Brain morphology in developmental dyslexia and attention deficit disorder/hyperactivity

Area of Science:

• Neuroscience
• Developmental Psychology
• Medical Imaging

Background:

• Brain asymmetry is crucial for typical cognitive development.
• Deviations in brain morphology are implicated in neurodevelopmental disorders.
• Understanding these differences aids in diagnosing and managing conditions like dyslexia and ADD/H.

Purpose of the Study:

• To investigate specific patterns of brain asymmetry in dyslexic and ADD/H children compared to controls.
• To identify unique neuroanatomical markers associated with dyslexia.
• To explore the relationship between brain morphology, handedness, and other health factors.

Main Methods:

• Magnetic Resonance Imaging (MRI) was used to scan 10 dyslexic, 10 ADD/H, and 10 control children.
• Measurements included anterior/posterior width and area, insular region length, and planum temporale length.
• Reliability of measurements was assessed and found to be excellent.

Main Results:

• Both dyslexic and ADD/H children exhibited smaller right anterior-width measurements than controls.
• Dyslexic children showed a bilaterally smaller insular region and a smaller left planum temporale.
• A significant difference in plana asymmetry was observed: 70% of controls and ADD/H had left-greater-than-right asymmetry, versus only 10% of dyslexics.

Conclusions:

• Atypical plana asymmetry (symmetric or reversed) appears unique to dyslexia and may indicate deviations in corticogenesis.
• While dyslexic children showed higher rates of left-handedness, it did not correlate with observed brain morphology variations.
• These findings highlight specific neuroanatomical differences in dyslexia and ADD/H, with unique patterns in dyslexia.