Brain lateralization and severity of stuttering in children

Area of Science:

• Neuroscience
• Speech and Language Pathology
• Cognitive Psychology

Background:

• Cerebral lateralization, the brain's functional specialization of hemispheres, plays a crucial role in cognitive processes like visual perception.
• Stuttering, a complex speech disorder, has been associated with atypical brain organization, but its relationship with visual processing lateralization remains under investigation.

Purpose of the Study:

• To investigate cerebral lateralization in visual word perception among individuals with varying degrees of stuttering severity.
• To determine if functional brain organization for visual processing differs between severe stutterers, mild stutterers, and fluent speakers.

Main Methods:

• A visual word identification task was administered to 9 severe stutterers, 11 mild stutterers, and 48 fluent speakers.
• Words were briefly presented (20 ms) in either the left or right visual field.
• Participants identified the presented word by pointing to it on a response card; errors were analyzed based on visual field.

Main Results:

• Fluent speakers and mild stutterers demonstrated left hemisphere superiority in processing visual words.
• Severe stutterers exhibited a right hemisphere advantage for visual word processing.
• A correlation was observed between stuttering severity and altered functional brain organization.

Conclusions:

• The findings suggest that the severity of stuttering is closely related to atypical functional brain organization in visual perception.
• Severe stuttering may involve a shift in the dominant hemisphere for visual word processing compared to milder forms or typical fluency.