Cognitive Impairment in Multiple Sclerosis - Recent Advances and Future Prospects

Multiple sclerosis (MS) is characterised not only by physical disability but also by gradual cognitive impairment. A large proportion of patients exhibit signs of cognitive deficit that negatively affect their quality of life. Reduced processing speed is often seen with the disease and several tests have been developed to measure its severity, including the Paced Auditory Serial Addition Test (PASAT) and the Symbol Digit Modality Test (SDMT). Long-term memory function is also commonly impaired in MS and studies suggest problems in primary registration of information. Also affected are executive functions used in novel planning and problem-solving. To evaluate cognitive function, cognitive test batteries with varying effectiveness have been introduced. The correlation of cognitive performance with magnetic resonance imaging (MRI) results remains inconsistent as multiple pathologies lead to the observed impairments. Therefore, combinations of MRI data are most successful at predicting deficiencies. The efficacy of current MS treatments in terms of cognition is unclear, making their clinical evaluation a great unmet need; the same is true of universal, validated cognitive measures that can be easily administered to MS patients around the world.