ICTAL CEREBRAL PERFUSION RELATED TO EEG IN DRUG-RESISTANT FOCAL EPILEPSY OF CHILDHOOD

Objectives - To evaluate the EEG changes during seizures in children w ith drug resistant focal epilepsy who demonstrate hypoperfusion at the ''seizure focus'' interictally, but no perfusion change during the se izure. Methods - Ictal EEG findings of six children with focal epileps y who demonstrated hypoperfusion on rCBF SPECT after an interictal inj ection of Tc-99(m) HMPAO concordant with the seizure focus, but who di d not demonstrate rCBF change after an ictal injection (group 1) were reviewed. These were contrasted with the EEG data of six children matc hed as closely as possible for age, type of epilepsy, and pathology wh o did show hyperperfusion at the seizure focus on ictal scan when comp ared with the interictal study (group 2). Results - The children in gr oup 1 showed slowing of the EEG at the time of the Tc-99(m) HMPAO inje ction relative to that seen at the onset of the seizure. Those in grou p 2 showed rhythmic activity, or sharp waves, or both on EEG at the ti me of injection. This last change was also seen consistently when the EEG data of a further 13 children who also showed ictal hyperperfusion at the seizure focus were reviewed. Conclusion - Ictal rCBF does not invariably increase at the seizure focus in patients with drug resista nt focal epilepsy.