[SBU with its ear to the ground. Hearing aids benefit mainly those with moderate hearing loss].
This review focused on answering the following questions: 1. At what level of hearing loss can hearing aids be of sufficient benefit to motivate testing and prescribing? 2. What is known about the value of the various technical features in modern hearing aids? English language literature was searched for the period 1990 through December 2002 using Medline. The scientific quality of the retrieved literature was assessed by two reviewers. Hearing aids benefit mainly those with moderate to severe hearing loss. Hearing aids amplify sound but do not provide normal hearing. In regard to sound quality and benefits in daily life, non-linear technology is better than linear. There is no evidence that digital hearing aids are superior to modern analog hearing aids. No clinical trials have shown that two hearing aids are superior to one hearing aid. The need for further scientific studies is substantial.