Use of QTRAC Technique to Measure Axonal Excitability in Anti-MAG Neuropathy
Use of QTRAC Technique to Measure Axonal Excitability in Anti-MAG Neuropathy
The QTRAC method is an electrophysiological technique that assesses peripheral nerve axonal
 excitability, using computerized analysis of the muscular response of musculus abductor
 pollicis brevis, to series of electrical stimulations of the median nerve.

 Because of its high sensitivity to small changes in axonal excitability, QTRAC may help
 improve the follow-up of patients suffering from peripheral neuropathy caused by
 anti-myelin-associated-glycoprotein antibodies (anti-MAG neuropathy), as axonal excitability
 is early affected in this disease.

 The main aim of the study is to compare QTRAC results in anti-MAG neuropathy patients, with
 QTRAC results in healthy persons (matched for sex and age).

 A secondary aim is to determine whether or not the disease's clinical severity (measured by
 quantitative clinical scores) is correlated with the results of the QTRAC and could be
 predicted by a model based on the several parameters measured in the QTRAC exploration.

 100 anti-MAG neuropathy patients will undergo a QTRAC exploration and a thorough neurological
 examination with clinical scoring. The results will be compared with data (matched by sex and
 age) from the reference database on healthy subjects, that is provided with the QTRAC
 software.

 The investigators expect to prove that QTRAC results are modified in anti-MAG neuropathy
 patients, and that the clinical severity of the disease can be predicted by a combination of
 QTRAC-measured parameters.
Inclusion Criteria:

 -  Anti-MAG neuropathy (peripheral neuropathy and IgM monoclonal gammopathy with anti-MAG
 activity superior to 1000 BTU)

 Exclusion Criteria:

 -  current treatment with a medication that modifies peripheral nerve excitability (e.g.
 anticonvulsivants)