title: Cognitive correlates of interictal epileptiform discharges in adult patients with epilepsy in China.
abstract: OBJECTIVE
  Learning difficulties or cognitive impairment has been observed in many patients with epilepsy. Evidence from neurophysiologic and functional neuroimaging suggests that epileptic seizures and/or epileptiform activity can be the dominant factors inhibiting specific brain areas. However, most previous studies were focused on cognitive performance in children. In this study, we analyzed a new cohort of adult patients with frequent interictal epileptiform discharges (IEDs).
  
  
  METHODS
  Data from 67 adult patients with epilepsy were reviewed. Electroencephalography (EEG)-video recording and cognitive testing were performed, and the IED index was estimated as a percentage assigned to one of four categories (<1%, 1-10%, 10-50%, and >50%) during either wakefulness or sleep. Correlations of cognitive test results and clinical characteristics of IED categories were analyzed. The effects of the frequency, duration, location, and sleep-wake cycles of IEDs on cognition (intelligence and memory capacity) were analyzed.
  
  
  RESULTS
  Patients with an IED index >10% showed impaired performance on the Chinese Wechsler Adult Intelligence Scale (WAIS-RC) and the Chinese Wechsler Memory Scale (WMS). This effect was detected independently from other IED frequencies and other IED-related variables, such as duration, distribution, and location. The impact of waking or sleeping IEDs was of equal importance in contributing to impaired WAIS-RC and WMS performance.
  
  
  CONCLUSIONS
  An IED frequency of more than 10% in both waking and sleeping EEGs is associated with impaired cognitive performance in adult patients. However, whether patients with a high IED frequency but low seizure frequency will benefit from antiepileptic treatment should be examined in future studies.
authors.affiliation: Department of Neurology, The First Affiliated Hospital of Jilin University, 71 Xinmin Street, Changchun, Jilin, PR China.
authors.forename: Yudan
authors.initials: Y
authors.lastname: Lv
authors.forename: Zan
authors.initials: Z
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Cui
authors.forename: Dihui
authors.initials: D
authors.lastname: Ma
authors.forename: Hongmei
authors.initials: H
authors.lastname: Meng
mesh_terms: D000293:Adolescent; D000328:Adult; D000927:Anticonvulsants / Q000627:therapeutic use; D001921:Brain / Q000473:pathology / Q000503:physiopathology; D058256:Brain Waves / Q000502:physiology*; D002681:China / Q000453:epidemiology; D003072:Cognition Disorders / Q000209:etiology*; D004569:Electroencephalography; D004827:Epilepsy / Q000150:complications* / Q000188:drug therapy / Q000453:epidemiology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012890:Sleep / Q000502:physiology; D013223:Statistics as Topic; D016138:Walking / Q000502:physiology; D055815:Young Adult
chemical_list: D000927:Anticonvulsants
keywords: Cognitive test; Electroencephalography (EEG); Interictal epileptiform discharges; Neurophysiologic test