Masking effects and tinnitus as explanatory variables in hearing disability.

In cases of substantial auditory handicap, the degree of pure-tone hearing loss or hearing loss for speech is seen as the primary determining factor. Sometimes the presence of tinnitus complaints and disproportionate masking effects of noise on speech reception are seen as aggravating factors. To investigate the relevance of tinnitus and masking effects in the context of hearing disability, four factorial designs with self-perceived hearing disability as the dependent variable were submitted to an analysis of variance. Impact of masking and tinnitus complaints were treated as independent variables with two levels and were each combined with a second independent variable to form a 2 x 2 fixed factor statistical model. This second independent variable was either hearing loss for pure tones (first and second model) or speech reception ability (third and fourth model). Both hearing loss for pure tones and speech reception capability were found to be significant explanatory factors for hearing disability. Impact of masking, if juxtaposed to average pure-tone hearing loss (first model), also came out of the analysis as a significant factor in hearing disability, whereas the tinnitus factor did not reach significance levels. No significant interactions between factors were found. The results support the idea of the differentiating audiogram-based disability estimates by taking noise susceptibility into account. The findings also suggest in an equivocal relation of tinnitus with hearing disability, which prevents it from being a straightforward disability predictor.