Abstract
A co-ordinated clinical trial of In-the-Ear hearing aids (ITE) and comparison with Behind-the-Ear hearing aids (BTE) has been carried out at five hearing centers in Sweden. A common protocol for evaluation has been used, containing audiometric evaluation, questionnaire regarding satisfaction of acoustic function and manageability, tests for perceived sound quality and speech discrimination in sound field. A total of 211 patients participated in the test, all experienced hearing aid users. Eight different ITE-aids were tested. 72% of the patients preferred the ITE-aid to their former BTE-aid, while 24% preferred the BTE-aid. Evaluation of the questionnaires showed that many subjects preferred the ITE-aid when listening to speech in background noise and when perception of sound source direction is important. Cosmetically a majority of the subjects preferred the ITE-aid. Problems with acoustic feedback were somewhat more common with ITE- than with BTE-aids. Also with regard to manageability some differences could be seen. Speech discrimination in sound field with background noise showed a clear improvement with the ITE-aid. The subgroup which preferred the ITE-aid after the test showed a significant increase in speech discrimination scores as compared to when using their BTE-aids, while those who preferred their BTE-aids did not show any significant improvement in speech discrimination score with the ITE-aid. Also the test for perceived sound quality showed a superior performance for the ITE-aid in the subgroup which preferred that type.