Terminal latency index in neuropathy with antibodies against myelin-associated glycoproteins.

Abstract

Neuropathy with antibodies against myelin-associated glycoproteins (MAG/SGPG-N) and hereditary sensorimotor neuropathy type 1 (HMSN1) are characterized by chronic demyelination with little conduction block. Electrodiagnostic studies suggest that in HMSN1 conduction slowing occurs uniformly along the nerve, whereas in MAG/SGPG-N it is predominantly distal. Some but not all previous reports have shown that the terminal latency index (TLI) was useful to distinguish MAG/SGPG-N from chronic idiopathic demyelinating polyneuropathy. We compared median TLI from 21 patients with MAG/SGPG-N with those obtained from 26 patients with HMSN1, 20 with HMSN2, and 12 healthy volunteers. All patients with TLI <0.26 had MAG/SGPG-N, and all patients with TLI > or =0.32 had HMSN1. In the remaining patients with intermediate TLI values, ulnar distal motor latency (DML) aided in differentiation between MAG/SGPG-N and HMSN1 with an overall sensitivity of 100% and specificity of 98%. In conclusion, median TLI in combination with ulnar DML can further guide the demyelinating neuropathy evaluation toward hereditary or autoimmune causes.

• Authors: Vitalie D Lupu, Carlos A Mora, Jim Dambrosia, Jacob Meer, Marinos Dalakas, Mary Kay Floeter
• Journal: Muscle & nerve (Muscle Nerve) Vol. 35 Issue 2 Pg. 196-202 (Feb 2007) ISSN: 0148-639X [Print] United States
• PMID: 17068765 (Publication Type: Comparative Study, Journal Article, Research Support, N.I.H., Intramural)

Chemical References

• Antibodies
• Myelin-Associated Glycoprotein

Topics

• Action Potentials (physiology, radiation effects)
• Adult
• Aged
• Antibodies (blood)
• Charcot-Marie-Tooth Disease (physiopathology)
• Electromyography
• Female
• Humans
• Male
• Median Nerve (physiopathology)
• Middle Aged
• Myelin-Associated Glycoprotein (immunology)
• Neural Conduction (physiology)
• Peripheral Nervous System Diseases (immunology, physiopathology)
• Reaction Time (physiology)
• Ulnar Nerve (physiopathology)