PRACTICEPARAMETERSANDTECHNOLOGY ASSESSMENTS:WHATTHEYARE,WHATTHEY ARENOT,ANDWHYYOUSHOULDCARE To the Editor: I read with interest the recent invited article by Drs. Gronseth and French,1 where the authors describe several important points regarding the mechanism by which the American Academy of Neurology (AAN) initiates and proceeds with the development of the guidelines. I was surprised to learn, from recent correspondence in Neurology, that Practice Guidelines can be published although some panel members may disagree.2 Once experts are selected to formulate guidelines, this is presumably done based on the assumption that they are knowledgeable in the field and with the hope that the process of deliberation may lead them to reach a common view. Of course, a consensus cannot always be obtained and if this occurs, when 2 (or more) sets of conclusions are reached, it is inappropriate to disregard some and to only publish one set, even if supported by a majority. Scientific truth cannot be decided by a popular vote, and therefore both sets of conclusions should be published side by side. The oversight mechanism which Drs. Gronseth and French mention is, unfortunately, not transparent. This is particularly relevant to cases where one set of conclusions is adopted and another rejected. I think this issue needs to be discussed and reconsidered.