Marieke van Rosmalen

Chapter 2 26 ABSTRACT Objective: To assess the clinical course of multifocal motor neuropathy (MMN) in a large cohort of patients and to identify predictive factors of a progressive disease course. Methods: Between May 2015 and February 2016, we collected clinical data from 100 patients with MMN of whom 60 had participated in a nationwide cross-sectional cohort study in 2007. We documented clinical characteristics using standardized questionnaires and performed a standardized neurological examination. We used multiple linear regression analysis to identify factors that correlated with worse outcome. Results: We found that age of diagnosis (45.2 vs. 48.6 years, p < 0.02) significantly increased between 2007 and 2015 – 2016, whereas diagnostic delay decreased with 15 months. Seven out of ten outcome measures deteriorated over time (all p < 0.01). Patients who had a lower Medical Research Council (MRC) sum score and absence of one or more reflexes at the baseline visit showed a greater functional loss at follow up ( p = 0.007 and p = 0.016). Conclusion: Our study shows that MMN is a progressive disease. Although 87% of patients received maintenance treatment, muscle strength, reflexes, vibration sense, and the Self-Evaluation Scale significantly deteriorated over time. Lower MRC sum score and absence of reflexes predicted a more progressive disease course.