Subjects will be recruited from ALS clinics that are a part of the Canadian ALS Neuroimaging Consortium (CALSNIC). Patients will have a diagnosis of ALS, PLS, PMA, or FTD. Healthy controls will be age and gender matched to patients. Subjects will visit their respective sites to undergo a clinical evaluation and an MRI. Follow up visits will occur at approximately 3-6 month intervals. Most subjects will have 2 follow up visits; more visits may occur for subjects who are physically able to continue in the protocol.