Lecture
Methods for restoring reading in efferent motor alexia
We have described the reading impairment that occurs within the syndrome of sensory aphasia. There are also other types of alexia that arise as a result of speech disorders. These are the forms of alexia that are associated primarily with deficits in the motor aspect of speech and occur within the syndrome of efferent and afferent motor aphasia. We will not dwell in detail on the analysis of the structure of the reading impairment and the methods for its restoration in these cases, since these forms of alexia are directly related to deficits of oral expressive speech. In this section we will briefly describe only those methods and techniques that are directly aimed at overcoming reading deficits.
It is known that in efferent motor aphasia, oral speech can be severely impaired because of pathological inertia in motor processes. The resulting deficits in switching and the perseverations that occur disrupt oral speech, as well as reading, which may turn out to be less impaired than oral speech. A study of the alexia that arises in efferent motor aphasia has shown that the resulting perseverations lead to gross errors in reading. The patient recognizes and names individual letters, correctly repeats individual sounds, and can perceive a whole word at once while reading and understand its meaning. Reading aloud often becomes a matter of guessing; however, the cause of this in this case lies not in a deficit of sound discrimination, as is the case in sensory alexia, but in deficits of the switching mechanism, in perseverations.
In this case, reading is impaired at the motor link, and patients, in trying to overcome the motor difficulties of oral speech, often resort to guessing the meaning of the words, and even phrases, being read. Anticipation (the forestalling) of the meaning of a word leads to errors in reading it, in which both literal and verbal paraphasias can arise. Consequently, reading can be "guessing" not only in cases of impairment of the process of sound discrimination and defects in the span of perception, but also with impairment of the motor component in the structure of reading, and of the dynamics of the speech process.
In this case, the central mechanism of the reading impairment is deficits of switching, arising against a background of pathological inertia of speech processes. Here, it is first and foremost the link of sound-letter analysis that is impaired, but now because of perseverations, which constitute the central deficit in this form of alexia, rather than because of deficits of acoustic or optical perception. In cases of severe impairment, a higher level of reading — the level of comprehension — can also turn out to be defective. Let us give an example of efferent motor alexia.
Patient E., 45 years old, with a 4th-grade education, was operated on for an aneurysm of the supraclinoid portion of the left internal carotid artery. Neuropsychological examination revealed the presence of efferent motor aphasia in the patient; the deficits of oral speech were associated with impaired switching and perseverations. The patient recognized and read all individual letters correctly. However, perseverations already appeared when reading simple syllables. In experiments designed to provoke switching difficulties, perseverations appeared even when reading single letters. When reading words, phrases, and texts, the switching deficits increased as the amount of material increased and as the level of context rose.
The inert repetition of the syllable «па» (pa) crowded out any possibility of productive reading. Even more pronounced perseverations are found in reading syllables, words, and sentences where the kinetic melody is more complex and requires finer processes of switching.
Text
Кремль — сердце Москвы. Он стоит на холме. На башне — часы. Это куранты. (Kreml — serdtse Moskvy. On stoit na kholme. Na bashne — chasy. Eto kuranty. — "The Kremlin is the heart of Moscow. It stands on a hill. On the tower — a clock. These are the chimes.")
Patient
Кремль — сердце... Москва. Он стоит на схолпа. На навашне часы. На вашне куранты. (Kreml — serdtse... Moskva. On stoit na skholpa. Na navashne chasy. Na vashne kuranty. — a perseverative misreading in which "skholpa" replaces холме [kholme, "hill"], and "navashne"/"na vashne" replace башне [bashne, "tower"].)
Text
За деревней росли кусты сирени. Пастух под ней играл на свирели. Это было в России, цвела сирень, а в Монголии цвела магнолия. Через пески шел караван. Полковник вынул руку из кармана. Приказал полку остановиться на отдых. Повар разливал половником солдатам полка щи. (Beyond the village grew lilac bushes. A shepherd played the pipe beneath it. This was in Russia, where the lilac was blooming, while in Mongolia the magnolia was blooming. A caravan crossed the sands. A colonel took his hand out of his pocket. He ordered the regiment to stop and rest. A cook ladled cabbage soup out to the soldiers of the regiment. — the passage deliberately clusters the paronyms сирень/Монголия/магнолия and полковник/полк/половник to provoke perseveration, an effect specific to Russian.)
Patient
Да здраствени рослий кусты сирень/. Пастух под смей играла на серевновновании. Это было из России, цлела и цилень. И многолицини цвела маналия. Цанацу пески шел каравал. Палаци и кунул руку и канмана. Канлиназ полку осталиться и отдых. Полкалнипол полкала-нило полкалам полка щим. (a perseverative, largely neologistic misreading of the text above, contaminated by echoes of сирень, Монголия, магнолия, полковник, полк and половник.)
