The Verbal IQ/Performance IQ discrepancy as a sign of seizure focus laterality in pediatric patients with epilepsy

A large Verbal IQ (VIQ)/Performance IQ (PIQ) discrepancy has been viewed as a sign of lateralized brain dysfunction. The current study was conducted to determine if the presence of a large VIQ/PIQ discrepancy (≥15 points) would accurately predict laterality of seizure foci in pediatric patients with epilepsy. A discrepancy score (VIQ - PIQ) was calculated for 130 children (mean age = 12.25) undergoing presurgical epilepsy evaluations. Patients were grouped on the basis of language mediation confirmed through the intracarotid amobarbital procedure. Large discrepancies were noted in 34% of the group with typical language and 24% of the children with atypical language organization. When present, this discrepancy accurately lateralized seizure focus for 79% of those with typical and 57% of those with atypical language organization. The presence of the discrepancy was unrelated to seizure control following surgery for the atypical language group. In the typical language group, 85% of children with discrepancies, but only 63% of children without discrepancies, achieved seizure control. Results suggest that the presence of a large discrepancy is not effective, by itself, in lateralizing seizure foci, but may contribute to refining predictions of surgical outcome.