Hearing aid systems in undeveloped, developed and industrialized countries.

The problems related with the hearing loss prevalence and deafness rehabilitation in Developing (D) countries are so complex that only basic needs and some suggestions are discussed in this paper. In fact for D countries the main demographic and social indi reveal the enormous gravity of the health situation and so the availability of a hearing aid delivery system is often considered less urgent and secondary to the basic unmet needs of the population. Nevertheless we think this concept may be applied to the adult, but for the child with a preverbal deafness it must deserve immediate attention in order to prevent a very serious handicap limiting all his life. Schematically the three types of handicaps developed by a child with a preverbal hearing loss are presented and discussed. The essential assumption, however, for any hearing aid program in D countries is the creation in loco of competent personnel for the prescription, for fitting and checking the aids. If D countries are to achieve this objective, industrialized countries must begin to transfer technology and training to develop pilote centers.