Agraphia
Agraphia
Agraphia or dysgraphia is a loss or disturbance of the ability to write or spell. Since writing depends not only on language function but also on motor, visuospatial, and kinesthetic function, many factors may lead to dysfunction. Agraphias may be classified as follows:
- Central, aphasic, or linguistic dysgraphias:
- These are usually associated with aphasia and alexia, and the deficits mirror those seen in the Broca/anterior and Wernicke/posterior types of aphasia; oral spelling is impaired. From the linguistic viewpoint, two types of paragraphia may be distinguished, viz.:
surface/lexical/semantic dysgraphia: misspelling of irregular words, producing phonologically plausible errors (e.g., simtums for symptoms); this is seen with left temporoparietal lesions (e.g., Alzheimer’s disease, Pick’s disease); deep/phonological dysgraphia: inability to spell unfamiliar words and nonwords; semantic errors; seen with extensive left hemisphere damage.
- These are usually associated with aphasia and alexia, and the deficits mirror those seen in the Broca/anterior and Wernicke/posterior types of aphasia; oral spelling is impaired. From the linguistic viewpoint, two types of paragraphia may be distinguished, viz.:
- Mechanical agraphia:
- Impaired motor control, due to paresis (as in dominant parietal damage), dyspraxia (may be accompanied by ideomotor limb apraxia), dyskinesia (hypokinetic or hyperkinetic), or dystonia; oral spelling may be spared.
- Neglect (spatial) dysgraphia:
- Associated with other neglect phenomena consequent upon a nondominant hemisphere lesion; there may be missing out or misspelling of the left side of words (paragraphia); oral spelling may be spared.
- Pure agraphia:
- A rare syndrome in which oral language, reading and praxis are normal.
A syndrome of agraphia, alexia, acalculia, finger agnosia, right-left disorientation and difficulty spelling words (Gerstmann syndrome) may be seen with dominant parietal lobe pathologies.
Writing disturbance due to abnormal mechanics of writing is the most sensitive language abnormality in delirium, possibly because of its dependence on multiple functions.
References
Benson DF, Ardila A. Aphasia: a clinical perspective. New York: OUP, 1996: 212-234
Roeltgen DP.Agraphia. In: Heilman KM, Valenstein E (eds.). Clinical neuropsychology (4th edition). Oxford: OUP, 2003: 126-145
Cross References
Alexia; Allographia; Aphasia; Apraxia; Broca’s aphasia; Fast micrographia; Gerstmann syndrome; Hypergraphia; Macrographia; Micrographia; Neglect; Wernicke’s aphasia
