Assessment and surgical outcomes for mild type i and severe type II cortical dysplasia: A critical review and the UCLA experience

Jason T. Lerner, Noriko Salamon, Jason S. Hauptman, Tonicarlo R. Velasco, Marta Hemb, Joyce Y. Wu, Raman Sankar, W. Donald Shields, Jerome Engel, Itzhak Fried, Carlos Cepeda, Veronique M. Andre, Michael S. Levine, Hajime Miyata, William H. Yong, Harry V. Vinters, Gary W. Mathern

Research output: Contribution to journalReview articlepeer-review


Recent findings on the clinical, electroencephalography (EEG), neuroimaging, and surgical outcomes are reviewed comparing patients with Palmini type I (mild) and type II (severe) cortical dysplasia. Resources include peer-reviewed studies on surgically treated patients and a subanalysis of the 2004 International League Against Epilepsy (ILAE) Survey of Pediatric Epilepsy Surgery. These sources were supplemented with data from University of California, Los Angeles (UCLA). Cortical dysplasia is the most frequent histopathologic substrate in children, and the second most common etiology in adult epilepsy surgery patients. Cortical dysplasia patients present with seizures at an earlier age than other surgically treated etiologies, and 33-50% have nonlocalized scalp EEG and normal magnetic resonance imaging (MRI) scans. 2-(18F)Fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) is positive in 75-90% of cases. After complete resection, 80% of patients are seizure free compared with 20% with incomplete resections. Compared with type I, patients with type II cortical dysplasia present at younger ages, have higher seizure frequencies, and are extratemporal. Type I dysplasia is found more often in adult patients in the temporal lobe and is often MRI negative. These findings identify characteristics of patients with mild and severe cortical dysplasia that define surgically treated epilepsy syndromes. The authors discuss future challenges to identifying and treating medically refractory epilepsy patients with cortical dysplasia.

Original languageEnglish
Pages (from-to)1310-1335
Number of pages26
Issue number6
StatePublished - Jun 2009
Externally publishedYes


  • EEG
  • GABA
  • Glutamate
  • Hippocampal sclerosis
  • Intracranial electrodes
  • MRI
  • Malformations of cortical development
  • NMDA
  • Review
  • Seizure


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