Explicit processing of melodic structure in congenital amusia can be improved by redescription-associate learning

Abstract

Congenital amusia is a neurodevelopmental disorder of musical processing. Previous research demonstrates that although explicit musical processing is impaired in congenital amusia, implicit musical processing can be intact. However, little is known about whether implicit knowledge could improve explicit musical processing in individuals with congenital amusia. To this end, we developed a training method utilizing redescription-associate learning, aiming at transferring implicit representations of perceptual states into explicit forms through verbal description and then establishing the associations between the perceptual states reported and responses via feedback, to investigate whether the explicit processing of melodic structure could be improved in individuals with congenital amusia. Sixteen amusics and 11 controls rated the degree of expectedness of melodies during EEG recording before and after training. In the interim, half of the amusics received nine training sessions on melodic structure, while the other half received no training. Results, based on effect size estimation, showed that at pretest, amusics but not controls failed to explicitly distinguish the regular from the irregular melodies and to exhibit an ERAN in response to the irregular endings. At posttest, trained but not untrained amusics performed as well as controls at both the behavioral and neural levels. At the 3-month follow-up, the training effects still maintained. These findings present novel electrophysiological evidence of neural plasticity in the amusic brain, suggesting that redescription-associate learning may be an effective method to remediate impaired explicit processes for individuals with other neurodevelopmental disorders who have intact implicit knowledge.