If this is anything like Neurofeedback treatment, it wouldn't surprise me that it is effective. Neurofeedback treats 3 major frequency ranges of the brain, Delta, Theta and Alpha. Although this treatment seems passive whereas Neurofeedback treatment requires active modulation and stimulation by the person getting the treatment.
Going through Neurofeedback treatment myself and seeing the incredible life changes because of it and now seeing the similarity of the affected brain regions in this study shows that there might be some consensus reached on treating these conditions without medication one day.