This last text was composed in such a way as to provoke perseverations in reading in the case of efferent motor alexia. An analysis of the errors shows that they arose predominantly from deficits of switching: of the 42 words in the text, only 10 words were read correctly, and the number of contaminations and guesses increased. Increasing the pauses between each word by means of a frame often led to successful reading.
E x a m p l e. За (pause) дере... деревней (pause) росли... (pause) ку... кусты (pause)... сердце... ой!... сирени. (Beyond [pause] the vil... village [pause] grew... [pause] bu... bushes [pause]... heart... oh!... of lilac — showing letter-by-letter reading, with an intrusion of сердце, "heart", from the earlier text.)
The central task of restorative learning in this case is to shift the reading process from guessing to a conscious level of analytical reading, but for this group of patients it is above all necessary to eliminate perseverations and the tendency toward guessing. This becomes possible by shifting the patient's attention to the pronunciation of individual sounds (accessible to the patient) while reading a whole word, and by artificially inhibiting the forward movement of the eyes along the line. The method described above is used — the frame method of reading, which limits guessing. After letter-by-letter reading has been practiced, the patient is moved on to syllable-by-syllable reading with the frame. This stage of training the patient usually takes a long time, and only after a well-practiced and consolidated method of syllable-by-syllable reading with the frame is the patient moved on to reading whole words within a phrase, likewise with the aid of a limiting frame. The teacher breaks the word into syllables set far apart from one another, which creates the conditions for pauses in reading that eliminate perseverations. Such methods of reading (the frame and pause methods), which limit the patient's guessing about the meaning of the word being read, removing the anticipation of subsequent sounds or syllables, and later of words, shift reading to the level of a conscious, analytical process, thereby helping to eliminate the tendency toward perseverations, which is the primary task of restoration in this form of reading pathology.
Methods for restoring reading in afferent motor alexia
A quite different picture of reading impairment is found in afferent motor alexia, which arises with a lesion of the postcentral gyrus. The central deficit in this case of the impairment of speech and reading is an impairment of the kinesthetic basis of articulations; the innervation of articulatory acts here loses its selectivity, and substitutions of some sounds (articulemes) for other, close ones, typical of these lesions, occur. Control over the process of reading is preserved in these patients; they know about their errors and try to correct them. As in the case of efferent motor alexia, here too it is above all sound-letter analysis that is impaired (the central deficit), but now because of deficits in the kinesthetic basis of speech. Reading becomes sharply deautomatized, a maximally conscious analytical process; the patient's entire attention is riveted on re-encoding the optical signs into the required articulations, so that comprehension lags behind perception. And yet articulatory difficulties not infrequently lead to genuine reading being replaced by guessing based on individual fragments of a word. Guessing in this case proceeds along the lines of the general meaning of the phrase and text; when reading, patients constantly resort to comparing the material just read with what was read earlier.
Some studies of reading have shown that the state of the level of comprehension is influenced by the degree of impairment of the sensorimotor level of reading in the forms of motor alexia described. Only severe motor deficits of reading can lead to an impairment of the comprehension of what is read. The least difficulty with comprehension occurs in cases of afferent motor alexia, where, even with a fairly severe impairment of the sensorimotor level, "inner reading" of short words and phrases may remain possible, and this helps in understanding what is read. This fact is a positive factor and is used accordingly in restorative learning.
The general direction of the method for restoring reading in this case calls for beginning the work with the restoration of the reading of whole words, in contrast to the restoration of reading in temporal and efferent motor alexia, which begins with the restoration of analytical (letter-by-letter and syllable-by-syllable) reading.
Work on restoring reading in afferent motor alexia begins only after the patient has developed a certain stock of active words. These words then serve as the first material for restoring reading. Later, the teaching of reading proceeds in parallel with the restoration of oral speech and becomes one of its most important supports.
At the first stage, much attention is devoted to strengthening the process of inner reading and increasing its scope. For this purpose, the patient is asked either to find, from a set of object or scene pictures, the corresponding word among a series of words given to him in printed form, or to find, from a set of given words, the corresponding pictures (the method of selection). Once inner reading becomes a habitual action, the patient is moved on to reading aloud the words present in his active vocabulary, with the support of pictures. Naturally, at this stage difficulties arise connected with the disintegration of articulemes and with the tendency to substitute some articulemes for other, similar ones. Overcoming this deficit remains the main task of this period of reading restoration and can, of course, take a considerable amount of time. Only after the ability to read individual words and short phrases aloud has been practiced is the task of practicing clear, articulated reading set. At the stage of restoring the reading of a phrase, and later of a text, it is necessary to make appropriate use of the comprehension of what is read and the positive influence of context on the accuracy and speed of reading. For this purpose it is useful to employ the "context method", which introduces the patient (even before reading the sentence or text) to the general sense and content of the reading to come. The patient is told the title of the text in advance and given a brief account of its content. Knowledge of the context activates the semantic level in the structure of text perception, which then begins to exert a positive influence on the motor aspect of speech perception and reading as well.
Comments