A scale for hearing aid benefit measures and auditory disability

Quoting disability scores or measures of hearing aid benefit based on percent correct word identification or on dB signal-to-noise ratio at criterion performance poses a communication problem as scientists and clinicians may have no intuitive understanding of the scales involved. In particular, percent correct does not allow direct comparison of differences obtained at different performance levels, for example by different subject groups. In circumstances where the better ear hearing levels are known to be a major determinant of disability, it is both possible and legitimate to transform performance measures such as percent correct into a dB HL equivalent. In two sets of data from clinical research projects this relationship is shown to be linear, allowing a particularly simple transformation and giving an already understood scale. This transformation procedure has been cross-validated against the acoustic gain used in a sample of patients with conductive losses where the hearing loss is purely an attenuation. The procedure is offered as a metric for expressing the benefits of management.