Presentation

Ting Qi¹, Yulia Oganian^2,3, Maria Luisa Mandelli¹, Christa Watson Pereira¹, Abigail Licata¹, Rian Bogley¹, Nicole Yabut¹, Matthew Neylan¹, Edward Chang², Maria Luisa Gorno-Tempini¹; ¹Department of Neurology, University of California San Francisco, United States, ²Department of Neurological Surgery, University of California San Francisco, United States, ³Center for Integrative Neuroscience, University of Tübingen, Tübingen, Germany

Developmental dyslexia (DD) is a neurodevelopmental reading disorder, generally associated with phonological deficits and often non-speech auditory impairments. For instance, perception of acoustic edges in sound amplitude modulations, a critical cue to syllable structure, is reported to impair in some DD cohorts. Yet, little is known about the brain basis of auditory deficits in DD. Here, we examined the relationship between acoustic edge perception in DD and anatomical structures of the superior temporal gyrus (STG), a region strongly implicated in phonological and acoustic edge processing. Participants (50 children with DD, aged 7-15y) completed an amplitude rise-time discrimination task (RT) to assess acoustic edge perception, alongside a battery of phonological and reading tests. Brain surface measures were obtained from T1-weighted images, and T2-weighted images were also included to estimate myelin content for a subgroup of children. We found that RT performance positively correlated with both reading and phonological abilities. Crucially, a higher local gyrification index in the left posterior STG (pSTG) was associated with better RT performance, but was not related to phonological abilities. This suggests independent contributions of the STG to non-verbal auditory deficits in DD. In addition, the local gyrification index of the left pSTG decreased with increasing myelin content, which is suggestive of the hypermyelination of the left pSTG in DD. Overall, our results show that the neurodevelopment of the left temporoparietal region may underlie individual variations in auditory processing in DD. This constitutes the first evidence linking behavioral auditory deficits and brain structure in DD, providing a path towards understanding individual variability in DD.

Topic Areas: Disorders: Developmental, Reading