title: Structural and functional surrogates of cognitive impairment at the very early stage of multiple sclerosis.
abstract: Following our previous reports based on parametric MRI methods (T(2)-weighted MRI, statistical mapping analysis of magnetization transfer ratio images and functional MRI) applied to a population of 18 patients with clinically isolated syndrome suggestive of multiple sclerosis, we have reviewed the possible structural and functional surrogates of MS that could explain the subtle cognitive impairment related to attention and working memory deficits evaluated with paced auditory serial addition test (PASAT). We propose that the brain substrates underlying cognitive impairment observed at the very early stage of MS are multifactorial. Several components could influence PASAT performances in patients: i) the extent of diffuse white matter damage, ii) the location of visible and non visible lesions, iii) the connectivity efficiency between distant brain functional areas involved in working memory processes and iv) the cortical reorganization. Nevertheless, individually, each of these parameters may have few influences on PASAT performance in patients. Using a multiregression model built with independent MR parameters, a very good evaluation of PASAT scores has been obtained in this limited number of patients explaining 90% of the variance. In conclusion, the different aspects of tissue and functional pathological brain underpinnings must be accounted to monitor accurately new therapeutic strategies for the treatment of early cognitive deficits related to MS.
authors.affiliation: Centre de Résonance Magnétique Biologique et Médicale, CRMBM UMR CNRS 6612, Faculté de Médecine, 27 Boulevard Jean Moulin 13385 Marseilles cedex 05, France. jp.ranjeva@medecine.univ-mrs.fr
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Ranjeva
authors.forename: Bertrand
authors.initials: B
authors.lastname: Audoin
authors.forename: My Van
authors.initials: MV
authors.lastname: Au Duong
authors.forename: Sylviane
authors.initials: S
authors.lastname: Confort-Gouny
authors.forename: Irina
authors.initials: I
authors.lastname: Malikova
authors.forename: Patrick
authors.initials: P
authors.lastname: Viout
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Soulier
authors.forename: Jean
authors.initials: J
authors.lastname: Pelletier
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Cozzone
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D003072:Cognition Disorders / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D009103:Multiple Sclerosis / Q000150:complications / Q000503:physiopathology*