Cross-modal plasticity after auditory working memory training in stroke

The present study investigated cross-modal plasticity after a course of auditory working memory training. Two clients with stroke completed auditory n-back tasks (1-,2- and 3-back) in a graded manner for a total of 20 hours over a six-week period. Neural activations on auditory and visual n-back tasks (1- and 2-back) were assessed before and after training. The two clients demonstrated different patterns of results. The client with intact fronto-parietal network demonstrated substantial improvement on n-back performance. Additionally, the neural activation in the fronto-parietal network subsided after training in both the auditory and visual n-back tasks, and there were extensive activationsin the cerebellum. In contrast, the client with a largearea of damage in the fronto-parietal network showed no evidence of frontal and parietal activation before training, and the performance of the n-back tasks was comparatively poor and was mainly supported by temporal lobe activities. The results suggest that effective cross-modal transfer after stroke require an intact fronto-parietal network. Other regions like the cerebellum might also contribute to cross-modal transfer. Future larger scale study is recommended to disentangle individual differences in neural activity after training.