A method is provided for the suppression or prevention of pain, movement disorders, epilepsy, cerebrovascular diseases, autoimmune diseases, sleep disorders, autonomic disorders, abnormal metabolic states, disorders of the muscular system, and neuropsychiatric disorders in a patient. The method comprises inserting an electrode into a patient. The electrode can be positioned on or proximate to a neural structure, and the electrode can detect an ENG signal. In some embodiments, the neural structure can be the patient's sphenopalatine ganglia (“SPG”), sphenopalatine nerves (“SPN”), or vidian nerves (“VN”). Placement of the electrode can be tested by detecting a characteristic ENG. If the characteristic ENG indicates that the electrode is not positioned on the target neural structure, the electrode can be repositioned.
