Agraphia

Agraphia represents acquired impairments of writing ability secondary to damage or dysfunction of the central nervous system. Impairments caused solely by motor dysfunction (e.g. hand paresis or tremor) are not considered to be forms of agraphia .

Clinical presentation

Agraphia is rarely an isolated entity, and commonly manifests itself together with other language or visuospatial defects, apraxia, or dementia. In the characteristic Gerstmann syndrome agraphia co-occurs with acalculia, left-right disorientation, and finger agnosia.

The etiology of agraphia is diverse with stroke, traumatic CNS injury, or dementia (Alzheimer disease) being the most common culprits. Agraphia may result from focal damage to the left dorsolateral frontal lobe, but also from left temporal and parietal injuries.

In less severe cases agraphia may manifest as e.g. an increased frequency of spelling errors in writing, whilst in severe forms even single letter writing may become impossible. Interestingly, number writing ability is often relatively preserved, as is writing the own name of the patient .

Major forms of agraphia:

• pure agraphia: isolated agraphia, without other dysfunctions, such as dementia, visuospatial impairment, or aphasia
• spatial agraphia (e.g. inability to maintain a horizontal writing direction, incorrect grouping and fragmentation of words)
• micrographia: progressively decreasing size of letters in a sentence
  • often associated with parkinsonism and Alzheimer disease
• dysexecutive agraphia: diminished ability to express thoughts in writing
  • commonly associated with prefrontal and frontal pathology