1986 have been identified prospectively. Their medical and electroencephalograph (EEG) records were analysed retrospectively, in the search for AS and generalised SW discharges. Over a period of 11 years, we found typical rolandic spikes in 66 newly referred patients; 64 had seizures typical for the condition (18 female, 46 male), two were asymptomatic and were not further analysed. All had routine waking EEG recordings, and 49 children (76%) had at least one sleep EEG. AS or classical generalised 3 Hz SW were never recorded from history or EEG data, respectively. However, 17 patients had some diffuse SW discharges, lasting 1-5 s, which appeared as grossly symmetrical in only seven children, with a clearly asymmetrical aspect in the others. Among these seven patients, the discharges were only seen on awakening in one, both during waking and nREM sleep stage I or II in one and only during nREM sleep stage I or II in five. They were apparently subclinical in all. We thus found neither AS nor classical 3 Hz SW discharges among 64 consecutive patients with BECTS. Brief bursts of bilateral abnormalities occur in about 25% of the cases, mostly with sleepiness. Such findings do not substantiate the existence of a continuum between CAE and BECTS.

Child↗
PubMed1999

Piracetam in the treatment of cortical myoclonus.

This paper reviews existing publications on the use of piracetam for the treatment of cortical myoclonus of various etiologies and includes the personal experience of the authors in progressive myoclonus epilepsy. Two double-blind comparisons with placebo provided results which allow recommendations for the dosage and usage of piracetam in cortical myoclonus. Wide individual variation (7-24g daily) exists in dosage requirements but responses are dose-related so that dosage should be increased until an optimum effect is obtained. Tolerability after long-term use of piracetam in high dosage has been very good and without toxicity or serious adverse effects. Side effects have been occasional, mild and transient. The authors present their experience of 12 patients with progressive myoclonus epilepsy in whom the administration of up to 45 g piracetam daily, when added to existing anti-epileptic treatment, caused marked and sometimes spectacular improvement and was without significant adverse effects. Improvement was maintained for up to 7 years. The use of piracetam for disabling cortical myoclonus of any etiology, either as an addition to existing antimyoclonic drugs or as monotherapy, may bring about profound improvement in disability and quality of life. Piracetam should be considered a first-line drug for the treatment of cortical myoclonus.

Clinical Trials as Topic↗
PubMed1999

Benign childhood epilepsy with centrotemporal spikes and hippocampal atrophy.

A boy without significant family or personal history had three consecutive nocturnal seizures at 1-month intervals at age 10 years, all simple focal seizures with motor and sensory symptoms, the last with secondary generalization. Waking and napping EEG showed focal sharp changes typical of benign epilepsy with centrotemporal spikes (BECTS). A magnetic resonance imaging documented a marked right hippocampal atrophy (HA). After valproic acid (VPA) therapy, there were no more seizures, and there were fewer EEG changes. An EEG performed in the younger, fully asymptomatic 8-year-old sister documented unilateral right focal sharp waves. This case shows that HA, as well as other central nervous system lesions, can be found fortuitously in patients with BECTS.

Atrophy↗
PubMed1999

Gamma knife surgery for mesial temporal lobe epilepsy.

PURPOSE: Gamma knife radiosurgery (GK) allows precise and complete destruction of chosen target structures containing healthy and/or pathologic cells, without significant concomitant or late radiation damage to adjacent tissues. All the well-documented radiosurgery of epilepsy cases are epilepsies associated with tumors or arteriovenous malformations (AVMs). Results prompted the idea to test radiosurgery as a new way of treating epilepsy without space-occupying lesions. METHODS: To evaluate this new method, we selected seven patients with drug-resistant "mesial temporal lobe epilepsy" (MTLE). The preoperative evaluation program was the one we usually perform for patients selected for microsurgery of TLE [video-EEG analysis of seizures, foramen ovale electrode recording, magnetic resonance imaging (MRI) positron emission tomography (PET) scan, neuropsychological testing]. In lieu of microsurgery, the amygdalohippocampectomy was performed by using GK radiosurgery. RESULTS: Morphologic (MRI) signs of destruction of the target took place at 9 months after GK surgery. Since the treatment day, the first patient has been seizure free. Seizure improvement came more gradually for the following patients, and complete cessation of seizures occurred around the tenth month (range, 8-15 months). MRI shows that the amygdaloentorhinohippocampal target was selectively injured. No significant side effect (except one case of homologous quadrantanopia) or morbidity and no mortality was observed. The current follow-up is 24-61 months, and all (but one) patients are seizure free. CONCLUSIONS: This initial experience proves clearly the short-to middle-term efficiency and safety of GK for MTLE surgery. These results need further confirmation of long-term efficiency, but the introduction of GK surgery into epilepsy surgery can reduce dramatically its invasiveness and morbidity.

