Is this a case of central plasticity?

The relationship between frequency discrimination ability and auditory map organization in the primary cortex has already been demonstrated in animal studies (Recanzone et al., 1993). Consequently, one could reasonably hypothesize that the improvement in DLFs at the cut-off frequency of a steeply sloping hearing loss reflects an overrepresentation of the lesion-edge frequency.

Furthermore, Thai Van et al. (2003) demonstrated that this improvement in DLF could not be explained by peripheral mechanisms such as the presence of otoacoustic emissions or the use of loudness cues to perform the frequency discrimination task. These authors also found dead cochlear regions in the vicinity of the cut-off frequency of all subjects, which is consistent with the hypothesis that auditory input deprivation at certain cochlear sites is necessary for any cortical reorganization to be observed (Rajan and Irvine, 1998). Consequently, they concluded that the DLF enhancement may reflect central plasticity and neural rearrangement.