[Progressive ataxia and falls in a 62 year old woman]

We discuss the diagnostic workup of a 62 year old woman without any significant past medical history. We take this opportunity to point out three aspects : 1. The necessary contextualization of the whole process allowing to avoid unrealistic differentials; 2. The requirement to prioritize the diagnostic tests as a function of their expected contribution to the diagnosis, their invasive characteristic and their availability, including their cost and 3. The evolving character of the diagnostic process that, if needed, has to be reconsidered to integrate the information obtained from the first diagnostic tests and the evolution of the patient.