Hearing aids and tinnitus--an experimental group study.

From a waiting list consisting of hearing-impaired patients waiting for hearing aids to be fitted, 39 subjects who at interview also stated that they had tinnitus took part in an experimental group study with the aim of investigating the effect of a hearing aid on tinnitus. No subject had any previous experience of hearing aids. The subjects were randomly allocated to a treatment and a waiting list control group. After an initial interview, the routine programme for the fitting of hearing aids started in the treatment group, while the waiting list control group had to wait for 6 weeks before starting the same hearing aid rehabilitation programme. The hearing aids were fitted exclusively for hearing purposes. As expected, the hearing aids improved the hearing capacity, but they did not reduce tinnitus as recorded on a visual analogue scale. According to information obtained at the final interview, there were significant differences in tinnitus between subjects who used their aid for more than 2 hours daily and those who used it for less than 2 hours. However, the results of scaling (pre- and post-fitting) did not support this finding. The discrepancy between the scaling and interview data is probably due to demand characteristics.