Intended Speech Classification with EEG Signals Based on a Temporal Attention Mechanism: A Study of Mandarin Vowels

Speech brain-machine interfaces (BCIs) offer an effective means for patients with voice disorders to communicate, and research on decoding electroencephalography (EEG) signals related to intended speech can help to understand the mechanisms of language production in the brain. This study classified the intended speech EEG signals of four Chinese vowels, utilizing a dataset collected from 10 participants. A proposed TA-EEGNet model was employed, incorporating a temporal attention module. The model achieved an accuracy of 49.47%, surpassing other prevalent EEG classification models. The average accuracy in the binary classification of vowels was 69.83%. The vowels /u/ and /ü/ were classified with the lowest accuracy, suggesting difficulties in classifying vowels with similar articulatory movements based on intended speech EEG signals. Furthermore, the research analyzed the classification performance using data of different brain regions. The results showed that the auditory cortex, Broca's and Wernicke's areas, prefrontal cortex, and motor cortex outperformed the sensory cortex, indicating their contributions in the intended speech process of Mandarin vowels. Results also showed left hemisphere dominance. These findings contribute to the study of the neural mechanisms underlying speech production and articulatory movements, emphasizing the potential of speech BCIs to improve communication for people with speech disorders.