Table 1 Characteristics of 20 patients with MMN.

Characteristic
Number (%) male sex	15 (75%)
Mean (SD) age at onset (years)	34.4 (8.1)
Mean (SD) years untreated	6.9 (6.6)
Mean (SD) years treated	4.5 (2.4)
Number (%) with upper limb onset	14 (70%)
Mean (SD) MRC sum score for arms	41 (6)
Number (%) with raised anti‐GM1 antibodies*	5 (31%)
Number (%) with abnormal MRI brachial plexus	8 (40%)

MRC sum score arm: summation of MRC scores, which were bilaterally determined in 5 arm muscles (maximum values, 50). Abnormal MRI brachial plexus: swelling and/or increased signal intensity on magnetic resonance imaging.

*Investigated in 16 patients.

MRC, Medical Research Council; MRI, magnetic resonance imaging.