This study is being conducted to help the investigators better understand how the new FDA approved medication Edaravone (also known as Radicava) works in subsets of patients with ALS. The investigators are also trying to understand if there are specific ALS patients, with different presentations of ALS, who might benefit most from this medication. Also, the investigators are following specific biomarkers to determine the optimal treatment duration in patients with different forms of ALS

There is no study medication being offered in this trial. Edaravone is prescribed as part of regular care. In this trial we are collecting blood, urine, and spinal fluid samples in ALS patients who are taking Edaravone and ALS patients who are not taking Edaravone to measure certain markers that could indicate why the drug may be working in a specific type of ALS.

Inclusion Criteria:

1. Either possible, probable, or definite ALS, predominantly lower motor neuron disease, predominantly upper motor neuron disease, or bulbar
2. With or without cognitive involvement
3. Willing to participate
4. On no experimental treatment
5. Ages 18 - 85
6. No prior exposure to Edaravone (Radicava)
7. On a stable dose of Riluzole for 30 days or off Riluzole
8. Male or female
9. Females of childbearing age must use contraception

Exclusion Criteria:

1. Unstable medical illness
2. Abnormal liver function (>2x ULN)
3. Unlikely to survive for 26 weeks

Anyone who meets the Inclusion/Exclusion Criteria