With respect to hearing, again there is the difficulty in evaluating this function in an infant. Normally, after a few weeks of life, alert parents notice that the child makes a brisk startle to loud noises and a response to other sounds. A tinkling bell brought from behind the infant usually results in hearkening or head turning and visual searching, but a lack of these responses warns only of the most severe hearing defects. The detection of slight degrees of deafness, enough to interfere with auditory learning, requires special testing. To make the problem even more difficult, both a peripheral and a central disorder may be present in some conditions, such as the now infrequent disorder of kernicterus. Brainstem auditory evoked responses are particularly helpful in confirming peripheral (cochlear and eighth nerve) abnormalities in the infant and young child. After the first few months, impaired hearing becomes more obvious and interferes with language development, as described in the following text. It is of interest that the identification and remediation of early (infants) hearing defects by screening leads to higher scores on language tests later in childhood but not improved speech, according to a study by Kennedy and colleagues.
A considerable portion of neuropediatric practice is committed to the diagnosis and management of children with learning disabilities. These problems usually come to light in the school-age child (hence the term school dysfunction), whose aptitude for classroom learning is poorer than the child’s general intelligence. The medical referral may be from a parent, teacher, or psychologist. The clinician’s objective is to determine by history and examination whether there is (1) a general congenital developmental abnormality impairing intelligence; (2) a specific deficit in reading, writing, arithmetic, or attention, any one of which may interfere with the child’s ability to learn; (3) a primary sensory defect, particularly in audition; or (4) neither of these—for example, a behavior disorder or home situation that interferes with schooling.
Once diagnosis is achieved, the goal of management, undertaken in collaboration with psychologists and educators, is to fashion a program of remedial exercises that will maximize the child’s skills to a point commensurate with his talent and aptitude, and restore his self-confidence.
Disorders in the Development of Speech and Language
In the pediatric age period and extending into adult life, one encounters an interesting assortment of developmental disorders of speech and language. Many patients with such disorders come from families in which similar speech defects, ambidexterity, and left-handedness are also frequent. Males predominate; in some series, male-to-female ratios as high as 10:1 have been reported.
Developmental disorders of speech and language are far more frequent than acquired disorders, for example, aphasia. The former include developmental speech delay, congenital deafness with speech delay, developmental word deafness, dyslexia (special reading disability), cluttered speech, infantilisms of speech, and stuttering or stammering, and mechanical disorders such as cleft-palate speech. Often in these disorders, the various stages of language development described earlier are not attained at the usual age and may not be achieved even by adulthood. Disorders of this type, especially those restricted to the language areas of the cerebrum, are far more frequently a result of slowness in the normal processes of maturation than to an acquired disease. With the possible exception of developmental dyslexia (see further on), cerebral lesions have not been described in these cases, although it must be emphasized that only a small number of brains of such individuals have been thoroughly studied.
In discussing the developmental disorders of speech and language, we have adopted a conventional classification. Not usually included in such a classification are the many mundane peculiarities of speech and language that are usually accepted without comment: lack of fluency, inability to speak uninterruptedly in complete sentences, and lack of proper intonation, inflection, and melody of speech (dysprosody).