Table 2 American Academy of Neurology system for translation of evidence to recommendations

Rating of recommendationsTranslation of evidence to recommendations
A = Established as useful/predictive or not useful/predictive for the given condition in the specified populationLevel A rating requires at least one convincing class I study or at least two consistent, convincing class II studies
B = Probably useful/predictive or not useful/predictive for the given condition in the specified populationLevel B rating requires at least one convincing class II study or overwhelming class III evidence
C = Possibly useful/predictive or not useful/predictive for the given condition in the specified populationLevel C rating requires at least two convincing class III studies
U = Data inadequate or conflicting. Given current knowledge, test, predictor is unproven.