Page 91 - ILAE_Lectures_2015

Brief 1–3 second generalised bursts of 3–5 Hz slow waves with intermixed small spikes without
associated overt clinical symptoms may occur in about 4% of patients with rolandic epilepsy2,36.
Typical 3 Hz spike-wave discharges and absence seizures are rare2,36,37, though a high incidence
of them has been reported38.

CTS are diagnostic markers of benign rolandic epilepsy only in a suggestive clinical
presentation. Their frequency, location and persistence do not determine the clinical
manifestations, severity and frequency of seizures or the prognosis. It is well established that
CTS are not specific to rolandic epilepsy2,39 as they:

 occur in 2–3% of normal school-aged children, of whom less than 10% develop
rolandic seizures40-43

 are common among relatives of children with rolandic epilepsy44,45
 may occur in a variety of organic brain diseases with or without seizures, such as

cerebral tumours, Rett syndrome, fragile X syndrome and focal cortical dysplasia2,39
 may incidentally be found in non-epileptic children with various symptoms, such as

headache, speech, and behavioural and learning difficulties40.

Somatosensory stimulation is common form of activation of CTS (10–20%)2,46-49 and evokes
GSES, which correspond to mid- or long-latency somatosensory evoked potentials50. GSES,
like spontaneous CTS, occur in children with or without seizures and disappear with age.

There have been around 20 reported ictal EEGs of rolandic seizures showing an initial paucity
of spontaneous CTS before the onset of the ictal discharge, which appears contralateral to the
clinical manifestations in the rolandic regions and consists of slow waves intermixed with
spikes2,10,51. GTCS, when they occurred, were preceded by focal clinical and EEG features2,10,28.

Aetiology
Rolandic epilepsy is genetically determined although conventional genetic influences may be
less important than other mechanisms52,53. There is evidence of linkage with chromosome
15q1454. Autosomal dominant inheritance with age-dependent penetrance refers to the EEG
CTS and not to the clinical syndrome of rolandic epilepsy44,45. Siblings or parents of patients
with rolandic epilepsy may rarely have the same type of seizures or other phenotypes of BCSSS,
such as PS. Reported occurrence of febrile seizures ranges from 10–20%55.

Pathophysiology
As indicated by the distribution of centrotemporal spikes, the epileptogenic zone in rolandic
epilepsy involves neuronal networks within the rolandic cortex surrounding the central fissure
bilaterally. This is congruent with the seizure symptomalogy (symptomatogenic zone) and in
agreement with those described by Penfield and Rasmussen56 during electrical stimulation of
the lower part of the precentral and postcentral gyrus in man.

The speech arrest is due to anarthria attributed to loss of the power and co-ordination of the
musculature responsible for the articulation of words. There is no impairment of the cortical
language networks. Hypersalivation most probably relates to the involvement of the superior
bank of the sylvian fissure57, but defining ictal symptomatogenesis by plotting the simple
topographic co-ordinates of an ictal discharge can hardly explain the high prevalence of
hypersalivation in benign rolandic epilepsy compared to its exceptional only occurrence in
adults with symptomatic foci of similar topography. Nor can it explain the opercular status
epilepticus, with the speech arrest lasting several hours, drooling and bilateral regional
twitching that is associated with diffuse or bilateral rolandic spike-wave activity, but does not
propagate in a conventional way and does not involve other systems like, for instance, the motor
strip or the language function. Therefore, at variance with the symptomatic adult focal
epilepsies of comparable but more discretely localised topography, rolandic epilepsy reflects