Amplification

This paper reviews recent developments in amplification for hearing-impaired listeners. Because of the large number of studies devoted to this topic, this review is restricted to acoustical stimulation of the hearing sense after electrical amplification, with a focus on the technical and audiologic aspects of hearing instruments only. Electrical or vibratory stimulation and developments using implantation technology for cochlear implants, middle-ear implants, or bone-conduction implants will not be discussed. Although, nontechnical factors, eg, preference or acceptance by hearing-impaired users, frequently determine the final effect of a hearing aid, they are beyond the scope of this paper. Developments in fitting strategies and evaluation techniques, however, will be addressed.