Mind the Gap: Improving the Identification of Cognitive Impairment in Multiple Sclerosis

In this thesis, we aimed to improve the identification of cognitive impairment in people with multiple sclerosis (PwMS). In chapter 2, we investigated several challenges associated with cognitive assessment in MS. We found that slowed information processing speed (IPS) in PwMS was associated with specific aspects of visuospatial memory performance, indicating that reduced memory performance may partly reflect slowed IPS rather than a primary memory impairment. We also examined cognitive awareness in PwMS and found that 54% of participants overestimated their cognitive performance before neuropsychological assessment (NPA). After NPA, estimations generally became more accurate, although underestimation became relatively more common. Objective cognitive performance was the strongest predictor of cognitive awareness: PwMS with lower cognitive performance more often overestimated their cognitive functioning, whereas those with higher performance were more likely to underestimate themselves. We further discussed several limitations of current NPA in MS, including its time-intensive nature, reliance on specialized personnel, burden for PwMS, and the influence of fatigue, mood symptoms, and visual or motor impairments on test performance. In chapter 3, we investigated the Multiple Screener©, a fully self-administered digital cognitive screening instrument. In a multicenter study across 12 hospitals, the Multiple Screener© showed 69.6% sensitivity and 76.6% specificity for differentiating cognitively impaired and cognitively preserved PwMS, with comparable results in an independent replication cohort. The screener was less accurate in distinguishing mild cognitive impairment and demonstrated moderate to good test-retest reliability. The screener should not replace comprehensive NPA but may serve as a triage tool to support more systematic monitoring and targeted referral. Finally, in chapter 4, we qualitatively investigated how PwMS experience NPA and discussions about cognition with their healthcare professional. Cognition was not routinely discussed during consultations and was often only addressed once cognitive problems affected daily life. Experiences with NPA and preferences regarding regular cognitive monitoring varied between PwMS. Healthcare professionals recognized these experiences and highlighted the potential value of brief digital tools, pre-consultation questionnaires, and greater knowledge of cognitive symptoms and available interventions for routine cognitive assessment. Combined, the findings of this thesis show that integrating objective cognitive assessment with self-report and individual preferences, supported by accessible digital screening, may contribute to earlier and more systematic identification of cognitive impairment in MS.