Assessing semantic encoding and decoding models in stroke-induced aphasia

Project Summary People with aphasia struggle to translate their thoughts into language. One potential way to help people with aphasia is using brain-computer interfaces (BCIs) that decode intended speech from brain recordings. Recent studies have shown that continuous language can be decoded from semantic representations that encode the meaning of intended speech. However, semantic decoding has only been demonstrated in neurologically healthy participants, and current approaches do not accommodate the language comprehension impairments that often accompany language production impairments in aphasia. The long-term goal of this proposal is to develop BCIs that can improve communication in people with aphasia. This study has three goals: 1) to adapt existing semantic decoding approaches for people with aphasia, 2) to develop semantic decoding approaches that do not require any language training data from the person being decoded, and 3) to involve people with aphasia in the design of BCIs. To accomplish these goals, ten participants with aphasia and ten neurologically healthy participants will be recruited. Semantic decoders will be trained on functional MRI (fMRI) responses while participants listen to stories and watch movies. Semantic decoders will be tested on fMRI responses to perceived speech, perceived movies, and imagined speech. Collaborative design workshops will be held to assess when and how participants with aphasia envision using BCIs. These findings will evaluate the potential for using semantic decoding to improve communication in people with aphasia. This fellowship will provide the applicant with a unique interdisciplinary training experience, which will include the development of the necessary skills for a) administering language assessments, b) conducting neuroimaging experiments in participants with aphasia, and c) collecting and analyzing qualitative feedback from participants with aphasia. The applicant's sponsors and collaborators will provide mentorship in the areas of participant recruitment, language assessment, experimental design, functional neuroimaging, and thematic analysis. Together, these experiences will prepare the applicant for a successful independent research career.