180\u2005Cognitive diagnostic criteria lead to distinct patterns of functional connectivity in secondary progressive MS

Abstract

Resting state functional MRI(rsfMRI) is an established tool for investigating cognitive impairment(CI) (affecting 40–70% dependent on criteria) in Multiple Sclerosis(MS). This study used rsfMRI to investigate the pattern of functional connectivity (FC) in cognitively impaired(CI) and cognitively preserved(CP) secondary progressive MS(SPMS) patients based on criteria. 70 SPMS subjects (age54±7.1, disease duration 22±9.1 years, EDSS 6.0 (range 4.0–6.5), progression duration8.03±5.2 years) were recruited locally. Cognition was assessed by a battery of neuropsychometric tests and defined using the conservative criteria (z-score of -1.96 standard deviations (SD) on ≥2 tests) and lenient criteria (z-score of -1.5SDs on ≥2 tests). RsfMRI obtained using a 3T Philips scanner was pre-processed and underwent Independent Component Analysis(ICA) to identify the Resting State Networks(RSNs). Dual regression compared group-specific maps(i.e. CI vs CP according to criteria). We found that the proportion of SPMS-CI changes by 17.1% when using the more stringent conservative(30%) versus the lenient(47.1%) criteria. Overall, 14 RSNs were identified. The greatest FC differences between CI and CP patients within RSNs occurred with the conservative criteria. Independent of the CI criteria used, the left ventral attention network(LVAN), involved in attention processing, is overall the most impaired network in SPMS-CI suggesting that pathological changes in this RSN may underpin global cognitive problems in SPMS.