Agraphia is defined as the inability to express thoughts in writing, despite intact motor function, comprehension, and basic literacy skills. It is distinct from motor deficits that prevent writing (e.g., paralysis) and often reflects cortical or subcortical lesions affecting language processing or motor planning areas.

Pathophysiology

Agraphia commonly results from lesions in the dominant hemisphere, particularly the left parietal and frontal lobes, which are responsible for language, spelling, and motor planning of writing. Types of agraphia include:

• Aphasic agraphia: Spelling, grammatical, and syntactic errors occur due to language processing deficits, often associated with Broca’s or Wernicke’s aphasia.

• Constructional agraphia: Correctly spelled words are reversed or disordered, reflecting impaired visuospatial or organizational processing, often from right parietal or occipital lesions.

• Apraxic agraphia: Inability to form letters correctly despite intact motor function, often due to premotor cortex or parietal lobe lesions.

Agraphia is most commonly observed after ischemic or hemorrhagic stroke, but can also occur with traumatic brain injury, neurodegenerative disorders (e.g., Alzheimer’s disease), tumors, or focal cortical lesions.

Examination Technique

• Patient history: Ask about onset, progression, and patterns of writing difficulty. Note whether comprehension and oral expression are preserved.

• Writing assessment:

  • Ask the patient to write a simple sentence and note errors in spelling, grammar, or letter formation.

  • Ask the patient to copy printed text to distinguish motor vs. language deficits.

  • Ask the patient to write from dictation to identify phonological or syntactic errors.

• Neurologic examination: Evaluate for hemiparesis, aphasia, visual field deficits, or neglect.

• Imaging: MRI or CT may localize lesions affecting language and motor planning cortices.

Clinical Utility

• Localization of brain lesions: Helps identify dominant parietal or frontal lobe involvement.

• Stroke assessment: Common sequela of left hemispheric stroke affecting language centers.

• Neurodegenerative evaluation: Can indicate progression of dementias, primary progressive aphasia, or corticobasal degeneration.

Differential Diagnosis

Pediatric considerations

• Rare in children, usually associated with stroke, traumatic brain injury, or congenital lesions.

• Early literacy intervention is critical to mitigate long-term learning deficits.

Geriatric considerations

• Common in elderly patients with stroke or neurodegenerative disease.

• Writing difficulties may precede other cognitive deficits in dementia.

• Assessment should include evaluation of hand tremor, arthritis, and visual acuity to rule out motor or sensory contributors.

Limitations

• Writing deficits may be confounded by motor weakness, tremor, or poor vision.

• Requires patient cooperation and literacy baseline for accurate assessment.

• Imaging is essential to distinguish cortical vs. subcortical causes.

Patient counseling

• Explain that writing difficulty is neurologically based and not due to laziness or lack of education.

• Encourage occupational therapy and cognitive rehabilitation to maximize functional recovery.

• Recommend adaptive strategies, such as typing or voice-to-text software, to maintain communication.

Conclusion

Agraphia is a distinct neurocognitive disorder of written expression, most commonly resulting from cortical lesions in the dominant hemisphere. Timely recognition, thorough assessment, and targeted rehabilitation are critical for preserving communication, supporting daily activities, and improving patient outcomes after stroke or other neurologic injuries.

References

1. Buttaro TM, Tybulski J, Bailey PP, Sandberg-Cook J. Primary Care: A Collaborative Practice. St. Louis, MO: Mosby Elsevier; 2008:444–447.

2. McCance KL, Huether SE, Brashers VL, Rote NS. Pathophysiology: The Biologic Basis for Disease in Adults and Children. Maryland Heights, MO: Mosby Elsevier; 2010.

3. Mesulam MM. Principles of Behavioral and Cognitive Neurology. 3rd ed. New York, NY: Oxford University Press; 2009.

4. Kandel ER, Schwartz JH, Jessell TM. Principles of Neural Science. 5th ed. New York, NY: McGraw-Hill; 2013.