Abstracts

RATIONALE: This retrospective study was undertaken to determine (1) if patients having tactile-evoked rolandic discharges behaved differently from those with spontaneously occurring rolandic discharges; (2)whether the presence of tactile-evoked rolandic discharges was a marker for the future development of epilepsy.
METHODS: During this 8 year study 2614 patients (excluding neonates [lt] 2 months CA) presented with epileptiform discharges. Of those, 304 (11.6%) had rolandic discharges (CZ, PZ, C4 or C3). These 304 patients formed two groups - patients with spontaneous rolandic discharges that could not be evoked by tactile stimulation (non-tactile - NT) and patients with spontaneous rolandic discharges that could be enhanced with tactile stimulation (tactile enhanced - TE). Additionally over a 14 month period every patient having an EEG had tactile stimulation of both hands and both feet. At all other times during the study period any patient having spontaneous rolandic discharges on their EEG had both their hands and feet tapped. This consisted of tapping of the palmar tips of the fingers or toes at approximately one-second intervals to produce a small but rapid extension of the distal phalanges.
RESULTS: Tactile-enhanced discharges constituted 38.2%(116/304)of all rolandic discharges, and were seen from 3 months to 15.2 years of age. Discharges seen only with tactile stimulation (tactile only - TO) were found in 3.8%, aged from 2.4 months to 18.9 years.
Patients with TE and TO discharges had a higher incidence of normal development, intelligence and normal neurological exams, and a lower incidence of focal or generalized background EEG abnormalities. The incidence of seizures in patients with normal background and no co-existing epileptiform abnormalities was low in all 3 groups. The question was then raised, were the interictal rolandic discharges the electrographic correlate to the patient[ssquote]s seizure disorder? Of all three goups only one patient in the TE group had partial motor seizures with corresponding contralateral central discharges.
Only two patients who had no seizures at the time of their first EEG (EEG during which either NT, TE or TO discharges were seen) subsequently went on to develop seizures. One patient from the NT group went on to develop Benign Epilepsy of Childhood with centrotemporal discharges after 5 years and one patient in the TO group developed complex partial frontal seizures in association with multifocal rolandic and non-rolandic discharges after 6 years.
CONCLUSIONS: In summary, we hypothesise that tactile-evoked rolandic discharges are a benign age-related phenomenon which do not represent a marker for the future development of epilepsy, and are not the interictal electrographic correlate to an already existing seizure disorder.