Can electrophysiology differentiate polyneuropathy with anti-MAG/SGPG antibodies from chronic inflammatory demyelinating polyneuropathy?

Clin Neurophysiol. 2002 Mar;113(3):346-53. doi: 10.1016/s1388-2457(02)00011-1.


Objectives: Patients with polyneuropathy and antibodies to myelin-associated glycoprotein (MAG) and sulphated glucuronyl paragloboside (SGPG) differ from chronic inflammatory demyelinating polyneuropathy (CIDP) because of a slower, progressive course, symmetrical and predominantly sensory involvement of legs, predominantly distal slowing of motor conductions, and poorer response to therapy. We studied whether a wide set of electrophysiologic parameters may differentiate these two neuropathies.

Methods: We reviewed the electrophysiological studies of 10 patients with anti-MAG/SGPG antibodies and 22 with CIDP examining: (1) motor conduction velocity and distal compound muscle action potential amplitude; (2) conduction block (CB) and temporal dispersion; (3) distal motor latency and terminal latency index (TLI); (4) F wave and proximal conduction time; and (5) sensory conduction and occurrence of abnormal median with normal sural sensory potential.

Results: Anti-MAG/SGPG neuropathies showed: (1) more severe involvement of peroneal nerves; (2) more frequent disproportionate distal slowing of motor conductions (TLI< or =0.25) and absent sural potential, and (3) no CB. However 3/22 CIDP patients also had at least two nerves with TLI< or =0.25 and no CB.

Conclusions: Electrophysiologic findings suggest in anti-MAG/SGPG neuropathy a length-dependent process with a likely centripetal evolution. A disproportionate slowing of conduction in distal segments of motor nerves suggests the diagnosis of anti-MAG/SGPG neuropathy, although it is not pathognomonic.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Autoantibodies* / blood
  • Diagnosis, Differential
  • Electric Stimulation
  • Electrodiagnosis / methods*
  • Electrophysiology / methods*
  • Female
  • Globosides / immunology
  • Humans
  • Male
  • Middle Aged
  • Myelin-Associated Glycoprotein / immunology
  • Neural Conduction
  • Peroneal Nerve / physiopathology
  • Polyneuropathies / blood
  • Polyneuropathies / diagnosis*
  • Polyneuropathies / immunology
  • Polyradiculoneuropathy, Chronic Inflammatory Demyelinating / diagnosis
  • Predictive Value of Tests
  • Reaction Time
  • Retrospective Studies
  • Sural Nerve / physiopathology


  • Autoantibodies
  • Globosides
  • Myelin-Associated Glycoprotein
  • sulfate-3-glucuronyl paragloboside