A Patient Diary is a tool used during a clinical trial or a disease treatment to measure treatment compliance. Electronic patient diaries is also available. An electronic patient diary registers the data in a storage device and allows for monitoring the time of medication and symptoms. Patient Diary is used in the holter monitor to monitor 24 hour period and records the electrical activity of the heart over this time. Patient diaries are way to find out if a patient takes the medication according to the treatment schedule, which is an important problem during clinical trials and the treatment of degenerative diseases with relatively few symptoms.