Atypical cerebral laterality in adults with persistent developmental stuttering

Area of Science:

• Neuroscience
• Human Anatomy
• Speech and Language Pathology

Background:

• Consistent brain asymmetries include a larger right prefrontal and left occipital lobe.
• Atypical cerebral laterality is linked to increased neural risk for developmental stuttering.

Purpose of the Study:

• Investigate if atypical prefrontal and occipital lobe asymmetries are more prevalent in adults who stutter compared to fluent controls.
• Determine associations between lobar size/asymmetry patterns and stuttering severity or language abilities.

Main Methods:

• Volumetric MRI scans were used to measure prefrontal and occipital lobe volumes in adults with persistent developmental stuttering (n=16) and matched controls (n=16).
• Brain volumes were calculated proportionally to hemisphere volume.
• Language and stuttering assessments were conducted.

Main Results:

• No significant differences in hemisphere or total brain volumes were observed between groups.
• Control subjects exhibited typical asymmetries (larger right prefrontal, larger left occipital lobes).
• Adults who stutter showed atypical asymmetries; language deficits correlated with reduced prefrontal and occipital volumes.

Conclusions:

• Developmental stuttering is associated with atypical prefrontal and occipital lobe asymmetries.
• Language processing deficits in adults who stutter are linked to specific anatomical measures, including prefrontal and occipital volume reduction.