* Asymmetric = a difference of 1 MRC grade if strength is MRC >3 and 2 MRC grades if strength is MRC ≤3 † Usually more than 6 months ‡ Sensory signs and symptoms may develop over the course of MMN § At onset, predominantly lower limb involvement account for nearly 10% of the cases ¶ Slightly increased tendon reflexes, in particular in the affected arm, have been reported and do not exclude the diagnosis of MMN provided criterion 8 is met ** Twelfth nerve palsy has been reported *** Evidence for CB must be found at sites distinct from common entrapment or compression syndromes Definite motor CB = Negative peak CMAP area reduction on proximal vs. distal stimulation of at least 50% whatever the nerve segment length (median, ulnar, and peroneal). Negative peak CMAP amplitude on stimulation of the distal part of the segment with motor CB must be >20% of the lower limit of normal and >1 mV and increase of proximal to distal negative peak CMAP duration must be ≤30% Probable motor CB = Negative peak CMAP area reduction of at least 30% over a long segment (e.g., wrist to elbow or elbow to axilla) of an upper limb nerve with increase of proximal to distal negative peak CMAP duration ≤30% OR Negative peak CMAP area reduction of at least 50% (same as definite) with an increase of proximal to distal negative peak CMAP duration >30%