From an antique Master Violet Ray manual c. 1920 comes this treatment advice: Brain Fog - Use Applicator No. I over forehead and eyes. Also treat the back of head and neck with strong current in direct contact with the skin. Treat the spine and hold the electrode in the hand. Ozone inhalations for about four minutes are also of importance.
I still don't understand the use of an oscilloscope with such devices :-(