[Diagnostic reasoning in neurology. An analysis of the more frequent errors]

Diagnostic reasoning is a cognitive proccess that has various performance and results. There are several kinds of clinical reasoning, such as model or pattern recognizing, causal or physiopathologic reasoning, deterministic, exhaustive, and hypotetic-deductive ones. Each form of reasoning may be relevant in certain clinical context, and all of the forms are also complementary. The logical consequence of diagnostic reasoning, like every cognitive proccess, is a clinical error. It is necessary that the neurologist knows the principles of diagnostic reasoning and the more frequent errors and biases. These can be summarized as: errors associated with the proccess of taking history and clinical examination, mnesic and semantic components of clinical reasoning, failure of hipotetic- deductive reasoning, and inadequate use of probability theory in Medicine.