Adult↗
PubMed1999

Is schizophrenia a risk factor for epilepsy or acute symptomatic seizures?

PURPOSE: The precise prevalence of epilepsies and seizures in patients with schizophrenia remains unclear. METHODS: To assess the prevalence of epilepsy and of acute symptomatic seizures in schizophrenics, we conducted a survey in a urban sector of Marseilles that includes 56,910 inhabitants, among whom 1,154 had been treated for psychiatric disorders, including 460 for schizophrenia or paranoid disorder (PD) (DSM III-R 295 and 297.1, respectively; mean age, 41.9 years; range, 17-79 years; 215 men and 245 women). RESULTS: All 460 patients were receiving long-term neuroleptic drug therapy, and 397 had been hospitalized at least once in the past year, whereas 63 were followed up as outpatients only. Seizures were present in the history of 12 patients: five had various forms of chronic epilepsy (four men, one woman; DSM III-R 295.1, one case; 295.3, two cases; 295.9, two cases), and three of these experienced seizures only after the onset of their psychiatric condition; five had acute symptomatic seizures (four men, one woman; 295.1, two cases; 295.3, 295.9, and 297.1, one case), and two had only pseudoepileptic events (both 295.3). CONCLUSIONS: This survey shows that the prevalence of epilepsy and acute symptomatic seizures is comparatively low in patients with schizophrenia or PD (10.8 per thousand each, respectively), and that the prevalence of a history of seizures (21.7 per thousand in this study) is not particularly increased in this middle-aged population. In contrast to childhood-onset autistic disorders, schizophrenia or PD are not major risk factors for epilepsy or acute symptomatic epileptic seizures.

Acute Disease↗
PubMed1999

Late-onset epilepsy associated with regional brain cortical dysplasia.

RATIONALE: Cortical dysplasia (CD) designates a diverse group of malformations resulting from one or more abnormalities in the development of the cerebral cortex. The clinical manifestations of CD are varied, probably depending on the type, location and extent of CD. Epilepsy is a potential late manifestation of any cortical malformation. To our knowledge, however, no study has focused specifically on late onset of epilepsy in patients with localized CD. MATERIAL AND METHODS: We studied patients with localized CD confirmed by MRI. Patients were divided into 2 groups according to age at onset of epilepsy. Group 1 included patients in whom the first seizure occurred up to the age of 12 (early-onset group) and group 2 included patients in whom the first seizure occurred after the age of 12 (late-onset group). The two groups were compared with regard to the type of CD, clinical findings and EEG findings. RESULTS: Thirty-three patients with various forms of CD were studied. Onset of epilepsy occurred in adolescence or adulthood in 9 cases (37%). In 6 of these (17% overall), the first seizure occurred in adulthood. CD were posterior bilateral pachygyria (1), unilateral polymicrogyria (3), focal dysplasia with subcortical gray matter heterotopia (1), perisylvian bilateral polymicrogyria (1), bioccipital polymicrogyria (1) and bilateral nodular periventricular gray matter heterotopia (2). The incidence of neurological signs was lower in the late-onset group. Mental retardation was moderate or absent, thus allowing a fairly normal lifestyle. All patients presented partial seizures with a lower incidence of drug resistance (p < 0.01). EEG demonstrated preservation of background activity and absence of diffuse or multifocal abnormalities. CONCLUSION: Onset of epilepsy with various forms of CD may be delayed until adolescence or adulthood. Prognosis of epilepsy is usually more favorable in these cases.

Adolescent↗
PubMed1999

Radiosurgery for trigeminal neuralgia and epilepsy.

The role of Gamma Knife surgery in the field of functional surgery recently has evolved dramatically. For treatment of trigeminal neuralgia, Gamma Knife surgery is the least invasive procedure, with a low rate of hypesthesia. If a rate of complete relief similar to that of other surgical techniques could be achieved, this approach will become one of the main techniques used to treat the disease initially. The authors present their experience with a group of 16 patients with mesial temporal lobe epilepsy who have been treated successfully (15 completely seizure-free and 1 with rare, nondisabling seizures) without significant complication. After additional follow-up to demonstrate the absence of long-term consequences, this fascinating new approach could change epilepsy surgery practice dramatically.

