Long-term motor stability but increasing non-motor burden in multifocal motor neuropathy: a 6-year real-world follow-up study during the COVID-19 era.

INTRODUCTION

Multifocal motor neuropathy (MMN) is a chronic immune-mediated disorder associated with long-term disability and reduced quality of life (QoL). Longitudinal real-world data on QoL in MMN are scarce, particularly during the COVID-19 era. This study aimed to evaluate long-term changes in QoL and disease outcomes in MMN patients over a 6-year follow-up and to assess the multidimensional impact of the COVID-19 pandemic.

METHODS

Twelve MMN patients were re-evaluated 6 years after baseline assessment. Functional disability was assessed using the INCAT disability score and I-RODS scale. QoL was measured using the SF-36 questionnaire, while depressive symptoms and fatigue were evaluated using the Beck Depression Inventory (BDI) and Fatigue Severity Scale (FSS). Pandemic-related impact was assessed using a specifically designed questionnaire.

RESULTS

Functional disability remained overall stable during follow-up (INCAT total score 3.4 ± 2.2 vs. 3.3 ± 1.9). However, fatigue and depressive symptoms increased significantly, with the prevalence of fatigue rising from 17 to 58% and depression from 8 to 25% (p < 0.05). Mean FSS scores increased from 20.1 ± 13.3 to 35.3 ± 15.0, and BDI scores from 3.3 ± 7.8 to 9.2 ± 15.4. Physical QoL domains declined over time, particularly Physical Functioning (76.7 ± 29.9 to 57.5 ± 31.6) and Bodily Pain (82.8 ± 28.9 to 71.7 ± 28.5), while mental domains remained relatively preserved (MCS 69.1 ± 19.5 vs. 69.4 ± 21.3). During the COVID-19 pandemic, 33% of patients developed SARS-CoV-2 infection, 17% experienced treatment interruption, and one patient died from severe COVID-19.

CONCLUSION

Long-term immunotherapy in MMN appears to stabilize motor disability but does not prevent the progressive increase of fatigue and depressive symptoms, which emerge as major contributors to long-term disease burden. The COVID-19 pandemic further affected healthcare access and psychosocial wellbeing. These findings support routine screening for fatigue and mental health symptoms and highlight the need for a multidisciplinary approach to MMN management.