Eligible patients should have a diagnosis of definite ALS according to the El Escorial revised criteria with clear clinical upper and lower motor neuron signs. Twenty patients with definite ALS will be enrolled and will be allocated to the treatment: 10 active and 10 sham stimulation. Patients will be randomly allocated by one of the investigators not involved in follow-up evaluations and data analysis. Stratified block randomisation will be performed such that the two treatment groups will be evenly balanced for disease severity, as evaluated with the revised ALS functional rating scale (ALSFRS-R), and duration. The patients and the neurologists assessing the outcomes will be blinded to group assignment.