Skip to main content
. 2011 Feb 16;2011(2):CD003279. doi: 10.1002/14651858.CD003279.pub3

Wirtz 2009.

Methods Randomised double‐blind placebo controlled cross‐over trial
Participants 9 adults with LEMS fulfilling the diagnostic criteria of AAEM (2001)
Interventions 10 mg IV 3,4‐DAP infused over 60 mins for one treatment session.Then varying doses of IV pyridostigmine were infused over 1 minute, 40 minutes apart during the previously described 3,4‐DAP infusion. A further session of IV pyridostigmine only was conducted, together with double dummy placebos for the infusions and boluses
Outcomes Primary: (1) Isometric muscle strength (hip flexion)
(2) Changes in the CMAP of the hypothenar muscles of the nondominant hand
Secondary: (1) Decrement of CMAP amplitude during 3 Hz repetitive nerve stimulation and its increment after 10 s of maximum voluntary contraction
Notes Significant improvement in isometric muscle testing and resting CMAP amplitude following 3,4‐DAP treatment. No additional benefit with the addition of pyridostigmine, and pyridostigmine in isolation showed no difference to the placebo group
Risk of bias
Bias Authors' judgement Support for judgement
Adequate sequence generation? Low risk A random assignment table was used
Allocation concealment? Unclear risk No information given about the randomisation process in either the full article or in the supplementary information online, and it was unclear who 'held' the random assignment table
Blinding? 
 All outcomes Low risk Blinding of participants and key study personnel was ensured. However, it was not stated whether placebo infusions appeared identical to 3,4‐DAP infusions, though this would not affect objective neurophysiological testing
Incomplete outcome data addressed? 
 All outcomes Low risk 2 participants were unable to undertake the final session for reasons that were well explained. It is unlikely that these missing outcomes have a clinically relevant impact on observed effect size
Free of selective reporting? Low risk All of the study's pre‐specified (primary and secondary) outcomes were reported in the pre‐specified way in keeping with their methods
Free of other bias? Low risk The study appears to be free of other sources of bias

1. LEMS: Lambert‐Eaton myasthenic syndrome 
 2. AAEM: American Association of Electrodiagnostic Medicine 
 3. IVIg: intravenous immunoglobulin 
 4. 3,4‐DAP: 3,4‐diaminopyridine 
 5. CMAP: compound muscle action potential