Acquired epileptiform aphasia

Childhood autism spectrum disorders with and without epilepsy: clinical implications

This prospective cross-sectional study compared 25 children with pervasive developmental disorder and epilepsy and 25 children having pervasive developmental disorder without epilepsy on pervasive developmental disorder scores, Childhood Autism Rating Scale scores, language disability, presence of regression, and epileptiform abnormalities. Epilepsy phenotype was also studied. Children with pervasive developmental disorder and epilepsy had higher pervasive developmental disorder scores (P = .001), higher Childhood Autism Rating Scale scores (P = .016), and lower social quotient (P = .09). More than 50% of children with pervasive developmental disorder and epilepsy and 12% of children having pervasive developmental disorder without epilepsy had epileptiform abnormalities in electroencephalography (EEG). Regression of milestones was significantly associated with epilepsy and epileptiform abnormalities. Children with pervasive developmental disorder and epilepsy might have a worse developmental trajectory requiring intensive management. A behavioral phenotype of autism may coexist often in children with epilepsy, EEG abnormalities, and regression. Seizures might be difficult to control in these children despite adequate compliance. Studies with larger sample size and longitudinal follow-up will provide better understanding.

Epileptiform discharges augmented during sleep: is it a trait with diverse clinical presentation according to age of expression?

Sleep has long been viewed as a negative phenomenon; however, it is now clear that it is a period of intense brain activity involving higher cortical functions. Overall, sleep affects every aspect of a child's development, particularly higher cognitive functions. The seizure threshold is often affected by changes in the level of arousal, and many interictal EEG abnormalities are activated by sleep. Epileptiform discharges augmented during sleep are described in number of epileptic syndromes characterized by infrequent clinical seizures but significant cognitive deterioration, the prototype of which is the syndrome of continuous spike-wave discharges during sleep (CSWS). In this article the conditions sharing the same EEG feature of paroxysmal epileptiform discharges augmented during sleep and their overlap will be highlighted arguing whether these disorders may be clinical presentations of same trait when expressed at different stages of brain maturity, as well as the controversies in definition and management of cases without clinical seizures.

Electrical status epilepticus in sleep

Electrical status epilepticus in sleep (ESES) describes an electroencephalographic pattern showing significant activation of epileptiform discharges in sleep. The terms continuous spike wave in slow-wave sleep (CSWS) and Landau-Kleffner syndrome (LKS) describe the clinical epileptic syndromes seen with ESES. Although there is an overlap between these 2 syndromes, children with CSWS present with a more global regression have more problematic epilepsy and have EEG foci located predominantly in frontotemporal or frontocentral regions. In contrast, children with LKS present with an acquired auditory agnosia, fewer seizures, and EEG foci in the posterotemporal regions. ESES requires a high degree of clinical suspicion because slow-wave sleep must be recorded to confirm this diagnosis. Treatment of ESES extends beyond just control of the seizures; amelioration of the continuous epileptiform discharge must occur to improve neuropsychological outcome. Although there is little evidence to guide treatment, conventional antiepileptic drugs play only a minimal role. Steroid therapy and high-dose benzodiazepines are most commonly used, but other therapies including intravenous gamma-globulin, the ketogenic diet, and surgical therapy with multiple subpial transaction have shown efficacy in small case series. Although epilepsy resolves with time in most cases, many children are left with significant cognitive or language impairment. Longer duration of ESES appears to be the major predictor of poor outcome; markedly abnormal neuronal activity during a critical period for synaptogenesis may result in aberrant synapse formation, explaining the poorer neuropsychological outcome. Early recognition and effective therapy are necessary to improve long-term prognosis in this condition.

Landau-Kleffner syndrome with lateral temporal focal cortical dysplasia and mesial temporal sclerosis: a 30-year follow-up

A 39-year-old man, who presented at age 312 with Landau-Kleffner syndrome, had persisting oral and written language deficits into adulthood. Seizures were easily controlled in childhood, but reemerged in adulthood as medication-refractory complex partial seizures. Abnormal T2 signal hyperintensity was seen in the left mesial temporal area on brain MRI. Later, left temporal lobectomy revealed focal cortical dysplasia in the lateral temporal neocortex and gliosis plus neuronal loss in the hippocampus. This case suggests that focal cortical microdysgenesis may be a cause of the Landau-Kleffner syndrome. Persistent seizures in this illustrative case may have led to the evolution of dual-temporal-lobe pathology with mesial temporal sclerosis.

