Exploring the Interplay of Prosody, Language Skills, and Brain Connectivity: A Stroke Resting State fMRI Study

This thesis explores the interplay of aphasia symptoms and brain connectivityusing resting-state functional Magnetic Resonance Imaging (MRI). The research presented here is a step towards understanding the neural basis of linguistic prosody in particular, and its relationship with language impairments in post-stroke aphasia. This study focuses on examining the functional connectivities of the frontal-parietal control network and the dorsal attention networks with specific regions within traditional language networks, as a growing body of research suggests that prosodic cues in speech may recruit control and attention networks to support language processing. Using resting- state fMRI, the present study examined the functional connectivity of the frontal parietal control and dorsal attention networks with traditional language regions in 28 participants who have experienced a stroke-related language impairment (i.e. aphasia) and 32 matched neurotypical adults. Overall, the study reveals significant functional connectivity differences of the frontoparietal control and dorsal attention networks between the stroke and control groups, indicating that individuals with aphasia have brain connectivity differences beyond the traditional language networks. Multiple regression analyses were then used to determine if functional connectivities of the frontoparietal control and dorsal attention networks within themselves and with traditional language regions could predict aphasia symptoms, as measured by the Western Aphasia Battery (WAB). Overall, the regression results indicate that greater functional connectivity between the frontoparietal control and dorsal attention networks with traditional language regions is associated with improved language abilities, with different connectivities predicting different types of aphasia symptoms (e.g. speech, naming / word finding, auditory comprehension, overall impairment). Altogether this study contributes to the understanding of the neural bases of language impairments post-stroke, highlighting the intricate connections between language and other cognitive networks, which may be mediated by prosody.