title: Cognitive reserve and cortical atrophy in multiple sclerosis: a longitudinal study.
abstract: OBJECTIVE
  To test the cognitive reserve (CR) hypothesis in the model of multiple sclerosis (MS) by assessing the interactions among CR, brain atrophy, and cognitive efficiency in patients with relapsing-remitting MS.
  
  
  METHODS
  A Cognitive Reserve Index was calculated including education, premorbid leisure activities, and IQ. Brain atrophy was assessed through magnetic resonance quantitative parameters of normalized total brain volume and normalized cortical volume. Cognitive function was measured using Rao's Brief Repeatable Battery.
  
  
  RESULTS
  Fifty-two patients with relapsing-remitting MS were evaluated at baseline and 35 of them were reassessed after a 1.6-year follow-up period. At baseline, higher CR predicted better performance on most of the Brief Repeatable Battery tests, independent of brain atrophy and clinical and demographic characteristics (p ≤ 0.021). An interaction between CRI and normalized cortical volume predicted better cognitive performance on tasks of verbal memory and attention/information processing speed (p < 0.005). However, at the follow-up examination, progressing cortical atrophy (β = 0.45; p = 0.008) and older age (β = -0.33; p = 0.044) were the only predictors of deteriorating cognitive performance.
  
  
  CONCLUSIONS
  Our findings suggest that higher CR in individuals with MS may mediate between cognitive performance and brain pathology. CR-related compensation may, however, fail with progression of damage. The time window of opportunity for therapeutic approaches aimed at intellectual enhancement most likely lies in the earliest disease stages.
authors.affiliation: Department of Neurology, University of Florence, Italy. mariapia.amato@unifi.it
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Amato
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Razzolini
authors.forename: Benedetta
authors.initials: B
authors.lastname: Goretti
authors.forename: Maria Laura
authors.initials: ML
authors.lastname: Stromillo
authors.forename: Francesca
authors.initials: F
authors.lastname: Rossi
authors.forename: Antonio
authors.initials: A
authors.lastname: Giorgio
authors.forename: Bahia
authors.initials: B
authors.lastname: Hakiki
authors.forename: Marta
authors.initials: M
authors.lastname: Giannini
authors.forename: Luisa
authors.initials: L
authors.lastname: Pastò
authors.forename: Emilio
authors.initials: E
authors.lastname: Portaccio
authors.forename: Nicola
authors.initials: N
authors.lastname: De Stefano
mesh_terms: D000328:Adult; D001284:Atrophy; D002540:Cerebral Cortex / Q000473:pathology*; D058245:Cognitive Reserve; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology*; D009483:Neuropsychological Tests