Learning on auditory discrimination tasks in normal-hearing listeners: Implications for hearing rehabilitation

Abstract

Hearing rehabilitation extends beyond simply fitting a hearing aid or cochlear implant. To improve the benefit of these devices, it must be established which auditory abilities can be improved with training. Toward this end, learning in normal-hearing listeners was examined on five auditory discrimination tasks: frequency, intensity, interaural-time-difference (ITD), interaural-level-difference (ILD), and duration. Because the same training regimen was used throughout, any differences in the learning patterns across these trained discriminations likely reflect differences in the plasticity of the underlying mechanisms, at least for that regimen. The influence of training was assessed by comparing the improvements in discrimination threshold on trained and untrained conditions between listeners who were given multiple-hour practice on a single discrimination condition and those who were not. Learning on the five tasks followed one of two general patterns. For ITD and intensity discrimination, multiple-hour practice did not lead to greater learning than that seen in untrained listeners. In contrast, for ILD, duration, and frequency discrimination, such practice yielded greater learning, but only on a subset of conditions. The differences in the plasticity across these auditory tasks in normal-hearing listeners imply that cochlear-implant users may benefit more from training on some tasks than others. [Work supported by NIH.]