Dissociations between developmental dyslexias and attention deficits

Area of Science:

• Cognitive Neuroscience
• Developmental Psychology
• Educational Psychology

Background:

• Developmental dyslexia is a common learning disorder affecting reading.
• Attention deficits are sometimes hypothesized to underlie certain types of dyslexia.
• Distinct subtypes of both dyslexia and attention deficits exist.

Purpose of the Study:

• To investigate the relationship between specific dyslexia subtypes and attention deficits.
• To determine if attention deficits underlie developmental dyslexia or specific dyslexia types.
• To present double dissociations between dyslexia and attention deficits.

Main Methods:

• Tested 110 children and adults with dyslexia and/or attention deficits.
• Utilized extensive reading and attention test batteries.
• Identified dyslexia types and attention functioning (sustained, selective, orienting, executive).

Main Results:

• 55 participants showed a double dissociation between reading and attention.
• 21 had letter position dyslexia (LPD) without attention deficits.
• Specific dyslexias (LPD, attentional dyslexia, neglect dyslexia, surface dyslexia) dissociated from attention deficits.
• No consistent link found between any dyslexia type and a specific attention function.

Conclusions:

• Visuospatial attention deficits do not underlie the studied dyslexias.
• Findings challenge the hypothesis that attention deficits cause developmental dyslexia.
• Suggests distinct underlying mechanisms for dyslexia and attention deficits.