Idiopathic localizationrelated epilepsies

Benign partial epilepsy of childhood

The syndrome of benign partial epilepsy of childhood (BPEC) is also called benign rolandic epilepsy (BRE) and benign epilepsy of childhood with centrotemporal spikes (BECTS). The natural history is favourable for normal neurological and cognitive function plus eventual remission of epilepsy in more than 97% [50]. It is characterized by the onset of usually infrequent partial seizures between ages 3 and 13 years. The temporal distribution of seizure favours nocturnal occurrence but seizures occur any time of day [51]. An autosomal dominant variant has been described [52], The medical history is positive for prior febrile seizures in 10% or less, and family history is positive for seizures of various types in 40%. According to some physicians half of these cases do not warrant treatment [53],

Although patients with BPEC are typically lesion-free, findings that have been reported in patients who manifest the phenotype include hippocampal atrophy [54], cortical dysplasia [55], lesions of corpus callosum, porencephalic cysts and toxoplasmosis [56], Of course once a lesion is found, the diagnosis of BPEC usually needs to be changed.

The distinctive seizure type is simple partial often with onset in the face and orobuccal area variably followed by secondary generalization. The ictus may be sensory or motor or a combination of the two. Ictal phenomena include clonic jerking, speech arrest, drooling and unilateral tonic or clonic convulsions or merely episodic dysarthria and drooling [57,58]. In most cases consciousness is preserved until the seizures secondarily generalize [59], Typically, examination is normal whereas the EEC is demonstrably abnormal due to focal spikes which originate most often in the centrotemporal regions, although on repeated EEG recordings, the spikes often wander [60], When centrotemporal spikes are discovered incidentally in EEGs of children who have not had seizures, most of the children do not go on to have seizures subsequently [61 ]. In approximately 25% of cases, the EEG occasionally reveals generalized spike-waves [62].

Although the natural history of typical BPEC is for remission of epilepsy and normal development [63,64], numerous reports describe children whose courses deviate from a benign pattern in terms of seizure frequency, seizure severity and occurrence of neuropsychological problems [65-68]. Fejerman et al. described 26 children who had atypical evolutions of their epilepsies after presenting with typical clinical pictures of BPEC [69]. Twelve developed atypical benign partial epilepsy; three developed acquired epileptic aphasia (Landau-Kleffner syndrome); seven had bouts of status epilepticus; and five evolved mixed pictures of these atypical patterns.

The overlap of BPEC with other epileptic syndromes of childhood illustrates how the boundaries between syndromic entities are blurred and often indistinct. Some cases that present as BPEC evolve into more complicated clinical problems blending into phenotypes overlapping with LGS, Landau-Kleffner and electrical status epilepticus in slow-wave sleep (ESES) [70-72]. There are cases that have been labelled atypical benign partial epilepsy (ABPE) or pseudo-Lennox syndrome. Atypical features include bouts of status epilepticus, atypical absence seizures, atonic seizures [69,73] and cognitive and behavioural impairment combined with an EEG pattern of slow spike-wave —all of this along with the core feature of partial seizures. Some investigators have correlated the occurrence of cognitive impairment in BPEC to the abundance of paroxysmal EEG activity [74],

Benign partial epilepsy in infancy

Benign partial epilepsy in infancy as first described by Watanabe et al. in 198 7consists of complex partial seizures appearing in infancy with normal interictal EEG patterns awake and asleep [75], Subsequently infants were identified who had both complex partial seizures and secondarily generalized seizures in various combinations [5,76] and later still cases were found with vertex spike-wave patterns during sleep [77], Among those who had developed normally through the age 2 years, 90% continued to develop normally when evaluated at age 5 years [78].

Childhood epilepsy with occipital paroxysms

Described by Gastaut in 1950, this disorder has prominent occipital epileptiform spike-wave activity that appears after eye closure and is suppressed by eye opening [79,80]. Clinical features include visual symptoms such as hemianopsias and amaurosis, abstract and complex structured visual hallucinations along with seizures (simple and complex partial, and/or generalized convulsions) and prominent postictal symptoms with migraine headaches accompanied by nausea and vomiting. Subsequent reports indicated that the original cases described by Gastaut were rare and differed from the norm. The picture that emerged as more typical had variable features that included cases of severe epilepsy, epilepsy confounded by cognitive difficulties and lesional/symptomatic aetiologies which in some cases such as mitochondrial encephalopathy with lactic aci-daemia and stroke (Melas) were progressive [81] These exceptions notwithstanding, authoritative opinions regarding this condition emphasized an excellent prognosis. Key features include onset around age 5 years of episodic vomiting, eye deviation and impaired consciousness with variable secondary generalized convulsions. Most seizures are nocturnal. Most affected children have occipital spikes on EEG, but 20% may have spikes elsewhere or not at all [82],

Reading epilepsy

This rare, benign, non-progressive syndrome is characterized by reading-provoked sensorimotor symptoms affecting the oral-buccal-lingual-facial muscles that are involved in reading aloud [83], However, reading aloud usually is not required to trigger the seizures. As a result, some authorities have recommended renaming the condition language-induced epilepsy [84]. The condition is accompanied by a positive family history of a similar disorder in as many as one fourth of cases. Described by observers as myoclonic, jerking or tonic movements of the jaw, patients report sensations such as stiffness, numbness or tightness during the seizures. A pubertal or postpubertal disorder, the average age of onset is 17 years with symptoms starting as young as 10 years of age in some people [85], Cases have been described that overlap clinically with BPEC, with juvenile myoclonic epilepsy (JME) and with absence epilepsy [86-88].

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