Page 89 - ILAE_Lectures_2015

Chapter 9

Benign childhood seizure susceptibility syndromes

MICHALIS KOUTROUMANIDIS and CHRYSOSTOMOS PANAYIOTOPOULOS

Department of Clinical Neurophysiology and Epilepsies, St Thomas’ Hospital, Guy’s and St
Thomas’ NHS Foundation Trust, London
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Introduction

Benign childhood focal seizures and related idiopathic epileptic syndromes affect 25% of
children with non-febrile seizures and constitute a significant part of the everyday practice of
paediatricians, neurologists and electroencephalographers. They comprise three identifiable
electroclinical syndromes recognised by the International League against Epilepsy (ILAE)1:
rolandic epilepsy which is well known; Panayiotopoulos syndrome (PS), a common autonomic
epilepsy, which is currently more readily diagnosed; and the idiopathic childhood occipital
epilepsy of Gastaut (ICOE-G) including the idiopathic photosensitive occipital lobe epilepsy, a
less common form with uncertain prognosis. There are also reports of children with benign
focal seizures of predominantly affective symptoms, and claims have been made for other
clinical phenotypes associated with specific inter-ictal EEG foci, such as frontal, midline or
parietal, with or without giant somatosensory evoked spikes (GSES). Neurological and mental
states and brain imaging are normal, though because of their high prevalence any type of benign
childhood focal seizures may incidentally occur in children with neurocognitive deficits or
abnormal brain scans. The most useful diagnostic test is the EEG. In clinical practice, the
combination of a normal child with infrequent seizures and an EEG showing disproportionately
severe spike activity is highly suggestive of these benign childhood syndromes2.

All these conditions may be linked together in a broad, age-related and age-limited, benign
childhood seizure susceptibility syndrome (BCSSS) which may be genetically determined3.
Details of original studies, numerous case histories and published reports not cited here can be
found in our previous reviews2,4-7.

Rolandic epilepsy (benign childhood epilepsy with centrotemporal spikes)

Rolandic epilepsy is the best known and commoner benign childhood focal epilepsy2,8-11. The
age of onset ranges from one to 14 years with 75% starting between 7–10 years. There is a 1:5
male predominance, prevalence is around 15% in children aged 1–15 years with non-febrile
seizures and incidence is 10–20/100,000 children aged 0–15 years12-17.

Clinical manifestations
The cardinal features of rolandic epilepsy are focal seizures consisting of unilateral facial
sensory-motor symptoms (30% of patients), oro-pharyngo-laryngeal symptoms (53%), speech
arrest (40%) and hypersalivation (30%)2,8-11,18-20. Ictal manifestations indicative of temporal
lobe involvement do not occur in rolandic epilepsy, and the term ‘centrotemporal’ refers only
to the spike topography, partly a misnomer (see EEG section below). Hemifacial sensory-motor
seizures are mainly localised in the lower lip and may spread to the ipsilateral hand. Motor
manifestations are clonic contractions sometimes concurrent with ipsilateral tonic deviation of
the mouth, and sensory symptoms consist of numbness in the corner of the mouth. Oro-
pharyngo-laryngeal symptoms are unilateral sensory-motor symptoms of numbness or
paraesthesias (tingling, prickling or freezing) inside the mouth, associated with strange sounds,
such as death rattle, gargling, grunting and guttural sounds.