title: Low prevalence but high specificity of material-specific memory impairment in epilepsy associated with hippocampal sclerosis.
abstract: OBJECTIVE
  Material-specific memory impairment is used as a lateralizing tool in the evaluation of temporal lobe epilepsy. Lateralizing ability of material-specific memory deficits in temporal lobe epilepsy remains controversial.
  
  
  METHODS
  We studied memory impairment profiles of verbal and nonverbal memory deficits with eight memory subtests of four neuropsychological instruments (two verbal and two nonverbal) in 87 right-handed patients with epilepsy associated with unilateral mesial temporal sclerosis (MTS; 44 right - R, 43 left - L) and 42 controls, with an IQ >70, at least 8 years of education, and without comorbidities.
  
  
  RESULTS
  Selective verbal memory impairment was noted in 11 of 43 or 25.6% of left MTS cases, with 82.2% specificity, whereas selective nonverbal memory impairment was noted in 11 of 42 or 26.2% of right MTS cases, with 92% specificity. Nonlateralizing profiles of memory performance were seen in the remaining 65 of 87 patients. Approximately half (46/87 or 52.9%) of the patients had intact memory function in both modalities, equally distributed between patients with right MTS (23/44) and left MTS (23/43). Global impairment of both memory types was seen in 12 of 87 or 13.8% of patients, equally distributed between the two groups (7/43 left and 5/44 right).
  
  
  CONCLUSIONS
  Lateralizing profiles of selective verbal and nonverbal memory deficits are highly specific for left and right MTS, although infrequently encountered in our patients. Nonlateralizing profiles predominated in this population. These findings suggest hemispheric asymmetry memory function, with complex functional interaction of the hippocampi, and possible compensatory mechanisms in the setting of a unilateral lesion.
authors: Department of Neurology, São Paulo University Medical School, São Paulo, Brazil.
authors: Luiz H
authors: LH
authors: Castro
authors: Liliane C A M
authors: LC
authors: Silva
authors: Carla C
authors: CC
authors: Adda
authors: Natalie H C
authors: NH
authors: Banaskiwitz
authors: Alana B
authors: AB
authors: Xavier
authors: Carmen L
authors: CL
authors: Jorge
authors: Rosa M
authors: RM
authors: Valerio
authors: Ricardo
authors: R
authors: Nitrini
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D004833:Epilepsy, Temporal Lobe / Q000150:complications* / Q000473:pathology; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000453:epidemiology / Q000209:etiology* / Q000473:pathology; D008875:Middle Aged; D009483:Neuropsychological Tests; D015995:Prevalence; D012598:Sclerosis; D055815:Young Adult
keywords: Cognition; Memory; Mesial temporal sclerosis; Neuropsychology; Temporal lobe epilepsy