Agraphia

Lesions or seizure activity localized to this vicinity lead to deficiencies involving the elementary motoric aspects of writing; i.e. agraphia. Grapheme formation becomes labored, incoordinated, and takes on a very sloppy appearance. Cursive handwriting is usually more disturbed than printing. In cases of well circumscribed lesions, usually there are no gross deficiencies of motor functioning or speech, although mild articulatory disturbances may be observed (e.g. lisping) as well as abnormalties involving fine motor control. In cases of pure (frontal) agraphia, spelling may or may not be affected, whereas with parietal lesions spelling as well as writing is often abnormal. Rather, with left frontal lesions more frequently there are disturbances of grapheme selection such that the patient may seem to have "forgotten" how to form certain letters and/or may misplace or even add unnecessary letters when writing. When spelling orally or typing the ability to spell is often better preserved. Damage localized to this vicinity can be secondary to perinatal trauma, tumors, or vascular abnormalities. Disturbances involving constructional or manipulospatial functioning are not apparent. In fact, one such patient whose damage was secondary to birth injury, although able to write or print only with great difficulty, was able to draw and paint with some professional acumen. However, his ability to copy letters was severely effected. Hence, disturbances secondary to lesions localized to Exner's area limited to abnormalities involving linguistic-symbolic grapheme motor control.

It has been argued that the sensory motor engrams necessary for the production and perception of written language are stored within the parietal lobule of the left hemisphere. In fact, given that the parietal lobes are concerned with the hands and lower visual fields, they not only guide and observe hand movements, but learn and memorize these actions, including those involved in writing.
 * Left Parietal Lobe: **

Hence, when lesioned, patients sometimes have difficulty writing and forming letters due to an inability to access these engrams. Writing samples may be characterized by mispellings, letter ommissions, distortions, temporal-sequential misplacements, and inversions. Sometimes agraphia is accompanied by alexia; inability to read..

In some cases acalculia may be associated with an alexia and/or an agraphia for numbers, as well as aphasic abnormalities (referred to as aphasic acalculia. Individuals with this disorder are unable to recognize or properly produce numbers in written form.
 * ALEXIA/AGRAPHIA FOR NUMBERS**

Ex: May be unable to write out or point to the number "4" vs the number "7" or the letter "B".

Lesion is usually in the **left inferior parietal lobule** and localized within the angular gyrus. Not all patients are aphasic however. See also Acalculia