title: Focal, continuous spikes suggest cortical developmental abnormalities. Clinical, MRI and neuropathological correlates.
abstract: OBJECTIVE
  Widespread use of MRI now gives us increased insights into the different expressions of malformations of cortical development (MCD). The heterogeneity of these disorders are reflected by their varied clinical and neuroimaging features. Characteristic and intense scalp EEG abnormalities have been described in some patients.
  
  
  METHODS
  We report the MRI and clinical findings of 3 adult patients (age 32-36) with a peculiar EEG pattern of distinct, localized, fast, continuous spiking. These patients represent all patients with such EEG findings that have been recognized by the first author during 9 years.
  
  
  RESULTS
  MRI showed MCDs in all, respectively hemimegalencephaly, a subcortical heterotopion, and a focal cortical dysgenesis. The EEG findings had been stable since childhood and were posteriorly located. Two patients had fairly well controlled epilepsy in adult age. The third patient was incapacitated by persistent seizures and was treated with surgery. Histologically cortical dysplasia with neuronal clusters was found in this patient. Variable degrees of cognitive dysfunction were present in all.
  
  
  CONCLUSIONS
  Focal, continuous, fast spiking is an unusual scalp EEG pattern. It is not an inevitable sign of severe epilepsy. It may suggest an MCD. It is not yet clear to what extent such findings are predictive of a dysgenetic etiology of epilepsy.
authors.affiliation: Department of Neurology, Trondheim University Hospital, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Brodtkorb
authors.forename: K
authors.initials: K
authors.lastname: Andersen
authors.forename: O
authors.initials: O
authors.lastname: Henriksen
authors.forename: G
authors.initials: G
authors.lastname: Myhr
authors.forename: K
authors.initials: K
authors.lastname: Skullerud
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D002540:Cerebral Cortex / Q000002:abnormalities* / Q000503:physiopathology*; D004569:Electroencephalography; D004827:Epilepsy / Q000503:physiopathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D012640:Seizures / Q000503:physiopathology