Abstract Functional near-infrared spectroscopy (fNIRS) has the potential for evaluating language and conversational interaction in an ecologically valid way given that participants can be seated and interacting with a conversational partner. Aphasia, an acquired language disorder, impacts language abilities, including conversational interaction. Understanding of cortical activity in people with aphasia for conversational tasks could provide an ecologically-valid index of brain function and recovery patterns in this population. This study provides pilot data in the use of fNIRS to evaluate language production for conversational responses in young (adult) neurotypical individuals, adults with post-stroke aphasia, and age-matched (i.e., older) neurotypical adults. Experiment 1 evaluated cortical activity for conversational responses vs. sentence repetition in a computer-based conversational question task. Experiment 1 results showed differentiation between experimental conditions (with greater fronto-temporoparietal cortical activity for question answering vs. repetition) in young healthy individuals that was not seen in the people with aphasia and age-matched individuals. Experiment 2 evaluated cortical activity for conversational responses in a structured conversational question task with a live interlocutor vs. sentence repetition. Experiment 2 results showed lower cortical activity across regions of interest in the age-matched group and greater cortical activity for question answering vs. repetition in bilateral temporal and left parietal regions of interest in the people with aphasia. This study provides preliminary evidence for the potential of fNIRS to characterize cortical activity after stroke for functional language tasks.
Braun et al. (Thu,) studied this question.