Rm. Van Den Berg-vos et al., Multifocal motor neuropathy: Diagnostic criteria that predict the responseto immunoglobulin treatment, ANN NEUROL, 48(6), 2000, pp. 919-926
As multifocal motor neuropathy (MMN) is a potentially treatable disorder, i
ts differentiation from lower motor neuron disease is important. Evidence o
f conduction block (CB) is considered one of the relevant criteria for the
diagnosis of MMN. Strict criteria for CB may lead to underdiagnosis of MMN,
however. Using a standardized examination, we studied the clinical, labora
tory, and electrophysiological characteristics of 37 patients presenting wi
th a lower motor neuron disorder and electrophysiological features compatib
le with segmental demyelination. We propose a set of clinical, laboratory,
and electrophysiological criteria for the diagnosis of MMN, which has been
verified by follow-up and response to treatment with intravenous immunoglob
ulins. Based on the clinical, laboratory, and electrodiagnostic features, 2
1 patients were diagnosed with definite MMN (17 responders), 7 were diagnos
ed with probable MMN (5 responders), and 9 were diagnosed with possible MMN
(1 responder). Age at onset, the number of affected limb regions, and the
number of patients with a creatine kinase level greater than 180 U/L were s
ignificantly lower in responders than in nonresponders. Elevated anti-GM1 a
ntibodies and definite CB were found significantly more often in responders
. The proposed diagnostic criteria may be useful in clinical practice and t
herapeutic trials.