DEFINITION
- Agraphia – an acquired deficit in the ability to produce written language
- Commonly used interchangeably with dysgraphia
HISTORY
- Term first employed by Ogle (1867) to describe pt who could speak but not write
- Since then, numerous classification systems have been proposed, but none universally accepted
- Two general nosologies:
- 1 longstanding tradition in context of clinical neurology; agraphias classified based on presence or absence of accompanying sxs such as aphasia, apraxia, visuospatial disorders
- 1 more recent scheme from cognitive neuropsych perspective
CLINICAL NEUROLOGY CLASSIFICATION
Aphasic Agraphias
- Fluent agraphias (ass’d w/ Wernicke’s, conduction aphasia, etc.)
- Easily produce writing of normal quantity and length, but…
- Paragraphic errors and lack of substantive words
- Nonfluent agraphias (ass’d w/ Broca’s, transcortical motor aphasia, etc.)
- Effortful, sparse production of written output
- Writing usually large and messy
- Prefer print, not writing
- Spelling errors due to letter omissions (in contrast to the omission of function words seen in aphasia)
- Alexia w/ agraphia
- results from lesion of inferior parietal lobe
- Gerstmann syndrome w/ agraphia
- similar to fluent agraphias
- Confusional state agraphia
- Pure agraphia
- writing deficit in absence of other aphasic sxs
Nonaphasic Agraphias
- Apraxic agraphias
- results from inability to correctly form letters
- Motor agraphia
- paretic agraphia
- micrographia
- agraphia w/ chorea
- agraphia w/ tremor
- writer’s cramp
- Callosal agraphia
- results from damage to CC and see unilateral agraphia
- Reiterative agraphia
- abnormal repetition of phrases, words, letters, etc.
- often seen w/ frontal lobe dementia
- Visuospatial agraphia
- Hysterical agraphia
COGNITIVE NEUROPSYCHOLOGY CLASSIFICATION
Phonological agraphia
- Syndrome that reflects impairment of nonlexical spelling route; impairment of sound-to-letter correspondences
- Pathway employs “sounding out” words
- Markedly impaired spelling of nonwords and unfamiliar words
- Can spell words with w/ which they are familiar, even if complex or irregular
Lexical agraphia
- Selective impairment of lexical (whole-word) spelling route that results in overreliance on spelling by sound-to-letter correspondence
- Pathway employs whole-word, visual image route; essential for spelling irregular words
- Inability to spell irregular words
- Rely on phonological route (so, “feign” becomes “fane”)
OTHER AGRAPHIA TERMS
Agraphia Spelling Disorders
- Deep agraphia
- syndrome similar to phonological agraphia in that there is impairment of nonlexical spelling route so that nonwords and unfamiliar words are misspelled
- also damage to lexical spelling route, resulting in semantic errors when writing
- Surface agraphia
- spelling d/o in which sublexical spelling-to-sound correspondences are used to assemble the spelling of the word
- words may be phonetically plausible but misspelled
- reverse phenomenon is phonological agraphia
- Jargon agraphia
- agraphia characterized by senseless combinations of letters or words
- Semantic agraphia
- loss of ability to incorporate meaning into spelling and writing
- semantically incorrect but correctly spelled dictated homophones (eg, doe for dough) may be written
- irregular words and nonwords are written correctly, however, demonstrating intact lexical and phoneme-to-grapheme conversion
Agraphia Writing disorders
- Allographic agraphia
- writing impairment ass’d w/ poor written production characterized by frequent omission errors w/ well-formed letter production
- although well formed, letter production may reflect wrong letter
- copying and oral spelling are spared
- Spatial agraphia
- writing impairment due to spatial deficits that affect nonlinguistic aspects of writing
- term applied to wide variety of phenomena such as writing on slant, uneven spacing of letters or words and blank spaces, ignoring left side of page, writing over other words, etc.