Lecture
Another type of optical agraphia consists in the loss of the generalized optical image of a letter denoting a specific sound: in this case the grapheme ceases to perform the function of denoting a particular sound.
It is known that in perception there exist different levels of generalization of the perceived object. First a global image is perceived, under which a number of objects fall that are, on the whole, similar to the one perceived. This stage of perception and recognition of the object (the letter) proceeds without an analysis of all the features of the object and of the specific features peculiar only to it. And only after the subsequent stage of analytic examination of the object (the letter), at which the image is enriched by a whole series of features and by the main distinguishing feature, does the stage of generalized perception of the image of the object set in again, an object now recognized and included (generalized) into a group of objects on the basis of its distinguishing, sense-differentiating features.
On this basis the constancy of the generalized image of the object, of the phenomenon (including the letter), is also formed. It is precisely this higher form of generalization, based on the isolation of the essential features of the object, that is impaired in optical agraphia and alexia. But the capacity for global (or lower-level) perception of objects (and letters) is preserved. However, the phenomenon of the «estrangement» of the grapheme, the letter, from its meaning and sense sets in, just as in acoustic agraphia a phenomenon of semantic estrangement is observed, but not of the letter — of the sound.
Patients with this form of agraphia readily distinguish speech sounds, but in them the constant and generalized image of the letter disintegrates. The impairment of the constancy and generality of the letter is the central mechanism of optical agraphia. The central defect in this case is an impairment of the differentiation of the optical image < of the letter, the replacement of some letters by others close in their overall optical image and structure (а — о — е, и — п — н, ш — и — п, с — х — к, в - р, Б – В – Р (a — o — ye, i — p — n, sh — i — p, s — kh — k, v-r, B–V–R) etc.).
In the clinical picture of optical agraphia, one finds searching for the needed letter, errors of the type of replacing one letter with another similar in shape (literal optical paragraphias), slowness |and voluntariness of the process of writing.
In the psychological picture of the disorder for this form of agraphia |is characteristic, on the one hand, a blurring of the image of the letter, defects in isolating its essential components that carry meaning — micro-features (Б — В, И — И, Г — П — Т, Н — Пи т.д. — B–V, I–I, G–P–T, N–P, etc.), and, on the other hand — the disintegration of the generalized image (the highest level of generalization) of the letter and [its replacement by one that is concrete, singular, and peculiar only to the given subject (some patients, for example, could write the letter «Д» only as «д», the letter «Р» only as «Р»). Because of the defect in the generality of the image of the letter, these patients experienced difficulty in the transition from one form of a letter to another within a single grapheme (Д, Д д). It is precisely in this connection that, in this form of agraphia, writing in one particular script often remains more preserved — either handwritten or printed — with difficulty or complete impossibility of switching from one script to another. What is impaired above all are such types of writing as independent writing and dictation; copying remains more preserved.
This type of agraphia occurs within the syndrome of optical object agnosia, acalculia, alexia. Cases of writing disorder are frequently encountered,
• in which the graphic image of the letter and its spatial arrangement are preserved, but its meaning disappears. Such patients often denote
• sounds correctly isolated from the speech stream with non-corresponding [letters. This disorder is classified as an optic-mnestic disorder of writing, which has a direct bearing on the pathology of the speech organization of optical gnosis. This form of agraphia lies at the junction of speech and optical processes and often occurs within the syndrome of amnestic aphasia. It is known that speech organizes all mental functions and regulates their course. In this type of agraphia a mismatch between speech and perceptual processes is clearly revealed, underlain, possibly, by an impairment of inter-analyzer connections — between the speech-motor and visual analyzers.
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This form of agraphia is complex and requires special attention to the methodological side of restorative learning. It often occurs within the syndrome of amnestic aphasia, in which naming is also impaired, but not of letter signs — of objects. Restorative learning here must be directed at restoring images — of objects and of letter signs — and their connection with naming. Here the same methods can be applied that were developed and described by us in another work1.
Thus, the essence of all forms of optical agraphia lies in the impairment of the grapheme not as a unit of speech, but as a unit of optical and optic-spatial perception. In all these cases the grapheme is impaired as a unit of writing, closely linked to its sound and kinesthetic levels. However, there is a form of agraphia in which the grapheme itself is not impaired, but only its shape, its execution, is impaired, and this occurs owing to an impairment of optic-motor connections. In writing letters, patients of this kind distort only the shape of the letter itself, while the grapheme remains preserved. This is the so-called apracto-agnostic form of optical agraphia. Patients of this type never write, say, К or С instead of В. They always write the grapheme that was given to them. They never replace one letter with another. In writing they easily move from writing one letter to another within a single grapheme (from the capital to the lowercase form, from the handwritten to the printed form). They know that Д, д, Ъ (D, d, the hard sign) are letters of the same grapheme, but in writing them the graphic shape of the letter itself is distorted. Here the letter usually disintegrates according to the same laws — as any other optical structure — not as a unit of speech, but as a drawing, as an optic-motor unit.
Here a variety of methods are very useful, promoting the restoration of the interaction between visual gnosis and praxis, and the restoration of optic-motor connections. The most effective method here may prove to be the method of drawing, in all its forms: copying, completing a drawing, drawing from a word and spontaneous drawing, drawing objects and geometric figures, etc. And only after this work does one move on, not to writing, but to drawing letters, with a subsequent transition to writing them as the letter sign of a sound, of speech.
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