Two Year Progression of Working Memory Impairments In Early Relapsing-Remitting Multiple Sclerosis: Appraisal of Working Memory Profiles And Measurement Sensitivity
Abstract Working memory (WMem) impairments are a devastating symptom of Multiple Sclerosis (MS) that manifest as distinct profiles depending upon the type of impairment. It is unknown what WMem impairment profiles occur in early MS and how best to diagnose and measure their progression.88 participants (63 early relapsing-remitting MS, 25 healthy controls) were reviewed annually for two years (baseline, +1 year, +2 years) and completed five WMem tasks: oculomotor (OM) n-back-visual spatial sketchpad; digit-span forwards-phonological loop; California Verbal Learning Test (CVLT)-episodic buffer; digit-span backwards- central executive; symbol digit modalities test (SDMT)-cognitive processing speed. 65% of RRMS patients exhibited visual-spatial WMem impairments followed by 32% for episodic, 30% phonological loop, 24% central executive, 11% cognitive processing speed. These manifested alone (51%) or in combination (48%), with combined impairments the best marker of general WMem impairment. Significant progression in visual-spatial impairments was found for 24% of RRMS patients, with the OM n-back maintaining sensitivity to general WMem impairment and progression. No other WMem subcomponent progressed or task maintained sensitivity. The results of this study provides crucial knowledge for the creation of interventions to treat WMem impairment in early RRMS, providing key targets for treatment and endpoints for determining efficacy.