title: Reorganization in cognitive networks with progression of multiple sclerosis: insights from fMRI.
abstract: OBJECTIVE
  Cognitive dysfunction (CD) is frequent in multiple sclerosis (MS) and can occur at early stages. Whereas functional reorganization with disease progression has been described for the motor system in MS using fMRI, no such studies exist for cognition. We attempted to assess the concept of functional reorganization concerning cognition using a simple "Go/No-go" fMRI paradigm.
  
  
  METHODS
  Patients with a clinically isolated syndrome (CIS, n = 10), relapsing-remitting MS (RRMS) (n = 10), or secondary progressive MS (SPMS) (n = 10), and 28 healthy controls (HC), underwent a comprehensive neuropsychological test battery, clinical examination, structural imaging, and an fMRI Go/No-go discrimination task at 3 T.
  
  
  RESULTS
  Patients performed worse than HC regarding memory, sustained attention and concentration, and information processing. These differences were driven by patients with SPMS. The fMRI task elicited activation in a widespread network including bilateral mesial and dorsolateral frontal, parietal, insular, basal ganglia, and cerebellar regions. Task performance was similar between phenotypes, but deviation from the activation pattern observed in HC and patients with CIS increased with disease progression. Patients with RRMS showed increased brain activation in the precuneus, both superior parietal lobes, and the right fusiform gyrus, and recruited the hippocampus with increasing demands. Patients with SPMS demonstrated the most abnormal network function, including recruitment of pre-SMA, bilateral superior and inferior parietal, dorsolateral prefrontal, right precentral, bilateral postcentral, and right temporal brain areas.
  
  
  CONCLUSIONS
  Using a cognitive fMRI paradigm, we were able to confirm adaptive changes of neuronal activation with progressing MS and to provide strong evidence for their compensatory nature, at least partially.
authors.affiliation: Department of Neurology, Medical University of Graz, Auenbruggerplatz 22, A-8036 Graz, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Loitfelder
authors.forename: F
authors.initials: F
authors.lastname: Fazekas
authors.forename: K
authors.initials: K
authors.lastname: Petrovic
authors.forename: S
authors.initials: S
authors.lastname: Fuchs
authors.forename: S
authors.initials: S
authors.lastname: Ropele
authors.forename: M
authors.initials: M
authors.lastname: Wallner-Blazek
authors.forename: M
authors.initials: M
authors.lastname: Jehna
authors.forename: E
authors.initials: E
authors.lastname: Aspeck
authors.forename: M
authors.initials: M
authors.lastname: Khalil
authors.forename: R
authors.initials: R
authors.lastname: Schmidt
authors.forename: C
authors.initials: C
authors.lastname: Neuper
authors.forename: C
authors.initials: C
authors.lastname: Enzinger
mesh_terms: D000328:Adult; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping / Q000379:methods; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology; D009415:Nerve Net / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D055815:Young Adult