[The definition of "selectivity" in reduced speech discrimination as a sequela of peripheral perceptual damage].

The term "selectivity" means the ability to correctly select speech in the presence of other kinds of noise. In the literature the term "selectivity" is used very differently with regard to the different levels of the hearing system. In actual practice a separation of this term is important for possible audiometric topodiagnosis study. The problems of selectivity in hearing are discussed and different terms are proposed regarding the different planes of hearing system: 1. for the interaural-external ear transfer function, the terms "stereophonic outer ear effect" or "stereophonic outer ear efficiency" are used; 2. for the power of the inner ear, the term "ability of analysis"; 3. for the central auditory pathways, the term "chiasmatic selectivity" or "meshing selectivity"; 4. for the cortical centre, "active selectivity." The audiometric test batteries used clinically for topodiagnosis are discussed and two examples shown to illustrate the usefulness of the distorted Freiburg Word Test for detecting "analytical ability" in cases of inner ear damage.