title: The influence of seizure frequency on anterograde and remote memory in mesial temporal lobe epilepsy.
abstract: OBJECTIVE
  Seizure frequency, although considered as an important factor in memory impairment in mesial temporal epilepsy (mTLE), is mostly confounded with other clinical variables, making it unclear to what extent recurrent seizures actually interfere with memory. The present study focuses on the influence of seizure frequency, studied as a main variable, on anterograde and remote memory.
  
  
  METHODS
  Seventy-one patients with unilateral mTLE were divided into two subgroups, as a function of their seizure frequency (monthly versus weekly seizures). Other seizure-related variables were controlled, namely, lateralisation and type of lesion, age at onset, years of ongoing seizures, etiologic factors, and number of AED. A comprehensive neuropsychological examination, including anterograde memory (verbal and non verbal recognition memory and free recall) tasks together with a large range of tests exploring different domains of remote memory, was carried out.
  
  
  RESULTS
  Despite similar results on IQ, executive functions and attention, the low seizure-frequency group performed significantly better than the high seizure-frequency group on anterograde memory tests. Loss of autobiographical episodes and public-events memory, concomitant with spared personal semantic knowledge, was observed in both patient groups compared with healthy subjects. A worsening effect of high seizure frequency was recorded for autobiographical incidents and news-events memory, but unexpectedly, not for memory for famous people.
  
  
  CONCLUSIONS
  The study of seizure frequency as the main variable leads us to suggest that high seizure frequency, itself, potentiates the effects of mesial temporal lobe damage on episodic memory deficits.
authors.affiliation: Octogone - CERPP, EA 4156, University Toulouse II - Le Mirail, Toulouse, France. Electronic address: voltzenl@univ-tlse2.fr.
authors.forename: Virginie
authors.initials: V
authors.lastname: Voltzenlogel
authors.affiliation: Department of Neurology, Central Hospital, Nancy, France. Electronic address: jp.vignal@chu-nancy.fr.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Vignal
authors.affiliation: Department of Neurology, University Hospital, Strasbourg, France. Electronic address: Edouard.Hirsch@chru-strasbourg.fr.
authors.forename: Edouard
authors.initials: E
authors.lastname: Hirsch
authors.affiliation: INSERM, U1114 and Strasbourg University, Strasbourg, France. Electronic address: manning@unistra.fr.
authors.forename: Liliann
authors.initials: L
authors.lastname: Manning
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D003072:Cognition Disorders / Q000209:etiology; D004833:Epilepsy, Temporal Lobe / Q000150:complications*; D005260:Female; D006801:Humans; D007360:Intelligence; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology*; D057567:Memory, Long-Term / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests; D012640:Seizures / Q000503:physiopathology*; D014706:Verbal Learning
keywords: Anterograde memory; Autobiographical memory; Cognition; Mesial temporal lobe epilepsy; Public-events memory; Seizure frequency