Inclusion Criteria:  Clinically defined or probable diagnosis of ALS according to El Escorial criteria revised with Awaji's electro-diagnostic algorithm. Over 18 years old. Signed informed consent If patient on Riluzole, the dosage should be stable for 1 month and continued throughout the study period.  Exclusion Criteria:  Patients with excessive cognitive disorders, limiting the understanding of task or with apparent communication difficulties hindering data collection. Any other previous or present pathology having an impact on motor function. Recent surgery or trauma (less than 6 months) in the upper or lower limbs. Prior neurological, endocrine, infectious, allergic, or chronic or acute inflammatory pathology in the three weeks preceding inclusion. Patients participating in an interventional clinical trial.