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Area 55b’s association with speech and pitch processing in chronic stroke: A resting-state fMRI study
Poster Session D, Saturday, September 13, 5:00 - 6:30 pm, Field House
Lamees Al-Hassan1, Haoze Zhu2, Arianna N. Lacroix3, Megan C. Fitzhugh4, Corianne Rogalsky1; 1Arizona State University, 2Indiana University School of Medicine, 3Purdue University, 4University of California San Diego
Recent studies of speech production and music perception have identified regions beyond the typical dual-stream speech processing network that are sensitive to both pitch motor control and pitch perception, including area 55b in dorsal premotor cortex. The present study uses resting-state functional MRI to investigate the connectivity of area 55b with the dual-stream speech network and how it may be related to aphasia symptomology. Eighteen chronic stroke survivors (12 with aphasia) and 32 matched control participants completed a series of speech, language, and cognitive assessments (including multiple auditory attention, working memory, and pitch repetition measures), in addition to structural and resting-state functional MRI acquisition. Results indicate that in the control group, left and right area 55b are significantly connected to both dorsal and ventral streams of the dual-stream speech network, and that left 55b connectivity with the left ventral stream, left dual-stream network, and the whole dual-stream network were significantly lower in the stroke group than in the control group. Multiple regression models in the stroke group revealed that performance on some aphasia and cognitive measures were significantly predicted by left or right 55b connectivity to portions of the dual-stream speech network. For example, fluency was significantly predicted by right 55b connectivity with left dual-stream network regions, while naming was significantly predicted by left 55b connectivity with left dual-stream network regions, particularly with the left ventral stream. Auditory orienting attention was significantly predicted by left 55b connectivity with the whole dual-stream network, particularly left dual-stream regions. Overall, these findings suggest that premotor speech control regions such as area 55b are highly connected with the dual-stream speech network, and that their connectivity with the ventral stream may be particularly impaired in individuals with aphasia. Understanding area 55b and dorsal premotor speech regions is a promising direction to better understand the neurobiology of speech and the neural resources available to stroke survivors during aphasia rehabilitation.
Topic Areas: Speech Motor Control, Disorders: Acquired