Premium
Length dependence in polyneuropathy associated with IgM gammopathy
Author(s) -
Franssen Hessel,
Notermans Nicolette C.
Publication year - 2006
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.20785
Subject(s) - chronic inflammatory demyelinating polyneuropathy , medicine , polyneuropathy , gammopathy , ulnar nerve , nerve conduction velocity , median nerve , nerve conduction , axon , elbow , wrist , electromyography , anatomy , antibody , immunology , monoclonal , monoclonal antibody , physical medicine and rehabilitation
Objective In polyneuropathy associated with monoclonal IgM gammopathy, nerve conduction studies may show disproportionate distal slowing consistent with segmental demyelination. This was suggested to represent a length‐dependent demyelinating process, starting in distal and proceeding to proximal segments. Because the evidence for this is incomplete, we assessed whether length dependence occurs in IgM neuropathy. Methods In 22 patients with IgM neuropathy, 20 disease controls with chronic inflammatory demyelinating polyneuropathy (CIDP) and 36 normal controls, we investigated motor conduction, sensory conduction, and needle electromyography for nerves with short, intermediate‐length, and long axons as well as conduction in short segments of the ulnar nerve from proximal to distal. To compare variables in nerves of different length, we normalized individual values with respect to the median in normal controls. Results In IgM neuropathy, distal slowing and features of axon loss increased with nerve length, and ulnar nerve conduction became gradually slower from proximal to distal when the elbow segment was excluded. In CIDP, no clear length dependence was found except for distal amplitude. Interpretation The disproportionate distal slowing in IgM neuropathy may be part of a length‐dependent process, assuming that this process is randomly distributed due to a generalized exposure to IgM. Ann Neurol 2006;59:365–371