Adult↗
PubMed1999

[Limitations of the concept of idiopathic generalized epilepsy].

The 1989 International Classification of Epilepsies confirmed the existence of a category of Idiopathic Generalized Epilepsies (IGE), which includes a list of age-dependent syndromes that are supposed to share a common mechanism. Recent clinical, experimental and genetic data have shown that the group of IGEs is indeed heterogeneous, that various mechanisms are implied, and that the limits of this category remain comparatively unclear, especially versus cryptogenic or symptomatic generalized epilepsies. There is no such thing as a truly "generalized" epilepsy, and "idiopathic" means in fact that epileptic seizures are the only, or predominant symptom of the condition. The pharmacological sensitivity (some drugs control IGEs, other drugs usually aggravate them) seems to be common to a majority of the syndromes of IGE. The concept of IGE remains useful in clinical practice, and should be widened to include newly described syndromes.

Age Factors↗
PubMed1999

Non-convulsive status in the ring chromosome 20 syndrome: a video illustration of 3 cases.

We report the clinical history and the video-EEG recordings of three young adults with r(20), who exhibited repeated episodes of non-convulsive status epilepticus, often triggered by emotional events. This recognizable clinical entity associates a slight mental deficiency, behavioural disorder and epilepsy, often resistant to treatment and with a particular clinical presentation. We demonstrate with video EEG recording, atypical absence status triggered by emotional behaviour with ictal EEG characterized by bifrontal slow waves, often rhythmic, or sharp waves. Our report highlights the characteristic features of non-convulsive status in this electro-clinical syndrome.

Adult↗
PubMed1998

[Recommendations for blood studies and clinical monitoring in early detection of valproate-associated liver failure. Results of a consensus conferences 9 May - 11 May 1997 in Berlin].

Valproate is a frequently used antiepileptic drug. It is associated with rare but serious adverse effects like liver failure. The first symptom is impairment of the patient's well being. Isolated changes of standard laboratory liver parameters are not reliable early indicators. Thus, according to the knowledge of today, prophylactic blood screening cannot predict complications. On the contrary, clinical symptoms are the most relevant indicators of impending complications, eventually supported by laboratory findings. An abrupt withdrawal of valproate and administering carnitin in parallel can interrupt the otherwise fatal course of the complication and induce a subsequent recovery. At a Consensus Conference the current knowledge about early detection and therapy of the valproate-induced serious hepatotoxicity was discussed. The results regarding recommended laboratory screening, as well as diagnostic and therapeutic strategies are reported.

Adolescent↗
PubMed1998

Seizures in Klinefelter's syndrome.

This study describes the clinical spectrum of patients with Klinefelter's syndrome and seizures. Klinefelter's syndrome is a sex chromosomal abnormality and the most common cause of male hypogonadism. It is characterized by cognitive dysfunction, hypogonadism, and abnormalities of physical maturation. Neurologic impairment has been recognized, but seizures have received little attention. The authors describe three American patients and discuss nine additional patients from two European centers previously reported with Klinefelter's syndrome and seizures. The most common profile of patients with Klinefelter's syndrome and seizures includes mental retardation, behavior problems, epileptiform electroencephalograms (EEGs), and generalized tonic-clonic seizures. The seizures of six of 11 patients with epilepsy were well controlled with antiepileptic drugs. One patient had a single seizure and was not treated with medication. In patients with Klinefelter's syndrome and recurrent seizures, the electroclinical spectrum is heterogenous and outcome with antiepileptic drug treatment is favorable.

Adolescent↗
PubMed1998

A PCR amplification method reveals instability of the dodecamer repeat in progressive myoclonus epilepsy (EPM1) and no correlation between the size of the repeat and age at onset.

Progressive myoclonus epilepsy of the Unverricht-Lundborg type (EPM1) is a rare, autosomal recessive disorder characterized by onset at age 6-16 years, generalized seizures, incapacitating myoclonus, and variable progression to cerebellar ataxia. The gene that causes EPM1, cystatin B, encodes a cysteine proteinase inhibitor. Only a minority of EPM1 patients carry a point mutation within the transcription unit. The majority of EPM1 alleles contain large expansions of a dodecamer repeat, CCC CGC CCC GCG, located upstream of the 5' transcription start site of the cystatin B gene; normal alleles contain two or three copies of this repeat. All EPM1 alleles with an expansion were resistant to standard PCR amplification. To precisely determine the size of the repeat in affected individuals, we developed a detection protocol involving PCR amplification and subsequent hybridization with an oligonucleotide containing the repeat. The largest detected expansion was approximately 75 copies; the smallest was approximately 30 copies. We identified affected siblings with repeat expansions, of different sizes, on the same haplotype, which confirms the repeat's instability during transmissions. Expansions were observed directly; contractions were deduced by comparison of allele sizes within a family. In a sample of 28 patients, we found no correlation between age at onset of EPM1 and the size of the expanded dodecamer. This suggests that once the dodecamer repeat expands beyond a critical threshold, cystatin B expression is reduced in certain cells, with pathological consequences.

