Distal motor latency and residual latency as sensitive markers of anti-MAG polyneuropathy.
There is debate whether the terminal latency index (TLI) is a sensitive marker for polyneuropathy with anti-myelin-associated-glycoprotein antibodies (anti-MAGP). We examined 6 patients with an anti-MAGP and 6 patients with a chronic inflammatory demyelinating polyneuropathy (CIDP). The electroneurographic features studied were: distal compound motor action potential (CMAP), distal motor latency (DML), motor conduction velocity (MCV) elbow to wrist (distal MCV), MCV axilla to elbow (proximal MCV), MCV distal/proximal, terminal latency index (TLI), residual latency (RL), F-wave, and modified F ratio. We found significant differences between anti-MAGP and CIDP for DML and for RL. No significant differences were found for TLI and the other measures. The TLI values were not significant probably because our patients had a longer duration of disease,which supports the hypothesis of a distal to proximal progression of conduction slowing over time. We propose that a residual latency >4.0 and a distal motor latency >7.0 are strongly suggestive for an anti- MAGP.
Radziwill
Alexander J
AJ
Dept. of Neurology, University Hospital, Lausanne, Switzerland. aradziwill@gntmed.ch
Steck
Andreas J
AJ
Renaud
Susanne
S
Fuhr
Peter
P
D000200:Action Potentials; D000328:Adult; D000368:Aged; D000906:Antibodies / Q000378:metabolism*; D015415:Biomarkers; D004550:Elbow / Q000294:innervation / Q000502:physiology; D004594:Electrophysiology; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008875:Middle Aged; D018992:Myelin-Associated Glycoprotein / Q000276:immunology*; D009431:Neural Conduction; D010523:Peripheral Nervous System Diseases / Q000276:immunology / Q000503:physiopathology; D020277:Polyradiculoneuropathy, Chronic Inflammatory Demyelinating / Q000276:immunology / Q000503:physiopathology*; D011930:Reaction Time / Q000502:physiology; D012196:Review Literature as Topic; D014459:Ulnar Nerve; D014953:Wrist / Q000294:innervation / Q000502:physiology
D000906:Antibodies; D015415:Biomarkers; D018992:Myelin-Associated Glycoprotein