title: Brain oscillatory EEG event-related desynchronization (ERD) and -sychronization (ERS) responses during an auditory memory task are altered in children with epilepsy.
abstract: OBJECTIVE
  Children with epilepsy are in risk for cognitive impairment, but reliable methods, other than neuropsychological testing, to verify such a decline are few. The purpose of this study was to assess the effect of infrequent seizures on cognitive skills in children with non-symptomatic focal epilepsy taking antiepileptic medication but still having infrequent seizures.
  
  
  METHODS
  EEG (electroencephalogram) brain electric oscillatory responses of the 4-6Hz, 6-8Hz, 8-10Hz and 10-12Hz EEG frequency bands were studied. These responses, assessed by means of the event-related desynchronization (ERD) and synchronization (ERS) method, were recorded in 6 children with epilepsy (mean age 11.3 years) and in 11 control children (mean age 12 years) while they performed an auditory memory task. All subjects also underwent a comprehensive neuropsychological test battery.
  
  
  RESULTS
  The differences in the 4-6Hz ERD/ERS responses between encoding and recognition were smaller in the children with epilepsy as compared to those of the control children. In the 6-8Hz frequency band, the responses of the two groups dissociated most notably in the frontal electrodes. No statistically significant differences in the alpha frequency range (8-12Hz) were observed between the groups.
  
  
  CONCLUSIONS
  Significant alterations in the lower EEG frequency (4-8Hz) ERD/ERS responses in children with epilepsy during auditory memory processing, as compared to age-matched, healthy children may suggest that seizures affect memory and underlying brain processes, indexed also by poorer performance particularly in neuropsychological subtests related to language functions.
authors.affiliation: Cognitive Science Unit, Department of Psychology, University of Helsinki, 00014 Helsinki, Finland. christina.krause@helsinki.fi
authors.forename: Christina M
authors.initials: CM
authors.lastname: Krause
authors.forename: Petra-Ann
authors.initials: PA
authors.lastname: Boman
authors.forename: Lauri
authors.initials: L
authors.lastname: Sillanmäki
authors.forename: Tarja
authors.initials: T
authors.lastname: Varho
authors.forename: Irma E
authors.initials: IE
authors.lastname: Holopainen
mesh_terms: D000161:Acoustic Stimulation; D000927:Anticonvulsants / Q000627:therapeutic use; D001307:Auditory Perception / Q000502:physiology; D001921:Brain / Q000503:physiopathology; D002648:Child; D003344:Cortical Synchronization; D004569:Electroencephalography; D004827:Epilepsy / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory / Q000502:physiology*; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology*
chemical_list: D000927:Anticonvulsants