Neural networks mediating sentence reading in the deaf

Area of Science:

• Neuroscience
• Cognitive Science
• Linguistics

Background:

• Understanding the neural basis of reading is crucial for educational and clinical applications.
• Deafness may influence the brain networks supporting reading due to altered sensory input and language experience.

Purpose of the Study:

• To investigate the neural underpinnings of sentence reading in deaf populations.
• To examine how varying degrees of hearing loss and English language knowledge impact reading-related brain activity.
• To explore the role of the auditory cortex and its connectivity in deaf readers.

Main Methods:

• Functional magnetic resonance imaging (fMRI) was used to scan three groups: deaf signers, oral deaf individuals, and hearing individuals.
• Participants were matched for reading comprehension and performed sentence reading tasks.
• Functional connectivity analyses were conducted on the superior temporal gyrus (STG) regions.

Main Results:

• A shared neural network of left perisylvian areas was observed for sentence reading across all groups.
• Deaf individuals exhibited greater bilateral superior temporal gyrus (STG) recruitment compared to hearing individuals.
• Increased hearing loss correlated with greater left STG recruitment in deaf individuals.
• Connectivity from the left STG to semantic processing areas was higher in deaf groups, while connectivity to speech-based processing areas was higher in hearing and oral deaf groups.

Conclusions:

• The brain utilizes a common network for reading, but auditory deprivation leads to functional reorganization, particularly in the auditory cortex.
• Both the extent of hearing loss and language experience significantly shape the functional reorganization of auditory areas for visual language processing.
• Deaf readers may rely differently on semantic versus phonological processing pathways during reading.