A method for treating patients with Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig's disease. In accordance with the method of treatment, transcranial AC pulsed electromagnetic fields (EMFs) in substantially square waveforms in particular frequency and amplitude ranges and picotesla quantities are applied to the patient's brain. EMFs are applied via a transducer array containing a plurality of flexible circular coils in an arrangement placed over the scalp of an ALS patient. The treatment method ameliorates symptoms associated with the disease state and slows the progression of the disease.