Agraphia caused by acute right parietal infarction

Area of Science:

• Neuroscience
• Neurolinguistics
• Cognitive Psychology

Background:

• Agraphia, the inability to write, is typically associated with lesions in the dominant language hemisphere.
• The angular gyrus is crucial for language processing, including writing.
• Understanding the neural basis of writing is essential for diagnosing and treating language disorders.

Observation:

• A 71-year-old Korean woman, previously illiterate but learning Korean script (Hangul), presented with acute agraphia.
• She could read but not write, with other language functions intact.
• Brain MRI revealed an acute infarction in the right angular gyrus.

Findings:

• The patient exhibited surface agraphia, characterized by phoneme-to-grapheme conversion errors and phonetic writing.
• Visual errors were also noted in her writing attempts.
• Functional MRI confirmed left hemisphere dominance for language, despite the right-sided lesion.

Implications:

• This case demonstrates that agraphia can result from injury to the non-dominant hemisphere, specifically the right angular gyrus.
• It suggests a role for the right angular gyrus in visuo-constructive aspects of writing.
• Findings expand our understanding of the neural networks underlying writing and language, particularly in relation to visual-motor integration.