Described are methods, devices, and systems for a novel, inexpensive, easy to use therapy for treatment of coma, post-traumatic stress disorder, Parkinson's disease, cognitive performance, and/or amblyopia. Described are methods and devices to treat coma, post-traumatic stress disorder, Parkinson's disease, cognitive performance, and/or amblyopia that involves no medication. Methods and devices described herein use alternating magnetic fields to gently 'tune' the brain and affect symptoms of coma, post-traumatic stress disorder, Parkinson's disease, cognitive performance, and/or amblyopia. 
Systems and methods for modulating the electrical activity of a brain using neuro-EEG synchronization therapy