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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Lennox-Gastaut syndrome (LGS) is an electro-clinical syndrome of early childhood that consists of mental retardation, intractable generalized epilepsy with multiple seizure types, and typical EEG findings. We report a 64-year-old woman who was referred for presurgical evaluation with a diagnosis of intractable temporal lobe epilepsy since the age of 14 years, consisting of staring and unresponsiveness, sudden falls, and generalized convulsions. The average seizure frequency was 1-4 per month. Mental status and neurological examination were normal. There was no known etiology and magnetic resonance imaging (MRI) of the brain was normal. Interictal EEG showed findings characteristic of LGS: generalized slow spike-wave complexes, multifocal sharp waves, generalized polyspikes and paroxysmal fast activity during sleep. Despite the absence of mental retardation and the presence of normal alpha rhythm, the patient fulfills most diagnostic criteria for LGS, with unusually late onset and extremely delayed diagnosis. This case illustrates the controversial nosologic boundaries of the syndrome. Prolonged EEG video monitoring may be of value even in the elderly. The LGS and other varieties of secondary generalized epilepsy should be considered in the syndromic diagnosis of epilepsy in the elderly.
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PMID:Lennox-Gastaut syndrome in the elderly? 781 93

Clinical course and results of therapy were analysed in the group of 92 children, aged between 3 and 9 years, with diagnosed Lennox-Gastaut syndrome. The obtained results of an analysis have shown that Lennox-Gastaut syndrome origin is not clear--causative factor can not be established in 1/3 of patients whereas in 1/2 of them abnormal course of pregnancy and perinatal period is noted. Together with seizures of various origin, other focal neurological symptoms, mental retardation and abnormalities in CT scans of the brain are frequently seen in patients with Lennox-Gastaut syndrome. Clinical course, prognosis and results of therapy are largely dependent on the degree of mental development before the onset of epileptic seizures, course of pregnancy and perinatal period, and the time of therapy. Children with Lennox-Gastaut syndrome require relative polytherapy in which valproic acid derivatives are predominating together with benzodiazepines, and temporary corticosteroids. An improvement was achieved in about 30% of the treated children. Prognosis in the remaining 70% of children is rather poor. Irregular administration of drugs, frequent changes of anti-epileptic agents, too low doses and abnormal environmental effects (abnormal parental attitudes) affect the results of therapy. An emphasis is on the poor prognosis in Lennox-Gastaut syndrome proceeded with West syndrome.
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PMID:[Lennox-Gastaut syndrome--clinical course and therapy]. 802 51

We describe three female patients (aged 10, 11 and 21 years) with a Magnetic Resonance appearance of band heterotopia, a diffuse neuronal migration disorder, also known as double cortex syndrome. The clinical picture was characterized by the association of epilepsy and mental retardation in all three cases, as has been previously described in patients with double cortex syndrome. The epileptic syndrome (Lennox-Gastaut syndrome in one case, and symptomatic partial epilepsy in the other two), the response to medical treatment, and the severity of mental retardation were markedly different in the three patients. No clear-cut relationship was found between the clinical picture and the severity of the neuronal migration disorder, as revealed by magnetic resonance imaging. In the three cases, EEG shares some common features: multifocal epileptic activity with frequent bilateral diffusion, and high-amplitude anterior fast activity, intermingled in two patients with bursts of repetitive spikes.
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PMID:Double cortex syndrome: electroclinical study of three cases. 820 43

Pediatric epileptology is very different from adult epileptology. Although some epileptic disorders occur in both children and adults (e.g., localization-related epilepsy with complex partial seizures and primary generalized epilepsy with tonic-clonic seizures), other disorders can be called the catastrophic epilepsies of childhood (e.g., infantile spasms and the Lennox-Gastaut syndrome). They occur, or at least begin, exclusively in childhood and are often associated with mental retardation. Many of these pediatric disorders are notoriously unresponsive to currently available antiepileptic drugs (AEDs). Although there are undoubtedly many reasons for this, one possible explanation is that the methods used to screen potential AEDs use animal models of adult epilepsy. No screening program uses an animal model of seizures that begin during development and lead to functional decline.
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PMID:Investigational antiepileptic drugs for the treatment of childhood seizure disorders: a review of efficacy and safety. 827 78

