Clinical outcomes in multifocal motor neuropathy: A combined cross-sectional and follow-up study

Neurology. 2020 Oct 6;95(14):e1979-e1987. doi: 10.1212/WNL.0000000000010538. Epub 2020 Jul 30.


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 neurologic examination. We used multiple linear regression analysis to identify factors that correlated with worse outcome.

Results: We found that age at diagnosis (45.2 vs 48.6 years, p < 0.02) was significantly increased between 2007 and 2015-2016, whereas diagnostic delay decreased by 15 months. Seven out of 10 outcome measures deteriorated over time (all p < 0.01). Patients who had a lower Medical Research Council (MRC) sumscore and absence of 1 or more reflexes at the baseline visit showed a greater functional loss at follow-up (p = 0.007 and p = 0.016).

Conclusions: 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 score significantly deteriorated over time. Lower MRC sumscore and absence of reflexes predicted a more progressive disease course.

Classification of evidence: This study provides Class II evidence that lower MRC sumscore and the absence of reflexes predict a more progressive disease course in patients with MMN.

MeSH terms

  • Adult
  • Aged
  • Cohort Studies
  • Cross-Sectional Studies
  • Disease Progression
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Motor Neuron Disease / physiopathology*
  • Polyneuropathies / physiopathology*