(3) The Motor Processes centrally disturbed.
a. Centro-motor Dysphasia and Aphasia, Aphemia, Asymbolia, Asemia.—Children have not yet learned, or have hardly learned, the use of language, although their intelligence is already sufficient. There is no longer any deficiency in the development of the external organs of speech, no muscular weakness, no imperfection of the nervous structures that effect the articulation of the separate sounds, for intelligence shows itself in the child's actions; he forms the separate sounds correctly, unintentionally; his hearing is good and the sensory word-memory is present, since the child already obeys. His not yet speaking at this period (commonly as late as the second year) must accordingly be essentially of centro-motor character.
In the various forms of this condition there is injury or lack of sufficient relative development either in the centro-motorium M or in the paths that lead into it, d, e, f as well as i, l, n.
α. Central Dysarthria and Anarthria.—In the child at the stage of development just indicated articulation is not yet perfect, inasmuch as while he often unintentionally pronounces correctly sounds, syllables, and single words, yet he can not form these intentionally, although he hears and understands them aright. He makes use of gestures.
Ataxic Aphasia (Verbal Anarthria).—The child that already understands several words as sound-combinations and retains them (since he obeys), can not yet use these in speech because he has not yet the requisite centro-motor impulses. He forms correctly the few syllables he has already learned of his future language, i. e., those he has at the time in memory as sound-combinations (sensory), but can not yet group them into new words; e. g., he says bi and te correctly, learns also to say "bitte," but not yet at this period "tibe," "tebi." He lacks still the motor co-ordination of words.
At this period the gesture-language and modulation of voice of the child are generally easy to understand, as in case of pure ataxic aphasia (the verbal asemia or asymbolia of Finkelnburg) are the looks and gestures of aphasic adults. Chiefly n, f, and M are as yet imperfectly developed.
Central Stammering and Lisping (Literal Dysarthria).—Children just beginning to form sentences stammer, not uttering the sounds correctly. They also, as a rule, lisp for a considerable time, so that the words spoken by them are still indistinct and are intelligible only to the persons most intimately associated with them.
The paths d and i, and consequently the centro-motorium M, come chiefly into consideration here; but L also is concerned, so far as from it comes the motor impulse to make a sound audible through M.
The babbling of the infant is not to be confounded with this. That imports merely the unintentional production of single disconnected articulate sounds with non-coördinated movements of the tongue on account of uncontrolled excitement of the nerves of the tongue.
Stuttering (Syllabic Dysarthria).—Stutterers articulate each separate sound correctly, but connect the consonants, especially the explosive sounds, with the succeeding vowels badly, with effort as if an obstacle were to be overcome. The paths i and l are affected, and hence M is not properly excited. S, too, comes under consideration in the case of stuttering, so far as impulses go out from it for the pronunciation of the syllables.