[Grading the voice: pitfalls and advantages].

All functional exploration, and that of the voice is not an exception to the rule, calls for "setting values". The need for a quantification fo the human voice is legitimate but may lead to the contrary of the goal sought if a few basic principles are not respected and may supply some erroneous pathological results. The imperatives are linked together by a strict protocol, knowledge of measured parameters and the manner in which the signal treatment supplies them. We shall show, step by step, the utility of applying these principles with a few concrete examples.