title: Consistent localization of interictal epileptiform activity on EEGs of patients with tuberous sclerosis complex.
abstract: OBJECTIVE
  We addressed consistent localization of focal interictal epileptiform activity on EEGs of patients with tuberous sclerosis complex (TSC) and epilepsy.
  
  
  METHODS
  Twenty-one patients with TSC with a 10-year history of epilepsy and interictal epileptiform activity in three or more EEG recordings were included. None of the patients had undergone epilepsy surgery. Local maxima of interictal epileptiform activity were measured from 76 EEG traces and 33 EEG reports. Information about the patients' clinical course was extracted from their medical records. Magnetic resonance imaging (MRI) and neuropsychological examinations were performed. Statistical analysis was performed with the Mann-Whitney U test.
  
  
  RESULTS
  In eight patients, interictal epileptiform activity was consistently detected in one or two regions (group 1), and in 13 patients, epileptiform activity was detected in three or more regions (group 2). The number of foci increased throughout the disease course in both groups. Age at seizure onset and IQ were significantly higher in group 1. Complex partial seizures occurred more often in the patients of group 1. In 19 of the 21 patients, the most consistent epileptiform activity was localized in the frontotemporal region.
  
  
  CONCLUSIONS
  Ninety percent of patients with TSC showed at least one region of consistent interictal epileptiform activity. Patients with one or two regions of epileptiform activity were older at seizure onset, often experienced complex partial seizures, and had mild or no mental deficits. These patients may be candidates for epilepsy surgery.
authors.affiliation: Department of Child Neurology, Rudolf Magnus Institute of Neuroscience, University Medical Center, Utrecht, The Netherlands. f.e.jansen@neuro.azu.nl
authors.forename: Floor E
authors.initials: FE
authors.lastname: Jansen
authors.forename: Alexander C
authors.initials: AC
authors.lastname: van Huffelen
authors.forename: Mireille
authors.initials: M
authors.lastname: Bourez-Swart
authors.forename: Onno
authors.initials: O
authors.lastname: van Nieuwenhuizen
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D001931:Brain Mapping / Q000379:methods*; D002540:Cerebral Cortex / Q000503:physiopathology*; D002648:Child; D004569:Electroencephalography / Q000379:methods / Q000706:statistics & numerical data*; D004827:Epilepsy / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011300:Preoperative Care; D012189:Retrospective Studies; D014402:Tuberous Sclerosis / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery