Resting-state brain connectivity in individuals with dyslexia

Resting-state brain connectivity in individuals with dyslexia

First Author: Kulpreet Cheema -- University of Alberta
Additional authors/chairs: 
Amberley Ostevik; Lindsey Westover; Bill Hodgetts; Truc Huynh; Julia Craig; Jacqueline Cummine
Keywords: Dyslexia, Neuroimaging, Reading, Adult Literacy, functional MRI
Abstract / Summary: 

Purpose. We examined the intrinsic brain connectivity in people with and without reading difficulties (i.e. dyslexia), and assessed the extent to which such connections were related to reading behaviour.
Methods.Behavioural data was collected from 15 adults with dyslexia and 19 control individuals on four reading subtests, including TOWRE real words and pseudowords, Word Identification and Word Attack. Following this, intrinsic brain connectivity data was collected via a resting-state sequence, where participants were asked to close their eyes and rest for 5 minutes while in the MRI. Between-group difference in resting-state connectivity was assessed and relationships between brain connectivity and reading behaviour was analyzed separately for skilled and impaired readers.
Results. Skilled readers had a stronger connection between the brain regions associated with speech representations (inferior frontal gyrus (IFG)) and sound/phonological processing (caudate), when compared to impaired readers. Impaired readers had stronger connections between speech representations (IFG) and areas related to visual-auditory integration (brainstem) and motor processing (supplementary motor area), when compared to skilled readers. For skilled readers, behavioural performance was primarily related to connections between brain regions that link speech and sound representations (IFG-posterior superior temporal lobe). In contrast, the behavioural performance for impaired readers was related to connections between brain regions that link speech and motor representations (IFG-sensorimotor, IFG-cerebellum).
Conclusions. Overall, there are different intrinsic brain connections for skilled and impaired readers, particularly between regions associated with sound and motor representations. Further, these differing brain connections are associated with behavioural reading performance. Such brain-behaviour relationships are important for advancing our understanding of reading difficulties.