title: Influence of corpus callosum damage on cognition and physical disability in multiple sclerosis: a multimodal study.
abstract: BACKGROUND
  Corpus callosum (CC) is a common target for multiple sclerosis (MS) pathology. We investigated the influence of CC damage on physical disability and cognitive dysfunction using a multimodal approach.
  
  
  METHODS
  Twenty-one relapsing-remitting MS patients and 13 healthy controls underwent structural MRI and diffusion tensor of the CC (fractional anisotropy; mean diffusivity, MD; radial diffusivity, RD; axial diffusivity). Interhemisferic transfer of motor inhibition was assessed by recording the ipsilateral silent period (iSP) to transcranial magnetic stimulation. We evaluated cognitive function using the Brief Repeatable Battery and physical disability using the Expanded Disability Status Scale (EDSS) and the MS Functional Composite (MSFC) z-score.
  
  
  RESULTS
  The iSP latency correlated with physical disability scores (r ranged from 0.596 to 0.657, P values from 0.004 to 0.001), and with results of visual memory (r = -0.645, P = 0.002), processing speed (r = -0.51, P = 0.018) and executive cognitive domain tests (r = -0.452, P = 0.039). The area of the rostrum correlated with the EDSS (r = -0.442, P = 0.045). MD and RD correlated with cognitive performance, mainly with results of visual and verbal memory tests (r ranged from -0.446 to -0.546, P values from 0.048 to 0.011). The iSP latency correlated with CC area (r = -0.345, P = 0.049), volume (r = -0.401, P = 0.002), MD (r = 0.404, P = 0.002) and RD (r = 0.415, P = 0.016).
  
  
  CONCLUSIONS
  We found evidence for structural and microstructural CC abnormalities associated with impairment of motor callosal inhibitory conduction in MS. CC damage may contribute to cognitive dysfunction and in less extent to physical disability likely through a disconnection mechanism.
authors.affiliation: Center for Neuroimmunology, Service of Neurology, Hospital Clinic and Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: Llufriu
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Blanco
authors.forename: Eloy
authors.initials: E
authors.lastname: Martinez-Heras
authors.forename: Jordi
authors.initials: J
authors.lastname: Casanova-Molla
authors.forename: Iñigo
authors.initials: I
authors.lastname: Gabilondo
authors.forename: Maria
authors.initials: M
authors.lastname: Sepulveda
authors.forename: Carles
authors.initials: C
authors.lastname: Falcon
authors.forename: Joan
authors.initials: J
authors.lastname: Berenguer
authors.forename: Nuria
authors.initials: N
authors.lastname: Bargallo
authors.forename: Pablo
authors.initials: P
authors.lastname: Villoslada
authors.forename: Francesc
authors.initials: F
authors.lastname: Graus
authors.forename: Josep
authors.initials: J
authors.lastname: Valls-Sole
authors.forename: Albert
authors.initials: A
authors.lastname: Saiz
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D003071:Cognition; D003072:Cognition Disorders / Q000209:etiology / Q000473:pathology; D003337:Corpus Callosum / Q000473:pathology* / Q000503:physiopathology; D004185:Disability Evaluation; D055724:Electrophysiological Phenomena; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D020529:Multiple Sclerosis, Relapsing-Remitting / Q000150:complications / Q000473:pathology* / Q000503:physiopathology / Q000523:psychology*; D011446:Prospective Studies