“…A further difficulty in defining the specific clinical picture for the patient is that tics may change during the course of illness and new tics can issue (Du, 2010 ; Liao, 2010 ; Worbe, 2010 ). The development of diagnostic instruments that try to bypass the timing of the different clinical manifestations, such as the Diagnostic Confidence Index (Robertson, 1999 ), demonstrate the need for a sound description of such an ever-changing clinical picture.…”