Multi-Task Transformer with Input Feature Reconstruction for Dysarthric Speech Recognition

Dysarthria is a motor speech disorder caused by damage to the part of the nervous system that controls the physical production of speech. It poses great challenges in building robust dysarthric speech recognition (DSR) due to the high inter- and intra-speaker variability. To this end, we propose a multi-task Transformer with input feature reconstruction as an auxiliary task, where the main task of DSR and the auxiliary reconstruction task share the same encoder network. The auxiliary task aims to reconstruct clear speech features from corrupted speech of healthy speakers (intra-domain) or dysarthric speakers (cross-domain). Further, to alleviate the imbalanced distribution of dysarthria data sets, we devise an adaptive rebalance sampling scheme to improve the utterance sampling frequency of dysarthric speech. Experimental results show that the proposed model considerably outperforms other baselines across speakers with varying severity of dysarthria.