There are various research papers published that illustrate beneficial effect of diadynamic and galvanic currents on people suffering from variety of conditions such as:

migraine, neuralgia, bronchitis, colitis, endometriosis, urethral stricture, Raynaud's phenomenon, anxiety, various musculoskeletal disorders, poststroke symptoms, Parkinson's Disease, cerebral palsy, etc. Links to the research papers available on request.