Some chromosomal abnormality syndromes carry a higher risk of seizures than that found in the general population. Down's syndrome is considered to be the first and the most frequent chromosomal abnormality causing mental retardation. In spite of numerous reports and epidemiological surveys, the outcome of epileptic syndromes in patients with Down's syndrome (DS) is still largely unknown. We retrospectively studied 34 DS patients with epilepsy (14M; 20F). Epileptic syndromes were classified as: infantile spasms, 10 cases, i.e. 31%; Lennox-Gastaut syndrome, 5 cases, 15.5%; symptomatic generalized epilepsy, 1 case; idiopathic generalized epilepsy, 6 cases, 17.6%; partial symptomatic epilepsy, 10 cases, i.e. 31%. In 2 patients the epilepsy was unclassifiable. In all the patients the following evolutive particularities were noted: a) the infantile spasms to have a relatively mild prognosis, as 8/10 patients remained seizure-free, 3 of whom without treatment; b) no patient experienced febrile convulsions prior to the onset of epilepsy; c) Lennox-Gastaut syndrome had a relatively late onset (mean age 10 years, range 8-11.5); d) 7 patients (20.6%) developed reflex seizure. The fragile X syndrome is considered to be the second most frequent chromosomal abnormality causing mental retardation. The prevalence of epilepsy varies from 9.1% to 45% in the different series. In order to evaluate the prevalence rate of epilepsy and the previously hypothesized association with a particular electroclinical picture, we retrospectively studied 90 fragile X syndrome patients (80M, 10F) aged 4 to 25 years (mean age 13y6m).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[The evolution of epilepsy in the most common genetic forms with mental retardation (Down's syndrome and the fragile X syndrome)]. 841 89

Active epilepsy was assessed in all children aged 0-16 years in an area of northern Sweden with about 250,000 inhabitants and around 50,000 children in the age group. One hundred and fifty-five children fulfilled the criteria of active epilepsy giving a prevalence rate of 4.2/1000. The proportion of boys to girls was 1:1.1. This dominance of girls had also been seen in a prospective study of incidence of epilepsy in the same area. Partial seizures were more common than generalized. Among the syndromes benign childhood epilepsy with centrotemporal spikes occurred in 17.4%, absence epilepsy in 6.5% and Lennox-Gastaut syndrome in 5.8%. Children with neurodeficit (ND) more often had generalized epileptic syndromes while the non-ND groups more often had localisation related syndromes. The aetiology was regarded to be remote symptomatic in 42%, idiopathic in 28% and cryptogenic in 30% of the children. Almost all children were on antiepileptic treatment, three quarters of them on monotherapy. Neurodeficit was noted in 42%. The prevalence of epilepsy and mental retardation was 1.7/1000. Relatively few children with neurodeficit had been seizure free during the last year, 43% had more than one seizures per month compared to 19% in the non-ND group.
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PMID:Prevalence and characteristics of epilepsy in children in northern Sweden. 879 30

After a short historical review, the symptomatology of the Lennox-Gastaut syndrome (LGS) as described in the past 30 years is summarized. Next, all papers published in the past 25 years and presenting the author's own patients are critically reviewed. These considerable patient data enabled to some extent supplementary statistical evaluation of the symptoms and signs of LGS. However, only three of the papers reported largely similar symptom complexes whose components were often combined. While not adequate to allow statistical evaluation, these data have been reviewed with descriptive analysis. The resulting diagnostic criteria correspond to those established by Gastaut in 1982 and are convincing because of their frequency of appearance. In addition, they confirm the 1989 description of LGS by the Commission on Classification and Terminology of the International League Against Epilepsy. These criteria and their frequency are: (1) diffuse slow spike waves in the EEG (100%). (2) tonic seizures (94%), (3) atypical absences (80%), (4) runs of rapid spikes in NREM sleep (approx. 70%), (5) status epilepticus (60%), (6) atonic seizures (43%). Resistance to therapy and persistence of epilepsy are amongst the most frequent features. Mental retardation is a leading symptom, occurring on average in 90% of cases. Reliable statistical analysis of the electroclinical data should be performed following the numerical taxonomy and should provide nosological entities and classifications based on objective, reliable and logical fundamentals. This is an indispensable prerequisite for differential diagnosis. Sections follow which discuss recent morphological and neurometabolic findings concerning the etiology as well as the genetics of LGS. The discussion of the differential diagnosis outlines the nosological delineation of LGS from epilepsy with myoclonic-astatic seizures, benign partial epilepsy of childhood with centrotemporal sharp waves, certain focal epilepsies of the frontal and temporal lobe. Lastly, the myoclonic variant of LGS is discussed. This review shows how frequently in the past LGS was investigated using deficient methodology. Additional studies should be undertaken in collaboration with experienced statisticians in order to complement the above analysis of the syndrome.
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PMID:[Nosology of Lennox-Gastaut syndrome]. 885 Dec 92

