Swan I R, Browning G G, Gatehouse S
Br J Audiol. 1987 Feb;21(1):59-65. doi: 10.3109/03005368709077775.
The criteria generally used to decide in which ear to fit a monaural hearing aid are based on theory or anecdote and have not been verified by experimental observation. In this study to determine optimum side of fitting, 58 new hearing aid users were fitted with a hearing aid in one ear for 10 weeks, and then fitted in the other ear for a further 10 weeks. Subsequently, the subjects were asked their preference for side of hearing aid use and their reasons for this preference. 30 (52%) subjects reported better hearing with their aid in one ear than in the other; 24 (80%) of these preferred the ear with the poorer half-peak level elevation on a speech audiogram. The remaining 28 (48%) reported no difference in their aided hearing ability between ears, though 20 preferred one ear for practical reasons, unrelated to audiometric parameters. A patient's preference for side of fitting can be predicted from audiometric data but with only modest reliability. It is, therefore, recommended that bilateral ear moulds should be routinely provided for bilateral mild to moderate hearing impairment (speech frequency average less than 75 dB HL). If it is decided that only one ear mould should be provided, this should be made for the poorer hearing ear. The poorer hearing ear is best identified from the half-peak level elevation on a speech audiogram.