Agraphia

AGRAPHIA (from Greek a - negative particle, and grapho - I write), a disorder of writing resulting from the loss of ability to use written signs, symbols of words, phrases, etc. ("symbols of symbols"). Most often it is associated with aphasia (see), and also frequently with alexia (see). Agraphia in apraxia (see) stands apart. In severe cases, agraphia patients cannot write a single letter; in others - they write letters, distorting their form, replacing one with another; in thirds - they, being able to write letters correctly, are unable to write words, let alone sentences. Omitting letters, syllables, words and endings, they sometimes produce a completely incomprehensible set of words (paragraphia). Sometimes in them, as in aphasia, some word or syllable gets stuck, which they repeat endlessly in writing (polygraphia). In severe cases, both voluntary writing and writing under dictation, and copying from a book, and even copying from a book in printed letters are disrupted. In some cases, however, only one of the listed functions is impaired. According to classical schemes (see Aphasia), each form of aphasia corresponds to a specific combination of writing disorders. However, clinically it is more correct to consider different manifestations of A. as an expression of varying degrees of lesion and as a result of different localization of the focus. A. is caused by foci in the second frontal gyrus (B), in front of the motor center of the hand - the agraphia center of Exner (see figure in the article Aphasia) in the parieto-occipital region, at the transition of gyr. angularis into the second occipital gyrus - field 19 according to Brodmann or OA according to Economo (agraphia center of Déjerine), or finally in the first temporal gyrus (2) at the border with gyr. supramarginalis - field 22 according to Brodmann or TA according to Economo (agraphia center of Wernicke-Pick). The predominance of the left hemisphere over the right is at least not proven. All the mentioned places form a single apparatus, the parts of which are connected by association pathways (fasciculus arcuatus). It should be assumed that this area is not, as the classics thought, a repository of "graphic images of word memory", but that the function of this apparatus consists, apparently, in transmitting directions to the right, left, up and down from the centers of vision and speech to the motor apparatus. - The indicated foci can sometimes be differentiated according to the clinical picture. If A. is combined with significant motor aphasia, one should think of the Exner center; if writing under dictation is most severely impaired - of the Wernicke-Pick center. If copying from a book is extremely impaired and is even worse than voluntary writing, the focus should most likely be localized in the Déjerine center. In the latter case, alexia is also often encountered. Apraxic agraphia is not difficult to distinguish from the described forms, due to the fact that apraxia is noted in it besides writing and it usually affects one hand, more often the left. In true agraphia, the patient is unable to write with either hand. One type of agraphia consists in that patients write as writing is reflected in a mirror. - On the etiology of agraphia see Aphasia. The prognosis is much better than in aphasia. Treatment, besides causal, consists in systematic exercises - in copying, writing under dictation, written composition. M. Krol.