Open-label Clinical Trial of Lacosamide in ALS

Inclusion Criteria: * Over 20 year old * Probable or definite ALS disease evaluated by Awaji electrophysiological criteria * Subjects provided informed consent. Exclusion Criteria: * Patient without ability to comprehend informed consent * Patient with uncompensated medical illness * Patient with cardiac disease (myocardial infarction, valvular disease and cardiomyopathy etc.) * Patient with arrhythmia (incomplete atrioventricular block and bundle branch block etc.) * Patient with sodium channel disorders, such as Brugada syndrome * Patient already administered anti-arrhythmic drug which prolongs PR interval (interval between arterial and ventral contraction measured by ECG) * Pregnant or breast-feeding woman * Patient with forced vital capacity of \< 60% predicted * Patient already performed tracheotomy or tube feeding * Patient who takes any other experimental agents 3 months before. * Not enough compound muscle action potential amplitude in the median nerve to be performed nerve excitability test * Patient who plans to change medicine which affects nerve excitability during this trial 4 weeks * Familial ALS * Patient who is judged inappropriate for this trail by doctors responsible for this trial