Letter position dysgraphia.

Area of Science:

• Cognitive Neuroscience
• Linguistics
• Psychology

Background:

• Acquired dysgraphia can manifest in various ways, affecting written language production.
• The graphemic buffer is crucial for storing and manipulating letter information during writing.

Observation:

• AE, a Hebrew speaker with acquired dysgraphia, exhibited a unique pattern of errors predominantly involving letter position (80%) rather than letter identity (7%).
• This letter position deficit was consistent across different writing tasks, output modalities (writing and typing), and word types (migratable, irregular, nonwords).
• Errors were concentrated in the middle of words, with a significant length effect observed in AE's writing.

Findings:

• The findings suggest a specific impairment in the graphemic buffer's letter order function, distinct from its letter identity processing.
• The selective deficit in writing, with no errors in reading, demonstrates the dissociability of letter position encoding between these two modalities.

Implications:

• This research provides evidence for a separate neural mechanism responsible for encoding letter order within the graphemic buffer.
• Understanding these specific deficits can inform therapeutic interventions for individuals with acquired dysgraphia.
• The study contributes to the broader understanding of the cognitive architecture underlying written language production.