[Clinical reasoning in neurology]

There is much neurological literature on clinical, pathological, technical aspects of diagnostic or therapeutic aspects, however there are few articles about clinical-neurological reasoning. This paper analyzes the psychological processes by which neurologists solve complicated diagnostic problems. Clinicians can use a variety of reasoning, such as model (pattern), exhaustive, probabilistic, deterministic (categorical), and hypothetical-deductive reasoning mechanisms. The neurologist must be aware of what kind of reasoning is being used at a given time as well as the errors that can occur. Most of these errors are found in the probabilistic setting and can be grouped into three categories: representativeness errors, availability or adjustment and anchoring biases. Most of them occur due to an inadequate intuitive judgement by the physician to handle the probabilities. There are other sources of error, related with the diagnostic process or with the environmental circumstances in which they develop. The most important ones as well as their theoretical and practical implications are described. In the evidence based medicine era, it is important for the clinical neurologists to be aware of this terminology and concepts for an adequate practice of neurology.