On the day of the study, the patient comes to the office with clean hair with no hair products. The patient may follow all other regular routines, including eating and medication (unless instructed otherwise by the doctor). The patient should avoid foods and drinks containing caffeine for two hours before the DESA®. After an explanation of the procedure, the patient sits in a recliner. The technician places a specially designed cap containing thirty-two electrodes on the patient’s head. Electrogel, a clear pasty substance, is used to insure proper contact with the predetermined points on the scalp, ears, neck, and cheek. There is nothing of a painful nature involved in the procedure. The collection of data begins. The patient need not do anything more than sit quietly. Once the technician determines that all pertinent information has been collected, the patient’s cap is removed and the patient may leave.