Patterns of Neural Functional Connectivity in Infants at Familial Risk of Developmental Dyslexia
Xi Yu1,2, Silvina Ferradal3, Jade Dunstan4
1State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China.
Insights
Infants with a familial history of dyslexia show altered brain functional connectivity (FC) in regions crucial for reading development. These early neural differences suggest a potential basis for dyslexia emerging in infancy.
Area of Science:
- Neuroscience
- Developmental Psychology
- Genetics
Background:
- Developmental dyslexia is a common heritable learning disability impacting 7-10% of the population.
- Individuals with dyslexia exhibit altered neural network organization in language and reading areas.
- The early emergence of these neural alterations remains largely unknown.
Purpose of the Study:
- To investigate if large-scale neural functional connectivity (FC) is altered in infants with a familial history of dyslexia (FHD).
- To determine if these early FC alterations predict later language and reading development.
Main Methods:
- A cohort study included 98 infants (35 with FHD, 63 without) recruited from Boston Children's Hospital.
- Structural and resting-state functional MRI scans were acquired.
- Multivariate pattern analysis identified distinct FC patterns differentiating infants with and without FHD.
Main Results:
- Infants with FHD showed distinct FC patterns in the left fusiform gyrus compared to controls.
- Classification accuracy for identifying FHD based on FC was 0.55.
- Key connections involved the left fusiform gyrus with frontal and parietal language/attention networks.
Conclusions:
- Familial history of dyslexia is associated with atypical functional connectivity in infants.
- These early neural alterations may impact word form recognition during reading acquisition.
- Longitudinal studies are needed to link these early network differences to later reading abilities.
Importance:
Developmental dyslexia is a heritable learning disability affecting 7% to 10% of the general population and can have detrimental impacts on mental health and vocational potential. Individuals with dyslexia show altered functional organization of the language and reading neural networks; however, it remains unknown how early in life these neural network alterations might emerge.
Objective:
To determine whether the early emergence of large-scale neural functional connectivity (FC) underlying long-term language and reading development is altered in infants with a familial history of dyslexia (FHD).
Design, Setting, And Participants:
This cohort study included infants recruited at Boston Children's Hospital between May 2011 and February 2019. Participants underwent structural and resting-state functional magnetic resonance imaging in the Department of Radiology at Boston Children's Hospital. Infants with FHD were matched with infants without FHD based on age and sex. Data were analyzed from April 2019 to June 2021.
Exposures:
FHD was defined as having at least 1 first-degree relative with a dyslexia diagnosis or documented reading difficulties.
Main Outcomes And Measures:
Whole-brain FC patterns associated with 20 predefined cerebral regions important for long-term language and reading development were computed for each infant. Multivariate pattern analyses were applied to identify specific FC patterns that differentiated between infants with vs without FHD. For classification performance estimates, 99% CIs were calculated as the classification accuracy minus chance level.
Results:
A total of 98 infants (mean [SD] age, 8.5 [2.3] months; 51 [52.0%] girls) were analyzed, including 35 infants with FHD and 63 infants without FHD. Multivariate pattern analyses identified distinct FC patterns between infants with vs without FHD in the left fusiform gyrus (classification accuracy, 0.55 [99% CI, 0.046-0.062]; corrected P < .001; Cohen d = 0.76). Connections linking left fusiform gyrus to regions in the frontal and parietal language and attention networks were among the paths with the highest contributions to the classification performance.
Conclusions And Relevance:
These findings suggest that on the group level, FHD was associated with an early onset of atypical FC of regions important for subsequent word form recognition during reading acquisition. Longitudinal studies linking the atypical functional network and school-age reading abilities will be essential to further elucidate the ontogenetic mechanisms underlying the development of dyslexia.
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