Patients with anti-MAG neuropathy have uniform slowing without temporal dispersion, but do usually have disproportionately distal slowing. We evaluated distal compound muscle action potential (CMAP) dispersion in 29 patients with anti-MAG/SGPG neuropathy (titers >=12800). Among 138 motor responses, 15% (tibial), 7.3% (peroneal), 10.7% (median) and 13.8% (ulnar) had distal CMAP duration > 9 ms. Disproportionate distal slowing with normal distal CMAP duration in the arms may be useful to differentiate CIDP from anti-MAG/SGPG associated neuropathy.
- myelin-associated glycoprotein
- peripheral neuropathy
- temporal dispersion