Clinical and electroencephalographic features of infantile spasms associated with malformations of cortical development

The aim of this study was to reveal the clinical and encephalographic (EEG) features of infantile spasms (IS) with malformations of cortical development (MCDs). The clinical features, EEG findings, neuroimaging studies and outcomes of various therapeutic modalities for 27 patients with IS and MCDs were reviewed. Background activities of EEG on the MCDs, i.e. asymmetric hypsarrhythmia, localized persistent polymorphic slowing, asymmetric slowing and diffuse fast activities, were shown in 22, 15, 9 and 2 patients, respectively. Partial epileptiform discharges such as localized paroxysmal fast activities, spindle-shaped fast activities and subclinical seizures were shown in 15, 8 and 10 patients, respectively, and the lateralized prominence of generalized paroxysmal fast activities and generalized sharp and wave discharges in 4 and 5 patients, respectively. MCDs were suspected in 5 patients, as revealed by EEG and/or functional neuroimagings without distinct magnetic resonance imaging lesions, and confirmed by pathologic findings. Of the 11 patients treated with surgical resection, 8 became seizure free. EEG features can be very useful in the identification of underlying cortical dysgenesis in patients with IS. However, in one patient who underwent epilepsy surgery in early infancy, we observed easy bleeding and difficult hemostasis from friable vascular and parenchymal tissues. Various EEG features can be very useful in screening underlying MCDs. In addition, epilepsy surgery can be an effective therapeutic modality in many patients with otherwise medically intractable IS with MCDs. However, surgical intervention in extremely young infants should be performed with caution.