title: One declarative memory system or two? The relationship between episodic and semantic memory in children with temporal lobe epilepsy.
abstract: OBJECTIVE
  This study explored verbal semantic and episodic memory in children with unilateral temporal lobe epilepsy to determine whether they had impairments in both or only 1 aspect of memory, and to examine relations between performance in the 2 domains.
  
  
  METHODS
  Sixty-six children and adolescents (37 with seizures of left temporal lobe onset, 29 with right-sided onset) were given 4 tasks assessing different aspects of semantic memory (picture naming, fluency, knowledge of facts, knowledge of word meanings) and 2 episodic memory tasks (story recall, word list recall).
  
  
  RESULTS
  High rates of impairments were observed across tasks, and no differences were found related to the laterality of the seizures. Individual patient analyses showed that there was a double dissociation between the 2 aspects of memory in that some children were impaired on episodic but not semantic memory, whereas others showed intact episodic but impaired semantic memory.
  
  
  CONCLUSIONS
  This double dissociation suggests that these 2 memory systems may develop independently in the context of temporal lobe pathology, perhaps related to differential effects of dysfunction in the lateral and mesial temporal lobe structures.
authors.affiliation: Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada. marylou.smith@utoronto.ca
authors.forename: Mary Lou
authors.initials: ML
authors.lastname: Smith
authors.forename: Suncica
authors.initials: S
authors.lastname: Lah
mesh_terms: D000293:Adolescent; D002648:Child; D004833:Epilepsy, Temporal Lobe / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D007839:Functional Laterality; D006801:Humans; D008568:Memory / Q000145:classification; D008569:Memory Disorders / Q000145:classification* / Q000150:complications / Q000473:pathology; D061212:Memory, Episodic; D011939:Mental Recall; D025341:Principal Component Analysis; D012660:Semantics; D013702:Temporal Lobe / Q000473:pathology / Q000503:physiopathology*; D014706:Verbal Learning