Seizure-inducing effects can be observed in the treatment of epileptic patients with antiepileptic drugs (AED). This may be a paradoxical reaction (for example the increase of complex focal seizures due to carbamazepine, vigabatrin or phenytoin treatment) or a result of AED-induced encephalopathy (commonly induced by valproate in patients with complex focal seizures). A seizure increase during intoxication with AED is a rare phenomenon, thus, it is not directly related to this condition. An incorrect choice of drugs in the treatment of an epileptic syndrome or seizure type may provoke seizures (as for example the provocation of absences due to carbamazepine or phenytoin). The possible seizure-inducing effect of AEDs has to be differentiated from seizure occurrence due to the natural course of epilepsy. This may be especially difficult in patients suffering from West syndrome or Lennox-Gastaut syndrome, in whom seizure frequency may vary even without medication. However, especially in these patients, drug-induced worsening of seizure manifestation is often observed. In general, a seizure-inducing effect of antiepileptic drugs has to be considered when a seizure increase is observed soon after the initiation of therapy, when a stepwise increase of the dosage is followed by a further increase of seizures, a decrease of seizures is seen with tapering of the dosage and a renewed increase of seizures can be observed after this therapy has been reestablished. Finally, one knows that the clinical condition of encephalopathy due to valproate or carbamazepine is accompanied by seizure increase. In spite of these clinical aspects, the underlying mechanisms of seizure increase mostly remain unclear. From animal experiments it is obvious that especially carbamazepine and phenytoin may provoke generalized seizures as absences or myoclonic seizures. A seizure increase during vigabatrin therapy has been attributed to the increase of the cerebral amount of gamma-amino butyric acid, which is known to possibly exhibit inhibitory or excitatory neuronal effects. The occurrence of tonic seizures in patients with Lennox-Gastaut syndrome has been attributed to the sedative effect of the drugs; however, this conclusion is controversial. From a clinical point of view, one should consider young age of the patient, mental retardation, antiepileptic polytherapy, high frequency of seizures or prominent epileptic activity in the electroencephalogram previous to medication as risk factors for a possible seizure-inducing effect of antiepileptic drugs.
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PMID:Seizure-inducing effects of antiepileptic drugs: a review. 901 23

Mental retardation is detected in 20-30% of children with epilepsy at hospitals specializing in treatment of childhood epilepsy. However, the incidence of mental deterioration in childhood epilepsy is not high. In this study, mental deterioration was found in 52 (1.8%) of the 2,880 children with epilepsy at Okayama University Hospital. The patients showing mental deterioration mostly suffered from specific epileptic syndromes, such as West syndrome, Lennox-Gastaut syndrome, severe myoclonic epilepsy in infancy and epilepsy with continuous spike-waves during slow wave sleep. These types of epilepsy show generalized electroencephalographic (EEG) abnormalities. It is presumed that mental deterioration is caused by the total effects of prolonged diffuse EEG abnormalities and the age of the patients. Antiepileptic drugs exert a relatively minor effect on mental deterioration.
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PMID:Mental deterioration in childhood epilepsy. 928 65

A 9-year-old male with congenital bilateral perisylvian syndrome is described. He had pseudobulbar palsy, mental retardation, and intractable epilepsy. Computed tomography and magnetic resonance images of the brain demonstrated bilateral perisylvian malformations and a diffuse pachygyric appearance. At 8 years of age, he had episodes of excessive drooling, fluctuating impairment of consciousness, unsteady sitting, and frequent head drop that lasted several days. The electroencephalogram demonstrated continuous diffuse slow spike and waves. These findings suggested atypical absence status epilepticus. Intravenous administration of diazepam resulted in transient improvement of clinical and electroencephalographic findings. Status epilepticus recurred within several minutes after diazepam administration. Although no patient has been reported to have a history of status epilepticus among those affected by this syndrome, it seems that atypical absence status can occur more frequently than expected, as seen in Lennox-Gastaut syndrome. After recognition and confirmation of nonconvulsive status epilepticus, immediate treatment must be attempted.
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PMID:Nonconvulsive status epilepticus in a child with congenital bilateral perisylvian syndrome. 1046 49


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