Influence of Corpus Callosum Damage on Cognition and Physical Disability in Multiple Sclerosis: A Multimodal Study

Abstract

BackgroundCorpus 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.MethodsTwenty-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.ResultsThe 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).ConclusionsWe 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.

Postnatal Iron Deficiency Alters Brain Development in Piglets

“…ID reduced fractional anisotropy in the corpus callosum, the largest white matter structure in the brain, which may contribute to impaired interhemispheric communication. Importantly, impairment of the corpus callosum microstructure correlates with decreased cognitive function (26). Although the thalamus and hippocampi of ID piglets did not significantly differ from CON piglets in terms of fractional anisotropy, radial diffusivity, a measure of the minor diffusion eigenvectors, was greater in ID piglet hippocampi.…”

Combined structural and functional patterns discriminating upper limb motor disability in multiple sclerosis using multivariate approaches

“…Asterisks denoted the significance of the level of accuracy with ** for p < 0.01 and *** for p < 0.001 structure providing interhemispheric communication between grey matter structures, can be profoundly damaged in MS (Evangelou et al 2000;Gean-Marton et al 1991) even when the T2 lesions only consisted around 1.4 % of the callosal volume (Ozturk et al 2010). Damage in the corpus callosum has been previously linked to both weakened interhemispheric FCs (Zito et al 2014) and physical disability (Audoin et al 2007;Llufriu et al 2012;Ozturk et al 2010;Yaldizli et al 2011). In addition, white matter lesions within the hemispheres affecting any fibres connected with the corpus callosum may also influence the functional connectivity.…”

Corpus Callosum Atrophy Correlates with Gray Matter Atrophy in Patients with Multiple Sclerosis

“…Prior studies have associated corpus callosum atrophy with the level of disability in MS. 9, 10 Furthermore, the corpus callosum is implicated in cognitive dysfunction in MS and its involvement may disrupt inter-hemispheric connectivity. 11,12,13,14,15,16 The relationship between corpus callosum damage and cognitive dysfunction can be shown even in benign MS. 17 …”