DYSGRAPHIA: ACQUIRED
The loss or partial loss of the ability to write as the result of illness, accident or brain surgery. It is often associated with dyslexia, though it is possible for reading to be impaired without writing and vice versa.
Impairments involving the physical act of writing are termed peripheral dysgraphias. A patient may not be able to retrieve the letters that are needed, whether for the spelling of words or of non-words, but may be able to write letters perfectly. The reverse syndrome occurs where a patient is capable of a correct grapheme match but cannot form the letters.
There are three main types of central dysgraphia which are similar to the categories of central dyslexia. Some of the underlying causes may be similar.
In surface dysgraphia, once-familiar spellings cannot be retrieved but the patient makes an attempt to recall them on the basis of phonological information. Irregular spellings thus become regularised: biscuit ! BISKET. Sometimes patients show awareness that a spelling is irregular, but misallocate letters: yacht ! YHAGT. The condition may show impairment of the lexical (whole word) system.
In phonological dysgraphia, patients can spell familiar words correctly but are unable to devise spellings for dictated non-words. The condition appears to show impairment of the sound-spelling connection.
In deep dysgraphia, there are semantic errors like those of deep dyslexia, e.g. a patient wants to write chair but writes TABLE. Patients are better at writing concrete than abstract words. Typically, they are unable to write dictated non-words. The condition appears to show impairment of form-meaning associations; but a deep dysgraphic need not be a deep dyslexic.
See also: Disorder, Dyslexia: acquired
Further reading: Caplan (1992); Ellis (1993); Harris and Coltheart (1986)
