Diagnostic and therapeutic choice in neurology can fortunately be made without formal decision support in the majority of cases. in many patients a diagnosis and treatment choice are relatively easy to establish. This study however, concerns the application of a decision support methodology - clinical decision analysis - to several problems in the clinical neurosdences where diagnosis, prognosis and therapeutic choice are not obvious. Sometimes decision making in clinical medicine can be extremely difficult There may be large interests atstake,and theamount of information that has to beprocessed can be enormous. Data from the patient's history, physical examination, diagnostic procedures, clinical knowledge and the scientific information have to be combined in order to arrive at a prognosis and to develop a diagnostic and therapeutic strategy. Add to this that most diagnostic tests are not completely accurate, that therapy is not always and entirely effective, that diagnostic and therapeutic procedures may be risky, unpleasant, expensive and time-consuming, and that prognosis is most of the times uncertain. The decision process itself is limited by time and by budgetary constraints. The clinician has to recognize situations where the patient's preferences are important, and he has to know when the clinical situation needs a doctor - patient relationship characterized by activity - passivity, guidance - cooperation or mutual participation. Moreover, physicians and their patients (as any human being) find it difficult to handle uncertainty.'" Oinicians often discuss the pro' s and con' sof altemativemanagementstrategies with their senior and junior colleagues, but a language that effectively and explicitly addresses uncertainty and preferences for health outcomes is not part of the physician's standard equipment. Several other factors influence the decision process as welL It has been demonstrated that patient characteristics, (such as social class), physician's personal characteristics (such as age, type of specialty), and the physician's interaction with his profession (for example whether he is in a solo- of group-practice) all may be of influence.