[Hearing in advanced age: critical view of so-called presbycusis]

Presbycusis cannot be defined nosologically as an uniform disease. The computed threshold curves of the age dependent high-frequency hearing loss should not conceal the fact that the degree and form of the hearing loss vary greatly within the age groups. The pathological appearances also vary; degenerative changes vary in site and extent and are not limited to the cochlear structures, but are also found in all parts of the auditory system. The etiology of presbycusis can scarcely be attributed to the physiological senile degeneration of cochlear or central nervous structures alone because epidemiological studies suggest that without additional endogenous and exogenous noxious effects the hearing loss progresses more slowly than under the influence of these effects. Therefore, presbycusis, in the sense of a socially handicapping hearing loss, is not an invariable lesion of the auditory system (mainly of the inner ear) due to a combination of different etiological factors. There are only two possible treatments: (1) elimination of exogenous and endogenous noxious effects in the hope of delaying the progress of the hearing loss and (2) fitting of a hearing aid. The open high-tone CROS-aid seems to provide a sufficient discrimination gain which is especially valuable for the typical high tone hearing loss in aged people. The necessity for a careful follow-up is emphasised.