Functional and structural MRI correlates of executive functions in multiple sclerosis
Olga Marchesi, Raffaello Bonacchi, Paola Valsasina, Paolo Preziosa, Elisabetta Pagani, Laura Cacciaguerra, Alessandro Meani, Lorenzo Conti, Damiano Mistri, Maria A. Rocca, Massimo Filippi
Abstract
Background: Executive dysfunctions, including difficulties in attention, working memory, planning, and inhibition affect 15%–28% of multiple sclerosis (MS) patients. Objectives: To investigate structural and functional magnetic resonance imaging (MRI) abnormalities underlying executive function (EF) in MS patients. Methods: A total 116 MS patients and 65 controls underwent resting-state (RS) and diffusion-weighted sequences and neuropsychological examination, including Wisconsin Card Sorting Test (WCST) to test EF. Brain RS cognitive networks and fractional anisotropy (FA) from a priori selected white matter tracts were derived. Associations of WCST scores with RS functional connectivity (FC) and FA abnormalities were investigated. Results: In MS patients, predictors of working memory/updating were: lower corpus callosum (CC) FA, lower left working-memory network (WMN), right WMN RS FC for worse performance; lower executive control network (ECN), higher default-mode network (DMN), and salience network (SN) RS FC for better performance ( R 2 = 0.35). Predictors of attention were lower CC genu FA, lower left WMN, and DMN RS FC for worse performance; higher left WMN and ECN RS FC for better performance ( R 2 = 0.24). Predictors of worse shifting/inhibition were lower CC genu and superior cerebellar peduncle (SCP) FA, lower left WMN RS FC for worse performance; and higher ECN RS FC for better performance ( R 2 = 0.24). Conclusions: CC and SCP microstructural damage and RS FC abnormalities in cognitive networks underlie EF frailty in MS.