Prevalence of childhood disintegrative disorder

The prevalence of childhood disintegrative disorder (CDD) is unknown. In this study, 32 epidemiological surveys of autism and pervasive developmental disorders published in English language journals since 1966 were reviewed. Four surveys yielded estimates for CDD ranging from 1.1 to 6.4 per 100,000 subjects. A pooled estimate across these four surveys is 1.7 per 100,000 (95 percent Confidence Interval: 0.6-3.8 per 100,000). The conclusion is that CDD is very rare and its prevalence is 60 times less than that for autistic disorder, assuming a prevalence of 10 per 10,000 for autism. If a rate of 30 per 10,000 is taken for all PDDs, only one child out of 175 children with a PDD diagnosis would, on average, meet criteria for CDD.

Treatment of seizure disorders and EEG abnormalities in children with autism spectrum disorders

The treatment of seizure disorders EEG epileptiform abnormalities without epilepsy in children with autism spectrum disorders (ASD) is considered within the context of the relationship of epilepsy and epileptiform disorders to language, behavior, and cognition. There is an increased prevalence of both epilepsy and abnormal potentially epileptogenic activity in children with ASD. Anecdotal evidence suggests that the use of anticonvulsants to treat epileptiform discharges thought to be producing dysfunction in selected aspects of cognition, language, or behavior makes a positive difference in a subgroup of children with ASD, but there is inadequate evidence on which to base specific recommendations. There is, at present, no scientific justification for considering epilepsy surgery in children with ASD in the absence of intractable clinical seizures.

Persistent occipital electrographic status epilepticus

A 13-year-old girl of normal intellect had clinically silent occipital electrographic status epilepticus that persisted for more than 3 years. Neurologic examination and cranial magnetic resonance imaging were entirely normal. [18F]Fluorodeoxyglucose positron emission tomography demonstrated a hypermetabolic focus in the right occipital lobe. Electrographic status lasting years can be seen in epilepsia partialis continua. However, the absence of focal clinical seizures, nonprogressive course, and normal magnetic resonance imaging study seen in this patient are not features characteristic of epilepsia partialis continua.

Autism and autistic epileptiform regression with occipital spikes

The electroencephalographic abnormalities seen in Landau-Kleffner syndrome (LKS) (language deterioration) are non-specific, and consist of a variety of epileptiform discharge patterns including continuous slow spike-wave discharges during sleep, focal sharp waves with spikes, and centrotemporal (rolandic) spikes. Similarly, the EEG abnormalities seen in autistic epileptiform regression (language and social/behavioral deterioration) are non-specific and overlap with those seen in LKS. By contrast, distinct epilepsy syndromes in otherwise normal children occur in the EEG-defined benign focal epilepsies of childhood. Occipital spikes or spike-wave present either in the older child with visual symptoms and headache or in the younger child with autonomic symptoms followed by brief or prolonged partial motor seizures. Seven young children (five from a consecutive series of 42) presenting clinically with autism or autistic regression and possible or definite seizures, whose EEGs revealed occipital spikes or spike-wave characteristic of the benign epilepsies, are reported. Although occipital spikes are commonly seen in young children as an age-dependent EEG-defined benign focal epilepsy, their high frequency in this population with cognitive difficulties suggests a possible causal relation. The effects of the epileptiform discharge on cognitive functioning presumably reflect extension into temporal and parietal lobes, rather than occipital disturbances per se.

Electroencephalogram in developmental delay: specific electroclinical syndromes

The electroencephalogram (EEG) plays an important role in the evaluation of a child with developmental delay. An EEG is often required to classify seizures in children with developmental delay. Equally important is the role of the EEG in the identification of specific electroclinical syndromes in children who may or may not manifest seizures. Specific electroclinical syndromes include the acquired epileptiform aphasia syndrome, Landau-Kleffner syndrome, and electrical status epilepticus during slow wave sleep. Other clinical situations where the EEG offers diagnostic and prognostic information, such as subacute sclerosing encephalitis, progressive myoclonus epilepsies, Rett syndrome, and Lennox Gastaut syndrome are also discussed.