Adolescent↗
PubMed1998

Carbamazepine intoxication with negative myoclonus after the addition of clobazam.

We report a case a carbamazepine (CBZ) intoxication with negative myoclonus that occurred 4 weeks after clobazam (CLB) had been added to a stable regimen of CBZ and topiramate (TPM). Both CBZ and CBZ-epoxide (CBZ-E) blood levels were elevated, and the symptoms resolved quickly when CBZ dosage was reduced and CLB discontinued. CLB was reintroduced a year later with the patient's consent, and the time course of the interaction was studied: CBZ and CBZ-E levels increased slowly over 12 days. The interaction is thus probably related to the progressive increase in Nor-CLB.

Aged↗
PubMed1998

Lamotrigine and seizure aggravation in severe myoclonic epilepsy.

PURPOSE: In severe myoclonic epilepsy of infancy (SME), multiple drug-resistant focal and generalized seizure types occur. Lamotrigine (LTG), found effective in many generalized and partial seizures, has been little used in severe childhood epilepsy syndromes with multiple seizure types. We studied the effects of LTG in SME. METHODS: Twenty-one patients with SME, aged 2-18 years, were treated with LTG, 20 in add-on and one in monotherapy. LTG was started at 0.2-2.5 mg/kg/day and increased to 2.5-12.5 mg/kg/day. For each seizure type, excluding atypical absences, >50% variations compared with the 2 months preceding LTG were considered indicators of response, also taking into account the degree of disability each seizure type produced. RESULTS: LTG induced worsening in 17 (80%) patients, no change in three, and improvement in one. There was >50% increase in convulsive seizures in eight (40%) of 20 patients. Myoclonic seizures worsened in six (33%) of 18 patients. Of five patients improving in at least one seizure type, four had concomitant worsening of more invalidating seizures. Clear-cut worsening appeared within 3 months in most patients but was insidious in some. LTG was suspended in 19 patients after 15 days-5 years (mean, 14 months) with consequent improvement in 18. CONCLUSIONS: The pronounced seizure deterioration during LTG treatment was not attributable to the natural course of the disease and could be a direct effect of therapeutic LTG doses. LTG treatment seems inappropriate in SME.

Acute Disease↗
PubMed1998

Antiepileptic drug-induced worsening of seizures in children.

Antiepileptic drugs (AEDs) may aggravate pre-existing seizures and trigger new seizure types. However, the extent and mechanisms of this problem are unclear, for several reasons. AED trials are not designed to detect worsening of seizures, severe childhood epilepsies may fluctuate in severity, and worsening of seizures may be over-hastily ascribed to the introduction of a new AED. Moreover, the seizure and the epilepsy type may have been incorrectly diagnosed. The problem is identification of true aggravation of epilepsy in the absence of overdosage or toxicity. This is a common and clinically important problem that concerns both established and newer AEDs, but the biologic mechanisms involved are unknown. An increase in seizure frequency due to overdosage has been reported with phenytoin but is rare with other AEDs. Paradoxical reaction has been reported with carbamazepine (CBZ), benzodiazepines, and vigabatrin (VGB). Exacerbation of seizures may also occur during AED-induced encephalopathy or hepatopathy. An inappropriate choice of the AED (i.e., a purely pharmacodynamic mechanism) can induce worsening when CBZ or VGB is used in absence and myoclonic seizures. Further research should determine whether seizure exacerbation is associated with the type of epilepsy or with the type of EEG abnormality. Recent evidence indicates that lamotrigine is inappropriate in severe myoclonic epilepsy. Some childhood epileptic encephalopathies have been affected by certain seizure-worsening mechanisms. Whether this is due to a predisposition in specific syndromes or to an increased risk for adverse effects in patients undergoing multiple AED manipulations is unclear. Furthermore, some syndromes are not the sum of accompanying seizure types but have unique neurobiology.

Acute Disease↗